Chest HRCT

CT scans are usually not recommended in pregnant women, as the x-ray radiations may harm the unborn baby.

HRCT is done in people who have symptoms suggestive of interstitial lung disease, such as:

• Dry cough
• Shortness of breath
• Fatigue
• Weight loss

HRCT can be ordered for suspected short-term interstitial lung disease in the following situations:

• If chest x-rays are normal, but symptoms or pulmonary function test results suggest interstitial lung disease (commonly seen in people who have lowered immunity)
• To select an optimal site for collecting a lung tissue sample for testing (biopsy)
• To diagnose the cause for coughing up blood (haemoptysis) in some people

HRCT may be ordered in people with suspected long-term interstitial lung disease in the following situations:

• Normal chest x-rays despite the presence of symptoms or pulmonary test results that suggest interstitial lung disease
• If the symptoms and chest x-ray findings are nonspecific to confirm a diagnosis
• To identify an optimal site for biopsy
• To assess the activity of the disease

Since the year 2020, doctors have ordered HRCT Chest for patients of COVID-19 to determine the severity of the infection as well.

Before the scan, you may be asked to put on a hospital gown. You will need to remove all jewellery and other metal accessories as it may affect the test equipment.

The procedure for the scan is as given below:

• You will be positioned on the movable exam table of a CT scan machine.
• Your doctor may first ask you to lie on your back with arms outstretched over your head and then turn and lie on your stomach. 
• The table will move into the scanner, and a series of images will be taken.
• Before beginning the procedure, the technologist will step out to operate the machine from an adjoining room. You will be able to talk to them via an intercom.
• You will be asked to keep still during the imaging. Your technician will also instruct you to breathe in, breathe out or hold your breath at times.

The procedure takes about 15 minutes to half an hour.

The scan is painless. You may hear clicking and buzzing sounds when the equipment is capturing the images. Try not to panic as this is normal. You can resume your routine diet and activities after the test.

Abnormal results of the test can be seen in diffuse lung conditions that involve the interstitium, such as:

• Interstitial lung disease
• Early interstitial lung disease
• Small airways disease (conditions affecting the small airways called bronchioles)
• Bronchiectasis (a long-term condition in which the walls of the major airways called bronchi become thickened and inflamed due to infection and inflammation)
• Cystic lung disease (a group of diseases characterised by multiple air-filled sacs called cysts in the lungs)
• Pulmonary micronodules (small round growths in the lung)
• Bronchial asthma (a condition in which the bronchi in the lungs become constricted due to stimuli)
• Emphysema (a condition that damages the air sacs in the lungs)

Chest HRCT scan has the following benefits:

• It is painless, fast and accurate
• It gives detailed images of parts inside the body without surgery
• There is no radiation left in the body once the scan is done

This procedure has no risks but pregnant women should not undergo this scan as exposure to X-ray radiation may lead to birth defects in the baby.

Some tests that can be performed with the HRCT scan are:

• Pulse oximetry
• Spirometry
• Chest x-ray
• Bronchoscopy
• Surgical biopsy

During the COVID-19 pandemic, HRCT Chest has been helpful in finding out the extent of the infection, the probability of complications caused by the infection and the prognosis of the patient. The test is usually ordered in the case of suspected or confirmed COVID-19 patients who present with mild to severe symptoms. The imaging results help medical professionals decide the course of treatment, including whether the patient should be admitted to the hospital or given homecare. Those with comorbidities like diabetes, hypertension or ischemic heart disease are considered to be at a higher risk of COVID-19 complications and thus, may be asked to get the scan for that reason.

As per studies, the most common manifestation of COVID-19 pneumonia that can be seen in HRCT results is GGO (Ground-glass opacification/opacity), which refers to the area with increased opacity in the lungs or the spaces in the lungs that look hazy in the images. An HRCT score may also be given to the patient which would reflect the severity of the disease. Once you get an HRCT Chest scan done, do consult your doctor with the result to get an accurate diagnosis and prognosis of your condition.

Disclaimer: All results must be clinically correlated with the patient’s complaints to make a complete and accurate diagnosis. The above information is provided from a purely educational point of view and is in no way a substitute for medical advice by a qualified doctor.