CT Chest High Resolution without Contrast
In a high-resolution CT scan of the chest, a higher dose of X-rays is used, collimated to a much thinner slice width to accurately show the interstitium of the lungs with exquisite details. HRCT is preferred over conventional CT scans when finer details of the lung tissues (parenchyma) are required in conditions such as idiopathic interstitial pneumonia, pulmonary fibrosis, pneumoconiosis, diffuse alveolar injury, etc.
In HRCT without contrast, no contrast agent is used.
Why and when do you need this test?
You may be advised for this test if you have signs and symptoms of lung disease or when other medical tests related to the lungs have deranged results that may need further evaluation.
Some of the indications for performing an HRCT chest include the following;
- Shortness of breath
- Progressive cough
- Labored breathing
- Chest tightness
- Coughing up blood or sputum
- Suspecting diffuse lung disease (DLD)
- Covid 19 infection
- To identify cystic or nodular lung disease
- Suspecting small airways disease
- To detect the progression of an already diagnosed disease or to monitor the efficacy of treatment
- To evaluate the abnormalities of pulmonary blood vessels
Do you need to prepare for the test?
- You can eat food, drink fluids and take medications normally unless your doctor advises otherwise.
- You would be asked to remove jewelry, metal clips, or any metallic thing that can interfere with the radiation and may affect the image.
- You should wear loose, easy clothing to feel comfortable.
- Inform the doctor if you are pregnant, as this test uses X-rays which can harm a fetus.
What can you expect?
- You will be asked to lie down on the table that will slide into the CT scan machine that looks like a large donut with a tunnel.
- You need to lie down still and not move to prevent the images from getting blurry.
- If you feel uneasy at closed paces, you may ask for relaxing medicine.
- You will be alone in the room but under the constant care of a technician across the glass window who will be talking to you.
- It is a painless procedure that lasts for about 15-30 minutes but may take longer.
Are there any risks to this test?
You can discuss with your doctor the dose of X-rays used in the test and its necessity according to your disease and previous radiation exposure.
The X-rays can harm the baby inside the mother’s womb, so don’t forget to inform your doctor about your pregnancy.
What do the test results mean?
A signed report will be sent to your doctor by the radiologist. Your doctor would be able to tell you in detail about your results.
Some of the abnormal results may include the following;
- Diffuse lung disease
- Interstitial lung disease (idiopathic interstitial pneumonia)
- Idiopathic pulmonary fibrosis
- Pulmonary micronodules
- Bronchiolitis obliterans
- Silicosis or coal worker's pneumoconiosis
- Miliary tuberculosis
- Fungal pneumonia
- Hematogenous metastasis of cancers
- Chronic pulmonary vascular disease
- Enlarged lymph nodes
Other related tests may include:
- MRA (magnetic resonance angiography)
- CT chest (computed tomography)