Poster Presentation 50th International Society for the Study of the Lumbar Spine Annual Meeting 2024

Diagnostic identification of intradural extramedullary spinal tumor on quantitative MRI (#154)

Toshio Nakamae 1 , Naosuke Kamei 1 , Toshiaki Maruyama 1 , Kazuto Nakao 1 , Fadlyansyah Farid 1 , Hiroki Fukui 1 , Nobuo Adachi 1
  1. Hiroshima University, Hiroshima, HIROSHIMA, Japan

Introduction.

Schwannoma and meningioma are the most common intradural extramedullary spinal tumors, but cases are often difficult to differentiate on MRI. The purpose of this study was to investigate the differentiation between schwannomas and meningiomas using MRI quantitative assessment with contrast ratio.

Methods.

Surgical procedures were performed on intradural extramedullary spinal tumors, and cases diagnosed with schwannomas or meningiomas through pathological examination were included. Gender, age, and the location of the tumors were investigated. In addition, regions of interest were set for the entire spinal tumor on the slice where the tumor was the largest in MRI T2 sagittal images. The MRI signal intensity of the spinal tumor (SItumor) was measured, and the contrast ratio (CR) with the MRI signal intensity of the normal spinal cord (SIcord) was calculated (CRtumor=(SItumor-SIcord)/(SItumor+SIcord)). Statistical analysis used the Mann-Whitney U test for intergroup comparisons, with p < 0.05 considered statistically significant. Furthermore, a cutoff value was calculated using the receiver operating characteristic (ROC) curve.

Results.

The study included 50 patients (23 males and 27 females) with an average age of 61.5 years (ranging from 11 to 85 years). Pathologically, there were 33 patients with schwannomas and 17 patients with meningiomas. The tumor locations for schwannomas were 7 patients in the cervical spine, 11 patients in the thoracic spine, and 15 patients in the lumbar spine. For meningiomas, there were 4 patients in the cervical spine and 13 patients in the thoracic spine. CRtumor had a mean of 0.304 (range: 0.037–0.568) for schwannomas and a mean of 0.017 (range: -0.429–0.258) for meningiomas, with schwannomas showing a significantly higher contrast ratio compared to meningiomas. The cutoff value for the contrast ratio obtained from the ROC curve was 0.143 (with a specificity of 90.9% and sensitivity of 88.2%), and the area under the curve (AUC) was 0.925 (95% CI: 0.852-0.998).

Discussion.

The contrast ratio can be easily measured with standard MRI, allowing for quantitative and comparative analysis of MRI images. In the differentiation of schwannomas and meningiomas, setting a cutoff value of 0.143 for the contrast ratio results in a highly useful test with high specificity and sensitivity. MRI contrast ratio measurement is useful for distinguishing schwannomas from meningiomas in intradural extramedullary spinal tumors.