Chronic pulmonary emboli
Chronic pulmonary emboli are mainly a consequence of incomplete resolution of pulmonary thromboembolism.
- vascular CT signs include
- direct pulmonary artery signs
- signs related to pulmonary hypertension
- signs of systemic collateral supply
- enlargement of bronchial and non-bronchial systemic arteries
- parenchymal signs (often non-specific on their own):
Nuclear medicine: V/Q scan
Some publications suggest that V/Q scanning may be more sensitive but less specificthan CTPA in detecting chronic pulmonary embolic burden.
Increased vascular resistance due to obstruction of the vascular bed leads to pulmonary hypertension.
Differential considerations on a CTPA include :
- perivascular pulmonary edema
- artefacts/interpretational errors
- motion: breathing artefact
- flow-related artefact
- streak artefact
- due to incorrect window settings
- misinterpretation of veins as arteries
- pulmonary arterial catheter
- intrinsic intraluminal tumor