How Often Do You Need CT Scans and Breathing Tests for ILD?

Monitoring Interstitial Lung Disease (ILD) requires a regular schedule of breathing tests and imaging to track whether the disease is stable or progressing. However, there is no one-size-fits-all schedule ^[1].

Testing is often more frequent (such as every 3 to 6 months) soon after diagnosis, during active disease, or when starting a new treatment. For stable patients, monitoring may happen less often. Your care team will personalize your schedule based on your specific type of ILD, your symptoms, and how your lungs are functioning over time.

Why We Monitor ILD

ILD encompasses many different conditions with different disease courses. While some people remain stable for long periods, others may experience progression that reduces lung function ^[2]. Because structural changes in your lungs can happen before you notice a difference in how you feel, objective measurements are critical. Routine monitoring helps your doctor determine if your current treatment is working or if your care plan needs adjusting ^[3].

Breathing Tests (PFTs): Your Main Tracking Tool

Your doctor will rely heavily on Pulmonary Function Tests (PFTs) to track the health of your lungs. Because these tests are safe and do not involve radiation, they are the preferred way to track your condition frequently.

Two key numbers your doctor will watch are:

• Forced Vital Capacity (FVC): This measures the total amount of air you can exhale forcefully after taking a deep breath. A confirmed drop in your FVC over time can be a warning sign of disease progression ^[4].
• Diffusing Capacity for Carbon Monoxide (DLCO): This uses a safe test gas to estimate how well oxygen passes from your lungs into your blood. Lower DLCO values can also indicate progression ^[5].

Understanding Your Results: One lower-than-normal reading does not automatically mean your disease is worsening. Test results can be affected by your effort that day, a recent illness, or other factors. Your care team will look at trends over multiple tests, combined with how you are feeling, before making treatment decisions.

CT Scans (HRCT): Detailed Imaging

A High-Resolution Computed Tomography (HRCT) scan provides detailed cross-sectional X-ray images of your lungs. It is highly sensitive for showing the patterns and extent of scarring (fibrosis) or other structural abnormalities ^[3].

However, because CT scans involve ionizing radiation, doctors weigh the benefit of the information against the radiation exposure. There is no universal rule requiring an annual HRCT scan for every ILD patient ^[1]. While a 12-month interval is sometimes used in research or for high-risk patients ^[6], your doctor may only recommend a repeat scan to answer a specific clinical question, such as:

• You have high-risk features associated with an underlying autoimmune disease ^[7].
• Your PFT numbers show a meaningful, confirmed decline.
• You experience a significant worsening of symptoms ^[8].

Oxygen and Exercise Testing

Your care team won’t just look at scans and breathing tests; they will also monitor your oxygen levels. You might have normal oxygen levels while resting but experience exertional desaturation (a drop in blood oxygen) when moving ^[9].

To safely check for this, your doctor may have you perform a clinically supervised 6-minute walk test. This test involves walking at your own pace while your heart rate and oxygen levels are monitored by a professional, providing an objective measure of your exercise capacity ^[10].

Note on home oximeters: If you use a pulse oximeter at home, remember that readings can be affected by cold fingers, poor circulation, nail polish, and darker skin tones. Always follow your care team’s specific action plan if you get an unexpected reading.

When to Seek Immediate Help

You do not need to wait for your next scheduled test if you feel worse. An acute exacerbation is a sudden, serious worsening of your ILD that requires prompt medical evaluation, not just waiting for a routine scan ^[11].

Seek emergency medical care (call 911 or go to the nearest emergency room) if you experience:

• Severe breathlessness at rest
• Inability to speak in full sentences
• Chest pain
• Fainting or confusion
• Blue lips or fingertips
• Markedly low oxygen levels that do not improve with your prescribed resting oxygen settings