Table 2.

Differential diagnosis table for posttraumatic pulmonary artery pseudoaneurysm.

	CT	T1/T2-MRI
Hematoma	Mass with increased density extravascular (depending on age of the hematoma).	Perivascular mass with complex T1/T2 signal depending on the chronicity of the thrombus. No contrast flow would be seen in the mass.
True Aneurysm	Bulbous or fusiform abnormal dilatation of the aorta/artery. Contains all 3 layers of the vessel wall. Abnormally dilated artery with no evidence of contrast extravasation.	Abnormally dilated artery with no evidence of contrast extravasation. The true lumen is opacified with contrast.
Vascular malformation	Contrast CT scan shows enhancement of the feeding artery, the aneurysmal part, and the draining vein on early-phase sequences.	Rapidly flowing blood results in absent or minimal MR sign. Regions of slow blood flow may result in intermediate signal intensity
Tumor and/or metastases	Depending on the origin of the tumor imaging can vary between high density or low density. Sometime vessels are connecting with the lesion.	Size <5 mm pulmonary nodule can hardly be detected in MRI.
Pseudoaneurysm	Early arterial contrast enhancement without venous pooling in the late phase. Contrast filled pouching with persistent communication to the damaged artery.	Abnormally dilated artery. The true lumen is opacified with contrast.