Does High-Resolution Computed Tomography (HRCT) use contrast dye?

From the Guidelines

High-Resolution Computed Tomography (HRCT) typically does not use contrast dye. Standard HRCT scans of the lungs are performed without intravenous contrast as the natural contrast between air-filled lungs and surrounding tissues provides excellent visualization of lung parenchyma, small airways, and interstitial patterns. This technique is specifically designed to evaluate fine lung details with high spatial resolution, making it ideal for diagnosing interstitial lung diseases, bronchiectasis, and early emphysema.

Key Points

• The use of contrast material is not involved in HRCT scans, as stated in the guidelines for the use of spiral computed tomography in screening for lung cancer 1.
• The American College of Radiology (ACR) Appropriateness Criteria for diffuse lung disease also supports the use of non-contrast HRCT for initial imaging, with no relevant literature to support the use of CT with intravenous (IV) contrast for this purpose 1.
• However, in certain clinical scenarios such as evaluating for pulmonary embolism, vascular abnormalities, or when assessing for enhancement patterns in suspected tumors, contrast may be added to the protocol, which would then be considered contrast-enhanced CT scans rather than traditional HRCT.
• The non-contrast approach also benefits patients with kidney problems or contrast allergies who might be at risk from contrast administration.

Clinical Considerations

• The ACR practice parameter for HRCT recommends thin-slice acquisition and high spatial resolution reconstruction algorithms for HRCT scans, which allows for near-isotropic voxels and provides additional tools for a thorough evaluation of the imaged field 1.
• The addition of contrast to HRCT scans may allow for improved visualization of the mediastinum, chest wall, and soft tissues, but it is unlikely that clinically significant mediastinal lymphadenopathy would be overlooked on a noncontrast scan.
• The most recent and highest quality study, published in 2021, supports the use of non-contrast HRCT for initial imaging of diffuse lung disease 1.

From the Research

HRCT and Contrast Dye

• High-Resolution Computed Tomography (HRCT) is a method of examination that is more precise than chest X-ray in the diagnosis and monitoring of diseases of the lung tissue and the airways 2.
• HRCT slices can also be constructed from contrast-enhanced CT scans of the chest or the whole body, indicating that contrast dye can be used in HRCT scans 2.
• The use of contrast dye in HRCT is not explicitly stated as a requirement, but it can be used to enhance the diagnosis of certain conditions.

Indications for HRCT

• HRCT of the lungs can be applied to the diagnosis of both acute and more chronic diffuse diseases of the lung tissue and the airways 2.
• The best-known indications for HRCT include idiopathic interstitial pneumonias, such as idiopathic pulmonary fibrosis, and pneumoconiosis, such as asbestosis 2.
• More acute indications for HRCT include various inflammations, drug reactions, and diffuse alveolar injury 2.

Contrast Dye and Nephrotoxicity

• Contrast media can lead to acute renal failure that may occasionally require hemodialysis 3, 4, 5.
• The risk factors for contrast-induced nephropathy include preexisting renal insufficiency, diabetes mellitus, and the use of certain medications such as angiotensin-converting enzyme (ACE) inhibitors 3, 5, 6.
• The optimal strategy to prevent contrast-associated nephrotoxicity remains uncertain, but recommendations include periprocedural hydration, use of a low-osmolality contrast, and limiting the amount of contrast agent 5.