Contrastenhanced 3d Angiography

Gadolinium-enhanced 3D MR angiography minimizes the influence of cardiac output and altered flow dynamics that might otherwise degrade techniques dependent on inflow of blood. Advantages are a rapid acquisition time without the need for ECG triggering and breath holding. The images are often more easily communicated to a surgical team. In a retrospective study, contrast-

Figure 6.1. Phase contrast sequences in MRI in a patient with severe aortic regurgitation and a type B aortic dissection. Transverse plane. A: Phase contrast in systole. The ascending aorta shows high signal intensity with fast flow toward the head (white arrow). The true lumen in the descending aorta is dark, meaning fast flow in the opposite direction (black arrow). The false lumen of the descending aorta is encoded gray similar to the surrounding structures, indicating slow flow or no flow. B: Phase contrast in diastole. The ascending aorta is now slightly dark, indicating flow towards the left ventricle, caused by aortic regurgitation. C: The corresponding magnitude image to panel A, showing the anatomic structures at the same time. D corresponds to panel B.

Figure 6.1. Phase contrast sequences in MRI in a patient with severe aortic regurgitation and a type B aortic dissection. Transverse plane. A: Phase contrast in systole. The ascending aorta shows high signal intensity with fast flow toward the head (white arrow). The true lumen in the descending aorta is dark, meaning fast flow in the opposite direction (black arrow). The false lumen of the descending aorta is encoded gray similar to the surrounding structures, indicating slow flow or no flow. B: Phase contrast in diastole. The ascending aorta is now slightly dark, indicating flow towards the left ventricle, caused by aortic regurgitation. C: The corresponding magnitude image to panel A, showing the anatomic structures at the same time. D corresponds to panel B.

enhanced MR angiography was superior to black blood imaging (spin-echo, T2 weighted, and T1 weighted) for visualizing the intimal flap in the thoracic aorta as well as supraaortic branch vessels and yielded better overall image quality10. However, intramural hematoma may be missed and the aortic wall is not depicted11. Aortic insufficiency can only be detected by cine-MRI. Therefore, 3D angiography cannot be the exclusive modality for imaging acute aortic syndromes.

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