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Background: Multislice helical computed tomography (MSCT) has been used to depict coronary anatomy noninvasively, and proved useful for evaluating ventricular function. The aim of our study was to assess the accuracy of ventricular volume as measured by MSCT., Methods: Fourteen human left ventricular (LV) and 15 right ventricular (RV) casts were scanned by MSCT. A series of LV and RV short-axis images were reconstructed later with slice thickness of 2.0 mm, 3.5 mm, 5.0 mm, 7.0 mm, and 10.0 mm. Ventricular volume was calculated by the multislice tomographic Simpson's method. True LV and RV cast volumes were determined by water displacement., Results: Both calculated LV and RV volumes correlated highly with the corresponding true volumes (all r >0.95, P <0.01). But with slice thickness from 2.0 mm to 10.0 mm, MSCT scanning overestimated the corresponding true volume by (3.21 +/- 5.95) ml to (12.58 +/- 8.56) ml for LV and (10.22 +/- 8.45) ml to (23.91 +/- 12.24) ml for RV (all P <0.01). There was a very high correlation between the overestimation and the selected slice thickness for both LV and RV volume measurements (r=0.998 and 0.996, P <0.01, respectively). However, when slice thickness was reduced to 5.0 mm, the overestimation for both LV and RV volume measurements became nonsignificant for slice thickness from 2.0 mm to 5.0 mm., Conclusions: Both LV and RV volumes can be accurately estimated by MSCT. Thinner slice has more accurate calculated volume. However, 5.0 mm slice thickness is thin enough for an accurate measurement of LV or RV volume.

Objective: To determine the usefulness of vectorcardiography (VCG) in assessing myocardial infarct size., Methods: The correlation of spatial and scalar parameters of VCG with the percent defect volume (%DV) of thallium myocardial single photon emission computed tomography (SPECT) was investigated in 63 patients with first-onset myocardial infarction (MI). VCG parameters included: (1) spatial parameters: magnitude, azimuth and elevation of the maximal vector, vectors at 20 ms and 30 ms, and (2) scalar parameters: amplitudes of 20 ms and 30 ms vectors at X, Y, and Z scalar leads abbreviated as X20, Y20, Z20, X30, Y30 and Z30, respectively., Results: For anteroseptal MI, the azimuth of 30 ms vector and Z20 showed a significant correlation with %DV (r = 0.572, P < 0.05 and r = 0.832, P < 0.001) while in anteroseptal MI with involvement of lateral wall, the azimuth of 30 ms vector and X30 were correlated with %DV significantly (r = 0.775, and r = 0.780, P < 0.01). For inferior and inferoposterior MI, the elevation of 30 ms vector and Y30 were correlated well with %DV (r = 0.871, P < 0.01, r = 0.928, P < 0.001 for inferior MI and r = 0.678, P < 0.01, r = 0.760, P < 0.001 for inferoposterior MI)., Conclusion: VCG parameters, especially scalar parameters, can be used to evaluate myocardial infarct size easily and non-invasively with remarkable accuracy.