Relationship Between 18F-fluorodeoxyglucose Uptake on Positron Emission Tomography and Aortic Calcification.

Introduction: Although 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) has been widely utilized to assess the extent of inflammation, the association between the extent and severity of atherosclerosis and 18F-FDG uptake on PET remains unexamined. The current study aimed to investigate whether aortic calcium (AC) scores were associated with increased aortic uptake of 18F-FDG on PET. Methods: A total of 167 consecutive patients with suspected lung cancer but unproven malignancy who underwent non-contrast-enhanced computed tomography (CT) and 18F-FDG PET/CT were enrolled. The average standardized uptake values in the ascending aorta were used to calculate the target-to-background ratio (Mean TBR). The total (thoracic and abdominal) AC scores were measured on non-contrast-enhanced chest and abdominal CT using the Agatston method, and were categorized into three groups (0, 1-399, and ≥400). The relationship between total AC scores and 18F-FDG uptake in the ascending aorta was assessed using multivariate linear regression analysis. Results: In total, 68.26% were male, and a mean age was 67.10±14.70 years. Mean TBR values increased progressively with total AC score 0, 1-399, and ≥400 (1.01±0.07, 1.08±0.09, and 1.11±0.11, respectively; p<0.00001). Multivariate linear regression analysis revealed that increased total AC scores of 1-399 (ß=0.06, 95% CI: 0.01-0.11, p=0.02) and ≥400 (ß=0.11, 95% CI: 0.06-0.16, p<0.001) were significantly associated with higher Mean TBR. Conclusions: The current study demonstrated that total AC scores were associated with Mean TBR. Patients with a greater extent and severity of aortic calcifications may possess increased atherosclerotic inflammatory activity as measured by 18F-FDG PET/CT.

Associations of adipokine levels with the prevalence and extent of valvular and thoracic aortic calcification: The Multi-Ethnic Study of Atherosclerosis (MESA).

BACKGROUND AND AIMS: Extra-coronary calcification (ECC) is a marker of atherosclerosis and independently associated with cardiovascular disease (CVD). Adipokines may mediate the effect of obesity on atherosclerosis. However, the relationship of adipokines with ECC is not well-established. We examined the associations of leptin, resistin and adiponectin with ECC in a diverse community-based cohort. METHODS: We performed a cross-sectional analysis of 1897 adults without clinical CVD in the MESA cohort. Serum adipokine levels and non-contrast cardiac CT scans were obtained at Exam 2 or 3 (randomly assigned). ECC was quantified by Agatston score and included calcification of the mitral annulus (MAC), aortic valve (AVC), ascending thoracic aorta (ATAC) and descending thoracic aorta (DTAC). We used multivariable regression to evaluate the associations between leptin, resistin and adiponectin [per 1 SD ln(adipokine] with ECC prevalence (score >0) and extent [ln(score+1)]. RESULTS: The mean age of participants was 65 ± 10 years; 49% women. After adjusting for demographic factors, adiponectin was inversely associated with AVC prevalence and extent; leptin positively associated with MAC prevalence and extent; and resistin positively associated with ATAC prevalence and extent and DTAC extent. After adjustment for BMI and other CVD risk factors, adiponectin remained inversely associated with AVC prevalence, and resistin remained associated with greater ATAC prevalence and extent. Leptin was not associated with measures of ECC after full adjustment. No adipokine was associated with MAC after full adjustment. CONCLUSIONS: We identified significant associations between select adipokines and specific markers of ECC. Adipokines may play a role in the development of systemic atherosclerosis.

A methodology review on the incremental prognostic value of computed tomography biomarkers in addition to Framingham risk score in predicting cardiovascular disease: the use of association, discrimination and reclassification.

BACKGROUND: Computed tomography (CT) biomarkers claim to improve cardiovascular risk stratification. This review focuses on significant differences in incremental measures between adequate and inadequate reporting practise. METHODS: Studies included were those that used Framingham Risk Score as a baseline and described the incremental value of adding calcium score or CT coronary angiogram in predicting cardiovascular risk. Searches of MEDLINE, EMBASE, Web of Science and Cochrane Central were performed with no language restriction. RESULTS: Thirty five studies consisting of 206,663 patients (men = 118,114, 55.1%) were included. The baseline Framingham Risk Score included the 1998, 2002 and 2008 iterations. Selective reporting, inconsistent reference groupings and thresholds were found. Twelve studies (34.3%) had major and 23 (65.7%) had minor alterations and the respective Δ AUC were significantly different (p = 0.015). When the baseline model performed well, the Δ AUC was relatively lower with the addition of a CT biomarker (Spearman coefficient = - 0.46, p < 0.0001; n = 33; 76 pairs of data). Other factors that influenced AUC performance included exploration of data analysis, calibration, validation, multivariable and AUC documentation (all p < 0.05). Most studies (68.7%) that reported categorical NRI (n = 16; 46 pairs of data) subjectively drew strong conclusions along with other poor reporting practices. However, no significant difference in values of NRI was found between adequate and inadequate reporting. CONCLUSIONS: The widespread practice of poor reporting particularly association, discrimination, reclassification, calibration and validation undermines the claimed incremental value of CT biomarkers over the Framingham Risk Score alone. Inadequate reporting of discrimination inflates effect estimate, however, that is not necessarily the case for reclassification.