Early 99mTc-DPD imaging at 1 hour post-injection provided diagnostic performance equivalent to conventional late imaging at 2.5-3 hours for detecting cardiac ATTR amyloidosis, despite a significantly higher median visual Perugini score (0.5 vs. 0, p<0.001).
Observational (n=50)
Blinded readers
Yes
Does early imaging (1 hour post-injection) using 99mTc-DPD scintigraphy provide comparable diagnostic accuracy to late imaging (2.5-3 hours) for detecting cardiac ATTR amyloidosis?
Early 1-hour 99mTc-DPD imaging provides equivalent diagnostic accuracy to standard 3-hour imaging for ATTR-CM, potentially improving workflow and patient comfort, though visual scoring thresholds may need adjustment due to higher blood pool activity.
Absolute Event Rate: 0.5% vs 0%
p-value: p=<0.001
Abstract Background Cardiac transthyretin amyloidosis (ATTR-CM) is a progressive myocardial disease ultimately leading to heart failure. Standard diagnostic workup includes 99m Tc-DPD scintigraphy performed after 2.5–3 h. The purpose of this study is to compare early (1 h after injection) to late imaging of 99m Tc-DPD scintigraphy and SPECT for the detection of ATTR-CM. Early imaging could improve patient comfort and examination efficiency. Results 50 patients undergoing 99m Tc-DPD scintigraphy and SPECT for suspected ATTR-CM were included. Imaging was performed at both 1 h and 2.5–3 h post-injection. Tracer uptake was assessed visually (Perugini score), semi-quantitatively (e.g., heart-to-mediastinum ratio, HMR), and quantitatively (e.g., maximum standardized uptake value, SUV max ). ATTR-CM was diagnosed in 28% of patients. Median visual Perugini score was significantly higher for early imaging (0.5 vs. 0, p < 0.001). Findings were validated using an external validation cohort. Intraclass correlation coefficients between early and late imaging were very good. Visual evaluation of early imaging demonstrated comparable sensitivity, specificity, and overall diagnostic accuracy to late imaging. HMR and SUV max from early imaging showed higher diagnostic accuracy. No false-negative results were observed. Visual evaluation using the Perugini score was slightly less consistent between readers in early compared to late imaging, with lower inter-observer agreement at 1 h. Conclusions Early 99m Tc-DPD imaging provides diagnostic performance equivalent to conventional late imaging while substantially enhancing patient comfort and workflow efficiency. Adoption of early imaging protocols, complemented by quantitative and semi-quantitative analysis, may streamline ATTR-CM diagnostics, enabling timely diagnosis and treatment.
Settelmeier et al. (Fri,) conducted a observational in Cardiac ATTR amyloidosis (n=50). Early (1 h) 99mTc-DPD scintigraphy vs. Late (2.5-3 h) 99mTc-DPD scintigraphy was evaluated on Median visual Perugini score (p=<0.001). Early 99mTc-DPD imaging at 1 hour post-injection provided diagnostic performance equivalent to conventional late imaging at 2.5-3 hours for detecting cardiac ATTR amyloidosis, despite a significantly higher median visual Perugini score (0.5 vs. 0, p<0.001).