Predicting meningioma consistency and brain-meningioma interface with intraoperative strain ultrasound elastography: a novel application to guide surgical strategy

Abstract

OBJECTIVEProviding new tools to improve surgical planning is considered a main goal in meningioma treatment. In this context, two factors are crucial in determining operating strategy: meningioma-brain interface and meningioma consistency. The use of intraoperative ultrasound (ioUS) elastosonography, a real-time imaging technique, has been introduced in general surgery to evaluate similar features in other pathological settings such as thyroid and prostate cancer. The aim of the present study was to evaluate ioUS elastosonography in the intraoperative prediction of key intracranial meningioma features and to evaluate its application in guiding surgical strategy.METHODSAn institutional series of 36 meningiomas studied with ioUS elastosonography is reported. Elastographic data, intraoperative surgical findings, and corresponding preoperative MRI features were classified, applying a score from 0 to 2 to both meningioma consistency and meningioma-brain interface. Statistical analysis was performed to determine the degree of agreement between meningioma elastosonographic features and surgical findings, and whether intraoperative elastosonography was a better predictor than preoperative MRI in assessing meningioma consistency and slip-brain interface, using intraoperative findings as the gold standard.RESULTSA significantly high degree of reliability and agreement between ioUS elastographic scores and surgical finding scores was reported (intraclass correlation coefficient = 0.848, F = 12.147, p < 0.001). When analyzing both consistency and brain-tumor interface, ioUS elastography proved to have a rather elevated sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and positive (LR+) and negative likelihood ratio (LR−). This consideration was true especially for meningiomas with a hard consistency (sensitivity = 0.92, specificity = 0.96, PPV = 0.92, NPV = 0.96, LR+ = 22.00, LR− = 0.09) and for those presenting with an adherent slip-brain interface (sensitivity = 0.76, specificity = 0.95, PPV = 0.93, NPV = 0.82, LR+ = 14.3, LR− = 0.25). Furthermore, predictions derived from ioUS elastography were found to be more accurate than MRI-derived predictions, as demonstrated by McNemar’s test results in both consistency (p < 0.001) and interface (p < 0.001).CONCLUSIONSWhile external validation of the data is needed to transform ioUS elastography into a fully deployable clinical tool, this experience confirmed that it may be integrated into meningioma surgical planning, especially because of its rapidity and cost-effectiveness.

Multiparametric Intraoperative Ultrasound in Oncological Neurosurgery: A Pictorial Essay

“…Elastosonography instead, by directly calculating the lesions’ Young modulus, provides real-time, intuitive imaging of meningiomas’ stiffness and relation to surrounding structures. From our experience, this feature plays a pivotal role in the planning of resection strategy, to the point of influencing the choice of a particular instrument or approach ( Figure 7 ; Prada et al, 2015 ; della Pepa et al, 2020 ).…”

“…This technique exploits a US stimulus to induce tissue displacement, thus providing a quantitative representation of the stiffness. In the current practice, elastosonography seems useful mainly in gliomas and meningiomas characterization ( Figure 4 ; Prada et al, 2015 , 2016b , 2019 ; della Pepa et al, 2020 ; Cepeda et al, 2021a ; Chan et al, 2021 ; Menna et al, 2021 ; Yin et al, 2021 ).…”

The Neurosurgeon’s Armamentarium for Gliomas: An Update on Intraoperative Technologies to Improve Extent of Resection

“…IOUS has been shown to have high sensitivity and specificity both adult and pediatric brain tumors [92]. Ultrasound is a highly multi-modal technology, and may be used to determine tissue composition with elastosonography [81], detect flow patterns in tumor vessels with micro vessel power doppler [93] and may be fused with MR imaging to reduce radiation with fluoroscopy [94].…”

Editorial comment on “A new method for quantification and 3D visualization of brain tumor adhesion using slip interface imaging in patients with meningiomas”

“…This weakness opened the door to what has been called "mechanoimaging": identification of tumour features using biomechanical information. In this sense, Taoka et al [6] tested brain surface motion imaging, based on T2wi during different phases of the cardiac cycle; Zying et al [7] and Hughes et al [8] evaluated the utility of slip interface imaging (SII), based on MR elastography (MRE) during the application of an external dynamic vibration; or very recently, Della Pepa et al [9] have tried intraoperative ultrasound elastosonography.…”