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.
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The effects of intracoronary administration of contrast materials were investigated in conscious and anesthetized dogs prepared with pressure gauges or catheters in the left ventricle for measuring aortic pressure (P), LVP, and dP/dt, and dimension crystals on opposing endocardial surfaces of the LV for measuring LV dimensions and its first derivative dD/dt (velocity of contraction). All contrast materials were tested at a concentration of 370 mg I/ml. Biphasic responses were observed with monomeric contrast materials; direct effects occurred within the first 10 seconds after injection, while secondary or indirect effects (reflex?) ensued near the end of the first 10 seconds or in the second 10-second period (Higgins, 1978). ⋯ Several nonionic materials also have been tested in this preparation: metrizamide, P-297, and iopamidol. These materials had similar effects on LV function; each caused a slight increase or no change in indexes of LV contractile state and no change in LV dimensions. A new monacid dimer (P-286) with a lower sodium content than monomeric materials produced effects on LV function which were less deleterious than standard monomeric materials, but more so than the nonionic materials.
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Investigative radiology · Jul 1980
Comparative StudyEffects of ionic and nonionic contrast agents on left ventricular and extracellular fluid dynamics during angiocardiography in an infant model.
Concern for side effects of contrast materials limits the volume that can be used for angiocardiography in infants; many of these effects are related to hyperosmolality. The effects of intracardiac injections of ionic (meglumine sodium diatrizoate) and nonionic (metrizamide) contrast agents on the left ventricle and body fluids were compared in an infant model. Immediately after injection, meglumine sodium diatrizoate (MSD) caused increases in left ventricular peak systolic pressure (LVPSP) (+26 +/- 5%) (control (C) = 92 mmHg), LV dp/dt (+21 +/- 6%) (C = 2610 mmHg/sec), left ventricular end-diastolic dimension (LVEDD) (+31 +/- 5%) (C = 10.5 mm), and left ventricular end-systolic dimension (LVESD) (+28 +/- 6%) (C = 7mm). ⋯ MSD caused greater and more persistent elevations of serum osmolalities than metrizamide. Differences between the two agents were accentuated during systemic hypoxemia. Thus, ionic contrast agents appear to have a greater propensity for inducing toxic cardiovascular effects in infants than nonionic agents.
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Investigative radiology · May 1980
Comparative StudyComparison of iopamidol, ioxaglate, and diatrizoate during coronary arteriography in dogs.
Iopamidol and ioxaglate are two new contrast media which have an osmolality approximately half that of diatrizoate for the same iodine concentration. These three contrast media were compared with each other and with Hartmann's solution during coronary arteriography in dogs using hemodynamic and electrocardiographic parameters in addition to coronary venous sinus sampling to measure changes in osmolality, electrolyte, and contrast media concentration. Iopamidol and ioxaglate had similar, but less toxic, effects in comparison with diatrizoate. These new contrast media may offer a reduction in the morbidity and mortality of coronary arteriography.