From the Guidelines
High-Resolution Computed Tomography (HRCT) is associated with higher radiation exposure compared to a regular Computed Tomography (CT) scan, but the amount of exposure is low and the risk of radiation-induced malignancy on a per-scan basis is extremely low. When considering the diagnostic benefits of HRCT, particularly in evaluating diffuse lung diseases, the increased radiation risk is often outweighed by the need for detailed images of lung tissue 1. The distinction between HRCT and standard CT scans has become less clear with modern technology, as standard chest CT scans are often reconstructed using thin slices, similar to HRCT 1. However, HRCT typically includes additional imaging techniques, such as inspiratory prone images and supine end-expiratory imaging, which can increase radiation exposure 1. Key points to consider when weighing the risks and benefits of HRCT include:
- The sensitivity and specificity of HRCT for detecting interstitial lung disease (ILD), with a sensitivity of 95.7% and specificity of 63.8% 1
- The complementary information provided by HRCT and pulmonary function tests (PFTs) in diagnosing and monitoring ILD 1
- The potential risks of radiation exposure and incidental findings leading to additional testing, although the risk of radiation-induced malignancy is extremely low 1
- The preference of patients for more comprehensive screening, despite the potential risks 1. In clinical practice, the decision to use HRCT should be based on the individual patient's needs and risk factors, with consideration of the potential benefits and risks of radiation exposure 1.
From the Research
Radiation Exposure in HRCT and Regular CT Scans
- The study 2 found that the effective dose from a HRCT (0.98 mSv) is about 6.5 times less than the effective dose from a standard CT scan (6.5 mSv).
- Another study 3 measured the skin radiation dose in patients who had chest CT scans and found that HRCT scanning at 10- and 20-mm intervals produced 12% and 6%, respectively, of the radiation dose associated with conventional CT.
- A more recent study 4 compared the image quality, detailed morphology, and radiation dose of HRCT with photon-counting CT (PCCT) and energy-integrated CT (EICT), and found that PCCT enables improved resolution while reducing radiation dose by 47% in all patients, particularly pronounced in obese patients with 48.5% reduction.
Comparison of Radiation Dose
- The evidence suggests that HRCT is not necessarily associated with higher radiation exposure compared to a regular CT scan, and in some cases, HRCT can produce significantly less radiation than conventional CT 2, 3.
- However, the radiation dose of HRCT can vary depending on the scan parameters and techniques used, such as the use of PCCT or EICT 4.
- The study 5 discussed the importance of considering radiation issues in HRCT scans, including the risk from radiation, recommended dose levels, and radiation dose reduction strategies.