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Radiological signs in chest medicine

Aug 22, 2014

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Health & Medicine

Gamal Agmy

 
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Page 1: Radiological signs in chest medicine
Page 2: Radiological signs in chest medicine

Gamal Rabie Agmy, MD, FCCP

Professor of Chest Diseases, Assiut University

Page 3: Radiological signs in chest medicine

Air Bronchogram

• In a normal chest x-ray, the tracheobronchial tree is not

visible beyond the 4th order. As the bronchial tree

branches, the cartilaginous rings become thinner, and

eventually disappear in respiratory bronchioles. The

lumen of the bronchus contains air and the surrounding

alveoli contain air. Thus, there is no contrast to visualize

the bronchi.

• The air column in the bronchi beyond the 4th order

becomes recognizable if the surrounding alveoli is filled,

providing a contrast or if the bronchi get thickened

• The term air bronchogram is used for the former state

and signifies alveolar disease.

Page 4: Radiological signs in chest medicine

The sign implies:

•patency of proximal airways

•evacuation of alveolar air by absorption

(atelectasis), replacement (pneumonia) or

combination of both

•Consolidation, Bronchoalveolar carcinoma,

lymphoma

Page 5: Radiological signs in chest medicine
Page 6: Radiological signs in chest medicine
Page 7: Radiological signs in chest medicine

Silhouette Sign

Adjacent Lobe/Segment Silhouette

RLL/Basal segments Right diaphragm

RML/Medial segment Right heart margin

RUL/Anterior segment Ascending aorta

LUL/Posterior segment Aortic knob

Lingula/Inferior segment Left heart margin

LLL/Superior and basal segments Descending aorta

LLL/Basal segments Left diaphragm

Cardiac margins are clearly seen because there is contrast between the fluid

density of the heart and the adjacent air filled alveoli. Both being of fluid density,

you cannot visualize the partition of the right and left ventricle because there is no

contrast between them. If the adjacent lung is devoid of air, the clarity of the

silhouette will be lost. The silhouette sign is extremely useful in localizing lung lesions.

Page 8: Radiological signs in chest medicine

Atelectasis Right Lung Homogenous density right hemithorax

Mediastinal shift to right

Right hemithorax smaller

Right heart and diaphragmatic silhouette are not identifiable

Page 9: Radiological signs in chest medicine

Atelectasis Left Lung

Homogenous density left hemithorax Mediastinal shift to left

Left hemithorax smaller

Diaphragm and heart silhouette are not identifiable

Atelectasis Left Lung

•Homogenous density lef t hemithorax •Mediastinal shif t to the lef t

•Lef t hemithorax smaller •Diaphragmatic and heart silhouette are not identif iable

Page 10: Radiological signs in chest medicine

Lateral Movement of oblique and transverse fissures

Atelectasis Right Upper Lobe

Homogenous density right upper lung

field

Mediastinal shift to right

Loss of silhouette of ascending aorta

Page 11: Radiological signs in chest medicine

Atelectasis Left Upper

Lobe

Hazy density over left

upper lung field

Loss of left heart silhouette

Tracheal shift to left

Lateral A: Forward movement of

oblique fissure

B: Herniated right lung

C: Atelectatic LUL

Page 12: Radiological signs in chest medicine

Consolidation Right

Upper Lobe /

Density in right upper lung

field Lobar density

Loss of ascending aorta

silhouette

No shift of mediastinum

Transverse fissure not significantly shifted

Air bronchogram

Page 13: Radiological signs in chest medicine

S Curve of Golden

When there is a mass

adjacent to a fissure, the

fissure takes the shape

of an "S". The proximal convexity is due to a mass,

and the distal concavity is

due to atelectasis. Note the

shape of the transverse

fissure. This example represents a

RUL mass with atelectasis

Page 14: Radiological signs in chest medicine

Cut Off Sign

• When you see an abrupt ending of visualized

bronchus, it is called a "cut off sign". It indicates

an intrabronchial lesion. This is useful to identify

the etiology of atelectasis . Be careful as the

tracheobronchial tree is three dimensional and

the finding need to be confirmed with tomogram.

In the modern era, a CT scan will take care of

this.

Page 15: Radiological signs in chest medicine

Pulmonary Artery Overlay

Sign

This is the same concept as

a silhouette sign. If you can

recognize the interlobar pulmonary artery, it means

that the mass seen is either

in front of or behind it.

This is an example of a

dissecting aneurysm.

Page 16: Radiological signs in chest medicine

AV Fistula

Osler-Weber-Rendu

Syndrome

"Pulmonary nodule"

Multiple lesions Feeding vessel

Cardiomegaly

Patient presented with

severe congestive heart failure and severe iron

deficiency anemia. Had

multiple telangiectasia of

tongue, lips and

conjunctivae.

Page 17: Radiological signs in chest medicine

AV Fistula

Osler-Weber-Rendu

Syndrome

"Pulmonary nodule"

Multiple lesions Feeding vessel

Cardiomegaly

Patient presented with

severe congestive heart failure and severe iron

deficiency anemia. Had

multiple telangiectasia of

tongue, lips and

conjunctivae.

Page 18: Radiological signs in chest medicine
Page 19: Radiological signs in chest medicine

Radiographic Signs of Pneumomediastinum

Subcutaneous emphysema

Thymic sail sign

Pneumoprecardium

Ring around the artery sign

Tubular artery sign

Double bronchial wall sign

Continuous diaphragm sign

Extrapleural sign

Air in the pulmonary ligament

Page 21: Radiological signs in chest medicine
Page 22: Radiological signs in chest medicine
Page 23: Radiological signs in chest medicine
Page 24: Radiological signs in chest medicine
Page 25: Radiological signs in chest medicine
Page 26: Radiological signs in chest medicine
Page 27: Radiological signs in chest medicine
Page 28: Radiological signs in chest medicine
Page 29: Radiological signs in chest medicine
Page 30: Radiological signs in chest medicine
Page 31: Radiological signs in chest medicine
Page 32: Radiological signs in chest medicine

Potential Sources of Mediastinal Air

Intrathoracic Trachea and major bronchi

Esophagus

Lung

Pleural space

Extrathoracic Head and neck

Intraperitoneum and retroperitoneum

Page 33: Radiological signs in chest medicine

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

Page 34: Radiological signs in chest medicine
Page 35: Radiological signs in chest medicine

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

Page 36: Radiological signs in chest medicine
Page 37: Radiological signs in chest medicine

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

Page 38: Radiological signs in chest medicine
Page 39: Radiological signs in chest medicine
Page 40: Radiological signs in chest medicine

Bulging Fissure Sign

Consolidation spreading rapidly, causing lobar expansion and

bulging of the adjacent fissure inferiorly .

Historically Klebsiella pneumoniae involving the right upper lobe .

Friedlander pneumonia.

Page 41: Radiological signs in chest medicine

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

Page 42: Radiological signs in chest medicine
Page 43: Radiological signs in chest medicine

CT angiogram Sign

Identification of vessels within an

airless portion of lung on contrast-

enhanced CT .

The vessels are prominently seen

against a background of low-

attenuation material .

Associated with:

bronchoalveolar cell carcinoma

lymphoma

infectious pneumonias.

Page 44: Radiological signs in chest medicine

Fallen Lung Sign

This sign refers to the appearance

of the collapsed lung occurring

with a fractured bronchus .

The bronchial fracture results in

the lung to fall away from the

hilum, either inferiorly and laterally

in an upright patient or posteriorly,

as seen on CT in a supine patient.

DD:

Pneumothorax causes a lung to

collapse inward toward the hilum.

Page 45: Radiological signs in chest medicine

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

Page 46: Radiological signs in chest medicine
Page 47: Radiological signs in chest medicine

Thymic Sail Sign Naclerio’s V Sign

Page 48: Radiological signs in chest medicine

Flat waist Sign

This sign refers to flattening of the contours of the aortic knob and adjacent

main pulmonary artery .

It is seen in severe collapse of the left lower lobe and is caused by leftward

displacement and rotation of the heart

Page 49: Radiological signs in chest medicine
Page 50: Radiological signs in chest medicine

Finger in Glove Sign

Visible on chest radiographs or CT

•Indicates mucoid impaction within an obstructed bronchus

•Characterized by branching tubular or fingerlike opacities

Page 51: Radiological signs in chest medicine

Finger in Glove Sign

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

Page 52: Radiological signs in chest medicine
Page 53: Radiological signs in chest medicine

Hampton Hump Sign

Pulmonary infarction secondary to pulmonary embolism produces

an abnormal area of opacification on the chest radiograph, which

is always in contact with the pleural surface.

Page 54: Radiological signs in chest medicine

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

Page 55: Radiological signs in chest medicine
Page 56: Radiological signs in chest medicine
Page 57: Radiological signs in chest medicine

Halo Sign

CT shows nodular consolidation associated with a halo of ground-glass opacity

(GGO) in both apices resulting from invasive pulmonary aspergillosis.

This halo represents hemorrhage.

When seen in leukemic patients, is highly suggestive of the diagnosis of

invasive pulmonary aspergillosis.

Page 58: Radiological signs in chest medicine

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

Page 59: Radiological signs in chest medicine

Double Density Sign

•Posterior displacement of left main stem

bronchus on lateral view

•Posterior displacement of esophagus on

barium study

Page 60: Radiological signs in chest medicine

Walking Man Sign

Page 61: Radiological signs in chest medicine

Juxtaphrenic Peak Sign

This sign refers to a small triangular shadow that obscures the dome of

the diaphragm secondary to upper lobe atelectasis . The shadow is

caused by traction on the lower end of the major fissure, the inferior

accessory fissure, or the inferior pulmonary ligament.

Page 62: Radiological signs in chest medicine

Luftsischel Sign

In left upper lobe collapse, the superior segment of the left lower lobe, which is

positioned between the aortic arch and the collapsed left upper lobe, is

hyperinflated. This aerated segment of left lower lobe is hyperlucent and

shaped like a sickle, where it outlines the aortic arch on the frontal chest

radiograph.

This peri-aortic lucency has been termed the luftsichel sign, derived from the

German words luft (air) and sichel (sickle).

Page 63: Radiological signs in chest medicine

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

Page 64: Radiological signs in chest medicine

Pulmonary

hypertension Normal

Lymphadenopathy

Page 65: Radiological signs in chest medicine

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

Page 66: Radiological signs in chest medicine

Cervicothoracic Sign

• 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

Page 67: Radiological signs in chest medicine
Page 68: Radiological signs in chest medicine
Page 69: Radiological signs in chest medicine

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

Page 70: Radiological signs in chest medicine
Page 71: Radiological signs in chest medicine

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

Page 72: Radiological signs in chest medicine
Page 73: Radiological signs in chest medicine
Page 74: Radiological signs in chest medicine

Water Bottle Sign

Page 75: Radiological signs in chest medicine

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

Page 76: Radiological signs in chest medicine
Page 77: Radiological signs in chest medicine

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)

Page 78: Radiological signs in chest medicine
Page 79: Radiological signs in chest medicine

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

Page 80: Radiological signs in chest medicine
Page 81: Radiological signs in chest medicine
Page 82: Radiological signs in chest medicine

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

Page 83: Radiological signs in chest medicine
Page 84: Radiological signs in chest medicine

CT Halo Sign

Page 85: Radiological signs in chest medicine

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

Page 86: Radiological signs in chest medicine
Page 87: Radiological signs in chest medicine

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)

Page 88: Radiological signs in chest medicine

Reverse Halo Sign

•Seen in other conditions:

•Wegener’s granulomatosis

•lymphomatoid granulomatosis

•paracoccidiodomycosis

•neoplastic (metastasis)

•invasive aspergillosis

•lipoid pneumonia

Page 89: Radiological signs in chest medicine
Page 90: Radiological signs in chest medicine

Split Pleura Sign

•Seen on contrast enhanced CT of

chest

•Thickened visceral and parietal pleura

with separation by a collection

•Empyema or exudative effusion

•Exudative: bacterial pneumonia,

cancer, viral infection, PE

Page 91: Radiological signs in chest medicine
Page 92: Radiological signs in chest medicine

Tree-in-Bud Sign

•Commonly seen at thin-section CT

•Initially described in endobronchial spread

of Tuberculosis

•Recognized in diverse entities

•Small centrilobular nodules soft-tissue

attenuation connected to multiple branching

structures

Page 93: Radiological signs in chest medicine

Tree-in-Bud Sign

Page 94: Radiological signs in chest medicine
Page 95: Radiological signs in chest medicine

Crazy Paving Sign

•Scattered or diffuse GG attenuation w

superimposed intralobular and interlobular

septa thickening

•Commonly seen at thin-section CT

•Initially described in PAP

•Recognized in diverse entities

Page 96: Radiological signs in chest medicine

Crazy Paving Sign

Page 97: Radiological signs in chest medicine
Page 98: Radiological signs in chest medicine

Comet Tail Sign

•Seen on CT of the chest

•Consists of curvilinear opacity extending

from subpleural mass toward hilum

•Produced by the distortion vessels and

bronchi that lead to adjacent rounded

atelectasis

Page 99: Radiological signs in chest medicine
Page 100: Radiological signs in chest medicine

Signet Ring Sign

•Seen on CT/HRCT scans of chest

•CT finding in patient with bronchiectasis

•Ring shadow representing dilated thick-

walled bronchus associated a nodular opacity

representing pulmonary artery

•Distinguish from cystic lung lesions

Page 101: Radiological signs in chest medicine

Pearl ring sign

Page 102: Radiological signs in chest medicine