RESPIRATORY SYSTEM REVISION NOTES

Radiology chest
TONY SCARIA 2010 KMC

X ray as modality in chest

AP
• Detect minimum of 150 -200 ml
fluid

Lateral projection(RL projection)

All major fissures are clearly visible in lateral
view

Lordotic view
• Best view to assess apex & middle lobe
of lungs & lingular pathologies

Reverse lordotic view
• To assess interlobar effusion

Anterior oblique view of lung
Both these views are used for coronary angiography
Right anterior oblique view • Demonstrates maximum area of left lung field
• Assessment of pulmonary A RV & size of left atrium
Left anterior oblique view • Demonstartes maximum area of right lung
• Assessment of left & right ventricles left atrium &
aortic window & aorta

Inspiratory film • > 6 anterior ribs or
• > 10 posterior ribs
Expiratory film • <4 anterior ribs

Normal chest x ray erect film
• Pulmonary vessels supplying upper lung fields & less in number than
supplying lung bases
• Upper lobe vessels
• <3 mm in diameter
• <3 in number

Artery : bronchus ratio
Ratio
Upper lobe (vessels in upper lobe are smaller than
accompanying bronchus)
0.85
Hilum 1
Lower lobe (larger in lower lobes) 1.35

Rt heart border
• SVC
• RA
• IVC
• Ascending aorta (in elderly)

Lt heart border
• Aortic arch
• Aortopulmonary window
• Pulmonart trunk
• Left auricle
• Left ventricle

Hilum
• Upper lobe pulmonary V
• Descending pulmonary A
• Lymphatics
• Bronchi

Left is at a
higher angle
than right

Left dome is below right dome

FILM focus distance in case of CXR is 180 cm
(72 inches)

Rib notching
• Inferior rib notching more
common than superior
• Inferior is mainly d/t vascular
causes

Rib notching
Superior rib notching Inferior rib notching
• P POLIO
• O OSTEOGENESIS IMPERFECTA
• R RESTRICTIVE LUNG DISEASE
• N NEUROFIBROMATOSIS
• M MARFANS SYNDROME
• C CONNECTIVE TISSUE DISEAS E
• H HYPERPARATHYROIDISM
• C COARCTATION OF AORTA
• P PULMONARY OLIGEMIA
• A AORTIC THROMBOSIS
• S SUBCLAVIAN OBSTRUCTION
• T TAUSIG BLALOCK OBSTRUCTION

Inferior rib notching

Pulmonary embolism

Initial investigation D dimer
Initial radiological investigation Chest x ray
2nd imaging after normal or equivocal CXR Ventilation perfusion scan
Best investigation / investigation of choice MDCT with pulmonary angiography
Gold standard Invasive catheter pulmonary angiography
IOC in pregnant female Ventilation perfusion scan

CXR features of PTE
Fleischers sign Dilated central pulmonary A
Westermark sign Focal area of oligemia of lung seen as radioluscent
area
Hamptons hump Triangular area of peripheral wedge shaped opacity
Palla s sign Dilated right descending pulmonary artery
Knuckle / chang sign Dilated right descending pulmonary A with abrupt
changes in calibre of distal pulmonary A
Felsons sign Pleural effusion(left >right)
Flesishners line Long curvilinear line reaching pleural surface
RV enlargement

Pulmonary embolism
• Hamptons hump
• Westermark sign
• Fleischner sign

Hamptons hump
• Wedge shaped infiltrate
• Pleural based

Pallas sign
• Enlarged Right descending
pulmonary artery

• Asymptomatic in 70 %
• Chest pain
• Sudden onset Dyspnea
• Hemoptysis
• Most common cause of a/c RVF

Pulmonary embolism
• Most important cause of a/c RVF

RF
• Pregnancy
• Post partum
• Prolonged immobilisation
• Protein S deficiency
• Recent surgery
• AF

Pulmonary artery is blocked

Small pleural
effusion

ECG in PTE
• Sinus tachycardia (most common )
• S1Q3T3 characteristic

Ventilation perfusion scan
• 2nd MC frequent imaging investigation for suspected case of PTE after
a CXR
• Under perfused lung with normal ventilation
Perfusion Injecting Tc99m macroaggregate of
albumin
Ventilation Inhaling krypton (best )/ xe/

ECHO
• Mcconnels sign
• Apex of R ventricle contracts
• But free walls of R ventricle don’t contract

Diagnostic Algorithm

D dimer
• Fibrin degradation product
• Elevated D dimer (>500ng/ml) 
endogenous fibrinolytic process
• Done in patients high
probability of PE

Pulmonary Angiography in PE
The “gold standard”
 A negative pulmonary angiogram excludes clinically
relevant PE.
 The risk of embolization in patients with a negative
angiogram is extremely low

CT pulmonary angiography
• Best screening test
• Which show clots even after 5th branching
• It shows
• Saddle thrombus
• Polomint sign
• Railway track sign

Saddle shaped thrombus in CT angiography
Thrombus extending to
both right & left
pulmonary arteries

Polo mint sign

Railway track sign in pulmonary TE

Rx
• Heparin
• LMW heparin
• Oral warfarin
• IVC filter
• Secondary prevention
• In pts who develop embolism
despite heparanisation

sarcoidosis

Sarcoidosis
• Occurs in 30-40
• F>M
• PFT
• Restrictive pattern > obstructive pattern (endobronchial sarcoidosis )
• MC cause of mortality  irreversible lung fibrosis with respiratory
failure
• IOC HRCT lungs
• Gold standard  lung biopsy

CXR features of sarcoidosis
• 1,2,3 sign or Garland sign • triad of lymph node enlargement; right
paratracheal, right hilar and left hilar.
• 1,2,3,4 sign • b/l symmetrical hilar & right paratracheal LN +
aortopulmonary window nodes
Calcification Eggshell calicification

1,2,3 sign / garland sign

Siltzbach staging on CXR

b/l hilar lymphadenopathy in sarcoidosis

HRCT
• To detect subtle parenchymal
changes
• To differentiate inflammation
from fibrosis in stage 2& 3

PANDA sign in sarcoidosis
• When the normal accumulation of
the radionuclide in the nasopharynx
is combined with increased
symmetric accumulation in the
parotid and lacrimal glands, the
image shows a striking similarity to
the mottled coloring of the giant
panda.

Signs in sarcoidosis

On gallium scan (gallium is taken up by
lymphocytes)
Panda sign Lambda sign
• Uptake by b/l lacrimal parotid glands & normal
nasopharyngeal mucosa
• Uptake in b/l symmetrical hilar nodes & right
paratracheal nodes
Giant face of panda sign in MRI in a patient with
sarcoidosis
Lambda sign is also seen in dichorionic diamniotic twin on
USG

Egg shell calcification
• Pneumoconiosis
• Sarcoidosis
• Irradiated lymphoma

Galaxy sign in sarcoidosis in CT scan

Small satellite nodule at periphery of the
mass  galaxy sign

Pulmonary edema

Stage 1
• First equalisation of
vessels fb
prominence of
upper lobe vessels
• Stag antler sign or
Reverse moustache
sign
• Upper lobe vessels
>3mm in diameter
& 3 in number in 1st
ICS

Stag antlers sign

Increased artery to bronchus ration in CHF

Stage II
• Leakage of fluid in to peribronchial & interlobular interstitium
Kerley B lines Peribronchial cuffing Perihilar haze
• Fluid leak into
peripheral interlobular
septa
When fluid leaks into
peribronchial vessels
Loss of definition of these
vessels

Kerley B lines
Transverse non-branching 1-2
mm lines at the lung bases
perpendicular to
the pleura 1-3 cm long
Thickened interlobular septa

Perihilar haziness in a patient with CHF

Stage III alveolar edema
• Continued leakage of fluid in to
interstitium leads to leakge in
to alveoli (alveolar edema) & in
pleural cavity  pleural
effusion
• Alveolar edema  typical
perihilar  batwing
appearance

Vascular pedicle broadening in C/C CHF
Normal In a patient with CHF
Vascular pedicle >
8.5mm

Kerley's line
• A
• B
• C

Kerleys A line
• approximately 4 cm in length
• most conspicuous in the upper
and mid portions of the lung.
• deep septal lines (lymphatic
channels) that radiate from the
hila into the central portions of
the lungs
• do not reach the pleura
• In severe cardiac failure

Kerleys B line @ Base
• Horizontal
• At lung base
• shorter (1 cm or less) interlobular septal lines, found predominantly
in the lower zones peripherally, and parallel to each other but at right
angles to the pleural surface

Kerleys C line
• Spider web like
• Through out lungs

Causes of kerleys line
• Pulmonary edema d/t LVF
• MS

CXR in CHF

Pseudotumour in CHF

Pleural effusion

Investigations to detect pleural effusion
View Can detect in ml
Supine chest x ray 500 ml
CXR PA view 150- 200ml
Lateral chest x ray 75 ml
Lateral decubitus 10-25 ml
Most sensitive test to detect minimum pleural effusion  USG (< 15 mL)

Pleural effusion
• Obliterated CP angle
• Distinct margin
• Ellis curve  concave upward
margin

Phantom tumour /vanishing tumour
• Interlobar effusion disappears on diuretic
therapy

Empyema thoracis

• Pleural lesion makes an
obtuse angle with chest
wall
• Parenchymal lesion
makes an acute angle
with chest wall

Split pleura sign in empyema thoracis

Horizontal air fluid level in
hydropneumothorax

Pneumothorax

On M mode of USG
Normal lung Pneumothorax
Seashore sign Barcode sign / stratosphere sign
• IOC in pneumothorax  CT scan
• Best xray view  PA view in full expiration

Radiological Features of pneumothorax
• Deep sulcus sign
• Absent bronchovascular
markings
• Shift of mediastinum to
opposite direction in tension
pneumothorax
• Visceral pleural reflection
• No lung markings peripheral to
visceral pleural reflection

Deep sulcus sign in supine radiograph

pneumomediastinum

pneumomediastinum
Spinnaker sign / thymic sail sign / angel wing sign • In neonate
• Thymus being outlined by air with each lobe
displaced laterally & appearing like spinnaker sails
Continous diaphragm sign • Normally central portion of diaphragm is not
discretely visualised as it merges with cardiac
silhouette
• In pneumonediastinum it can be seen continuously
across midline
V sign of naclerio • V shaped air collection
• One limb of V is produced by mediastinal air
outlining the left lower lateral mediastinal border
• Other limb is produced by air b/w parietal pleural
& left hemidiaphragm

Spinnaker sign in pneumomediatinum

v sign of naclerio

Continous diaphragm sign

Collapse of lung

Luftsichel sign
• Left upper lobe collapse
• Radiographic appearance d/t
hyperinflation of superior segment of
left lower lobe interposing itself b/w
mediastinum & collapsed upper lobe

Luftsichel sign

Luftsichel sign  left upper lobe collapse
CT scan –> interposition of aerated lung b/w collapse
& mediastinum

Flat waist sign
• Severe left lower lobe collapse
• Left ward displacement & rotation of heart
flattening of contours of aortic arch &
pulmonary trunk

Flat waist sign

Golden S Sign
• In right upper lobe collapse
• By a mass obstructing upper lobe bronchus
• Suspect
• bronchogenic carcinoma
• Enlarged LN
• Metastasis

Industrial lung disease

Industrial lung disease
Upper lobe involvement Lower lobe involvement Diffuse lung involvement
• Silicosis
• Silicotuberculosis
• Coal workers pneumoconiosis
• Asbestosis • Stannosis
• Siderosis
• Barytosis
IOC  asbestosis

Asbestosis
• Initial radiological investigation  CXR
• IOC  asbestosis
Earliest imaging feature Specific imaging feature
• Fine reticular / nodular pattern in
lower zones
• Later  shaggy heart sign (loss of
clarity of heart & diaphragm)
• b/l calcified pleural placques on
diaphragm with sparing of CP angle

Other imaging features of asbestosis
Pleural effusion • Blood stained persistent recurrent
• b/l
• Small (<500ml)
Pleural placques • b/l
• Typically on parietal pleura
• Posterolateral & lateral chest wall from 6th to 10th
rib
• Visceral pleura / apex & CP angles are spared
Pleural calcification • b/l diaphragmatic calcification
Rounded atelectasis • Comet tail appearance/folded lung
• Pseudotumour appearance e
Malignancies • Mesothelioma

Shaggy heart sign

Pleural placques in asbestosis

Shaggy heart appearance also seen in
pertussis

Rounded atelectasis in asbestosis
• Rounded area of collapsed lung
• Peripheral lower posterior lobes
• Always adjacent to visceral pleura
• Adjacent to an area of focal pleural thickening or effusion

Crow feet sign in rounded atelectasis
• Comet tail appearance / crow feet sign /
vacuum cleaner sign/swiss cheese
airbronchogram sign
• Curving of bronchi & vessels at the margin
of collapsed lung like a tail pointing towards
hilum

Comet tail appearance in
asbestosis
• In rounded atelectasis of asbestosis
• produced by the pulling of
bronchovascular bundles giving the
shape of a comet tail

Silicosis
Simple silicosis Silicosis complicated with
• Small tiny pulmonary nodules in upper lobe
• Egg shell calcification
• Resembles coal workers pneumoconiosis
(progressive massive fibrosis )

Simple silicosis

Coal workers pneumoconiosis/ progressive
massive fibrosis
Peripheral
emphysematous bullae
Fibrosis spreading from
periphery to centre

Tuberculosis

Primary TB Progressive primary Post primary (reactivation)
• Initial infection by organism
• Heals by fibrosis & calcification
• No site predilection
• Ghons focus local infection
• Reinkes focus local infection +
LN
• Increase in primary infection • d/t reactivation of latent
primary infection
• MC site apical & posterior
segment of upper lobes &
superior segment of lower lobes
• Lobar consolidation  MC in
adults
• Atalectasis d/t
lymphadenopathy  MC in
children
• Increase in consolidation with
cavitation
• Consolidation cavitation
• Tree in bud appearance on HRCT

Tree in bud appearance in post primary TB

Miliary TB
• Hematogenous spread
of infection from a
pulmonary nidus
• In primary TB & post
primary TB
• Small 1-3mm nodules
randomly distributed in
both lung field

TB
Rasmussen aneurysm Pulmonary artery aneurysm in a TB cavity
Mc cause of hemoptysis Bronchial artery
First vessel to be investigated in hemoptysis Bronchial artery

Rasmussen aneurysm

Pneumonia

Air bronchogram sign

Air bronchogram sign
• Surrounding alveoli are opacified
& air in bronchi become visible as
linear branching structures(bcz of
air in bronchi)
Common causes Less common causes
• Consolidation
• Pulmonary edema
• HMD
• Alveolar carcinoma
• ARDS

Pneumatocele are seen in staphylococcal
pneumonia
• Also caused by pneumocystis
carinii

Pneuamtocele are also seen in
• Staphylococcus  MC
• Klebsiella
• Pneumocystis pneumonia
• Lung injury
• Kerosene poisoning

Klebsiella pneumonia

Klebsiella
In Klebsiella pneumoniae lung X-ray
finding shows cavitatory pneumonia
and bulghing fissure sign

bronchiectasis

Bronchiectasis
Signet ring sign Whendilated bronchus & accompanying pulmonary
artery branch are seen together in cross section
Tram track sign Lack of peripheral tapering of bronchus
String of beads appearance Varicose bronchiectasis  alternate dilation &
constriction
Cluster of grapes Cystic bronchiectasis
IOC in bronchiectasis is HRCT

Signet ring sign
• Signet ring sign in bronchiectasis
• Bronchi larger in size than
corresponding pulmonary artery

Honey comb appearance  severe
bronchiectasis

Honey comb appearance of lungs
• ILD
• RA
• Scleroderma ‘
• Tuberculosis

Aspergilloma

Aspergilloma Invasive aspergillosis Allergic bronchopulmonary
aspergillosis
Crescentic shadow /monod sign/air
crescent sign
• Halo sign (ground glass with
peripheral attenuation)
• Central bronchiectasis
• Upper lobe opacities
• Bronchocele (mucus filled)
• Finger in glove (tubular dilated)
• Reverse halo sign
• Cryptogenic organising
pneumonia
• Pulmonary
mucormycosis

Finger in glove sign

• HRCT scan revealed
extensive central cystic
bronchiectasis filled with
high density mucus
material involving right
upper lobe (finger in
glove appearance

Aspergilloma
• In c/c lung cavity
• Monod sign / crescent sign
• Aspergillus (fungal ball)with
in the lung cavity
• It shifts position on turning
the patient

Crescent / monod sign

Invasive aspergillosis
• It is seen in
immunocompromised patients
• Post transplant patients

Invasive aspergillosis
• CT HALO sign

CT halo sign in invasive pulmonary
aspergillosis

Hydatid disease of lung

Lung hydatid
Meniscus sign
Cumbo sign
Water lilly sign
Serpent sign
Sun rise sign / sunset sign

Water lilly sign

Canon ball opacities
• RCC
• Choriocarcinoma
• Prostatic carcinoma
• Synovial sarcoma
• Endometrial carcinoma

Silhoutte sign

Lung abscess with horizontal air fluid level

Crazy pavement pattern in pulmonary
alveolar proteinosis

• Egg Shell calcification in lymph
nodes:
• a. Silicosis
• b. Sarcoidosis
• c. Coal workers
pneumoconiosis
• d. Lymphoma following
radiotherapy
• e. Histoplasmosis
• f. Progressive massive fibrosis
• g. TB
• h. Coccidiomycosis

miliary opacities
• innumerable, small 1-4 mm pulmonary nodules
scattered throughout the lungs.
• Miliary tuberculosis,
• Pneumoconiosis (silicosis) except asbestosis
• sarcoidosis,
• Multiple metastasis from renal thyroid
breast
• Bronchopneumonia.
• Varicella
• Histoplasmosis
• Extrinsic allergic alveolitis
• Tropical eosinophilia
• Histiocytosis
• Silicosis in upper lobe
• Cardiac causes
• MS
• Pulmonary edema

Tree in bud sign

Mediastinal tumours

Anterior mediastinal masses
• 4T
• Thyroid
• Thymoma(MC)
• Teratoma  germ cell tumours
• Terrible lymphoma  lymphadenopathy
• Thoracic Aorta – Dilated or anuerysm of the ascending aorta

Middle mediastinal masses
• Aneurysm (MC)
• Bronchogenic cyst
• Carcinoma bronchus
• Distant mets / lymphnodes
• Enteric cyst

Posterior mediastinum
• Neurogenic (MC)

Thymic shadow

Thymic shadow
• Sail shaped
• Well defined lateral & inferior margins
• Does not indent tracheal shadow
• Shrink with use of steroids
• Causes widening of anterior mediastinum

Wave sign of muvley
• Wave sign of muvley  d/t indentation of
thymus on ribs

Fallen lung sign

Fallen lung sign in fractured bronchus

Emphysematous lung
• > 6 ribs
• Flattening of diaphragm
• Tubular shaped heart

Solitary pulmonary nodule
• <3cm in size
• Single discrete pulmonary opacity that is surrounded by normal lung
• Described based on 3 criteria

Causes of SPN

Margins
• Smooth & thin walled  20 % malignancy
• Scalloped margin 60 % chance of malignancy
• Spiculate margin  90 % chance
• Corona radiata  95 % chance

• Central nidus calcification
• Granuloma
• Lamellated appearance also seen in granuloma

Popcorn calcification is seen in hamartoma

Growth rate is determined by doubling time
• Time taken for a lesion to double in size
• Increase in diameter of 26 %  doubling of volume
• <30 days  benign (infn)
• 30 days – 1 yr  malignant
• > 1yr  benign

Malignant solitary pulmonary nodule Benign
• 1. Size >4cm.
• 2. Lesion crossing a fissure Rapid growth
• 3. ill defined margins
• 4. Umbilicated or notched margins
• 5. Corona radiata (spiculations)
• 6. Peripheral location
• 7. Absence of calcification
• 8. Eccentric calcification
• 9. Thick walled cavity
• a dense central nidus,
• multiple punctuate foci, and
• “bulls eye” (granuloma)
• “popcorn ball” (hamartoma) calcifications

IOC in SPN is CT scan >>PET

Causes of u/l hypertranslucent lung Causes of opacification of a hemithorax
• Rotation  MC
• Scoliosis
• Poliomyelitis
• Mastectomy
• Pneumothorax
• Emphysema
• Pulmonary embolism
• Mcleod syndrome
• Poland syndrome
• Pleural effusion
• Consolidation
• Collapse
• Massive tumour
• Fibrothorax
• Pneumonectomy
• Lung agenesis

IOC
IOC
ILD HRCT
Bronchiectasis HRCT
Calcification CT
Lung malignancy CT
Superior sulcus tumour CT >>MRI
Pulmonary embolism CT pulmonary angiography
SPN CT >>PET

Sequestrated lung segment
More common in left lower lobe

RESPIRATORY SYSTEM REVISION NOTES

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RESPIRATORY SYSTEM REVISION NOTES