Low b‐value diffusion‐weighted imaging for diagnosing strangulated small bowel obstruction: A feasibility study

Abstract

Purpose: To assess the feasibility of low b-value diffusion-weighted imaging (DWI) for diagnosing strangulated small bowel obstruction (SBO). Apparent diffusion coefficients (ADCs) and signal preservation ratios (SPRs) were measured in the distal jejunum in the volunteers before and after butylscopolamine administration, and in the (strangulated) closed loop, near the obstructive site, and far from the obstructive site in the patients. Low b-value diffusion-weighted images in the patients were quantitatively evaluated for diagnosing strangulation.Results: In the volunteers, mean ADC (10 À3 mm 2 /s) and SPR (%) before butylscopolamine administration (18.3 6 5.9 and 41.4 6 11.5) were significantly different (P < 0.05) from those after butylscopolamine administration (6.4 6 3.6 and 73.7 6 12.9). In the patients, mean ADCs and SPRs among the strangulated closed loop (3.8 6 2.2 and 83.3 6 9.3), near the obstructive site (12.1 6 6.9 and 57.3 6 18.5), and far from the obstructive site (26.8 6 10.7 and 29.9 6 16.4) were significantly different (P < 0.05). Areas under the receiver operating characteristic curve for the diagnosis of strangulation varied between 0.937 and 1.000.Conclusion: Low b-value DWI is a feasible technique to distinguish the strangulated closed loop from nonstrangulated loops in SBO, and show promise for diagnosing strangulated SBO.

MR Imaging-based Evaluation of Mesenteric Ischemia Caused by Strangulated Small Bowel Obstruction and Mesenteric Venous Occlusion: An Experimental Study Using Rabbits

“…Diagnosing mesenteric ischemia using MRI is challenging in clinical practice because of the absence of clinical research. 22,23 This study assessed the utility of MRI for diagnosing mesenteric ischemia caused by strangulated SBO or MVO. Prior research assessing mesenteric ischemia using MRI was performed in rats, [16][17][18] rabbits, 19,20 and pigs.…”

“…In clinical research, combined sequences with fast low-angle shot and half-Fourier single-shot turbo spin echo (HASTE) clinically provided greater information about the causes of a disease than CT in bowel obstruction, but not in mesenteric ischemia, 29 although cine MRI and low b-value MRI can accurately diagnose mesenteric ischemia by detecting the decreased peristaltic movement of the strangulated small bowel. 22,23 MRI can evaluate mesenteric venous thrombosis by measuring the oxygen desaturation in the superior mesenteric vein or revealing hypomotility of the small intestine. 30 We performed T 1 WIs, T 2 WIs, FS-T 1 WI, and FS-T 2 WIs, which took 30 min of examination time; however, this protocol is not suitable for diagnosis of mesenteric ischemia because acute mesenteric ischemia is required to be diagnosed and treated promptly, and a shorter MRI examination time is desirable.…”

Low b‐value diffusion‐weighted imaging: Emerging applications in the body

“…First, signal of the wall of the (peristaltic) small intestine is usually well maintained at low b‐value DWI (Fig. 4) (52). This suggests that intestinal wall motion can be regarded as linear rigid body motion during the period in which the MPGs for IVIM encoding are applied, as a result of which significant intravoxel phase dispersion and subsequent signal loss do not occur.…”

“…However, if peristalsis is decreased or absent, signal of small bowel contents can be remarkably well preserved at low b‐value DWI (Fig. 4) (52), whereas this is not the case when higher b‐values are applied. Therefore, low b‐value DWI may be used to assess small bowel peristalsis and evaluate conditions in which small bowel peristalsis is reduced or absent.…”

“…Therefore, low b‐value DWI may be used to assess small bowel peristalsis and evaluate conditions in which small bowel peristalsis is reduced or absent. A recent study in 5 healthy volunteers and in 14 patients suspected of having strangulated SBO showed the feasibility of this concept (52). In the volunteers, who were asked to drink green tea to fill the small bowel, signal of the small bowel signal was considerably reduced at a b‐value of 50 s/mm 2 compared with that at a b‐value of 0 s/mm 2 .…”