Quantitative volumetric analysis of piriform cortex on MRI and its clinical correla- tion in drug-refractory TLE

Introduction In animal studies, an area known as the piriform cortex (PC) has been implicated to be a critical area of epileptogenesis. However, this has seen limited translation to human studies. Objective To understand the degree of damage to PC in patients with temporal lobe epilepsy (TLE) as well as to correlate clinical characteristics of TLE with PC volumetry. Methods Manual segmentation of the PC on structural MR images of 60 consecutive adults with drug- refractory unilateral TLE and 20 age matched control subjects was performed. Univariate and multivari- ate regression models were employed to examine the relationship of PC and hippocampal volumes with clinical variables collected. Results In controls, consistent asymmetry between the left and right PC was found. The right PC was consistently larger than the left across all study groups. Notably, the inter-rater and intra-rater variability were in good agreement. This study found that both the ipsilateral (r=-0.291, p=0.012) and contralateral (r=-0.338, p= 0.008) PC volumes have a negative correlation with the duration of epilepsy. Therefore, evidencing the damage of PC in mesial TLE. The temporal atrophy of the PC correlated with temporal atrophy of the hippocampus. This study could not strongly establish the correlation between any other clinical variable studied. Conclusion Further longitudinal studies are required to confirm the findings of this study to enable the PC to be considered in treatment strategies for patients with drug-refractory TLE. siqbal2482@gmail.com