Individual feature maps: a patient-specific analysis tool with applications in temporal lobe epilepsy

Abstract

Purpose

MRI-based diagnosis of temporal lobe epilepsy (TLE) can be challenging when pathology is not visually evident due to low image contrast or small lesion size. Computer-assisted analyses are able to detect lesions common in a specific patient population, but most techniques do not address clinically relevant individual pathologies resulting from the heterogeneous etiology of the disease. We propose a novel method to supplement the radiological inspection of TLE patients ($n=15$) providing patient-specific quantitative assessment.

Method

Regions of interest are defined across the brain and volume, relaxometry, and diffusion features are extracted from them. Statistical comparisons between individual patients and a healthy control group ($n=17$) are performed on these features, identifying and visualizing significant differences through individual feature maps. Four maps are created per patient showing differences in intensity, asymmetry, and volume.

Results

Detailed reports were generated per patient. Abnormal hippocampal intensity and volume differences were detected in all patients diagnosed with mesial temporal sclerosis (MTS). Abnormal intensities in the temporal cortex were identified in patients with no MTS. A laterality score correctly distinguished left from right TLE in 12 out of 15 patients.

Conclusion

The proposed focus on subject-specific quantitative changes has the potential of improving the assessment of TLE patients using MRI techniques, possibly even redefining current imaging protocols for TLE.