The assessment of chronic venous obstructions by non invasive haemodynamic studies and imaging with Kr-81 m venography.

We study the sequelae of venous obstructions (from 15 days to several years after the thrombosis) by non invasive haemodynamic methods: Doppler velocimetry and leg plethysmography. We describe a simple physical model which permits the calculation of the leg outflow resistance from the venous occlusion plethysmography data. A radionuclide imaging of the veins is also recorded by a gammacamera during the perfusion of the limbs with Kr-81 m. This flexible technique appears suitable to analyse persistent ilio-femoro-popliteal obstructions. The results of the Doppler investigation are well related to the phlebograms. The outflow resistance of the leg depends mainly on the duration of the persistent obstruction. Recent obstructions are generally highly resistive but the level of the resistance is becoming close to normal with time (after two years).