Some of these have shown that combining US findings with complementary KUB improved the sensitivity for urolithiasis and had acceptable specificity when compared with either modality alone [34]. In a prospective study of 206 patients with renal colic and suspected urolithiasis, Faget et al [35] found that the combination of radiograph of the abdomen and pelvis and US enabled identification of 50% of the stones that had been identified via CT, and 68% of the stones treated by urological procedures. Radiography Intravenous Urography There is limited evidence to support the use of radiography with IVU (also referred to as IVP) for initial imaging of patients with symptomatic hydronephrosis with unknown cause. Historically, IVP was used to evaluate hydronephrosis, but this study is considered obsolete in many settings [6]. US Abdomen There is relatively limited evidence to support the use of US of the abdomen for initial imaging of patients with symptomatic hydronephrosis with unknown cause. Although US allows evaluation for increased renal echogenicity, which is nonspecific but can be helpful in assessing for chronic kidney disease, US Abdomen is a less comprehensive examination of the genitourinary system than CT, MRU, renal scintigraphy, or US Color Doppler Kidneys and Bladder Retroperitoneal. US Color Doppler Kidneys and Bladder Retroperitoneal There is substantial literature on the use of US of the kidneys in the setting of renal colic, including for initial imaging of patients with symptomatic hydronephrosis with unknown cause, and it may be useful in this setting in some clinical situations. Although renal US can identify and grade hydronephrosis, it is less useful for identification of etiology. US does allow evaluation for increased renal echogenicity, which, although nonspecific, can be helpful in assessing for chronic kidney disease.
Hydronephrosis on Prior Imaging Unknown Cause. Some of these have shown that combining US findings with complementary KUB improved the sensitivity for urolithiasis and had acceptable specificity when compared with either modality alone [34]. In a prospective study of 206 patients with renal colic and suspected urolithiasis, Faget et al [35] found that the combination of radiograph of the abdomen and pelvis and US enabled identification of 50% of the stones that had been identified via CT, and 68% of the stones treated by urological procedures. Radiography Intravenous Urography There is limited evidence to support the use of radiography with IVU (also referred to as IVP) for initial imaging of patients with symptomatic hydronephrosis with unknown cause. Historically, IVP was used to evaluate hydronephrosis, but this study is considered obsolete in many settings [6]. US Abdomen There is relatively limited evidence to support the use of US of the abdomen for initial imaging of patients with symptomatic hydronephrosis with unknown cause. Although US allows evaluation for increased renal echogenicity, which is nonspecific but can be helpful in assessing for chronic kidney disease, US Abdomen is a less comprehensive examination of the genitourinary system than CT, MRU, renal scintigraphy, or US Color Doppler Kidneys and Bladder Retroperitoneal. US Color Doppler Kidneys and Bladder Retroperitoneal There is substantial literature on the use of US of the kidneys in the setting of renal colic, including for initial imaging of patients with symptomatic hydronephrosis with unknown cause, and it may be useful in this setting in some clinical situations. Although renal US can identify and grade hydronephrosis, it is less useful for identification of etiology. US does allow evaluation for increased renal echogenicity, which, although nonspecific, can be helpful in assessing for chronic kidney disease.