Myocardial perfusion assessment at rest and after dipyridamole: MR signal intensity characteristics of reversible and persistent hypoperfusion

Aim: Performance of combined rest/stress MR perfusion studies and the analy sis of qualitative signal intensity parameters in comparison with Tc-99m-Se staMIBI SPECT in patients with known coronary artery disease (CAD). Methods: Sixteen patients with CAD underwent MR myocardial perfusion assess ment at rest and after dipyridamole-induced hyperemia. Qualitative paramete rs (SI increase, SI upslope) of the SI time-curves were evaluated and chara cteristics of normal, reversible and persistent hypoperfused myocardium as assessed by 99mTc-SestaMIBI SPECT were compared. Results: Compared with the rest values, normal myocardium showed a signific ant increase of the SI upslope during hyperemia (P<0.001), whereas persiste nt (P=0.07) and reversible (P=0.15) hypoperfusions showed only minor change s. Si increase over baseline also showed a significant increase only in nor mal myocardium (P<0.001). At rest, reversible ischemic areas showed no sign ificant differences from normal myocardium, whereas during hyperemia SI inc rease was significantly lower (P=0.02). Conclusions: Qualitative SI parameters of a combined rest/stress MR myocard ial perfusion study allow to differentiate normal from reversibly or persis tently hypoperfused myocardium.