The quantitative measurement of right ventricular (RV) turn has been attempted by a number of courses including nuclear magnetic resonance imaging.

The quantitative measurement of right ventricular (RV) turn has been attempted by a number of courses including nuclear magnetic resonance imaging, contrast angiography, echocardiography, and radionuclide angiography. All of these arrangements have limitations. Ultrafast cine comput tomographic (CT) scan is a strange technology that may have an important part in on-line ventricular volume measurements. Twelve human explanted hearts, fixed in formalin, were make subordinateed to ultrafast cine CT scans to estimate RV turn The volumes derived from the CT scans were compared with actual fluid tomes needed to fill the RV contortion measurements. All measurements were escorted independently by two observers. Actual RV bodys in the 12 hearts ranged from 298 ml to 1746 ml A violently significant correlation between actual dimensions and CT volume was seen (r = 099) Agreement between regarders was also seen to be highly significant (r = 0992) Limitations to accurate in vivo assessment to be paid to bolus injection of contrast medium might include alterations in ventricular crushing change. Similarly, differentiation of the endocardial border with contrast may not be as sharp as that with an air-tissue interface. This application of mind demonstrates that RV volumes can be reliably determined on ultrafast cine CT scans in explanted hearts. On-line systolic and diastolic whirls and thus stroke volume, ejection fraction, etc can be accurately defined independent of cardiac orientation. This technique moves opportunities to study ventricular function below various conditions.

Right ventricular (RV) dysfunction is being increasingly recognized as a major composing in a spectrum of cardiopulmonary disorders.[1] Quantitative measurement of RV body is difficult to obtain because of pleomorphic nature of the RV[2] The generally available methods for quantitative assessment of RV function include contrast ventriculography,[3] radionuclide angiography,[4] echocardiography,[5] and nuclear magnetic resonance imaging.[6] However, all the above-mentioned orders have inherent limitations.

The emerging recent technology, ultrafast cine computed tomography (ultrafast cine CT) provides an estimable avenue to assess the cardiac morphology.[7] Ultrafast cine CT has been shown to yield accurate measurements of left ventricular mass and left ventricular ejection fraction without the necessity of assuming an idealized mathematical standard for the shape of the left ventricle.[8] In a newly come study, Mahoney and coworkers[9] compared RV dimensions of excised fixed canine hearts with ultrafast CT and institute accurate measurements (r = 096) when compared with actual RV compass as measured by cavity fluid capacity. This consideration is designed to compare fixed human explanted hearts following orthotopic human transplantation against ultrafast CT derived RV volume

MATERIAL AND METHODS

Cardiac Tissue Preparation

The experimental preparation for these studies comprised 12 explanted human hearts. Each heart was excised and rinsed at liberty of blood and clots. The great ducts and atria were removed, leaving the ventricles intact as well as the tissue constituting the atrioventricular and semilunar valve annuli. The RV cavities were packed with gauze to maintain cavity shape and the hearts were fixed in 10 percent duffered formalin for at least 48 h; after formalin fixation, the gauze packing was removed

Cine Comput Tomography Scanning

Tomography was performed with a CT order (Imatron C-100 cine CT system) This method consists of an electron-beam cine CT scanning device used to obtain 3-mm-thick tomographic slices. Forty slice scans were acquired in this study

The formalin-fixed human ventricles were placed in the cine CT scanning gantry and oriented with equal reason that the long axis of the right ventricle was approximately perpendicular to the scanning plane. All hearts were scanned in air, using the worthy of great praise contrast of the air-tissue interface. Forty sequential, 3-mm-thick transverse (short-axis) scans were obtained from base to apex at 3-mm intervals produc by the agency of gantry motion. A 26-cm reconstruction circle with a re-established display matrix of 512 x 512 pixels was used for all hearts. Each heart was scanned twice to estimate any reproducibility errors.

Image Analysis

The images were displayed and analyzed (Imatron Console) with supplied software. Based forward examination of the average CT numbers of air in the right and left ventricular cavities and outside the heart, as well as the CT number of myocardium, the on a level was set to -- 450 and window was stake to 1,100.

The RV endocardial contours were identified by way of means of a computer-assisted proces reported previously.[10] Briefly, this image thresholding conduct highlights pixels with values approximately halfway between the CT number values of the myocardium and cavity. Pixels with gray horizontals in this range were displayed as white. This approach to endocardial and epicardial definition was shown to be accurate and reproducible (Fig. 1)[10] The RV cavity areas were then measured and RV whirl was calculated by a Simpson's mastery approximation (using the calculated RV cavity areas from each image and the known interimage distances). The average of the sum of two units scans was used for comparison to conformable to fact RV volume.

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