Clinical Evaluation of a Quantitative Imaging Biomarker Supporting Radiological Assessment of Hippocampal Sclerosis

Abstract

Objective: To evaluate the influence of quantitative reports (QReports) on the radiological assessment of hippocampal sclerosis (HS) from MRI of patients with epilepsy in a setting mimicking clinical reality. Methods: The study included 40 patients with epilepsy, among them 20 with structural abnormalities in the mesial temporal lobe (13 with HS). Six raters blinded to the diagnosis assessed the 3T MRI in two rounds, first using MRI only and later with both MRI and the QReport. Results were evaluated using inter-rater agreement (Fleiss’ kappa $$k$$ k ) and comparison with a consensus of two radiological experts derived from clinical and imaging data, including 7T MRI. Results: For the primary outcome, diagnosis of HS, the mean accuracy of the raters improved from 77.5% with MRI only to 86.3% with the additional QReport (effect size $$d=1.43$$ d = 1.43 ). Inter-rater agreement increased from $$k=0.56$$ k = 0.56 to $$k=0.72$$ k = 0.72 . Five of the six raters reached higher accuracies, and all reported higher confidence when using the QReports. Conclusion: In this pre-use clinical evaluation study, we demonstrated clinical feasibility and usefulness as well as the potential impact of a previously suggested imaging biomarker for radiological assessment of HS.

Cortical thickness and grey-matter volume anomaly detection in individual MRI scans: Comparison of two methods

“…Recently, first clinical evaluation studies have become available for non-commercial, research-level and open-source tools for brain morphometry. In small case-control studies focusing on hippocampal sclerosis in temporal lobe epilepsy, Goodkin et al (2021) and Rebsamen et al (2023c) have compared expert ratings without and with availability of quantitative reports (QReports). Both found that with QReports available the accuracy and rater confidence for presence of hippocampal sclerosis increased, whereas disagreement among experts reduced.…”

“…In this paper we have compared identical metrics derived from two brain morphometry software tools, i.e. DL+DiReCT (Rebsamen et al, 2020(Rebsamen et al, , 2023 and FreeSurfer (Dale et al, 1999;Fischl et al, 1999aFischl et al, , 1999bFischl & Dale, 2000), regarding their use in the context of ScanOMetrics, an open-source pipeline for normative modeling and detection of statistical anomalies (Rummel et al, 2017. ScanOMetrics processing is supposed to detect abnormal regions in individual MRI scans, which may support neuroradiological assessment of the cases with respect to many clinical questions.…”

“…This might indicate a higher sensitivity of DL+DiReCT to atrophy progression in the individual, supporting our hypothesis (3). Since sensitivity to atrophy and reproducibility of patterns has mainly been compared for CTh and not for GMV so far (Rebsamen et al, 2020(Rebsamen et al, , 2023Rusak et al, 2022), this hypothesis requires additional investigation in subsequent work.…”