Three-dimensional Quantitative Evaluation Method in 123I-MIBG Myocardial SPECT-CT

Purpose: To distinguish neurodegenerative diseases using 123I-metaiodobenzylguanidine (MIBG). This study proposes a method to evaluate myocardial standardized uptake value (SUV) and assess its accuracy. Methods: We created a 17-segment polar map of the myocardial region from single-photon emission computed tomography-computed tomography (SPECT-CT) images using a cardioliver phantom simulating the standard uptake of MIBG. We clarified the optimal reconstruction conditions with good repeatability and accuracy of quantitative values and compared them with the H/M ratio. Myocardial SUVs were evaluated from eight normal cases using our method established from the phantom experiment and compared with the H/M ratio. Results: The optimal numbers of iterations and subsets in OSEM reconstruction were both 10. The optimal full width at half maximum (FWHM) value of the Gaussian filter was 4 pixels. The RCs and %CV of (1) maximum SUVmax (MaxSUVmax) and (2) average SUVmax (AveSUVmax) were (1) 36.5% and 4.99%, and (2) 33.6% and 4.84%, respectively. The RC and %CV of the H/M ratio was 15.0% and 1.50%, respectively. In clinical cases, average MaxSUVmax and AveSUVmax were 8.27 and 7.58, respectively. Conclusion: Myocardial SUV can provide quantitative values slightly closer to theoretical values than the H/M ratios. Besides, using the optimal reconstruction parameters makes it feasible to quantitatively assess myocardial uptake with good repeatability.