Norbert I. Stauder

Multislice first-pass myocardial perfusion imaging: Comparison of saturation recovery (SR)-TrueFISP-two-dimensional (2D) and SR-TurboFLASH-2D pulse sequences

To compare signal‐to‐noise ratio (SNR), contrast‐to‐noise (CNR) ratio, and diagnostic accuracy of a newly developed saturation recovery (SR)‐TrueFISP‐two‐dimensional (2D) sequence with an SR‐TurboFLASH‐2D sequence.

Whole‐body MR angiography using a novel 32‐receiving‐channel MR system with surface coil technology: First clinical experience

To demonstrate the feasibility of detecting atherosclerotic vascular disease using an innovative magnetic resonance angiography (MRA) protocol in combination with a dedicated whole‐body MR scanner with new surface coil technology.

Subacute myocardial infarction: assessment by STIR T2-weighted MR imaging in comparison to regional function

PurposeIncreased T2 signal intensity (SI) can be regularly observed in myocardial infarction. However, there are controversial reports about the relationship of elevated T2 SI to myocardial viability and some authors propose that high T2 SI serves as a sign of irreversible myocardial injury. This study investigates increased T2 SI compared to myocardial function in patients with reperfused subacute myocardial infarction. Preserved function was used as criterion for viability.MethodsTen healthy volunteers and 17 patients with myocardial infarction and patent inlarct related coronary artery were examined on a 1.5 T Magnetom Vision system (Siemens). For T2-weighted MR imaging a breath-hold STIR sequence with dark-blood preparation was used. Cine FLASH 2D imaging was applied to assess myocardial function. Signal-to-noise (S/N) in STIR T2 images was measured in normal and infarcted regions and subsequently identified by two independent observers. Based on a 20 segment model of the left ventricle findings were compared to regional myocardial function.ResultsElevated STIR T2 SI was found in all 17 patients and observed in 27% (204/754) of segments. S/N of normal myocardium was 5.1 ±0.7 in volunteers and 4.9 ± 0.8 in patients(P=NS). Infarcted myocardium presented with significantly-increased S/N 12.8 ± 1.9 (P < 0.0001). Significant transmural elevation of T2 SI was noted in 32% of segments with preserved systolic function.ConclusionIncreased STIR T2 SI can be observed transmurally in post-ischemic myocardial regions with preserved function. It therefore cannot be used as an exclusive marker for the non-viable region.

Fat- and water-selective MR cine imaging of the human heart: assessment of right ventricular dysplasia.

RATIONALE AND OBJECTIVES The purpose of this study was to develop and implement MR sequences for chemical shift-selective breath-hold cine imaging of the heart. Fibroadipose conversion of myocardium in cases suspected of right ventricular dysplasia should be revealed in fat- and water-selective MR images of high quality. METHODS Frequency-selective saturation of one chemical shift component was applied in modified k-space-segmented, electrocardiography-gated sequences, allowing high-quality cine imaging of the human heart in a single breath-hold. Phantom studies and human examinations in eight normal subjects (aged 24-62 years) and in seven patients (aged 31-47 years) with suspected right ventricular dysplasia were performed. The patients showed suspicious findings, such as a dyskinetic and dilated right ventricle combined with ventricular arrhythmia, and underwent MR imaging after exclusion of other possible reasons (eg, coronary artery disease or pulmonary hypertension). RESULTS High selectivity to the desired chemical shift component was confirmed by test measurements in a phantom containing water and lipids. In the human subjects, minor problems with magnetic field inhomogeneities appeared in the thoracic walls only. Four patients with suspected right ventricular dysplasia showed clearly abnormal signal behavior of the right myocardial wall in both fat- and water-selective cine images. Bright transmural structures were exhibited in fat-selective images, but the origin of the fat (epicardium or infiltrated myocardium) was often difficult to assess. CONCLUSIONS Right ventricular areas with fibrosis and fatty degeneration often show normal signal intensity in standard T1-weighted images but can be differentiated from normal tissue by the new chemical shift-selective breath-hold cine techniques.

Semiquantitative assessment of myocardial perfusion using magnetic resonance imaging: Evaluation of appropriate thresholds and segmentation models

Rationale and Objectives:The aim of the study was to determine optimal thresholds for semiquantitative perfusion parameters and to evaluate the influence of different segmentation models in detecting malperfused regions. Material and Methods:In 6 healthy subjects and 13 patients with coronary artery disease, contrast-enhanced first-pass perfusion imaging was performed using a SR-TrueFISP-sequence. Thresholds for semiquantitative parameters were established, and different segmentation models of the left ventricular myocardium were tested. The standard of reference for patient studies was single photon emission computed tomography. Results:Optimal thresholds were determined in healthy subjects for the perfusion parameters upslope, AUC, and peak SI of mv-0.5*std, mv-1.5*std, and mv-1.0*std, respectively. Using the optimal threshold for each parameter/segmentation combination sensitivities and specificities of stress studies were between 66% and 93% and 77% and 92%, respectively. Subdivision of radial segments into subendo/subepicardial segments increased sensitivities for perfusion deficits. Conclusions:Subdivision of radial myocardial segments is essential in analysis of magnetic resonance first-pass perfusion series. Semiquantitative perfusion parameters possess different sensitivities for the detection of perfusion deficits.

Follow-Up of Cardiac Sarcoidosis by Magnetic Resonance Imaging

A 27-year-old patient presented with a chief complaint of 2 months of increasing dyspnea, vertigo, and performance decline on exertion. The physical examination and echocardiography results were unremarkable. Admission chest radiograph revealed bilateral hilar adenopathy Figure 1. An ECG showed borderline first-degree atrioventricular block. Heart rate at baseline was 68 bpm. During a stress test, atrioventricular conduction abnormalities progressed until complete heart block resulted, and the heart rate decreased to 35 bpm Figure 2. Magnetic resonance imaging (MRI) …