Figure 1b:

Images in a 73-year-old male control subject. Peripheral blood pressure was 130/70 mm Hg (pulse pressure = 60 mm Hg). (a) Longitudinal view of RCA in middiastole. (b) Longitudinal view of RCA in end systole. (c) Transverse view of lumen in middiastole. (d) Transverse view of lumen in end systole. (e) Zoomed view during diastole shows lumen contour (area, 7.61 mm²). (f) Zoomed view during systole shows lumen contour (area, 15.05 mm²). CDI = [(15.05 − 7.61)/(7.61/60)] × 1000 = 16.29 mm Hg⁻¹. Lines in a and b represent locations of transverse views of vessel on its longitudinal view.