MR Urography in Patients with Acute Flank Pain: Comparison of Gadolinium-Enhanced 3D FLASH After Low-Dose Diuretic with 2D Turbo Spin Echo Sequences

Introduction: Intravenous excretory urography (IVU) has been regarded as the imaging modality of choice for the detection of urinary tract disorders in patients with acute flank pain. Functional as well as anatomical details are provided by this imaging technique. The use of ionised radiation and contrast material (CM) are considered to be the major drawbacks of IVU. Recently, the use of magnetic resonance urography (MRU) using half-Fourier acquisition single-shot turbo spin-echo (HASTE) and rapid acquisition with relaxation enhancement (RARE) sequences has been described in patients with urinary tract disease. High resolution images can be achieved with breath-hold and rapid acquisition sequences. HASTE and RARE can demonstrate acute urinary obstruction and show perirenal high intensity signal. However, information about renal function is not achieved. Small stones are difficult to detect, and nondilated urinary tract is not fully visualised. In this aspect Gadoliniumenhanced three-dimensional fast low-angle shot (3D FLASH) sequence provides an alternative rapid imaging technique for urinary tract evaluation. The aim of this study was to compare the utility of combined thin slice HASTE and thick slab single-shot turbo spin echo (TSE) sequences with 3D FLASH MRU in the evaluation of patients with acute flank pain.