Localized Proton MRS ( 1H Magnetic Resonance Spectroscopy ) for Characterizing Human Uterine Cervical Cancer In Vivo

Kim, Y M; Na, J H; Lee, J H; Cho, K S; Kim, J H; Kim, Y T; Nam, C H; Mok, J E

Abstract

MRS (magnetic resonance spectroscopy) is a recently introduced technique to the gynecologic field which can assess the chemical composition and the metabolic status of tissues of interests. It can identify and quantify the metabolites in the cells and tissues in vivo and in vitro. Its non-invasive nature in the technology attracts clinicians from many fields of medicine; owing to its non-invasiveness, it can be used repeatedly on the same site, which can particularly be useful for monitoring therapeutic response. Additionally, the analysis of MR spectrum is relatively straitforward with high accuracy. The aim of this study is to develop a set of protocol for MR spectroscopy to characterize cervical cancer. Localized 1H in vivo NMR spectra of the human uterine cervix were acquired from 11 patients with invasive cervical squamous cell carcinoma and 3 normal subjects. Image guided PRESS-spectra were obtained on a GE 1.5T SIGNA system equipped with shielded gradients (General Electric Medical System, Milwaukee, USA). Body coil was used for transmitting the signal and an endovaginal surface coil (homebuilt) was placed in the posterior fornix of the vagina. Extent of the cancer invasion was examined prior to the MRS measurement by T1 and T2-weighted surface coil spin-echo MR images. Localized 1H in vivo MR spectra of normal cervix and cervical carcinoma were shown. The spectra were in good agreement with the previous reports of 1H ex vivo NMR studies of cervical biopsies. In the spectra of the cervical carcinoma, the resonance peaks at 0.9, 1.3, 3.0 and 3.2 ppm are from CH3- and CH2-groups of mobile lipid (e.g., triglycerides), creatine and choline containing residues, respectively. The resonance peak at 1.3 ppm which is from CH2 groups of acyl chains in triglyceride is characteristically intense and seen in all the cancer spectra at TE=20 and 135 msec. In contrast, the spectra of the normal cervix did not show any resonance peaks. In conclusion, localized 1H in vivo MRS can be useful to discriminate the cervical carcinoma from normal cervix. The resonance peak at 1.3 ppm which is known to be from CH2 groups of triglycerides can be a marker for the cervical carcinoma.