Relationship between changes in pericoronary adipose tissue attenuation and coronary plaque burden quantified from coronary computed tomography angiography

Abstract

Aims Increased attenuation of pericoronary adipose tissue (PCAT) around the proximal right coronary artery (RCA) from coronary computed tomography angiography (CTA) has been shown to be associated with coronary inflammation and improved prediction of cardiac death over plaque features. Our aim was to investigate whether PCAT CT attenuation is related to progression of coronary plaque burden. Methods and results We analysed CTA studies of 111 stable patients (age 59.2 ± 9.8 years, 77% male) who underwent sequential CTA (3.4 ± 1.6 years between scans) with identical acquisition protocols. Total plaque (TP), calcified plaque (CP), non-calcified plaque (NCP), and low-density non-calcified plaque (LD-NCP) volumes and corresponding burden (plaque volume × 100%/vessel volume) were quantified using semi-automated software. PCAT CT attenuation (HU) was measured around the proximal RCA, the most standardized method for PCAT analysis. Patients with an increase in NCP burden (n = 51) showed an increase in PCAT attenuation, whereas patients with a decrease in NCP burden (n = 60) showed a decrease {4.4 [95% confidence interval (CI) 2.6–6.2] vs. −2.78 (95% CI −4.6 to −1.0) HU, P < 0.0001}. Changes in PCAT attenuation correlated with changes in the burden of NCP (r = 0.55, P < 0.001) and LD-NCP (r = 0.24, P = 0.01); but not CP burden (P = 0.3). Increased baseline PCAT attenuation ≥−75 HU was independently associated with increase in NCP (odds ratio 3.07, 95% CI 1.4–7.0; P < 0.008) and TP burden on follow-up CTA. Conclusion PCAT attenuation measured from routine CTA is related to the progression of NCP and TP burden. This imaging biomarker may help to identify patients at increased risk of high-risk plaque progression and allow monitoring of beneficial changes from medical therapy.

Towards reference values of pericoronary adipose tissue attenuation: impact of coronary artery and tube voltage in coronary computed tomography angiography

“…The majority of PCAT MA studies about relationship with CAD focused on analysis of the RCA alone, while the LAD and LCX could provide additional information and increase the accuracy of outcome prediction [16,21]. Our study focused on PCAT MA measurements in all three coronary arteries, showing that PCAT MA was slightly but significantly different between the LAD, LCX, and RCA.…”

“…Higher kV voltages will inherently lead to higher PCAT MA and EAT attenuation, unrelated to a pathophysiological process. Prior studies investigating the use of PCAT MA used cCTA images obtained at 100 kV and/or 120 kV [16,20,21,25]. However, lower kV acquisitions are becoming increasingly popular in order to reduce radiation and contrast medium volume.…”

“…To analyze all three coronary arteries, an adjusted measurement method was used in our study. Previously, a measurement length of 40 mm was used [16,21,25] which was feasible for the RCA because it has fewer side branches and proximal variations than the LAD and LCX. To avoid influence of side branches, measurement length was reduced from 40 to 10 mm in this study.…”

“…PCAT MA measurement width around the coronary could potentially affect measurement accuracy. Prior studies measured PCAT MA using approximately 3 mm thickness (or equal to vessel diameter) around the coronary vessels [16,20,21,25]. However, contrast enhancement of the lumen has been found to influence the HU values in the voxels adjacent to the luminal border [32].…”

“…Thus, PCAT could potentially be used as a non-invasive proxy to assess coronary inflammation based on routine cCTA imaging, and could offer valuable information for early diagnosis, treatment, and prevention of CAD. Several studies explored the diagnostic value of PCAT MA in patients with plaques [20][21][22][23][24]. However, studies including patients without plaque so far mainly focused on the healthy RCA in small cohorts of patients.…”