Michael Schafers

Geschlechtsspezifische Unterschiede in der absoluten myokardialen Perfusion

AIM To investigate sex differences in myocardial perfusion especially in healthy individuals since former studies are rare and findings are controversial. Participants, methods: 26 subjects were enrolled: 16 healthy women (age: 34 ±7 years) were compared with 10 healthy men (age: 34 ± 3 years; p = ns). Myocardial blood flow (MBF) and coronary vascular resistance (CVR) were quantified at rest, during adenosine infusion and cold-pressor-testing, using positron emission tomography and radioactive-labelled water (H2(15)O-PET). RESULTS Women showed higher MBF than men at rest (1.10 ± 0.18 vs. 0.85 ± 0.20 ml/min/ml; p = 0.003) and cold-stress (1.39 ± 0.38 vs. 1.06 ± 0.28 ml/min/ml; p = 0.026). Corrected for rate-pressure-product, baseline findings maintained significance (1.41 ± 0.33 vs. 1.16 ± 0.19 ml/min/ml; p = 0.024). CVR was lower in women at baseline (81 ± 14 vs. 107 ± 22 mmHg*ml(-1)*min*ml; p = 0.006) and during cold-pressor-testing (71 ± 17 vs. 91 ± 20 mmHg*ml(-1)*min*ml; p = 0.013). Under adenosine neither maximal MBF (4.06 ± 1.0 vs. 3.91 ± 0.88 ml/min/ml; p = ns) nor coronary flow reserve (3.07 ± 1.12 vs. 3.44 ± 0.92; p = ns) nor CVR (24 ± 8 vs. 24 ± 6 mmHg*ml(-1)*min*ml; p = ns) showed sex-related differences. CONCLUSION Women show higher myocardial perfusion and lower coronary vascular resistance than men in physiologic states. Maximum perfusion and vasodilation under adenosine are not sex-specific.

Imaging in Cardiovascular Research

Despite enormous investment into cardiovascular research on all levels worldwide, cardiovascular events such as myocardial infarction, heart failure, tachyarrhythmia or stroke remain the major causes for death and inability in all developed countries. Conventional clinical cardiovascular imaging nowadays provides high-resolution visualization of the morphology of vessels and the myocardium. To translate the available patient imaging technologies into animals, especially mice where genetic technologies can be used to induce human-like pathophysiologies, is of great interest for cardiovascular research. Furthermore, new imaging biomarkers for targeting molecular processes such as inflammation in atherosclerosis are being developed which have to be tested and optimised in animal models (again mice are of greatest interest here) before translated into the clinics. Imaging of the heart and the vessels of a mouse poses significant challenges for small animal imaging systems with respect to the spatial and temporal resolution. This chapter elucidates the relevant cardiovascular pathologies and clinical challenges, reviews animal models of cardiovascular disease and shows examples of applications of small animal imaging by CT, ultrasound, MRI, SPECT, PET and optical imaging.