High-Resolution CT of the Lungs

High-resolution CT (HRCT) of the lungs uses very thin slices and special reconstruction algorithms to assess lung tissue in detail. It is often used for interstitial lung disease and bronchiectasis.

How it differs from a standard chest CT

In HRCT, slices are very thin, often only a few millimeters, and the scan is usually performed without contrast. This allows fine structures such as airway walls and interlobular septa to be evaluated well.

The scanning pattern also differs, often done with the patient taking a deep breath and holding it to reduce motion.

Conditions assessed

HRCT is commonly used to evaluate interstitial lung diseases such as fibrosis, sarcoidosis, and pneumonitis. In bronchiectasis, it can show dilated airways.

HRCT also helps assess emphysema, small airway disease, and lung changes caused by certain infections.

Preparation and notes

Patients are usually asked not to smoke for a few hours before the exam, since smoking can change how the lungs appear. Contrast is generally not required.

The exam is often performed twice, once during deep inspiration and once during expiration, to assess air trapping.

Key points

• Very thin slices help show lung tissue detail.
• Usually performed without contrast.

Educational information, not a substitute for medical advice.