The impact of magnetic resonance imaging spectroscopy parameters on differentiating between paediatric medulloblastoma and ependymoma

Introduction
The distinction of medulloblastomas and ependymomas plays an important role in the care plans and prognosis of children. We aimed to investigate the role of magnetic resonance spectroscopy (MRS) in the differentiation between medulloblastomas and ependymomas in children.

Material and methods
The institutional review board approved this prospective study. The brain magnetic resonance imaging protocol including axial multivoxel spectroscopy with a TE of 144 ms was assessed in 49 patients, who were divided into 2 groups: 40 patients with medulloblastomas and 9 patients with ependymomas. Receiver operating characteristic (ROC) curve analysis and the Youden index were utilized to determine the best cut-off, sensitivity, specificity, and area under the curve (AUC) values of the independent spectroscopy parameters.

Results
The choline level (Cho) and the choline/creatine (Cho/Cr) and choline/N-acetyl aspartate (Cho/NAA) ratios of medulloblastomas were significantly higher than those of ependymomas (p < 0.05). A Cho/NAA cut-off value of 1.24 to predict the diagnosis of medulloblastoma yielded the highest AUC and sensitivity of 80.3% and 97.5%, respectively, while a Cho cut-off value of 4.64 produced the highest specificity value of 88.9%.

Conclusions
Our findings suggest that Cho and Cho/NAA derived from MRS could serve as differential factors between paediatric medulloblastomas and ependymomas. Among those, a Cho/NAA cut-off value of 1.24 to predict the diagnosis of medulloblastoma generated the highest accuracy.