Ex vivo proton MR spectroscopy (1H-MRS) for evaluation of human gastric carcinoma.
The present study was performed to determine the characteristics of the biochemical metabolites related to gastric cancer using ex vivo (1)H magnetic resonance spectroscopy (MRS), and to assess the clinical usefulness. A total of 35 gastric specimens resected during surgery for gastric cancer were used to compare MR spectra. A 1.5-T (64-MHz) clinical MR imager equipped with facilities for spectroscopy was used to obtain MR spectra from 33 gastric specimens. High-resolution (1)H nuclear magnetic resonance (NMR) spectra of the remains of two specimens were also examined with a 9.4-T (400-MHz) NMR spectrometer. Localized spectroscopic measurements were performed in two layers of gastric tissue, the proper muscle layer and the composite mucosa/submucosa layer. T(2) FSE and 3D SPGR images were used to determine the voxel size and the location for MRS data collection. MR spectra were obtained using the single-voxel PRESS technique with parameters of TR/TE = 2000/30 ms, NA = 256, and voxel size = 3 x 3 x 3 mm(3) (27 microL). Cancerous and noncancerous gastric tissues in the voxel were determined by histopathological analysis. On 9.4-T ex vivo NMR spectroscopy, the following metabolite peaks were found: lipids at 0.9 ppm (CH(3)) and 1.3 ppm (CH(2)); alanine (beta-CH(3)) at 1.58 ppm; N-Acetyl neuraminic acid (NANA: sialic acid) at 2.03 ppm; and glutathione at 2.25 ppm in normal gastric tissue layers. In the 1.5-T MR system, broad and featureless spectral peaks of the various metabolites in normal human gastric tissue were observed at 0.9 ppm, 1.3 ppm, 2.0 ppm, and 2.2 ppm regardless of gastric tissue layer. In specimens (Borrmann type III) with tubular adenocarcinoma, resonance peaks were observed at 1.26 ppm, 1.36 ppm (doublet of lactate), and 3.22 ppm (choline). Cancer lesions showed decreased levels of lipid peaks, showing the significant lactate doublet peaks, and increased intensity of the choline peak as compared with noncancerous gastric tissue. We found that decreased levels of lipids and increases in lactate and choline peaks in gastric tissue were markers for malignancy in gastric lesions. Information provided by ex vivo (1)H MRS, together with the development of in vivo (1)H MRS with high field strength and high resolution, may be very useful for the diagnosis of gastric cancer in clinical situation.
Mun
Chi-Woong
CW
Department of Biomedical Engineering, Inje University, Kyongnam, South Korea. mcw@bse.inje.ac.kr
Cho
Ji-Youn
JY
Shin
Woon-Jae
WJ
Choi
Ki-Seung
KS
Eun
Choong-Ki
CK
Cha
Seong Sook
SS
Lee
Junghee
J
Yang
Young Il
YI
Nam
Sang-Hee
SH
Kim
Jeongkoo
J
Lee
Soo Yeol
SY
D000230:Adenocarcinoma / Q000175:diagnosis / Q000378:metabolism* / Q000473:pathology*; D000409:Alanine / Q000378:metabolism; D002794:Choline / Q000378:metabolism; D005240:Feasibility Studies; D006801:Humans; D050356:Lipid Metabolism; D009682:Magnetic Resonance Spectroscopy; D019158:N-Acetylneuraminic Acid / Q000378:metabolism; D009361:Neoplasm Invasiveness; D011522:Protons; D013274:Stomach Neoplasms / Q000175:diagnosis / Q000378:metabolism* / Q000473:pathology*
D011522:Protons; D019158:N-Acetylneuraminic Acid; D002794:Choline; D000409:Alanine