Contrast column interruption artefact in computed tomography pulmonary angiography.

Area of Science:

• Radiology
• Medical Imaging
• Cardiovascular Imaging

Background:

• Computed tomography (CT) pulmonary angiography is a key diagnostic tool for pulmonary embolism.
• Multidetector row CT scanners have increased the frequency of CT pulmonary angiography examinations.
• Artifacts can compromise the diagnostic quality of CT pulmonary angiograms.

Observation:

• Inspiratory maneuvers during CT pulmonary angiography can lead to interruption of the contrast medium column within the pulmonary arteries.
• This interruption presents as a non-opacified segment, mimicking or obscuring intraluminal filling defects.
• The artifact is particularly noticeable when rapid injection protocols are used or patient cooperation is suboptimal.

Findings:

• The primary cause of contrast column interruption during inspiration is the complex interplay between respiratory mechanics and contrast dynamics.
• During inspiration, negative intrathoracic pressure can draw unopacified blood from the superior vena cava into the right atrium and ventricle, diluting the injected contrast.
• This dilution effect, combined with the timing of contrast arrival in the pulmonary arteries, results in the observed artifact.

Implications:

• Non-diagnostic CT pulmonary angiograms necessitate repeat examinations, increasing patient radiation exposure and healthcare costs.
• Understanding the etiology of inspiratory contrast interruption is crucial for optimizing CT pulmonary angiography protocols.
• Implementing breath-hold instructions and tailored injection protocols can mitigate this artifact, improving diagnostic accuracy for pulmonary embolism detection.