To describe CT imaging appearance of acute and chronic pyelonephritis and its complications, with key features for early diagnosis.

The diagnosis of urinary tract infections is usually based on clinical data and laboratory tests like urine and blood examinations [1]. Imaging is not required in patients with uncomplicated pyelonephritis who respond to treatment [1]. Imaging assessment may be necessary in high-risk patients or in patients not responding to antibiotics and in detecting complications of pyelonephritis [2]. CT is the best imaging modality used for diagnosis and evaluation of severity of acute pyelonephritis and its complications [3]. Unenhanced CT is useful to reveal calculi, hemorrhage,...

The recommended CT protocol for renal infections includes a nephrographic phase and an excretory phase if there is obstruction [4]. Acute pyelonephritis: Focal form Unenhanced CT scan can shows calculi, gas, hemorrhage, calcifications, obstruction, renal enlargement (Fig.1) and inflammatory masses. Rarely CT may demonstrate some hyperdense areas in hemorrhagic bacterial nephritis, for the presence of bleeding parenchyma [5]. However, oftentimes kidneys appear normal on unenhanced scan [1] and intravenous contrast agent injection is needed to demonstrate acute nephritis (Fig. 2) [5]. On parenchymal phase, focal...

The identification and characterization of the most important CT features of acute and chronic pyelonephritis is crucial for emergency and abdominal radiologists for appropriate patient management.

Dr. Diana Patti email: [email protected] Dr. Federica Vernuccio email: [email protected] Dr. Roberto Cannella email: [email protected] Dr. Giorgia Porrello email: [email protected] Dr. Giuseppe Salvaggio email: [email protected] Prof. Massimo Midiri email:[email protected] The authors declare that they have no conflict of interest. Section of Radiology, BIND, University of Palermo.

1. Browne RFJ et al Imaging of urinary tract infection in the adult. Eur Radiol. (2004) 14:E168-E183. 2. Kawashima A et al CT of renal inflammatory disease. Radiographics (1997) 17:851–866. 3. Chandan J Das, et al Multimodality imaging of renal inflammatory lesions. World J Radiol (2014) 6:865–873. 4. Stunell H, et al Imaging of acute pyelonephritis in the adult. Eur Radiol. (2007) 17:1820-1828. 5. William D. Craig, et al Pyelonephritis: Radiologic-Pathologic Review Radiographics. (2008) 28:255–276. 6. Kawashima A, et al Renal inflammatory disease: the current...