Interpretation of Imaging Chapter 1: Why High-Resolution Computed Tomography (HRCT) Matters

Watch Chapter 2 here.

Hello, and welcome back to the Interstitial Lung Disease Explainer Video Series. I am Dr Joseph Mammarappallil, a cardiothoracic radiologist at The Duke Medical Center. This series focuses on interpreting high-resolution computed tomography, or HRCT, specifically in diagnosing and characterizing progression in interstitial lung diseases, or ILDs. In this video, you will learn how to recognize key imaging patterns, understand their clinical implications, and integrate radiology findings into multidisciplinary care. 

HRCT is the gold standard imaging tool for ILD assessment. With its thin-section images and high spatial resolution, HRCT offers a more precise characterization of architectural changes in ILD. These features cannot be visualized on plain radiographs. 

For rheumatologists managing patients with systemic autoimmune rheumatic diseases, or SARDs, the 2023 ACR and CHEST guidelines conditionally recommend HRCT for both screening those at risk and monitoring for disease progression. HRCT is a fundamental diagnostic tool for evaluating the natural history of these diseases, supporting early diagnosis, assessing severity, stratifying prognosis, tracking progression, and promptly identifying short- and long-term complications. 

By revealing distinct imaging patterns—such as ground-glass opacities, reticulations, honeycombing, or traction bronchiectasis—HRCT allows for the characterization and distribution of these features, offering the pattern recognition needed to assess fibrosis and monitor its progression over time.

It is, however, important to remember that HRCT must be interpreted in conjunction with clinical findings and serologic and pathologic data. It is best used during multidisciplinary discussions to establish a clinical diagnosis.

The key is making sense of complex HRCT images. By integrating imaging with the patient’s symptoms, lab results, and clinical profile, structured HRCT interpretation turns scan patterns into clear, actionable endpoints that guide patient care. 

The key takeaway is that HRCT brings clarity to the clinical picture of ILD. With the support of multidisciplinary colleagues, even complex scans become manageable. This structured approach not only guides diagnosis and monitoring but also creates a clear clinical story that supports ongoing management decisions. 

ACR – American College of Rheumatology 

ATS – American Thoracic Society 

CHEST – American College of Chest Physicians 

CTD-ILD – Connective Tissue Disease–Related Interstitial Lung Disease 

DLCO – Diffusing Capacity of the Lung for Carbon Monoxide 

ERS – European Respiratory Society 

FVC – Forced Vital Capacity 

GGO – Ground-Glass Opacity 

HRCT – High-Resolution Computed Tomography 

ILD – Interstitial Lung Disease 

IPF – Idiopathic Pulmonary Fibrosis 

JRS – Japanese Respiratory Society 

LIP – Lymphocytic Interstitial Pneumonia 

MDD – Multidisciplinary Discussion 

NSIP – Nonspecific Interstitial Pneumonia 

OP – Organizing Pneumonia 

PFTs – Pulmonary Function Tests 

SARDs – Systemic Autoimmune Rheumatic Diseases 

UIP – Usual Interstitial Pneumonia 

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