Correlation of adenosine thallium 201 perfusion patterns with markers for inducible ischemia

Practical instructions for using drugs in CT and MR cardiac imaging

The progressive increase in numbers of noninvasive cardiac imaging examinations broadens the spectrum of knowledge radiologists are expected to acquire in the management of drugs during CT coronary angiography (CTCA) and cardiac MR (CMR) to improve image quality for optimal visualization and assessment of the coronary arteries and adequate MR functional analysis. Aim of this review is to provide an overview on different class of drugs (nitrate, beta-blockers, ivabradine, anxiolytic, adenosine, dobutamine, atropine, dipyridamole and regadenoson) that can be used in CTCA and CMR, illustrating their main indications, contraindications, efficacy, mechanism of action, metabolism, safety, side effects or complications, and providing advices in their use.

Cardiac drugs used in cross-sectional cardiac imaging: what the radiologist needs to know

The demand for cross-sectional imaging of the heart is increasing dramatically and in many centres these imaging techniques are being performed by radiologists. Although radiologists are familiar with the computed tomography (CT) and magnetic resonance imaging (MRI) techniques to generate high-quality images and with using contrast agents, many are less familiar with administering the drugs necessary to perform CT coronary angiography and cardiac MR reliably. The aim of this article is to give an overview of the indications for and the contraindications to administering cardiac drugs in cross-sectional imaging departments. We also outline the complications that may be encountered and provide advice on how to treat these complications when they occur.

Adenosine a2A analogue reduces long-term neurologic injury after blunt spinal trauma1,2

BACKGROUND

ATL-146e is an adenosine A(2A) agonist that has recently been demonstrated to improve neurological outcome in spinal cord injury in animals. In the current study, we extended the treatment paradigm and tested neurobehavioral functioning out to 1 week after injury to assess if early neurological improvement is sustained long term by an adenosine analogue.

MATERIALS AND METHODS

New Zealand White rabbits (3.0-3.5 kg) sustained mid-thoracic blunt spinal cord injury using a weight-drop model (10 g weight dropped from 6 cm directly onto dura). Animals received either (1) 3 h iv infusion of saline carrier (Trauma, N = 21); (2) 3 h iv infusion of 0.06 microg/kg/min ATL-146e followed by intraperitoneal bolus of 10.8 microg/kg ATL-146e at 3 h postinjury (ATL, N = 14); or (3) 3 h iv infusion of 0.06 microg/kg/min ATL-146e followed by intraperitoneal bolus injection of 10.8 microg/kg ATL-146e at 3, 12, and 24 h postinjury (ATL-PLUS, N = 11). Fourteen animals underwent sham injury. Hemodynamic parameters were monitored and hind limb motor functioning was assessed by Tarlov scores (0 = paralyzed to 5 = normal hop) for 7 days after injury.

RESULTS

ATL-146e significantly improved Tarlov scores of ATL-146e groups compared with saline-treated controls (P < 0.01 12, 24, 36, and 48 h). Control animals, severely neurologically impaired at 48 h (Tarlov 1.61 +/- 0.35), were euthanized early due to ethical concerns, thus not permitting later statistical comparisons. Early neurological improvements in both ATL-146e-treated groups were sustained longer term (7 day mean Tarlov, SHAM 4.9 +/- 0.30, ATL 5.0 +/- 0, ATL-PLUS 4.25 +/- 0.31).

CONCLUSIONS

ATL-146e given immediately after blunt spinal cord trauma significantly improves neurological outcome, which is sustained through 7 days. Early adenosine A2A receptor agonism may be critical since additional IP administration afforded no further neurological improvement. The current data further support the potential clinical utility of adenosine A(2A) agonists in the treatment of spinal cord injury.

Myocardial infarction during adenosine stress test

A 65 year old woman with history of ischaemic heart disease underwent standard adenosine stress test for myocardial perfusion imaging. She sustained inferior myocardial infarction during the final stages of the stress test. She was admitted to the coronary care unit and received thrombolytic treatment. The patient made an uneventful recovery. Adenosine is widely used for myocardial stress imaging tests and has a good safety profile. So far there has been only one other reported myocardial infarction during adenosine stress test, which was under special circumstances because three days before the test the patient had undergone percutaneous transluminal coronary angioplasty when a severe circumferential dissection was noted. The present patient's case highlights the need to be aware of rare but potentially serious complications of adenosine, even though it generally has an excellent safety record for use in myocardial stress testing.

Accuracy of left ventricular ejection fraction determined by gated myocardial perfusion SPECT with Tl-201 and Tc-99m sestamibi: comparison with first-pass radionuclide angiography

BACKGROUND

We compared estimates of left ventricular ejection fraction (LVEF) assessed by gated single photon emission computed tomography (SPECT), using both technetium-99m sestamibi and thallium-201, with those obtained by first-pass radionuclide angiography (FPRNA) in patients with a broad spectrum of LVEF and perfusion abnormalities.

METHODS

Sixty-three patients were randomly selected to undergo a dual isotope gated SPECT study (rest Tl-201 followed by adenosine Tc-99m sestamibi scintigraphy). Studies were processed by use of the Cedars quantitative gated SPECT software. FPRNA was acquired during an intravenous bolus injection of Tc-99m sestamibi and processed with a commercially available software.

RESULTS

The estimates of LVEF were similar (P = NS) with Tl-201 gated SPECT (54% +/- 15%), Tc-99m gated SPECT (54% +/- 16%), and FPRNA (54% +/- 12%). There was an excellent correlation between Tc-99m and Tl-201 gated SPECT (Pearson's r = 0.92, P < .0001). There were also good linear correlations between Tc-99m sestamibi gated SPECT and FPRNA (Pearson's r = 0.85, P < .0001), as well as between Tl-201 gated SPECT and FPRNA (Pearson's r = 0.84, P < .0001). In the 16 patients with LVEF < 50%, Tc-99m sestamibi gated SPECT and FPRNA (Pearson's r = 0.84, P < .0001) and Tl-201 gated SPECT and FPRNA (Pearson's r = 0.92, P < .0001) correlated well.

CONCLUSION

LVEF can be accurately assessed by gated SPECT with either Tc-99m sestamibi or Tl-201 in properly selected patients with normal or depressed left ventricular function.