Evaluation of the difference-correction effect of the gamma camera systems used by easy Z-score Imaging System (eZIS) analysis

Objective: We examined the difference of the effect by data to revise a gamma camera difference. The difference-correction method of the camera is incorporated in eZIS analysis. Methods: We acquired single photon emission computed tomography (SPECT) data from the three-dimensional (3D) Hoffman brain phantom (Hoffman), the three-dimensional brain phantom (3D-Brain), Pool phantom (pool) and from normal subjects (Normal-SPECT) to investigate compensating for a difference in gamma camera systems. We compared SPECT counts of standard camera with the SPECT counts that revised the difference of the gamma camera system (camera). Furthermore, we compared the "Z-score map (Z-score)". To verify the effect of the compensation, we examined digitally simulated data designed to represent a patient with Alzheimer\u27s dementia. We carried out both eZIS analysis and "Specific Volume of interest Analysis (SVA)". Results: There was no great difference between the correction effect using Hoffman phantom data and that using 3D-Brain phantom data. Furthermore, a good compensation effect was obtained only over a limited area. The compensation based on the pool was found to be less satisfactory than any of the other compensations according to all results of the measurements examined in the study. The compensation based on the Normal-SPECT data resulted in a Z-score map (Z-score) for the result that approximated that from the standard camera. Therefore, we concluded that the effect of the compensation based on Normal-SPECT data was the best of the four methods tested. Conclusions: Based on eZIS analysis, the compensation using the pool data was inferior to the compensations using the other methods tested. Based on the results of the SAV analysis, the effect of the compensation using the Hoffman data was better than the effect of the compensation using the 3D-Brain data. By all end-point measures, the compensation based on the Normal-SPECT data was more accurate than the compensation based on any of the other three phantoms. © 2014 The Author(s).発行後1年より全文公

Novel method for quantitative evaluation of cardiac amyloidosis using 201TlCl and 99mTc-PYP SPECT

Objective The degree of myocardial technetium- 99m- pyrophosphate ( 99mTc-PYP) accumulation in cardiac amyloidosis is conventionally evaluated by the PYP score. This method involves qualitative visual evaluation on twodimensional images. Here, we performed three-dimensional quantitative analysis using software developed in our laboratory. Methods We performed dual myocardial imaging using thallium- 201-chloride ( 201Tl-Cl) and 99mTc-PYP in cases of suspected cardiac amyloidosis and calculated the PYP accumulation rates of all myocardial pixels showing 99mTc- PYP accumulation. We defined this procedure as quantitative evaluation of the degree of 99mTc-PYP accumulation in the myocardium. Patients were divided into two groups with and without a diagnosis of cardiac amyloidosis, and we examined the PYP accumulation rates in both groups. In addition, we examined the PYP scores of the two groups by conventional qualitative evaluation. Results The PYP scores of the cardiac amyloidosis group were significantly higher than those of the other group. The PYP accumulation rates of the cardiac amyloidosis group were significantly higher than those of the other group. There were significant differences in the PYP accumulation rate and PYP score between the two groups. There was considered to be a threshold between the two groups in the case of the PYP accumulation rate. Conclusions When the threshold of the PYP score was defined as 3+ and that of the PYP accumulation rate as 41.5 %, the sensitivity of the PYP score and PYP accumulation rate was 84.6 %. However, the specificity of the PYP accumulation rate was higher than that of the PYP score. Quantitative evaluation by the PYP accumulation rate of the degree of 99mTc-PYP accumulation in the myocardium may be useful in the diagnosis of cardiac amyloidosis. © The Japanese Society of Nuclear Medicine 2012