Combined non-contrast enhancement 3D bright-blood and 2D black-blood coronary magnetic resonance angiography for the assessment of coronary artery stenosis.

BACKGROUND

Non-contrast coronary magnetic resonance angiography (CMRA) offers a radiation- and contrast-free alternative for evaluating coronary artery disease, yet its clinical adoption has been constrained by suboptimal specificity, primarily due to flow-related artifacts and signal loss inherent to bright-blood imaging. Black-blood vessel wall imaging, by suppressing intraluminal blood signal, enables direct visualization of the coronary wall and may complement bright-blood CMRA to improve diagnostic accuracy. However, the additive value of a targeted sequential protocol combining these two techniques remains to be established. The objective of this study was to evaluate whether a sequential protocol combining three-dimensional (3D) bright-blood CMRA with lesion-directed two-dimensional (2D) black-blood coronary magnetic resonance (CMR) improves the diagnostic performance of non-contrast CMRA for detecting coronary artery stenosis, using computed tomography angiography as the reference standard.

METHODS

From January 2025 to April 2025, consecutive patients with suspected coronary artery disease who were scheduled for dual-source computed tomography angiography and consented to undergo 3.0-T non-contrast CMRA were enrolled. The imaging protocol comprised free-breathing 3D bright-blood whole-heart CMRA, followed by lesion-directed 2D black-blood CMRA performed exclusively in segments with equivocal or suspicious findings on bright-blood imaging. Coronary computed tomography angiography (CCTA) served as the primary reference standard, with ICA performed in a subset of nine patients. Diagnostic performance for detecting significant (>50% diameter stenosis) and mild (25-49%) stenosis was assessed on a per-segment basis. Comparative analyses between bright-blood CMRA alone and the combined approach were performed using the McNemar test for paired proportions and DeLong's method for receiver operating characteristic (ROC) curves.

RESULTS

A total of 114 vessel segments from 104 patients (mean age 63±13 years; 63 men)were included in the final analysis. The combination of bright-blood CMRA and 2D black-blood CMR demonstrated superior diagnostic performance compared with bright-blood CMRA alone for identifying significant stenosis (>50% diameter stenosis). Sensitivity was 97.9% [95% confidence interval (CI), 88.9-99.9%] versus 87.5% (95% CI, 72.3-93.9%; P=0.031), specificity was 98.5% (95% CI, 91.8-100.0%) versus 68.1% (95% CI, 52.4-76.5%; P<0.001), accuracy was 98.2% (95% CI, 93.8-99.8%) versus 76.3% (95% CI, 64.6-81.5%; P<0.001), and the area under the receiver operating characteristic curve (AUC) was 0.98 (95% CI, 95.2-99.1%) versus 0.75 (95% CI, 66.2-82.1%; P<0.001). In addition, the combined approach correctly identified non-significant stenosis (25-49% diameter stenosis) in 32 of 35 segments and significantly improved sensitivity [91.4% (95% CI, 76.8-98.0%) vs. 71.4% (95% CI, 53.7-85.4%); P=0.039].

CONCLUSIONS

The combination of 3D bright-blood CMRA and 2D black-blood CMR significantly enhances the diagnostic performance of non-contrast CMRA for detecting both significant and mild coronary artery stenosis.