One stop cardiac investigation ‘CT or echocardiography’: beyond ejection fraction

Abstract

The principle aim of diagnostic cardiovascular imaging is to provide clinically relevant information regarding cardiac anatomy and function. This may be broadly categorised into coronary vascular anatomy, plaque architecture, myocardial perfusion, cavity volume, valvular pathology, and haemodynamics. Each of the major cardiac imaging techniques (chest X-ray, coronary angiography, cardiac MRI, multislice CT, SPECT, FDG-PET, echocardiography) provides a subset of this information to varying degrees according to strengths and weaknesses of the particular modality. The techniques may be compared by invasiveness, spatial resolution, temporal resolution, radiation dose, cost, repeatability, and availability.In this issue of IJCI Bansal et al. report their study comparing 16-slice multi-detector computed tomography (16CT) with conventional 2-dimensional echocardiography for assessment of left ventricular function by cavity volumes and ejection fraction. Their study population consisted of 52 patients with suspected coronary artery disease (CAD) who were referred for routine cardiological investigation. The computed tomography scans were acquired using a 16-slice scanner with contrast enhancement but without dose modulation. Echocardiographic assessment of cavity volumes and ejection fraction were calculated from Simpson's and biplane Simpson's planimetry. Their results showed significant correlation between the two modalities for biplane cavity volume measurements (LVESV r = 0.69; LVEDV r = 0.73; P \ 0.01) with echocardiography consistently underestimating cavity volume, but very close agreement for ejection fraction (CT EF = 59.7 ± 12% vs. Echo EF = 58 ± 13%, r = 0.59; P \ 0.01). Previous studies [1, 2] have reported similar results to that by Bansal et al. and there is evidence for consistent over-or under-estimation with multidetector CT and echocardiography, respectively, compared with cardiac MRI.Technical limitations as well as the immutable laws of physics govern the strengths and weaknesses of the major cardiac imaging techniques. Cardiac MRI is accepted as the 'gold standard' measurement for ventricular cavity volume, and therefore ejection fraction, by calculation. Cardiac MRI is also known for its excellent tissue delineation, useful when assessing infarcted myocardium or fibrosis. These Editorial comment on the article by Bansal et al. in the current issue of this journal.

Characterization of mitral valve prolapse with cardiac computed tomography: comparison to echocardiographic and intraoperative findings

“…It is not surprising that our study results suggest that CT has suboptimal operating characteristics and had difficulty identifying prolapsing scallops, as current CT imaging has inferior temporal resolution than echocardiography (15-60 ms) [19].…”

Left ventricular systolic function in subjects conceived through assisted reproductive technologies

“…The use of RT3DE might have revealed more subtle alterations as it provides very accurate and reproducible measurements of LV volumes and EF (46). As cardiac magnetic resonance imaging is considered to be the gold-standard for the determination of LV volumetric and functional indices, it should be implemented in future study designs (47).…”

Cardiac multi-detector CT: Its unique contribution to cardiology practice

“…A limited number of studies have provided promising comparative data with MRI and ventriculography, leading their authors to suggest a potential use of MDCT as a one stop non-invasive cardiac investigation for coronary arteries as well as ventricular function [39][40][41]. However, this proposal has limitations since cardiac physiology, filling pressures and valve disease can only be assessed in detail by Doppler echocardiography because of its unique acquisition features [42].…”