Usefulness of apparent diffusion coefficient value and proton magnetic resonance spectroscopy as a noninvasive techniques in recurrent cerebral gliomas

Objective

Conventional MRI does not provide sufficient information to differentiate post-radiotherapy necrosis from brain tumor recurrence, recent studies have investigated the use of more advanced imaging modalities that are able to differentiate between the two entities.

Aim of the study

To assess the usefulness of combined apparent diffusion coefficient (ADC) value and single voxel spectroscopy (SVS) in the differentiation between recurrent brain gliomas and post-radiotherapy necrosis.

Methods

Twenty-two patients with suspected tumor recurrence after surgical resection and radiotherapy treatment were included in our study. MRI with contrast, diffusion weighted MRI with ADC value and MR spectroscopy were done to all patients.

Results

ADC values were ≤1.150?×?10^?3?mm²/sec for recurrent high grade gliomas, >1.150–≤1.370?×?10^?3?mm²/sec for recurrent low grade gliomas and >1.370?×?10^?3?mm²/sec for post radiation necrosis. NAA/Cr ratio could significantly differentiate between recurrent gliomas and post radiation necrosis (p value?=?.019), also Cho/Cr was significant p value?=?.006. Also NAA/Cr and Cho/Cr were statistically significant in differentiating recurrent high grade from low grade gliomas (p value?

Conclusion

Combination of calculated ADC value and MR spectroscopy added more information and increase the accuracy of conventional MR imaging in the differentiation of patients with suspected recurrent brain glioma from post-radiotherapy necrosis.