Analysis of Brain SPECT Images Coregistered with MRI in Patients with Epilepsy: Comparison of Three Methods

SISCOM and STATISCOM were clinically proved to be effective for ictal/inter-ictal single-photon emission computed tomography (SPECT) analysis coregistered with magnetic resonance imaging (MRI) for seizure localization. Recently, a software package also became available for this analysis. This study aimed to investigate and compare the performance of these analysis methods for seizure localization.

A total of 378 patients who underwent ^99m Tc-ethyl cysteinate dimer (ECD) SPECT scans were retrospectively reviewed and 28 remained after applying exclusion criteria. Their SPECT and MRI images were analyzed with SISCOM (with z-score of 1.5 and 2), STATISCOM, and MIMneuro, resulting in a total of 112 image data sets. Two experienced radiologists participated in the blind review process using a custom tool and they can mark up to two hyper- and/or hypoperfusion regions. Their review results were analyzed using the Jackknife Free Response Receiver-Operating Characteristics (JAFROC) test and the JAFROC figure-of-merit (FoM) was reported for each method. The interobserver agreement was also assessed using Cohen's kappa test.

Based on the readers' two choices, averaged FoM was 85.7%, 83.9%, 66.1%, and 51.8% for STATISCOM, MIMneuro, SISCOM (z-score = 2), and SISCOM (z-score = 1.5), respectively. The average confidence rating was 2.5, 2.3, 1.6, and 1.1 for STATISCOM, MIMneuro, SISCOM (z-score = 2), and SISCOM (z-score = 1.5), respectively. For interobserver agreement, kappa was .742 for STATISCOM, .816 for MIMneuro, .517 for SISCOM (z-score = 2), and .441 for SISCOM (z-score = 1.5; all P < .001).

Our study demonstrated that STATISCOM showed the best performance for seizure localization, which was closely followed by MIMneuro. In addition, MIMneuro was not inferior to SISCOM with either z-score.