Does a full bladder aid upper tract visualization in magnetic resonance urography?

The aim of this study was to evaluate whether a full bladder improved the visualization of the upper renal tract during magnetic resonance urography (MRU). Twenty volunteers were recruited into the study. The MRU imaging was carried out on a 1.5-T MR system. Imaging was carried out in the coronal plane using a half-Fourier acquired single-shot turbo-spin-echo technique. All volunteers were examined in two separate MRU studies to visualize the urinary tract. The first study was carried out with a 'full' bladder followed by a study with an 'empty' bladder, leading to a total of 40 examinations. Two radiologists then reviewed maximum intensity projection images from both 'full' and 'empty' studies independently. Both left and right upper tracts were divided into five segments. A three-point grading system was used to evaluate visualization. Excellent visualization = 3, good visualization = 2 and poor visualization = 1. Maximum score per patient was 30. Results were tabulated and analysed using an Excel database. The average score for visualization for the 'full' bladder group was 22.1/30 (73.8%) and the average score for the empty bladder was 16.2/30 (54%). Overall improvement in visualization was 5.9/30 (19.8%). There was strong interobserver agreement, with a concordance value of 92.5%. The MRU carried out in healthy young adult volunteers with a full bladder allows improved visualization of the upper tracts.