Abstract
Ventilation/perfusion scintigraphy, a first hand method for diagnosis of pulmonary embolism, PE, is challenged by tomography of the pulmonary arteries, CT. An additional method is based upon dead space analysis. Tomographic ventilation/perfusion scintigraphy, V/PSPECT is superior to planar technique. Important is interpretation criteria based upon pattern recognition and clinical information. With optimal strategy, the rate of non-diagnostic findings is only about 1%. The sensitivity of CT is too low to exclude subsegmental PE,. The radiation dose is for CT is several times higher than for V/PSPECT. Quantification of PE, only offered by V/PSPECT has impact on therapy and is vital for follow up. Limited availability of V/PSPECT makes CT an essential element in a strategy for diagnosis of PE. The single breath test for CO2 offers an alternative when imaging techniques are not available or when radiation is a particular problem in early pregnancy.