Optimization of image reconstruction method of cerebral blood flow perfusion imaging with digital CZT SPECT.

Yaqian Zhou,Xuan Wang,Wei Zheng,Ning Li,Shen Wang,Peng Wang

doi:10.1097/mnm.0000000000001540

Abstract

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. 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. 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. 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.

Highlights

As a common clinical neurosurgical disease, ischemic cerebrovascular disease has high disability and mortality rates worldwide
When compared to single-photon emission computed tomography (SPECT) equipped with a traditional sodium iodide detector (NaI SPECT), SPECT equipped with a CZT semiconductor detector (CZT SPECT) provides better image quality, and the spatial resolution, energy resolution, and contrast of CZT SPECT images have significantly improved [4,5,6]
With an increase in the fc value, the uniformity and noise of the image increased (Fig. 2A), the contrast-to-noise ratio (CNR) of the image decreased (Fig. 4A), and the contrast increased (Fig. 3A), which could distinguish smaller cold spheres, while the contrast and CNR decreased with decreasing diameter of the cold ball

Summary

Introduction

As a common clinical neurosurgical disease, ischemic cerebrovascular disease has high disability and mortality rates worldwide. Cerebral blood perfusion imaging can be used to assess the local cerebral blood flow and cerebrovascular reserve at rest, and it has unique advantages in lesion guidance; prognostic evaluation of many diseases such as cerebral infarction, transient ischemic attack (TIA), epilepsy, and other ischemic lesions; and normal brain function research [1,2,3]. With the development of imaging technology, especially functional imaging, single-photon emission computed tomography (SPECT) has played an increasingly important role in the localisation and diagnosis of ischemic cerebrovascular diseases. The development of digital universal tellurium-zinc-cadmium (CZT) cameras has promoted new advances in SPECT imaging technology. When compared to SPECT equipped with a traditional sodium iodide detector (NaI SPECT), SPECT equipped with a CZT semiconductor detector (CZT SPECT) provides better image quality, and the spatial resolution, energy resolution, and contrast of CZT SPECT images have significantly improved [4,5,6]

Methods

Results

Discussion

Conclusion