CT Applications in Chest Pathology

8/17/2019 CT Applications in Chest Pathology

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CT Applications in Chest Pathology

Objectives are as follows,

• List the types of CT

• List the indications of chest CT

• Understand the applications of chest CT

• Identify the radiological signs of common chest diseases on CT

Basics of CT

• Two dimensional representation of a three dimensional slice

• Internal structure of the organ can be reconstructed from multiple slices

•

Image display settings can be varied by adjusting WW & WL

Lung window

Mediastinal window soft tissue window!

"one window

Types of CT Scans are,


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• Conventional CT

• #igh resolution CT

Conventional CT Vs HRCT

• Conventional$ % to ' mm thic( slices are obtained contiguously) imaging''* of the lung

• HRCT$ $+,mm thin slices of lung are obtained at non$contiguous intervals)

usually to - cm apart) throughout the whole lung+ + .nly , to '* of the

lung is sampled

Indications of Chest CT

• /valuation of an abnormality identi0ed on conventional radiographs $ 1olitary

pulmonary nodule2 lung tumour2mediastinal mass

• 3iagnosing & 1taging of Lung Cancer

• 3etection of occult pulmonary metastases

• 3etection of mediastinal nodes 2masses

• 3istinction of empyema from peripheral lung abscess

• 3etection and evaluation of aortic disease

• 4ulmonary embolism

• #aemoptysis

Applications of CT

1 !etection of "#n$ T#%o#rs-+ 3iagnosis%+ 5natomic e6tent of disease $Intra and2or e6tra thoracic disease e6tent ) T7M

descriptors8+ 3ecision of therapeutic strategy $1urgery $vs$ Chemotherapy $vs$ 4alliative

Care 9esectability 2 Irresectability,+ Image guided biopsies

Lung tumours


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"enign tumours $ #armatoma) 5denoma) 5: Malformation

Malignant tumours$ 4rimary "ronchial Ca) 5lveolar cell Ca!) 1econdary

Beni$n t#%o#rs& Har%ato%a

• '( of all solitary p#l%onary nod#les are har%ato%as

• It is the %ost co%%on beni$n l#n$ t#%o#r

• They are %ostly asy%pto%atic

Har%ato%a

• 9ound) smooth mass $ increase in si;e slowly

• Calci0cation in ,* $ pathognomonic if popcorn type

•


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+ 5ssess the primary tumour

-+ 5ssess the secondary e>ect 2complications

%+ 5ssess the nodal2 other metastasis

CT appearances in pri%ary %ali$nant t#%o#r

+ 3ense irregular hilar opacity

-+ 3ense peripheral opacity

%+ 3ense irregularly cavitating lesion

8+ #ilar opacity with collapse of a segment 2whole lung

*ali$nant t#%o#r&Secondary e+ects

+ 4leural e>usion

-+ Mediastinal widening

%+ .steolytic lesions of the rib

8+ 3iaphragmatic paralysis

!etection of "#n$ Cancer lain Radio$raphy vs CT

• Contrast resolution of CT is superior to plain chest radiography

• 1igni0cantly more nodules detected on CT

The Stages of Lung Cancer

•

1tage I -o nodal %etastases and s#r$ically re%ovable


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• 1tage II )dds hilar ly%ph node involve%ent .II)/ or resectable chest

wall0%ediastinal involve%ent .IIB/

• 1tage III 5 2tensive b#t resectable disease

• 1tage III " 2tensive b#t irresectable by conventional criteria b#t still

con3ned to chest, therefore consider radical radiotherapy

• 1tage I: !istant %etastases

The Staging of Lung Cancer: International Staging System

PRIMARY TUMUR !T"

• T !ia%eter ≤ 4c%s, s#rro#nded by l#n$ 0visceral ple#ra -o involve%ent of

lobar bronchi

•

T-54c% dia%eter6 involves %ain bronch#s b#t≥

7c% distal to carina6 invadesvisceral ple#ra6 associated with atelectasis or obstr#ctive pne#%onitis e2tendin$ to

hila b#t not involvin$ entire l#n$

• T#T#%o#r of any si8e b#t with invasion of9 chest wall,diaphra$%, %ediastinal ple#ra

parietal ple#ra, parietal pericardi#%, or t#%o#r in %ain bronch#s :7c% fro% carina

b#t not involvin$ carina6 or atelectasis 0 obstr#ctive pne#%onitis of entire l#n$


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T2T

1

• T$T#%o#r of any si8e b#t with invasion of9 heart, $reat vessels, trachea,

oesopha$#s, vertebral body, carina6 t#%o#r with %ali$nant ple#ral 0 pericardial

e+#sion6 or with satellite t#%o#r nod#le.s/ in ipsilateral pri%ary&t#%o#r lobe

The CT Staging of Lung Cancer? T1 vers#s T7 lesions

The CT Staging of Lung Cancer? T1 0 T7 lesions


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The CT Staging of Lung Cancer? T4 0 T; lesions

T%

S#perior s#lc#s t#%o#rs

The CT Staging of Lung Cancer? -odal Sta$in$

• 7. -one

• 7 Ipsilateral hilar

• 7- Ipsilateral %ediastinal .incl s#bcarinal/

• 7% Contralateral %ediastinal 0 hilar or s#praclavic#lar

%etection of Lung Cancer& BIOS


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*etastases in "#n$ Cancer

"iver %%$%*

)drenals -'$%%*

Brain D$-D*

Bone ,$-*

Key point

CT remains the mainstay in the non$invasive staging of lung cancerE

Mediastinal masses

• 57T/9I.9 M/3I51TI7UM

T#FM.M5

T/95T.M5

I7T95T#.95CIC T#F9.I3 /7L59G/M/7T

LFM4#.M5 !# T's an( an L"


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.T#/9 $ LFM4#57GI.M5

57/U9F1M .< 51C/73I7G 5.9T5

*iddle %ediastini#% = *asses

• Merge with hilae and cardiac borders

• Lymphadenopathy

• "ronchogenic cyst

• 5ortic aneurysm

• Most middle mediastinal masses are due to enlarged nodes+

osterior %ediastinal %asses

•

7eurogenic tumour

• /6tramedullary haemopoeisis

• 9eticulosis) myeloma

• 4aravertebral abscess

• /nlarged paravertebral lymph nodes

• #aematoma following injury to the spine

• 5ortic aneurysm

• #iatus hernia

• 3ilated oesophagus in achalasia

Thy%o%a = CT


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Retrosternal $oiter

Commonest pleural masses

• Mesothelio)a: It is a di>use or localised pleural mass+ Large pleural e>usions are

common+ May have associated pleural pla=ues

• Pleural )etastases $ often obscured by the accompanying e>usion


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*ali$nant %esothelio%a

"#n$ )bscess

)ortic ane#rys%


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#l%onary e%bolis%

In(ications of Chest HRCT

• 3etection of lung disease in patient with pulmonary signs and symptoms or

abnormal pulm function test but normal or e=uivocal CH9

– /mphysema) /6trinisic allergic alveolitis) small airway disease)

immunocompromised patient

• /valuation of di>usely abnormal CH9

– Cystic 0brosis) 1arcoidosis) interstitial lung disease #istocytosis H) 5931


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HRCT -or%al l#n$

Basic HRCT Patterns

• Lines

• 7odules

• Consolidation

• Ground$glass .pacity

• Cysts

Linear a*nor)alities

a! thic(ened interlobular septa

b! bronchovascular interstitial thic(ening

c! reticular change

e+g


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>ibrosin$ alveolitis

"y%phan$itic t#%o#r

-od#les

• 5 nodule is a rounded density that does not correspond to a vessel+

• The anatomic distribution of nodules$$centrilo*ular) ran(o)) or interstitial$$helps

to identify potential causes

e+g$ bronchopneumonia gives nodules in a centrilobular distribution


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-od#les = Infective

?ro#nd $lass opacity

• 5 ha;y opacity that does not obscure the associated pulmonary vessels+ This

appearance results from parenchymal abnormalities that are below the spatial

resolution of #9CT+

• /+g+ alveolar wall inammation or thic(ening) with partial air$space 0lling) or with

some combination of the two+

?ro#nd $lass& In@#en8a pne#%onia


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Cysts

• 9ounded structure that is 0lled with air and usually has a thin wall+

• The cyst contents are as dar( as air surrounding the patient

• /+g+Cystic bronchiectasis

Chronic interstitial 0brosis subpleural honeycombing!

LangerhanJs cell #istiocytosis

Lymphangioleiomyomatosis

Cystic Bronchiectasis

Consolidation

CT Applications in Chest Pathology

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