HRCT Chest (High-Resolution) — Dictation, Appropriateness, and Dose for Residents

1. The Attending Expects an Interstitial Lung Disease Pattern, Not Just a Description

It’s 11 AM on your chest rotation. The list is full of outpatient High-Resolution CT (HRCT) scans for chronic dyspnea. The next one up is a 68-year-old with a dry cough and progressive shortness of breath. Your attending is a thoracic specialist who lives and breathes interstitial lung disease (ILD). They don’t just want a description of ground-glass opacities and reticulation; they expect you to commit to a pattern—UIP, NSIP, HP—and explain your reasoning based on the 2018 ATS/ERS guidelines. You know the key is the distribution: subpleural and basal for UIP, subpleural sparing for NSIP, centrilobular for HP. But getting the phrasing just right, especially when honeycombing is borderline, is where the pressure mounts.

When I was a fellow, memorizing these patterns felt like learning a new language. You need the right words in the right order, and you need them fast. This guide is built for that moment—to give you the structure and key phrases to confidently call ILD patterns. For more tools like this, check out the residents free-reference hub, which has other templates and clinical calculators we’ve built for trainees.

2. What a High-Resolution CT (HRCT) of the Chest Covers and What Attendings Look For

An HRCT of the chest is the diagnostic gold standard for evaluating suspected interstitial lung disease. It uses thin-slice, non-contrast images with a high-resolution reconstruction algorithm to provide exquisite detail of the lung parenchyma. Unlike a routine chest CT, its entire purpose is to characterize the pattern and distribution of diffuse lung disease. Optional expiratory and prone series are critical for diagnosing small airways disease and differentiating true fibrosis from atelectasis.

Your attending expects a systematic evaluation that leads to a specific ILD pattern diagnosis when possible. Your report should clearly address:

• ILD Pattern: Is there evidence for Usual Interstitial Pneumonia (UIP), Nonspecific Interstitial Pneumonia (NSIP), Hypersensitivity Pneumonitis (HP), Organizing Pneumonia (OP), Sarcoidosis, or Lymphangioleiomyomatosis (LAM)?
• Key Fibrotic Features: Presence, character, and distribution of honeycombing, traction bronchiectasis, and reticulation.
• Air Trapping: Is there mosaic attenuation that accentuates on the expiratory series? This is a pivotal finding for HP and constrictive bronchiolitis.
• Nodule Distribution: Are nodules perilymphatic (sarcoidosis), centrilobular (HP), or random (miliary infection/mets)?
• Distribution of Disease: Is the pattern upper-lobe predominant (sarcoidosis, HP), lower-lobe predominant (UIP, NSIP), peripheral/subpleural (UIP, OP), or central/peribronchovascular?
• Pleural and Mediastinal Findings: Note any effusions, thickening, or lymphadenopathy.

3. Radiology Report Template for High-Resolution CT (HRCT) Chest

This template provides a solid framework for your HRCT dictations. The key is to be descriptive in the findings and definitive (when possible) in the impression, referencing the established classification systems.

Technique

High-resolution non-contrast CT of the chest was performed with volumetric acquisition at full inspiration. Additional images were obtained at end-expiration [and in the prone position at end-inspiration]. Images were reconstructed using a high-spatial-frequency algorithm.

Findings

COMPARISON: [Date of prior study]

LUNGS:
Parenchymal Pattern: [e.g., Reticulation, ground-glass opacity, honeycombing, consolidation, nodules, cysts, mosaic attenuation, traction bronchiectasis/bronchiolectasis]
Distribution: [e.g., Upper vs. lower lobe predominance; central vs. peripheral; subpleural vs. peribronchovascular]
Ancillary Findings: [e.g., Centrilobular nodules, septal thickening, architectural distortion]
Expiratory Series: [e.g., No significant air trapping. // Findings of air trapping are seen in the following distribution: …]
Prone Series: [e.g., Posterior basal opacities resolve, consistent with dependent atelectasis. // Posterior basal subpleural reticulation and traction bronchiectasis persist, consistent with fibrosis.]

AIRWAYS: Trachea and central bronchi are patent. No evidence of central bronchiectasis.

PLEURA: No pleural effusion or thickening. No pneumothorax.

MEDIASTINUM AND HILA: No mediastinal or hilar lymphadenopathy. The heart and great vessels are normal in size and contour.

CHEST WALL AND UPPER ABDOMEN: Visualized osseous structures are unremarkable. Visualized upper abdominal organs are unremarkable.

Impression

1. Findings consistent with a [UIP / Probable UIP / Indeterminate for UIP / NSIP / Organizing Pneumonia / Hypersensitivity Pneumonitis] pattern. Key features include [basal and subpleural predominant honeycombing and traction bronchiectasis // basal predominant ground-glass with subpleural sparing // mosaic attenuation with air trapping and centrilobular nodules].

2. [Ancillary findings, e.g., No evidence of significant air trapping on expiratory images.]

3. [Comparison statement, e.g., Findings are stable/progressive compared to the prior study from [Date].]

4. Free Template Sources for Other Modalities

Building your own template library is a rite of passage in residency. But you don’t have to start from scratch. For other modalities and subspecialties, two great free repositories exist that are curated by and for radiologists. They are excellent sources for building out your personal macro library.

• RadReport.org: Maintained by the RSNA, this is a comprehensive library of peer-reviewed templates covering nearly every study type.
• Radiology Templates (AU): A fantastic, well-organized collection from our Australian colleagues with clean, practical templates for daily use.

5. The Next-Level Move: Free-Form Dictation to Structured Report

Templates are essential, but they can feel rigid. Sometimes you just want to dictate the positive findings as you see them, especially on a complex case. This is where AI-powered tools can streamline your workflow. Instead of clicking through a structured template, you can dictate naturally: “Subpleural and basal-predominant honeycombing with associated traction bronchiectasis. No significant ground glass to suggest an alternative diagnosis.”

The system then parses your free-form dictation and organizes it into a perfectly structured report. GigHz Precision AI is designed for this exact workflow, using official templates from the ACR and other societies. It helps ensure your reports are complete and consistent without forcing you into a rigid, click-box-style of reporting. It also surfaces relevant Clinical Decision Support (CDS) guidance based on your findings, helping you make the right recommendations every time.

6. When Should You Order a High-Resolution CT (HRCT) of the Chest? ACR Appropriateness Criteria

The decision to order an HRCT is guided by specific clinical questions, primarily related to diffuse, non-acute lung disease. The American College of Radiology (ACR) provides clear guidance on this.

For a patient with suspected diffuse lung disease on initial imaging, an HRCT of the chest is rated Usually Appropriate (7/9). This is the first-line advanced imaging test. The same applies to routine follow-up or evaluation for an acute exacerbation of known diffuse lung disease.

In the workup of chronic dyspnea of non-cardiac origin, HRCT is also Usually Appropriate for several scenarios, including when the cause is unclear, when small airways disease is suspected, or in patients with known or suspected prior COVID-19 infection. For a chronic cough lasting more than 8 weeks, HRCT is considered Usually Appropriate, especially if initial evaluation and empiric treatment have failed. The primary alternative for definitive diagnosis, when imaging is non-diagnostic, is a surgical lung biopsy.

7. How Much Radiation Does a High-Resolution CT (HRCT) of the Chest Deliver?

An HRCT of the chest is a relatively low-dose study compared to many other CT protocols. The estimated effective dose is typically in the range of 2-5 mSv. This places it in the low-to-moderate exposure tier, comparable to several months to a few years of natural background radiation that we all receive annually.

Dose is managed through several techniques. Modern scanners use iterative reconstruction algorithms and automated tube current modulation to reduce dose while maintaining high image quality. The original HRCT protocol, which used sequential 1 mm slices spaced 10 mm apart, was inherently low-dose. While modern volumetric acquisitions provide more data, they are still optimized for low radiation exposure. Adding a prone series increases the total dose, so it should only be performed when clinically indicated to evaluate posterior basal disease.

8. High-Resolution CT (HRCT) Chest Imaging Protocol — Phases, Contrast, and Reconstructions

The HRCT protocol is designed for maximum parenchymal detail without the need for intravenous contrast. The key is thin-slice acquisition with a sharp reconstruction kernel, supplemented by specific respiratory maneuvers to answer questions about air trapping and dependent atelectasis.

The protocol typically includes a primary inspiratory scan, with optional but high-yield expiratory and prone scans added based on the clinical indication or institutional preference.

Common protocol pitfalls:

• Skipping the Expiratory Phase: The expiratory series is essential for diagnosing air trapping, a key feature of hypersensitivity pneumonitis and small airways disease. Some centers add it to all HRCTs, while others reserve it for specific indications. When in doubt, it’s better to have it.
• Inadequate Breath-Hold Coaching: The quality of an HRCT depends heavily on the patient’s ability to perform deep inspiration and forced expiration. Poorly coached breath-holds can create motion artifacts or mimic disease.
• Unnecessary Prone Imaging: Prone scans add radiation dose and time. They should be used selectively, specifically when posterior basal subpleural disease is the primary question, to differentiate fibrosis from simple atelectasis.

9. The 3-Months-Free Offer for Radiology Residents and Fellows

3+ months free for radiology residents and fellows

Look like a rockstar on your reports — dictate positive findings in free form, and the AI generates a structured report using ACR + SIR templates with the appropriate clinical decision support firing automatically. All we ask is feedback so we can keep improving the product for trainees.

Signup is simple. No credit card, no long forms. To apply, just provide these three items:

1. PGY year (e.g., PGY-2, PGY-4)
2. Training type (radiology residency or specific fellowship — IR, body, MSK, neuro, peds, breast, nucs)
3. Training program / hospital name
4. (Optional) institutional email

Ready to give it a try? Apply for the residents free-access program and we’ll get you set up.

10. Frequently Asked Questions (FAQ)

Is it HIPAA-compliant?

Yes. The platform is designed for de-identified workflows by default. No patient-identifying information is required or stored. All data is handled in a secure, HIPAA-compliant environment.

Do I need my hospital’s IT department to set it up?

No. GigHz Precision AI is browser-based and requires no local software installation or IT involvement. It works on any modern computer, including the call-room PC or your personal iPad.

Does it work with PowerScribe or other dictation systems?

Yes. It works alongside your existing dictation system. You can dictate into our web interface, and the structured report can be copied and pasted directly into your PACS/RIS in a single click.

Can I use it on my phone or iPad?

Absolutely. The platform is fully responsive and designed to work on desktops, tablets, and mobile devices, making it accessible whether you’re in the reading room or on the go.

Can I customize the templates?

Yes. While the system comes pre-loaded with official society templates (ACR, SIR, etc.), you can create, modify, and save your own custom templates to match your personal or institutional preferences.

What happens after my residency or fellowship ends?

We offer straightforward conversion paths for trainees who want to continue using the platform in their post-training practice. Special pricing is available for recent graduates.

Free GigHz Tools That Pair With This Article

Three free tools that complement the material above:

• ACR Appropriateness Criteria Lookup — Type an indication or clinical scenario in plain language and get the imaging studies the ACR rates for it, with adult and pediatric radiation levels. Built directly from 297 ACR topics, 1,336 clinical variants, and 15,823 procedure ratings.
• GigHz Imaging Protocol Library — A searchable library of 131 imaging protocols with the physics specs surfaced and the matching ACR Appropriateness Criteria alongside. Plain-English narratives readable in 60 seconds, organized by modality.
• GigHz Radiation Dose Calculator — Pick the imaging studies a patient has had and see total dose in millisieverts (mSv) with comparisons to natural background radiation, transatlantic flights, and chest X-rays. Useful for shared decision-making.

Reviewed by Pouyan Golshani, MD, Interventional Radiologist — May 7, 2026