Imaging Studies for Pyelonephritis

Benefits of Including the Pelvis in Imaging Studies

The American College of Radiology recommends including the pelvis in imaging studies to detect stones in the distal ureters or urinary bladder that may be the underlying cause of pyelonephritis 2, 3
Including the pelvis facilitates the identification of congenital anomalies of the distal ureters and abnormal insertion sites that may predispose to recurrent infections 2, 4
It allows for the evaluation of urinary bladder abnormalities that could be potential sources of acute pyelonephritis 1, 2
The American College of Radiology suggests that including the pelvis provides a comprehensive evaluation of the entire genitourinary tract, which is crucial for diagnosis and management 2, 3

Studies limited to the abdomen do not permit a complete evaluation of the genitourinary tract 2, 5
The lack of inclusion of the pelvis may lead to missed opportunities for detecting urolithiasis in the distal ureters or bladder 6, 2
Congenital anomalies of the distal ureters and abnormal insertion sites may go undetected 1, 2
Pathologies of the bladder that could be sources of ascending infection may not be identified 2, 4

The American College of Radiology recommends CT of the abdomen and pelvis with intravenous contrast as the study of choice for complicated patients with suspected pyelonephritis 3, 7
CT without contrast has high accuracy for detecting kidney stones, while CT with contrast improves the detection of parenchymal changes of pyelonephritis, renal abscesses, and acute extrarenal conditions 3, 4
Including the pelvis in CT is fundamental for detecting potential pelvic anomalies, including urolithiasis in the distal ureters or bladder 2, 3

MRI of the abdomen and pelvis can be useful for detecting pyelonephritis, scars, congenital anomalies, renal abscesses, hydronephrosis, and pyonephrosis 1, 6
MRI has limited accuracy for detecting small urothelial stones and reduced capacity for detecting gas in emphysematous pyelonephritis 1, 5
MRI of the abdomen without including the pelvis does not permit a complete evaluation of the genitourinary tract 6, 5

US with color Doppler that includes the kidneys, bladder, and retroperitoneum can increase sensitivity for detecting pyelonephritis 1, 4
Including the bladder in US could identify other anomalies contributing to pyelonephritis 1, 7

In pregnant patients, MRI of the abdomen and pelvis is generally safe and can be useful for detecting pyelonephritis without exposing the fetus to ionizing radiation 8
In patients with a history of kidney stones or renal obstruction, evaluation of the pelvis is particularly important for identifying the underlying cause 2, 7