Abstract
BACKGROUND AND PURPOSE: The differential diagnosis of radionecrosis and tumor recurrence in brain metastases is challenging. We investigated the diagnostic efficiency of postcontrast T1 mapping in solving this problem.
MATERIALS AND METHODS: Between March 2016 and June 2017, fifty-six patients with brain metastases who underwent contrast-enhanced cerebral T1 mapping were recruited for this prospective study. The findings revealed new enhancement after gamma knife radiosurgery. The subjects were assigned to radionecrosis and recurrence groups based on follow-up (median, 11.5 months) and histopathologic results. T1 values of lesions 5 (T15min) and 60 (T160min) minutes after administration of contrast agent and their difference (T1differ) were compared between the 2 groups with the 2-tailed Mann-Whitney U test. Receiver operating characteristic curves were used to determine the optimum cutoff values for differential diagnosis.
RESULTS: There were significant differences between the 2 groups in T15min, T160min, and T1differ values (P = .012, P = .004, and P < .001, respectively). Relative to T15min and T160min, T1differ exhibited greater sensitivity and specificity (P < .001, respectively) in identifying radionecrosis. The optimum T1differ value for differential diagnosis was 71.1 ms (area under the curve = 0.97; 95% CI, 0.93–1.00), with sensitivity and specificity of 81.5% and 96.5%, respectively.
CONCLUSIONS: Postcontrast T1 mapping is optimal for the differential diagnosis of radionecrosis and tumor recurrence. Among T1 parameters, T1differ is the most powerful parameter for differential diagnosis. Advantages in terms of quantitative analysis and high resolution portend the wide use of postcontrast T1 mapping in the future.
ABBREVIATIONS:
- AUC
- area under the curve
- BM
- brain metastases
- GKR
- gamma knife radiosurgery
- rCBV
- relative cerebral blood volume
- T15min
- T1 values at 5 minutes after contrast administration
- T160min
- T1 values at 60 minutes after contrast administration
- T1differ
- the difference between T160min − T15min
Footnotes
Disclosures: Yingchao Liu—RELATED: Grant: National Natural Science Foundation of China (81641176), Natural Science Foundation of Shandong Province (ZR20141TM002), Science and Technology Planning Project of Shandong Province (2014GSF118046, 2015GSF118161, 2016GSF201092, and 2017CXGC1209), and Taishan Scholars Program (No. tsqn20161070). Shangchen Xu—RELATED: Grant: Natural Science Foundation of Shandong Province (ZR2014HM069).
We gratefully acknowledge the financial support of the National Natural Science Foundation of China (81641176), the Natural Science Foundation of Shandong Province (ZR2014HM069 and ZR20141TM002), the Science and Technology Planning Project of Shandong Province (2015GSF118161, 2017CXGC1209, 2014GSF118046, and 2016GSF201092), The National Key Research and Development Program (2016YFC0106105). and the Taishan Scholars Program (No. tsqn20161070).
- © 2018 by American Journal of Neuroradiology
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