Grading of aortic valve stenosis at 64-slice spiral computed tomography: comparison with transthoracic echocardiography and calibration against cardiac catheterization.

PURPOSE: We sought to determine the accuracy of multislice spiral computed tomography (MSCT) for assessing of aortic valve stenosis and to establish threshold values of the planimetric aortic valve orifice area (AVA) that best separate between different grades of stenosis severity. MATERIALS AND METHODS: A total of 202 patients (among them 160 patients with aortic valve stenosis) underwent MSCT, transthoracic echocardiography (TTE) and cardiac catheterization (CATH). Planimetric AVA measurements at MSCT were compared with calculations based on Doppler flow velocity measurements by TTE (using the continuity equation) and pressure gradient measurements by CATH (using the Gorlin formula). RESULTS: Series of AVA measurements correlated well between MSCT and TTE (r = 0.86) and between MSCT and CATH (r = 0.90). However, AVA at MSCT (0.98 +/- 0.47 cm) was significantly larger than AVA at TTE (0.81 +/- 0.36 cm; P < 0.05) and CATH (0.80 +/- 0.39 cm; P < 0.05). For severity grades 0 through IV the AVAs at MSCT were 2.69 +/- 0.75, 1.86 +/- 0.30, 1.48 +/- 0.17, 0.95 +/- 0.20, and 0.68 +/- 0.20 cm, respectively. For separating, the 5 severity grades optimal thresholds at MSCT were 2.1, 1.6, 1.2, and 0.9 cm. Using these adjusted thresholds there was perfect agreement in classification between MSCT and CATH in 156 (77%), but a mismatch by 1 grade in 43 (21.5%) and 2 grades in 3 (1.5%) patients (kappaw = 0.86). CONCLUSION: Planimetric AVA measurements on MSCT allows for an accurate grading of aortic valve stenosis severity. However, AVA measurements on MSCT are usually larger than measurements on TTE and CATH. Consequently, the thresholds for discriminating between different severity grades have to be adjusted in MSCT.

Evaluation of left and right ventricular diastolic function by electron-beam computed tomography in patients with passive epicardial constraint.

OBJECTIVE: Previous investigations have shown the usefulness of electron-beam computed tomography (EBCT) to describe ventricular diastolic function and to detect constrictive filling pattern. We used EBCT to analyze diastolic function in patients who underwent passive epicardial constraint because data describing ventricular filling in these patients are still incomplete. METHODS: Ten patients with dilated cardiomyopathy (group 1) underwent EBCT examination before and again 6 months after surgery. Ten patients with normal diastolic function (group 2) and 5 male patients with constrictive pericarditis (group 3) served for comparison. Volume-time curves throughout the entire diastole were generated, and the rapidity of diastolic filling was assessed by calculating the percent filling fraction at consecutive EBCT frames throughout the diastole. Pericardial thickness was measured in a standardized fashion at different locations around both ventricles. RESULTS: Early left ventricular filling pattern in group 1 did not change postoperatively (filling fraction at third diastolic frame was 50.0 +/- 15.4% and 53.8 +/- 14.4% before and after surgery, respectively) and was not significantly different from group 2 (48.7 +/- 8.5%). In contrast, in group 3, early left ventricular filling was significantly accelerated (71.4 +/- 9.3%) when compared with groups 1 and 2. A similar pattern was observed for the right ventricle. Pericardial thickness between groups 1 (1.22 +/- 4.22 and 1.43 +/- 0.39 mm before and after surgery, respectively) and 2 (1.38 +/- 0.43 mm) did not differ significantly. In contrast, pericardium in group 3 was significantly thickened (4.93 +/- 1.11 mm) when compared with both groups 1 and 2. CONCLUSIONS: The EBCT identified an abnormal accelerated diastolic filling and thickened pericardium in patients with constrictive pericarditis. Conversely, a normal diastolic filling pattern and pericardial thickness seem to be preserved in patients after passive epicardial constraint, when compared with baseline values and with normal subjects.