Helpful radiological signs in cxr25 11-91
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Transcript of Helpful radiological signs in cxr25 11-91
Helpful Radiological Signs in CXR
A. Almasi MDIran University of Medical Sciences
Department of Radiology
Mass vs Infiltrate/ Consolidation1. First of all, you should be able to detect an abnormality
2. Then you should describe your findings
3. Putting together your different findings you can come to a diagnosis• In each of the cases below, there is an abnormal opacity in the left upper lobe (1)• In the case on the left, the opacity would best be described as well-defined. The
case on the right has an opacity that is poorly defined (2)• Therefore the left radiograph depicts a mass and the one on the right is an air
space disease (3)
Silouhette Sign
• By studying the borders of the heart, diaphragm and the aorta we can determine the anteroposterior position of a lesion on a frontal CXR.
• The border of the anatomic organ is obscured only if it is in contact with the lesion (i.e. in the same anteroposterior position).
Silhouette Sign• For the heart, the silhouette
sign can be caused by an opacity in the RML, lingula, anterior segment of the upper lobe, anterior mediastinum, and anterior portion of the pleural cavity
• This contrasts with an opacity in the posterior pleural cavity, posterior mediastinum, of lower lobes which cause an overlap and not an obliteration of the heart border
Silhouette sign in an anteriorly located mass
(bronchogenic carcinoma)
Silhuette sign in a posteriorly located lesion (lower lobe pneumonia); not obscuring the right heart border
Silhouette sign in an anterior lesion obscuring the PA but not the aortic knob
Air Bronchogram
• Visible air-filled bronchus in a background of airless parenchyma
• Most commonly seen in pneumonia and pulmonary edema
• Its presence confirms the intrapulmonary location of the lesion
Air bronchogram in pneumonia
Air Bronchogram
Causes of an air-bronchogram
Common • Expiratory film • Consolidation (air space
disease) • Cardiogenic pulmonary
edema• Hyaline membrane
disease
Rare• Lymphoma• Alveolar cell
carcinoma• Sarcoidosis• Fibrosing alveolitis• Alveolar proteinosis• ARDS• Radiation fibrosis
Air-space (acinar/alveolar) pattern or consolidation or infiltration
• Acinus is the functional unit of the lung and is defined as all the airways located distal to a terminal bronchiole.
• Acinar pattern appears when the distal airways and the alveoli are filled with fluid (transudate, exudate or blood).
• Fluid-filled acini form nodular shadows 4-8mm in diameter (acinar shadows).
• An air-filled acinus surrounded by fluid-filled acini produces air-acinogram
• These acinar shadows can coalesce into larger ill-defined homogenous or patchy opacities which are well-defined adjacent to the fissures.
• Vascular markings are usually obscured.• Air-bronchogram is characteristic
Air-space pattern characteristics
• Ill-defined nodular shadows 4-8mm in diameter
• Coalescence of these acinar nodules• Ill-defined borders of larger opacities
except where limited to a fissure• Air-bronchogram• Air-acinogram
Acinar nodules in a case of diffuse TB (bronchial spread)
Coalescing acinar nodules in pulmonary contusion (hemorrhage)
Alveolar filling pattern in a case of diffuse TB
Sharp border of an alveolar shadow confined to the minor fissure in RUL pneumonia
Typical air-space pattern in pneumonia
Common causes of an air-space pattern (Consolidation)
• Pulmonary edema: cardiogenic/noncardiogenic• Pneumonia/pneumonitis• Aspiration • Hemorrhage
Pulmonary edema
• Two basic types: –cardogenic edema: increased hydrostatic
pulmonary capillary pressure–noncardogenic edema: either altered
capillary membrane permeability or decreased plasma oncotic pressure.
Cardiogenic Pulmonary Edema• Would you favor pneumonia or CHF in this patient? Why?
What pattern is shown?
Fat Embolism (ARDS)
• Mostly peripheral distribution of the opacities contrasts with the central bat wing pattern seen in cardiogenic pulmonary edema
• Normal heart size is another suggestive evidence
Pulmonary Hemorrhage
Congestive Heart Failure• Cardiomegaly: the earliest CXR finding• Cephalization: when the pulmonary capillary wedge
pressure (PCWP) 12-18 mmHg pulmonary venous hypertension (PVH) grade I
• Interstitial edema: PCWP 18-24 mmHg, Kerley lines and peribronchial cuffing (thickening), PVH grade II
• Alveolar edema: PCWP > 24 mmHg, PVH grade III often in a classic perihilar bat wing pattern of density. Pleural effusions also often occur.
• CXR is important in evaluating patients with CHF for development of pulmonary edema and evaluating response to therapy as well.
Kerley B lines• These are horizontal lines less than 2cm long, commonly found in the lower
zone periphery. These lines are the thickened, edematous interlobular septa. • They are found in interstitial pulmonary edema, but are also seen in
lymphangitis carcinomatosa, lymphoma and other diseases too.
PVH grade I
PVH grade II
Peribronchial cuffing
PVH grade III
Solitary Pulmonary Nodule• A solitary nodule in the lung can be totally innocuous or potentially a fatal
lung cancer• Rule out presence of multiple nodules first• After detection, the initial step in analysis is to compare the film with prior
films if available. A nodule that is unchanged for two years is almost certainly benign
• If the nodule is completely calcified or has central or stippled calcium it is benign
• If the nodule is indeterminate after considering old films and calcification, subsequent steps in the work-up include ordering a CT to find subtle calcification
• Nodules with irregular calcifications or those that are off center should be considered suspicious, and need to be worked up further with a PET scan or biopsy
• The patient may choose to have an indeterminate nodule removed if there is no evidence of spread on CT as this would diagnose and treat a cancer if present
Solitary Pulmonary Nodule• This patient clearly has a solitary lung nodule present on chest x-ray.
Can you tell which lobe it's in?
Solitary Pulmonary Nodule• PA and Lateral of a subtle right lower lobe
cancer. Can you find it in the frontal projection?
Interestitial lung disease• Correlation between the CXR and severity
of the symptoms is poor• HRCT can detect interstitial changes in
earlier stages• Different patterns on CXR:
– Miliary– Ground-glass – Reticular – Reticulonodular– Honeycomb
Different patterns of interestitial involvement of the lungs
• Miliary pattern: 2-4mm well-defined nodules most often seen with TB
• Ground-glass opacity: low density opacity which does not obscure the vascular pattern of the lungs. It may be due to either an interestitial disease or mild alveolar filling
• Reticular pattern: fine irregular network of lines unlike vessels which bifurcate
• Reticulonodular pattern: presenting as reticulations plus nodules <1cm in between
• Honey combing: a network made of thin-walled cysts measuring less than one centimeter in diameter and implying end-stage lung fibrosis
The most common causes of miliary pattern
1) TB
2) Silicosis
3) Coal worker’s pneumoconiosis
4) Metastases
5) Sarcoidosis
Miliary pattern in TB
Ground glass density/opacity in usual interstitial pneumonitis
Reticulonodular pattern in idiopathic pulmonary fibrosis
Honeycomb pattern in longstanding RA with reumatoid nodules
Atelectasis/Collapse/Volume Loss
• Passive collapse: due to pleural effusion or thickening or pneumothorax
• Cicatrisation collapse: due to fibrosis (e.g. IPF, TB)
• Adhesive collapse: due to lack of surfactant• Resorption collapse: due to bronchial obstruction.
This has a lobar pattern
Anatomy of the Fissures
Radiological Signs of Atelectasis• Direct signs
– Displacement of interlobar fissures– Loss of aeration– Vascular and bronchial signs (crowding of vascular
markings, airbronchogram)
• Indirect signs– Elevation of a hemidiaphragm– Mediastinal displacement– Hilar displacement – Compensatory hyperinflation
Adhesive Atelectasis due to RDS
Passive Atelectasis due toPneumothorax
Cicatrisation Atelectasis due to TB
RUL Atelectasis
RUL Atelectasis
RUL Atelectasis
RUL Consolidation• Lobar consolidation
usually indicates bacterial pneumonia
RUL Consolidation
Thymus Sail Sign
Left Upper Lobe Atelectasis
LUL Atelectasis
LUL Consolidation
LUL Atelectasis
LUL Atelectasis
Middle Lobe Atelectasis• Right middle lobe atelectasis may cause minimal changes on the frontal chest
film. A loss of definition of the right heart border is the key finding. Right middle lobe collapse is usually more easily seen in the lateral view. The horizontal and lower portion of the major fissures start to approximate with increasing opacity leading to a wedge of opacity pointing to the hilum. Like other cases of atelectasis, this collapse may by confused with right middle lobe pneumonia.
RML Atelectasis• Right middle lobe collapse can be difficult to detect in the PA film. • The right heart border is indistinct on the PA film. • The lateral CXR shows a marked decrease in the distance between
the horizontal and oblique fissures.
Middle Lobe Consolidation
RML Consolidation vs Collapse
Left Lower Lobe Collapse
Left Lower Lobe Collapse
Left Lower Lobe Consolidation
Right Lower Lobe Collapse
Right Lower Lobe Collapse
Right Lower Lobe Consolidation
Pleural Diseases
• Pleural Effusion• Subpulmonic Effusion • Pleural Thickening • Pleural Calcification • Pneumothorax • bronchopleural fistula
Normal Pleural Space
• Visceral pleura is adherent to the lung• Space between visceral and parietal
pleura is a potential space• Infoldings of visceral pleura form
fissures.• Normally there are 2-10 cc of fluid in the
pleural space.
Appearances of Pleural Effusions
• Blunting of Costophrenic angle
• Meniscus sign• Subpulmonic
effusion• Layering
• Loculated• Laminar effusion• Opacified
hemithorax• Air-fluid levels
Blunting of Costophrenic Angle
• Normally there are 2-10cc of fluid in thepleural space
• When >75cc accumulate, the posteriorcostophrenic (CP) sulci, seen on thelateral film, become blunted
• When 200-300cc accumulate, the CPsulci on the frontal film become blunted
Blunting of the CP Angle
Normal Rt costophrenic angle
• When 200-300cc of fluid accumulate in pleural space, the usually acute costophrenic angle becomes blunted
Blunted Lt costophrenic angle
Meniscus Sign
• Pleural fluid tends to rise higher along itsedge producing a meniscus shape medially and laterally.
• Usually only lateral meniscus can be seen• The meniscus is a good indicator of the
presence of a pleural effusion.
Meniscus Sign
•Fluid rises higher along the edge of a pleural effusion producing an upside down “U” or meniscus shape.
Loculated Effusion
• Occurs secondary to adhesions which formbetween visceral and parietal pleura.
• Adhesions more common with blood(hemothorax) and pus (empyema).
• Loculated effusions have unusual shapes or positions in thorax e.g. remain at apex on erect films.
Loculated Effusion
• A loculated effusion has an unusual shape (lentiform) or position in the thoracic cavity
• This is a loculatedempyema
Laminar Effusion
• A laminar effusion collects in the loose connective tissue between the lung and the visceral pleura.
• It is not usually free-flowing.• It usually occurs with CHF or lymphangitic
spread of malignancy
Laminar Effusion
•A laminar effusion collectsbetween the lung and thevisceral pleura in the looseconnective tissue of thesubpleural space
•Laminar effusions areusually seen with CHF orlymphangitic spread oftumor
Effect of Position - Layering
Supine Erect• In the supine position, the fluid layers out posteriorly and
produces a haziness, especially near the bases. • In the erect position, the fluid falls to the bases.
Lateralized Diaphragmatic Dome in Subpulmonic Effusion
NormalSubpulmonic PE
Right Lateral Decubitus
Subpulmonic Effusion presenting as increased distance between stomach gas
and diaphragm
Subpulmonic PE Previously Normal Film
Deep Sulcus Sign
Pneumothorax
Hydropneumothorax
• If both a pneumothorax and a pleuraleffusion occur together, it is called ahydropneumothorax.
• A hydropneumothorax is usually due totrauma, surgery or bronchopleural fistula
• It is characterized by an air-fluid level inthe hemithorax.
Hydropneumothorax• A straight edge, indicative of a
fluid interface, in this case an air-fluid interface, is seen on the right.
• In order to have anair-fluid level in thepleural space, theremust be a pneumothorax present.
Y=4.2+[4.7 x (A+B+C)]
Barotrauma
Unilateral White Hemithorax