Purpose: To determine perfusion and coronary reserve in human myocardium without contrast agent using a spin labeling technique. Materials and Methods:Assessment of myocardial perfusion is based on T1 measurements after global and sliceselective spin preparation. This magnetic resonance imaging (MRI) technique was applied to 12 healthy volunteers and 16 patients with suspected coronary artery disease under resting conditions and adenosine-induced vasodilatation. Results:In volunteers, quantitative perfusion was calculated as 2.4 Ϯ 1.2 mL/g/minute (rest) and 3.9 Ϯ 1.3 mL/g/minute (adenosine), respectively. Perfusion reserve was 2.1 Ϯ 0.6. In patients, when comparing perfusion reserve in the anterior and posterior myocardium, reduced values according to a stenotic supplying vessel could be seen in seven of 11 patients who underwent stress testing. In these patients, the relative difference of coronary reserve was 44% Ϯ 18%. Two patients without stenosis of coronary arteries showed no differences in coronary reserve (with a relative change of 2 Ϯ 2%). Conclusion:In patients with single-vessel coronary artery disease, differences in coronary reserve were clearly detectable when comparing anterior and posterior myocardium. The spin labeling method is noninvasive and easily repeatable, and it could therefore become an important tool to study changes in myocardial perfusion.

Included patients benefited subjectively and objectively from the use of rhTSH for diagnostic procedures in the treatment of DTC. A clear preference (127 of 128) of analyzed patients could be identified for exogenous stimulation with rhTSH.

In this study absolute myocardial perfusion was determined using a spin-labeling magnetic resonance imaging (MRI) technique at 2 Tesla. The technique was applied to 16 healthy volunteers at resting conditions, adenosine-induced stress, and oxygen breathing. Overall myocardial quantitative perfusion was determined as 2.3 +/- 0.8 mL/g/min (rest), 4.2 +/- 1.0 mL/g/min (adenosine), and 1.6 +/- 0.6 mL/g/min (oxygen), respectively. T1 of left ventricular blood pool decreased from 1709 +/- 101 ms (rest) to 1423 +/- 61 ms (oxygen), whereas T1 of right ventricular blood did not change significantly (1586 +/- 126 ms and 1558 +/- 150 ms). In conclusion, the presented technique for quantification of myocardial perfusion is an alternative to contrast agent-based methods. The spin labeling method is noninvasive and easily repeatable and it could therefore become an important tool to study changes in myocardial perfusion under different vasodynamic states.

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