Analysis of decrease in lung perfusion blood volume with occlusive and non-occlusive pulmonary embolisms

Volumetric capnography in the exclusion of pulmonary embolism at the emergency department: a pilot study

“…Due to the exclusion criteria, only patients with low and moderate risk PE were included, which is reflected in the low PESI scores. Furthermore, it has been shown that in non-occluding emboli pulmonary blood flow is preserved [20]. Even if total occluding emboli are present, ventilation may shift to better perfused regions due to hypocapnic bronchoconstriction [21].…”

The TL,NO/TL,CO ratio cannot be used to exclude pulmonary embolism

“…First of all, a probable cause of the lack in increased T L,NO /T L,CO ratios might be the relatively small extent of the pulmonary emboli included in the current study, as hemodynamic unstable and oxygen-dependent patients were excluded. Moreover, recent research showed that total occluding emboli result in perfusion defects (Ikeda et al, 2014), and in nonoccluding emboli, a slight decrease in both D m and V C can be expected. Finally, hypocapnic bronchoconstriction might shift ventilation towards well-perfused regions (Tsang et al, 2009) which could also diminish the negative effects of PE on the diffusion capacity of the lungs.…”

Dual-Energy CT for Pulmonary Embolism: Current and Evolving Clinical Applications

“…However, an iodine map must be interpreted with caution because iodine maps selectively demonstrate iodinated contrast material within the lung parenchyma, not true perfusion [32]. In addition, PE does not always cause perfusion defects in an iodine map [20,25,34,79]. Although the rate of perfusion defects on PBV for occlusive PE is relatively high (82-95%), the rate of perfusion of non-occlusive PE defects may be as low as 6-9% [20,25,34], and other lung diseases can also cause perfusion defects [80].…”