A 40-year-old male patient (1.8 m, 68 kg, BMI= 21) with a prosthetic valve (1981) and suffering from ascending aorta dilatation since 2006 was referred for a Trans-Thoracic Echocardiography (TTE) with Doppler. The exam demonstrated good functioning of the Bjork prosthesis valve but a dilatation of the aortic root was measured at 59 mm on the Vasalva sinus and maximum diameter of the ascending aorta at 47 mm. A moderate mitral insufficiency was also noticed. The left ventricle is dilated with moderate hypertrophy and normal global systolic function. A new surgery is planned and the patient was referred to Cath-lab in order to evaluate the coronary arteries prior to surgery. The Left Anterior Descending Artery (LAD) was normal but catheterization of the Right Coronary Artery (RCA) was not possible. The patient was therefore referred to Cardiac CT (Figure 1).

Injection protocol:

Three phase injection using a dual head injector

• 80 ml of iodine contrast @ 5 cc/sec
• 30 ml of contrast media @ 2cc/sec
• + 30 ml of isotonic solution @ 2cc/sec
• 20 ml of saline flush @ 2.5 cc/sec
• Iodine concentration: 350 mg/ml

Dose:

• DLP: 684.08 mGy.cm
• Dose: 11.6 mSv*

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Figure 2: Aorta study with VesselIQ™ Xpress

AORTA STUDY

The CT exam and the automatic measurements given by the new VesselIQ™ Xpress (GE Healthcare) software, confirm the ascending aorta dilatation (Figures 2 & 3). This software tracks the middle of the lumen and automatically segments the aorta. It displays a curved and cross-section views of this vessel providing simultaneously its contour and measurements of diameter and area.

The ascending aorta is quantified at 59.5 mm* 58.5 mm at the Vasalva sinus and 47mm*46mm on its middle part in front of the pulmonary trunk.

Figure 4: Coronary tree and Aorta in Volume Rendering.

CORONARY ASSESSMENT

The CT exam demonstrates a left-dominant heart with a very tiny Right Coronary Artery (RCA) giving off two marginal branches (Figure 4). These arteries are normal without significant stenosis (Figures 5 & 6).

Figure 9: Curved view of the LAD.

The Left Anterior Descending (LAD) artery and its diagonal branches are of normal aspect (Figures 9 & 10), except a small mixed plaque on LAD segment I without significant stenosis (Figure 11).

The Left Circumflex (LCx) artery and the Left Marginal branches are normal without significant stenosis (Figures 12 & 13).

Figure 13: Curved views of the Left Marginal branches

The CT exam of this patient and the analysis with VesselIQ™ Xpress software confirmed the measurements given by TTE exam. It also provided accurate information on the coronary arteries before surgery where cardiac catheterization of the RCA was not possible.