Renal CT with a minimal amount of iodinated contrast agent: feasibility in repetitive CT scanning mode

Introduction
Renal imaging is an important diagnostic procedure with numerous clinical applications, ranging from the characterization of renal pathology to the presurgical examination of kidney donors and the postoperative evaluation of interventions such as kidney transplantation [1]. Noninvasive angiographic protocols based on both CT and magnetic resonance technology are now well established, with generally high sensitivity and specificity [2]. Substantial advances in scanner hardware and software, particularly for CT, continue to improve the diagnostic power and safety of the examinations.
Safety is especially important in renal CT, as the use of iodinated contrast medium may cause contrast-induced nephropathy in patients whose renal function is already compromised. There is some evidence that the risk of contrast-induced nephropathy during CT depends on the volume of contrast medium, leading clinical guidelines to recommend use of the lowest possible volume [3, 4]. Therefore, there is interest in optimizing protocols for renal CT angiography that use a minimal volume of contrast medium without compromising the ability to visualize the vasculature. An innovative repetitive CT scanning mode may help achieve these goals.