Twenty-nine patients who were referred with the possible diagnosis of constrictive pericarditis underwent electrocardiographically gated transverse spin-echo magnetic resonance (MR) imaging to determine the accuracy of spin-echo MR imaging for the diagnosis of constrictive pericarditis and to compare the morphologic features of constrictive pericarditis with those of restrictive cardiomyopathy as seen on spin-echo MR images. Constrictive pericarditis was verified by means of surgery and/or catheterization in 17 patients. The sensitivity, specificity, and accuracy of MR imaging in the diagnosis of constrictive pericarditis were 88%, 100%, and 93%, respectively. Thickened pericardium was observed in 88% of patients with proved constrictive pericarditis. Pericardial thickening was not identified in patients with restrictive myocarditis (n = 4). The most frequent site of pericardial thickening was over the right ventricle. In constrictive pericarditis, the signal intensity of the thickened pericardium was similar or decreased compared with that of the myocardium. Indirect findings of impaired right ventricular diastolic filling (eg, dilatation of the inferior vena cava and right atrium) were identified in constrictive pericarditis and restrictive cardiomyopathy. MR imaging can serve as a noninvasive examination for the definitive diagnosis of constrictive pericarditis and can help distinguish between constrictive pericarditis and restrictive cardiomyopathy on the basis of pericardial thickness.

With conventional MRI, a tendency of ADCs could be predicted. ADCs may not provide additional information, especially to discriminate benign from malignant lesions.

Velocity-encoded cine magnetic resonance (MR) imaging provides two-dimensional velocity maps of a cross-sectional area of a vessel. Pulmonary flow and flow patterns in the main pulmonary artery were analyzed with velocity-encoded cine MR imaging and Doppler echocardiography in 10 patients with pulmonary hypertension (PH), one patient with a dilated main pulmonary artery, and 10 healthy subjects, and these findings were compared. Peak systolic velocity measured with velocity-encoded cine MR imaging was similar to that measured with Doppler echocardiography in healthy subjects and in patients with PH. Velocity-encoded cine MR imaging demonstrated substantial differences in velocity across the vascular lumen in PH. The flow pattern in healthy subjects was different than that in patients with PH; the latter had lower peak systolic velocity and greater retrograde flow after middle to late systole. The retrograde flow observed in patients with PH reflected hemodynamic events, since it was inversely proportional to pulmonary flow volume and directly proportional to pulmonary resistance and cross-sectional area of the vessel. Velocity-encoded cine MR imaging demonstrates an inhomogeneous flow profile in PH and may serve as a noninvasive method to estimate pulmonary vascular resistance.

Seventy-seven patients underwent T1-weighted spin-echo magnetic resonance (MR) imaging. Group 1 (n = 56) consisted of patients with various types of congenital heart disease but normal pulmonary veins. Group 2 (n = 22) consisted of patients with the following conditions: partial anomalous pulmonary venous connection (n = 11), total anomalous pulmonary venous connection (n = 5), cor triatriatum (n = 4), or pulmonary vein stenosis (n = 2). In group 1, the sites of connections of all four pulmonary veins were identified with MR imaging in 88% of cases; the connections of at least three pulmonary veins were seen in all patients. In group 2, the prospective detection rate of pulmonary venous abnormalities with MR imaging was 95%. The prospective detection rates of pulmonary venous abnormalities with cardiac angiography (n = 13) and echo-cardiography (n = 13) were 69% and 38%, respectively. This study indicates that MR imaging can accurately demonstrate the normal pulmonary veins and abnormalities of the pulmonary veins.

The purpose of this study was to characterize the contrast caused by a susceptibility MRI contrast agents, on spin echo T2-weighted imaging of reperfused myocardial infarction. Our interest in this model focused on the expected requirement that such agents be compartmentalized in the tissue to cause signal loss on spin echo images, a condition which may not be present in reperfused infarcted myocardium. Accordingly, nine rats were subjected to 2 h of left coronary artery occlusion followed by 3 +/- 0.5 h of reperfusion prior to administration of contrast media. Three sets of MR images were acquired: (a) baseline axial images at the midventricle, both T1-weighted (TR/TE = 300/20) and T2-weighted (TR/TE = 1500/60); (b) T1-weighted images after administering a T1-enhancing agent, Gd-DTPA-BMA (0.2 mmol/kg), to document that contrast media is delivered to the reperfused infarction; and (c) T2-weighted images after administering the susceptibility agent, Dy-DTPA-BMA (1.0 mmol/kg). Gadolinium-enhanced T1 images depicted reperfused infarction as regions with greatly enhanced signal intensity compared with uninfarcted myocardium, indicating that contrast agent was delivered to the infarcted zone. Dysprosium-enhanced T2 images depicted the injury as a region of persistent signal intensity relative to depletion of signal in normal myocardium, consistent with failure of the contrast agent to cause signal loss. Similar infarction sizes were observed for unenhanced T2-weighted images (33 +/- 5%), gadolinium-enhanced T1-weighted images (36 +/- 5%) and postmortem staining (30 +/- 6%); strong correlations (r > 0.9) were noted in comparisons of these data.(ABSTRACT TRUNCATED AT 250 WORDS)

Quantification of pulmonary flow is clinically important in the evaluation of both congenital and acquired heart disease. Velocity-encoded cine magnetic resonance (MR) is a promising technique for measuring velocity and volume of blood flow. The authors report validation of the accuracy of velocity-encoded cine MR for measurement of oblique-angle flow in vitro, with use of a constant-flow phantom, and in vivo, with nine healthy volunteers in whom velocities were measured separately in the main, right, and left pulmonary arteries. Findings at MR were compared with findings at Doppler echocardiography. Velocity measurements in a flow phantom with cine MR correlated well with direct measurements at Doppler echocardiography. Velocity-encoded cine MR enabled accurate and reproducible measurement of absolute blood flow in healthy subjects. Oblique-gradient flow encoding (ie, flow-encoding direction coinciding with the true direction of flow) was the method of choice for velocity measurements in the right and left pulmonary arteries.

MRCP with resp 3D FR-FSE using ASSET can be routinely used for acquiring information from the pancreatobiliary system.

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