Original article Accurate topographical diagnosis of urinary tract infection in male patients with 111 indium-labelled leukocyte scintigraphy M. Velasco a, * , J.J. Mateos b , J.A. Martinez a , A. Moreno-Martinez a , J.P. Horcajada a , M. Barranco a , F. Lomen ˜a b , J. Mensa a a Instituto Clı ´nico de Enfermedades Infecciosas y Siste ´micas, Barcelona, Spain b Servicio de Medicina Nuclear, Hospital Clı ´nic, C/ Villarroel 170, 08036 Barcelona, Spain Received 14 April 2003; received in revised form 29 December 2003; accepted 23 January 2004 Abstract Background: Although the clinical diagnosis of urinary tract infection (UTI) is straightforward, the precise localization of the urogenital organ affected by the infection is often difficult to establish. Methods: To evaluate this, we prospectively studied 20 males with a clinical diagnosis of acute pyelonephritis (APN), acute prostatitis (AP) and febrile UTI (FUTI), as well as seven control females with APN. 111 Indium-labelled leukocyte scintigraphy (ILS) was performed during the febrile episode and repeated when patients were free of symptoms. Results: ILS showed an abnormal uptake in a urinary organ in every case. All patients with AP showed uptake in the pelvic area. Four male patients presented AP, one of them had uptake in the lumbar area, one in the lumbar and pelvic area, and two in the area of the prostate only. Six out of seven patients with FUTI presented uptake in the pelvic area. All female patients showed kidney uptake. After the clinical resolution of the UTI, no residual uptake was found in any case except for one. Conclusions: These results suggest that ILS is very useful in localizing the affected organ in febrile UTI. Most male patients with a febrile UTI presented a prostatic involvement, suggesting that many cases of APN or FUTI in males may actually be cases of AP not recognized by standard clinical evaluation. D 2004 Elsevier B.V. All rights reserved. Keywords: Urinary tract infection; Diagnosis; Radionuclide imaging 1. Introduction Urinary tract infections are among the most prevalent disorders. Although they are a very common problem, controversy about their diagnosis remains. While the clin- ical diagnosis of urinary tract infection (UTI) is straightfor- ward, the precise localization of the urogenital organ affected by the infection is often difficult to establish [1]. Standard radiographic imaging, such as renal ultrasound and excretory urography, is usually helpful in determining structural abnormalities, but may fail to establish the diag- nosis of the infected organ [2]. Despite a wide variety of diagnostic tools, at present there is no method to localize the infected tissue in male patients. The sensitivity of renal computed tomography and magnetic resonance imaging is higher than that of abdominal ultrasound, but their wide- spread use is impractical [3]. Transrectal ultrasonography has not shown a very high sensitivity for the diagnosis of acute prostatitis [4]. 67 Gallium has traditionally been used to detect focal infection, although its low specificity and intestinal excre- tion decrease its utility in diagnosing prostatitis or pyelone- phritis [5]. 99 mTc-HMPAO-labeled leukocytes have a higher sensitivity and specificity, but unfortunately they also have a high intestinal and renal excretion. 111 Indium-labelled leu- kocyte scintigraphy (ILS) has shown a high sensitivity and specificity in diagnosing the source of infection [6]. Its lack of intestinal or renal excretion during the first 72 h may be especially useful in diagnosing such urinary tract infections as prostatitis or pyelonephritis. Our goal in this study was to evaluate the potential usefulness of ILS in the detection of affected parenchyma in febrile UTI in male patients. 0953-6205/$ - see front matter D 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.ejim.2004.01.020 * Corresponding author. Present address: Seccio ´n de Infecciosas. A ´ rea de Medicina. Fundacio ´n Hospital Alcorco ´n. c/Budapest 1. 28922 Madrid, Spain. Tel.: +34-91-621-9513; fax: +34-91-621-9905. E-mail address: mvelasco@fhalcorcon.es (M. Velasco). www.elsevier.com/locate/ejim European Journal of Internal Medicine 15 (2004) 157 – 161