MR-Angiographie peripherer Gefäße mit automatischer Verschiebetisch-Technik bei 1.0 T im Vergleich zur i. a. DSA

PURPOSE Contrast-enhanced (CE) 3D-MR angiography of peripheral arteries was performed in 8 patients with peripheral arterial occlusive disease by applying a new tracking technique on a 1.0 T system (Magnetom Harmony, Siemens). The studies were compared with intra-arterial digital angiography as gold standard. MATERIALS AND METHODS Imaging of the distal aorta, pelvis, upper and lower limb arteries was accomplished with a Flash-3D-sequence (TR/TE = 6.2/3.2 ms) within 26 s acquisition time of each region after a single bolus of 30 ml contrast agent. Individual circulation time was determined by a test bolus before each examination. RESULTS 112 vessel segments were evaluated. MR angiography ach…

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…

MR-Perfusionsbildgebung des Herzens mit TrueFISP

OBJECTIVE Development and test of a saturation-recovery TrueFISP (SR-Trufi) pulse sequence for myocardial perfusion MR imaging (MRI) using improved gradient hardware. MATERIAL AND METHODS Measurements were performed on a 1.5 T scanner with prototype gradients (50 mT/m, minimum rise time 300 microseconds). T1-weighted first-pass MRI of Gd-DTPA (0.025 mumol/kg) kinetics in the myocardium was performed using an SR-Trufi pulse sequence (TR/TE/alpha = 2.6 ms/1.4 ms/55 degrees) with a saturation preparation of TD = 30 ms before the TrueFISP readout. Measurements were performed in volunteers (n = 4) and in a pig model of chronic ischemia (n = 1). RESULTS In phantoms, the signal intensity was linea…

Erfahrungen mit einer 3D-Navigatorsequenz zur Koronargefäßdarstellung an einem Hochleistungs-MR-System

Purpose: To evaluate MR coronary angiography using a three-dimensional navigator echo sequence on a MR scanner with a high performance gradient system. Material and Methods: Five healthy volunteers were examined with a 1.5 Tesla MR system, using a high performance prototype gradient system (peak amplitude 50 mT/m, rising time 600 μs). For imaging, a navigated gradient-echo pulse sequence with an in-plane resolution between 0.63 × 0.63 and 0.78 × 0.78 mm 2 was used. Per patient two overlapping slabs were acquired. The number of visualised coronary artery segments was estimated (AHA classification). In addition, signal-to-noise measurements were performed in the ascending aorta at the level o…

MRT bei chronischer Epicondylitis humeri radialis an einem 1,0 T-Gerät - Kontrastmittelgabe notwendig?

T: Is Gd-DTPA administration useful Purpose: Evaluation of the diagnostic value and confidence of contrast-enhanced MR imaging in patients with lateral epicondylitis in comparison to clinical diagnosis. Material and Methods: 42 consecutive patients with clinically proven chronic lateral epicondylitis and 10 ellbow joints of healthy controls have been examined on a 1.0 T MR-unit. Criteria for inclusion in the prospective study were: persistant pain and a failed conservative therapy. The MR protocol included STIR sequence, a native, T 2 -weighted, fat-supressed TSE sequence, and a Flash-2-D sequence. Also, fatsupressed, T 1 -weighted SE sequences before and after administration of Gd-DTPA con…

Flussquantifizierung in Koronar- und Bypass- gefäßen mit der MR-Phasenkontrasttechnik

Ziel: Es sollte die Genauigkeit der MR-Phasenkontrastmethode zur Ermittlung des Flusses in Koronararterien und koronaren Bypassgefasen bestimmt werden. Material und Methode: Die MRT-Flussmessungen von 12 Patienten mit 22 Bypassgefasen wurden mit intraoperativ mittels Ultraschalldurchflussmethode bestimmten Flussen verglichen. Praoperativ wurden zusatzlich Flussmessungen in 28 Koronararterien von 20 Patienten durchgefuhrt. Zur MRT-Flussmessung wurde eine segmentierte 2D-Flash-Sequenz verwendet, die eine zeitliche Auflosung von 110 bzw. 125 ms aufwies. Dies ermoglichte die Akquisition von 6–8 Bildpaaren pro Herzzyklus. Ergebnisse: Es bestand eine signifikante Korrelation zwischen den Ergebnis…

Kontrastverstärkte MR-Angiographie abdomineller Gefäßean einem 1.0 T-System*

Purpose To evaluate the efficacy of breath-hold, three-dimensional, contrast-enhanced magnetic resonance angiography with a 1.0 T system for imaging the abdominal vessels in comparison to conventional arteriography (CA). Methods The abdominal aorta and visceral arteries were studied in 54 patients (60 examinations) on a 1.0 T scanner using an ultrafast gadolinium-enhanced gradient-echo sequence with the following parameters: TR/TE = 3.8/1.4 ms, flip angel 25 degrees, matrix 198 x 256, field 380-420 mm, pixel size 1.9 x 1.48 mm2, slice thickness 1.5-2.5 mm, acquisition time 22-26 sec. Individual circulation times were determined by a test bolus before each MR angiography. Conventional arteri…

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…

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…

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…

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…

Kontrastmittelverstärkte dreidimensionale MR-Angiographie der Lungenarterien bei Patienten mit chronisch-rezidivierender Lungenembolie - Vergleich mit der selektiven intraarteriellen DSA∗ *

Purpose: This study compares contrast-enhanced 3D-MR angiography (MRA) of the pulmonary arteries with selective intraarterial DSA in patients with chronic thromboembolic pulmonary hypertension. Materials and Methods: 20 patients preoperatively underwent a contrast-enhanced 3D-MRA of the pulmonary arteries at 1.5T using the phased-array body coil. For MRA, we used a 3D-Flash-sequence after bolus timing. 2 radiologists analyzed the acquired image material in consensus with respect to the detection of central thromboembolic material and the visualization of the pulmonary arterial tree. Finally, the MR angiograms were compared with selective DSA images using surgical findings as the definitive …

Assessment of the distal anastomosis of coronary artery bypass grafts with a 2D T2-weighted turbo spin echo sequence and correlation to conventional coronary angiography

Abstract Objective The aim of the study was to evaluate the patensies of the distal anastomoses of coronary artery bypass grafts and to detect graft stenoses and occlusions with a magnetic resonance (MR) spin echo sequence. Patients and methods One hundred and eighty-five patients with 481 distal anastomoses were examined with a 1.5 T MR scanner and coronary angiography. A 2-dimensional T2-weigthed breath-hold half-Fourier acquisition single-shot turbo spin echo sequence (Haste) was performed. All images were evaluated independently by a radiologist and cardiologist and compared to the conventional coronary angiography. The observers were blinded to the coronary angiography findings, but in…

Kernspintomographische Flussquantifizierung in Koronargefäßen zur Evaluierung hochgradiger Koronarstenosen

Ziel: Zweck der Studie war die Bestimmung des intrakoronaren Blutflusses im Verhaltnis zum Aortenfluss bei Patienten mit hochgradigen Koronarstenosen. Die MR-Flussmessung wurde bei 15 Patienten in 18 Koronargefasen durchgefuhrt. Zur Flussmessung eine segmentierte 2-D-Flash-Sequenz mit einer zeitlichen Auflosung von 110 bzw. 125 ms verwendet. Der mittlere Koronarfluss im Verhaltnis zum aortalen Fluss war bei Patienten mit hochgradigen Koronarstenosen signifikant (p < 0,001) erniedrigt. Die MR-Phasenkontrastmethode ermoglicht eine genaue Bestimmung des Blutflusses in Koronargefassen und in Korrelation zum Aortenfluss eine Aussage uber hochgradige Koronarstenosen. Weiterentwicklungen der Metho…

Kontrastverstärkte dreidimensionale MR-Angiographie der A. carotis bei 1,0 Tesla im Vergleich zuri.a. DSA - ist die Methode für die Diagnostik von Karotisstenosen geeignet?

Artery Disease? Purpose: To evaluate the efficacy of three-dimensional, contrast-enhanced magnetic resonance angiography (CE-MRA) of the carotid artery with a 1.0 system in comparison to intra-arterial conventional angiography (i.a.CA) for the assessment of carotid artery disease. Method: 55 patients with suspected stenosis of the carotid artery were examined with a 3D-CE gradient-echo sequence on a 1.0 T scanner (TR/TE = 6.2/2.2 ms) and a selective DSA i.a. angiography. Image quality was evaluated by estimating the arterial contrast and venous enhancement. Morphological pathologies were registered for all arteries, stenoses of the internal carotid artery were graded by applying the NASCET …

Prä- und postoperative Evaluation von linksventrikulären Herzspitzenaneurysmen mittels Cine-MRT

Purpose: To demonstrate the usefulness of cine-MRI for the evaluation of apical left ventricular aneurysms (ALVA) and for prediction of the surgical outcome. Materials and Methods: We investigated 28 patients with ALVA, 13 of them additionally after aneurysmectomy at 1.5 T; 15 healthy volunteers served as normal controls. For cine-MRI k-space segmented FI-2D-GE sequences were used. Analysis comprised the calculation of cardiac volume indices, cardiac function, and percentual myocardial thickening (PMT). For prediction of surgical results we divided left ventricle into an aneurysmatic and a non-aneurysmatic part. The non-aneurysmatic part was assumed as the left ventricle after surgical remo…

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)…

Dynamic contrast-enhanced myocardial perfusion imaging using saturation-prepared TrueFISP.

Purpose To develop and test a saturation-recovery TrueFISP (SR-TrueFISP) pulse sequence for first-pass myocardial perfusion imaging. Materials and Methods First-pass magnetic resonance imaging (MRI) of Gd-DTPA (2 mL) kinetics in the heart was performed using an SR-TrueFISP pulse sequence (TR/TE/α = 2.6 msec/1.4 msec/55°) with saturation preparation TD = 30 msec before the TrueFISP readout. Measurements were also performed with a conventional saturation-recovery TurboFLASH (SRTF) pulse sequence for comparison. Results SR-TrueFISP images were of excellent quality and demonstrated contrast agent wash-in more clearly than SRTF images. The signal increase in myocardium was higher in SR-TrueFISP …

Möglichkeiten und Perspektiven der nichtinvasiven Bypassdiagnostik

Ziel: Das Studienziel war die kernspintomographische Evaluierung koronarer Bypassgefase mit der Hast-, Fisp-3-D- und Navigatorsequenz unter besonderer Berucksichtigung der distalen Bypassanastomose.

Diagnose und Verlaufsbeurteilung eines intramuralen Hämatoms der Aorta ascendens mit der Magnetresonanztomographie

Paraneoplastische limbische Enzephalitis bei kleinzelligem Bronchialkarzinom

We report about a 63-year-old male patient who complained of a recent onset of confusion. A mediastinal mass had been detected in his chest X-ray three days before admission to our clinic. Surprisingly, a CT scan of the brain revealed no signs of cerebral masses or oedema. MRI demonstrated bright hyperintens signals in the medial aspect of both temporal lobes. Biopsy by mediastinoscopy showed small cell lung carcinoma (SCLC). No distant metastases were found by staging procedures. Cerebrospinal fluid and serum contained antineuronal antibodies (anti-Hu). The combination of symptoms, MRI findings and paraneoplastic antibodies established the diagnosis of paraneoplastic limbic encephalitis in…

Indirekte MR-Arthrographie zur Verlaufskontrolle nach autologer osteochondraler Transplantation

Purpose: To evaluate the spectrum of findings in indirect MR-arthrography following autologous osteochondral transplantation. Patients and Methods: 10 patients with autogenous osteochondral homografts underwent indirect MR-arthrography at three, 6 and 12 months postoperatively. The MR protocol at 1.5 T comprised unenhanced imagings with PD- and T 2 -weighted TSE-sequences with and without fat-suppression as well as T 1 -weighted fat-suppressed SE-sequences before and after iv. contrast ad ministration and after active joint exercise. Image analysis was done by two radiologists in conference and comprised the evaluation of signal intensity (Sl) and integrity of the osseous plug and the carti…

In-vitro-Untersuchung von biologischen und technischen Herzklappenprothesen im MRT: Beurteilung möglicher Anziehung und Erhitzung der Implantate

PURPOSE In vitro evaluation of possible deflection and heating of present-day prosthetic heart valves during MR imaging at 1.5 T. METHODS 17 prosthetic heart valves, 12 technical and 5 biological, were investigated using a 1.5 Tesla Siemens Vision system. Deflection was measured at the edge of a 1.5 Tesla superconducting magnet. Each valve was then submerged in a vial of a 1/1 electrolyte solution and temperature was measured before and after imaging with a turbo-spin-echo sequence (TR 5200 ms, TE 138 ms, Flip angle 180 degrees, acquisition time 10.5 minutes, length of echo train 29). MR imaging was performed with phase encoding parallel and perpendicular to the plane of the valves. RESULTS…