Quantifying pulmonary perfusion in primary pulmonary hypertension using electron-beam computed tomography.
Traditionally, a gravitational distribution of pulmonary perfusion has been described in normal subjects. How this may vary in patients with primary pulmonary hypertension (PPH), which is characterised by vascular obstruction due to intimal thickening, smooth muscle cell proliferation and episodes of thrombosis in small and medium sized pulmonary arteries, is unclear. In this study the potential of electron-beam computed tomography in quantifying the distribution of pulmonary perfusion in patients with PPH was investigated. Contrast-enhanced sections were obtained during inspiration in the supine position at baseline and during administration of the vasodilator adenosine in five healthy subjects and five patients with PPH. Under each experimental condition, regions of interest were placed along the nondependent-to-dependent axis and values for relative perfusion derived. In healthy individuals, a marked nondependent-to-dependent gradient in perfusion was observed. By contrast, in PPH, perfusion values were significantly lower and were uniform across the lung section, although the administration of adenosine resulted in increased perfusion in all regions of interest. Electron-beam computed tomography provides physiological and structural information about the pulmonary circulation in subjects with pulmonary vascular disease.
Unit of Critical Care, National Heart and Lung Institute, Imperial College of Science, Technology and Medicine, Royal Brompton Hospital, London, UK.
A T
AT
Jones
D M
DM
Hansell
T W
TW
Evans
D000241:Adenosine / Q000008:administration & dosage; D000328:Adult; D001783:Blood Flow Velocity / Q000187:drug effects / Q000502:physiology; D003287:Contrast Media / Q000008:administration & dosage; D004305:Dose-Response Relationship, Drug; D005260:Female; D006439:Hemodynamics / Q000187:drug effects / Q000502:physiology; D006801:Humans; D006976:Hypertension, Pulmonary / Q000000981:diagnostic imaging* / Q000188:drug therapy; D007091:Image Processing, Computer-Assisted; D007472:Iohexol; D008168:Lung / Q000098:blood supply*; D008297:Male; D008432:Mathematical Computing; D008875:Middle Aged; D011651:Pulmonary Artery / Q000000981:diagnostic imaging / Q000187:drug effects; D012016:Reference Values; D012039:Regional Blood Flow / Q000187:drug effects / Q000502:physiology; D014057:Tomography, X-Ray Computed; D014655:Vascular Resistance / Q000187:drug effects / Q000502:physiology; D014665:Vasodilator Agents / Q000008:administration & dosage
D003287:Contrast Media; D014665:Vasodilator Agents; D007472:Iohexol; D000241:Adenosine