Assessment of cardiac volumes and left ventricular mass by cine computed tomography before and after mitral balloon commissurotomy

A knowledge-based cone-beam x-ray CT algorithm for dynamic volumetric cardiac imaging

With the introduction of spiral/helical multislice CT, medical x-ray CT began a transition into cone-beam geometry. The higher speed, thinner slice, and wider coverage with multislice/cone-beam CT indicate a great potential for dynamic volumetric imaging, with cardiac CT studies being the primary example. Existing ECG-gated cardiac CT algorithms have achieved encouraging results, but they do not utilize any time-varying anatomical information of the heart, and need major improvements to meet critical clinical needs. In this paper, we develop a knowledge-based spiral/helical multislice/cone-beam CT approach for dynamic volumetric cardiac imaging. This approach assumes the relationship between the cardiac status and the ECG signal, such as the volume of the left ventricle as a function of the cardiac phase. Our knowledge-based cardiac CT algorithm is evaluated in numerical simulation and patient studies. In the patient studies, the cardiac status is estimated initially from ECG data and subsequently refined with reconstructed images. Our results demonstrate significant image quality improvements in cardiac CT studies, giving clearly better clarity of the chamber boundaries and vascular structures. In conclusion, this approach seems promising for practical cardiac CT screening and diagnosis.

Reproducibility of right and left ventricular volume measurements by electron-beam CT in patients with congestive heart failure

The applicability and reproducibility of electron-beam computed tomography (EBCT) was tested to define left and right ventricular volumes in patients with congestive heart failure in a clinical setting.

METHODS

Ten patients (mean age 64 +/- 11 years) with dilated hearts and stable congestive heart failure (functional class III-IV) were studied. After determination of the individual circulation time, two serial short axis polytomographic EBCT studies were performed within a mean interval of 14.8 +/- 10 days. Following intravenous contrast administration, biventricular end-diastolic volumes (LVEDV, RVEDV), end-systolic volumes (LVESV, RVESV), and left ventricular muscle mass (LVMM) were determined using previously developed techniques.

RESULTS

Adequate contrast opacification in both ventricular cavities was obtained in all patients at baseline and at follow-up. Values were 323.4 +/- 99.3 (mean +/- SD) and 332.6 +/- 105.4 ml for LVEDV, 249.3 +/- 75.6 and 250.5 +/- 79.3 ml for LVESV, 236.8 +/- 56.2 and 251.2 +/- 72.7 ml for RVEDV, 179.8 +/- 76.4 and 188.3 +/- 64.0 ml for RVESV, and 207.7 +/- 70.6 and 204.9 +/- 81.9 g for LVMM (p = NS, respectively, paired t-test). Linear regression analysis correlating biventricular volumes and left ventricular muscle mass measurements in the serial scans yielded r-values in the range of 0.89 to 0.95 and a small SEE. The SE of the mean differences between left and right ventricular ejection fraction measurements was 1 point, respectively.

CONCLUSION

EBCT studies of ventricular volumes in patients with dilated hearts and congestive heart failure are highly reproducible and offer the potential for serial assessment of these patients in whom quantitation of ventricular volumes has been shown to be of prognostic value.

Left ventricular filling and ejection fraction after successful percutaneous balloon mitral valvuloplasty

The effect of percutaneous balloon mitral valvuloplasty (PBMV) on left ventricular (LV) filling and ejection fraction (EF) still remains controversial. We evaluated LV filling and EF in 23 patients (19 women and four men, mean age 35.6+/-9.6, range 17-56 years) with mitral stenosis (MS) and sinus rhythm immediately before and after successful PBMV not complicated with significant mitral regurgitation and arrhythmia during left ventriculography. After PBMV mean mitral valve area increased from 1.4+/-0.2 to 2.2+/-0.3 cm2 (P<0.01), mean mitral valve gradient (MVG) decreased from 18.6+/-5.7 to 6.9+/-3.2 mmHg (P<0.01) and mean left atrial pressure (LAP) decreased from 26.0+/-8.2 to 12.3+/-5.2 mmHg (P<0.01). We did not determine any change in EF (before PBMV 61.8+/-9.3% and after PBMV 61.8+/-7.6% (P>0.05)). Heart rate did not change significantly before and after valvuloplasty (P>0.05). Despite the decrease in LAP and MVG, the early diastolic filling fraction of left ventricle did not change (before PBMV 59.5+/-7.5%, after PBMV 57.8+/-8.9% (P>0.05)). Also, we did not determine any increase in LV end diastolic volume index (before PBMV 89.9+/-27.7 cm3/m2 and after PBMV 84.6+/-20.9 cm3/m2 (P>0.05)). However, LV end diastolic pressure increased significantly after PBMV (from 6.6+/-3.0 to 11.3+/-4.9 mmHg (P<0.01)). We conclude that in patients with MS, LV diastolic performance is impaired and LV EF does not change acutely after PBMV.