Narrow slice thickness (1 mm) at 10 mm intervals.
Image reconstruction with high spatial resolution.
Generally end inspiration views are taken.
One can also take expiration , prone views when
A window width of 1300 , window level of -6oo HU
No IV injection of contrast is used.
- caused by thickened interlobular or intralobular
- infiltration by fibrosis, abnormal cells, or fluid.
- Interlobular septal thickening is usually
described as smooth OR irregular.
- manifests as a fine reticular pattern on HRCT.
- Late stage – honeycombing, characterized by
cystic airspaces surrounded by irregular walls.
- feature of both interstitial and airspace disease.
- Perilymphatic nodules within the lung
interstitium, especially those related to the
lymphatic vessels, are seen in the interlobular
septa, subpleural and peribronchovascular
- Centriacinar nodules
Centriacinar nodules in a
patient with subacute
Perilymphatic and Random distribution of nodules ,
seen in sarcoidosis.
- is defined as a generalized increase in opacity
that does not obscure pulmonary vessels.
- include partial filling of the airspaces,
considerable thickening of the interstitium, or a
combination of the two.
obscuration of vessels.
- Resolving pulmonary
- refers to regional attenuation differences
demonstrated on HRCT.
- depends on the amount of blood, parenchymal
tissue and air in that area.
- small airways disease, occlusive vascular
disease and infiltrative lung disease.
Mosaic pattern due to air trapping/altered perfusion
This is a clinical , radiological , pathological
– Exclusion of known causes such as exposure, drugs etc
- Abnormal pulmonary function tests with restrictive pattern
- HRCT findings
- Transbronchial lung biopsy or BAL
- Age > 50 years
- Insidious onset of dyspnea on exertion
- Duration of illness >3 months
- Bibasilar inspiratory crackles
The number of fibroblastic foci on lung biopsy is
an important predictor of survival.
Classic chest radiographic features include
bilateral asymmetric peripheral reticular opacities
most profuse at the lung bases associated with
lung volume loss.
As the disease progresses, it often appears to
‘creep’ around the periphery of the lung to
involve the anterior aspects of the upper lobes.
The rapid development of a diffuse increase in
the attenuation of lung parenchyma in patients
with IPF should raise the possibility of an
Usual interstitial pneumonia. HRCT abnormalities predominate in the
posterior, subpleural regions of the lower lobes and comprise
honeycombing and traction bronchiectasis within the abnormal lung.
Coarse reticular opacities, subpleural honeycombing and
(A) before and (B)
deterioration in a
of the disease
increase in lung
both the reticular
NSIP is characterized by varying degrees of
interstitial inflammation and fibrosis without
the specific features that allow a diagnosis of
UIP or DIP.
NSIP may have significant fibrosis, it is usually
of uniform temporality (in comparison to UIP).
On HRCT, NSIP is characterized by a
predominant pattern of ground-glass
opacification in a predominantly basal and
subpleural distribution with or without
associated distortion of airways.
A reticular pattern is common but
honeycombing is sparse or absent.
NSIP may be distinguished from UIP on CT
by a more prominent component of ground-
glass attenuation and a finer reticular pattern
in the absence of honeycombing.
Non-specific interstitial pneumonia. The predominant abnormality is
patchy, bilateral ground-glass opacification, mild reticulation and
traction bronchiectasis. There is no frank honeycombing destruction.
is identifiable in a variety of different contexts,
including infection, malignancy, drug-related
On a chest radiograph the most frequent
feature of COP is patchy, often subpleural and
basal, areas of consolidation with preservation
of lung volumes.
The areas of airspace consolidation have a
propensity to progress and change location
On HRCT, consolidation corresponding to
areas of organizing pneumonia is the cardinal
feature found more frequently in the lower
zones, with either a subpleural or a
Ground-glass opacification, subpleural linear
opacities and a distinctive perilobular
The histopathological appearance of
organizing pneumonia is a uniform temporal
appearance of mild interstitial chronic
inflammation associated with an intraluminal
organizing fibrosis in distal airspaces.
Cryptogenic organizing pneumonia. HRCT through the upper lobes demonstrates
areas of consolidation in a subpleural and peribronchial distribution in association
with areas of ground-glass opacification (left upper lobe).
strong association with cigarette smoking
insiduous onset of dyspnoea and cough.
chest radiograph is relatively insensitive
On HRCT,in RB–ILD = areas of patchy ground-
glass opacification (resulting from macrophage
accumulation within alveolar spaces and
and poorly defined low attenuation
centrilobular nodules .
In addition, upper lobe centrilobular
DIP = Ground-glass opacification is typically
lower zone, peripheral and may be patchy.
Some features of interstitial fibrosis may be
Smoking cessation is an important part of the
global term smoking related-interstitial lung
disease (SR-ILD) has been proposed
Respiratory bronchiolitis–interstitial lung disease.
HRCT shows (A) subtle areas of ground-glass
opacification and (B) ill-defined centrilobular
Several areas of non-specific ground-glass opacification in
the right middle lobe and both lower lobes
idiopathic form of the ARDS
histological pattern seen in AIP is that of
diffuse alveolar damage (DAD), which is also
found in infection, connective tissue disease,
drug toxicity, toxic inhalation, uraemia and
DAD has an acute exudative phase and a
subsequent organizing and fibrotic phase.
diffuse involvement with temporal
chest radiograph shows bilateral patchy
HRCT demonstrates a combination of ground-
glass opacification, consolidation, bronchial
dilatation and architectural distortion.
characterized by a widespread interstitial
lymphoid infiltrate of the lung.
association with autoimmune diseases, most
often Sjögren's syndrome. Other diseases
include dysproteinaemias, autologous bone
marrow transplantation and viral,
mycobacterial and human immunodeficiency
virus (HIV) infections, Intrathoracic
Female > male
progressive cough and dyspnoea usually
HRCT findings are nodules of varying sizes,
areas of ground-glass opacification, thickened
bronchovascular bundles, interlobular septal
thickening and thin-walled cysts (1–30 mm).
The cysts in LIP are usually discrete, are not
found in clusters and are found deep within
the lung parenchyma.
Lymphocytic interstitial pneumonitis. There is a
background of ground-glass opacification and a few thin-
walled cystic airspaces.
is a granulomatous disorder characterized
histologically by the presence of large
histiocytes containing rod- or racket-shaped
male-to-female ratio is about 4:1, and the vast
majority of adult patients are cigarette smokers.
present with dyspnoea, cough, constitutional
symptoms or a spontaneous pneumothorax.
Pulmonary involvement is widespread,
bilateral and usually symmetrical.
Typical appearances are of reticulonodular
shadowing in the mid and upper zones of the
lungs that are of normal or increased volume.
The nodules vary in size from micronodular to
approximately 1 cm in diameter and, although
histopathological examination will often
On HRCT are nodules (ranges from a few mm
to 2 cm), several of which show cavitation (this
feature often clinches the diagnosis) and have
Langerhans cell histiocytosis. (A) Shows the characteristic
combination of thin-walled cysts and poorly defined
nodules, some of which are just beginning to cavitate. (B)
Image from a patient with more advanced disease. There
are numerous irregularly-shaped cysts bilaterally and a
pneumothorax on the right.
characterized histologically by two key
features: cysts and proliferation of atypical
smooth muscle cells (LAM cells) of the
pulmonary interstitium, particularly in the
bronchioles, pulmonary vessels and
LAM is a rare disease seen almost exclusively
approximately 1% of patients with tuberous
pattern of generalized, symmetrical, reticular,
or reticulonodular opacities with normal or
increased lung volumes.
Pleural effusions occur in 10–40% of patients
and pneumothoraces in approximately 50% of
cases. The effusions are chylous and result
from involvement of the thoracic duct by the
characterized by numerous thin-walled cysts
randomly distributed throughout the lungs
with no zonal predilection.
Imaging features that help distinguish LAM
from LCH include a more diffuse distribution
of cysts typically with no sparing of the bases,
more regularly shaped cysts and normal
intervening lung parenchyma.
Lymphangioleiomyomatosis. (A) There is a profusion
of thin-walled cystic airspaces scattered evenly
throughout the lungs. The cysts are relatively
uniform in size. (B) In a more advanced case of LAM,
note the small left-sided pleural effusion.
65 year old male with progressive
Chest Xray shows prominent bronchovascular