Abstracts

Rationale: NeuroQuant (NQ) is an FDA approved software that performs automatic MRI quantitative volumetric analysis. There is a paucity of literature investigating its clinical utility in a real patient population. This study aims to compare the accuracy of NQ relative to neuroradiologists in detecting MRI signs of hippocampal sclerosis (HS). Methods: We included 144 adult patients with no prior brain surgery, who underwent a temporal lobe resection for epilepsy at Cleveland Clinic from 2010 to 2017. The “gold standard” for the presence of HS was defined by pathology (as confirmed by expert neuropathologist review). Nonspecific findings on pathology were classified as no HS. MRI was acquired on a 3T scanner. An epilepsy neuroradiologist reviewed the pre-operative MRI and classified patients as having HS or not. Questionable signs of HS were classified as no-HS. After de-identifying the MRIs, we used NQ to quantify the volume of the eventually resected hippocampus. The results were given in percentile (based on age- and gender-matched normative cohort controls). Percentiles below 5 were considered abnormal. We used a McNemar’s paired proportions test to compare the specificity and sensitivity of identifying HS between NQ and neuroradiologist reports. Results: There were no differences between the HS group versus no-HS defined by pathology, but for age (Table 1). Distribution of hippocampus volumes (in percentile) is described in table 1. Sensitivity, specificity, positive predictive values, and negative predictive values are presented in Table 2. We found that NQ has the same specificity (p=1) but lower sensitivity when compared to neuroradiologists (69% vs 93%; p<0.001). Conclusions: The lower sensitivity of NQ is most likely due to its inability to evaluate the presence of other imaging criteria of HS such as increased T2 signal and loss of hippocampal structural architecture. NeuroQuant only assesses changes in hippocampal volume loss. Given its high specificity, NQ is a valuable tool, especially for centers with limited resources (e.g., those that lack a radiologist with epilepsy-specific expertise). For those cases with positive signs of HS on NQ, patients should be referred for pre-surgical evaluation; whereas negative results, potentially provide a justification for case referral for further evaluation by a trained neuroradiologist in epilepsy. Funding: NIH Grant R01NS097719