Investigative radiology
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Investigative radiology · May 1982
Comparative StudyPulmonary blood volume: correlation of equilibrium radionuclide and dye-dilution estimates.
In fifteen prospective patients with aortic stenosis undergoing transseptal cardiac catheterization, dye-dilution and count-based estimates of pulmonary blood volume (PBV) were performed. Three radionuclide methods were evaluated. Two were based on electrocardiogram (ECG)-gated imaging of the thorax, where pulmonary counts (PC) were corrected for frame-time, venous radioactivity, and either (1) the number of processed heart beats or (2) the total duration of acquisition. ⋯ In five acutely instrumented, anesthetized dogs, radionuclide (ungated formula) and dye-dilution estimates of PBV were made during multiple interventions (19 data points). The five control count volumes as well as the 14 separate intervention points correlated well (r greater than 0.89). It is concluded that PC from equilibrium blood pool images reflect PBV and that induced changes in PC can be utilized as a reflection of changes in PBV.
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Investigative radiology · May 1982
Effects of low osmolality contrast materials on coronary hemodynamics, myocardial function, and coronary sinus osmolality in normal and ischemic states.
The effects of intracoronary administration of contrast materials on regional and global left ventricular (LV) function and coronary sinus osmolality were assessed in six anesthetized dogs with segmental myocardial ischemia produced by critical stenosis of the circumflex coronary artery. Effects caused by Renografin (sodium meglumine diatrizoate), two new low osmolality contrast agents (Hexabrix and Hexabrix with added calcium ions), and metrizamide were evaluated. In a nonischemic state, Renografin produced an early (0-10 seconds) decrease in LV contractility followed by a late (10-20 seconds) rebound augmentation in contractility. ⋯ This lack of depressant effects was also observed in the ischemic state. Renografin caused a significantly greater increase in coronary sinus osmolality (Tp) as compared with Hexabrix, Hexabrix-Ca++, and metrizamide. The increases in osmolality in response to the latter three contrast agents were statistically indistinguishable.