Magnetic resonance imaging features and apparent diffusion coefficient of diffuse midline gliomas with H3K27M mutation / 中华神经科杂志

ABSTRACT

Objective:To analyze the magnetic resonance imaging (MRI) features of diffuse midline gliomas with H3K27M mutation, and to quantitatively analyze the changes of apparent diffusion coefficient (ADC).Methods:The MRI images of 14 cases of diffuse midline gliomas with H3K27M mutation were retrospectively analyzed in the Affiliated Hospital of Qingdao University from April 2017 to November 2019. The location, edge, signal, peritumoral edema and enhancement characteristics of the lesions were observed, and the changes of ADC values were analyzed.Results:The tumors were located in thalamus in four cases, pons in six cases, medulla oblongata in two cases and spinal cord in two cases. In seven cases, the tumor was confined to the midline region, of which six cases had clear boundary, seven cases were located in the midline area, but infiltrated into the non midline area at the same time, and six cases had unclear boundary. Basilar artery entrapment was found in all six patients located in pons. Multiple large cystic changes were found in five cases, multiple small cysts in four cases and no cystic changes in five cases. Cystic changes were found in all seven cases of tumors involving the non midline region, of which six cases were located only in the non midline region, and only two of the seven tumors localized in the midline region had small cysts. Hemorrhage was found in four cases. Five cases showed mild heterogeneous enhancement, six cases showed moderate heterogeneous enhancement, two cases showed obvious enhancement, and one case showed no enhancement. There was no edema around the tumor in nine cases and mild edema in five cases. The average edema index was 1.13. The average ADC value of tumor parenchyma in 12 patients was (7.83±0.88)×10 -4 mm 2/s, which was 15.6% lower than that of the contralateral side [(9.28±0.69)×10 -4 mm 2/s, t=-6.336, P<0.05]. Conclusions:Diffuse midline gliomas with H3K27M mutation have a younger onset age and are more likely to occur in thalamus, brainstem and spinal cord. Most of the tumors have no peritumoral edema or mild peritumoral edema. The tumors confined to the midline region are regular in shape and clear in boundary. The masses involving the non midline area are prone to cystic necrosis. Diffuse midline gliomas with H3K27M mutation in pons are prone to basilar artery entrapment. ADC value can provide a quantitative basis for preoperative tumor grading.