The presence and severity of aortic valve calcifications were assessed on double oblique transverse reconstructions. The degree of aortic valve calcification was graded as follows: grade 1—no calcification; grade 2—mildly calcified (small isolated spots); grade 3—moderately calcified (multiple larger spots); grade 4—heavily calcified (extensive calcification of all cusps). Extensive calcifications may hamper the ability to cross the native valve during percutaneous aortic valve replacement. Therefore, multislice computed tomography may provide important information in the selection of potential candidates.

The anatomy of the aortic root was assessed on 3 reconstructed views. The coronal view (A) is similar to the anterior-posterior view on aortic root angiography. The reconstructed single oblique sagittal (B) view has the same orientation as the parasternal long-axis view on transthoracic echocardiogram and the mid-esophageal long-axis view on transesophageal echocardiogram. The reconstructed double oblique transverse view (C) is parallel to the plane of the aortic root. See Table 1 for detailed description of the variables.

On the coronal view, the maximal diameter of the sinus of Valsalva was assessed (indicated by the double arrow). In addition, the distance between the aortic annulus (indicated by the dotted line) and the level of the maximal diameter of the sinus were assessed on the coronal view. These variables are important to assess before percutaneous aortic valve replacement, because they have implications for prosthesis sizing.

Coronary ostium occlusion may occur after percutaneous aortic valve replacement. Therefore, it is important to assess the relation between the ostia of the coronary arteries and the coronary leaflet length. With the use of a coronal view, the distance between the annulus and the ostia of the coronary arteries, and the length of the coronary leaflets were assessed. This figure demonstrates the measurements of the distance between the annulus and the ostium of the left coronary artery, and the measurement of the left coronary leaflet length.

For percutaneous aortic valve replacement, it is important to assess the distance between the ostia of the coronary arteries and the coronary leaflets, because this may determine the risk of coronary occlusion. On the coronal view, the distance between the tip of the left coronary leaflet and the ostium of the left coronary artery was assessed in diastole and systole.

A single oblique sagittal view was used to assess the largest diameter of the interventricular septum and to grade the aspect of the interventricular septum as normal or sigmoid. In this patient, accurate positioning of the percutaneous aortic valve may be hampered by the small diameter of the left ventricular outflow tract (indicated by the double arrow). Therefore, multislice computed tomography can provide valuable information on the aspect of the left ventricular outflow tract and the septum prior to percutaneous valve procedures. Also, note the post-stenotic dilatation of the ascending aorta, indicated by the dotted arrow in this patient.

Bland-Altman plot analysis revealed a good agreement between multislice computed tomography (MSCT) and echocardiography (ECHO) for the assessment of aortic annulus diameter. The difference between each pair (y axis) is plotted against the average value of the same pair (x axis). Mean difference was 1.9 mm (solid line), 95% confidence interval –2.8 to 6.6 mm (dotted lines).

Panels A and B demonstrate an example of a patient with an oval shape of the aortic annulus. The diameter of the aortic annulus on the coronal view (A) was 27.3 mm, whereas the annulus diameter on the sagittal view (B) was 20.3 mm. A significant oval shape of the aortic annulus may increase the risk of paravalvular leakage after percutaneous aortic valve replacement. Panel C demonstrates a patient in which the length of the coronary leaflet exceeded the distance between the aortic annulus and the ostium of the left coronary leaflet (distances were 13.4 and 11.6 mm, respectively). There is an increased risk of coronary occlusion by the coronary leaflet or the prosthesis sealing annular cuff in these patients.