Intraoperative Comparison Between Strain Elastography and Preoperative Magnetic Resonance Imaging Features in High-Grade Gliomas Using Fusion Imaging: A Pilot Study

Objective

To compare the elastographic patterns of high-grade gliomas (HGGs) solid portions and those of adjacent healthy brain parenchyma, on intraoperative ultrasound, with magnetic resonance image (MRI) characteristics.

Methods

Clinical records and images of HGGs patients, operated between June and December 2018, were retrospectively reviewed. Fusion images were used to compare preoperative gadolinium-enhanced T1-weighted MRI/fluid-attenuated inversion recovery images (Gd-T1 MRI/FLAIR) to intraoperative strain elastography (SE). FLAIR/Gd-T1 MRI images were used to define enhancement patterns (absent/whole lesion/peripheral) and lesions' characteristics (primary and secondary pattern, further subdivided in solid/necrotic/cystic/infiltrating). HGGs SE patterns were categorized as homogeneous/inhomogeneous, while lesions' primary and secondary patterns as stiff/intermediate/elastic. The SE motive of neighboring healthy brain parenchyma was defined similarly.

Results

Eighteen patients (M:F, 11:7; mean age: 53 years) harboring 14 glioblastomas (77.8%) and 4 anaplastic astrocytomas (22.2%) were compared. Glioblastomas typically enhanced peripherally and had a primary necrotic pattern (78.6% and 64.3%, respectively), while anaplastic astrocytomas did not enhance and were solid (75% both) at T1-Gd MRI and FLAIR images. At SE anaplastic astrocytomas had a homogeneous stiff primary pattern, whereas the majority of glioblastomas primary patterns were heterogeneous (85.7%) and intermediate (78.6%).

Conclusions

Three major SE patterns defined HGGs and adjacent healthy brain parenchyma. SE patterns varied according to HGG histotypes and Gd-T1 MRI/FLAIR characteristics.