Excretory MR Urography Using Breathhold Three-dimensional FISP: Comparison with MR Urography Using HASTE Technique

Abstract

Purpose: To compare the usefulness of gadolinium-enhanced excretory MR urography using breath-hold three-dimensional fast imaging with steady state precession (3-D FISP) with conventional MR urography using the half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequence in the evaluation of obstructive uropathy. Materials and Methods: Twenty-three patients in whom ultrasonography (US) and/or intravenous urography(IVU) revealed signs of urinary obstruction were enrolled in this study. Fifteen were men and eight were women, and their mean age was 54 (range, 21 -80) years. All MR images were obtained using a 1.5-T MR unit. MR urography using the HASTE technique (MRU) and gadolinium-enhanced excretory MR urography using the 3D-FISP technique were performed, and in all cases, reconstructions involved maximum intensity projection. For contrast-enhanced MR urography (CEMRU), images were obtained 3, 5, 20, and 30 minutes after the administration of intravenous contrast media, and for selected cases, additional images were obtained until 24 hours after contrast media injection. For qualitative analysis, two experienced radiologists compared CEMRU and MRU in terms of their diagnostic value as regards the level and cause of urinary obstruction, and morphologic accuracy. In addition, signal to noise ratio (SNR) and contrast to noise ratio (CNR) of the urinary tract at each anatomic level were quantitatively analysed. Results: Quantitative analysis showed that in terms of SNR and CNR of the urinary tract at the level of the mid and distal ureter, CEMRU using 3-D FISP was better than MRU using HASTE (p