Classic Signs in Thoracic RadiologyThis poster is published under an open license. Please read the disclaimer for further details.Congress: ECR 2014Poster No.:

C-1769

Type: Educational ExhibitKeywords: Neoplasia, Inflammation, Infection, Diagnostic procedure, Education, CT, Conventional

radiography, Thorax, Mediastinum, LungAuthors: A. Manzella1, P. Borba Filho2, E. Marchiori3, G. ZANETTI4, D. Escuissato5, F. A. Felix6, E.

Albuquerque2; 1Recife, PE/BR, 2Recife, PERNAMBUCO/BR, 3Rio de Janeiro/BR, 4Niterói - Rio de Janeiro, RJ/BR, 5Curitiba/BR, 6Recife/BR

DOI: 10.1594/ecr2014/C-1769DOI-Link: http://dx.doi.org/10.1594/ecr2014/C-1769

Findings and procedure details

Fig. 2: SILHOUETTE SIGN. Chest radiograph shows middle and inferior right lobe...

Fig. 3: AIR BRONCHOGRAM SIGN. Chest CT and chest radiograph demonstrate air...

Fig. 4: SIGNET RING SIGN. Chest CT shows small bronchiectasis.

Fig. 5: POPCORN CALCIFICATION. Chest radiograph demonstrates nodule with "popcorn...

Fig. 6: TRAM-TRACK SIGN. Chest CT demonstrates tram-track sign. Schematic drawing and...

Fig. 7: TREE-IN-BUD SIGN. Chest CT shows tree-in-bud images. Schematic drawings and...

Fig. 8: CT ANGIOGRAM SIGN. Chest CT and schematic drawing.

Fig. 9: FINGER-IN-GLOVE SIGN. Chest CT, schematic drawing and illustrative picture.

Fig. 10: HALO SIGN. Chest CT shows halo sign in a patient with schistosomiasis....

Fig. 11: REVERSE HALO SIGN. Chest CT demonstrates reverse halo images in a patient with...

Fig. 12: COIN LESION. Chest CT shows a nodule in the left lower lobe. Metastasis....

Fig. 13: MILIARY SHADOWING. Chest CT. Tuberculosis.

Fig. 14: MONOD’S SIGN. Chest CT. Mycetoma. Schematic drawing.

Fig. 15: FALLEN LUNG SIGN. Chest radiograph and schematic drawing.

Fig. 16: BULGING FISSURE SIGN. Chest radiograph. Right upper lobe pneumonia. Schematic...

Fig. 17: FLAT WAIST SIGN. Chest radiograph and schematic drawing.

Fig. 18: GOLDEN S SIGN. Chest radiograph and CT images demonstrate this sign. Bronchial...

Fig. 19: BAT WING APPEARANCE. Chest radiograph, schematic drawing and corresponding...

Fig. 20: GROUND GLASS PATTERN. Chest CT images and illustrative picture.

Fig. 21: CRAZY PAVING SIGN. Chest CT with schematic drawing and illustrative picture.

Fig. 22: MOSAIC PATTERN. Chest CT with schematic drawing and illustrative picture.

Fig. 23: SANDSTORM APPEARANCE. Chest radiograph in a patient with alveolar...

Fig. 24: HONEYCOMB LUNG. Chest CT with schematic drawing and illustrative picture.

Fig. 25: WESTERMARK SIGN. Chest radiograph and schematic drawing.

Fig. 26: WAVE SIGN. Chest radiograph with schematic drawing and illustrative picture.

Fig. 27: DEEP SULCUS SIGN. Chest radiograph with schematic drawing and illustrative...

Fig. 28: TAPERED MARGINS SIGN. Chest radiographs with schematic drawings. Mesothelioma...

Fig. 29:CERVICOTHORACIC SIGN. Chest radiographs with schematic drawings. Lymphoma.

Fig. 30: 1-2-3 SIGN. Chest radiographs with schematic drawings. Sarcoidosis.

Fig. 31: HILUM OVERLAY SIGN. Chest radiograph with schematic drawing.

Fig. 32: HILUM CONVERGENCE SIGN. Chest radiograph with schematic drawing.

Fig. 33:THORACOABDOMINAL SIGN. Chest radiograph with schematic drawing. Hamartoma.

Fig. 34: WATER BOTTLE CONFIGURATION. Chest radiograph with schematic drawing and...

Fig. 35: DOUBLE DENSITY SIGN. Chest radiograph with schematic drawings.

Fig. 36: SPLIT PLEURA SIGN. Chest radiograph with schematic drawing.

SILHOUETTE SIGN

 

This classic roentgenographic sign first described by Felson in 1950 states that “an intrathoracic lesion touching a border of the heart, aorta, or diaphragm will obliterate that border on the roentgenogram

 

An intra-thoracic lesion not anatomically contiguous with a border or a normal structure will not obliterate that border

 

Reliable sign distinguishing anterior lung lesions from posterior or lower lesions

 

When two objects of the same density touch each other the edge between them disappears (figure 2)

 

Fig. 2: SILHOUETTE SIGN. Chest radiograph shows middle and inferior right lobe pneumonia.References: Radiology, Universidade Federal de Pernambuco, Hospital das Clinicas - Recife/BR

 

AIR BRONCHOGRAM SIGN

 

It occurs in infiltration or edema in tissues adjacent to patent bronchi

 

Seen on chest radiographs or CT

 

Associated with air-space disease

 

It implies: patency of proximal airways, evacuation of alveolar air by absortion (atelectasis), replacement (pneumonia) or both, consolidation, tumor, lymphoma (figure 3)

 

Fig. 3: AIR BRONCHOGRAM SIGN. Chest CT and chest radiograph demonstrate air bronchograms in patients with right upper lobe pneumonia. Schematic drawings.References: Radiology, Universidade Federal de Pernambuco, Hospital das Clinicas - Recife/BR

 

SIGNET RING SIGN

 

Seen on CT/HRCT scans of chest

 

CT finding in patients with bronchiectasis

 

Ring shadow representing dilated thick-walled bronchus associated with a nodular opacity representing pulmonary artery (figure 4)

 

Fig. 4: SIGNET RING SIGN. Chest CT shows small bronchiectasis.References: Radiology, Universidade Federal de Pernambuco, Hospital das Clinicas - Recife/BR

 

POPCORN CALCIFICATION

 

A cluster of sharply defined, irregularly lobulated, calcifications, usually in a pulmonary nodule (figure 5)

 

Popcorn calcifications within a well-circumscribed pulmonary nodule are highly suggestive of pulmonary chondroid hamartoma

 

Fig. 5: POPCORN CALCIFICATION. Chest radiograph demonstrates nodule with "popcorn calcification" in the right lower lobe representing hamartoma.References: Radiology, Universidade Federal de Pernambuco, Hospital das Clinicas - Recife/BR

 

TRAM-TRACK SIGN

 

Parallel line opacities (tram tracks) caused by thickened dilated bronchi (figure 6)

 

Seen on chest CT

 

Bronchiectasis- defined as localized irreversible dilatation of part of the bronchial tree

 

Causes:

- infection

- bronchial obstruction (endobronchial tumors, encroachment of hilar lymph nodes, foreign body aspiration)

- cystic fibrosis

- primary ciliary dyskinesia

- immunodeficiency states

- congenital anatomic defects (pulmonary sequestration, Mounier-Kuhn syndrome)  etc

 

Fig. 6: TRAM-TRACK SIGN. Chest CT demonstrates tram-track sign. Schematic drawing and corresponding picture.References: Radiology, Universidade Federal de Pernambuco, Hospital das Clinicas - Recife/BR

 

TREE-IN-BUD SIGN

 

Commonly seen at thin-section CT

 

This sign appears as small, peripheral, centrilobular soft tissue nodules connected to multiple contiguous, linear branching opacities (figure 7)

 

This radiologic term represents the mucous plugging, bronchial dilatation, and wall thickening of bronchiolitis

 

The histopathological correlate demonstrates small airway plugging with mucus, pus, or fluid, with dilated bronchioles, peribronchiolar inflammation, and wall thickening

 

Initially described in endobronchial spread of tuberculosis

 

Recognized in diverse entities

 

Causes:

- infection (bacterial, fungal, viral)

- congenital disorders (cystic fibrosis, Kartagener syndrome)

- idiopathic disorders (obliterative bronchiolitis)

- aspiration

- inhalation (toxic fumes and gases)

- immunologic disorders

- connective tissue disorders (rheumatoid arthritis, Sjogren)

- neoplasms (gastric, breast and renal cancer, Ewing sarcoma)

 

 

Fig. 7: TREE-IN-BUD SIGN. Chest CT shows tree-in-bud images. Schematic drawings and corresponding picture.References: Radiology, Universidade Federal de Pernambuco, Hospital das Clinicas - Recife/BR

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 (figure 8)

 

Low-attenuating component can be caused by production of mucin within air spaces

 

Initially described in 1990  by Im et al as a specific sign (92%) of lobar bronchoalveolar carcinoma

 

Also seen in:

- pneumonia

- pulmonary edema

- obstructive pneumonitis central tumor

- metastasis from GI carcinomas

- lymphoma

 

Fig. 8: CT ANGIOGRAM SIGN. Chest CT and schematic drawing.References: Radiology, Universidade Federal de Pernambuco, Hospital das Clinicas - Recife/BR

 

 

FINGER-IN-GLOVE SIGN

 

Visible on chest radiographs or CT

 

Indicates mucoid impaction within an obstructed bronchus

 

Characterized by branching tubular or fingerlike opacities (figure 9)

 

Originate from the hilum and are directed peripherally

 

Also seen in cases of dilated bronchi with secretions

 

Visualization of the gloved fingers is made possible by collateral air drift through the interalveolar pores of Kohn and canals of Lambert aerating lung distal to the point of mucoid impaction  (distal lung remains aerated)

 

There are two broad etiologic categories: non-obstructive and obstructive

 

Non-bstructive:

- allergic bronchopulmonary aspergillosis (ABPA)

- asthma

- cystic fibrosis (secondary to mucociliary dysfunction and thick mucous secretions)

 

Obstructive:

- neoplasms (bronchial hamartomas, lipomas, bronchogenic carcinoma,carcinoid).

- congenital (bronchial atresia, intralobar sequestration, bronchogenic cysts)

 

Fig. 9: FINGER-IN-GLOVE SIGN. Chest CT, schematic drawing and illustrative picture.References: Radiology, Universidade Federal de Pernambuco, Hospital das Clinicas - Recife/BR

 

HALO SIGN

 

Ground glass attenuation surrounding a pulmonary nodule/mass on CT images (figure 10)

 

Described by Kuhlman in 1985 in patients with invasive aspergillosis

 

In febrile neutropenic patients, the sign suggests angioinvasive fungal infection, (which is associated with a high mortality rate in the immunocompromised host) the zone of attenuation represents alveolar hemorrhage whereas the nodules represent areas of infarction and necrosis caused by thrombosis of small to medium sized vessels

 

Associated with hemorrhagic nodules and may be caused by neoplasms or inflammatory conditions

 

Familiarity with adequate clinical setting helps to narrow differentials:

- multiple nodules in immunocompromised patients could be infections, Kaposi or lymphoma

- leukemia and fever may represent invasive aspergillosis

- immunocompetent patients with a solitary nodule may indicate bronchioloalveolar carcinoma

 

 

Fig. 10: HALO SIGN. Chest CT shows halo sign in a patient with schistosomiasis. Schematic drawings.References: Radiology, Universidade Federal de Pernambuco, Hospital das Clinicas - Recife/BR

REVERSE HALO SIGN

 

Central ground-glass opacity surrounded by denser consolidation of crescentic or ring shape, at least 2 mm thick (figure 11)

 

First described by Voloudaki in 1996

 

Kim in 2003 used the term reverse halo

 

Found to be relatively specific for cryptogenic organizing pneumonia (COP)

 

Seen in other conditions:

- Wegener’s and lymphomatoid granulomatosis

- paracoccidiodomycosis

- neoplastic (metastasis)

- invasive aspergillosis

- lipoid pneumonia

- schistosomiasis

 

 

Fig. 11: REVERSE HALO SIGN. Chest CT demonstrates reverse halo images in a patient with schistosomiasis. Schematic drawings.References: Radiology, Universidade Federal de Pernambuco, Hospital das Clinicas - Recife/BR

COIN LESION

 

The term coin lesion was defined by Thornton et al in 1944 as a solitary lesion, 1 to 5 cm in size, round or oval with well defined margins

 

Solitary, round, circumscribed shadows found in the lungs in x-ray or CT examinations (figure 12)

 

Smaller than 3 centimeters in diameter

 

Common causes:

- tuberculosis

- coccidioidomycosis

- histoplasmosis

- neoplasms (primary bronchogenic carcinoma, metastatic tumors, bronchial adenomas etc)

- cysts

- vascular anomalies

 

 

Fig. 12: COIN LESION. Chest CT shows a nodule in the left lower lobe. Metastasis. Schematic drawing and illustrative picture.References: Radiology, Universidade Federal de Pernambuco, Hospital das Clinicas - Recife/BR

MILIARY SHADOWING

 

The term miliary derives from the radiograqphic picture of diffuse, discrete nodular shadows about the size of a millet seed

 

Innumerable, small (1-4mm) pulmonary nodules are seen scattered throughout the lungs (figure 13)

 

It can be seen in:

- tuberculosis

- histoplasmosis

- sarcoidosis

- rheumatoid arthritis

- pneumoconiosis

- COPD 

- pulmonary siderosis

- bronchoalveolar carcinoma

- metastasis (thyroid, kidney, trophoblast and some sarcomas)

 

 

Fig. 13: MILIARY SHADOWING. Chest CT. Tuberculosis.References: Radiology, Universidade Federal de Pernambuco, Hospital das Clinicas - Recife/BR

 

MONOD’S SIGN

 

Air surrounding fungus ball or mycetoma (figure 14) in preexisting air cavity (old tuberculosis, histoplasmosis, sarcoidosis, neoplasm)

 

It should not be confused with the air crescent sign which is seen in recovering angioinvasive aspergillosis and heralds improvement in the condition

 

The air around the mycetoma is often crescent shaped and hence, the term air crescent sign is often used interchangeably by many to refer to both pathological processes

 

Fig. 14: MONOD’S SIGN. Chest CT. Mycetoma. Schematic drawing.References: Radiology, Universidade Federal de Pernambuco, Hospital das Clinicas - Recife/BR

 

FALLEN LUNG SIGN

 

This sign refers to the appearance of the collapsed lung occurring with a fractured bronchus (figure 15)

 

It refers to the collapsed lung in a dependent position, hanging on the hilum only by its vascular attachments and was first described by Oh et al in 1969 and by Kumpe et al in 1970

 

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

Fig. 15: FALLEN LUNG SIGN. Chest radiograph and schematic drawing.References: Radiology, Universidade Federal de Pernambuco, Hospital das Clinicas - Recife/BR

BULGING FISSURE SIGN

 

The bulging fissure sign refers to lobar consolidation causing lobar expansion and bulging of the adjacent fissure inferiorly (figure 16)

 

Historically Klebsiella pneumoniae involving the RUP- Friedlander pneumonia

 

Although previously reported in up to 30% of patients with Klebsiella pneumonia, the finding is identified less commonly today, most likely due to rapid prophylactic implementation of antibiotics.

 

The most common infective causative agents are:

- Klebsiella pneumoniae

- Streptococcus pneumoniae

- Pseudomonas aeruginosa

- Staphylococcus aureus

 

It may also be seen with bronchoalveolar carcinoma and tuberculosis

 

Fig. 16: BULGING FISSURE SIGN. Chest radiograph. Right upper lobe pneumonia. Schematic drawing.References: Radiology, Universidade Federal de Pernambuco, Hospital das Clinicas - Recife/BR

 

FLAT WAIST SIGN

 

Indicates left lower lobe collapse

 

Visualized on frontal views

 

Hilar structures shift downward and rotation of heart produces flattening of cardiac waist (figure 17)

 

Fig. 17: FLAT WAIST SIGN. Chest radiograph and schematic drawing.References: Radiology, Universidade Federal de Pernambuco, Hospital das Clinicas - Recife/BR

 

GOLDEN S SIGN

 

Described by Ross Golden in 1925

 

Resembles a reverse S shape

 

It can be seen on PA/lateral views and CT

 

This sign is typically seen with right upper lobe collapse

 

The medial portion of minor fissure is convex inferiorly due to a central mass and the lateral portion of the fissure is concave inferiorly (figure 18)

 

It can be observed in cases of bronchial carcinoma, primary mediastinal tumor, metastasis and enlarged lymph nodes

 

Fig. 18: GOLDEN S SIGN. Chest radiograph and CT images demonstrate this sign. Bronchial carcinoma.References: Radiology, Universidade Federal de Pernambuco, Hospital das Clinicas - Recife/BR

 

BAT WING APPEARANCE

 

Bat's wing or butterfly pulmonary opacities refer to a pattern of bilateral perihilar shadowing (figure 19)

 

It is classically described on a frontal chest radiograph but can also refer to appearances on chest CT

 

Causes:

- pulmonary edema (especially cardiogenic)

- pneumonia (aspiration pneumonia, PCP, viral, lipoid)

- inhalation injury (noxious gas, liquid)

- pulmonary alveolar proteinosis

- pulmonary hemorrhage (e.g. Goodpasture syndrome)

- lymphoma

- leukaemia

- bronchoalveolar carcinoma

 

 

Fig. 19: BAT WING APPEARANCE. Chest radiograph, schematic drawing and corresponding picture.References: Radiology, Universidade Federal de Pernambuco, Hospital das Clinicas - Recife/BR

GROUND GLASS PATTERN

 

Ground glass opacity is a hazy, increased attenuation of lung with preservation of bronchial and vascular margins (figure 20)

 

It is a nonspecific radiologic finding

 

It is caused by partial filling of air spaces, interstitial thickening, partial collapse of alveoli, normal expiration, or increased capillary blood volume

 

It can be seen with alveolar wall inflammation or thickening, with partial air-space filling, or with some combination of the two

 

Common causes:

- pulmonary edema

- adult respiratory distress syndrome (ARDS)

- viral, mycoplasmal, and pneumocystis pneumonias

hypersensitivity pneumonia

- pulmonary hemorrhage

- other diffuse interstitial lung diseases 

 

Fig. 20: GROUND GLASS PATTERN. Chest CT images and illustrative picture.References: Radiology, Universidade Federal de Pernambuco, Hospital das Clinicas - Recife/BR

 

CRAZY PAVING SIGN

 

Scattered or diffuse ground glass attenuation with superimposed intralobular and interlobular septa thickening (figure 21)

 

Commonly seen at thin-section CT

 

Initially described in pulmonary alveolar proteinosis

 

Recognized in diverse entities

 

Causes:

- infection (Pneumocystis jiroveci pneumonia, organizing pneumonia, usual interstitial pneumonia, non-specific interstitial pneumonia, and exogenous lipoid pneumonia)

- neoplasm (bronchioloalveolar carcinoma)

- pulmonary alveolar proteinosis

- sarcoidosis

- respiratory bronchiolitis with interstitial lung disease

sanguineous (pulmonary hemorrhage syndromes, ARDS)

 

Fig. 21: CRAZY PAVING SIGN. Chest CT with schematic drawing and illustrative picture.References: Radiology, Universidade Federal de Pernambuco, Hospital das Clinicas - Recife/BR

MOSAIC PATTERN

 

Patchy ground glass opacicities, resulting in a mosaic pattern of lung attenuation (figure 22)

 

Such a pattern can be seen in infiltrative lung disease, airway abnormalities (e.g., asthma, bronchiolitis obliterans), and chronic pulmonary vascular disease (e.g., chronic thromboembolic disease)

 

The distinction between these three entities can be made by observing the size of the pulmonary vessels in the area of increased lung attenuation (increased in both airway disease and vascular disease, but not in infiltrative disease), and by examining air trapping on expiratory scans (indicating airway disease)

 

Fig. 22: MOSAIC PATTERN. Chest CT with schematic drawing and illustrative picture.References: Radiology, Universidade Federal de Pernambuco, Hospital das Clinicas - Recife/BR

 

SANDSTORM APPEARANCE

 

Seen on CT or chest X-ray

 

The appearance is given by the presence of diffuse, scattered, bilateral areas of micronodular calcifications (sandstorm appearance)

 

Pulmonary alveolar microlithiasis (PAM) should be considered (figure 23) 

 

PAM is an uncommon chronic disease characterized by calcifications within the alveoli which occurs in the absence of any known disorder of calcium metabolism

 

On CT scans diffuse ground-glass opacities throughout both lungs can be seen in association with calcified nodules

 

Fig. 23: SANDSTORM APPEARANCE. Chest radiograph in a patient with alveolar microlithiasis and illustrative picture.References: Radiology, Universidade Federal de Pernambuco, Hospital das Clinicas - Recife/BR

 

HONEYCOMB LUNG

 

The term “honeycomb lung” first appeared in the English literature in 1949 (Oswald andParkinson)

 

Radiologically, in the latest version from the Fleischner Society, it is defined as “clustered cystic air spaces, typically of comparable diameters on the order of 3–10 mm but occasionally as large as 2.5 cm... usually subpleural and characterized by well-defined walls” (figure 24)

 

Recent understanding indicates that “honeycombing is often considered specific for pulmonary fibrosis and is an important criterion in the diagnosis of usual interstitial pneumonia (UIP)”

 

Causes:

- idiopathic interstitial pneumonia

- diffuse alveolar damage

- asbestosis

- interstitial granulomatous diseases

- eosinophilic granuloma

 

Fig. 24: HONEYCOMB LUNG. Chest CT with schematic drawing and illustrative picture.References: Radiology, Universidade Federal de Pernambuco, Hospital das Clinicas - Recife/BR

 

WESTERMARK SIGN

 

Described by Neil Westermark in 1938

 

Chest radiograph and CT show increased lucency or hypoattenuation (figure 25)

 

Typically signifies either occlusion of a larger lobar/segmental artery or widespread small vessel occlusion

 

Represents oligemia distal to PE; seen only in 2% of patients

 

Sign results from combination of dilatation pulmonary arteries proximal embolus and collapse of distal vasculature

 

Low sensitivity 11%, high specificity 92%

 

Fig. 25: WESTERMARK SIGN. Chest radiograph and schematic drawing.References: Radiology, Universidade Federal de Pernambuco, Hospital das Clinicas - Recife/BR

 

WAVE SIGN

 

Sign produced by lateral indentation of thymus by adjacent anterior ribs resembling a wave (figure 26)

 

This sign in seen in the pediatric population and represents a normal thymus

 

Fig. 26: WAVE SIGN. Chest radiograph with schematic drawing and illustrative picture.References: Radiology, Universidade Federal de Pernambuco, Hospital das Clinicas - Recife/BR

 

DEEP SULCUS SIGN

 

The presence of radiolucency in a deep costophrenic sulcus on a supine thoracic radiograph is characteristic of a pneumothorax in a supine patient (figure 27)

Seen on X-rays in supine position

 

Intrapleural air rises to the highest portion of the hemithorax leading to the presence of a lucency in the anteromedial, subpulmonic, and lateral basilar space adjacent to the diaphragm

 

30% pneumothoraces are undetected

 

It is useful in confirming suspected pneumothorax on AP supine radiography in compromised patients, such as those in the intensive care setting  

 

Fig. 27: DEEP SULCUS SIGN. Chest radiograph with schematic drawing and illustrative picture.References:  internet

 

TAPERED MARGINS SIGN

 

Lesions in the chest wall, pleura or mediastinum have smooth tapered borders and obtuse angles  (figure 28)

 

While parenchymal lesions usually form acute angles

 

Fig. 28: TAPERED MARGINS SIGN. Chest radiographs with schematic drawings. Mesothelioma and thymic lymphosarcoma.References: Radiology, Universidade Federal de Pernambuco, Hospital das Clinicas - Recife/BR

 

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 be outlined by air (figure 29)

 

Uppermost border of the anterior mediastinum ends at level of clavicles, so when the cephalic border of a mass is obscured at or below the level of the clavicles, it is deemed to be a “cervicothoracic lesion” involving the anterior mediastinum

 

Middle and posterior mediastinum extends above the clavicles (figure 29)

 

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

 

Fig. 29: CERVICOTHORACIC SIGN. Chest radiographs with schematic drawings. Lymphoma.References: Radiology, Universidade Federal de Pernambuco, Hospital das Clinicas - Recife/BR

 

1-2-3 SIGN

 

Characterized by bilateral hilar and right paratracheal lymphadenopathy  so-calledGarland triad or 1-2-3 sign (figure 30)

 

Suggestive of sarcoidosis

 

Separation between nodes and heart which is not seen in lymphoma

 

Fig. 30: 1-2-3 SIGN. Chest radiographs with schematic drawings. Sarcoidosis.References: Radiology, Universidade Federal de Pernambuco, Hospital das Clinicas - Recife/BR

 

HILUM OVERLAY SIGN

 

Described by Benjamin Felson

 

If hilar vessels are sharply delineated it can be assumed that the overlying mass is anterior or posterior (figure 31)

 

If mass is inseparable from pulmonary arteries, structures are adjacent to one another

 

Fig. 31: HILUM OVERLAY SIGN. Chest radiograph with schematic drawing.References: Radiology, Universidade Federal de Pernambuco, Hospital das Clinicas - Recife/BR

 

HILUM CONVERGENCE SIGN

 

Used to distinguish between a prominent hilum and an enlarged pulmonary artery

 

If branches of PA converge toward central mass, is an enlarged PA (figure 32)

 

If branches of PA converge toward heart rather than mass, is a mediastinal tumor

 

Fig. 32: HILUM CONVERGENCE SIGN. Chest radiograph with schematic drawing.References: Radiology, Universidade Federal de Pernambuco, Hospital das Clinicas - Recife/BR

 

THORACOABDOMINAL SIGN

 

Posterior costophrenic sulcus extends more caudally than anterior basilar lung

 

Lesion extending below the dome of diaphragm must be in posterior chest whereas lesion terminating at dome must be anterior (figure 33)

 

Thoracoabdominal signs were described by Felson

Fig. 33: THORACOABDOMINAL SIGN. Chest radiograph with schematic drawing. Hamartoma.References: Radiology, Universidade Federal de Pernambuco, Hospital das Clinicas - Recife/BR

 

 

WATER BOTTLE CONFIGURATION

 

Seen in pericardial effusion

Causes:

- inflammatory

- infectious

- malignant

- autoimmune processes within the pericardium

 

Chest radiography shows an enlarged cardiac silhouette (figure 34) 

 

Fig. 34: WATER BOTTLE CONFIGURATION. Chest radiograph with schematic drawing and illustrative picture.References: Radiology, Universidade Federal de Pernambuco, Hospital das Clinicas - Recife/BR

 

DOUBLE DENSITY SIGN

 

On frontal chest radiographs, this sign presents as a curvilinear density projecting over the right retrocardiac region, indicating left atrial enlargement

 

The curvilinear line represents the inferolateral margin of the left atrium (figure 35)

 

The double density sign may be observed in patients without cardiac disease; however, there is a semiquantitative measurement to estimate the left atrial diameter and better estimate whether it is a real finding

 

Fig. 35: DOUBLE DENSITY SIGN. Chest radiograph with schematic drawings.References: Radiology, Universidade Federal de Pernambuco, Hospital das Clinicas - Recife/BR

 

SPLIT PLEURA SIGN

 

Seen on contrast enhanced CT of chest

 

Separation and enhancement of the visceral and parietal pleural layers on CT  is considered strong evidence of empyema

 

Normally, individual pleural layers are not discernable as discrete structures

 

Empyemic fluid fills the pleural space, resulting in thickening and enhancement of the pleura with a denotable separation (figure 36)

 

It can also be seen with exudative effusion

 

Causes:

- bacterial pneumonia

- cancer

- viral infection

- PE

Fig. 36: SPLIT PLEURA SIGN. Chest radiograph with schematic drawing.References: Radiology, Universidade Federal de Pernambuco, Hospital das Clinicas - Recife/BR