AP viewThe clavicles project too high into the apices.The heart magnified over the mediastinum.The ribs will appear distorted or unnaturallyhorizontalPulmonary markings decresed visibilityBlunting of costophrenic angles
Lateral ViewPositionSeen in : ant mediastinalmasses, encysted pleural fluid, postbasal consolidation
Other Views• Decubitus - useful for differentiating pleural effusions from consolidation (e.g. pneumonia) ; Loculated effusions from free fluid in the pleura.
• Expiratory view and Inspiratory viewsDemonstrates Air trapping and diaphragm movementExp : pneumothorax and interstitial shadowing
Scheme of viewing PA film1. Request form Name ,age, sex, date, clinical information2. Technical View Centering, patient position Side Markers Adequate inspiration Exposure/Penetrance3. Soft tissue and bony cage Subcutaneous emphysema, fractures4.Trachea Position, Outline5. Heart and Mediastinum Shape , Size, Displacement6.Diaphragms Outline ,Shape , Relative position7.Pleural spaces Position of horizontal fissure, costophrenic and cardiophrenic angles8.Lungs Local , generalized abnormalities, comparison of translucency and vascular marking sof the lungs
9.Hidden areas Apices, Posterior sulcus, Mediastinum, Hila, Bones10. Hila Density, Position, Shape11. Below the Diaphragm Gas shadows, Calcification
PA VIEW AP VIEW• Chin up , shoulders rotated • Taken in cases when patient forward, taken in full is too ill to stand inspiration• With plate in front of chest • Film is placed behind the and back to the X-ray back and x-ray exposure machine from front .• Scapula away from the • Scapula closer to the lung upper lung fields fields• Clavicles less apically • Clavicles less apically displaced displaced• Vertebral neural arches • Vertebral disc spaces seen seen better • Relative cardiomegaly
Technical aspects of viewing a PA film• Centering – medial ends of clavicle equidistant from spinous process at t4/5- always look for gastric bubble,aortic arch and heart to confirm normal situs.• Penetration – disc spaces+vertebral bodies visible down to t8/9• Degree of Inspiration – full inspiration ant. Ends of 6th rib or post ends of the 10th rib on right hemidiaphragm. On expiration larger cardiac shadow and basal opacity due to crowding of normal vascular markings.
Trachea• Upper part- midline• Lower part- deviates slightly around aortic knuckle- marked on expiration• Left bronchus not clearly visualized due to aorta• 25mm in males , 21 mm in females• Right paratracheal stripe- 60% N- 5mm• Angle of carina- 60 -75 degrees
Mediastinum and Heart• Mediastinum, Heart, Spine , Sternum• Cardiothoracic ratio – less than 50% in PA and less than 60% in AP. Increased in AP and expiration• Right and Left heart borders formed• Thymus- triangular Sail shaped structure – Wave sign of Mulvey
Diaphragm• Right higher than left• Normal position of diaphragm, higher in supine• Curves which steepen towards chest wall- costophrenic angles are acue• Cardiophrenic angles may be blunted due to presence of fat pads
The Fissures• Horizontal fissure seen often incompletely running from the hilum to the region of the sixth rib• Fissures seen clearly seen on lateral view• Accessory fissure- Azygos fissure comma shaped right sided triangular based peripherally
Lungs• Hidden areas- Apices, Mediastinum and hila, Diaphragms, Bones• Hila- 97% left higher than right., Clearly defined borders –concave lateral borders- mainly formed by pulmonary areteries and upper lobe veins. Lymph nodes not normal• Bronchovascular markings seen upto – 2/3rd of the lung field• Lymphatics – normally not seen
Lung zones• When describing the lungs divide them into three zones - upper, middle and lower.• Each of these zones occupies approximately one third of the height of the lungs.• The lung zones do not equate to the lung lobes.• Upper zone- from 2nd costal cartilage to axilla• Middle zone- between 2nd and 4th costal cartilage.• Lower zone- below 4th costal cartilage.
Lymph Nodes• Bronchopulmonary( hilar) nodes – appear as hilar masses• Carinal nodes- widening of the carinal angle• Tracheobronchial nodes- right paramedian stripe• Anterior, Posterior, Paratracheal, parietal
Below the diaphragm• Gas• Chilaiditis syndrome
Soft tissue and Bony Cage• Breasts may partially obscure the lungs.• Skin folds tend to be confused with consolidation as they overlap the lung fields• Sternum• Clavicle• Scapulae• Ribs- rib notching• Spine- check bone and rib destruction
ABCDEFGHI!!• Bones and Soft tissue• Airway• Cardiac Silhouette, Mediastinum.• Diaphragms• Effusion• Fields of lung• Gastric Air Bubble• Hilum• Instruments.
Kerley lines• Pulmonary lymphatics are usually not visible• Lymphatics drain the interstitial fluid and foreign particles• They run in the interlobular septa and drain to the hilum• Thickened lymphatics and surrounding connective tissue = Kerley lines• Divided into 3 types – Kerley A lines – thickened deep septa – Kerley B lines – thickened interlobular septa – Kerley C lines
Formation of Kerley B lines Acinus 5 - 6 mm in diameter alveoli, alveolar duct, resp. bronchiole 3 - 5 acini = secondary pulmonary lobule Each lobule is separated by septa (interlobular septa) Thickening of these septa = Kerley B lines
Types Kerley A line Kerley B line Kerley C lineThin Thin, transverse, faint FineNon branching Non branching Interlacing lines2 – 6 cm long 1 -3 cm long Seen throughout lung1 – 2 mm thick 1- 2 mm thick “Spider web” like appearanceRadiating from hila Lateral part of lung base extending to pleura (common in costophrenic angle)not following course of Frequently seen than A &Cartery, vein or bronchi lines Lines arranged in step ladder like pattern (0.5 to 1 cm apart) ALWAYS perpendicular to pleural surface
• Kerley B lines can be: Transient Persistent Pulmonary edema Dilated lymphatics Chronic interstitial edema Hemosiderin dust deposition Interstitial fibrosis• They are present in the base of the lung due to hydrostatic pressure and gravity
Disk atelectasis Impaired diaphragmatic motion UnderventilationCollapse of small pulmonary sub divisions Fleischner line formation
Differentiation Fleischner’s lines Kerley B lines Linear scarsFewer in number (1 -2) More in number May show fine strands emanating from bordersIrregularly placed Regularly placed (0.5 to 1 Associated pleural effusion cm gaps)Located deep in lung Superficial PermanentThicker Thin
• Nodular lesions could be classified as1. solitary pulmonary nodules2. Multiple pulmonary nodules• Solitary nodule is defined as an x-ray density completely surrounded by normal aerated lung with circumscribed margins of any shape usually 1- 6cm in greatest diameter.• If its <3cm → ‘Coin lessions’• If > 3cm → massesCannon ball lesions:Multiple nodules, widely disseminated,usually multiple, clearly demarcated 1- 2cm in diameter circular shadows throughout the lung fields (characteristic of secondary deposits)Milliary shadows : Multiple small shadows 2-4mm in diameter
Tuberculoma: It appears Round or oval, sharply circumscribed nodule that isseldom more than 4 cm in diameter. Central calcification and satellitelesions are common, as is calcification of hilar lymph nodes. This X-ray shows :Single smooth, well-defined pulmonary nodule in the left upper lobe. In the absence of a central nidus of calcification, this appearance is indistinguishable from that of a malignancy.
TUBERCULOMA:(A) Frontal and (B) lateral views of the chest show a largeleft lung soft-tissue mass (arrows) containing dense central calcification
Rheumatoid nodulesLarge nodules in pulmonary parenchyma bilaterallypresent, discrete similar to opacities of metastatic lesions –Rhuematoid arthritis
Bronchogenic CarcinomaCarcinoma of bronchus. A large, round soft-tissue mass ispresent at the right apex. Blunting of the right costophrenic angle is due toa small pleural effusion.
Pulmonary infarctionChest radiograph with ‘classical’ Chest X ray after 4 days, priorappearance of a pulmonary infarction – to treatment, showing massivea wedge-shaped lesion peripherally set increase in volume of lesion.against the pleura
Air-space (Acinar/alveolar) pattern• When distal airways and alveoli are filled with fluid, whether it is a transudate, exudate or blood, acinus forms a nodular 4-8mm shadow.• These coalesce into fluffy ill-defined round or irregular cotton-wool shadows.• Non-segmental, homogenous or patchy, but frequently well defined adjacent to fissures.
Cont…• Vascular markings usually obscured locally.• Air bronchogram and silhouette sign are characteristic• Ground-glass appearance of generalised homogenous haze with a “bat’s wing” or “butterfly” perihilar distribution may be seen, sparing the peripheral lungs.
Silhouette Sign• An intrathoracic lesion touching a border of the heart, aorta, or diaphragm will obliterate that border on the radiograph.• An intrathoracic lesion not anatomically continous with a border of one of these structures will not obliterate that border.• Eg. Lower lobe pneumonia, disease of lingula
Pulmonary Edema• Produces air space opacities with variable distribution.• Sparing of the apices and extreme lung bases.• “Butterfly” or “Bat wings” distribution – central lungs affected more.• With progression – opacities coalesce to form a “white-out” on chest radiograph.• Blurring of blood vessels occurs.• Air bronchogram – indicating intra alveolar edema.
The term collapse is used when a whole lobe or lung is involved.Atelectesis is defined as diminished volumeaffecting all or part of a lung, whichmay or maynot include loss of normal lucency in the affectedpart of lung .Pulmonary atelectasis can be divided into sixtypes, based on mechanism: resorptive, adhesive,compressive, passive, cicatrization, and gravity-dependent
LOBAR ATELECTASISRadiologic signs of lobar atelectasis :- Director Indirect .Direct signs include increased opacificationof the airless lobe and displacement offissures.
Indirect signs include displacement of hilar andcardiomediastinal structures toward the side ofcollapse, narrowing of the ipsilateral intercostalspaces, elevation of the ipsilateralhemidiaphragm, compensatory hyperinflationand hyperlucency of the remaining aeratedlung, and obscuration or desilhouetting of thestructures adjacent to the collapsed lung(eg, diaphragm and heart borders). Additionalradiologic features vary according to the site ofatelectasis.
RADIOLOGY OF PLEURAL DISEASES Nikitha James 080201018
PLEURAL EFFUSION• Pleural effusion initially manifests as basal peripheral opacities that first fill the costo- phrenic angle.
Consolidation Consolidation- replacement of air in one or more acini by fluid or solid material, but does not imply a particular pathology or etiology. Communications between the terminal airways allows fluid to spread between adjacent acini- responsible for larger area of involvement Commonest causes Acute inflammatory exudate from pneumonia. Non cardiogenic pulmonary oedema Cardiogenic pulmonary oedema Hemorrhage Aspiration
Radiologic features AIR BRONCHOGRAM- contrast between the column of air which is present in the airway and the surrounding opaque acini Normally the lung fields are radioluscent and the bronchi are not separately visualised But when, there is opacification of the alveoli due to various reasons (eg: fluid accumulation is pulmonary oedema)the bronchi stand out as radiolucent in contrast to the adjacent alveoli that are radio opaque
an x-ray for a patient with right middlezone consolidation and demonstrates air bronchograms
Silhouette sign: If the airspace adjacent to one of the normal mediastinal or diaphragmatic contours is filled with dense material i.e. consolidated, then the normal air-soft tissue interface is lost and the normally seen edge of the silhouette disappears
• On the lateral radiograph• drawing an imaginary line anterior to the trachea and posteriorly to the inferior vena cava.• The middle and posterior compartments can be separated by an imaginary line passing 1 cm posteriorly to the anterior border of the vertebral bodies.
• Approximately 60% of all mediastinal masses arise in the anterior mediastinum, 25% appear in the posterior mediastinum, and 15% occur in the middle mediastinum• Most masses (> 60%) are: – Thymomas – Neurogenic Tumors – Benign Cysts – Lymphadenopathy• In children the most common (> 80%) are: – Neurogenic tumors – Germ cell tumors – Foregut cysts• In adults the most common are: – Lymphomas – Lymphadenopathy – Thymomas – Thyroid masses
Superior mediastinum• origins of the Sternohyoid and Sternothyroid• the aortic arch• the innominate artery• the thoracic portions of the left common carotid and the left subclavian arteries• the innominate veins• the upper half of the superior vena cava• the left highest intercostal vein• the vagus, cardiac, phrenic, and left recurrent nerves; the trachea, esophagus, and thoracic duct;• the remains of the thymus, and• some lymph glands
LUNG MASS OR MEDIASTINAL MASS ?• A lung mass abutts the mediastinal surface and creates acute angles with the lung, while a mediastinal mass will sit under the surface creating obtuse angles with the lung
Anterior Mediastinum• loose areolar tissue,• some lymphatic vessels which ascend from the convex surface of the liver,• two or three anterior mediastinal lymph glands• small mediastinal branches of the internal mammary artery.
• Hilum Overlay Sign• When there is a mediastinal mass and you still can see the hilar vessels through this mass, then you know the mass does not arise from the hilum. This is known as the hilum overlay sign. Because of the geometry of the mediastinum most of these masses will be located in the anterior mediastinum.
• The four Ts make up the mnemonic for anterior mediastinal masses:• Thymoma (myasthenia, upper anterior mediatinum)• Teratoma (germ cell)• Thyroid• Terrible Lymphoma
Middle MediastinumIt contains• The heart enclosed in the • the bifurcation of the pericardium trachea and the two• the ascending aorta bronchi• the lower half of the • the phrenic nerves superior vena cava with • some bronchial lymph the azygos vein opening glands. into it• the pulmonary artery dividing into its two branches• the right and left pulmonary veins
Middle MediastinumSignsWidened paratracheal stripesAP window massDisplaced azygoesophageal recess on the rightLateral ‘doughnut’
• Adenopathy Infection (fungal and mycobacterial) Neoplasm (bronchogenic carcinoma, metastases, lymphoma, leukemia) Sarcoidosis• Aneurysm/vascular• Abnormalities of development Bronchogenic cyst Pericardial cyst Esophageal duplication cyst
On conventional radiographs look for:• Cervicothoracic Sign• Widening of the paravertebral stripes
• Cervicothoracic sign• The anterior mediastinum stops at the level of the superior clavicle. Therefore, when a mass extends above the superior clavicle, it is located either in the neck or in the posterior mediastinum. When lung tissue comes between the mass and the neck, the mass is probably in the posterior mediastinum. This is known as the Cervicothoracic Sign.