Proton MR spectroscopy of intracranial lesions with ring-like enhancement

Objective To analyze 1H MRS features of intracranial lesions with ring-like enhancement, and to evaluate the relation between 1H MRS and pathohistological type. Methods A total of 55 cases including glioblastoma ( n =17), metastasis ( n =19), radiation necrosis ( n =11) and brain abscess ( n =8) were analyzed. Two VOIs (the center of lesion and the whole lesion) were acquired by single-voxel PRESS sequence. Results ① glioblastoma: dominant Lip peak was showed in the center of lesion or the whole lesion in 3 cases, and dominant Lac peak was found in 14 cases. Cho/Cr in the center of lesion was 1.80±0.17 (0.57-3.47), while 4.17±0.26 (2.03-8.57) in whole lesion ( P = 0.001 ). NAA peaks was detected in the center of lesion in 13 cases (76.5%). ② metastasis: dominant Lip peak was detected in 11 cases (57.9%), and dominant Lac peak in 8 cases. Cho/Cr in the center of lesion was 1.08±0.24 (0.68-2.71), and 3.62±0.38 (1.02-7.19) in whole lesion ( P =0.031). NAA peaks was detected in the center of lesion in 5 cases (26.3%). ③ radiation: Cho/Cr in the center of lesion was 1.67±0.32 (0-2.12), and 2.13±0.33 (1.08-3.59) in the whole lesion ( P =0.334). Cho/Cr was distinctly different between gliobalstoma or metastasis and radiation necrosis. ④ brain abscess: Lac peaks was detected in 8 cases, AA peaks in 7 cases, Ace peaks in 5 cases, Suc peaks in 3 cases, Ala peaks in 2 cases, Lip peak in 1 case, and Cho and NAA peak in 1 case. Conclusion 1H MRS is able to obtain pathohistological data about intracranial lesions with ring-like enhencement. High Cho/Cr can differentiate neoplasms from non-neoplasms. NAA peak detected in the center of lesions is cue for gliobastoma. AA peak is characteristic of brain abscess.