Pulmonary Infarction
Pulmonary infarction occurs when a segment of lung tissue dies due to a lack of blood supply. This can happen when a blood clot blocks the arteries that supply the lungs, often as a complication of a pulmonary embolism. When doctors suspect this condition, they use imaging tests like X-rays and CT scans to confirm the diagnosis. If you’ve seen “pulmonary infarction” on a radiology report, you might wonder what it means and what the images show.
Understanding Pulmonary Infarction Through Imaging
Radiologists rely on imaging to detect pulmonary infarction. The condition often appears as a wedge-shaped abnormality in the lung. Various imaging techniques help confirm the diagnosis and rule out other lung diseases.
Chest X-ray Findings in Pulmonary Infarction
A chest X-ray is often the first test used to evaluate lung problems. However, its ability to detect pulmonary infarction is limited. If a pulmonary infarction is present, the following signs might be visible:
•Hampton’s Hump – A wedge-shaped opacity near the lung’s outer edge, indicating an infarcted area.
•Pleural Effusion – Fluid accumulation around the lung, which may appear as a blunted costophrenic angle.
•Elevated Diaphragm – Due to lung volume loss from infarction.
Despite these findings, chest X-rays alone are not definitive. Many cases of pulmonary infarction are missed on X-rays, making further imaging necessary.
CT Scan: The Gold Standard for Diagnosis
A CT pulmonary angiogram (CTPA) is the most accurate imaging test for pulmonary infarction. This specialized CT scan uses contrast dye to highlight blood flow in the lungs, allowing radiologists to detect blockages and infarcted areas. Key CT findings include:
•Wedge-shaped Peripheral Opacity – The infarcted tissue often appears as a dense, triangular area pointing toward the lung center.
•Lack of Enhancement – The affected tissue does not take up contrast dye, confirming its poor blood supply.
•Pulmonary Embolism – CT scans often reveal a clot in the pulmonary arteries, the most common cause of infarction.
•Pleural-Based Consolidation – The infarcted lung tissue may appear dense due to inflammation and hemorrhage.
MRI in Pulmonary Infarction: When Is It Used?
Magnetic resonance imaging (MRI) is rarely used for pulmonary infarction. However, it may be helpful in patients who cannot tolerate contrast dye. MRI can show lung abnormalities using special sequences, but it is not the first-line test.
Ultrasound and Pulmonary Infarction
Ultrasound is not commonly used for detecting pulmonary infarction, but it can help identify related complications such as pleural effusion. In some cases, Doppler ultrasound is used to detect deep vein thrombosis (DVT) in the legs, which is a common source of pulmonary emboli leading to infarction.
How Radiologists Interpret Pulmonary Infarction
Radiologists carefully analyze imaging studies to distinguish pulmonary infarction from other lung conditions like pneumonia, tumors, or atelectasis. When they see a wedge-shaped opacity on CT, they assess whether a pulmonary embolism is present. If a clot is visible in the pulmonary arteries, the diagnosis of infarction becomes more likely.
In my practice, pulmonary infarction is often found in patients who come to the emergency room with sudden shortness of breath and chest pain. Many of these patients have underlying risk factors like recent surgery, prolonged immobility, or a history of blood clots. When I see a wedge-shaped lung abnormality on a CT scan, I always check for an associated pulmonary embolism to guide treatment decisions.
Common Causes and Risk Factors for Pulmonary Infarction
Pulmonary infarction most commonly results from a pulmonary embolism, which occurs when a blood clot travels to the lungs from another part of the body. Other causes include:
•Hypercoagulable States – Conditions like cancer, pregnancy, or genetic clotting disorders increase the risk of clot formation.
•Immobility – Long periods of inactivity, such as during hospital stays or long flights, can contribute to clot formation.
•Heart Disease – Conditions like atrial fibrillation can lead to blood clots traveling to the lungs.
•Trauma or Surgery – Recent surgery or injury can increase the likelihood of clotting.
Treatment and Prognosis
Once pulmonary infarction is diagnosed, treatment focuses on addressing the underlying cause. This often includes:
•Blood Thinners (Anticoagulants) – Medications like heparin or warfarin prevent further clot formation.
•Oxygen Therapy – Helps improve oxygen levels in patients with significant lung involvement.
•Pain Management – Infarction can cause chest pain, which may require medication.
In most cases, pulmonary infarction heals over time, but severe cases may lead to complications like lung scarring. Regular follow-up imaging may be needed to monitor recovery.
Conclusion
Pulmonary infarction is a condition where lung tissue dies due to blocked blood flow, most commonly from a pulmonary embolism. While chest X-rays can show signs of infarction, CT pulmonary angiography is the best imaging test for diagnosis. Radiologists look for a wedge-shaped opacity and an associated pulmonary embolism to confirm the condition. Early detection and treatment with blood thinners can prevent complications and improve outcomes. If your radiology report mentions pulmonary infarction, your doctor will use this information to guide your treatment plan.
References
1.https://radiopaedia.org/articles/pulmonary-infarction-1?lang=us
2.https://www.sciencedirect.com/science/article/pii/S0049384824002032
3.https://www.resmedjournal.com/article/S0954-6111(18)30116-1/fulltext