Diagnostic impact of proton MR-spectroscopy versus image-guided stereotactic biopsy

Summary Background. The aim of this study was to compare the diagnostic accuracy of ¹H MR-spectroscopy versus image-guided stereotactic biopsy. Method. A cohort of 83 consecutive patients with a broad spectrum of brain lesions were examined. Prior to stereotactic biopsy, the patients were subjected to ¹H MR-spectroscopy examination. Diagnostic accuracy of ¹H MR-spectroscopy and image guided stereotactic biopsy was determined for the largest diagnostic subgroups. Each diagnostic procedure was tested for concordance in every subgroup. Findings. The subgroups of patients comprised: low grade glioma, high grade glioma (grades III and IV), lymphoma and metastasis. For the sensitivity of ¹H MR-spectroscopy ranged from 87.7 in high grade glioma to 92.3% in metastasis and for specificity from 93.3% for high grade glioma to 100% in low grade glioma. The highest positive predictive value of 100% was reached in the subgroup of low grade glioma. The highest negative predictive value was reached in lymphoma and metastasis, 100%. The kappa values were highly significant for all comparisons (p<0.001). The co-efficient ranged from 0.68 to 0.84. It was lowest in assessing high grade glioma and highest in lymphoma. Conclusion. Compared with each other ¹H MR-spectroscopy and image-guided stereotactic biopsy showed a moderate to good, statistically highly significant concordance. In patients in whom operation is at an increased risk e.g., due to severe medical illness, ¹H MR-spectroscopy as a noninvasive procedure may be sufficient to assess the diagnosis.