TY - JOUR T1 - Three-hour delayed imaging improves assessment of coronary <sup>18</sup>F-sodium fluoride PET JF - Journal of Nuclear Medicine JO - J Nucl Med DO - 10.2967/jnumed.118.217885 SP - jnumed.118.217885 AU - Jacek Kwiecinski AU - Daniel S. Berman AU - Sang-Eun Lee AU - Damini Dey AU - Sebastien Cadet AU - Martin L Lassen AU - Guido Germano AU - Maurits A Jansen AU - Marc R Dweck AU - David E Newby AU - Hyuk-Jae Chang AU - Mijin Yun AU - Piotr Slomka Y1 - 2018/09/01 UR - http://jnm.snmjournals.org/content/early/2018/09/13/jnumed.118.217885.abstract N2 - Coronary 18F-sodium fluoride (18F-NaF) PET imaging identifies ruptured plaques in patients with recent myocardial infarction and localizes to atherosclerotic lesions with active calcification. Most studies to date performed the PET acquisition 1-hour (1h) post-injection. Although qualitative and semi-quantitative analysis is feasible with 1h images, often residual blood pool activity makes it difficult to discriminate plaques with 18F-NaF uptake from noise. We aimed to assess whether delayed 3-hour (3h) post-injection PET scan improves image quality and uptake measurements. Methods: Twenty patients (67±7years old, 55% male) with stable coronary artery disease underwent coronary CT angiography and PET/CT both 1 h and 3 h after the injection of 266.2±13.3 MBq of 18F-NaF. We compared the visual pattern of coronary uptake, maximal background (blood pool) activity, noise, standard uptake values (SUVmax), corrected SUV (cSUVmax) and target to background (TBR) measurements in lesions defined by CTA on 1h vs 3h post injection 18F-NaF PET. Results: On 1h PET 26 CTA lesions with 18F-NaF PET uptake were identified in 12 (60%) patients. On 3h PET we detected 18F-NaF PET uptake in 7 lesions which were not identified on the 1h PET. The median cSUVmax and TBR values of these lesions were 0.48 [interquartile range (IQR) 0.44-0.51] and 1.45 [IQR, 1.39-1.52] compared to -0.01 [IQR, -0.03-0.001] and 0.95 [IQR, 0.90-0.98] on 1h PET, both p&lt;0.001. Across the entire cohort 3h PET SUVmax values were similar to 1h PET measurements 1.63 [IQR, 1.37-1.98] vs. 1.55 [IQR, 1.43-1.89], P = 0.30 and the background activity was lower 0.71 [IQR, 0.65-0.81] vs. 1.24 [IQR, 1.05-1.31], p&lt;0.001. On 3h PET, the TBR values, cSUVmax and the noise were significantly higher (2.30 [IQR, 1.70-2.68] vs 1.28 [IQR, 0.98-1.56], p&lt;0.001; 0.38 [IQR, 0.27-0.70] vs 0.90 [IQR, 0.64-1.17], p&lt;0.001 and 0.10 [IQR, 0.09-0.12] vs. 0.07 [IQR, 0.06-0.09], P = 0.02). The median cSUVmax and TBR values increased by 92% (range: 33-225%) and 80% (range: 20-177%). Conclusion: Blood-pool activity decreases on delayed imaging facilitating the assessment of 18F-NaF uptake in coronary plaques. The median target to background ratios increase by 80% leading to the detection of more plaques with significant uptake compared to the standard 1h protocol. A greater than a 1h delay may improve the detection of 18F-NaF uptake in coronary artery plaques. ER -