Differentiation of postoperative recurrent glioma and radiation injury with two-dimensional proton MR spectroscopy / 中国医学影像技术

ABSTRACT

Objective To evaluate the differentiated effectiveness of two-dimensional proton MR spectroscopy (2D~1H-MRS) to post-operative recurrent glioma and radiation injury. Methods Conventional MR and 2D~1H-MRS examinations were performed with Siemens 3.0T MR system for patients with recurrent contrast-enhancing lesions at the site of the treated glioma. The metabolite peaks were measured at the regions of enhanced nodule and edema, including N-acetylaspartate (NAA), choline-containing compounds (Cho) and creatine (Cr), while the Cho/Cr, Cho/NAA, NAA/Cr ratios were calculated. The new lesions were proved with histo-pathologic examination in 23 patients and clinical-imaging following-up in 12 patients. Recurrent gliomas were found in 20 patients, and radiation injury in 15 patients. Each mean metabolite ratio above was compared between two lesion types. Results At contrast-enhancing regions and edema regions, the mean Cho/Cr and Cho/NAA ratios were all significantly higher in patients with tumor recurrence compared with those with radiation injury. Tthe mean NAA/Cr ratio was significantly lower in patients with tumor recurrence compared with that with radiation injury at contrast-enhancing regions, but no significant difference was found at edema regions. Taking Cho/Cr and (or) Cho/NAA ratios >1.77 based on ROC curves of metabolite ratios as standards, the diagnostic sensitivity, specificity and accuracy was 90.00% (18/20), 93.33% (14/15) and 91.43% (32/35), respectively. Conclusion 2D~1H-MRS is a valuable method to distinguish postoperative recurrent glioma and radiation injury.