Magnetic resonance imaging demonstration of pharmacologic-induced myocardial vasodilatation using a macromolecular gadolinium contrast agent.

Rationale And Objectives: Adenosine is a potent vasodilator used clinically in nuclear scintigraphy to assess coronary artery reserves. The potential to identify this vasodilating effect of adenosine using magnetic resonance imaging (MRI), which is superior in spatial resolution to nuclear scintigraphy, combined with a blood-pool MRI contrast agent, was investigated in normal rats.

Methods: Groups of Sprague-Dawley rats received successive infusions of either adenosine (3 mg/kg/minute; n = 7) or dipyridamole (negative control; up to 1.

Hypercarbia-induced changes in cerebral blood volume in the cat: a 1H MRI and intravascular contrast agent study.

Cerebral blood volume changes with arterial carbon dioxide were monitored by proton T1-weighted MR images following administration of the intravascular contrast agent Gd-DTPA labeled with human serum albumin. Without MR contrast, no significant image intensity changes were observed with PaCO2. Following contrast, regional brain image intensities increased significantly over control (0% inspired CO2) in cortical gray, white, and basal ganglia regions with increasing PaCO2 and returned to control intensities upon return to 0% inspired CO2.

Contrast-enhanced magnetic resonance imaging of tumor-bearing mice treated with human recombinant tumor necrosis factor alpha.

Pharmacological effects of recombinant human tumor necrosis factor alpha (TNF) were studied in a mouse fibrosarcoma model using magnetic resonance imaging enhanced with a macromolecular contrast agent, albumin(gadolinium-diethylenetriamine pentaacetic acid)35. TNF was administered i.v.

Assessment of myocardial salvage after ischemia and reperfusion using magnetic resonance imaging and spectroscopy.

To test the hypothesis that contrast-enhanced magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) can differentiate reversible from irreversible myocardial injury, these modalities were used to study ischemia and reperfusion in a rat model. The presence of ischemia and reperfusion were confirmed with radiolabeled microspheres (n = 6). Groups of animals were subjected to either 16 (n = 17), 30 (n = 14), 60 (n = 11), or 90 (n = 14) minutes of left coronary artery (LCA) occlusion and 60 minutes reperfusion.