Acute pyelonephritis: comparison of diagnosis with computed tomography and contrast-enhanced ultrasonography.
OBJECTIVE
To assess the value of contrast-enhanced ultrasonography (US) with the contrast pulse-sequence (CPS) technique for detecting renal parenchymal changes in acute pyelonephritis (APN), compared with contrast-enhanced computed tomography (CT) as the reference standard.


METHODS
We examined 100 patients (82 women, 18 men; mean age 30.2 years, range 18-67); children (those aged <18 years) were excluded from the study. All patients had clinical symptoms suggestive of APN. For the US a Sequoia 512 (Acuson, Mountain View, CA, USA) unit including Cadence CPS technology, with a 6C2 probe, was used. A bolus of a 2.4-mL US contrast agent SonoVue (Bracco, Milan, Italy) was injected. For CT a multislice 16-row unit was used (Sensation 16, Siemens, Erlangen, Germany), at a table speed of 2.5 mm/s and a slice thickness of 3 mm; 100 mL of intravenous iodinated contrast agent (flow 3 mL/s) was injected.


RESULTS
On contrast CT, 84 patients (84%) had renal parenchymal changes suggestive of APN; on contrast US, 82 of the 84 (98%) showed renal parenchymal changes, and APN was correctly diagnosed. Seventy-six patients (90%) had unilateral and eight (10%) had bilateral APN, and in two (2%) with APN the diagnosis could not be confirmed by US/CPS (false-negative). No false-positive findings were detected on US/CPS, which had a sensitivity of 98%, a specificity of 100%, a positive predictive value of 100%, and a negative predictive value of 89%.


CONCLUSIONS
CPS/US is accurate for detecting parenchymal changes in APN; it is very sensitive and specific, and allows small renal parenchymal changes to be detected with no radiation exposure.
Mitterberger
Michael
M
Department of Urology, University of Innsbruck, Innsbruck, Austria. michael.mitterberger@uibk.ac.at
Pinggera
Germar M
GM
Colleselli
Daniela
D
Bartsch
Georg
G
Strasser
Hannes
H
Steppan
Ilona
I
Pallwein
Leo
L
Friedrich
Aigner
A
Gradl
Johann
J
Frauscher
Ferdinand
F
D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D015331:Cohort Studies; D003287:Contrast Media; D005188:False Negative Reactions; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011704:Pyelonephritis / Q000000981:diagnostic imaging*; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography / Q000379:methods / Q000592:standards*
D003287:Contrast Media