CXR signs pdf - كتابة الطلاب

Signs in Thoracic Imaging

Carlos H. Previgliano MD

Associate Professor Radiology

Director of Cardiothoracic Radiology

Louisiana State University

– Shreveport

Objectives

• Recognize some important radiologic

signs in thoracic imaging

• Understand the mechanism of these

thoracic radiologic signs

• Establish diagnosis of particular thoracic

diseases using these signs

Radiologic Signs

• Radiologic signs are recognizable and

characteristic patterns

• Used to describe abnormalities

• Visualized on imaging methods

• Aid in the diagnosis and subsequent

treatment of different diseases

Air Bronchogram Sign

• Occurs in infiltration or edema in tissues

adjacent to patent bronchi

• Visualized on chest radiographs or CT
• Associated with airspace disease
• Absence in obstructive atelectasis
• Darker tubular densities are seen

• The sign implies:

• patency of proximal airways
• evacuation of alveolar air by

absorption (atelectasis), replacement
(pneumonia) or combination of both

• Consolidation, tumor, lymphoma

Air Bronchogram Sign

Air Crescent Sign

• Can be visualized in X-rays and CT
• Crescentic collection of air within

consolidation or nodular opacity

• Seen in pulmonary cavitary process
• Usually announces recovery
• It is a result of increased granulocyte

activity

• Characteristic of invasive pulmonary

aspergillosis

• Tumor, hematoma, Wegener

granulomatosis, hydatid cyst, TB,
nocardiosis, bacterial abscess

• Not confused with Monod’s sign

• air surrounding fungus ball or mycetoma in

preexisting cavity

Air Crescent Sign

Continuous Diaphragm Sign

• Described by Levin in 1973
• Normally central part of diaphragm is

lost due to apposition of heart

• Air interposed between the heart and

diaphragm results in gas-tissue interface

• Seen on chest radiographs
• Characteristic of pneumomediastinum

Deep Sulcus Sign

• Seen on radiographs in supine position
• Characteristic of pneumothorax
• 30% pneumothoraces are undetected
• Lucency in lateral costophrenic angle
• Air collects anteriorly and basally
• Useful in neonates and ill patients
• Include lateral costophrenic angles

Ring Around Artery Sign

• Visualized on lateral chest radiographs
• Lucency along or surrounding RPA
• Characteristic of pneumomediastinum
• Usually is accompanied by other

ancillary signs:

• continuous diaphragm sign
• Naclerio’s V sign
• thymic sail sign

Thymic Sail Sign

Naclerio’s V Sign

Flat Waist Sign

• Described by Kattan and Wlot in 1976
• Indicates left lower lobe collapse
• Visualized on frontal views
• Perfectly symmetrical PA or AP view
• Hilar structures shift downward and

rotation of heart produces flattening of
cardiac waist

Finger-in-Glove Sign

• Visible on chest radiographs or CT
• Indicates mucoid impaction within an

obstructed bronchus

• Characterized by branching tubular or

fingerlike opacities

• Originate from the hilum and are

directed peripherally

• Also seen in cases of dilated bronchi

with secretions

• Distal lung remains aerated by collateral

drift through interalveolar pores (pores
of Kohn) and Lambert canal

Finger-in-Glove Sign

Golden S Sign

• Can be seen on PA/Lateral views & CT
• Described by Ross Golden in 1925
• Typically seen with RUL collapse, can

also be seen w collapse of other lobes

• Resembles a reverse S shape also

referred as reverse S sign of Golden

• Medial portion of minor fissure is convex

inferiorly due to a central mass

• Lateral portion of the fissure is concave

inferiorly

Golden S Sign

• Should raise suspicion of central

neoplasm:

• bronchial carcinoma
• primary mediastinal tumor
• metastasis
• enlarged lymph nodes

Golden S Sign

Luftsichel Sign

• German for sickle of air (luft: air sichel:

crescent)

• Paramediastinal lucency due to

interposition of lower lobe apex between
mediastinum and shrunken upper lobe

• Occurs more commonly on the left than

in the right

Double Density Sign

• Indicates left atrial enlargement
• Occurs when right side of the left atrium

pushes into adjacent lung

• Splaying of the carina
• Superior displacement of left main stem

bronchus on frontal view

• Posterior displacement of left main stem

bronchus on lateral view

• Posterior displacement of esophagus on

barium study

Double Density Sign

Walking Man Sign

Doughnut Sign

• Detect mediastinal adenomegaly
• Lateral chest radiograph
• Subcarinal lymphadenopathy
• Mass posterior to bronchus intermedius

and inferior hilar window

• CT primary modality for detecting

mediastinal lymphadenopathy

Normal

Lymphadenopathy

Pulmonary hypertension

Silhouette Sign

• If an intra-thoracic radio-opacity is in

anatomic contact with a border of heart
or aorta will obscure that border

• An intra-thoracic lesion not anatomically

contiguous with a border or a normal
structure will not obliterate that border

• Definition given by B. Felson in 1950

Silhouette Sign

• Reliable sign distinguishing anterior lung

lesions from posterior or lower lesions

• When two objects same density touch

each other the edge between them
disappears

Silhouette Sign

Silhouette/structure

• Upper R heart/asc. Ao
• Right heart border
• Upper left heart border
• Left heart border
• Aortic knob
• Hemidiaphragm

Contact with lung

• Ant segment RUL
• RML (medial)
• Ant segment LUL
• Lingula (anterior)
• Apical portion LUL
• Lower lobes

Cervicothoracic Sign

• Used to determine location of

mediastinal lesion in the upper chest

• Based on principle that an intrathoracic

lesion in direct contact with soft tissues
of the neck will not outlined by air

• Uppermost border of the anterior

mediastinum ends at level of clavicles

• Middle and posterior mediastinum

extends above the clavicles

• Mediastinal mass projected superior the

level of clavicles must be located either
within middle or posterior mediastinum

• More cephalad the mass extends the

most posterior the location

Cervicothoracic Sign

T1+C

Thoracoabdominal Sign

• Posterior costophrenic sulcus extends

more caudally than anterior basilar lung

• Lesion extends below the dome of

diaphragm must be in posterior chest
whereas lesion terminates at dome must
be anterior

• Cervicothoracic and thoracoabdominal

signs were described by Felson

Tapered Margins Sign

• A lesion in the chest wall, pleura or

mediastinum have smooth tapered
borders and obtuse angles

• While parenchymal lesions usually form

acute angles

1-2-3 Sign

• Characterized by bilateral hilar and right

paratracheal lymphadenopathy

• so-called Garland triad or 1-2-3 sign

• Suggestive of sarcoidosis
• Separation between nodes and heart

which is not seen in lymphoma

Epicardial Fat Pad Sign

• Indicates pericardial effusion
• Kremens and Torrance in 1955 were the

first to draw attention in this sign

• Epicardial fat allows the silhouette of two

layers pericardium to appear separate
from the heart

• Normally pericardium measures 1-2 mm

• Thickness exceeding 2 mm suggests

pericardial effusion

• Widening of pericardial shadow creates

appearance of inward displacement of
epicardial fat

• Rarely is due to extrapericardial disease

Epicardial Fat Pad Sign

Pericardial Effusion

Imaging Findings

• Conventional radiography

• water bottle configuration
• loss of retrosternal clear space
• epicardial fat pad sign

• Echocardiogram study of choice
• CT may detect small effusions (50 cc)
• MRI characterize fluid

Water Bottle Sign

Hampton’s Hump Sign

• Described by Audrey Hampton in 1940
• Peripheral wedge-shaped opacity due to

infarction

• Pleura-based consolidation in the form

of truncated cone w base against pleural
surface and apex pointing toward hilum

Westermark Sign

• Described by Neils Westermark in 1938
• Chest radiograph and CT show

increased lucency or hypoattenuation

• Typically signifies either occlusion of a

larger lobar/segmental artery or
widespread small vessel occlusion

Westermark Sign

• Represents oligemia distal to PE
• Seen only in 2% of patients
• Sign results from combination of

• dilatation pulmonary arteries proximal embolus
• collapse of distal vasculature

• Low sensitivity 11%, high specificity 92%

Fleischner Sign

• Described by Felix Fleischner
• Enlargement proximal pulmonary

arteries on plain film or angiography

• PA enlargement due to embolus
• Commonly in the setting of massive PE
• It has relatively low sensitivity
• Abrupt tapering of an occluded vessel

distally (knuckle sign)

Hilum Overlay Sign

• Described by B. Felson
• If hilar vessels are sharply delineated it

can be assumed that the overlying mass
is anterior or posterior

• If mass inseparable pulmonary arteries

structures are adjacent to one another

Hilum Convergence Sign

• Described by B. Felson
• Used to distinguish between a prominent

hilum and an enlarged pulmonary artery

• If branches of PA converge toward

central mass is an enlarged PA

• If branches of PA converge toward heart

rather than mass is a mediastinal tumor

Fallen Lung Sign

• Partial or complete tear of tracheal/mainstem

or lobar bronchi is a result of penetrating or
blunt trauma (high speed road accident)

• 1.5% of cases of blunt chest trauma
• 80% tracheo-bronchial ruptures within 2.5 cm

of carina

• Fallen lung sign is highly specific but

uncommon finding

Fallen Lung Sign

• Two mechanisms in blunt trauma:

- reflex closure glottis causes rise pressure

- shearing forces produced deceleration and

rotation

• Airway injury may be obscured by other

injuries

• Many cases remain undiagnosed until

complications develop

CT Angiogram Sign

• Finding may be seen on CT of chest

after IV contrast material administration

• Consists of enhancing branching

pulmonary vessels in homogeneous low-
attenuating consolidation

• Low-attenuating component can be

caused by production of mucin within air
spaces

• Initially described by Im in 1990 as a

specific sign (92%) of lobar BAC

• Also seen in:

• pneumonia
• pulmonary edema
• obstructive pneumonitis central tumor
• metastasis from GI carcinomas
• lymphoma

CT Angiogram Sign

CT Halo Sign

• Ground glass attenuation surrounding a

pulmonary nodule/mass on CT images

• Described by Kuhlman in 1985 in

patients with invasive aspergillosis

• Associated w hemorrhagic nodules and

may be caused neo or inflammatory

• Disease pathologically active with tumor

spread, hemorrhage or inflammation

CT halo sign: Diseases

Lee YR et al. British Journal of Radiology 2005;78:862-865

Halo Sign

• Should be familiar with adequate clinical

setting help to narrow differentials

• multiple nodules immunocompromised

patients could be infections, Kaposi or
lymphoma

• leukemia or BMT and fever may represent

invasive aspergillosis

• immunocompetent patients with a solitary

nodule may indicate BAC

Reverse Halo Sign

• Central ground-glass opacity surrounded

by denser consolidation of crescentic or
ring shape, at least 2 mm thick

• First described by Voloudaki in 1996
• Kim in 2003 used the term reverse halo
• Found to be relatively specific for crypto-

genic organizing pneumonia (COP)

Reverse Halo Sign

• Seen in other conditions:

• Wegener’s granulomatosis
• lymphomatoid granulomatosis
• paracoccidiodomycosis
• neoplastic (metastasis)
• invasive aspergillosis
• lipoid pneumonia