The Bayesian Penalized Likelihood (BPL) PET reconstruction technique improve detection of epileptogenic focus by hybrid PET/MRI, a primary study

Introduction: To explore the value of BPL PET reconstruction technique for detection of epileptogenic focus with 18F-FDG hybrid PET/MRI

Methods: Five patients who underwent brain ¹⁸F-FDG PET/MRI in our center for finding the epileptogenic focus were included in these study. These five patients were all diagnosed with epilepsy by epileptic seizure. The PET was scanned by hybrid PET/MRI after injection of 18F-FDG almost 40 min and the scanning time was 15 min, during which the multiple MRI sequences were scanned, including the 3D T1 MRI. Then the PET list-mode data were reconstructed by the traditional ordered subsets expectation maximization (OSEM) and the BPL technique (β=200) respectively. We used the software (named by AICaculation 1.0) developed by ourselves based on the Matlab 2020b and SPM 12 to obtain the SUVs and the asymmetry index (AI) for 128 brain regions. The two senior doctors who underwent diagnosis at least 10 years found out the suspicious epileptogenic focus according to the PET and MRI results. Total 34 brain regions were found out. At last, we compared the SUVs and AI for the 34 brain regions between the traditional OSEM reconstruction group and the BPL reconstruction group by paired t test and p<0.05 was considered the difference was significant.

Results: The SUVmax, SUVmean in the left brain regions and the SUVmax in the right brain regions showed no significant difference between the two reconstruction methods (p>0.1). The SUVmean in the right brain regions showed significant difference (p<0.01), while the difference was small (6.48±1.46 vs 6.60 ±1.54). For the AI in the suspicious brain regions, the values were 15.59±8.71 vs 17.69±10.17 for the OSEM reconstruction vs BPL reconstruction. The AI increased a little for BPL reconstruction, which was helpful for detection of epileptogenic focus, while the increasing was insignificant (p=0.067).

Conclusions: The primary study suggested the BPL PET reconstruction could increase the AI values in the suspicious epileptogenic focus, which was helpful for detection of epileptogenic focus with 18F-FDG hybrid PET/MRI.

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