200 cells in the prostate [1]. BPH may be associated with benign prostatic enlargement (BPE), lower urinary tract symptoms (LUTS) and benign prostatic obstruction (BPO), although no clear correlations among the components have been found so far [2–5]. BPH starts affecting men by their fourth decade and occurs in up to 90% in the ninth decade [6]. It is ranked ﬁfth among the ten most frequently treated diseases in Western countries [7] and responsible for a high socio-economic burden in ageing societies. Intravenous urography (IVU) is a radiological tool for the assessment of BPH-related changes of the upper/lower urinary tract (e.g. hydronephrosis, trabeculation, diverticula and bladder stones) and other urological diseases (e.g. nephro-/ureterolithiasis and upper urinary tract tumours). Despite its excellent diagnostic value, IVU was abandoned for routine work-up of patients with BPH in most Western countries in 1990s due to increased radiation risks, costs, and low additional diagnostic beneﬁt compared to ultra- sonography [8–11]. Nevertheless, IVU remains a valid tool to evaluate upper urinary tract pathology (stones, tumours) and haematuria until today. Therefore, physicians must still be familiar with IVU to properly judge the urinary tract. This study aims to retrospectively investigate clinical and urodynamic data in a cohort of BPH–LUTS patients and correlate them with IVU signs to evaluate a potential asso- ciation with morphological changes of the urinary tract in an attempt to contribute to the pathophysiology of the disease. Materials and methods Inclusion and exclusion criteria During 1st January and 31st December 1994, all men aged C45 years with BPH–LUTS referred to the Department of Urology, Hannover Medical School were systematically investigated according to the department policy with (a) medical history focusing on LUTS, (b) physical (digito- rectal) examination, (c) International Prostate Symptom Score (IPSS), (d) urinalysis, (e) laboratory tests including prostate speciﬁc antigen and creatinine levels, (f) trans- rectal prostate ultrasound (TRUS), (g) free uroﬂowmetry and measurement of postvoid residual (PVR) urine, (h) multi-channel computer-urodynamic investigation (UDI), and (i) intravenous urography (IVU). Men with an indwelling bladder catheter, impaired renal function (serum-creatinine [180 lmol/l), known bladder stones/diverticula, or allergy to iodine contrast media received a reduced work-up (a–f). Men with a neurological deﬁcit, previous lower urinary tract or pelvis operations, known prostate or transitional cell cancer, or 5a-reductase inhibitors were excluded. Only men with a complete work- up (a–i) were included in the study. 123 World J Urol (2011) 29:199–204 Assessment protocol All investigations were performed as outpatient procedures during two visits. Medical history, physical examination, urine as well as blood samples were taken. TRUS was performed with a 7.5 MHz array and prostate volume was determined by measuring the greatest transverse and lon- gitudinal dimensions. Free uroﬂowmetry was done when the patient reported a full bladder; a minimal voided urine volume of 150 ml was considered acceptable to judge maximum urinary ﬂow rate (Qmax). PVR was measured immediately after voiding using a 3.5 MHz ultrasound array measuring the greatest bladder transverse and longi- tudinal distances. Free uroﬂowmetry and PVR measure- ments were repeated at least once and the highest Qmax/ lowest PVR were used for analysis. Patients were asked to complete the IPSS questionnaire and deliver their answers at the second visit. IVU and UDI were performed one to 3 weeks after initial presentation if renal function and urinalysis were appropriate. Three IVU images were taken in the lying position; the ﬁrst before and the second and third ﬁve and 15 min after contrast media infusion (100 ml SolutrastTM 300), respectively. UDI was performed using a 7F transu- rethral microtip and a 12F rectal catheter. The bladder was ﬁlled with physiological saline solution of 37 C at a rate of 25–50 ml/min. Methods, deﬁnitions and units were in line with the International Continence Society recommenda- tions [1]. UDI were conducted at least twice and the lowest degree of BPO, based on the Scha¨fer classiﬁcation [12], was used for analysis. Evaluation of morphological and functional signs Structural alterations of the urinary tract on IVU were correlated with clinical and urodynamic data using logistic regression analysis. We focused on the following binary dependent variables based on IVU ﬁndings (Fig. 1): (a) urinary tract calciﬁcations, (b) delayed excretion of con- trast media, (c) upper urinary tract dilatation of any degree, (d) peristalsis of the ureter(s), (e) uni- or bilateral ‘‘ﬁsh- hook’’ conﬁguration of the distal ureter (‘‘hockey-stick’’ or ‘‘J-shaped’’ ureter), (f) delayed emptying of the ureter(s), (g) bladder base elevation of any degree, (h) bladder diverticula unknown prior to investigation and/or trabeculation. The following urodynamic variables were tested as potential predictors of the dependent variables (univariable analysis): (a) normal/low bladder compliance, (b) presence/ absence of detrusor overactivity, (c) amplitude of unin- hibited detrusor contractions in patients with detrusor overactivity, (d) presence/absence of detrusor overactivity incontinence, (e) normal/week detrusor work during