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ObjectiveTo examine the effect of multimodal intraoperative neuromonitoring on the long-term outcome of motor function after microsurgical resection for spinal cord tumors.Materials and MethodsConsecutive fourteen patients with spinal tumors who were surgically treated at the University of Fukui Hospital between 2009 and 2020 [M:F = 10:4, ages ranging from 22 to 83 years (mean ± SD = 58 ± 21 years)] were included in this study. There were eight intra-axial tumors and six extra-axial tumors. There were four patients with hypertension, two patients with diabetes mellitus, and four patients with hyperlipidemia. Three patients were under antithrombotic medication, two were under steroid medication, four were current smokers, and four were current drinkers. Manual muscle test (MMT) of the upper and lower extremities of the patients was examined before surgery, 2 weeks after surgery, and at the final follow-up. The mean follow-up period was 38 ± 37 months. McCormick scores were examined before surgery and at the final follow-up. Microsurgical resection of the tumor was underwent through the posterior approach under transcranial motor-evoked potential (TcMEP) monitoring. The MEP of 46 extremities was recorded during the surgery. Gross total resection was achieved in 13 of 14 surgeries. Spinal cord-evoked potential (Sp-SCEP) monitoring was performed in eight of 14 patients.ResultsThe length of peritumoral edema was significantly longer in patients with deterioration of McCormick scores than in patients with preservation of McCormick scores (p = 0.0274). Sp-SCEP could not predict the deterioration. The ratio of MEP at the beginning of the surgery to that at the end of the surgery was the only significant negative factor that predicts deterioration of motor function of the extremity at the final follow-up (p = 0.0374, odds ratio [OR] 1.02E-05, 95% CI 9.13E+01–7.15E+18). A receiver operating characteristic (ROC) analysis revealed that the cutoff value of the ratio of MEP to predict the deterioration at the final follow-up was 0.23 (specificity 100%, specificity 88%, positive predictive value 100%, and negative predictive value 88%) to predict deterioration at the final follow-up.ConclusionsRatio MEP was the most significant negative factor to predict the deterioration of motor weakness at spinal tumor surgery. The setting of the cutoff value should be more strict as compared to the brain surgery and might be different depending on the institutions.

Background In glioma, decision of infiltrating margin in extensive FLAIR hyperintensity area around enhanced area and only FLAIR hyperintensity without enhanced is difficult. For deciding this margin, there are some useful reports using perfusion imaging, diffusion-weighted imaging and PET. Recently, there are some reports that amide proton transfer (APT) imaging is useful for assessment for tumor invasion. In this study, we assessed FLAIR hyperintensity area in gliomas using APT imaging and discussed about pattern of APT signal intensity (SI). Methods For patients with glioblastoma (GBM) and oligodendroglioma (OL: IDH-mutant and 1p/19q-codeleted), APT imaging was performed. Gadolinium T1WI, FLAIR and apparent diffusion coefficient (ADC) were performed for tumor invasion and edema. Areas of these sequences were compared with APT hyperintensity and APT and ADC were determined the quantity by SI. Results 37 sections from 10 GBM and 5 OL patients were assessed. Areas of differences between FLAIR and APT hyperintensity was significantly different between GBM and OL (p = 0.0142). SIs of the hyperintensity area between GBM and OL were different on ADC and APT SIs (ADC: p = 0.0267 / APT: p = 0.055). On GBM, hyperintensity area of APT imaging showed a correlation with hyperintensity area of FLAIR (R2 = 0.600, p < 0.0001). On OL, hyperintensity area of APT imaging showed a strong correlation with hyperintensity area of FLAIR (R2 = 0.806, p < 0.0001), and ADC SI showed correlation with APT SI (R2 = 0.675, p = 0.0019). Conclusions FLAIR hyperintensity area of GBM and OL, APT imaging showed different distribution. In FLAIR hyperintensity area of GBM with various phenomenon, APT imaging may indicate increasing area of tumor cell and reactive cells. Furthermore, mismatch between FLAIR and APT hyperintensity area may be useful for differentiation for glioma subtypes.

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BACKGROUND: Infiltrative gliomas show cerebral edema and tumor infiltration as areas of hyperintensity in FLAIR image. Amide proton transfer (APT) and cerebral blood flow (CBF) are useful for evaluating the tumor invasion. In this study, arterial spin-labeling (ASL)-CBF and APT were compared to determine which method was superior for predicting tumor infiltration in gliomas, pathologically. METHODS: Fifteen specimens from 5 glioma patients with confirmed selective sampling were obtained. Based on APT signal intensity (SI), regions of interests (ROIs) were selected for biopsy. Same regions of these ROIs were marked on the same slice of ASL imaging. Samples were pathologically assessed for cell density and vessel density. APT SI and ASL-CBF were analyzed for each specimen. RESULTS: APT signal intensity (SI) showed a strong correlation with cell density (R = 0.887, P < 0.0001). ASL-CBF showed no correlation with cell density (R = 0.240; P = 0.3836) but a correlation with vessel density (R = 0.697; P = 0.0038). In linear regression analysis, APT SI showed a positive relationship with cell density (R2 = 0.787, P < 0.0001, linear regression; y = 30.70 + 6.24E-3*x). CONCLUSIONS: APT imaging was superior in predicting cellular proliferation than ASL-CBF and a powerful predictor of cell density. APT imaging allowed revelation of novel clues reflecting tumor proliferation in brain tumor; to date, this is the first known report to assess cell density among various brain tumors and conditions after treatment.