Comparison of quantitative measurements of central nervous system tumour consistency and the associated preoperative imaging findings.

Purpose: Central nervous system (CNS) tumour consistency is one of the factors determining the difficulty of surgery for such lesions. We measured the consistency of surgically excised CNS tumour specimens using a hardness meter. The purpose of this study was to identify imaging parameters that reflect tumour consistency by comparing preoperative imaging findings with CNS tumour consistency measurements. Material and methods: Of 175 consecutive patients with CNS tumours who underwent surgery at our hospital between October 2012 and October 2018, 127 were included in this study (those whose specimens were difficult to measure were excluded). CNS tumour consistency was measured immediately after surgical excision using a hardness meter and compared with preoperative T1-weighted, T2-weighted (T2WI), fluid attenuated inversion recovery (FLAIR), diffusion-weighted imaging, gadolinium-enhanced magnetic resonance imaging, plain computed tomography (CT), and contrast-enhanced CT findings. Tumour consistency was also subjectively classified by the surgeon into soft, hard, or very hard. Results: The intracranial meningiomas were harder than the metastatic tumours and gliomas ( p = 0.03 and p = 0.03, respectively). Among the intracranial meningiomas, the tumours that exhibited high intensity on T2WI were softer than those that displayed isointensity or low intensity ( p < 0.001 and p < 0.001, respectively), and the isointense tumours were softer than the low intensity tumours ( p = 0.02). Among the metastatic tumours, the tumours that exhibited high intensity on T2WI were softer than those that displayed isointensity or low intensity ( p < 0.001 and p < 0.001, respectively). Among the intracranial meningiomas and metastatic tumours, significant correlations were detected between the T2WI findings and subjective tumour consistency according to the surgeon or quantitative tumour consistency ( p = 0.01 and p = 0.03, respectively). Conclusions: The preoperative T2WI findings of intracranial meningiomas and metastatic tumours were significantly correlated with quantitatively measured tumour consistency and subjectively evaluated tumour consistency. Therefore, we concluded that T2WI findings are useful for preoperatively predicting the consistency of such tumours.