Comparison of standard and delayed imaging protocols in F-18 fluorodeoxyglucose positron emission tomography and myocardial viability assessment

Introduction and Purpose: The purpose of this prospective thesis study is to compare imaging protocols with the standard protocol to determine whether delayed additional imaging in cardiac 18F-FDG-PET / CT imaging will contribute to the assessment of low myocardial uptake. Materials and Methods: Between September 2020 and March 2021, 43 out of 50 patients (37 males, 6 females, mean age 60.8 ± 9.58, mean weight 82.13 ± 17.32 kg, mean height 169.69 ± 8.50 cm) referred to our clinic for myocardial viability F-18 FDG PET / CT study have been included. 7 patients were excluded because optimal image quality could not be achieved. The times of standard and delayed additional images are respectively 65.87 ± 11.34 minutes and 109.88 ± 19.87 minutes. Before F-18 FDG injection, the mean blood glucose level of the patients was calculated as 154.79 ± 27.75 mg/dl. Semi-quantitative scoring was performed with CardIQ Physio program polar map and recorded SUVmax values according to the left ventricular 17 segment model in sagittal, axial and coronal sections from the images of the patients. Whole left ventricle and liver parenchyma SUVmax values were recorded. The data obtained were analyzed by T test in SPSS 26 and Stata / MP 16 programs. Results: Left ventricular overall SUVmax mean in standard and delayed imaging was calculated as 11.09 ± 4.90, 13.44 ± 5.93, respectively, and this increase was statistically significant (p = 0.049). Mean liver parenchyma SUVmax was calculated as 2.36 ± 0.66, 2.09 ± 0.57 in standard and delayed imaging, respectively, and this decrease was statistically significant (p = 0.044). 17 segments calculated individually when the SUVmax values and semi-quantitative scores were compared for standard and delayed imaging, there was no statistically significant difference between them. In addition, no statistically significant difference was found in groups according to the blood glucose levels of the patient according to two different cutting sections (150 and 156 mg / dl levels). In addition, when the patients were divided into two groups as diabetic and non-diabetic, no statistically significant difference was found between them. Conclusion: Although an increase in overall SUVmax in the left ventricle is observed in delayed imaging compared to standard imaging; in the quantitative and semi-quantitative assessment performed on the 17 segment model, no significant difference was found between standard and delayed images in terms of SUVmax levels and semi-quantitative scores. In the grouping made according to the presence of diabetes and blood glucose level, no significant difference was found between the delayed images and the images made with the standard protocol in SUVmax value and semi-quantitative scores. With these findings, it was concluded that cardiac viability in diabetic and non-diabetic patient groups delayed imaging in PET imaging did not contribute to the level of myocardial FDG uptake and assessment.