Investigation of the optimal cut-off frequency of pre-processing filter in cerebral perfusion SPECT images. Comparison between physical and visual evaluation method

The purpose of this study is to compare physical evaluation with visual evaluation in the determination of optimum cut-off frequency of the pre-processing filter for cerebral perfusion single photon emission computed tomography (SPECT) images. The normalized mean squared error (NMSE) study was used for physical evaluation. The receiver operating characteristic (ROC) study was used for visual evaluation. In the phantom study, the optimal cut-off frequencies were 0.698 cycle/cm by calculating the NMSE. In the patient study, the ROC results indicated statistically significant rise in detection performance with 0.698 cycle/cm (average Az 0.718) compared with 0.581 cycle/cm (average Az 0.587) and 1.163 cycle/cm (average Az 0.614). The result of NMSE and ROC was in agreement. Therefore, it was suggested that adjustment is in physical and visual evaluation. (author)