Unenhanced MRU relies upon heavily T2-weighted imaging of the intrinsic high signal from urine for evaluation of the urinary tract. IV contrast is administered to provide additional information regarding obstruction, urothelial thickening, focal lesions, and stones. Contrast-enhanced T1-weighted series should include corticomedullary, nephrographic, and excretory phase. Thin-slice acquisition and multiplanar imaging should be obtained. MRU is most commonly performed on a 1.5T machine, but imaging at 3T has become more widely used; however, comparison of 3T MRU and CTU has not been published in the literature. For the purposes of this document, we make a distinction between MRU and MR abdomen and pelvis without and with IV contrast. MR abdomen and pelvis without and with IV contrast is defined as any protocol not specifically tailored for evaluation of the upper and lower urinary tracts, without both the precontrast and excretory phases and without heavily T2-weighted images of the urinary tract. Renal Failure OR Discussion of Procedures by Variant Variant 1: Renal failure. Acute kidney injury (AKI), unspecified. Initial imaging. Arteriography Kidney Arteriography is reserved for intervention rather than for the initial diagnosis of AKI. Renal revascularization may be considered in a very select group of patients with AKI. There is no relevant literature regarding the use of arteriography in the evaluation of AKI. CT Abdomen and Pelvis Unenhanced CT abdomen and pelvis is useful for further evaluation of US-detected hydronephrosis by determining level and cause of obstruction. CT is the most sensitive modality for urinary tract calculi and more sensitive than US for retroperitoneal pathology [15]. Although CT can also provide an assessment of renal size and volume, it is generally not considered the first-line imaging modality for AKI [16]. CT may be considered if US is not feasible or is nondiagnostic because body habitus.
Renal Failure. Unenhanced MRU relies upon heavily T2-weighted imaging of the intrinsic high signal from urine for evaluation of the urinary tract. IV contrast is administered to provide additional information regarding obstruction, urothelial thickening, focal lesions, and stones. Contrast-enhanced T1-weighted series should include corticomedullary, nephrographic, and excretory phase. Thin-slice acquisition and multiplanar imaging should be obtained. MRU is most commonly performed on a 1.5T machine, but imaging at 3T has become more widely used; however, comparison of 3T MRU and CTU has not been published in the literature. For the purposes of this document, we make a distinction between MRU and MR abdomen and pelvis without and with IV contrast. MR abdomen and pelvis without and with IV contrast is defined as any protocol not specifically tailored for evaluation of the upper and lower urinary tracts, without both the precontrast and excretory phases and without heavily T2-weighted images of the urinary tract. Renal Failure OR Discussion of Procedures by Variant Variant 1: Renal failure. Acute kidney injury (AKI), unspecified. Initial imaging. Arteriography Kidney Arteriography is reserved for intervention rather than for the initial diagnosis of AKI. Renal revascularization may be considered in a very select group of patients with AKI. There is no relevant literature regarding the use of arteriography in the evaluation of AKI. CT Abdomen and Pelvis Unenhanced CT abdomen and pelvis is useful for further evaluation of US-detected hydronephrosis by determining level and cause of obstruction. CT is the most sensitive modality for urinary tract calculi and more sensitive than US for retroperitoneal pathology [15]. Although CT can also provide an assessment of renal size and volume, it is generally not considered the first-line imaging modality for AKI [16]. CT may be considered if US is not feasible or is nondiagnostic because body habitus.