Radiology of
Connective Tissue
Disease associated
Interstitial Lung
Disease
John Murchison
Why do HRCT?
• Superior to CXR and conventional CT at
showing parenchymal abnormalities
• With MDCT all CT chests are effectively
HRCT
Indications for HRCT
•
•
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•
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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
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
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
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
Scanning Variants
• Supine scan- standard
• Prone scan
• Expiratory scan
Scanning Variants
supine
• Prone scan– 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
Scanning Variants
supine
• Prone scan– 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
Scanning Variants
• Expiratory scan
Inspiration
– 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
Patterns of air space opacification
consolidation
ground glass
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.
HRCT
features of fibrosis,
Intra-lobular and inter-lobular
septal thickening, walled cysts
representing honeycombing,
may be associated traction
bronchiectasis
DPLD
Diseases of
known cause
or association
Connective
tissue
diseases
Granulomatous
diseases
Sarcoidosis
Idiopathic
interstitial
pneumonias
IPF / CFA
Others
UIP
Eosinophilic
diseases
NSIP
Drug-induced
diseases
Pneumoconiosis
COP
AIP
RB-ILD
DIP
Asbestosis
LIP
Hypersensitivity pneumonitis
Rare diseases
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.
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
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
Sarcoid
Asbestosis
EAA
Drugs
IPF
UIP
CTD
NSIP
DIP
RBILD
COP
CXR NSIP
bilateral
pulmonary
infiltrates. Lower
lung zones more
frequently
involved.
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
NSIP radiological differential
diagnosis
• Depends on the predominant pattern exhibited.
• Experienced radiologist found it indistinguishable from
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UIP 32%
Hypersensitivity pneumonitis 20%
Organising pneumonia 14%
Other diagnosis 12%
Radiology 2000 vol 217
Extent and Distribution of disease UIP /NSIP
• Feature
•
•
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NSIP
Disease extent (%)
37.1 +/- 22.7
Ground glass (%)
47.4 +/- 27.2
Coarseness score (max 15) 6.0 +/- 3.1
Subpleural distribution (%) 60
Basal distribution (%)
62
Bronchocentric distribution 5
UIP p value
44.0 +/- 23
26.7+/- 22.5
8.3+/- 2.9
71
70
9
.29
<.005
.01
.08
.25
.29
53 patients
Macdonald et al Radiology 2001: 221
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
COP
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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
COP pre and post treatment
HRCT Rheumatoid Arthritis
HRCT patterns
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UIP/ NSIP
COP
Brochiolitis obliterans
Necrobiotic nodules
Pleural thickening/ effusions
Scleroderma.(PSS)
• High prevalence of
pulmonary involvement
• HRCT patterns
– Pulmonary arterial
hypertension( 50%)
– ILD ( 80%) usually NSIP
– Pleural thickening
/effusion
– Oesophageal dilatation.
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
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
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
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D-penacillamine- constrictive bronchiolitis
Non -steroidals – hypersensitivity
Salicylates OD pulmonary oedema
Opportunist infections
Increased risk lymphoma and lung cancer