Measurement of Pulmonary Arteries in Pulmonary Hypertension


Figure 1A. Pulmonary Hypertension on the Frontal Chest Radiograph

Enlargement of the central right pulmonary artery is present if the transverse diameter of the right interlobar pulmonary artery (bar) exceeds 15 mm in women and 16 mm in men.


Figure 1B. Pulmonary Hypertension on the Lateral Chest Radiograph

The central left pulmonary artery can be measured on the lateral radiograph from the orifice of the left upper lobe bronchus to the posterior aspect of the vessel (bar).

Enlargement of the right ventricular outflow tract is indicated by filling of the inferior aspect of the retrosternal clear space.

Find the right pulmonary artery.


Figure 2A. MR in Pulmonary Hypertension

T1-weighted axial MRI shows enlarged diameter of the main pulmonary artery segment (white line).

Note that the main pulmonary artery segment is larger than the diameter of the ascending aorta at the same level, indicating abnormal pulmonary arterial enlargement.

Ao = Ascending aorta

PA = Main pulmonary artery




Figure 2B. MRA in Pulmonary Hypertension

MRA (magnetic resonance angiography with gadolinium) confirms the enlargement of the pulmonary artery segment. Compare the diameter of the adjacent ascending aorta (to the left of the black line) with the length of the black line.


Figure 2C. T1-Weighted Axial MR

The heart shows marked right ventricular hypertrophy. See asterisks.

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Right pulmonary artery