What it is (overview)

A CT Chest High Resolution scan (often called HRCT) is a specialized type of CT scan used for detailed chest imaging. It creates very thin “slice” pictures of your lungs and nearby structures (airways, blood vessels, pleura/lining around the lungs, and parts of the chest wall). Compared with a standard chest CT, high-resolution imaging is optimized to show fine lung detail—especially the lung tissue (the interstitium) and small airways.

The test does not measure a blood value; instead, it produces high-detail images that a radiologist interprets. Your results typically describe findings such as:

Normal / no significant abnormality: No concerning scarring, inflammation, fluid, or suspicious nodules are seen.

Inflammation or infection patterns: Areas such as “ground-glass opacities” or consolidation may suggest pneumonia or other inflammatory lung conditions (the report will often recommend correlation with symptoms and labs).

Scarring or interstitial changes: Findings like reticulation, honeycombing, or traction bronchiectasis can point toward interstitial lung disease or pulmonary fibrosis and can help determine severity and distribution.

Nodules or masses: The scan may detect pulmonary nodules and characterize their size, location, and features. Many nodules are benign, but some require follow-up imaging or additional testing.

Airway disease: Signs of small airway narrowing or air-trapping can support diagnoses like asthma-related changes, bronchiolitis, or COPD patterns.

HRCT is commonly performed without contrast, but some clinical questions may still require IV contrast or additional CT techniques. Your clinician uses the imaging results together with your history, physical exam, and other tests (like pulmonary function tests) to guide diagnosis and treatment.

When & why it's usually done

A doctor may order a CT Chest High Resolution scan when symptoms, exam findings, or prior imaging suggest a lung problem that needs a closer look. It is especially helpful for evaluating respiratory symptoms that are persistent or unexplained and for clarifying findings on a chest X-ray or standard CT scan.

Common reasons include:

Ongoing or unexplained symptoms such as chronic cough, shortness of breath (especially with exertion), wheezing, chest tightness, or reduced exercise tolerance.

Abnormal chest imaging (X-ray or CT) showing possible scarring, hazy areas, inflammation, or nodules that require better characterization with high-resolution chest imaging.

Suspected interstitial lung disease, including evaluation of patterns that can help narrow the cause (for example, autoimmune-related lung disease, occupational exposures, or idiopathic pulmonary fibrosis).

Monitoring known lung disease to assess progression, response to treatment, or complications (for example, worsening fibrosis, superimposed infection, or medication side effects).

Evaluation of nodules found incidentally or during screening, to help determine whether a nodule is likely benign, needs short-term follow-up, or requires additional work-up.

Assessment of infection complications or difficult-to-diagnose infections, especially in people with weakened immune systems or persistent symptoms despite treatment.

Risk factors and exposures such as smoking history, certain workplace exposures (silica, asbestos), significant mold or bird exposure (hypersensitivity pneumonitis), prior radiation therapy, or use of medications known to affect the lungs.

Because HRCT uses X-rays, it involves radiation exposure. Your healthcare team weighs the benefits of accurate diagnosis and management against this risk, and uses the lowest appropriate dose for diagnostic quality when possible.

Common diseases related to it

• Interstitial lung disease (ILD)
• Idiopathic pulmonary fibrosis (IPF)
• Hypersensitivity pneumonitis
• Sarcoidosis
• Connective tissue disease–associated ILD (e.g., rheumatoid arthritis, scleroderma)
• Occupational lung disease (asbestosis, silicosis)
• Chronic obstructive pulmonary disease (COPD) and emphysema
• Bronchiectasis
• Bronchiolitis / small airways disease with air-trapping
• Pneumonia and atypical lung infections
• Pulmonary nodules (benign nodules and possible lung cancer evaluation)
• Pleural disease (pleural thickening, pleural effusion evaluation)

Health goals where it may help

• Getting a clearer diagnosis for ongoing cough, shortness of breath, or other respiratory symptoms
• Early detection and characterization of lung scarring and interstitial lung disease to guide treatment
• Monitoring progression of chronic lung disease and response to therapy over time
• Evaluating and following pulmonary nodules with appropriate surveillance plans
• Checking for complications from infections or assessing persistent/recurrent infections
• Assessing the impact of smoking, occupational exposures, or environmental triggers on lung health
• Supporting treatment planning (e.g., need for specialist referral, further testing, or medication adjustments)