Salah D. Qanadli

Variability of ascending aorta diameter measurements as assessed with electrocardiography-gated multidetector computerized tomography and computer assisted diagnosis software

Recently, morphometric measurements of the ascending aorta have been done with ECG-gated multidector computerized tomography (MDCT) to help the development of future novel transcatheter therapies (TCT); nevertheless, the variability of such measurements remains unknown. Thirty patients referred for ECG-gated CT thoracic angiography were evaluated. Continuous reformations of the ascending aorta, perpendicular to the centerline, were obtained automatically with a commercially available computer aided diagnosis (CAD). Then measurements of the maximal diameter were done with the CAD and manually by two observers (separately). Measurements were repeated one month later. The Bland-Altman method, Spearman coefficients, and a Wilcoxon signed-rank test were used to evaluate the variability, the correlation, and the differences between observers. The interobserver variability for maximal diameter between the two observers was up to 1.2 mm with limits of agreement [-1.5, +0.9] mm; whereas the intraobserver limits were [-1.2, +1.0] mm for the first observer and [-0.8, +0.8] mm for the second observer. The intraobserver CAD variability was 0.8 mm. The correlation was good between observers and the CAD (0.980-0.986); however, significant differences do exist (P<0.001). The maximum variability observed was 1.2 mm and should be considered in reports of measurements of the ascending aorta. The CAD is as reproducible as an experienced reader.

An accurate and reproducible scheme for quantification of coronary artery calcification in CT scans

The coronary artery disease is a major cause of deaths in the western world. One indicator for coronary artery disease (CAD) is coronary artery calcification (CAC). An accurate and reproducible scheme is desired to monitor the progression of patients coronary calcification in follow-up studies. Traditional approaches for CAC estimation lack to provide accurate and reproducible results. In This work, a new adaptive and stochastic 3D method has been proposed by employing a modified expectation-maximisation (MEM) algorithm. It is less sensitive to partial volume effects, motion effects, slice thickness and low dose. Accuracy of the proposed method was measured by a cardiac CT stationary phantom containing 6 calcium inserts of predetermined size and density that were scanned 90 times using 15 different protocols based on slice thickness and radiation. Reproducibility was measured in 35 patients who were each scanned twice with the patient being repositioned before the second scan. Compared with the Agatston based method, it is shown that the proposed algorithm gives better results in terms of accuracy and reproducibility.

Aortic Bicuspidia, Silent Ductus Arteriosus

The bicuspid aortic valve (BAV) is the most common congenital cardiac anomaly, occurring in 1% to 2% of the general population (Fedak et al. 2002). Although the physiopathology and natural history are not completely understood, the bicuspid aortic valve syndrome (BAVS) is a clinically challenging issue for physicians and more recently for radiologists. It has been demonstrated that the majority of patients with BAVS develop signifi cant anatomic changes and complications that require specifi c treatment. Thus, recognition of the silent disease could have signifi cant implications for patient management. This section will focus on anatomic features of the BAV, assessment of the bicuspidia, especially using relatively new cross-sectional modalities, and identifi cation of cardiac and vascular complications.