Flußquantifizierung von intrakardialen Shuntvolumina unter Verwendung der MR-Phasenkontrast-Technik in Atemanhaltephase

PURPOSE Comparison of a breath-hold, velocity-encoded, phase-difference magnetic resonance (MR) sequence for intracardiac shunt flow measurement with the invasive shunt size determination by oximetry. PATIENTS AND METHODS 10 patients with different cardiac shunts (6 ASD/3 VSD/1 PDA) and four healthy individuals were investigated using a 1.5 Tesla Siemens Vision system. For flow measurements a breath-hold, velocity-encoded, phase-difference magnetic resonance (MR) sequence was used ('through plane', FLASH 2D-sequence, TR/TE 110/5 ms, 'velocity encoding' 250 cm/s). Mean flow (ml/R-R interval) in the ascending aorta, the pulmonary trunk, and the right and left pulmonary arteries was determined…

IV: Signifikanztests - wann welchen?

Standard statistics software packages offer a variety of significance tests. The major problem, however, is the correct choice of an appropriate significance test for the underlying data and design setting. In general, the choice of significance tests should decide between two sample versus one sample (i.e. interindividual versus intraindividual) analyses; a further determinant is the clinical endpoint's scale level (mainly continuous or categorical). Two sample comparisons can be performed using the Wilcoxon test for continuous endpoints and the exact Fisher test for binary endpoints. Intraindividual comparisons become feasible using the sign test for continuous and the McNemar test for bi…

Epidemiological evaluation of intraoperative antibiosis as a protective agent against endophthalmitis after cataract surgery.

PURPOSE To evaluate risk factors for endophthalmitis after cataract surgery and to retest recent findings on the protective effect of intraoperative antibiosis and the promoting effect of the clear corneal as compared to sclerocorneal incision. DESIGN Survey study. PARTICIPANTS Five hundred thirty-eight ophthalmosurgical centers in Germany. MAIN OUTCOME MEASURE Responder specific endophthalmitis incidence. RESULTS A total of 310 (58%) questionnaires were computed resulting in an overall count of 404 356 cataract surgeries and 291 self-reported endophthalmitis cases (crude rate 0.072%). The risk of postoperative endophthalmitis for sclerocorneal versus clear corneal incisions was not signifi…

Assessment of left ventricular function by breath-hold cine MR imaging: Comparison of different steady-state free precession sequences

Purpose To compare steady-state free precession (SSFP) sequence protocols with different acquisition times (TA) and temporal resolutions (tRes) due to the implementation of a view sharing technique called shared phases for the assessment of left ventricular (LV) function by breath-hold cine magnetic resonance (MR) imaging. Materials and Methods End-diastolic and end-systolic volumes (EDV, ESV) were measured in contiguous short-axis slices with a thickness of 8 mm acquired in 10 healthy male volunteers. The following true fast imaging with steady-state precession (TrueFISP) sequence protocols were compared: protocol A) internal standard of reference, segmented: tRes 34.5 msec, TA 18 beats pe…

MHC class I antigen processing pathway defects, ras mutations and disease stage in colorectal carcinoma

Colorectal tumorigenesis has been associated with the progressive acquisition of a variety of genetic alterations. These include mutations of the Ki-ras proto-oncogene in codons 12 and 13, which account for 85% of genetic changes in colorectal cancer. In murine in vitro models of oncogenic transformation, an association between ras-mediated transformation and downregulation of different components of the MHC class I antigen processing machinery (APM) has been described. In order to investigate whether this association also exists in human tumors, 10 cases of high-grade intraepithelial neoplasia (HIN), as well as primary tumors and autologous lymph node metastases from 42 patients with color…

A Modification of Stone's Test for Trend for Binary Outcome

STONE (1988) suggested the first isotonic regression estimator as a tool for drawing inferences on possibly increased cancer case counts among several subregions around a putative source. He assumed the case counts to be Poisson distributed and therefore introduced a rare disease assumption into his approach. However, when analyzing cross sectional data one would rather refer to prevalence estimates among these subregions around a point risk source (for example the origin of chemical fallout). Therefore we applied antitonic regression estimation in Binomial distributions to derive a test statistic and a p value to test for a possible trend in the observed prevalence data around the putative…

Optical coherence tomography of macular thickness after biaxial vs coaxial microincision clear corneal cataract surgery

PURPOSE To evaluate macular thickness changes after biaxial microincision versus coaxial small incision cataract surgery using optical coherence tomography (OCT). METHODS This prospective, randomized, marked study comprised 70 patients (70 eyes) undergoing biaxial microincision surgery or conventional coaxial phacoemulsification. Patients were evaluated by Stratus OCT preoperatively and 1 day, 4 weeks, and 8 weeks postoperatively. Best-corrected visual acuity (BCVA), phacoemulsification power, and effective phacoemulsification time (EPT) were evaluated. RESULTS In the biaxial group, median foveal thickness changed from 160 microm preoperatively to 168 microm 8 weeks postoperatively (p=0.018…

Local staging of rectal carcinoma and assessment of the circumferential resection margin with high-resolution MRI using an integrated parallel acquisition technique

Purpose To assess the diagnostic accuracy of integrated parallel acquisition technique (iPAT) in local staging of rectal carcinoma in comparison to conventional high-resolution MRI. Materials and Methods A total of 28 patients with a neoplasm of the rectum and 15 control patients underwent MRI of the pelvis. High-resolution images were acquired conventionally and with iPAT using a modified sensitivity encoding (mSENSE). Image quality, signal-to-noise and contrast-to-noise ratios (SNR, CNR), tumor extent, nodal status, and delineation of the circumferential resection margin (CRM) were compared. In 19 patients with a carcinoma, MR findings were correlated with the histopathological diagnosis.…

VII: Diagnosestudien: Einfache Maße für Validität und Reliabilität

The evaluation of a new diagnostic or imaging device has to focus both on its diagnostic validity and reliability. Cohen's kappa coefficient can be used to assess the agreement of the new device's findings with those of an established diagnostic reference, it therefore presents a surrogate measure of validity. Additional measures of validity are sensitivity and specificity, which assess the order of agreement with the reference for positive and negative reference findings, respectively. The latter, however, can only be applied for binary reference findings. If discordant findings are observed, the McNemar test can be used to detect a diagnostic shift between diagnostic novum and reference. …

III: „Relatives Risiko” und „NNT” - anschauliche Maße für binäre Daten

Description of categorial data can often be based on contingency tables. However, percentages appearing in such tables must be meaningful: For most applications, it may be useful to employ factors of causal influence as the row entry variable and relate percentages to sub-groups defined by these row entries ("row percentages"). The comparison of success frequencies (i. e. binary information on "therapy success yes/no") may be based on two therapies, respective success frequencies and their ratio, the relative risk. In addition the success frequencies' difference, the absolute (or excess) risk, can be transformed into the "number needed to treat" (NNT). Many international journals demand thi…

Volume flow in the common carotid artery does not decrease postprandially.

Background and Purpose. A commonplace explanation for postprandial fatigue is the assumption of the redistribution of perfusion from the cerebral to the mesenterial territory. However, this assumption has never been scientifically proven. Methods. Because approximately 70% of the blood flow in the common carotid artery (CCA) is directed to the internal carotid artery, this vessel can be seen as a major brain-supplying artery. Flow volume in the CCA can be measured by color M-mode duplex sonography. The authors investigated the flow volume rate in 20 healthy volunteers before and after the intake of a high-energy meal. Heart rate, blood pressure, and expiratory CO2 were also measured at both…

Endophthalmitis in cataract surgery

Abstract Objective To document perioperative prophylactic treatment and to evaluate the risk factors for endophthalmitis after cataract surgery. Design Cross-sectional study via anonymous survey. Participants Four hundred sixty-nine centers in Germany were queried. Results A total of 311 (67%) questionnaires were received, with each center reporting an average of 900 cataract surgeries per year (total, 340,633 surgeries in 1996). Respondents reported a total of 267 cases of endophthalmitis, which resulted in a mean responder-specific endophthalmitis rate of 0.148% versus a median rate of 0%. Statistical analysis via Poisson regression suggested that sclerocorneal incisions were associated w…

Refraktiver Nutzen und inkrementelle Kosten der LASIK: Ergebnisse einer Kosten-Nutzen-Studie an zwei universitären LASIK-Zentren

BACKGROUND No data is available to date on the cost effectiveness of laser in situ keratomileusis (LASIK) with regard to the German-speaking health care system. Hence we compared the clinical outcome and cost data of two German LASIK centres in respect of procedure cost effectiveness from the patient perspective. MATERIAL AND METHODS A retrospective cohort study was implemented at the University Hospitals of Mainz and Mannheim. Data on refractive outcome were obtained from the LASIK centres' patient documentation, cost data on the surgery as well as on eyeglasses etc. before and after the surgery were obtained from patient interviews. The primary endpoint of this investigation was the indiv…

Kosteneffektivitätsanalyse der Versorgung von Kataraktpatienten mit monofokalen Intraokularlinsen aus Sicht der Leistungserstatter

BACKGROUND Data on the cost effectiveness of cataract surgery with respect to the German statutory health insurance system are hardly available. Hence the increase in visual acuity as primary efficacy endpoint, order of posterior capsule opacification as primary complication endpoint and direct cost for supplementation with monofocal intraocular lenses have been assessed via meta-analyses to evaluate the procedure's cost effectiveness from the perspective of the German statutory health insurance system. MATERIAL AND METHODS Using the medical internet database MEDLINE two meta-analyses on publications between 1995 and 2002 were carried out, one estimating the gained increase in visual acuity…

Comparison of the sympathetic skin response and continuous wave Doppler sonography of the radial artery.

The value of neurophysiological tests of the autonomic nerve system is limited. One of the clinically most commonly applied test is the skin sudomotor response, frequently referred to as 'sympathetic skin response' (SSR). However, the SSR is a more qualitative than quantitative evaluation technique. Continuous wave (cw) Doppler sonography of the radial artery may be an alternative quantitative approach. We studied 41 age matched volunteers (23 female, 18 male; 16-82 years (mean age 53 years)). The stimulus was a loud and unexpected acoustic signal, alternatively a cough. SSR evaluation included the latency of onset, the duration and the amplitude of the response. Doppler evaluation also inc…

Monocular versus binocular pupillometry.

Purpose To quantify differences between monocular and binocular pupil size measurement under scotopic and mesopic conditions. Setting Department of Ophthalmology, Johannes Gutenberg-University, and Department of Medical Biometry, Epidemiology and Informatics, University of Mainz, Mainz, Germany. Methods Computerized dynamic pupillometry (P2000 SA, Procyon Instruments Ltd.) was used at 3 illumination levels: scotopic at 0.03 lux, mesopic low at 0.82 lux, and mesopic high at 6.4 lux. One hundred forty eyes of 70 healthy volunteers without ocular pathology were examined. The subjects were divided into 2 groups. In the first group, the pupil diameter was measured binocularly first. In the secon…

Brimonidine versus dapiprazole: Influence on pupil size at various illumination levels.

To evaluate the influence of dapiprazole versus brimonidine on pupil size at various illumination levels.Department of Ophthalmology, Johannes Gutenberg-University, Mainz, Germany.In randomized prospective study, 19 healthy volunteers received 2 ophthalmic solutions, dapiprazole and brimonidine, 1 in each eye, for intraindividual comparison. Before and after application, pupil diameter was measured using an infrared binocular pupillometer at 3 illumination levels (0.03, 0.82, and 6.4 lux).Only slight pupil dilation was observed under scotopic conditions after application of both agents. After 20 minutes, the median reduction in pupil width was 1.4 mm for brimonidine and 0.9 mm for dapiprazo…

Case Control Study on Childhood Leukemia in Lower Saxony, Germany

In two municipalities in Lower Saxony statistically valid clusters were observed, which attracted great public interest. Committees were set up to initiate a large variety of on-the-spot-investigations. Finally, it was decided to conduct a case control study throughout Lower Saxony to explore potential risk factors which might explain the observed clusters. A limited number of already established and currently discussed hypotheses was chosen for investigation. The study was based on patients registrated at the German Children's Cancer Registry (GCCR). For each child with leukemia diseased between 1988 and 1993 two population-based controls (local and state controls) and one tumour control w…

Effect of large positioning holes on capsule fixation of plate-haptic intraocular lenses

Abstract Purpose To compare the centration and fixation of silicone plate-haptic intraocular lenses (IOLs) with different-sized positioning holes. Setting Eye Clinic of the Johannes Gutenberg-University Mainz, Mainz, Germany. Methods In a prospective randomized study, 51 Chiroflex C10 and 56 Chiroflex C11 IOLs were implanted under standardized conditions by the same surgeon. The IOL position was documented at the end of surgery and by retroillumination on the first day and 5 months postoperatively. The positioning-hole area was evaluated by ultrasound biomicroscopy (50 MHz) 5 months postoperatively. Results One day postoperatively, no IOL in either group was decentered more than 1.0 mm. Aft…

Retrobulbäre Bestrahlung bei endokriner Orbitopathie - Erfahrungen im Langzeitverlauf

Background Significance of retrobulbar irradiation in patients suffering form Graves' ophthalmopathy, though established since almost one century, is subject of scientific debate. The present study investigated the effect of retrobulbar irradiation using a standardized protocol focussing on long term results. Patients and methods Between 1981 and 1997, 104 patients treated by retrobulbar irradiation (10 to 20 Gray) due to Graves' disease. Twenty-nine of these underwent irradiation as sole treatment (mean follow-up 57 months), while in the remaining 75, it was combined with a systemic steroid treatment (mean follow-up 40 months). Patients were evaluated regarding proptosis, intraocular press…

Reproducibility of optical biometry using partial coherence interferometry: intraobserver and interobserver reliability

Abstract Purpose: To evaluate the intraobserver and interobserver variability in axial length (AL), anterior chamber depth (ACD), and corneal radius measurements using an optical biometry instrument based on partial coherence interferometry (PCI). Setting: Johannes Gutenberg University, Mainz, Germany. Methods: In this observational case series and interobserver reliability trial, 30 healthy, emmetropic to moderately myopic eyes of 15 volunteers were evaluated. The AL, ACD, and corneal radius were measured 20 times in 10 eyes by 1 observer to evaluate the intraobserver variability. To evaluate the interobserver variability, the measurements were taken in 20 eyes by 5 different observers. Me…

Healon5 versus Viscoat during cataract surgery: intraocular pressure, laser flare and corneal changes

Background: The use of a viscoelastic substance facilitates cataract surgery. Healon 5 is a new viscoelastic product with special rheological properties. We evaluated the postoperative effect of Viscoat and Healon5 on intraocular pressure (IOP), central corneal thickness (CCT), endothelial cell counts and laser flare. Methods: Forty-eight eyes of 48 patients undergoing routine phacoemulsification followed by foldable IOL implantation were enrolled. Either Healon5 or Viscoat was used according to a block- randomization scheme. The aspiration technique was standardized. IOP, CCT, endothelial cell counts and laser flare were compared pre- and postoperatively. Statistical analysis was performed…

Anteil des frühen systolischen Flussanstiegs am antegrad fließenden Gesamtvolumen bei Phasenkontrast-Flussmessungen in Atemanhaltetechnik

Purpose To evaluate the contribution of early systole for the assessment of antegrade aortic flow volume by breath-hold velocity-encoded magnetic resonance (MR) flow measurements. Materials and methods Expiratory breath-hold fast low-angle shot (FLASH) phase-contrast flow measurements (temporal resolution tRes 61 msec, shared phases) perpendicular to the proximal ascending aorta and short axis true fast imaging with steady-state precession (TrueFISP) cine MR ventriculometry (tRes 34.5 msec) were performed in ten healthy male volunteers on a 1.5 T MR system (Sonata, Siemens Medical Solutions). Antegrade aortic flow volume (AFV) and left ventricular stroke volume (LV-SV) were evaluated using …

Gesundheitsökonomische Bewertung einer antibiotischen Prophylaxe gegenüber postoperativen Endophthalmitiden

BACKGROUND: Two independent epidemiological studies recently suggested the prophylactic relevance of an intraocular antibiosis against endophthalmitis after cataract surgery. The resulting intervention programme, however, has not only ethical drawbacks, but also has a health economical dimension, which will be focussed in this paper. MATERIAL AND METHODS: A cost analysis is performed to compare the direct costs saved by prevention of endophthalmitis cases and the costs generated by the prophylaxis itself. Furthermore, the clinics' indirect costs due to treatment of unprevented endophthalmitis cases are estimated. RESULTS: The overall gain in direct costs turns out to be about 368 000 Euro p…

Healon5 viscoadaptive formulation: Comparison to Healon and Healon GV

Abstract Purpose To compare the rheological characteristics of a viscoadaptive viscoelastic formulation with those of 2 standard ophthalmic viscosurgical devices (OVDs). Setting Department of Ophthalmology, Johannes Gutenberg-University, and Max Planck-Institute for Polymer Research, Mainz, Germany. Methods An independent comparative study of 3 OVDs of sodium hyaluronate (Healon®, Healon GV®, and Healon®5) was performed using the Advanced Rheometric Expansion System to analyze rheologic behavior (eg, dynamic frequency dependence of the complex viscosity) as well as rheological parameters (eg, viscosity at zero shear rate, pseudoplasticity, relaxation time, elastic and viscous modulus). Resu…

Cumulative incidence rates of the mucopolysaccharidoses in Germany

In order to estimate the cumulative incidence rates of the mucopolysaccharidoses (MPS) in Germany, a retrospective epidemiological survey covering the period between 1980 and 1995 was implemented. Multiple ascertainment sources were used to identify affected patients. A prevalence of approximately 0.69 cases per 100,000 births was obtained for MPS I (Hurler phenotype). Within the study period, 4 patients with Hurler/Scheie phenotype and 7 cases with Scheie disease were detected. The cumulative incidence for MPS II (Hunter syndrome) was estimated as 0.64 cases per 100,000 births (1.3 cases per 100,000 male live births); that for MPS III (Sanfilippo syndrome types A, B and C) as 1.57 cases in…

Outcome Quality Assessment nach LASIK: Ergebnisse einer Benchmark-Studie zu klinischem Ergebnis und Patientenzufriedenheit

Hintergrund Das gesetzlich verankerte klinische Qualitatsmanagement schreibt nicht nur die Prozesskontrolle innerhalb einer Einrichtung vor, sondern impliziert auch die Homogenisierung von Prozessablaufen und vor allem der Ergebnisqualitat zwischen verschiedenen Leistungserbringern. Daher sollten klinisches Ergebnis sowie Kosteneffektivitat der LASIK an den Patienten zweier universitarer LASIK-Zentren im deutschsprachigen Raum gemessen und gegenubergestellt werden.

Ergebnisse der kontrastverstärkten MR-Angiographie der aortoiliakalen Gefäße mit einem 1-molaren Kontrastmittel bei 1,0 T: Vergleich zur i. a. DSA

PURPOSE To evaluate the diagnostic accuracy of contrast-enhanced MR angiography (CE-MRA) using a 1.0 molar contrast agent at 1.0 T for the diagnosis of abdominal aortic aneurysms and stenoses of renal or iliac arteries in comparison to intraarterial digital subtraction angiography (DSA). MATERIALS AND METHODS A total of 19 patients with the suspicion of abdominal aortic aneurysm or stenosis of renal or iliac arteries were examined with CE-MRA at 1.0 T. Intra-arterial DSA served as reference in all cases. After test bolus tracking, 10 or 8 ml of the 1.0 molar contrast agent Gadobutrol corresponding to a dose of 0.1 - 0.15 mmol/kg bw were injected and imaging performed using a FLASH-3D sequen…

Capsule measuring ring to predict capsular bag diameter and follow its course after foldable intraocular lens implantation

Purpose: To evaluate the extent of capsular bag shrinkage after cataract surgery with intraocular lens (IOL) implantation and develop a regression formula to predict postoperative capsular bag size. Setting: Eye Hospital, Johannes Gutenberg-University, Mainz, Germany. Methods: The axial length (AL), anterior chamber depth, and corneal radius in 58 eyes were measured preoperatively. Cataract surgery was by phacoemulsification followed by implantation of a 3-piece, acrylic, posterior chamber IOL. The capsular bag diameter and anterior capsulorhexis were measured intraoperatively and 1 day and 1, 3, and 6 months postoperatively using a Koch capsule measuring ring (HumanOptics). Results: The me…

Assessment of coronary artery bypass grafts: value of different breath-hold MR imaging techniques.

Our aim was to evaluate the patency of coronary artery bypass grafts and to detect graft stenosis using different breath-hold MR imaging techniques.Twenty-two patients with 59 grafts (14 internal mammary artery grafts and 45 saphenous vein grafts) and 76 distal anastomoses (singular and sequential grafts) were studied using a 1.5-T scanner. A two-dimensional T2-weighted breath-hold half-Fourier acquisition single-shot turbo spin echo (HASTE) sequence and a three-dimensional breath-hold contrast-enhanced MR angiography sequence (fast imaging with steady-state free precession) were performed. For MR angiography, a bolus of 20 ml of gadopentetate dimeglumine was used. Time delay for contrast i…

Tightness of duraplasty in rabbits: a comparative study.

OBJECTIVE: The purpose of this study was to test, in rabbits, the tightness of seven dural substitution materials commonly used in neurosurgery, i.e., Lyodura (B. Braun Melsungen AG, Melsungen, Germany), Tutoplast dura (Tutogen Medical, Inc., Parsippany, NJ), Tutoplast fascia lata (Tutogen Medical, Inc.), autologous periosteum, Neuropatch (B. Braun Melsungen AG), Dacron (E.I. du Pont de Nemours and Co., Wilmington, DE), and Ethisorb (Ethicon, Inc., Somerville, NJ). METHODS: Duraplasties were performed with sutures alone or were additionally fixed with fibrin glue. Leakage pressures were assessed by infusion of artificial cerebrospinal fluid, containing sodium fluorescein, into the cisterna …

Lebensqualit�t und Patientenzufriedenheit nach Kataraktchirurgie

Die Messung von Lebensqualitat und Patientenzufriedenheit gewinnt bei der Evaluation von Therapiekonzepten an Bedeutung als erganzendes Effektmas neben dem objektiven klinischen Outcome. Bei "schnell wirksamen" Interventionen wie der Kataraktchirurgie ist jedoch nicht gesichert, ob die klassischen Erhebungsinstrumente, die vor allem fur langsam progredierende und therapierbare Erkrankungen wie das Glaukom konzipiert sind, die Wirkung der Intervention auch hinreichend gut abbilden. Bei 152 konsekutiven Kataraktpatienten wurde neben der Anderung des Visus als objektivem klinischen Effektmas ein eigens fur Kataraktpatienten konzipierter Erhebungsbogen eingesetzt, um die Anderung der Lebensqual…

Diabetes and Peripheral Arterial Occlusive Disease

The purpose of this study was to compare contrast-enhanced three-dimensional MR angiography with conventional digital subtraction angiography (DSA) for identifying and evaluating arteries of the distal calf and foot in diabetic patients with severe arterial occlusive disease who will undergo distal bypass surgery.Twenty-four feet of 24 consecutive patients with diabetes and limb-threatening lower extremity ischemia were prospectively imaged using an ultrafast three-dimensional fast low-angle shot sequence on a 1.5-T MR scanner. All patients also underwent DSA of the diseased extremity within 5 days. Images were interpreted in a randomized manner by two observers in conference. Each lower ex…

Randomised trial of mycophenolate mofetil versus azathioprine for treatment of chronic active Crohn’s disease

BACKGROUNDCrohn’s disease is a chronic inflammatory disease of the alimentary tract. Azathioprine is an effective agent in the management of chronic active Crohn’s disease leading to long term remission of disease activity. Such treatment leads to limited efficacy or side effects in a small subset of patients.AIMSTo compare efficacy and side effects of treatment with azathioprine plus corticosteroids versus mycophenolate mofetil (MMF) plus corticosteroids in patients with chronic active Crohn’s disease.METHODSSeventy patients with chronic active Crohn’s disease (Crohn’s disease activity index (CDAI) greater than 150) were randomised for treatment with azathioprine/cortisone or MMF/cortisone…

Critical assessment of chitotriosidase analysis in the rational laboratory diagnosis of children with Gaucher disease and Niemann-Pick disease type A/B and C.

Laboratory diagnosis of lysosomal storage disorders, especially sphingomyelinase deficiency (Niemann–Pick disease type A/B) and Niemann–Pick disease type C (NPC) can be challenging. We therefore aimed to analyse the feasibility of first-step screening with specific chitotriosidase cut-off values in children ≤ 10 years of age with visceral organomegaly (hepatomegaly, splenomegaly, or hepatosplenomegaly) in whom a storage disorder was suspected. We conducted a retrospective, cross-sectional, referral, single-centre study to assess diagnostic test properties in 106 individuals. Median chitotriosidase activity was 12 655 nmol/h per ml (interquartile range 4693–20982) in Gaucher disease (GD); 78…

Kontrastmittelgestützte 3D-MR-Angiographie der Becken- und Beinarterien mit automatischer Tischverschiebung bei 1,0 Tesla

PURPOSE Assessment of the value of contrast-enhanced MR angiography (ceMRA) using an automatic tracking technique at 1.0 Tesla in comparison with digital subtraction angiography (DSA) of the pelvic and lower limb arteries. MATERIALS AND METHODS In 15 patients with peripheral arterial occlusive disease a ceMRA (3D FLASH, TR/TE = 6.2/2.3 ms, Flip angle alpha = 30 degrees, Matrix 170 x 256) using a new automatic tracking technique was accomplished. The reference method was DSA. Twenty-one vessel segments of each patient were graded as normal, stenosed (> 50%) or occluded. Image material was evaluated independently by two radiologists. RESULTS In comparison, the interobserver agreement showed a…

Nonocclusion and Early Reopening of the Great Saphenous Vein After Endovenous Laser Treatment Is Fluence Dependent

Background. Parameters influencing failure and recanalization rates of endovenous laser treatment (ELT) of the great saphenous vein (GSV) are still to be determined. Objective. To evaluate treatment-related parameters of ELT with respect to early failure of occlusion or recanalization of GSVs. Methods. A series of 77 consecutive patients received ELT of 106 GSVs with continuous pullback of the laser fiber. Duplex examination was performed at 1 day, 4 weeks, and 3 months after the procedure. Clinical patient and vessel characteristics as well as technical parameters of the ELT procedure were evaluated via multiple logistic regression analysis. Results. A median vein length of 60 cm (range of…

Effect of a closed foldable equator ring on capsular bag shrinkage in cataract surgery.

To evaluate the effect of a closed foldable equator ring (CFER) versus a conventional capsular tension ring (CTR) on capsular bag shrinkage.Department of Ophthalmology, Johannes Gutenberg-University, Mainz, Germany.In this prospective study, 70 eyes of 70 patients were randomized to 2 groups using a 1:1 block scheme. After uneventful cataract surgery, a capsular measuring ring was implanted in all eyes to measure the capsular bag diameter in vivo. In Group 1, a CTR was implanted in the capsular bag. In Group 2, a CFER was inserted. Biometric characteristics such as axial length and the horizontal and vertical corneal radii were measured preoperatively. The capsular bag diameter and capsulor…

Subjective photic phenomena with refractive multifocal and monofocal intraocular lenses. results of a multicenter questionnaire.

Abstract Purpose To compare the incidence and severity of photic phenomena after the implantation of the Array® (Allergan) refractive multifocal intraocular lens (MIOL) and a monofocal IOL. Setting Multicenter study at Kiel, Mainz, Karlsruhe, and Bremerhaven, Germany. Methods The study comprised 231 randomly selected patients from 4 study centers. The patients had had uneventful phacoemulsification with implantation of a refractive MIOL (n = 138) or a monofocal IOL (n = 93). By questionnaire, patients were asked whether they experienced light sensations postoperatively (light streaks, halos, flare, flashes, or glare) that had not been noticed preoperatively. Additional questions evaluated w…

V: p-Werte: Was sie besagen und was nicht …

Both an extensive data description and an explicit assessment of a study result's statistical significance should be presented in the result section of a clinical trial report. Whereas the description illustrates the order and clinical relevance of the study findings, the statistical significance describes its generalizability to patients not included in the clinical trial: Despite the random recruitment of patients into a trial, the study results may fail to represent clinical reality (for example the trial might show falsely positive efficacy findings, whereas in "clinical reality" efficacy appears rather limited). A p value measures the statistical significance of a study result -- the s…

Humoral immune responses of lung cancer patients against tumor antigen NY-ESO-1

The cancer-associated antigen NY-ESO-1 is expressed in a number of malignancies of different histological type. Patients with NY-ESO-1 expressing tumors have been shown to bear circulating autoantibodies against this antigen. In this study, we have assessed the NY-ESO-I autoantibody response in patients with lung cancer by a serum ELISA. Using a serum dilution of 1:400 we detected seroreactivity in 35 of 175 (20%) of patients. Incidence of autoantibodies was significantly higher in patients suffering from non small cell lung cancer (NSCLC, 23%) as compared to those with small cell lung cancer (SCLC, 9%). In the NSCLC group, NY-ESO-I antibody was significantly more frequent in patients with …

Efficient Simulation of Multivariate Binomial and Poisson Distributions

Power investigations, for example, in statistical procedures for the assessment of agreement among multiple raters often require the simultaneous simulation of several dependent binomial or Poisson distributions to appropriately model the stochastical dependencies between the raters' results. Regarding the rather large dimensions of the random vectors to be generated and the even larger number of interactions to be introduced into the simulation scenarios to determine all necessary information on their distributions' dependence stucture, one needs efficient and fast algorithms for the simulation of multivariate Poisson and binomial distributions. Therefore two equivalent models for the mult…

Ultrasound-induced blood clot dissolution without a thrombolytic drug is more effective with lower frequencies.

<i>Background and Purpose:</i> Therapeutic ultrasound as stand-alone therapy or in combination with rt-PA has proven to be an effective measure for recanalisation of acute vessel occlusion in different in vitro and in vivo studies. Uncertainty still exists concerning the optimal frequency and intensity with regard to the thrombolytic efficacy of ultrasound. The purpose of this study was a direct comparison of different ultrasound frequencies, when otherwise using identical measurement settings and parameters. <i>Methods:</i> Ultrasound-induced dissolution of fresh human blood clots was studied in a flow system using low-frequency continuous wave ultrasound of 20, 40 …

Pr�fung von Medizinprodukten

Hintergrund. Genau wie Arzneimittel mussen Medizinprodukte vor “Inverkehrbringung” klinisch bewertet werden.Bei der Kenntnisgabe Klinischer Prufungen an Medizinprodukten gegenuber Zertifizierungsbehorden mussen jedoch das inhaltliche Vorgehen sowie die administrative Abwicklung der Prufung am Medizinproduktegesetz (MPG) orientiert sein. Es resultieren mitunter merkliche Abweichungen vom teilweise bekannteren Prozedere bei Studien nach dem Arzneimittelgesetz (AMG). Methode. Summarisch sollen wichtige Abweichungen klinischer Prufungen nach MPG und AMG bei Anmeldung,Durchfuhrung und Kenntnisgabe gegenuber Behorden gegenubergestellt werden. Ergebnisse. Anders als bei Klinischen Prufungen nach d…

Intraocular pressure after small incision cataract surgery: temporal sclerocorneal versus clear corneal incision.

To compare intraocular pressure (IOP) after phacoemulsification and foldable intraocular lens (IOL) implantation using a temporal sclerocorneal or clear corneal incision.Department of Ophthalmology, Johannes Gutenberg-University, Mainz, Germany.One hundred patients (100 eyes) with cataract having phacoemulsification with posterior chamber IOL implantation were randomly assigned to receive a temporal sclerocorneal or clear corneal tunnel incision. Intraocular pressure was measured preoperatively and 6 hours, 1, 2, and 3 days, and 5 months postoperatively. Statistical significance was determined by nonparametric group comparisons using 2-sample random Wilcoxon tests.Six hours postoperatively,…

Ankylosing spondylitis in monozygotic twins: studies on immunological parameters

OBJECTIVE—To examine immunological parameters that might explain disease discordance in monozygotic twin pairs with ankylosing spondylitis (AS). METHODS—11 monozygotic twin pairs (nine with AS, two with undifferentiated spondyloarthropathy) were investigated. The peripheral T cell receptor Vβ repertoire was investigated using FACS analysis and 14 different Vβ antibodies. In addition serum samples were tested for antibodies to Klebsiella pneumoniae, Streptococcus pyogenes, Candida albicans, Proteus mirabilis, and Escherichia coli. Peripheral blood lymphocyte reactivity against a number of bacteria was investigated by interferon γ ELISPOT assays. RESULTS—Twins suffering from AS showed cellula…

Fallzahlplanung in referenzkontrollierten Diagnosestudien

Purpose: A tutorial illustration of a flexible approach to determine the sample size in reference-controlled diagnostic trials. Materials and Methods: Assuming the usual setting of a new diagnostic method to be compared with a reference method, the emphasis is on the sensitivity of the new method in comparison with the reference method, using a binary outcome (positive versus negative) for both methods. Based on the confidence interval of the sensitivity, a simple but flexible procedure for determining the sample size is described, which incorporates clinically interpretable information. The procedure is illustrated by the fictious planning of a trial to assess the diagnostic value of MRI v…

Refraktion, Vorderkammertiefe, Dezentrierung und Tilt nach Implantation monofokaler und multifokaler Silikonlinsen

Hintergrund. Ziel der prospektiven Studie war die Analyse von Refraktion, Vorderkammertiefe, Dezentrierung und Verkippung (Tilt) nach Implantation monofokaler (MONO) und multifokaler (MIOL) Intraokularlinsen (IOL). Patienten und Methode. Bei 103 Augen von 103 Patienten wurde entweder eine dreistuckige monofokale oder multifokale Silikon-IOL implantiert. Vorderkammertiefe (ACD), IOL-Dezentrierung und -Tilt wurden mittels Retroilluminationsfotografie und Scheimpflug-Aufnahmen objektiv quantifiziert. Die Untersuchungen einschlieslich Ermittlung der sujektiven Refraktion wurden praoperativ sowie postoperativ nach 1 Woche und nach 6 Monaten vorgenommen. Ergebnisse. Im Bereich von ±1 dpt um die Z…

Medical Biometry: Statistics or Black Magic?

Graphic representation of data resulting from measurement comparison trials in cataract and refractive surgery.

* BACKGROUND AND OBJECTIVES: The evaluation of new diagnostic measurement devices allows intraindividual comparison with an established standard method. However, reports in journal articles often omit the adequate incorporation of the intraindividual design into the graphic representation. * PATIENTS AND METHODS: This article illustrates the drawbacks and the possible erroneous conclusions caused by this misleading practice in terms of recent method comparison data resulting from axial length measurement in 220 consecutive patients by both applanation ultrasound and partial coherence interferometry. * RESULTS: Graphic representation of such method comparison data should be based on boxplots…

Superior labrum and labral-bicipital complex: MR imaging with pathologic-anatomic and histologic correlation.

The purpose of this study was to analyze the anatomic relationship between the superior labrum, the superior glenoid rim, the superior glenohumeral ligament, and the long head of the biceps tendon.Seventeen cadaveric shoulder specimens underwent axial, oblique coronal, and oblique sagittal MR imaging on a 1.5-T imager. Unenhanced proton density- and T2-weighted spin-echo images with and without fat suppression, and T1-weighted fat-suppressed spin-echo images after intraarticular injection of gadolinium, were obtained of each specimen. The shoulders were then frozen and sectioned into 4-mm-thick slices, either transversely or oblique coronally. After gross anatomic correlation, histologic an…

Fallzahlplanung bei ophthalmologischen Studien*

An essential aspect in the cooperation of clinic and biometry consists in designing of studies, e.g. during the preparation of grant applications or for review by official drug surveillance institutions. A central aspect in study planning is the design-adequate and well-documented prediction of sample size, which should be recommended for any intended study. Based on several examples for sample size planning in study designs, which are of common relevance for ophthalmology, guidelines are derived to enable clinical researchers to perform sample size planning on their own. The latter can be based on the various available software packages for sample size prediction.

Magnetresonanztomographie des Kniegelenks mit einem Niederfeldsystem

Ziel der vorliegenden Untersuchung ist die Evaluierung der Niederfeldmagnetresonanztomographie an einem offenen System unter Berucksichtigung des Erfahrungsstands des Untersuchers. In einer prospektiven Studie wurden von August 1995 bis Mai 1997 75 Patienten der Klinik fur Unfallchirurgie der Universitat Mainz mit einem akuten Trauma des Kniegelenks nach klinischer und konventionell-radiologischer Diagnostik magnetresonanztomographisch untersucht und anschliesend diagnostisch und therapeutisch arthroskopiert. Die Auswertung der MRT-Untersuchungen erfolgte hierbei durch 2 unabhangige Untersucher unterschiedlichen Erfahrungsstands ohne Kenntnis der Anamnese bzw. des klinischen Befunds. Sensit…

Experimentelle In-vitro-Studie zur Evaluierung eines elektronischen Detektors für die digitale Radiographie

Purpose: To evaluate the contrast-detail performance of a flat-panel detector system, we performed a comparative study of this flat-panel system versus storage phosphor and conventional screen-film systems. Materials and Methods: Bone models made of human humeri were prepared with foreign bodies, fracture lines and drilled holes to create artificial fractures, osteolyses or metastases. Immersed in a water bath, hard copy images of these models were acquired with the same exposure dose (55 kV; 3.2 mAs) on the flat-panel detector, two state-of-the-art storage phosphor systems (PCR®, ADC®) and two conventional screen-film systems (Insight®, T-Mat®). Using a standardized protocol with a 4-point…

Mycophenolate mofetil versus azathioprine in patients with chronic active ulcerative colitis: a 12-month pilot study.

Ulcerative colitis (UC) is an inflammatory bowel disease (IBD) of unknown etiology frequently requiring long-term therapy for control of symptoms and prevention of relapse. Azathioprine (AZA) has been shown to be effective and safe in the treatment of chronic active UC. However, the alternatives to treatment with AZA are limited. Our aim was to compare the efficacy and safety of treatment with mycophenolate mofetil (MMF)/prednisolone versus standard immunosuppressive treatment with azathioprine (AZA)/prednisolone in patients with chronic active UC.The study was designed as an open comparison of MMF versus AZA. Twenty-four patients with active UC (Rachmilewitz scoreor =6 points) were randoml…

Systematische Analyse der Geometrie eines definierten Kontrastmittelbolus - Implikationen für die kontrastmittelverstärkte 3D-MR-Angiographie thorakaler Gefäße

Purpose: Little is known about the dispersion of a defined contrast bolus during its passage through the heart and pulmonary vasculature. The purpose of this study was to analyze factors influencing a defined contrast bolus for ce-MRA of thoracic vessels. Materials and Methods: For analysis of bolus geometry, an ECG-gated saturation-recovery Turbo-Flash sequence with a TI of 20 msec was used. It was acquired axially at the level of the pulmonary trunc, so that with one data acquisition a curve analysis was possible in the ascending and descending aorta, and in the pulmonary trunc. Twenty-nine patients received 3 ml of Gd-DTPA diluted with saline to a total of 20 ml. Contrast injection was d…

II: Differenzenplots oder Punktewolken - wann was anwenden?

Sometimes the statistical comparison of diagnostic measurement methods or subsequent measurement series in the same individuals is based on bivariate scattergrams; correlation coefficients and linear regression lines are provided in addition. However, this strategy for data representation must be considered inappropriate, as soon as the measurement series under consideration show the same physical index (e.g. repeated measurement of the intraocular pressure [mm Hg] 2 and 4 weeks after glaucoma surgery). Such data can be handled by computation of the intraindividual difference of an individual's measurement. The resulting series of intraindividual deviations can then be analysed using standa…

Noninvasive assessment of pulmonary hemodynamics in patients with chronic thromboembolic pulmonary hypertension by high temporal resolution phase-contrast MRI: correlation with simultaneous invasive pressure recordings.

Background— Right heart catheterization is the gold standard for assessment of pulmonary hemodynamics in patients with chronic thromboembolic pulmonary hypertension. To date, MRI has not been able to produce precise measurements of mean pulmonary arterial pressure (mPAP). The purpose of the study was to create a model for estimating mPAP and pulmonary vascular resistance in patients with chronic thromboembolic pulmonary hypertension by high temporal resolution phase-contrast MRI (PC-MRI) and to correlate the results with simultaneously acquired, invasive catheter-based measurements (simultaneously measured mPAP) and with right heart catheterization measurements. Methods and Results— A tota…

Assessment of chronic aortic dissection: contribution of different ECG-gated breath-hold MRI techniques.

Our objective was to evaluate the impact of different rapid MRI techniques for the assessment and follow-up of chronic aortic dissections.Fifty-three patients (41 postoperative Stanford type A, 12 type B dissections) were scanned at 1.5 T during a 3-year period. The study reviewed ECG-gated breath-hold black blood sequences and 3D contrast-enhanced MR angiography of the thoracic aorta supplemented by segmented cine and phase-contrast imaging as well as abdominal contrast-enhanced MR angiography. A retrospective separate analysis of black blood acquisitions and contrast-enhanced MR angiograms from a total of 72 examinations was performed by two radiologists to evaluate detection of intimal f…

Objective and subjective evaluation of photic phenomena after monofocal and multifocal intraocular lens implantation11The authors have no commercial or financial interest in any aspect of this study.

Abstract Objective To objectively measure and compare halo, flicker, and glare disability in pseudophakic eyes with monofocal (MONO) and multifocal (MULTI) intraocular lenses (IOLs) with respect to the influence of corneal surface quality, astigmatism, and age. Design Prospective case series. Participants This clinical trial involved 28 eyes of 28 patients after small-incision cataract surgery with a MONO silicone IOL and 28 eyes of 28 patients with zonal-progressive silicone IOL. Intervention A computer program objectively determined halo, glare, and flicker. Corneal surface quality and astigmatism were measured using computerized videokeratography. Ray-tracing analysis was performed based…

The size of Simes’ global test for discrete test statistics

Abstract To increase the power of the Bonferroni–Holm procedure several modified Bonferroni procedures have been proposed (for example, Hochberg, 1988. Biometrika 75, 800–802; Hommel, 1988. Biometrika 75, 383–386), which are based on Simes’ global test (Simes, 1986. Biometrika 73, 751–754). By several simulation studies which, in particular, considered multinormal test statistics, it has been suggested that the Simes test is a level α test. However, an exact proof exists for only few situations one of them assuming independence of test statistics. We studied the behaviour of Simes’ test for discrete test statistics. Due to discreteness one can expect more conservative decisions whereas depe…

Characterization of the interstitial lung and peripheral blood T cell receptor repertoire in cigarette smokers.

T lymphocytes modulate the pulmonary inflammatory response. The aim of this study was to evaluate the clonality within the interstitial lung and peripheral blood T cell receptor (TCR) repertoire in smokers. Interstitial T lymphocytes were isolated from surplus tissue of 16 patients (63 +/- 9 [+/- SD] yr old, 11 male) undergoing surgery due to lung cancer (n = 15) or emphysema. TCR clonality was assessed by PCR amplification followed by spectratyping. Nearly all TCR of interstitial lung lymphocytes showed oligoclonal bands (CD4(+) subset 13/16 patients, 81%; CD8(+) 100%) indicating a specific differentiation. Peripheral blood T lymphocytes (PBL) TCR (especially CD4(+)) had less oligoclonal b…

Substantial Reduction of Platelet Adhesion by Heparin-Coated Stents

Although optimized antiplatelet medication has improved the clinical outcome after coronary stenting, vessel occlusion and restenosis still remain a relevant clinical problem. Platelets play a key role in this process. Therefore, the authors compared the platelet adhesion on different stent surface modifications (electropolished without coating or coated with carbon, carbon and additional heparin, silicon carbide, or heparin alone) to investigate their role in reducing platelet adhesion. All stents and additional stainless steel plates were incubated in heparinized whole blood with radiolabeled platelets. After washing the stents and plates four times, radioactivity caused by the adhesion o…

Beurteilung der Durchgängigkeit von koronaren Bypassgefäßen mit einer 2D T2-gewichteten Turbo-Spin-Echo-Sequenz (HASTE) in Atemanhaltetechnik

AIM To evaluate the patency of coronary artery bypass grafts with a 2D T2-weighted breath-hold turbo-spin-echo sequence. METHODS 38 patients with 97 grafts (19 internal mammary artery and 78 saphenous vein grafts) and a total of 120 distal anastomoses were studied at 1.5 Tesla in supine position using a phased array body coil. An ECG gated 2D T2-weighted breath-hold turbo-spin-echo sequence (HASTE) was performed. Reference method was selective coronary angiography. The image material was evaluated independently by two radiologists (observer one, a radiological fellow and the second a staff radiologist). RESULTS Observer 1 reached a sensitivity of 96% (72/75) and a specificity of 91% (20/22)…

Capsular bag shrinkage after implantation of a capsular bending or capsular tension ring.

To evaluate the influence of a capsular bending ring (CBR) or tension ring (CTR) on capsular bag shrinkage.Department of Ophthalmology, Johannes Gutenberg-University, and Department of Medical Biometry, Epidemiology and Informatics, University of Mainz, Mainz, Germany.In 92 eyes of 92 patients, a capsular measuring ring (CMR) was implanted after phacoemulsification to measure capsular bag size in vivo. Patients were randomized into 3 groups: The first received a CMR and CBR, the second received a CMR and CTR, and the third received a CMR alone. Measurements were performed preoperatively, intraoperatively, during the first 3 postoperative days, and after 1 and 3 months. Preoperative biometri…

Is Homelessness a Risk Factor for Eye Disease?

<i>Background:</i> There is general agreement on the presence of a correlation between poverty and impaired health. However, only scarce data are available on whether this also applies to the incidence of eye disease. The present study was carried out to evaluate the prevalence of ocular disease in homeless people in Germany. <i>Methods:</i> 107 homeless people (97 male, 10 female; mean age 49 years, range 18–81 years) treated in specialised social service institutions were investigated prospectively according to a standardised ophthalmological screening protocol. This comprised visual acuity, assessment of pupillary light reaction, intra-ocular pressure, slit lamp e…

Reliability and validity of the Digigraph 100 in orthodontic diagnosis.

Cephalometric analyses of lateral cephalograms allow important statements to be made on diagnosis and treatment planning. Such radiographs should, however, be taken with a considerable reduction in radiation exposure. With the Digigraph 100 (Dolphin Imaging Systems Inc., USA) a cephalometric technique based on distance measurements of emitted sonic signals is now available. This study was aimed at determining the degree to which this procedure can cope with the requirements of reliability and validity in the field of orthodontics. For this purpose 50 volunteers were examined by conventional cephalometry with manual tracing of lateral cephalograms as well as by sonic cephalometry, with Jarab…

I: Boxplots - die flexible Alternative zum „Antennenbildchen”

Data description for continuous parameters is sometimes only based on means and standard deviations of measurement series, graphical representation only concentrates on corresponding "MSE plots", which provide means and standard deviations or even only mean squared errors. However, this strategy is only correct for normally distributed data. Outliers may seriously bias mean and standard deviations and may therefore lead to wrong clinical conclusions. The present paper suggests the use of medians and quartiles, which - just like their graphical pendant, the nonparametric "box whisker plot" - can be applied much more flexibly.

VI: Konfidenzintervalle - die Alternative zum p-Wert

Confidence intervals combine the ideas of clinical relevance and statistical significance by using one instructive expression, which enables remarkable reduction of table structures and result sections in scientific publications. Confidence interval based conclusions can be transferred from a clinical trial to its underlying study population with respect to a residual statistical error probability, i.e. the significance concept is retained. However, their presentation using the original unit of the clinical endpoint under consideration allows for immediate interpretation of the results' clinical impact. For example, the comparison of two therapy groups based on a binary endpoint becomes fea…

Comparison of biometric measurements using partial coherence interferometry and applanation ultrasound

Abstract Purpose To compare and contrast axial length (AL) measurements assessed by ultrasound biometry and optical biometry. Setting Department of Ophthalmology, Johannes Gutenberg-University, Mainz, Germany. Methods Optical biometry and ultrasound biometry were performed in 360 eyes to measure AL. Results In eyes with a clear-appearing crystalline lens, there was a statistically significant median difference in AL measurements between the 2 methods in eyes with a normal or long length. In eyes with cataract, there was a statistically significant median difference in AL measurements in eyes with a normal or short length. In these cases, optical biometry produced larger readings than ultras…

Inhaled iloprost in patients with chronic thromboembolic pulmonary hypertension: effects before and after pulmonary thromboendarterectomy.

Abstract Background In primary pulmonary hypertension, aerosolized prostanoids selectively reduce pulmonary vascular resistance and improve right ventricular function. In this study, hemodynamic effects of inhaled iloprost, a stable prostacyclin analogue, were evaluated in patients with chronic thromboembolic pulmonary hypertension (CTEPH) before and early after pulmonary thromboendarterctomy (PTE). Methods Ten patients (mean age 49 years old [32 to 70 years old], New York Heart Association functional class III and IV) received a dose of 33 μg aerosolized iloprost immediately before surgery (T1), after intensive care unit admission (T2), and 12-hours postoperatively (T3). Effects on pulmona…

Case Control Study of Neuroblastoma in West-Germany after the Chernobyl Accident

Background To explore possible causes of a 1988 incidence peak of infant neuroblastoma in west German regions which were contaminated with more than 6000 Bq/m2 Cs137 from the Chernobyl accident. The primary working hypothesis was that parents of the diseased children had been contaminated by an excessive intake of locally produced food, especially mushrooms or deer. Design Case control study with 1:2 (cases:controls) matching. Data were collected from the children's parents by questionnaires and telephone interviews. Setting Nation-wide study (former FRG) based on the German Childhood Cancer Registry. Subjects Cases born in 1988 and reported with a neuroblastoma to the registry until March …

Evaluation of the practicality of optical biometry and applanation ultrasound in 253 eyes

Abstract Purpose To evaluate the percentage of eyes that could not be measured using optical biometry and ultrasound applanation and the reasons. Setting Department of Ophthalmology, Johannes Gutenberg-University Hospital, Mainz, Germany. Methods Optical biometry (IOLMaster®, Carl Zeiss Meditec AG) and A-scan ultrasound biometry were performed consecutively in 253 eyes scheduled for cataract surgery the next day. Lens opacities were evaluated with the Opacity Lensmeter (Interzeag), and a slitlamp examination and measurement of visual acuity were performed. The 2 techniques were compared in terms of the rate of and reasons for primary measurement failure. Results Measurement with the IOLMast…

No primary association between LMP2 polymorphisms and extraspinal manifestations in spondyloarthropathies

OBJECTIVE—To investigate the potential role of the HLA-linked LMP2 (low molecular weight protein) gene polymorphisms in conjunction with DR4 and DR7 on extraspinal disease manifestations in HLA-B27 positive patients with spondyloarthropathy.
METHODS—172 patients with spondyloarthropathy, 46 healthy, HLA-B27 positive blood donors, and 99 unrelated controls were typed for HLA-class I and II antigens. LMP2 alleles were determined by polymerase chain reaction and subsequent restriction enzyme digestion.
RESULTS—There were statistically non-significant increases of DR4 and DR7 in spondyloarthropathy subjects. However these differences did not relate to specific extraspinal manifestations. There …

Inflammation after sclerocorneal versus clear corneal tunnel phacoemulsification.

Abstract Objective To compare the postoperative inflammation after phacoemulsification followed by intraocular lens (IOL) implantation by means of sclerocorneal versus clear corneal tunnel incision. Design Randomized controlled clinical trial. Participants One hundred eyes of 100 patients were examined at a German University eye hospital. Intervention One hundred eyes with cataract necessitating phacoemulsification with posterior chamber IOL implantation were randomly assigned to receive a temporal sclerocorneal or clear corneal tunnel incision by a single surgeon. Main outcome measures Preoperative and postoperative inflammation was evaluated by measurement of flare using laser flare photo…

Improvements and Modifications of Tarone's Multiple Test Procedure for Discrete Data

Tarone (1990, Biometrics 46, 515-522) proposed a multiple test procedure for discrete test statistics improving the usual Bonferroni procedure. However, Tarone's procedure is not monotone depending on the predetermined multiple level a. Roth (1998, Journal of Statistical Planning and Inference, in press) developed a monotone version of Tarone's procedure. We present a similar procedure that is both monotone and an improvement of Tarone's proposal. Based on this extension, we derive a step-down procedure that is a corresponding improvement of Holm's (1979, Scandinavian Journal of Statistics 6, 65-70) sequentially rejective procedure. It is shown how adjusted p-values can be computed for the …

Biaxial Microincision versus Coaxial Small-Incision Clear Cornea Cataract Surgery

Objective To compare clinical outcomes of biaxial microincision (1.5 mm) and coaxial small-incision (2.75 mm) clear cornea cataract surgery. Design Randomized controlled clinical trial. Participants Seventy eyes of 70 patients were examined at a German university eye hospital. Intervention The 70 patients (70 eyes) were assigned randomly (1:1) to a biaxial or conventional coaxial incision group. Both groups underwent phacoemulsification using pulsed ultrasound energy with variable duty cycles, followed by microincision intraocular lens implantation. Main Outcome Measures Best-corrected visual acuity (BCVA), astigmatism, laser flare photometry value, effective phacoemulsification time (EPT),…

Blood flow velocity waveforms of the fetal middle cerebral artery in a normal population: reference values from 18 weeks to 42 weeks of gestation

The aim of this prospective cross-sectional study was to establish new Doppler reference curves for peak blood flow velocities (Vmax, Vmean, Vmin) and impedance indices (PI, RI) of the middle cerebral artery at 18-42 weeks of gestation by an automatic wave form analysis integrated into the ultrasound device. In 962 low-risk pregnancies, blood flow velocities were derived from the middle cerebral artery with pulsed color Doppler ultrasonography. Reference curves were constructed for the individual parameters based on a growth function from a four-parameter class of monotonic continuous functions according to the smallest square principle for maximum blood flow velocities, as well as on a pol…

VIII: Statistik in klinischen Publikationen: Checklisten für Autoren

The "Material and Methods" section of clinical research papers should reference major aspects concerning statistical planning and evaluation of the study design and the resulting clinical data. Particular focus is laid on the listing of methods for description and significance evaluation of the trial data, as well as on design-associated study determinants (randomisation and masking strategy, response rate evaluation, primary endpoints, power and sample size determination, multiple testing, software and methods for statistical analysis). Suggestions for the minimum content to be mentioned in a trial publication are listed in author check lists and are illustrated by means of the study synop…

Assessment of Thoracic Aortic Dimensions in an Experimental Setting: Comparison of Different Unenhanced Magnetic Resonance Angiography Techniques With Electrocardiogram-Gated Computed Tomography Angiography for Possible Application in the Pediatric Population

PURPOSE To compare different unenhanced magnetic resonance angiography (MRA) techniques for quantitative evaluation of vessel lumen in an experimental setting in young pigs whose dimensions allow for a comparison with a pediatric population. MATERIAL AND METHODS Magnetic resonance imaging was performed in 5 healthy ventilated pigs at 1.5 T. Three different electrocardiogram (ECG)-triggered sequences were applied for MRA: [TSE-Db] T2-weighted dark-blood TurboSpinEcho (2.0 x 1.1 x 4 mm3); [trueFISP] 2D-steady-state-free-precession (2.2 x 1.8 x 2 mm3); [NAV] respiratory-gated, T2-prepared 3D-trueFISP (1.3 x 1.3 x 1.3 mm3). ECG-gated-CT angiography (CTA) (16-row CT, 1 mm collimation) served as …

Statistical methods for the comparison of measurements derived from orthodontic imaging

Biometric comparison procedures for dental imaging methods with continuous outcome were reviewed, mainly concentrating on assessment and comparison of accuracy and precision according to the study design. Univariate graphical and numerical representations of corresponding deviations were summarized to derive a 'check list' of minimum information necessary to compare the measurement methods. The methods reviewed in this investigation are illustrated by the comparison of conventional (radiographic) cephalometry versus assessment using the DigiGraph in 50 female children. A paired t-test and the corresponding confidence interval approach were used to assess deviations in location of two imagin…

Chronic Thromboembolic Pulmonary Hypertension: Pre- and Postoperative Assessment with Breath-hold MR Imaging Techniques

To evaluate the potential of breath-hold magnetic resonance (MR) imaging techniques in morphologic and functional assessment of patients with chronic thromboembolic pulmonary hypertension (CTEPH) before and after surgery.Thirty-four patients with CTEPH were examined before and after pulmonary thromboendarterectomy (PTE). For morphologic assessment, contrast material-enhanced MR angiography was used; for assessment of hemodynamics, velocity-encoded gradient-echo sequences and cine gradient-echo sequences along the short axis of the heart were performed. Contrast-enhanced MR angiography was compared with selective digital subtraction angiography (DSA) for depiction of central thromboembolic m…

Niederfeld-MR-Tomographie des Kniegelenkes: Ergebnisse einer prospektiven, arthroskopisch kontrollierten Studie

PURPOSE To define the diagnostic accuracy of an open low-field MR unit (Magnetom Open, Siemens, Erlangen) in traumatic knee lesions. MATERIALS AND METHODS The MRIs of 150 patients were prospectively evaluated by two independent readers with different experience levels. The study protocol included a proton-density weighted SE-sequence in the sagittal, a T2.-weighted Flash-2D-sequence in the coronal, and a 3D-acquisition (DESS) in the axial plane. 75 patients were treated either conservatively or operatively. RESULTS Based on arthroscopy as the gold standard, the sensitivities, specificities, and diagnostic accuracies for lesions of the medial and lateral meniscus, the anterior cruciate ligam…

Locked Plate Fixation and Intramedullary Nailing for Proximal Humerus Fractures: A Biomechanical Evaluation

Background Internal fixation of proximal humeral fractures is associated with a considerable secondary malalignment rate. Fixed-angle implants have been suggested to increase the stability of fixation. Methods The biomechanical properties of four different implants were tested. These included an internal fixator with semi-elastic properties (reference), the Synthes T-plate, a locked plate with rigid properties and a spiral blade locked intramedullary nail (PHN). These implants were assessed in twenty-four osteotomized pairs of human cadaveric humeri. Specimens were subjected to two-hundred cycles of axial loading and torque followed by load to failure. Results The PHN had greater axial stif…

Contrast sensitivity after implantation of a spherical versus an aspherical intraocular lens in biaxial microincision cataract surgery.

Purpose To determine whether implantation of a microincision intraocular lens (IOL) with a modified anterior surface, designed to compensate for the positive spherical aberration of the cornea in eyes of cataract patients, results in improved pseudophakic quality of vision in pseudophakic eyes after biaxial microincision phacoemulsification. Setting Department of Ophthalmology, Johannes Gutenberg-University, Mainz, Germany. Methods In a nonrandomized parallel cohort investigation, the visual performance of 52 eyes of 52 patients unilaterally implanted with the aspherical Acri.Smart 36 A IOL (Acri.Tec) were compared with those of 25 eyes of 25 age-matched patients unilaterally implanted with…

The comparison of reliabilities in dental imaging methods.

Objectives: Common practice in the statistical comparison of imaging instruments with limited reproducibility consists in the separate estimation of the instrument's reliabilities. However, as soon as one of the imaging methods is subject to item-specific bias (which has to be expected in many dentomaxillofacial imaging procedures), this approach will end in severe errors in reliability computation and in corresponding erroneous clinical conclusions. This paper seeks to point out these effects and to illustrate a more appropriate model for the comparison of instrumental reliabilities. Methods: A standard reliability model was adjusted for item-specific bias and illustrated by the comparison…