In Vitro of MR Imaging of the Resected Normal Gastric Wall: Radiologic-Histologic Correlation

Seo, Bo Kyoung; Seol, Hae Young; Lee, Nam Joon; Cha, In Ho; Chung, Kyoo Byung; Kim, Jung Hyuk; Park, Cheol Min; Choe, Eun Jung; Je, Bo Kyung; Lee, Ji Yung; Lee, Ki Yeoul; Kim, Chung Yeul; Cho, Seong Jin

Abstract

PURPOSE
To evaluate normal human gastric wall layers in vitro using magnetic resonance*(MR) imaging, to correlate the results with the histologic findings, and to determine the optimal technique for evaluation of the gastric wall.
MATERIALS AND METHODS
Forty-one normal resected gastric specimens obtained from 25 patients were dissected and placed in a polyethylene tube filled with normal saline. MR imaging with four MR sequences, T1-weighted FLASH*(T1FLASH), fat-saturated T1-weighted FLASH, T2-weighted TSE*(T2TSE), and True-FISP, was performed. The number of gastric wall layers and signal intensity of each layer were determined, and after correlating MR images with the histologic findings, the conspicuity of each layer*(mucosa, submucosa, and muscle), the distinction between each layer, and overall image quality were assessed.
RESULTS
The gastric wall was shown by TIFLASH to have two (n=6, 14-6%), three (n=31, 75.6%) and four layers (n=4, 9.8%); by fat-saturated TIFLASH to have two (n=6, 14.6%) and three (n=35, 85.4%) ; by T2TSE to have three (n=24, 58.5%), four (n=11, 26.8%), and five (n=6, 14.6%); and by True-FISP to have one (n=2, 4.9%), two (n=8, 19.5%), three (n=23, 56%), four (n=4, 9.8%), and five (n=4, 9.8%) . The signal intensity of each layer at T1FLASH and fat-saturated T1FLASH was high-intermediate from the lumen in two-layer cases, high-low-high/intermediate in three-layer cases, and high-low-high-intermediate in four-layer cases. The signal intensity of each layer at T2TSE was intermediate/high-low-intermediate in three-layer cases, intermediate low-high-intermediate/low in four-layer cases, and low-high-low-high-low in five-layer cases. Three-layered gastric wall corresponded mostly to mucosa, submucosa, and muscle from the inner to outer layers, respectively. T1FLASH, fat-saturated T1FLASH, and T2TSE were superior to True-FISP in evaluating the gastric wall. T1FLASH and fat-saturated T1FLASH were the best sequences for demonstrating mucosa (p<0.05), and T2TSE was the best for submucosa and the distinction between this and muscle (p<0.05). Both T1FLASH and T2TSE provided the best overall image quality (p<0.05).
CONCLUSION
In-vitro MR imaging is an excellent technique for the evaluation of layers of normal gastric wall. T2TSE is the sequence which best demonstrates the conspicuity of submucosa, the distinction between submucosa and muscle, and overall image quality.