Single breath‐hold diffusion‐weighted imaging of the abdomen

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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. J. Magn. Reson. Imaging 2003;18:377–382. © 2003 Wiley-Liss, Inc.