SUMMARY Arterial compliance was measured in 70 healthy volunteers, 13 athletes, and 17 patients with coronary artery disease. Magnetic resonance images were acquired at end diastole and end systole through the ascending aorta, the aortic arch, and the descending thoracic aorta. Regional compliance was derived from the change in luminal area in a slice of known thickness and from the pulse pressure. Total arterial compliance was also measured from the left ventricular stroke volume and the pulse pressure. In the volunteers, mean (SD) regional compliance (Ml/mm Hg) was greatest in the ascending aorta (37 (18)), lower in the arch (31 (15)), and lowest in the descending aorta (18 (8)), and it decreased with age. Compliance in the athletes was significantly higher than in their age matched controls (41 (16) versus 22 (11) 1l/mm Hg). In the patients with coronary artery disease it was significantly lower (12 (4) v 18 (10)) than in age matched controls. Total arterial compliance also fell with age in those with coronary artery disease although there was more variation.The results suggest a possible role for compliance in the assessment of cardiovascular fitness and the detection of coronary artery disease.A popular saying is that a man is as old as his arteries. The commonest arterial disease is "hardening of the arteries" or atherosclerosis which leads, among other things, to a loss of elasticity. Arterial elasticity is measured as compliance, which is the change in volume per unit change in pressure, and compliance measurements may be valuable for both detection and monitoring of disease.Magnetic resonance imaging is a direct noninvasive way of studying regional aortic compliance and total arterial compliance. We used it to study changes in compliance with age and aortic compliance in athletes and in patients with coronary artery disease. Patients and methodsWe studied 70 Accepted for publication 7 March 1989 13 athletes (mean age 43, range 29-56), and 17 patients with coronary artery disease without previous infarction (mean age 53, range 30-76). Three of the athletes were of international standard (one Olympic gold medal) and the others were club athletes. The average distance run daily was nine miles.We used a Picker International Vista MR2055 machine operating at 0-5 T to acquire images at end diastole and end systole in three oblique planes perpendicular to the midpoints of the ascending aorta, the aortic arch, and the descending thoracic aorta (fig 1). A spin echo sequence (TE 40 ms) was used with two averages of 128 phase encoding steps, a pixel size of 1417 mm x 1-17 mm, and a slice thickness of 10 mm. The end diastolic images were acquired 100 ms before the average RR interval, and the end systolic images at the end ofthe T wave ofthe electrocardiogram Acquisition time was three to four minutes per image depending upon heart rate.The lumen of the aorta was outlined manually on the computer screen, and regional aortic compliance was calculated from the change in volume between diastole and systole. The p...

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SUMMARY Magnetic resonance velocity mapping by the field even echo rephasing sequence was used to provide two dimensional velocity profiles in the ascending and the descending aorta. Flow patterns were studied in ten healthy volunteers by a display method that gave clear details of the profiles. Velocity profiles in the ascending aorta were skewed in systole with an axis of skew roughly symmetrical about the plane of the aortic arch. During diastole flow was reversed along the posterior left wall of the ascending aorta while it continued forwards at the anterior right wall. In the descending aorta plug flow occurred but with minimal skew. Flow along the right wall was reversed during diastole. Turbulent flow did not occur in the ascending or descending aorta of any healthy subject.Magnetic resonance velocity mapping is a very powerful tool for the study of cardiovascular physiology. Its non-invasiveness, its quantitative two-dimensional data, its accuracy, and its high spatial resolution make it suitable for clinical use.The complex phenomena of blood flow in the heart and blood vessels are worthy of study because they give an insight into the normal and pathological function of the cardiovascular system. Flow profiles are known to be modified in some diseases1 2