Two-Dimensional Breath-Hold Coronary MR Angiography in Normal Adults

PURPOSE: To assess the efficacy of two-dimensional breath-hold coronary magnetic resonance angiography (coronary MRA) in normal rolunteers. MATERIALS AND METHODS: During a four-month period, 11 volunteers underwent MRA of the major coronary branches using a 2-D multiphase breath-hold spiral fast-gradient echo sequence. The proximal diameter of each visualized coronary artery was measured, and visibility and image quality were also determined. RESULTS: Adequate visualization was achieved in 82-100% of proximal coronary arterial branches and in 36-55% of the middle, distal branches. In general, the diameter of the proximal coronary artery correlated closely with that measured from conventional coronary angiography and using previous coronary MRA data. However, visibility and image quality in the left circumflex coronary artery were limited. CONCLUSION: In the majority of subjects, 2-D coronary MRA provides adequate visualization of the proximal segments of the major coronary arterial branches.

Gadomer-17 in Contrast Enhanced MR Imaging of Reperfused Myocardial Infarction in a Cat Model

PURPOSE: To evaluate in reperfused myocardial infarction in a cat model, the time-course of signal enhancement as seen on Gadomer-17 enhanced MRI, and to correlate the size of the enhanced area with that of the infarct area as revealed by on histochemical examination. MATERIALS AND METHODS: Five cats which had undergone occlusion of the LAD followed by reperfusion underwent MR imaging. After T2-weighted imaging, Gadomer-17 enhanced T1-weighted images were obtained in four cats during a six-hour period, and in one during a three-hour period. Signal intensities were measured in the enhanced and non-enhanced areas of enhanced T1-weighted images. and using 2,3,5-triphenyl tetrazolium chloride (TTC) histochemical staining, the size of the abnormal signal area on each image was compared with that of the infarct area. RESULT: The enhanced area seen on enhanced T1-weighted images showed rapidly increased signal intensity following the administration of Gadomer-17. Maximum enhancement was detected during a 40 -60 minutes period, with an average enhancement of 168 +/-9.9% of normal myocardium. TTC staining revealed that the size of the high signal area on T2-weighted images and of the enhanced area on enhanced T1-weighted images was greater than that of the infarct area (p<0.05). CONCLUSION: In reperfused myocardial infarction in a cat model, Gadomer-17 enhanced MR imaging delineates both reversibly and irreversibly damaged myocardium, with strong enhancement and a broad temporal window. We may therefore expect that Gadomer-17 is useful for demonstrating myocardial injury.