- Acute pyelonephritis is a common clinical diagnosis in patients who present with fever, chills, and flank tenderness.
- Infections typically result from ascending retrograde spread through the collecting ducts into the renal parenchyma.
- Patients are referred for CT evaluation of acute pyelonephritis when symptoms are poorly localized or complications are suspected.
 Imaging Findings
- Acute pyelonephritis consist of focal areas of striated or wedge-shaped hypoperfusion, resulting in a characteristic striated nephrogram.
- Striations result from stasis of contrast material within edematous tubules that demonstrates increasing attenuation over time.
- The infected kidney is usually enlarged, and there is often stranding in the perinephric fat.
- Delayed views of the infected kidney may demonstrate a nephrogram with increased attenuation.
Patient #1: CT images of a patient with acute pyelonephritis
 See Also
- Chronic pyelonephritis
- Emphysematous pyelonephritis
- Xanthogranulomatous pyelonephritis
- Renal infarction
 External Links
- Bruce A. Urban, and Elliot K. Fishman. Tailored Helical CT Evaluation of Acute Abdomen. RadioGraphics 2000 20: 725-749.