Wide lung artery seen by chance on a chest CT

What the report means

How it is measured. The width of the main pulmonary artery is measured on the CT where it splits in two. It is often compared with the width of the aorta next to it, giving a ratio. (Framingham 2012)(Sienkiewicz 2026, citing ESC/ERS 2022)
Why it can widen. The artery widens as it adapts to higher pressure in the lungs. (Framingham 2012) It also gets wider with age and body size, with lung diseases such as emphysema, COPD and lung scarring, with obesity and with left-sided heart disease. (Sienkiewicz 2026, citing ESC/ERS 2022)
Measurement varies. On a low-dose scan, the level and angle of the measurement, breathing and heart movement can push a borderline value across a cut-off. (Sienkiewicz 2026, citing ESC/ERS 2022)
Pulmonary hypertension is uncommon. The NHS describes it as a rare condition that is more common in people with another heart or lung condition. (NHS)

Size cut-offs as cited

Framingham Heart Study. CT scans of 3,171 adults with an average age of 51 found an average width of 25.1 mm. The authors set upper normal values of 29 mm for men, 27 mm for women and 0.9 for the pulmonary artery to aorta ratio. A width above the cut-off was linked to self-reported breathlessness. (Framingham 2012)
2022 ESC/ERS guideline. As cited in a 2026 review, the European pulmonary hypertension guideline lists a width of 30 mm or more and a ratio above 0.9 among CT signs that suggest pulmonary hypertension. (Sienkiewicz 2026, citing ESC/ERS 2022)
Lung screening reports. The same review says the American College of Radiology lung screening guide advises primary care evaluation for a width of 31 mm or more. (Sienkiewicz 2026, citing ESC/ERS 2022)

How often it points to pulmonary hypertension

In people being tested for it. A meta-analysis of 20 studies with 2,134 people found CT width picked up 79% of those with pulmonary hypertension and was normal in 83% of those without it. The authors said results should be read alongside tests such as echocardiography. (Meta-analysis 2014)
In screening scans. The 2026 review reports that 4.2% of 1,949 smokers having a lung screening CT had a width of 34 mm or more, while 23% of another screening group of 777 were above the Framingham cut-offs. (Sienkiewicz 2026, citing ESC/ERS 2022)
In the general population. In Framingham, 7.1% of the whole group had a ratio above 0.9. (Framingham 2012)

When an echocardiogram comes next

Borderline, no symptoms. The 2026 review says an isolated borderline width without other CT signs and without symptoms should be treated as a risk marker rather than a reason for more tests. (Sienkiewicz 2026, citing ESC/ERS 2022)
Other signs or breathlessness. A wide artery with other CT signs, such as an enlarged right side of the heart, or with breathlessness out of proportion to lung tests, should lead to a clinical check followed by an echocardiogram. (Sienkiewicz 2026, citing ESC/ERS 2022)
The main tests. The NHS says the 2 main tests used to diagnose pulmonary hypertension are an echocardiogram, which estimates the pressure in the lung arteries, and right heart catheterisation, done in specialist centres. (NHS diagnosis) The review notes that diagnosis needs pressure measured directly, not a CT. (Sienkiewicz 2026, citing ESC/ERS 2022)

How it ties to your age-based checks

MedlinePlus says the risk of pulmonary hypertension rises with age and lists heart diseases, COPD, emphysema, sleep apnea and blood clots in the lungs among possible causes. (MedlinePlus) In people with COPD, a pulmonary artery wider than the aorta was linked to more severe flare-ups. (Wells 2012) A wide artery is a reason to make sure your routine checks are up to date:

Other chest CT findings have their own pages: wide chest aorta, enlarged heart on a chest X-ray, emphysema found by chance on CT and lung scarring on a chest CT.

Who it applies to

Adults told that a chest CT done for another reason shows a wide main pulmonary artery. Children, people already diagnosed with pulmonary hypertension and people with a known heart condition followed by a specialist are outside this page. The NHS notes that one type of pulmonary hypertension may cause no symptoms until it is quite advanced. (NHS)

NHS, see a GP if you have symptoms of pulmonary hypertension: (NHS)

shortness of breath
tiredness
feeling faint or dizzy
chest pain (angina)
a racing heartbeat (palpitations)
swelling in the legs, ankles, feet or tummy

Call 999 (911 in the US) or go to A&E if you get sudden chest pain that does not stop after a few minutes, or you have heart palpitations with chest pain, shortness of breath or feeling faint. (NHS)

Routine age-based screening

A finding on a chest CT does not replace the routine screenings for your age. See screenings by age and gender.

Where they differ:

The cut-off. Framingham uses 29 mm for men and 27 mm for women; the 2022 ESC/ERS guideline, as cited, uses 30 mm for everyone; the ACR lung screening guide, as cited, uses 31 mm. (Framingham 2012)(Sienkiewicz 2026, citing ESC/ERS 2022)
The ratio. Framingham and the ESC/ERS guideline use 0.9, while the COPD study used a ratio above 1. (Framingham 2012)(Sienkiewicz 2026, citing ESC/ERS 2022)(Wells 2012) Framingham found the normal ratio falls with age, possibly because the aorta widens. (Framingham 2012)
Testing after a borderline result. The NHS lists an echocardiogram as a main test when pulmonary hypertension is suspected. (NHS diagnosis) The 2026 review advises against more tests for an isolated borderline width with no symptoms or other signs. (Sienkiewicz 2026, citing ESC/ERS 2022)

Your doctor decides what your result means for you.

Questions people ask

What size counts as a wide pulmonary artery?

In the Framingham Heart Study the upper normal values were 29 mm for men and 27 mm for women, and 0.9 for the ratio of the pulmonary artery to the aorta. A 2026 review says the 2022 ESC/ERS guideline lists 30 mm or more, or a ratio above 0.9, among CT signs that suggest pulmonary hypertension. (Framingham 2012) (Sienkiewicz 2026, citing ESC/ERS 2022)

Does a wide pulmonary artery mean I have pulmonary hypertension?

Not on its own. A 2026 review says a single CT measurement does not establish pulmonary hypertension, and that the artery also gets wider with age, body size, lung disease and left heart disease. In a meta-analysis CT size picked up about 79% of people with pulmonary hypertension and was normal in about 83% of people without it. (Sienkiewicz 2026, citing ESC/ERS 2022) (Meta-analysis 2014)

Will I need an echocardiogram?

It depends on the rest of the picture. The 2026 review says a borderline size with no symptoms and no other CT signs is a risk marker rather than a reason for more tests, while a wide artery with other signs or unexplained breathlessness should lead to a clinical check and then an echocardiogram. Your doctor decides. (Sienkiewicz 2026, citing ESC/ERS 2022)

Is it linked to COPD or emphysema?

Yes, lung disease is one cause. In a large study of people with COPD, a pulmonary artery wider than the aorta was linked to a higher chance of severe flare-ups needing hospital care. MedlinePlus lists COPD and emphysema among the possible causes of pulmonary hypertension. (Wells 2012) (MedlinePlus)

What symptoms need a doctor?

The NHS advises seeing a GP for symptoms such as breathlessness, tiredness, feeling faint, chest pain, palpitations or swelling, and calling 999 (911 in the US) for sudden chest pain that does not stop after a few minutes, or palpitations with chest pain, breathlessness or feeling faint. (NHS)