Assessment Relation of Myocardial Detector Counts and Administered Activity of 99mTc-SestaMIBI in MPI: The Effects of Body Weight, BMI, and Gender.

Abstract

In myocardial perfusion imaging, reducing the number of photons in images of obese patients causes poor image quality. To solve this problem, we need to inject the tracer according to the patients' weight. Therefore, this study aimed to investigate the relationship between myocardial photon counts with patients' weight, BMI, and gender. A total of 129 patients underwent myocardial perfusion imaging in a twoday stress-first protocol, but only rest images were included in this study. Multiplication factor <img src="/images/article-115470.png" /> was used to determine the amount of radiopharmaceutical activity injected into the patients. For evaluating the effect of gender, the photon counts of 22 female patients were also assessed when the breast tissue was pulled upward (Breast Up). The total myocardial detector counts in the raw images were calculated from the summation of 32 projections. A multiple linear regression test was used to simultaneously examine the effects of weight, BMI, and gender on photon counts. There was no significant relationship between photon counts and patients' weight (p=0.129) and BMI (0.406), but gender had significant effects on photon counts, and myocardial detector counts were found to be higher in males (p=0.00). There was a statistically significant difference between the images of Breast Up and Non-Breast Up, and myocardial detector counts were higher in the Breast Up imaging method (p=0.00). Using the bodyweight formula, the image quality was comparable in obese and lean patients, but myocardial detector counts were lower in females, and this formula needs to be adjusted according to the patient's gender.