1. Radiology of Connective Tissue Disease associated Interstitial Lung Disease
John Murchison

2. Why do HRCT?
Superior to CXR and conventional CT at showing parenchymal abnormalities
With MDCT all CT chests are effectively HRCT

3. Indications for HRCT Is lung disease present?
What is the nature of the abnormality?
Are changes acute or chronic?
Follow up to assist management
Selection of biopsy site

4. Indications for HRCT Is lung disease present?
Much more sensitive at assessing lung parenchma than CXR
Superimposed structures
? Normal ? Abnormal
PFT abnormalities and apparently normal CXR
Is further management required?
Or no need eg emphysema

5. Indications for HRCT What is the nature of the abnormality?
Sometimes able to give a specific diagnosis
Bronchiectasis, UIP, emphysema
Narrows the differential diagnosis
Appropriate selection of further tests

6. Indications for HRCT Are changes acute or chronic?
Chronic eg fibrosis
Acute ground glass
Follow up to assist management
Has disease progressed / improved?
Selection of biopsy site
Many diffuse lung diseases have a patchy distribution. Select active disease
Avoid end stage fibrosis

7. Scanning Variants
Supine scan- standard
Prone scan
Expiratory scan

8. Scanning Variants Prone scan- supine
dependant changes often seen particularly at lung bases
If concern that may be obscuring early fibrosis or that changes may not be genuine do prone scan
prone

9. Scanning Variants Prone scan- supine
dependant changes often seen particularly at lung bases
If concern that may be obscuring early fibrosis or that changes may not be genuine do prone scan
prone

10. Scanning Variants Inspiration Expiratory scan Expiration
Demonstrates air trapping
If concern re obstructive lung disease eg PFTs
Hyperlucency on HRCT
If particularly looking for conditions where air trapping likely eg Bronchiolitis obliterans
In normal patients HU increases uniformly on expiration
If air trapping HU remains low
Expiration

11. Patterns of air space opacification
consolidation
ground glass

12. Ground Glass ground glass attenuation
Ground glass attenuation may be correlate with
a) evidence of interstitial inflammation with airspace filling by macrophages
b)patchy fibrosis or
c) a combination of above.

13. HRCT features of fibrosis,
Intra-lobular and inter-lobular septal thickening, walled cysts representing honeycombing,
may be associated traction bronchiectasis

14. DPLD IPF / CFA NSIP COP AIP RB-ILD DIP LIP
Diseases of known cause
or association
Granulomatous diseases
Idiopathic interstitial pneumonias
Others
Connective tissue diseases
Drug-induced diseases
Asbestosis
Pneumoconiosis
Sarcoidosis
UIP
NSIP
AIP
LIP
COP
RB-ILD
DIP
Eosinophilic
diseases
Rare diseases
IPF / CFA
Hypersensitivity pneumonitis

15. CXR-UIP
Initially ill-defined or ground-glass opacities, peripheral reticular opacities,
As disease progresses reticular pattern becomes coarser, most marked at bases, often volume loss, end stage diffuse honeycombing.

16. HRCT
1) features of fibrosis, Intralobular septal thickening, walled cysts representing honeycombing, may be associated traction bronchiectasis
2)ground glass attenuation common but usually less than reticular abnormalities. Ground glass attenuation may be correlate with a) evidence of interstitial inflammation with airspace filling by macrophages b)patchy fibrosis or c) a combination of above.
3)characteristically a peripheral basal distribution

17. Radiological differential diagnosis in ‘IPF’
An HRCT that predominantly shows bibasal honeycombing is virtually 100% specific for UIP.
The HRCT pattern of UIP found in IPF can be indistinguishable from that seen in asbestosis, collagen vascular disease or as a response to drugs.
Patients with chronic hypersensitivity pneumonitis or with end-stage sarcoidosis can uncommonly develop a CT pattern similar to UIP
IPF
Drugs
CTD
Asbestosis
Sarcoid
EAA
UIP
NSIP
DIP RBILD
COP

18. CXR NSIP
bilateral pulmonary infiltrates. Lower lung zones more frequently involved.

19. HRCT NSIP
1) ground glass predominant finding in most cases and sole finding ~50%.
2) Irregular linear or reticular opacities seen about 50% cases. May be traction bronchiectasis.
3) Honeycombing and consolidation relatively infrequent
4) Bilateral symmetrical basal predominance

20. NSIP radiological differential diagnosis
Depends on the predominant pattern exhibited.
Experienced radiologist found it indistinguishable from
UIP 32%
Hypersensitivity pneumonitis 20%
Organising pneumonia 14%
Other diagnosis 12% Radiology 2000 vol 217

21. Extent and Distribution of disease UIP /NSIP
Feature NSIP UIP p value
Disease extent (%) / /
Ground glass (%) / / <.005
Coarseness score (max 15) / /
Subpleural distribution (%)
Basal distribution (%)
Bronchocentric distribution
53 patients
Macdonald et al Radiology 2001: 221

22. COP radiology
Patchy non-segmental, unilateral or bilateral areas of air space consolidation.
Often vary in site and configuration over time.
May be irregular reticular opacities. Rarely a major feature.
Small nodular opacities usually with other features but occasionally on their own

23. COP HRCT findings 1 Bilateral Air-space Consolidation 80%
2 Ground glass opacities 60%
3 Subpleural and/or peribronchovascular distribution
4 Bronchial wall thickening, dilatation in abnormal areas
5 Small nodular opacities often peribronchiolar (30-50% of cases)
6 May get irregular reticular opacities
7 Combination of findings in 1 and 2

25. COP pre and post treatment

26. HRCT Rheumatoid Arthritis
HRCT patterns
UIP/ NSIP
COP
Brochiolitis obliterans
Necrobiotic nodules
Pleural thickening/ effusions

27. Scleroderma.(PSS) High prevalence of pulmonary involvement
HRCT patterns
Pulmonary arterial hypertension( 50%)
ILD ( 80%) usually NSIP
Pleural thickening /effusion
Oesophageal dilatation.

28. CXR and CT clues
Joint abnormalities particularly AC and shoulder joints with Rheumatoid arthritis
Dilated oesophagus suggest scleroderma or variant
Pulmonary artery enlargement out of proportion to lung parenchymal changes may reflect vaculopathy especially scleoderma
Soft tissue calcification –dermatomosytis or scleroderma
Multiple compartments think RA

29. Radiology of Idiopathic ILD
The lung has a limited number of patterns of response to injury and there is often a lack of correlation between aetiological insult and radiological appearance of the lung
We need to recognise that in many cases there is not a clear cut match between the ‘clinical syndrome’ and the ‘radiological pattern’ of disease
The latter may be more important in determining prognosis
Patients are managed in a multi-disciplinary manner in order to reach a final clinical diagnosis

30. Drug treatment
Gold usually diffuse alveolar infiltrates- can look like OP
Methotrexate-
can produce sub-acute hypersensitivity- centilobular ground glass
Pneumonitis –more likely if pre-existing ild
D-penacillamine- constrictive bronchiolitis
Non -steroidals – hypersensitivity
Salicylates OD pulmonary oedema
Opportunist infections
Increased risk lymphoma and lung cancer