Chest Flashcards
what is mosaicism
Mosaicism is defined as patchy difference in attenuation of the lung parenchyma. The crucial factor is the amount of air that is found in each voxel.
what is interstitial thickening?
infiltration of the interstitium by inflammatory tissue, fibrous tissue, cellular infiltrates or fluid, expand the interstium dispacing air from the voxel and increasing the density of the voxel.
what is air space filling?
partial filling of the air spaces with either cells, blood or fluid, displaces air, causing an increase in voxel density. Complete filling of the air spaces leads to consolidation which is not a component of mosaicism.
what is vascular constriction?
vascular constriction, secondary to small airways disease or pulmonary embolic disease, results in a reduction of size of the intralobular interstitium, causing an increase in the amount of air within the voxel. As a result, the density of the voxel decreases.
First question to riase when seeing mosaicism?
is it due to increased or decreased lung density?
how are mosaicism and GGO related?
GGO is a type of mosaicism from high attenuation lung.
How to differentiate types of GGO.
Interstital infiltrate
Partial air space filling
overferfusion
No change to vessels
No change to vessels
Minor increase to vascularity
With lower attenuation lung - work out the difference from
emphysema
pulmonary emboli
small airways disease
emphysema - blood vessels destroyed with lung
PE - vessels attenuated to no flow
Airway disease - reflex vasoconstriction
Why is it important on mosaicism to review the blood vessles of lung parenchyma
if blood vessels are present in normal amounts then you know the parenchyma is more opacified. GGO
if blood vessels are absent in the darker areas then you know it is the darker areas that have lower blood and more likely low attenuation mosaicism and so small airways disease
why does emphysema cause low attenuation of the lung?
due to destruction of lung tissue. As a result there are fewer vessels.
how to differentiate emphysema from small airways disease?
vascular pattern in emphysema becomes disorganised
small airways disease retains a branching pattern but is less obvious
features of a secondary pulmonary lobule?
2-3cm
supplied by a single bronchiole
central artery
venous drainage accumulate in the septa (edges)
what is crazy paving associated with? How sure are we of the association?
associated with alveolar proteinosis
but it is a non specific sign
what happens in the lung during alveolar proteinosis to cause the crazy pave pattern?
proteinacous fluid accumulates in the air spaces and interstitium causing geometric areas of higher attenuation lung (the paving stones - shaded on the image) interspersed with thickened inter and intralobular septa (the gaps between the paving stones - the lines on the image)
other causes of crazy paving pattern?
anything that causes GGO and thickened septa
eg. heart failure, lymphangitis carcinomatosa and non-specific interstitial pneumonitis
what does tree in bud describe?
endobronchial pathology on CT. Multiple centrilobular nodules are seen in a linear branching pattern
how many acini to a secondary lobule?
4 - 8
how big are acini?
6 - 10mm
what do the linterlobular septa contain?
lymphatics
connective tissue
septal veins
Interlobular septal thickening is seen in what conditions?
Lymphagnitis carcinomatosis
pulmonary oedema
aleveolar proteinosis
lipoid pneumoniasarcoidosis
asbestosis
pneumoconiosis
fibrosing alveolitis
how can setpal thickening be characterised?IST
smooth
irregular
modular / beaded
There is a background of fine scattered granuloma nodules. Beading along the oblique fissure is seen (Fig 1a) and is typical of the perifissural distribution, irregualar pattern of IST seen in ……..
sarcoid.
Pulmonary alveolar proteinosis is a rare condition in which…..
the alveoli fill with a lipid rich, periodic acid-Schiff (PAS) positive proteinaceous fluid. The lung interstitium itself remains relatively normal
Lymphangitis carcinomatosis refers to the spread of tumour through the lymphatic system within the lungs. It most commonly occurs in
adenocarcinoma
treein bud should make you think of what?
small airways disease
accumulation of mucus / secretions
how to distinguish tree in bud from normal arteriole?
larger than arteriole, doesn’t taper, irregular appearance. Patchy areas
which infections can cause bronchiolitis?
viruses, especially mycoplasma in children and adults alike, or haemophilus influenzae, atypical mycobacterium and fungi in adults
which infections calssically cause tree in bud?
TB and non tuberculous mycobacterium
What lies within the intersitital septum space?
a potential space with the pulmonary veins
where are interstitial tissues found?
peribronchovascular (hila)
centrilobular (within the pulmonary lobule)
subpleural (periphery of the lung)
interlobular
intralobular
why is knowing about different interstitial tissues important?
leads to diagnosis
What are the four main patterns of pathology to look for on thin section CT?
Reticular opacities
Nodular opacities
Increased lung density
Reduced lung density
Reticular opacities are also called what?
linear opacities
what conditions can cause interstitial septal thickening?
carcinomatosa lymphangitis.
interstitial fibrosis
alveolar proteinosis
interstitial pulmonary oedema
What are the three types of nodular opacity pattern in the lung?
Centrilobular distribution
Perilymphatic distribution
Random distribution
with a nodular opacity in a centrilobular distribution can get tree in bud. Why?
Centrilobular beonchiole - plugged with material due to inflammation from infection (TB/bronchiolitis)
Centrilobular nodular opacity pattern happens because of what relating to the anatomy?
centrally there is artery and bronchiole. usually pathology of the bronchiole causing inflammation
Perlymphatic distribution of norular opacities exist becuase of what anatomy?
seen in relatin to the lymphatic vessels. Nodules along the bronchovascular bundles, centre of the lobule, septa and the subpleural interstitium.
Seen along the fissues.
Perilymphatic nodular appearance seen in what ocnditions?
Sarcoidois and silicosis
Random distribution of nodular opacities? Seen where and why?
blood borne disease like miliar metastases. Have no relatin to the lobule anatomy.
What are two forms of increased lung density?
Ground glass and consolidation
Ground glass vs consolidation?
partial filling vs full fillling of air space. Ground glass can also be interstitium.
What are the main conditions considered for low lung density?
emphysema, small airways disease, Langerhand cell histiocytosis, lymphangioleiomyomatosis (LAM) and bronchiectasis.
What is centrilobular emphysema closely related to and why?
smoking. Earliest changes occur adjacent to bronchiole at the centre of the pulmonary lobule and go outwards
What is panlobular emphysema assocaited with?
alpha 1 antitrypsin deficiency
What are the features of panlobular emphysema?
extensive areas of low density in the lung bases.
Low density lungs - small airway disease happens how?
Results in difficulty emptying the alveolae resulting in poor gas exchange
low oxygen tension which in turn leads to reflex vasoconstriction
a reduction in perfusion. The combination of retained air and reduced perfusion causes a decrease in lung parenchymal density
crazy paving pattern is associated with?
alveolar proteinosis but also lipoid pneumonia. Smoking related ILD
hilar point is the point where…..
the lateral margin of the superior pulmonary vein crosses the lateral margin of the basal pulmonary artery:
Two groups of asbesotos?
Amphiboles -crocidolite dangerous - straight needles
Serpentines - curved needles
How does crocidolite cause mesothelioma?
Fragment, deposit in the small airways and airspaces. Get into the lung interstitum and cause the inflammation / fibrosis.
Which conditions are assocaited with asbesotos BENIGN
Pleural plaques
Pleural effusion
Diffuse pleural thickening
Folded lung/round atelectasis
Interstitial lung fibrosis - asbestosis
How to differentiate pleural plaque from thickened pleura?
Well defined lateral edge for plaque
What is the earliest asbestos related sign that may be seen?
Pleural effusion
Diffuse pleural thickening is said to exist when ….
a smooth uninterrupted layer of thickened pleura extends over at least one quarter of the chest wall
How to differentiate diffuse pleural thickening from mesothelioma?
In DPT there should not be anything on the mediastinum
Causes of pleural thickening?
Post TB empyema, haemothroax, asbestos exposure
What is folded lung?
Same as round atelectasis. collapsed lung party surrounded by thickened visceral pleura - forms a mass.
CT appearance of folded lung?
Whirpool appearance of vessels and bronchi drawn in
Volume loss.
Abestos ILD pattern
Reticular shadowing at the lung bases extending upwards
Sub-pleural small round or branching opacities are seen in what conditions?
earliest changes seen in ILF interstitial change, lying a few millimetres from thepleura and they represent peri-bronchiolar fibrosis.
What are Sub-pleural curvilinear opacities
lie parallel to the chest wall in the lower zones. They may be seen in early disease, but can represent plaque related atelectasis, or be associated with honeycomb change in more advanced disease.
What are parenchymal bands?
linear opacities between 2 and 5 cm in length running through the lung, often ‘joining’ an area of pleural thickening. They represent thickened fibrotic interlobular septa, and are associated with distortion of lung parenchyma. They are more common in asbestosis than in any other form of pulmonary fibrosis.
Pneumoconiosis is caused by the
inhalation and deposition of fine particles of inorganic dust in the lungs
inhaled dust may be classified as
non-fibrogenic or fibrogenic, depending on how the body reacts to the inhaled particles
Pneumoconiosis can also be classified as simple or complicated. Depedning on….
This has nothing to do with the type of dust involved, but depends on whether or not pulmonary massive fibrosis (PMF) is present
Non-fibrogenic dust are what
biologically inert, causing minimal fibrosis in the lungs and very few clinical symptoms. Examples include:
Iron oxide causing siderosis
Barium sulphate causing baritosis
Tin oxide causing stannosis
fibrogenic dust are what
Coal dust (coal worker’s pneumoconiosis (CWP))
Silica (silicosis)
Asbestos (which is a silicate) – see session in Module 1b Thoracic-Respiratory/Benign Asbestos Related Disease (300-0045)
Beryllium (berylliosis)
Talc (talcosis)
Pure coal dust causes very little fibrous reaction - why does it cause issues?
but it is often contaminated with silica and is therefore classified with the fibrogenic dusts. Pulmonary massive fibrosis (PMF) is also seen in CWP.
simple pneumoconiosis findings
Characteristic pathological finding is the coal macule which is a deposit of coal pigment in lung parenchyma, 1 to 5 mm in size, without any associated fibrosis
Pulmonary massive fibrosis (PMF) occurs in CWP is defined as what?
area of fibrosis containing coal pigment exceeding 1 cm in diameter. PMF opacities can be very large, and when present, the term complicated pneumoconiosis is used.
e characteristic chest radiograph finding in simple CWP is
multiple small round opacities, 1-5 mm diameter, in the upper and mid zones. Hilar lymph node enlargement occurs in up to 30% of cases and the nodes are usually calcified (although the eggshell pattern of calcification seen in silicosis is uncommon).
PMF mass migrates centrally towards the hilum, leaving WHAT KIND OF EFFECT ON THE LUNG
emphysematous lung between the mass and the chest wall.
how to speerate PMF from a lung cancer?
PMF should have background lung nodularity
PMF is seen as
PMF develops as a peripheral mass greater than 1cm in diameter with a well-defined lateral border.
What is Caplans syndrome?
a manifestation of rheumatoid lung disease and is more commonly seen in CWP than silicosis. Large nodules that are necrobiotic
What are the two diseases from exposure to silica dust?
Classic silicosis
Silicoproteinosis
What is classic silicosis
This is caused by relatively low exposure to silica dust over a prolonged period of time, resulting in pulmonary nodules and fibrosis (simple silicosis).
silicotic nodule - dense concentric layers of collagen.
What is silicoproteinosis
exposed to high concentrations of silica dust particles over a relatively short period of time, e.g. sand blasters.
d eggshell calcification of hilar nodes is virtually pathognomic of
silicosis.
CWP apperance is similar to silicoproteinosis or silicosis?
Silicosis. Similar pathology type of filling thealveoli and nodules
CT features of silicoproteinosis vs silicosis?
silicoproteinosis CT appearances consist of bilateral centrilobular ground glass nodules, multi focal ground glass opacities and areas of consolidation. On high resolution CT thickening of the interlobular, septae may be seen as a crazy paving pattern.
Silicosis small, sharply defined nodules, typically perilymphatic in location, scattered throughout the upper and mid zones of the lungs.
signs of TB in silicoprteinosis
cavitation with PMF
rapid progression of lung changes
Siderosis is a condition caused by inhalation of
iron oxide particles.
Siderosis chest xr signs?
reticulo nodular opacities
Stannosis caused by?
Tin
Benign but striking chest radiograph
UIP is also called
Idiopathic pulmonary fibrosis
UIP is the histopathological diagnosis - but similar path appearance to
Collagen Vascular disease
Drug toxicicty
Chronic hypersensitivity pneumonias
IPF is common in what demographics?
males, 40 - 70 . rare in kids
Increased risk of what in IPF?
Bronchogenic carcinoma (x7(
Right heart failure
histological hallmark of UIP is a
heterogeneous involvement of lung tissue with alternating areas of normal lung, interstitial inflammation, fibrosis and honeycombing
IPF appearance on CT?
subpleural bibasal reticular pattern.
Cystic air spaces (honeycomb destruction)
lymphadenopathy
Mid zone predominance, starts in the lung bases
Non specific interstitial pneumonias (NSIP) - what is it?
inflammatory and fibrosing process going on.