Delayed 18F-fluorodeoxyglucose PET/CT imaging improves quantitation of atherosclerotic plaque inflammation: Results from the CAMONA study

• DOI: 10.1007/s12350-014-9884-6
• Publication Date: 2014-03-18T01:40:01Z
• Authors: Björn A. Blomberg; Anders Thomassen; Richard A.P. Takx; Malene G. Hildebr...; Jane A. Simonsen; Karen M. Buch-Olsen; Axel C.P. Diederi...; Hans Mickley; Abass Alavi; Poul F. Høilund-C...
• Keywords: Male; Adult; PET/CT; Tomography, X-Ray Computed/methods; Sensitivity and Specificity; 03 medical and health sciences; 0302 clinical medicine; Computer-Assisted/methods; vascular inflammation; Humans; Tomography; Image Interpretation; Image Interpretation, Computer-Assisted/methods; Reproducibility of Results; Middle Aged; Positron-Emission Tomography/methods; X-Ray Computed/methods; 3. Good health; Radiopharmaceuticals/administration & dosage; Fluorodeoxyglucose F18/administration & dosage; Female; atherosclerosis; Image Enhancement/methods; Multimodal Imaging/methods; Algorithms; Coronary Artery Disease/diagnostic imaging

This study aimed to determine if delayed 18F-fluorodeoxyglucose (18FDG) PET/CT imaging improves quantitation of atherosclerotic plaque inflammation. Blood-pool activity can disturb the arterial 18FDG signal. With time, blood-pool activity declines. Therefore, delayed imaging can potentially improve quantitation of vascular inflammation. 40 subjects were prospectively assessed by dual-time-point PET/CT imaging at approximately 90 and 180 minutes after 18FDG administration. For both time-points, global uptake of 18FDG was determined in the carotid arteries and thoracic aorta by calculating the blood-pool corrected maximum standardized uptake value (cSUVMAX). A target-to-background ratio (TBR) was calculated to determine the contrast resolution at 90 and 180 minutes. Furthermore, we assessed whether the acquisition time-point affected the relation between cSUVMAX and the estimated 10-year risk for fatal cardiovascular disease (SCORE %). A significant increase in carotid cSUVMAX (23%, P < .0001), carotid TBR (20%, P < .0001), aortic cSUVMAX (14%, P < .0001), and aortic TBR (20%, P < .0001) was observed with time. At 90 minutes, cSUVMAX did not relate to SCORE %, whereas at 180 minutes significant positive relations were observed between SCORE % and carotid (τ = 0.25, P = .045) and aortic (τ = 0.33, P = .008) cSUVMAX. Delayed 18FDG PET/CT imaging at 180 minutes improves quantitation of atherosclerotic plaque inflammation over imaging at 90 minutes. Therefore, the optimal acquisition time-point to assess atherosclerotic plaque inflammation lies beyond the advocated time-point of 90 minutes after 18FDG administration.