Reliability of the 123 I- m IBG heart/mediastinum ratio: Results of a multicenter test –retest reproducibility study

This study assessed the test–retest reproducibility of the H/M ratio in such patients. 47 subjects with class II-III systolic heart failure and LVEF ≤ 35% were tested at two time intervals separated by 5 to 14 days. Subjects were imaged twice on the same camera using the same radi onuclide dose. Images were sent to a core analysis lab, where three nuclear technologists independently determined the H/M ratios. The primary endpoint was test–retest H/M ratio reproducibility calculated as the absolute difference in mean value determined by the three readers. Mean subject age wa s 65 ± 12 years, 85% were male, and mean BMI was 29 ± 6 kg/m2. Mean injected activity was 10.18  ± 0.43 mCi for first dose and 10.09 ± 0.52 mCi for the second dose. The mean and SD values for first and repeat studies were almost identical: the 95% confidence interval of the mean test–retest difference was 0.055 to 0.076. Bland–Altman plots showed no systematic effect of the H/M rat io on the magnitude of the difference between replicate measurements. Inter-reader measurements were nearly identical. There were no serious adverse events despite exposure to123I-mIBG on 2 occasions in a short time period. The Heart-to-Mediastinum ratio of123I-mIBG is a consistent and highly reproducible measurement in stable Class II to III heart failure patients.
Source: Journal of Nuclear Cardiology - Category: Nuclear Medicine Source Type: research