Joint reconstruction of Ictal/inter-ictal SPECT data for improved epileptic foci localization.PURPOSE
 To improve the performance for localizing epileptic foci, we have developed a joint ictal/inter-ictal SPECT reconstruction method in which ictal and inter-ictal SPECT projections are simultaneously reconstructed to obtain the differential image.


 We have developed a SPECT reconstruction method that jointly reconstructs ictal and inter-ictal SPECT projection data.  Two low-noise SPECT projection datasets were acquired using 99m Tc and a Hoffman head phantom at two different positions and orientations.  Compared with the conventional subtraction approach, the SD reduction of lesion contrast at the 10th iteration using our joint method ranges from 54.7% to 68.2% (P < 0.0005), and 33.8% to 47.9% (P < 0.05) for 2 and 4 million total inter-ictal counts, respectively.  In the patient study, our joint method increases the area under LROC from 0.24 to 0.34 and from 0.15 to 0.20 for the first and second reader, respectively. 
SPECT