Optimization of image reconstruction method of cerebral blood flow perfusion imaging with digital CZT SPECT
Yaqian Zhou1, Shen Wang, Peng Wang
1Department of Nuclear Medicine, Tianjin Medical University General Hospital, Tianjin, China.
Purpose:
The purpose of this study is to evaluate the effects of filtered back projection (FBP), ordered subset expectation maximisation (OSEM), and different filters on cadmium zinc telluride single-photon emission computed tomography [CZT single-photon emission computed tomography (SPECT)] cerebral blood perfusion image quality to optimise the image reconstruction method.
Methods:
Under routine clinical conditions, tomographic imaging was performed on the phantom and patients. Image processing included image reconstruction using FBP and OSEM, and the filtering method used Butterworth (Bw) and Gaussian (Gs) filters. Visual and semi-quantitative parameters [integral uniformity, root mean square (RMS) noise and contrast and contrast-to-noise ratio (CNR)] were used to evaluate image quality to optimise image reconstruction parameters. One-way and two-way analysis of variance were used to process phantom and clinical data.
Results:
In the tomographic images of the phantom, the semi-quantitative analysis showed that the integral uniformity of FBP+Bw was better than that of OSEM+Bw and OSEM+Gs (P < 0.05), and that the RMS noise of FBP+Bw was lower than that of OSEM+Bw and OSEM+Gs (P < 0.001). The contrast of FBP+Bw and OSEM+Bw in the cold area diameter ≥2 cm group was higher than that of OSEM+Gs (P < 0.001), whereas the CNR of FBP+Bw was higher than that of OSEM+Bw and OSEM+Gs (P < 0.001); the contrast of OSEM+Bw cold area diameter <2 cm was higher than that of FBP+Bw (P < 0.01). The semi-quantitative analysis results of the clinical images were consistent with the phantom's.
Conclusion:
In CZT SPECT cerebral blood flow perfusion imaging, it is suggested that the image postprocessing method of FBP+Bw (fc = 0.40; n = 10) should be used routinely in clinical application, and if there are uncertain small lesions in the processed image, it is suggested to use the reconstruction method of OSEM+Bw (EM-equivalent iterations = 60; fc = 0.45; n = 10) instead.
