In-vivo validation of videodensitometric coronary cross-sectional area measurement using dual-energy digital subtraction angiography

Abstract

Previous studies indicate that conventional geometric edge detection techniques, used in quantitative coronary arteriography (QCA), have significant limitations in quantitating coronary cross-sectional area of small diameter (D) vessels (D < 1.00 mm) and lesions with complex cross-section. As a solution to this problem, we have previously reported on an in-vitro validation of a videodensitometric technique that quantitates the absolute cross-sectional area including small vessel diameter (D < 1.00 mm) and any complex shape of the vessel cross-section. For in-vivo validation, plastic tubing (5-8 mm long) with different shape complex cross-section with known cross-sectional area (A = 0.8-4.5 mm2) were percutaneously wedged in the coronary arteries of anesthetized pigs (40-50 kg). Contrast material injections (6-10 ml at 2-4 ml/sec) were made into the left main coronary artery during image acquisition using a motion immune dual-energy subtraction technique, where low and high X-ray energy and filtration were switched at 30 Hz. A comparison was made between the actual and measured cross-sectional area using the videodensitometry and edge detection techniques in tissue suppressed energy subtracted images. In eighteen comparisons the videodensitometry technique produced significantly improved results (slope = 0.87, intercept = 0.24 mm2, r = 0.94) when compared to the edge detection technique (slope = 0.42, intercept = 1.99 mm2, r = 0.39). Also, a cylindrical vessel phantom (D = 1.00-4.75 mm) was used to test the ability to calculate and correct for the effect of the out of plane angle of the arterial segment on the cross-sectional area estimation of the videodensitometry technique. After corrections were made for the out of plane angle using two different projections, there was a good correlation between the actual and the measured cross-sectional area using the videodensitometry technique (slope = 0.91, intercept = 0.11 mm2, r = 0.99). These data suggest that it is possible to quantitate absolute cross-sectional area without any assumption regarding the arterial shape using videodensitometry in conjunction with the motion immune dual-energy subtraction technique.

Feasibility of real time dual-energy imaging based on a flat panel detector for coronary artery calcium quantification

“…Energy subtraction has been applied to the detection of calcium in pulmonary nodules, 12,13 bone mineral analysis, 14 and cardiac imaging. [15][16][17][18][19][20][21][22] Dual-energy subtraction, in conjunction with a flat panel detector, is now commercially available for chest radiography applications. 23 Real-time dual-energy imaging in conjunction with a flat panel detector ͑FPD͒ for cardiac imaging has not previously been investigated.…”

Quantification of Coronary Artery Lumen Volume by Digital Angiography

“…The volume measurements were performed with both the video densitometry and edgedetection algorithms. 13 In the edge-detection algorithm, the vessel edges were defined relative to the first-and second-derivative extrema of the vessel profile. 17 The diameter and length information measured with the edge-detection algorithm was used to calculate arterial volume assuming a circular cross section.…”

“…We have previously developed techniques that address these limitations. [12][13][14] In the present investigation, a video densitometry technique for quantification of coronary artery lumen volume has been validated both in vitro and in vivo in a swine animal model.…”

Effect of vessel orientation on videodensitometry quantitative coronary arteriography

“…Videodensitometry coronary arteriography is another method that can be used for quantification of vessel crosssectional area. [6][7][8][9][10][11][12][13] In this technique the vessel cross-sectional area is directly related to the integrated gray level under the vessel profile and is not affected by the system modulation transfer function. Furthermore, videodensitometry does not require any assumption regarding vessel shape and it can be used to measure lesions of complex lumen geometry.…”

“…14 On the other hand, the out-of-plane angle of the vessel centerline with respect to the face of the image intensifier can introduce large error in the measured cross-sectional area using videodensitometry coronary arteriography. 12 In this study, we investigate a technique to measure the out-of-plane angle of the vessel centerline with respect to the face of the image intensifier using biplane images. The outof-plane angle is then used to correct the cross-sectional area measurements using videodensitometry coronary arteriography.…”