British Journal of Urology (1998), 81, 360–363 The role of power Doppler ultrasonography in the diagnosis of acute pyelonephritis M.E. SAKARYA, H. ARSLAN, R. ERKOC ¸*, M. BOZKURT and M.K. ATILLA† Departments of Radiology, *Nephrology and †Urology, Faculty of Medicine, Yu ¨zu ¨nce ¨ Yil University, Van, Turkey Objective To assess the ability of power Doppler ultra- detected by CT in six, whereas a matching defect was detected on PDU in five, with PDU failing to detect an sonography (PDU) to detect acute pyelonephritis and to compare the findings from PDU with those from infective focus in one. Multifocal diCuse pyelonephritis was diagnosed correctly by enhanced CT and PDU in enhanced computed tomography (CT). Patients and methods Eleven patients (mean age two patients. Conclusion Power Doppler ultrasonography had an 18.5 years, range 5–37) admitted to hospital with a clinical diagnosis of pyelonephritis were assessed with overall sensitivity of 88% and complete specificity in the evaluation of patients with acute pyelonephritis. PDU and enhanced CT, the latter providing the refer- ence method. Keywords Doppler ultrasonography, pyelonephritis, kidney Results The imaging studies showed normal findings in three patients; a single focus of pyelonephritis was culture). Eleven patients (eight female and three male, Introduction mean age 18.5 years, range 5–37) were evaluated pro- spectively and although seven patients presented with When a patient presents with fever, chills, flank pain and a focal mass or diCusely enlarged kidney as revealed symptoms attributable to the urinary tract (dysuria or flank pain), four presented only with fever or signs of by IVU, inflammatory disease must be strongly suspected. Various terms have been used to describe this clinical sepsis that prompted the investigation of the urinary tract. Ultrasonography was performed by two experienced entity, including pyelonephritis (acute, focal or suppurat- ive), acute bacterial nephritis (focal or diCuse) and acute radiologists using the SSA Toshiba 270A scanner (Toshiba Corp, Japan) modified to colour-encode the lobar nephronia [1–4]. The findings on imaging are considered to arise through interstitial oedema and power Doppler signal. A 3.75 MHz high-resolution curved-array transducer and a colour video printer intense vasoconstriction that may be ‘patchy’ with a lobar distribution [5,6]. Colour Doppler ultrasonography (Mitsubishi CP15E, Tokyo, Japan) were used to record representative power Doppler ultrasonograms on colour- has shown promise in detecting acute pyelonephritis, by visualizing abnormal areas of hyper- or hypovascularity print film. The standard examination of the kidney included multiple coronal longitudinal and transverse [7]. Focal areas of decreased perfusion can be detected easily by power Doppler ultrasonography (PDU). In the sections. When necessary, scanning was carried out with the patient prone to visualize the renal parenchyma present study, we aimed to assess the ability of PDU to detect acute pyelonephritis and to compare the findings adequately. A pulse-repetition frequency of 35–45 kHz was used with appropriate adjustments of colour gain on PDU with those from enhanced CT. (from 90 to 100 dB) and wall filter settings (from 57 to 100 Hz). Each PDU examination lasted 20–25 min. The Patients and methods PDU study was interpreted as normal if the perfusion of the renal parenchyma was symmetrical at comparable Between June 1996 and February 1997, 11 patients with acute pyelonephritis were examined using PDU depths on both the long and short axes. Acute pyelo- nephritis was diagnosed if the kidney showed a focus within 24 h of admission to hospital. Acute pyelonephri- tis was diagnosed from a clinical examination (flank with decreased cortical perfusion compared with the other portions of the same kidney at the same depth; no pain, dysuria, fever, signs of sepsis) and laboratory tests (pyuria, raised white cell count and verified urine attempt was made to compare the perfusion pattern to that of the contralateral kidney. Contrast-enhanced CT was performed in all patients Accepted for publication 11 November 1997 360 © 1998 British Journal of Urology