[Estimation of cardiac output from dynamic contrast multispiral tomographic data].
OBJECTIVE
To describe and apply a method for programmatically calculating central hemodynamic parameters from the data of dynamic contrast X-ray computed tomography (CT).


METHODS
A procedure is proposed to calculate cardiac output (CO) on the basis of the tracer dilution method as a ratio of the injected dose of a contrast agent (Urografin, Shering AG, Austria) to the area under the concentration-time curve derived for one of the cardiac chambers: [see text]. The blood concentration of the agent was estimated from the blood iodine (I) concentration-X-ray density (XD) regression dependence: [XD] = 0.49+22.07 x [I]. Thirty-three patients were studied on a multispiral X-ray Somatom Sensation 4 computed tomograph (Siemens), by injecting 15-20 ml of Urografin. The calculating method was realized as a software package for processing dynamic contrast CT data.


RESULTS
The proposed method could exactly determine the values of cardiac output: the correlation with the results of the reference technique (Doppler echo measurement) was highly significant (r = 0.95; p < 0.001) in the whole range of values. Moreover, the data on XD could accurately determine the blood concentration of both iodine (I): [XD] = 0.49+22.07 x [I] and gadolinium as a component of the contrast paramagnetic Gd-DTPA for which the solution concentration-XR dependence was as follows: XD 1.2+33.6 x [Gd].


CONCLUSIONS
Thus, dynamic spiral CT may be also used for the estimation of cardiac output by the tracer dilution method.
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D000293:Adolescent; D000328:Adult; D000368:Aged; D002302:Cardiac Output / Q000502:physiology*; D002675:Child, Preschool; D003287:Contrast Media; D003974:Diatrizoate Meglumine / Q000627:therapeutic use; D005260:Female; D019786:Gadolinium DTPA / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008875:Middle Aged; D036542:Tomography, Spiral Computed / Q000295:instrumentation*
D003287:Contrast Media; D003974:Diatrizoate Meglumine; D019786:Gadolinium DTPA