Iodinated Contrast Opacification Gradients in Normal Coronary Arteries Imaged With Prospectively ECG-Gated Single Heart Beat 320-Detector Row Computed Tomography

Abstract

Background-To define and evaluate coronary contrast opacification gradients using prospectively ECG-gated single heart beat 320-detector row coronary angiography (CTA). Methods and Results-Thirty-six patients with normal coronary arteries determined by 320ϫ0.5-mm detector row coronary CTA were retrospectively evaluated with customized image postprocessing software to measure Hounsfield Units at 1-mm intervals orthogonal to the artery center line. Linear regression determined correlation between mean Hounsfield Units and distance from the coronary ostium (regression slope defined as the distance gradient G d ), lumen cross-sectional area (G a ), and lumen short-axis diameter (G s ). For each gradient, differences between the 3 coronary arteries were analyzed with ANOVA. Linear regression determined correlations between measured gradients, heart rate, body mass index, and cardiac phase. To determine feasibility in lesions, all 3 gradients were evaluated in 22 consecutive patients with left anterior descending artery lesions Ն50% stenosis. For all 3 coronary arteries in all patients, the gradients G a and G s were significantly different from zero (PϽ0.0001), highly linear (Pearson r values, 0.77 to 0.84), and had no significant difference between the left anterior descending, left circumflex, and right coronary arteries (PϾ0.503). The distance gradient G d demonstrated nonlinearities in a small number of vessels and was significantly smaller in the right coronary artery when compared with the left coronary system (PϽ0.001). Gradient variations between cardiac phases, heart rates, body mass index, and readers were low. Gradients in patients with lesions were significantly different (PϽ0.021) than in patients considered normal by CTA. Conclusions-Measurement of contrast opacification gradients from temporally uniform coronary CTA demonstrates feasibility and reproducibility in patients with normal coronary arteries. For all patients, the gradients defined with respect to the coronary lumen cross-sectional area and short-axis diameters are highly linear, not significantly influenced by the coronary artery (left anterior descending artery versus left circumflex versus right coronary artery), and have only small variation with respect to patient parameters. Preliminary evaluation of gradients across coronary artery lesions is promising but requires additional study. (Circ Cardiovasc Imaging. 2010;3:179-186.)

Diagnostic performance of transluminal attenuation gradient and fractional flow reserve by coronary computed tomographic angiography (FFRCT) compared to invasive FFR: a sub-group analysis from the DISCOVER-FLOW and DeFACTO studies

“…TAG is a novel method developed to assess the hemodynamic significance of CAD and is calculated using a linear regression model of luminal contrast attenuations in a coronary vessel obtained by manual or semi-automated techniques [9,10,[19][20][21][22]. To date, several studies have examined the relation of TAG to invasive FFR and have shown a variety in the diagnostic accuracy of TAG in predicting lesion-specific ischemia by invasive FFR \0.80.…”

Submillisievert Median Radiation Dose for Coronary Angiography with a Second-Generation 320–Detector Row CT Scanner in 107 Consecutive Patients

“…Wide-volume scanners with 320 detector rows and up to 16 cm of cranial-caudal coverage enable wholeheart coverage at one acquisition time point (within one heartbeat or volume), which eliminates "stair-step" or misalignment artifacts (11)(12)(13) but also permits uniform attenuation when evaluating the coronary arteries, when analyzing myocardial perfusion defects (14,15), or when measuring contrast attenuation gradients across atherosclerotic lesions (16). Radiation doses are lower with wide-area detector scanners owing to shorter scanning times and reduction of redundant radiation from either overlapping of sequential axial scans or helical oversampling (13).…”

“…and heart rates at lower radiation doses compared with previous-generation CT scanners. This technology could further facilitate CT stress perfusion (14,15), contrast attnenuation gradients across atherosclerotic lesions (16), and noninvasive fractional flow reserve computed from coronary CT angiography (39).…”

Automatic detection of aorto-femoral vessel trajectory from whole-body computed tomography angiography data sets

“…This method is based on the assumption that the HU value (intensity) along the artery should be a smooth gradual decreasing curve when this artery is without the presence of calcium [16].…”