Single breath-hold diffusion-weighted imaging of the abdomen

Abstract

Purpose: To generate high quality diffusion-weighted images (DWI) and corresponding isotropic ADC maps of the abdomen with full organ (kidneys) coverage in a single breath-hold. Materials and Methods: DWI was performed in 12 healthy subjects with an asymmetric, spin-echo, single-shot EPI readout on a system with high performance gradients (40 mT/minute). The isotropic diffusion coefficient (D) was measured from (D) maps and SNR was determined for both diffusion-weighted and reference images in the liver, spleen, pancreas, and kidneys. In six patients, single-axis diffusion encoding along three orthogonal axes (12 NEX) was employed to assess anisotropic diffusion in kidneys. Results: This technique yielded images of quality and resolution which compares favorably to that of prior work. SNR ranged from 27.0 in liver to 44.1 in kidneys for the diffusion-weighted images, and from 19.6 in liver to 39.0 in kidneys in reference images. ADCs obtained in the renal medulla, renal cortex, liver, spleen, and pancreas were (2091 ± 55) × 10-6, (2580 ± 53) × 10-6, (1697 ± 52) × 10 -6, (1047 ± 82) × 10-6, and (2605 ± 168) × 10-6 mm2/second, respectively (mean ± SE). Apparent diffusion coefficient (ADC) in the renal medulla and cortex were significantly different by paired t-test (P = 4.22 × 10-10). Renal medulla and cortex yielded anisotropy indices (AI) of 0.129 and 0.067, respectively. Conclusions: 1) Single-shot SE EPI DWI in the abdomen with this technique provides high quality images and (D) maps with full organ coverage in a single breath-hold; 2) ADCs obtained in the renal medulla and cortex are significantly different; and 3) diffusion within the renal medulla is moderately anisotropic. © 2003 Wiley-Liss, Inc.