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High-Resolution Computed Tomography (HRCT)

High-Resolution Computed Tomography (HRCT): A Detailed Overview

High-Resolution Computed Tomography (HRCT) is a specialized computed tomography (CT) technique designed to enhance image resolution, particularly for assessing lung parenchyma and certain middle ear diseases[1]. HRCT is more precise than standard chest X-rays in diagnosing and monitoring lung tissue and airway diseases[3]. By using specific imaging parameters, HRCT provides detailed pictures of the lungs, allowing healthcare providers to diagnose and monitor various conditions affecting the small airways, air sacs (alveoli), and surrounding tissues[2].

Technique

HRCT is performed using a conventional CT scanner, but with specific adjustments to maximize spatial resolution[1]:

• Thin Sections: HRCT uses a narrow slice width, typically between 0.625 to 1.25 mm[5]. Historically, due to hardware limitations with earlier generation scanners, thin slices were defined as <3.0 mm, but modern technology allows for thinner slices[7].
• High Spatial Resolution Algorithm: A high spatial resolution image reconstruction algorithm is employed[1][5].
• Minimized Field of View: The field of view is minimized to reduce the size of each pixel, enhancing image detail[1].
• Optimized Scan Factors: Other scan factors, such as focal spot, may be optimized for resolution, potentially sacrificing scan speed[1].
• Inspiration and Expiration: Depending on the suspected diagnosis, the scan may be performed during both inspiration (prone position) and expiration (supine position)[1]. Expiration images can help identify air-trapping in patients with lung disease[4].

Historically, to assess generalized lung disease, thin sections were taken at 10-40 mm intervals, covering only about one-tenth of the lungs. However, modern CT equipment enables volume HRCT scans covering the entire lung tissue, and HRCT slices can also be constructed from contrast-enhanced CT scans of the chest[3]. Intravenous contrast agents are typically not used in HRCT of the lungs because of the lung’s inherent high contrast between soft tissue and air; contrast agents are more beneficial for assessing soft tissues and blood vessels[1].

Indications for HRCT

HRCT is indicated in various situations, including[4]:

• Chronic Diffuse Lung Disease:
  • Detection in patients with symptoms or pulmonary function tests suggestive of diffuse lung disease, but with normal or equivocal plain chest X-ray appearances.
  • Attempting a specific diagnosis when symptoms and/or plain chest X-ray findings are non-specific.
  • Assessing disease activity.
  • Selecting an optimal biopsy site.
• Acute Diffuse Lung Disease:
  • Detection in patients with symptoms or pulmonary function tests suggestive of acute lung disease (especially in immunosuppressed patients) but with normal or equivocal plain chest X-ray appearances.
  • Investigation of hemoptysis (coughing up blood) in selected patients.
  • Selecting an optimal biopsy site.

Other indications include:

• Industrial lung disease
• Idiopathic pulmonary fibrosis
• Connective tissue disease
• Radiation-induced lung disease
• Diffuse metastatic disease
• Sarcoidosis
• Mycobacterial infection
• Hypersensitivity pneumonitides
• Interstitial pneumonitis
• Histiocytosis X
• Lymphangiomyomatosis
• Cryptogenic organizing pneumonia (COP)
• Bronchiolitis obliterans organizing pneumonia (BOOP)
• Emphysema
• Bronchiectasis

Role of HRCT in Disease Management

HRCT plays a crucial role not only in the initial diagnosis but also in the follow-up of patients with established diffuse lung disease. Serial HRCT examinations can provide valuable information that cannot be determined from clinical history and other diagnostic tests[6]. The benefits of serial HRCT examinations include:

• Increasing the accuracy of initial diagnosis.
• Assisting in the estimation of prognosis.
• Identifying disease progression.
• Detecting new processes in patients with acute or worsening symptoms.
• Detecting other abnormalities or complications, such as lung cancer.

DrStemCellsThailand‘s Anti-Aging and Regenerative Medicine Center of Thailand and HRCT

At DrStemCellsThailand‘s Anti-Aging and Regenerative Medicine Center of Thailand, HRCT is utilized as a critical tool in our comprehensive patient evaluations, especially for those with respiratory conditions. We leverage HRCT to:

• Assess the extent and nature of lung damage prior to Cellular Therapy and Stem Cells.
• Monitor the effectiveness of stem cell treatments aimed at regenerating lung tissue and improving respiratory function.
• Evaluate patients with pre-existing lung conditions to determine their suitability for Cellular Therapy and Stem Cells.
• Track the progression of lung diseases and identify any complications.

By incorporating HRCT into our diagnostic and monitoring protocols, we ensure that our patients receive personalized and effective care tailored to their specific needs.

Consult with Our Team of Experts Now!

References

1. High-resolution computed tomography – Wikipedia. Link
2. HRCT (High-Resolution Computed Tomography) – Cleveland Clinic. Link
3. High-resolution CT of the lungs: Indications and diagnosis – PubMed. Link
4. High Resolution Computed Tomography (HRCT). Link
5. High-resolution CT | Radiology Reference Article | Radiopaedia.org. Link
6. The role of high-resolution computed tomography in the follow-up of …. Link
7. HRCT chest (protocol) | Radiology Reference Article – Radiopaedia. Link
8. High Resolution Computed Tomography of Lung. Link