Identifying recurrent malignant glioma after treatment using amide proton transfer-weighted MR imaging: A validation study with image-guided stereotactic biopsy

Purpose: To quantify the accuracy of amide proton trans-the same tumor. Of the 64 total specimens, 20 specimens were fer-weighted (APTw) MRI for identifying active glioma after active glioma, 27 mixed active and quiescent glioma, and 17 treatment via radiographically guided stereotactic tissue quiescent/no identifiable tumor. APTw signal intensity and validation. histopathologic assignment, cellularity, and proliferation Experimental Design: Twenty-one patients who were index had significant positive correlations (R ¼ 0.651, referred for surgery for MRI features concerning for tumor 0.580, and 0.458, respectively; all P < 0.001). ROC analysis progression versus treatment effect underwent preoperative with a 1.79% APTw intensity cutoff differentiated active from APTw imaging. Stereotactic biopsy samples were taken from nonactive tumor (AUC of 0.881) with 85.1% sensitivity and regions of interest with varying APTw signal intensities. 94.1% specificity. Analysis of clinical pathology showed the The relationship between final clinical pathology and the mean APTw intensity for each patient had 94.4% sensitivity histopathology of each of the 64 specimens was analyzed and 100% positive predictive value for identifying recurrent relative to APTw results. Analysis of confirmed recurrent tumor glioma at this cutoff. or treatment effect tissue was used to perform ROC analysis. Conclusions: APTw imaging hyperintensity may be a mark-Results: Eighteen of 21 patients had recurrent tumor, and 3 er of active malignant glioma. It is able to distinguish between had treatment effect on clinical pathology. In 12 patients, there regions of heterogeneous abnormality on anatomic brain MRI were multiple histopathologic assignments confirmed within with high sensitivity and specificity.