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

To distinguish neurodegenerative diseases using ¹²³I-metaiodobenzylguanidine (MIBG). This study proposes a method to evaluate myocardial standardized uptake value (SUV) and assess its accuracy.

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.

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 SUV_max (MaxSUV_max) and (2) average SUV_max (AveSUV_max) 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 MaxSUV_max and AveSUV_max were 8.27 and 7.58, respectively.

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.