Coronary CTA Plaque Quantification Linked to Impaired Myocardial Flow Reserve on CT Perfusion Imaging

A new study published in BMC Medical Imaging has revealed a striking connection between the composition of plaque in the coronary arteries and the heart’s ability to boost blood flow under stress. Researchers at the First Affiliated Hospital of Dalian Medical University found that the burden of low-attenuation plaque, a fatty component of arterial blockages visible on coronary computed tomography angiography, was independently associated with impaired myocardial flow reserve measured by CT myocardial perfusion imaging. The finding suggests that the character of plaque, not merely its size or the degree of arterial narrowing it causes, carries crucial information about the functional status of the heart’s blood supply.

The research team, led by Shuang Pan, Xueyan Hou, Ruili Qin, Zhiqiang Yang, Hao Wang, and Zhaoqian Wang, conducted a prospective study involving 399 patients with suspected stable coronary artery disease between April 2019 and October 2023. All participants underwent both coronary computed tomography angiography and CT myocardial perfusion imaging using a third-generation dual-source CT scanner. The median age of the cohort was 59.0 years, with an interquartile range of 53.0 to 65.5 years, and 295 patients, representing 73.9 percent of the sample, were male. Impaired global myocardial flow reserve, defined as a value below 1.84, was detected in 278 patients, accounting for 69.7 percent of the cohort.

Myocardial flow reserve represents the ratio of myocardial blood flow during pharmacological stress to blood flow at rest. It is a powerful functional indicator of how well the coronary circulation can respond to increased demand. A reduced myocardial flow reserve signals that the heart cannot adequately augment its blood supply, a condition that may result from obstructive stenosis, coronary microvascular dysfunction, or diffuse atherosclerotic disease. Although the relationship between coronary stenosis and myocardial perfusion is well established in the literature, the association between quantitative plaque parameters and myocardial perfusion has remained poorly understood until now.

Coronary computed tomography angiography allows radiologists to characterise plaque composition based on attenuation values measured in Hounsfield units. Low-attenuation plaque, typically defined as plaque with attenuation values below 30 Hounsfield units, corresponds to lipid-rich fibro-fatty and necrotic components. These components are considered markers of plaques that are more vulnerable to rupture. Calcified plaque, by contrast, reflects a more stable, chronic form of atherosclerosis. The study quantified both calcified and low-attenuation plaque burdens and examined how these parameters related to myocardial flow reserve derived from CT perfusion imaging.

The vessel-based analysis revealed that obstructive coronary artery disease, with a standardised coefficient of 0.761 and a P value below 0.001, calcified plaque burden, with a coefficient of 0.209 and a P value of 0.040, and low-attenuation plaque burden, with a coefficient of 0.219 and a P value of 0.019, were independently associated with impaired regional myocardial flow reserve. Obstructive coronary artery disease and low-attenuation plaque burden were also inversely associated with regional myocardial flow reserve as a continuous variable, indicating that greater plaque burden corresponded to progressively lower flow reserve values.

After adjusting for confounding factors, the patient-based analysis demonstrated that obstructive coronary artery disease, with a coefficient of 0.685 and a P value of 0.014, and low-attenuation plaque burden, with a coefficient of 0.339 and a P value of 0.008, remained independently associated with impaired global myocardial flow reserve. The persistence of these associations after multivariable adjustment strengthens the conclusion that low-attenuation plaque burden provides complementary information about myocardial flow reserve status beyond what is captured by traditional stenosis assessment alone.

The implications of these findings are substantial for clinical practice. Current risk stratification in coronary artery disease relies heavily on the degree of luminal stenosis, with obstructive narrowing typically prompting revascularisation decisions such as percutaneous coronary intervention or coronary artery bypass grafting. However, many patients with non-obstructive disease still experience adverse events, and some patients with obstructive stenosis remain asymptomatic. The study suggests that quantifying low-attenuation plaque burden from routine coronary CT angiography could refine risk stratification by identifying patients whose plaque composition places them at higher functional risk, even when luminal narrowing alone might not warrant intervention.

Low-attenuation plaque burden may serve as a marker for refining risk stratification in patients with coronary artery disease, according to the authors. The association between this quantitative plaque parameter and impaired myocardial flow reserve suggests that plaque composition reflects the underlying pathophysiology of ischaemia more faithfully than stenosis severity alone. This is particularly relevant for patients with ischaemia with no obstructive coronary artery disease, a condition abbreviated as INOCA, where traditional angiographic assessment fails to explain symptoms. Diffuse low-attenuation plaque may impair flow reserve without producing focal obstructive narrowing, and its quantification could help clinicians recognise these patients.

The study was approved by the Ethics Committee of the First Affiliated Hospital of Dalian Medical University and conducted in accordance with the Helsinki Declaration. Written informed consent was obtained from all participants for the collection and analysis of CT measurement data. The authors declared no competing interests, and the research received no external funding. The article is published open access under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, permitting non-commercial sharing and reproduction with appropriate credit to the original authors and source.

As coronary CT angiography and CT myocardial perfusion imaging become increasingly integrated into clinical workflows, the ability to derive both anatomical and functional information from a single imaging session offers significant promise. The finding that low-attenuation plaque burden from coronary CT angiography is independently associated with impaired myocardial flow reserve derived from CT perfusion imaging suggests that these two modalities, when combined, can provide a more comprehensive picture of coronary artery disease than either alone. This integrated approach may ultimately improve the identification of patients at risk of major adverse cardiovascular events and guide more personalised treatment decisions in the management of coronary artery disease.

Subject of Research: Association between plaque quantification from coronary CTA and myocardial flow reserve derived from CT myocardial perfusion imaging

Article Title: Association between plaque quantification from coronary CTA and myocardial flow reserve derived from CT myocardial perfusion imaging

Article References: Pan, S., Hou, X., Qin, R., Yang, Z., Wang, H., & Wang, Z. (2026). Association between plaque quantification from coronary CTA and myocardial flow reserve derived from CT myocardial perfusion imaging. BMC Medical Imaging. https://doi.org/10.1186/s12880-026-02750-0

Image Credits: AI Generated

DOI: 10.1186/s12880-026-02750-0

Keywords: Association, between, plaque, quantification, coronary, myocardial, flow, reserve, derived, perfusion, imaging, scientific research