HRCT in Diffuse Lung Diseases - II

Dr. Bhavin JankhariaJankharia Imaging

The key to learning HRCT interpretation in interstitial lung

diseases is to learn how to identify honeycombing, which allows us to

recognize the Usual Interstitial Pneumonia (UIP) pattern

Honeycombing – layered peripheral cysts, stacked one on top of the other

D/D of Honeycombing

BronchiectasisHoneycombing

Bronchiectasis presents with branching cystic and tubular areas

extending from the hilum to the periphery

EmphysemaHoneycombing

Emphysema presents with centrilobular cystic areas without

walls

Cystic lung disease

Honeycombing

Cystic interstitial lung disease presents with cysts with walls

randomly distributed throughout the lung parenchyma

The presence of honeycombing allows us to confidently make a diagnosis of a usual interstitial

pneumonia pattern (UIP)

Reticular pattern - honeycombingReticular pattern – no honeycombing

The absence of honeycombing as seen on the left image does not

rule out a UIP pattern, but a diagnosis of UIP cannot be made with any specificity in that context.

A non-specific interstitial pneumonia with fibrosis (NSIP) pattern also then comes into the

differential diagnosis

The Diagnosis of a UIP Pattern

IPF

UIP Criteria

Reticular abnormality

Honeycombing with or without traction bronchiectasis

Subpleural basal predominance

Absence of other signs like ground glass, nodules, etc

New IPF criteria – ATS/ERS

IPF

UIP Criteria

•Reticular abnormality

•Honeycombing with or without traction bronchiectasis

•Subpleural basal predominance

•Absence of features inconsistent with these

New IPF criteria – ATS/ERS

Upper zone - chronic hypersensitivity pneumonitis

Lower zone – UIP pattern

Long standing sarcoidosis with fibrosis – upper and mid-zone fibrosis

Upper zone predominance of honeycombing usually implies

chronic hypersensitivity pneumonitis or long standng parenchymal sarcoidosis with

fibrosis

IPF

UIP Criteria

Reticular abnormality

Honeycombing with or without traction bronchiectasis

Subpleural basal predominance

Absence of other signs like ground glass, nodules, etc

New IPF criteria – ATS/ERS

If all these criteria are met, then we can confidently make the

diagnosis of a UIP pattern

New IPF criteria – ATS/ERS

This is the new algorithm to make a diagnosis of Idiopathic Pulmonary Fibrosis (IPF)

In the presence of a UIP pattern, in the absence of an identifiable cause (e.g. rheumatoid arthritis, familial, etc), the presence of a

UIP pattern implies IPF

IPF

Issues• Complications – neoplasm, infection

IPF with superimposed opacity in the left lower lobe – TB on biopsy

IPF with progressive consolidation over a year – invasive mucinous adenocarcinoma on biopsy

Patients with IPF have an increased incidence of

superimposed infection and neoplasm. The HRCTs of patients

of IPF on follow-up should be examined for superimposed / new

pathology

IPF

Issues• Complications – neoplasm, infection• Combined emphysema with fibrosis (CPFE)

This patient has both emphysema in the upper lobes and a UIP pattern in the lower lobes

This occurs in smokers, with emphysema in the upper lobes

and IPF in the lower lobes. It has a worse prognosis than IPF and clinically can be a challenge to

diagnose

The next presentation will be on NSIP and other idiopathic

interstitial pneumonias

Thank You