This axial (cross sectional) CT image through the abdomen demonstrates a dissection of the abdominal aorta (curvilinear density across the large rounded blood vessel in the center of the image) which extends into the left (on your right) renal artery which is completely devascularized (infarcted). The right renal artery is the curvilinear white structure on the left side of the image extending to the right (on your left) kidney which demonstrates normal contrast enhancement (looks white compared with the infarcted left kidney).