Diagnostic performance of multiparametric MRI in the evaluation of treatment response in glioma patients at 3T

Background: MRI is one of the most important techniques to assess the treatment response of gliomas. However, differentiating tumor recurrence (TuR) from treatment effects (TrE) remains challenging.

Purpose: To compare the diagnostic performance of MR diffusion-weighted imaging (DWI), arterial spin labeling (ASL), proton MR spectroscopy (MRS), and amide proton transfer (APT) imaging in differentiating between TuR and TrE in posttreatment glioma patients.

Study type: Prospective.

Population: Thirty patients with suspected tumor progression.

Field strength/sequence: DWI, ASL, proton MRS, and APT imaging were performed at 3T MR.

Assessment: MR indices, including ADC, relative cerebral blood flow (rCBF), ratios of Cho/Cr, Cho/NAA, and NAA/Cr and APT-weighted (APTw) effect were obtained from DWI, ASL, proton MRS, and APT imaging, respectively. Indices were measured in the contralateral normal-appearing white matter and lesions defined on the Gd-enhanced T₁ w image. TuR or TrE was either determined histologically or clinically from longitudinal MRI follow-up for at least 6 months.

Statistical tests: The diagnostic performance of the indices was evaluated using Student's t-test, receiver operating characteristic (ROC) curve, and multivariate logistic regression analyses.

Results: Among the 30 patients, 16 were diagnosed as having TuR and the rest having TrE. The recurrent tumors showed a significantly higher APTw effect (1.56 ± 1.14%) and rCBF (1.44 ± 0.61) compared with lesions representing treatment effects (-0.44 ± 1.34% and 0.72 ± 0.25, respectively, with P < 0.001). The areas under the curve (AUCs) were 0.87 and 0.90 for APTw and rCBF, respectively, in differentiating between TuR and TrE. Combining APTw and rCBF achieved a higher AUC of 0.93. MRS index ratios of Cho/Cr (P = 0.25), Cho/NAA (P = 0.16), and NAA/Cr (P = 0.86) and ADC (P = 0.37) showed no significant differences between TuR and TrE lesions, with AUCs lower than 0.70.

Data conclusion: Compared with DWI and MRS, ASL and APT imaging techniques showed better diagnostic capability in distinguishing TuR from TrE.

Level of evidence: 1 Technical Efficacy: Stage 4 J. Magn. Reson. Imaging 2020;51:1154-1161.