CAT score single item analysis in patients with COPD: results from COSYCONET

Abstract The COPD Assessment Test (CAT) is in widespread use for the evaluation of patients with chronic obstructive pulmonary disease (COPD). We assessed whether the CAT items carry additional information beyond the sum score regarding COPD characteristics including emphysema. Patients of GOLD grades 1 to 4 from the COPD cohort COSYCONET (German COPD and Systemic Consequences - Comorbidities Network) with complete CAT data were included (n = 2270), of whom 493 had chest CT evaluated for the presence of emphysema. Comorbidities and lung function were assessed following standardised procedures. Cross-sectional data analysis was based on multiple regression analysis of the single CAT items ag…

Quantification and Characterization of Pulmonary Emphysema in Multislice-CT

The new technology of the Multislice-CT provides volume data sets with approximately isotropic resolution, which permits a non invasive measurement of diffuse lung diseases like emphysema in the 3D space. The aim of our project is the development of a full automatic 3D CAD (Computer Aided Diagnosis) software tool for detection, quantification and characterization of emphysema in a thoracic CT data set. It should supply independently an analysis of an image data set to support the physician in clinical daily routine. In this paper we describe the developed 3D algorithms for the segmentation of the tracheo-bronchial tree, the lungs and the emphysema regions. We present different emphysema des…

Contrast-Enhanced Magnetic Resonance Angiography of the Pulmonary Vasculature

Magnetic resonance angiography (MRA) has been established as a powerful noninvasive imaging modality. Its applications to the study of the pulmonary vasculature have been hampered by a multitude of factors, such as respiratory and cardiac motion artifacts, saturation problems, long acquisition times

Fokussuche bei neutropenischem Fieber

The German COPD cohort COSYCONET: Aims, methods and descriptive analysis of the study population at baseline

Abstract Background The German COPD cohort study COSYCONET (" CO PD and SY stemic consequences- CO morbidities NET work") investigates the interaction of lung disease, comorbidities and systemic inflammation. Recruitment took place from 2010 to 2013 in 31 study centers. In addition to the baseline visit, follow-up visits are scheduled at 6, 18, 36 and 54 months after baseline. The study also comprises a biobank, image bank, and includes health economic data. Here we describe the study design of COSYCONET and present baseline data of our COPD cohort. Methods Inclusion criteria were broad in order to cover a wide range of patterns of the disease. In each visit, patients undergo a large panel …

Functional Evaluation of Emphysema Using Diffusion-Weighted 3Helium-Magnetic Resonance Imaging, High-Resolution Computed Tomography, and Lung Function Tests

Purpose: To assess the emphysematous enlargement of distal air-spaces and concomitant large and small airway disease using diffusion-weighted 3 Helium-magnetic resonance imaging (MRI), high-resolution computed tomography (HRCT), and lung function tests (LFT). Methods: Seven patients were examined after single lung transplantation (LTx) and 1 before double LTx for various forms of emphysema. Five patients after double LTx served as controls. Patients were assessed by 3 Helium-MRI (apparent diffusion coefficient [ADC]), HRCT (mean lung density [MLD], emphysema index [El]), and LFT. Results: Transplanted lungs: mean ADC = 0.17 cm 2 /s, MLD = -848 H, El = 22%. Emphysematous lungs: mean ADC = 0.…

A phase I study of adenovirus-mediated wild-type p53 gene transfer in patients with advanced non-small cell lung cancer.

Mutations of the tumor suppressor gene p53 are the most common genetic alterations observed in human cancer. Loss of wild-type p53 function impairs cell cycle arrest as well as repair mechanisms involved in response to DNA damage. Further, apoptotic pathways as induced by radio- or chemotherapy are also abrogated. Gene transfer of wild-type p53 was shown to reverse these deficiencies and to induce apoptosis in vitro and in preclinical in vivo tumor models. A phase I dose escalation study of a single intratumoral injection of a replication-defective adenoviral expression vector encoding wild-type p53 was carried out in patients with incurable non-small cell lung cancer. All patients enrolled…

Hyperpolarized helium-3 gas magnetic resonance imaging of the lung.

3He magnetic resonance imaging (MRI) is capable of producing new and regional information on normal and abnormal lung ventilation. The basis of 3He MRI involves "optical pumping" to hyperpolarize the 3He nuclei by photon angular momentum transfer. The hyperpolarized gas is administered via inhalation. 3He is an inert, nontoxic noble gas and absorbed in less than 0.1%. Imaging consists of a four-step protocol. 1) Gas density 3He MRI with high spatial resolution displays the distribution of a 3He bolus in a 10-second breath-hold. An almost homogeneous distribution is regarded as normal. Patients with lung diseases show multiple ventilation defects. 3He MRI has been shown to be more sensitive …

Recommendations of the Thoracic Imaging Section of the German Radiological Society for clinical application of chest imaging and structured CT reporting in the COVID-19 pandemic.

This information provided by the Thoracic Imaging Section of the German Radiological Society is intended to give physicians recommendations on the use of thoracic imaging procedures in the context of the current COVID-19 pandemic. It represents the consensus of the authors based on the previous scientific knowledge and is intended to provide guidance for unified, structured CT reporting if COVID-19 pneumonia is suspected. The recommendations presented correspond to state of knowledge at the time of print and will be updated according to the results of ongoing and future scientific studies. KEY POINTS:: · COVID-19. · chest imaging. · German Radiological Society. CITATION FORMAT: · Vogel-Clau…

Bronchiektasen und Infekthäufigkeit bei Alpha-1-Antitrypsin-Mangel

UNLABELLED PURPOSE of this study was to determine the prevalence of bronchiectasis in patients suffering from alpha-1-antitrypsin deficiency and to compare its extent with the frequency of infections. MATERIAL AND METHODS High-resolution CT examinations (HRCT) of 23 patients with alpha-1-antitrypsin deficiency were retrospectively assessed for extent, severity and localisation of bronchiectasis, bronchial wall thickening and extent of emphysema. Chest radiographs and clinical records were available for correlation. RESULTS HRCT scans showed bronchiectasis in 14 of 23 patients, bronchial wall thickening in 3/14, and panlobular emphysema in 23/23. Chest radiographs showed bronchiectasis in 4/…

Imaging of the lungs using 3he MRI: Preliminary clinical experience in 18 patients with and without lung disease

The purpose of this study was to describe the 3He MRI findings of normal pulmonary ventilation in healthy volunteers and to evaluate abnormalities in patients with different lung diseases. Hyperpolarized 3He gas (300 ml, 3 x 10(5) Pa, polarized to 35-45% by optical pumping, provided in special glass cells) was inhaled by 8 healthy volunteers and 10 patients with different lung diseases. Imaging was performed with a three-dimensional fast low-angle shot (FLASH) sequence (TR = 11.8 msec; TE = 5 msec; transmitter amplitude, 5-8 V; corresponding flip angle, < 5 degrees) in a single breath-hold (22-42 seconds). Clinical and radiological examinations were available for correlation. The studies we…

Spiral-Computertomographie der Mamma

Aim To evaluate the use of spiral CT in the diagnosis of breast lesions. Material and methods 93 female patients with suspicious or uncertain mammographic findings were examined by CT before and after contrast enhancement according to the following practical method: table movement, 6 mm/s, slice thickness 6 mm, increment 4 mm, contrast 200 ml, injection rate 3 ml/s, scan start 50 s after the beginning of the injection. Histological confirmation was present in 85 patients. Results All 44 invasive carcinomas were recognised. They were characterised by intensive focal contrast uptake. Only 2 out of 7 intraductal carcinomas were not shown by CT. 36 out of 38 benign lesions were correctly diagno…

Elucidation of structure-function relationships in the lung: contributions from hyperpolarized 3 helium MRI

Magnetic resonance imaging (MRI) using hyperpolarized 3helium (He) gas as the source of signal provides new physiological insights into the structure-function relationships of the lung. Traditionally, lung morphology has been visualized by chest radiography and computed tomography, whereas lung function was assessed by using nuclear medicine. As all these techniques rely on ionizing radiation, MRI has some inherent advantages. 3He MRI is based on 'optical pumping' of the 3He gas which increases the nuclear spin polarization by four to five orders of magnitude translating into a massive gain in signal. Hyperpolarized 3He gas is administered as an inhaled 'contrast agent' and allows for selec…

3He-MRI-based measurements of intrapulmonarypO2 and its time course during apnea in healthy volunteers: first results, reproducibility, and technical limitations

We applied a recently developed method of following the time course of the intrapulmonary oxygen partial pressure p(O2)(t) during apnea by (3)He MRI to healthy volunteers. Using two imaging series with different interscan times during two breathholds (double acquisition technique), relaxation of (3)He due to paramagnetic oxygen and depolarization by RF pulses were discriminated. In all four subjects, the temporal evolution of p(O2) was found to be linear, and was described by an initial partial pressure p(0) and a decrease rate R. Also, regional differences of both p(0) and R were observed. A correlation between p(0) and R was apparent. Finally, we discuss limitations of the double acquisit…

Intrapulmonary 3He Gas Distribution Depending on Bolus Size and Temporal Bolus Placement

OBJECTIVE: Dynamic ventilation (3)He-MRI is a new method to assess pulmonary gas inflow. As differing airway diameters throughout the ventilatory cycle can influence gas inflow this study intends to investigate the influence of volume and timing of a He gas bolus with respect to the beginning of the tidal volume on inspiratory gas distribution. MATERIALS AND METHODS: An ultrafast 2-dimensional spoiled gradient echo sequence (temporal resolution 100 milliseconds) was used for dynamic ventilation (3)He-MRI of 11 anesthetized and mechanically ventilated pigs. The applied (3)He gas bolus was varied in volume between 100 and 200 mL. A 150-mL bolus was varied in its application time after the beg…

3D TOF MR Angiography of Cerebral Arteriovenous Malformations after Radiosurgery

To investigate the potential of three-dimensional time-of-flight MR angiography (MRA) to complement SE imaging, 18 patients with intracerebral arteriovenous malformations were prospectively followed after undergoing radiosurgery. Vessel occlusion after stereotaxic single high dose radiotherapy develops slowly. The MRA detected signs of nidus obliteration earlier and with a higher sensitivity than did SE imaging. Six months after radiosurgery, MRA showed a reduction of the nidus flow signals in nine patients and after 1 year it showed reduction in 15 of the 18 patients. As shown by MRA, the loss of flow signals was related to a reduction of the nidus size in 4 patients after 6 months and in …

Pulmonale Struktur und Funktion - Hochauflösende und dynamische Computertomographie bei Lungenemphysem und Erkrankungen der Atemwege -

Computed tomography (CT) is the method of choice for the morphological assessment of pulmonary structure. Airways. pulmonary parenchyma and their pathologies are shown with high spatial resolution. Airway diseases exhibit bronchial dilatation, wall thickening and an increased visibility in the lung periphery. CT is also the imaging gold standard for the detection and the characterisation of emphysema because a high degree of concordance with histopathological studies. Centrilobular, panlobular and paraseptal emphysema can be differentiated. CT can also provide functional information. Paired inspiratory and expiratory scans with or without spirometric triggering allow to evaluate obstruction…

Pulmonale Manifestationen bei HIV-Patienten: Rolle von Thoraxübersicht, CT und HRCT

Aim To determine the prevalence of pulmonary changes on chest radiographs and computed tomography (CT/HRCT) in HIV patients and their relation to pulmonary symptoms. Material and method 64 HIV patients were examined prospectively. 15 had no respiratory symptoms (group I), 30 had non-specific respiratory symptoms (group II), 19 complained of dyspnoea (group III). Chest radiographs and CT were performed within a week. In patients with positive findings, bronchoscopy was carried out with bacteriological and histological examinations. Results In group 1, 13% of chest radiographs and 40% of CTs showed infiltrative changes. In group II, the figures were 27% and 57% respectively. In group III, abn…

Analysis of discrete and continuous distributions of ventilatory time constants from dynamic computed tomography.

In this study, an algorithm was developed to measure the distribution of pulmonary time constants (TCs) from dynamic computed tomography (CT) data sets during a sudden airway pressure step up. Simulations with synthetic data were performed to test the methodology as well as the influence of experimental noise. Furthermore the algorithm was applied to in vivo data. In five pigs sudden changes in airway pressure were imposed during dynamic CT acquisition in healthy lungs and in a saline lavage ARDS model. The fractional gas content in the imaged slice (FGC) was calculated by density measurements for each CT image. Temporal variations of the FGC were analysed assuming a model with a continuous…

CT after enucleation of renal cell carcinoma.

Computed tomography (CT) was performed in 28 patients 2 weeks to 120 months after enucleation of renal cell carcinoma. The postoperative defect could be exactly localized in all patients. A wedge-shaped (N = 11) or concave (N = 9) morphology was typical. No dependence between morphology of the defect and localization or size of the tumor or the operative technique was observed. The defects were smaller (1.9 cm) than the original prominent tumors (3.6 cm). Defect size was dependent on the operative technique: closure by suture of the renal capsule in smaller defects or by fat flap in larger ones. Postoperative hematomas or delayed perfusion in the adjacent parenchyma were seen in five patien…

Assessment of pulmonary hypertension by CT and MR imaging.

In the recent World Health Organization (WHO) classification the group of pulmonary arterial hypertension (PH) comprises the classic primary pulmonary hypertension and several conditions with definite or very high risk factors to develop pulmonary arterial hypertension. Therapeutic advances drive the need for a comprehensive pre-therapeutic evaluation for optimal treatment. Furthermore, follow-up examinations need to be performed to monitor changes in disease status and response to therapy. Up to now, the diagnostic imaging work-up of PH comprises mainly echocardiography, invasive right heart catheterization and ventilation/perfusion scintigraphy. Due to technical advances helical computed …

Flip angle considerations in (3)helium-MRI.

3Helium-MRI ((3)He-MRI) can be used for analysis of lung function, e. g. dynamic imaging of ventilation and gas diffusion within the lung, assessment of intrapulmonary oxygen concentrations and their time course. During imaging, the irreversible signal loss due to depolarizing radio frequency excitations can be described using the flip angle (FA) alpha. This parameter has to be quantified in order to account for it during quantitative assessment of the (3)helium signal intensity and its temporal development. This technical report reviews two different methods to determine alpha. Limitations and possible error sources of each method are discussed.

Early detection of pneumonia in febrile neutropenic patients: use of thin-section CT.

The purpose of this study was to evaluate the usefulness of thin-section CT for early detection of pneumonia in neutropenic patients with an unknown site of infection and normal or nonspecific findings on chest radiographs.Eighty-seven patients with febrile neutropenia that persisted for more than 2 days despite empiric antibiotic treatment underwent 146 prospective examinations. If findings on chest radiographs were normal (n = 126) or nonspecific (n = 20), thin-section CT (1-mm collimation, 10-mm increment) was done. If thin-section CT scans showed opacities, bronchoalveolar lavage was recommended.Findings on chest radiographs were nonspecific for pneumonia in 20 (14%) of 146 cases, and C…

Volumetry of Ventilated Airspaces by 3He MRI

To develop a validated post-processing routine for volumetry of the ventilated airspaces by 3He MRI.3Helium MRI and pulmonary function tests were performed in seven healthy volunteers. After segmentation of ventilated airspaces, their volumes were calculated. Functional residual capacity (FRC) was used as a reference. For comparison of absolute volumes, correction factors were evaluated.Mean lung volume (+/- standard deviation) calculated from 3He MRI was 4,082 +/- 908 mL and mean FRC was 3,696 +/- 1166 mL, with a mean difference of 386 mL (r = 0.88). After correction for the relative pulmonary air content (factor 0.82), posture (0.72), and the individual tidal volume, 3He MRI volume was 3,…

Helical computed tomographyangiography: Technical considerations and clinical applications

Abstract A combination of volume acquisition techniques (helical CT), dedicated protocolsfor bolus injections of contrast medium, and postprocessing modalities have paved the way for computed tomography (CT) angiography. To obtain optimum results the collimation must be adapted to the vascular territory of interest, and the reconstruction of overlapping source images from the volume data set is advantageous for further postprocessing. Strong intravascular opacification is indispensable for the evaluation of vascular abnormalities and pathology and is also helpful for image postprocessing, where different modalities can be applied: multiplanar reconstruction, maximum intensity projection, se…

Surgical treatment of pulmonary artery sarcoma

Abstract Objective: Pulmonary artery sarcomas are rare and usually fatal tumors. The diagnosis is difficult and delayed in most cases. Newer imaging techniques could allow early diagnosis in patients with symptoms of pulmonary vascular obstruction. Surgical resection improves clinical symptoms and offers the only chance of cure. We report the case histories of 7 patients with primary pulmonary artery sarcomas treated by surgical resection with or without adjuvant therapy. Methods: Seven patients (3 women and 4 men; mean age, 52.3 years; preoperative New York Heart Association functional class III/IV, n=5/2) underwent operations. Malignancy was preoperatively suspected in 5 patients, and 2 p…

Value of contrast-enhanced MR angiography and helical CT angiography in chronic thromboembolic pulmonary hypertension.

The aim of this study was to evaluate the diagnostic value of contrast-enhanced MR angiography (ce MRA) and helical CT angiography (CTA) of the pulmonary arteries in the preoperative workup of patients with chronic thromboembolic pulmonary hypertension (CTEPH). The ce MRA and CTA studies of 32 patients were included in this retrospective evaluation. Image quality was scored by two independent blinded observers. Data sets were assessed for number of patent segmental, subsegmental arteries, and number of vascular segments with thrombotic wall thickening, intraluminal webs, and abnormal proximal to distal tapering. Image quality for MRA/CTA was scored excellent in 16 of 16, good in 11 of 14, m…

Abdominal and Thoracic Magnetic Resonance Angiography: Challenges, Technical Approaches, and First Clinical Applications

The main goal of magnetic resonance angiography (MRA) is to enrich the huge potential of magnetic resonance imaging (MRI) by additional morphological and functional information about the vasculature. In spin echo sequences fast flowing blood leads to signal extinction, providing high contrast between tissue and vascular structures without the need for contrast media. However, various artifacts are frequently observed which alter the assessment of the vasculature. They are due to alterations of flow (slow velocity or turbulences) or induced by the acquisition technique (Mills et al. 1983; Bradley and Waluch 1985). By using gradient echo sequences, high-quality angiograms can be obtained from…

Computertomographie der Nieren nach Tumorenukleation

Two weeks to 120 months after enucleation of renal tumours the postoperative defects were correctly localized by renal computed tomography in 34 patients. Typical defect morphology was either wedge-shaped or concave. No dependence on tumour localization, tumour size, operative technique or a certain surgeon was observed. The cortical defects were smaller (mean 2.0 cm) than the original, prominent tumours (mean 3.4 cm). In small defects without tension suture of the capsule is sufficient, leading to minor defects. Larger defects were closed with a retroperitoneal or free peritoneal fat flap resulting in larger residual defects. In case of intra- or postoperative bleeding, CT could demonstrat…

Effect of chest compressions only during experimental basic life support on alveolar collapse and recruitment

Summary Aim The importance of ventilatory support during cardiac arrest and basic life support is controversial. This experimental study used dynamic computed tomography (CT) to assess the effects of chest compressions only during cardiopulmonary resuscitation (CCO-CPR) on alveolar recruitment and haemodynamic parameters in porcine model of ventricular fibrillation. Materials and methods Twelve anaesthetized pigs (26±1kg) were randomly assigned to one of the following groups: (1) intermittent positive pressure ventilation (IPPV) both during basic life support and advanced cardiac life support, or (2) CCO during basic life support and IPPV during advanced cardiac life support. Measurements w…

Relationship between clinical and radiological signs of bronchiectasis in COPD patients: Results from COSYCONET.

Bronchiectasis (BE) might be frequently present in COPD but masked by COPD symptoms. We studied the relationship of clinical signs of bronchiectasis to the presence and extent of its radiological signs in patients of different COPD severity. Visit 4 data (GOLD grades 1-4) of the COSYCONET cohort was used. Chest CT scans were evaluated for bronchiectasis in 6 lobes using a 3-point scale (0: absence, 1: ≤50%, 2: >50% BE-involvement for each lobe). 1176 patients were included (61%male, age 67.3y), among them 38 (3.2%) with reported physicians' diagnosis of bronchiectasis and 76 (6.5%) with alpha1-antitrypsin deficiency (AA1D). CT scans were obtained in 429 patients. Within this group, any sign…

Pulmonary emphysema in cystic fibrosis detected by densitometry on chest multidetector computed tomography.

BackgroundHistopathological studies on lung specimens from patients with cystic fibrosis (CF) and recent results from a mouse model indicate that emphysema may contribute to CF lung disease. However, little is known about the relevance of emphysema in patients with CF. In the present study, we used computationally generated density masks based on multidetector computed tomography (MDCT) of the chest for non-invasive characterization and quantification of emphysema in CF.MethodsVolumetric MDCT scans were acquired in parallel to pulmonary function testing in 41 patients with CF (median age 20.1 years; range 7-66 years) and 21 non-CF controls (median age 30.4 years; range 4-68 years), and subj…

Spiral CT of bronchial arteries in chronic thromboembolism.

OBJECTIVE: Computed tomography study of bronchial artery anatomy and evaluation of dilatation and tortuousity as indicators for pulmonary hypertension and surgical risk in patients with chronic thromboembolism were performed. MATERIALS AND METHODS: We retrospectively reviewed contrast-enhanced, thin section spiral CT scans of 39 patients undergoing pulmonary thromboendarterectomy. Findings were compared with mean pulmonary artery (PA) pressure in all, postoperative mortality in 33, and postoperative CT in 5 patients. Twenty patients without pulmonary hypertension served as controls. RESULTS: In the pulmonary hypertension group, 50 bronchial arteries were observed in 30 of 39 patients. Their…

Quantification of Lung Volume at Different Tidal Volumes and Positive End-Expiratory Pressures in a Porcine Model by Using Retrospective Respiratory Gated 4D-Computed Tomography

PURPOSE: This feasibility study in healthy animals should prove the concept that it is possible to quantitatively assess the effects of different ventilatory settings on the lung parenchyma during ongoing ventilation in respiratory gated 4-dimensional (D)-computed tomography (CT). For this purpose, the influence of different tidal volumes and positive end-expiratory pressure (PEEP) on quantitative assessment of lung volumes (LVs) and lung compartments was analyzed. METHODS: Five anesthetized and ventilated (20 breaths/min, inspiratory/expiratory ratio of 1:2) healthy pigs underwent 16-row multidetector CT with retrospective respiratory gating using a noncontact charge-coupled device camera …

Neue Entwicklungen in der MRT des Thorax

Wegen technischer und physikalischer Einschrankungen wurde die MRT bisher nur selten zur Darstellung der Lunge eingesetzt. Neue Entwicklungen haben allerdings die Moglichkeiten der anatomischen Darstellung mittels MRT erheblich verbessert und gleichzeitig neue Perspektiven fur funktionelle Darstellungen eroffnet. Dazu gehoren Techniken zur funktionellen Untersuchung der Perfusion (Kontrastmittel, MR-Angiographie) und der Ventilation der Lunge (inhalierte aerosolierte Kontrastmittel, Sauerstoff, hochpolarisierte Edelgase [He-3, Xe-129] und fluorinierte Gase [SF6]). Die Gleichmasigkeit der Ventilation, Bestimmung von Lungenvolumina, Grose der Luftraume, intrapulmonale Sauerstoffkonzentration,…

Contrast-enhanced MRI of the lung

The lung has long been neglected by MR imaging. This is due to unique intrinsic difficulties: (1) signal loss due to cardiac pulsation and respiration; (2) susceptibility artifacts caused by multiple air-tissue interfaces; (3) low proton density. There are many MR strategies to overcome these problems. They consist of breath-hold imaging, respiratory and cardiac gating procedures, use of short repetition and echo times, increase of the relaxivity of existing spins by administration of intravenous contrast agents, and enrichment of spin density by hyperpolarized noble gases or oxygen. Improvements in scanner performance and frequent use of contrast media have increased the interest in MR ima…

Quantitative analysis of emphysema in 3D using MDCT: Influence of different reconstruction algorithms

Abstract Purpose The aim of the study was to compare the influence of different reconstruction algorithms on quantitative emphysema analysis in patients with severe emphysema. Material and methods Twenty-five patients suffering from severe emphysema were included in the study. All patients underwent inspiratory MDCT (Aquilion-16, slice thickness 1/0.8 mm). The raw data were reconstructed using six different algorithms: bone kernel with beam hardening correction (BHC), soft tissue kernel with BHC; standard soft tissue kernel, smooth soft tissue kernel (internal reference standard), standard lung kernel, and high-convolution kernel. The only difference between image data sets was the algorith…

Segmentation and virtual exploration of tracheobronchial trees

Abstract The tracheobronchial tree as part of the lung is part of one of the most important organs of the human body. Inhaled air is distributed to the alveolus where oxygen and carbon dioxide exchange between air and blood takes place. In this paper, we introduce the virtual endoscopy system VIVENDI to perform virtual inspections of tracheobronchial trees based on their segmentation and of the complementing blood vessels. It is based on a hybrid segmentation pipeline which enables the segmentation of vascular and tracheobronchial structures down to the seventh generation of the bronchi.

Bone marrow after autologous blood stem cell transplantation and total body irradiation: magnetic resonance and chemical shift imaging.

Magnetic resonance studies of the lumbar, pelvic, and femoral bone marrow were performed in 10 patients after autologous blood stem cell transplantation, including total body irradiation and myeloablative chemotherapy. The posttreatment interval varied between 2 and 6 yr. The appearance on T1-weighted images and the quantitative data obtained from chemical shift imaging (relative fat signal) were compared to 10 age-matched healthy volunteers. The classification of the T1-weighted images yielded no significant differences between the two groups. Chemical shift imaging by determination of the relative fat signal was able to detect a significant fatty replacement of the patients' lumbar (p < .…

MRI in lung transplant recipients using hyperpolarized 3He: comparison with CT.

PURPOSE To elucidate the ability of 3He-MRI to detect ventilation defects in lung transplant recipients, 3He-MRI was compared to CT for concordance. MATERIALS AND METHODS We examined 14 lung recipients using 3He-MRI on a 1.5 T MR scanner. CT served as a reference method. Up to four representative ventilation defects were defined for each lung on 3He-MRI and compared to corresponding areas on CT. RESULTS Altogether, 59 representative ventilation defects were defined on 3He-MRI. Plausible CT correlates were found for 29 ventilation defects; less plausible CT correlates were found for eight defects. In 22 defects (37%) no corresponding CT changes were detected. CT demonstrated correlates for v…

Measurements of alveolar pO2 using 19F-MRI in partial liquid ventilation.

Rationale and Objectives: Partial liquid ventilation using Perfluorcarbon (PFC) is an innovative treatment of acute respiratory distress syndrome. However, the underlying mechanisms are not totally clear. The aim was to investigate the distribution of oxygen partial pressure within the PFC-filled lung (ppO 2 ). Methods: Nine pigs underwent partial liquid ventilation, receiving 20 mL PFC/kg bodyweight (bw). Measurements were obtained by a chemical shift selective TurboFLASH sequence at different axial lung levels. ppO 2 was calculated from 1 9 F-MRI by nonlinear curve T 1 -fitting technique after noise correction. Results: Quantification and distribution of ppO 2 was performed successfully. …

About Objective 3-D Analysis of Airway Geometry in Computerized Tomography

The technology of multislice X-ray computed tomography (MSCT) provides volume data sets with approximately isotropic resolution, which permits a noninvasive 3-D measurement and quantification of airway geometry. In different diseases, like emphysema, chronic obstructive pulmonary disease (COPD), or cystic fribrosis, changes in lung parenchyma are associated with an increase in airway wall thickness. In this paper, we describe an objective measuring method of the airway geometry in the 3-D space. The limited spatial resolution of clinical CT scanners in comparison to thin structures like airway walls causes difficulties in the measurement of the density and the thickness of these structures.…

Fatal venous air embolism: proof and volumetry by helical CT

Hyperpolarized 3helium gas as a novel contrast agent for functional MRI of ventilation.

The use of inhaled hyperpolarized 3He gas in MRI is a recent approach for ventilation imaging. It has recently received enormous interest since it is capable of producing new and regional information on normal and abnormal lung ventilation. Promising preclinical and preliminary clinical results are the driving force to start phase II trials with patients suffering from obstructive and restrictive lung diseases.

Bolus-enhanced renal spiral CT: technique, diagnostic value and drawbacks

Abstract In addition to pre- and postcontrast renal CT scans, early bolus-enhanced spiral scans during demarcation of the corticomedullary junction were acquired in 85 patients. The diagnostic value and drawbacks of the three imaging series in the evaluation of renal disease were assessed. Renal calcifications and calculus disease detected at precontrast scans (18%) were obscured after contrast administration and excretion in most cases. In the detection of renal lesions bolus-enhanced spiral CT and delayed postcontrast scans had an identical diagnostic yield (94%). Bolus-enhanced spiral CT was superior in the assessment of lesion vascularity and vascular anatomy as well as opacification of…

Mesopolysaccharides: The extracellular surface layer of visceral organs

The mesothelium is a dynamic and specialized tissue layer that covers the somatic cavities (pleural, peritoneal, and pericardial) as well as the surface of the visceral organs such as the lung, heart, liver, bowel and tunica vaginalis testis. The potential therapeutic manipulation of visceral organs has been complicated by the carbohydrate surface layer—here, called the mesopolysaccharide (MPS)—that coats the outer layer of the mesothelium. The traditional understanding of MPS structure has relied upon fixation techniques known to degrade carbohydrates. The recent development of carbohydrate-preserving fixation for high resolution imaging techniques has provided an opportunity to re-examine…

Structural and Functional Characterization of Chronic Obstructive Lung Disease and Emphysema Using 3He- MRI: Comparison with CT and Pulmonary Function Tests

mor types. For these reasons, Matrigel impregnated with angiogenic hormone, basic-Fibroblast Growth Factor (bFGF), in a mouse model has been extensively used in fundamental angiogenesis research to induce endothelial cell differentiation and successfully allow the study of different phases of the angiogenesis process. The objective of this study was to evaluate the ability of functional ultrasound imaging (fUSI) to provide data allowing the quantification of the angiogenic process, using the Matrigel model.

Dynamic computed tomography: a novel technique to study lung aeration and atelectasis formation during experimental CPR

Objective: To develop an image based technique to study the effect of different ventilatory strategies on lung ventilation and alveolar recruitment during cardiopulmonary resuscitation (CPR). Design: (1) Technical development of the following components: (a) construction of an external chest compression device, which does not interfere with CT imaging, and (b) development of a software tool to detect lung parenchyma automatically and to calculate radiological density parameters. (2) Feasibility studies: three strategies of CPR ventilation were performed and imaged in one animal each (pigs, 25 kg): volume-constant ventilation (VCV), no ventilation, or continuous airway pressure (CPAP). One m…

Normal and abnormal pulmonary ventilation: visualization at hyperpolarized He-3 MR imaging.

To assess the feasibility of helium-3 magnetic resonance (MR) imaging with a three-dimensional fast low-angle shot (FLASH) sequence, He-3 gas (volume, 300 mL; pressure, 3 x 10(5) Pa; polarized up to 45% by means of optimal pumping) was inhaled by five healthy volunteers and five patients with pulmonary diseases. All breath-hold examinations (22-42 seconds) were completed successfully. Normal ventilation was depicted with homogeneous high signal intensity, lesions were depicted as causing defects, and obstructive lung disease was depicted with severely inhomogeneous signal intensity.

Clinical aspects of the apparent diffusion coefficient in 3He MRI: results in healthy volunteers and patients after lung transplantation.

Purpose To measure the apparent diffusion coefficient (ADC) after inhalation of hyperpolarized 3He in healthy volunteers and lung transplant recipients, and demonstrate the gravity dependence of ADC values. Materials and Methods Six healthy volunteers, 10 patients after single-lung transplantation, and six patients after double-lung transplantation were examined at 1.5T during inspiration and expiration. The inhalation of 300 mL of hyperpolarized 3He was performed with a computer-controlled delivery device. A two-dimensional fast low-angle shot (FLASH) sequence measured the 3He diffusive gas movement. From these data the ADC was calculated. Results The mean ADC was 0.143 cm2/second in healt…

Value of routine abdominal and lymph node sonography in the follow-up of breast cancer patients.

Abstract Objective: The aim of this study was to review usefulness and intervals for abdominal sonography during the follow-up of breast cancer patients. Additionally, we assessed the value of regional lymph node sonography in patients with possible locoregional recurrence. Subjects: Retrospectively, 2657 abdominal ultrasound examinations of 414 patients and 299 sonographic examinations of the regional lymph nodes in 227 patients after surgical treatment for breast cancer were evaluated. Results: Follow-up abdominal sonography revealed metastases in 6.8% of patients, and in 1% of examinations. There was no dependence on the initial T- or N-stage. At sonography of the regional lymph nodes in…

Assessment of lung microstructure with magnetic resonance imaging of hyperpolarized Helium-3

Magnetic resonance imaging of the apparent diffusion coefficient (ADC) of hyperpolarized Helium-3 is a new technique for probing pulmonary microstructure in vivo. The aim of this study was the assessment of potential sources of systematic errors of the ADC measurement. The influence of macroscopic motion was determined by measurements at two different delays after initiating the breath-hold, and before and after cardiac arrest. An intercentre comparison was performed in two age- and lung function-matched groups of lung-healthy volunteers at two research sites. Moreover, measurements of diffusion anisotropy were performed. We found no dependency of the ADC as a function of the delay after st…

The Adverse Events and Hemodynamic Effects of Adenosine-Based Cardiac MRI

OBJECTIVE We wanted to prospectively assess the adverse events and hemodynamic effects associated with an intravenous adenosine infusion in patients with suspected or known coronary artery disease and who were undergoing cardiac MRI. MATERIALS AND METHODS One hundred and sixty-eight patients (64 ± 9 years) received adenosine (140 µg/kg/min) during cardiac MRI. Before and during the administration, the heart rate, systemic blood pressure, and oxygen saturation were monitored using a MRI-compatible system. We documented any signs and symptoms of potential adverse events. RESULTS In total, 47 out of 168 patients (28%) experienced adverse effects, which were mostly mild or moderate. In 13 patie…

Diagnostik der akuten Lungenembolie mittels Spiral-CT und 3D-Rekonstruktion

Ziel: Die Entwicklung von Modellen zur Evaluierung der Spiral-CT und 3D-Rekonstruktion im Nachweis der akuten Lungenembolie (LE) im Ex-vivo-Experiment. Material und Methoden: Standardisierte kunstliche Emboli definierter Grose und Geometrie wurden in Schweinelungen eingebracht. Ausgusse der embolisierten Gefasbaume mit rontgenkontrastgebendem Kunstharz simulierten das CT-morphologische Vollbild einer Lungenembolie. Die Bilddaten wurden dreidimensional rekonstruiert und die Exaktheit der detektierten Emboluslokalisation durch Korrelation mit dem Originalpraparat verifiziert. Messungen an technischen Probekorpern mit eingeschlossenen Emboli definierter Grose sollten die Messgenauigkeit der ko…

Möglichkeiten und Grenzen der Spiral-CT bei der Untersuchung von Nierenbeckenkarzinomen

PURPOSE To assess the value of spiral CT in comparison to conventional CT in the staging of renal pelvic carcinoma. PATIENTS AND METHODS 35 patients with renal pelvic carcinoma underwent preoperative CT; conventional technique (n = 21) and spiral CT (n = 14) with the reconstruction of thin sections were compared. RESULTS Non-invasive or minimal invasive tumours (TA, T1, T2) could not be differentiated with either technique. Small, flat tumours (TA) or multicentric tumours may be missed, even if spiral scanning is applied. The separation of local tumour growth from infiltration is significantly improved by spiral CT (12 of 12 patients instead of 18 out of 21 patients with the conventional te…

Nachsorge des Mammakarzinoms

7865 follow-up examinations were performed on 420 patients who had had surgery for carcinoma of the breast; there were 2755 radiographs of the chest, 2660 sonographic examinations of the upper abdomen and 2450 contralateral mammograms. The most common findings were metastases seen on the chest radiographs during the 13-24 and 25-60 months intervals in 4.7% of cases. The incidence increased with initially higher tumour stages and in ductal carcinomas. Sonography of the upper abdomen showed 4.3% of liver involvement, mostly between the second and fifth year; this was independent of tumour stage or the histology of the primary tumour. Positive mammography of the contralateral breast was found …

Paired Inspiratory/Expiratory Volumetric Thin-Slice CT Scan for Emphysema Analysis

Purpose: The aim of the study was to use three-dimensional high-resolution CT scan data sets in inspiration and expiration for the quantitative evaluation of emphysema. Using an advanced dedicated semiautomatic analysis tool, the functional inspiratory/expiratory shifts of emphysema volume and clusters were quantified. The pulmonary function test (PFT) served as the clinical “gold standard.” Materials and methods: Thirty-one patients (9 women and 22 men; mean [± SD] age, 60 ± 8 years) who had severe emphysema due to COPD (Global Initiative for Chronic Obstructive Lung Disease [GOLD] class III and IV) were included in the study. All patients underwent paired inspiratory/expiratory multidetec…

3He MRI in healthy volunteers: preliminary correlation with smoking history and lung volumes

MRI with hyperpolarized helium-3 (3He) provides high-resolution imaging of ventilated airspaces. The first aim of this 3He-study was to compare observations of localized signal defects in healthy smokers and non-smokers. A second aim was to describe relationships between parameters of lung function, volume of inspired 3He and signal-to-noise ratio. With Ethics Committee approval and informed consent, 12 healthy volunteers (seven smokers and five non-smokers) were studied. Imaging was performed in a 1.5 T scanner using a two-dimensional FLASH sequence at 30V transmitter amplitude (TR/TE/α = 11 ms/4.2 ms/<10°). Known amounts of 3He were inhaled from a microprocessor-controlled delivery device…

Hybrid segmentation and virtual bronchoscopy based on CT images1

Rationale and objectives Introduction of combination of the segmentation tool SegoMeTex and the virtual endoscopy system VIVENDI to perform virtual endoscopic inspections of the human lung. This virtual bronchoscopy system enables visualization of the tracheobronchial tree down to seventh generation. Furthermore, the modified virtual system visualizes hidden structures such as segmented vascular system or tumors. Materials and methods The segmentation is based on image data acquired by a multislice computed tomography scanner. SegoMeTex is used to segment the tracheobronchial tree by a hybrid system with minimal user action. Similarly, the complementary pulmonary arterial can be segmented, …

Functional MRI of the lung using hyperpolarized 3-helium gas

Lung imaging has traditionally relied on x-ray methods, since proton MRI is limited to some extent by low proton density in the lung parenchyma and static field inhomogeneities in the chest. The relatively recent introduction of MRI of hyperpolarized noble gases has led to a rapidly evolving field of pulmonary MRI, revealing functional information of the lungs, which were hitherto unattainable. This review article briefly describes the physical background of the technology, and subsequently focuses on its clinical applications. Four different techniques that have been used in various human investigations are discussed: ventilation distribution, ventilation dynamics, and small airway evaluat…

3D-Segmentierung des menschlichen Tracheobronchialbaums aus CT-Bilddaten

Zur Erstellung eines mathematischen Lungenmodells zur Simulation individueller inhalativer Therapien ist die genaue Geometrie des menschlichen Tracheobronchialbaums notwendig. Diese wird durch eine intelligente 3D-Segmentierung aus CT-Datensatzen gewonnen. Der hybride Algorithmus wurde umfangreich auf unterschiedlichen Bildmaterialien manuell evaluiert.

Computed tomography-based tracheobronchial image reconstruction allows selection of the individually appropriate double-lumen tube size

Objectives: To determine whether individualized selection of double-lumen tubes or alternatives based on three-dimensional reconstruction of the tracheobronchial image from routine preoperative computed tomography (CT) scans leads to clinically appropriate choices. Design: Prospective observational study; comparison to historic controls. Setting: Anesthesia and radiology facilities of a university medical center. Participants: Forty-nine patients undergoing thoracic surgery requiring one-lung ventilation. Interventions: Three-dimensional image reconstruction of individual tracheobronchial anatomy was performed from routine preoperative spiral CT scans as well as from scans of five left-side…

Pulmonary artery sarcoma mimicking chronic thromboembolic disease: computed tomography and magnetic resonance imaging findings.

The diagnosis of the rare primary malignant tumors of the pulmonary arteries is often delayed as symptoms are nonspecific.Computed tomography (CT) and magnetic resonance imaging (MRI) of three patients with occlusion of the right pulmonary artery, two with sarcoma and one with chronic thromboembolic disease were analyzed for discriminating diagnostic criteria.Criteria suggesting pulmonary artery sarcoma are inhomogeneous high or low attenuation (hemorrhage, necrosis), soft-tissue density in pulmonary arteries, vascular distension, enhancement after administration of gadopentetate dimeglumine. Criteria for chronic thromboembolic disease are homogeneous soft-tissue lesions, abrupt vascular na…

Three-dimensional helical CT of the tracheobronchial tree: evaluation of imaging protocols and assessment of suspected stenoses with bronchoscopic correlation.

To assess the accuracy of three-dimensional (3D) helical CT of normal airways, we evaluated different imaging protocols in test objects and patients. The clinical value of 3D helical CT was composed with bronchoscopy in patients with suspected stenoses, especially before and after endobronchial procedures.Solid test objects--one of central airways and one of peripheral airways--were scanned and assessed for volume defects and stairstep artifacts. Fifty helical studies were performed in 36 patients. We evaluated these images for visualization of segmental bronchi; frequency of artifacts; and presence, localization, and degree of stenoses. Bronchoscopic correlation was available for 40 CT exa…

Pneumonia in Febrile Neutropenic Patients and in Bone Marrow and Blood Stem-Cell Transplant Recipients: Use of High-Resolution Computed Tomography

PURPOSE: To obtain statistical data on the use of high-resolution computed tomography (HRCT) for early detection of pneumonia in febrile neutropenic patients with unknown focus of infection. MATERIALS AND METHODS: One hundred eighty-eight HRCT studies were performed prospectively in 112 neutropenic patients with fever of unknown origin persisting for more than 48 hours despite empiric antibiotic treatment. Fifty-four of these studies were performed in transplant recipients. All patients had normal chest roentgenograms. If pneumonia was detected by HRCT, guided bronchoalveolar lavage was recommended. Evidence of pneumonia on chest roentgenograms during follow-up and micro-organisms detected…

Dynamic19F-MRI of pulmonary ventilation using sulfur hexafluoride (SF6) gas

A new method for dynamic imaging of pulmonary wash-in and wash-out kinetics of inhaled sulfur hexafluoride (SF6) gas was developed. Measurements at the fluorine-19 Larmor frequency were performed in pigs using a gradient echo pulse sequence with 0.5 ms echo time and a measurement time of 9.1 s per image. Dynamic MRI was performed during wash-in and wash-out of SF6 gas in mechanically ventilated porcine lungs. A postprocessing strategy was developed for quantitative determination of wash-out time constants in the presence of noise. Mean wash-out constants were 4.78 ± 0.48 breaths vs. 4.33 ± 0.76 breaths for left and right lung when ventilation was performed with low tidal volume, and 1.73 ± …

"Screening for lung cancer: Does MRI have a role?' [European Journal of Radiology 86 (2017) 353-360].

MRI of the pulmonary parenchyma.

Imaging of the pulmonary parenchyma represents a unique challenge for MRI. Limited signal is caused by low proton density, susceptibility artifacts, and physiological motion (cardiac pulsation, respiration). Recently, further improvements in MRI techniques have widened the potential for investigations of pulmonary parenchymal disease. These include very short echo times, ultrafast turbo-spin-echo acquisitions, projection reconstruction technique, breathhold imaging, ECG triggering, contrast agents (perfusion imaging, aerosols), sodium imaging, hyperpolarized noble gas imaging, and oxygen enhancement. By using widely available techniques, MRI is helpful in the assessment of (a) acute alveoli…

Functional MR imaging of pulmonary ventilation using hyperpolarized noble gases.

The current status of experimental and clinical applications for functional MR imaging of pulmonary ventilation using hyperpolarized noble gases are reviewed. 3-helium (3He) and 129-xenon (129Xe) can be hyperpolarized by optical pumping techniques such as spin exchange or metastability exchange in sufficient amounts. This process leads to an artificial, non-equilibrium increase of the density of excited nuclei which represents the source of the MR signal. Those hyperpolarized gases are administered mostly via inhalation, and will fill airways and airspaces allowing for ventilation imaging. Recent human studies concentrate on imaging the airways and airspaces with high spatial resolution. N…

Fatty replacement of bone marrow after radiation therapy for Hodgkin disease: Quantification with chemical shift imaging

The authors studied the long-term fatty replacement of bone marrow in 23 patients who had received radiation therapy for Hodgkin disease, with T1-weighted magnetic resonance imaging and quantitative chemical shift imaging. T1-weighted images revealed a mostly homogeneous high-signal-intensity pattern, in contrast to the hypointense pattern of nonirradiated marrow. The degree of fatty replacement was objectively assessed with chemical shift imaging, comparing patients to age-matched healthy volunteers. The authors found an increase in relative fat signal of 37% in the thoracic spine and 34% in the lumbar spine. The relative fat signal of nonirradiated pelvic and femoral marrow was decreased …

Functional Analysis in Single-Lung Transplant Recipients

Objective To develop and evaluate a postprocessing tool to quantify ventilated split-lung volumes on the basis of 3 He-MRI and to apply it in patients after single-lung transplantation (SLTX). High-resolution CT (HRCT) was employed as a reference modality providing split air-filled lung volumes. Lung volumes derived from pulmonary function test results served as clinical parameters and were used as the “gold standard.” Material and methods Eight patients (mean age, 54 years) with emphysema and six patients (mean age, 58 years) with idiopathic pulmonary fibrosis. All patients were evaluated following SLTX. HRCT was performed during inspiration (slice thickness, 1 mm; increment, 10 mm). For c…

Quantification of pulmonary blood flow (PBF): validation of perfusion MRI and nonlinear contrast agent (CA) dose correction with H(2)15O positron emission tomography (PET).

Validation of quantification of pulmonary blood flow (PBF) with dynamic, contrast-enhanced MRI is still missing. A possible reason certainly lies in difficulties based on the nonlinear dependence of signal intensity (SI) from contrast agent (CA) concentration. Both aspects were addressed in this study. Nine healthy pigs were examined by first-pass perfusion MRI using gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA) and HO positron emission tomography (PET) imaging. Calculations of hemodynamic parameters were based on a one-compartment model (MR) and a two-compartment model (PET). Simulations showed a significant error when assuming a linear relation between MR SI and CA dose in the …

Eine Mannitollösung als orales Kontrastmittel in der pelvinen MRT

PURPOSE Improvement of pelvic MRI using peroral administration of an aqueous mannitol solution. METHODS We retrospectively evaluated magnetic resonance examinations of 72 patients with suspected or proven pelvic abnormalities: In 36 patients, no bowel marking was carried out. In further 36 patients, we performed a contrast enhancement of the bowel by oral application of 1000 ml of an aqueous mannitol solution. RESULTS 8/36 (22%) patients suffered from diarrhoea, nausea or meteorism as a result of mannitol application. In group 2, an excellent bowel marking of the small intestine could be obtained in 36/36 (100%) patients. Contrast enhancement of the bowel significantly improved delineation …

19F-MRI of perflubron for measurement of oxygen partial pressure in porcine lungs during partial liquid ventilation

A method for in vivo measurement of oxygen partial pressure (pO2) in porcine lungs during partial liquid ventilation (PLV) with perflubron (PFOB) was developed. A pulse sequence for high-resolution MRI of the distribution of PFOB in the lung after intratracheal administration was developed as well. Moreover, quantitative measurements of longitudinal relaxation time T(1) of (19)F resonances for assessment of regional pO2 are described. Due to the need to acquire data during a single expiratory breathhold, only low SNRs were achieved in vivo. Therefore, simulations were performed to investigate the influence of background noise on T(1) values calculated from data with low SNR. Based on these …

CT-Angiographie der Bronchialarterien

Current issues in hyperpolarized gases in MRI: biomedical investigations and clinical applications

Diffusion-weighted MRI of the lung with hyperpolarized helium-3: A study of reproducibility

Purpose To determine the reproducibility of several parameters of the ADC measurement by calculating the scan-to-scan intrasubject variability. Materials and Methods Measurements were performed using a gradient-echo sequence with a bipolar gradient for diffusion weighting (b = 3.89 sec/cm2). Five patients with pulmonary emphysema, and six healthy-lung volunteers were included in the study. Images were acquired after inspiration of 3He during a single inspiratory breath-hold. To assess the reproducibility, the measurement was performed twice (time between measurements = 20 minutes) without repositioning the subjects. Analysis was performed on the basis of region-of-interest (ROI) analysis an…

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 …

Assessment of a single-acquisition imaging sequence for oxygen-sensitive (3)He-MRI.

MRI of the lungs using hyperpolarized helium-3 (3He) allows the determination of intrapulmonary oxygen partial pressures (pO2). The need to separate competing processes of signal loss has hitherto required two different imaging series during two different breathing maneuvers. In this work, a new imaging strategy to measure pO2 by a single series of consecutive scans is presented. The feasibility of the method is demonstrated in three healthy human volunteers. Maps and histograms of intrapulmonary pO2 are calculated. Changes in the oxygen concentration of the inhaled gas mixture are well reproduced in the histograms. Monte Carlo (MC) simulations of the temporal evolution of 3He hyperpolariza…

MRI of the lungs using hyperpolarized noble gases

The nuclear spin polarization of the noble gas isotopes (3)He and (129)Xe can be increased using optical pumping methods by four to five orders of magnitude. This extraordinary gain in polarization translates directly into a gain in signal strength for MRI. The new technology of hyperpolarized (HP) gas MRI holds enormous potential for enhancing sensitivity and contrast in pulmonary imaging. This review outlines the physics underlying the optical pumping process, imaging strategies coping with the nonequilibrium polarization, and effects of the alveolar microstructure on relaxation and diffusion of the noble gases. It presents recent progress in HP gas MRI and applications ranging from MR mi…

Automatic detection and quantification of ground-glass opacities on high-resolution CT using multiple neural networks: comparison with a density mask.

We compared multiple neural networks with a density mask for the automatic detection and quantification of ground-glass opacities on high-resolution CT under clinical conditions.Eighty-four patients (54 men and 30 women; age range, 18-82 years; mean age, 49 years) with a total of 99 consecutive high-resolution CT scans were enrolled in the study. The neural network was designed to detect ground-glass opacities with high sensitivity and to omit air-tissue interfaces to increase specificity. The results of the neural network were compared with those of a density mask (thresholds, -750/-300 H), with a radiologist serving as the gold standard.The neural network classified 6% of the total lung a…

Assessment of the relationship between lung parenchymal destruction and impaired pulmonary perfusion on a lobar level in patients with emphysema.

Abstract Purpose To assess the relationship between lung parenchymal destruction and impaired pulmonary perfusion on a lobar level using CT and MRI in patients with emphysema. Material and methods Forty-five patients with severe emphysema (GOLD III and IV) underwent inspiratory 3D-HRCT and contrast-enhanced MR-perfusion (1.5T; 3.5 mm × 1.9 mm × 4 mm). 3D-HRCT data was analyzed using a software for detection and visualization of emphysema. Emphysema was categorized in four clusters with different volumes and presented as overlay on the CT. CT and lung perfusion were visually analyzed for three lobes on each side using a four-point-score to grade the abnormalities on CT (1: predominantly smal…

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…

Analysis of atelectasis, ventilated, and hyperinflated lung during mechanical ventilation by dynamic CT.

Study objective: To study the dynamics of lung compartments by dynamic CT (dCT) imaging during uninterrupted pressure-controlled ventilation (PCV) and different positive end-expiratory pressure (PEEP) settings in healthy and damaged lungs. Design: Experimental animal investigation. Setting: Experimental animal facility of a university department. Interventions: In seven anesthetized pigs, static inspiratory pressure volume curves were obtained to identify the individual lower inflection point (LIP) before and after saline solution lung lavage. During PCV, PEEP was adjusted 5 millibars (mbar) below the individually determined LIP (LIP - 5), at the LIP, and 5 mbar above the LIP (LIP + 5). Mea…

Mikrostruktur der Lunge: Untersuchung mittels Diffusionsmessung von hochpolarisiertem 3Helium

Imaging methods to study the lung are traditionally based on x-ray or on radioactive contrast agents. Conventional magnetic resonance imaging (MRI) has only limited applications for lung imaging because of the low tissue density of protons concentration of hydrogen atoms, which are usually the basis for the imaging. The introduction of hyperpolarized noble gases as a contrast agent in MRI has opened new possibilities for lung diagnosis. The present paper describes this new technique. Diffusion-weighted MRI for assessment of the lung microstructure is presented here as an example of the new possibilities of functional imaging. Studies to determine the sensitivity of the diffusion measurement…