Figure 6a.  Intramural hematoma of the descending aorta. (a) Unenhanced CT scan shows a crescentic area of high attenuation (left arrow) with medial displacement of intimal calcifications (right arrow). (b) Enhanced CT scan shows the crescentic area as hypoattenuating relative to the aortic lumen. Arrow = intimal calcification. (c) Oblique sagittal MPR image shows the intramural hematoma (bottom arrow). Top arrow = intimal calcification.