Similarly, the crude overall accuracy for diagnosis of urethral strictures was identical with both modalities (85%). The mean stricture length as measured by RUG was 1.5 ± 1.3 and by MR urethrography, 1.2 ± 0.9, with no statistically significant difference between the modalities ( p = 0.25). Strictures with length <1.5 cm were defined as “short strictures,” whereas longer strictures were defined as “long strictures.” In both methods, the total stricture length was measured including the tapered segments on either side of the tight stricture. Processing of the images was done at a separate work station (Advantage window 4.1 General Electric). The reformatted images at different axial, coronal, and sagittal oblique planes were obtained to delineate the entire length of the urethra, characterize the surrounding soft tissue with depth and density of periurethral fibrosis, and define stricture length. Then, sagittal high-resolution T2 imaging of the penis and urinary bladder was performed with the following parameters: TR = 4000–6000 mscc, TE = 80–120 mscc, slice thickness = 2 mm, interslice gap = 0 mm. The MR technique includes injection of sterile gel into the urethra, then application of a soft clamp to the penile tip to keep the urethra distended. Measuring of urethral stricture length at ascending urethrography was done using the Magic View Picture Archiving and Communicating System (PACS General Electric, Milwaukee, WI) after measurement calibration. In cases of posterior urethral distraction defect (PUDD), RUG was combined with a micturition study to measure the defect. The entire length of urethra was assessed for any narrowing or abnormal fistulous communications. RUG was done with the patient placed in a 45° oblique position, with the dependent hip acutely flexed and the penis extended along the soft tissue of the thigh and as parallel to the tibia as possible.
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