Please note that this variant describes initial imaging evaluation after the discovery, by imaging or otherwise, of symptomatic hydronephrosis with unknown cause. The choice of initial imaging in this situation is dependent on clinical context and on the information available from the means of hydronephrosis discovery (eg, CT, MR, US). Pathan et al [22] reviewed 651 patients with point-of-care US (POCUS) and CT in the setting of renal colic, finding that moderate to severe hydronephrosis on POCUS examination in patients with moderate or high risk of ureteric calculi, provided a more definitive answer regarding the presence of a stone without the need for high-dose CT scanning. In such patients, they advised a low-dose CT scan if the size and location of the stone is desired to plan surgical management. Pathan et al [22] reviewed 651 patients with POCUS and CT in the setting of renal colic, finding that moderate to severe hydronephrosis on POCUS examination in patients with moderate or high risk of ureteric calculi, provided a more definitive answer regarding the presence of a stone without the need for high-dose CT scanning. In such patients, they advised a low-dose CT scan if the size and location of the stone is desired to plan surgical management. CT Abdomen and Pelvis Without IV Contrast Although there is some evidence to support the use of CT abdomen and pelvis without IV contrast (separate from CTU) for initial imaging of patients with symptomatic hydronephrosis with unknown cause, it may be useful in this setting in some clinical situations. A more comprehensive evaluation can often be achieved with CT, MRU, or renal scintigraphy. In particular, this procedure is suitable for evaluating symptomatic patients when US is inconclusive [24]. CT abdomen and pelvis without IV contrast is particularly useful when obstructive urolithiasis is a primary concern.
Hydronephrosis on Prior Imaging Unknown Cause. Please note that this variant describes initial imaging evaluation after the discovery, by imaging or otherwise, of symptomatic hydronephrosis with unknown cause. The choice of initial imaging in this situation is dependent on clinical context and on the information available from the means of hydronephrosis discovery (eg, CT, MR, US). Pathan et al [22] reviewed 651 patients with point-of-care US (POCUS) and CT in the setting of renal colic, finding that moderate to severe hydronephrosis on POCUS examination in patients with moderate or high risk of ureteric calculi, provided a more definitive answer regarding the presence of a stone without the need for high-dose CT scanning. In such patients, they advised a low-dose CT scan if the size and location of the stone is desired to plan surgical management. Pathan et al [22] reviewed 651 patients with POCUS and CT in the setting of renal colic, finding that moderate to severe hydronephrosis on POCUS examination in patients with moderate or high risk of ureteric calculi, provided a more definitive answer regarding the presence of a stone without the need for high-dose CT scanning. In such patients, they advised a low-dose CT scan if the size and location of the stone is desired to plan surgical management. CT Abdomen and Pelvis Without IV Contrast Although there is some evidence to support the use of CT abdomen and pelvis without IV contrast (separate from CTU) for initial imaging of patients with symptomatic hydronephrosis with unknown cause, it may be useful in this setting in some clinical situations. A more comprehensive evaluation can often be achieved with CT, MRU, or renal scintigraphy. In particular, this procedure is suitable for evaluating symptomatic patients when US is inconclusive [24]. CT abdomen and pelvis without IV contrast is particularly useful when obstructive urolithiasis is a primary concern.