The Tc-99m MAG3 radionuclide angiogram assesses renal perfusion, and the following scintigraphic renogram can quantity split renal function. Diuretic furosemide renography can help to confirm a dilated obstructed versus a dilated nonobstructed renal collecting system. A persistent nephrogram without excretion suggests acute tubular necrosis [25]. Measurement of effective renal plasma flow may provide prognostic information. However, Tc-99m MAG3 is not widely used in the differentiation of causes of AKI. US Kidneys Retroperitoneum US has the greatest diagnostic value in the detection of hydronephrosis associated with acute urinary tract obstruction [4]. Grayscale US is highly sensitive (>90%) for hydronephrosis and bladder distension, allowing localization of the level of obstruction and guiding intervention such as Foley catheter placement or nephrostomy/stenting [26]. However, even in hospitalized patients with AKI, the prevalence of hydronephrosis is low, ranging from 5% to 10%, with obstruction being the cause of AKI in <45.2% of patients with hydronephrosis [4,27-29]. The highest yield for US is in patients with risk factors for urinary obstruction, such as pelvic tumors, bladder disorders, prostate hypertrophy, stone disease, and pelvic surgery. In patients without risk factors for obstruction, <1% of patients had US-detected obstruction [4]. Hydronephrosis does not necessarily indicate obstruction; a distended bladder, reflux, pregnancy, postobstructive dilation, or diuresis may cause ureteral and collecting system dilatation. When the bladder is distended, the patient should be re-evaluated after the bladder has been decompressed by voiding or catheterization. False-negative US studies may be secondary to suboptimal image quality, dehydration, early obstruction, or compression of the renal pelvis or ureters by tumor or fibrosis. A secondary role of US is the evaluation of renal size, echogenicity, and morphology to differentiate AKI from CKD and allow determination of prognosis.
Renal Failure. The Tc-99m MAG3 radionuclide angiogram assesses renal perfusion, and the following scintigraphic renogram can quantity split renal function. Diuretic furosemide renography can help to confirm a dilated obstructed versus a dilated nonobstructed renal collecting system. A persistent nephrogram without excretion suggests acute tubular necrosis [25]. Measurement of effective renal plasma flow may provide prognostic information. However, Tc-99m MAG3 is not widely used in the differentiation of causes of AKI. US Kidneys Retroperitoneum US has the greatest diagnostic value in the detection of hydronephrosis associated with acute urinary tract obstruction [4]. Grayscale US is highly sensitive (>90%) for hydronephrosis and bladder distension, allowing localization of the level of obstruction and guiding intervention such as Foley catheter placement or nephrostomy/stenting [26]. However, even in hospitalized patients with AKI, the prevalence of hydronephrosis is low, ranging from 5% to 10%, with obstruction being the cause of AKI in <45.2% of patients with hydronephrosis [4,27-29]. The highest yield for US is in patients with risk factors for urinary obstruction, such as pelvic tumors, bladder disorders, prostate hypertrophy, stone disease, and pelvic surgery. In patients without risk factors for obstruction, <1% of patients had US-detected obstruction [4]. Hydronephrosis does not necessarily indicate obstruction; a distended bladder, reflux, pregnancy, postobstructive dilation, or diuresis may cause ureteral and collecting system dilatation. When the bladder is distended, the patient should be re-evaluated after the bladder has been decompressed by voiding or catheterization. False-negative US studies may be secondary to suboptimal image quality, dehydration, early obstruction, or compression of the renal pelvis or ureters by tumor or fibrosis. A secondary role of US is the evaluation of renal size, echogenicity, and morphology to differentiate AKI from CKD and allow determination of prognosis.