Quantification of fractional flow reserve based on angiographic image data.

Coronary angiography provides excellent visualization of coronary arteries, but has limitations in assessing the clinical significance of a coronary stenosis. Fractional flow reserve (FFR) has been shown to be reliable in discerning stenoses responsible for inducible ischemia. The purpose of this study is to validate a technique for FFR quantification using angiographic image data. The study was carried out on 10 anesthetized, closed-chest swine using angioplasty balloon catheters to produce partial occlusion. Angiography based FFR was calculated from an angiographically measured ratio of coronary blood flow to arterial lumen volume. Pressure-based FFR was measured from a ratio of distal coronary pressure to aortic pressure. Pressure-wire measurements of FFR (FFR( P )) correlated linearly with angiographic volume-derived measurements of FFR (FFR( V )) according to the equation: FFR( P ) = 0.41 FFR( V ) + 0.52 (P-value < 0.001). The correlation coefficient and standard error of estimate were 0.85 and 0.07, respectively. This is the first study to provide an angiographic method to quantify FFR in swine. Angiographic FFR can potentially provide an assessment of the physiological severity of a coronary stenosis during routine diagnostic cardiac catheterization without a need to cross a stenosis with a pressure-wire.

Reproducibility of breast arterial calcium mass quantification using digital mammography.

RATIONALE AND OBJECTIVES: Breast arterial calcification (BAC) detected on mammography is frequently not included in final reports. However, previous studies have indicated that BAC may be evidence of general atherosclerotic vascular disease, and it can potentially be a useful marker of coronary artery disease. In addition, there are currently no available techniques for the quantification of calcium mass using mammography. The purpose of this study was to evaluate the reproducibility and inter-reader agreement of a technique for the quantification of BAC using standard digital mammography. MATERIALS AND METHODS: BAC mass was measured in a convenient, consecutive sample of 39 women aged 49 to 82 years attending routine mammographic examinations. BAC mass measurements were performed in standard mediolateral oblique (MLO) and craniocaudal (CC) views. To assess reproducibility, the BAC measurements obtained in MLO and CC views were compared. RESULTS: The measured BAC masses in CC (M(CC)) and MLO (M(MLO)) projections were related by M(CC) = 0.82(M(MLO)) + 0.27 mg (r = 0.97; standard error of estimation [SEE], 3.44 mg). The measured BAC masses in the left (M(L)) and right (M(R)) breasts were related by M(L) = 0.86(M(R)) - 0.06 mg (r = 0.95; SEE, 4.30 mg). The intraclass correlation coefficients for the measurement of calcium mass ranged from 0.94 in the left CC view to 0.99 in the right CC view. CONCLUSION: A densitometry technique for the quantification of BAC mass was evaluated in patients using standard full-field digital mammography. The results demonstrated that this densitometric technique for the quantification of BAC mass is highly reproducible and has excellent inter-reader agreement. This technique may provide a quantitative metric for future studies relating the severity of BAC and cardiovascular risk.