Contrast-enhanced CT and MR imaging of renal vessels Ibrahim S. Tuna, 1,2 Servet Tatli 2 1 Department of Radiology, Children’s Hospital of Wisconsin, Medical College of Wisconsin, 9000 West, Wisconsin Avenue, Milwaukee, WI 53226, USA 2 Department of Radiology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA Abstract In the evaluation of renal vessels, the accepted diagnostic gold standard digital subtraction angiography is now being challenged by state of the art CT and MR imaging. Currently in many centers, cross-sectional imaging modalities are being used as a first line diagnostic tool to evaluate arterial and venous system of the kidneys and conventional angiography has been reserved only for therapeutic intervention. CT and MR imaging display not only the lumen of the vessel as in conventional angiography, but also allow the visualization of the vessel wall, renal parenchyma, collecting system, and other adjacent soft tissue structures. Therefore, CT and MRI have each become a one-stop shop for a thorough evaluation of kidneys. In this pictorial essay, we reviewed normal anatomical variants and wide range of patholo- gies involving renal arteries and veins with illustrated contrast-enhanced CT and MR imaging samples. Key words: CT—MR—Renal artery—Renal vein In the evaluation of renal vessels, the accepted diagnostic gold standard, digital subtraction angiography is now being challenged by state of the art CT and MR imaging. These cross sectional imaging techniques have eliminated the catheter-induced complications from invasive angi- ography [1–3]. Currently, in many centers, cross-sec- tional imaging modalities are being used as a first line diagnostic tool to evaluate arterial and venous system of the kidneys and conventional angiography has been re- served only for therapeutic intervention [4]. Faster scanners have decreased acquisition times resulting in less motion artifacts. The acquired imaging data set has high spatial as well as longitudinal resolution allows optimal three-dimensional (3D) reconstruction in selected projections. In addition to being much safer and faster, imaging of all phases of contrast enhancement has become possible with current CT and MRI scanners during the administration of a single contrast agent bo- lus, allowing evaluation of arteries as well as veins of the kidneys. CT and MR imaging display not only the lumen of the vessel, as in conventional angiography, but also allow the visualization of the vessel wall, renal paren- chyma, collecting system, and other adjacent soft tissue structures. Therefore, CT and MRI have each become a one-stop shop for a thorough evaluation of kidneys [5]. In this pictorial essay, we reviewed normal anatomi- cal variants and wide range of pathologies involving re- nal arteries and veins with illustrated CTA and MRA samples. CTA technique Previous limitations of CT for evaluating the vascular system with older generation scanners have now been eliminated and the state-of-the-art multidetector CT systems can simultaneously acquire up to 0.5 mm colli- mations thick 320 multidetector sections in 16 cm detector width, with gantry rotation time as low as 280– 350 ms. Motion artifacts from breathing are less of a problem since high resolution imaging of the entire kid- ney and renal vessels can be obtained in a single breath hold; however, cannot be completely eliminated as each patient and their medical status including their respira- tory function is different. Thinner section thickness al- lows isotropic voxels, which is essential in order to obtain high-resolution 3D reconstruction and other post-pro- cessing displays, such as maximum projection reformat- ting. Despite utilizing ionizing radiation and nephrotoxic contrast agents, CT technique has gained a widespread use in the evaluation of renal vessels due to its avail- ability, speed, cost-effectiveness as well as diagnostic accuracy [1, 6]. Correspondence to: Ibrahim S. Tuna; email: dristuna@yahoo.com ª Springer Science+Business Media New York 2014 Abdominal Imaging Abdom Imaging (2014) DOI: 10.1007/s00261-014-0105-1