Transient interruption of contrast

Case contributed by Sammy Tawk
Diagnosis certain

Presentation

Rule out pulmonary embolism.

Patient Data

Age: 75 years
Gender: Female

Chest CT angiography performed for pulmonary embolism suspicion. The ROI was correctly positioned inside the pulmonary trunk. Inadequate opacification of the pulmonary arteries while the aorta is already well opacified and the SVC/right heart chambers are still opacified.

Case courtesy of Mr. Hussein Harb

Case Discussion

The described phenomenon is known as the transient interruption of contrast of the pulmonary arteries. It results from an increases in non opacified flow contribution from the inferior vena cava (IVC) to the right side of the heart. This can occur when the patient takes a deep breath just before the scanning. This results in decreased intra-thoracic pressure with a subsequent increase in venous inflow, mainly from the IVC.

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