Adult women with predisposing factors suspicious for vesicoureteral reflux may also benefit from VCUG [26]. However, VCUG is likely of limited benefit in the acute setting. MRI Abdomen and Pelvis MRI of the abdomen without or with IV contrast may be useful for detecting and characterizing congenital anomalies of the kidneys, and imaging of the pelvis could improve detection of congenital abnormalities of the distal ureters and abnormalities of the urinary bladder. In general, MRI of the pelvis is usually not combined with MRI of the abdomen unless an MRU is being performed. Diffusion-weighted imaging (DWI) [20] and contrast- Acute Pyelonephritis enhanced MRI have similar benefits in detecting renal abnormalities [27]. Studies in adults have shown that DWI can be useful in the diagnosis of uncomplicated pyelonephritis [28-30]. APN, renal abscesses, and pyonephrosis have lower apparent diffusion coefficient (ADC) values than normal renal cortical parenchyma [28]. As such, DWI and ADC provide a viable alternative to contrast-enhanced MRI or CT [30]. Disadvantages of MRI includes relatively poor accuracy for detection of urolithiasis and relatively reduced ability to detect gas in emphysematous py elonephritis [31,32] . Similar to CT, MRI does not provide benefit early in uncomplicated cases [8,14]. MRI Abdomen MRI of the abdomen has high accuracy for the diagnosis of APN in a complicated patient but does not allow for a comprehensive assessment of the entire genitourinary tract. Failure to include the pelvis could lead to a missed opportunity to detect urolithiasis in the distal ureters or urinary bladder, congenital abnormalities of the distal ureters and abnormal ureteral insertion sites, and abnormalities of the urinary bladder, among other potential sources of APN. MRU The excretory phase of MRU does not confer additional benefit with respect to detection and characterization of APN in a complicated patient.
Acute Pyelonephritis. Adult women with predisposing factors suspicious for vesicoureteral reflux may also benefit from VCUG [26]. However, VCUG is likely of limited benefit in the acute setting. MRI Abdomen and Pelvis MRI of the abdomen without or with IV contrast may be useful for detecting and characterizing congenital anomalies of the kidneys, and imaging of the pelvis could improve detection of congenital abnormalities of the distal ureters and abnormalities of the urinary bladder. In general, MRI of the pelvis is usually not combined with MRI of the abdomen unless an MRU is being performed. Diffusion-weighted imaging (DWI) [20] and contrast- Acute Pyelonephritis enhanced MRI have similar benefits in detecting renal abnormalities [27]. Studies in adults have shown that DWI can be useful in the diagnosis of uncomplicated pyelonephritis [28-30]. APN, renal abscesses, and pyonephrosis have lower apparent diffusion coefficient (ADC) values than normal renal cortical parenchyma [28]. As such, DWI and ADC provide a viable alternative to contrast-enhanced MRI or CT [30]. Disadvantages of MRI includes relatively poor accuracy for detection of urolithiasis and relatively reduced ability to detect gas in emphysematous py elonephritis [31,32] . Similar to CT, MRI does not provide benefit early in uncomplicated cases [8,14]. MRI Abdomen MRI of the abdomen has high accuracy for the diagnosis of APN in a complicated patient but does not allow for a comprehensive assessment of the entire genitourinary tract. Failure to include the pelvis could lead to a missed opportunity to detect urolithiasis in the distal ureters or urinary bladder, congenital abnormalities of the distal ureters and abnormal ureteral insertion sites, and abnormalities of the urinary bladder, among other potential sources of APN. MRU The excretory phase of MRU does not confer additional benefit with respect to detection and characterization of APN in a complicated patient.