chest interpretation

Get in the habit of always checking the following items before anything else. It takes a few seconds and is an important legal safe guard as well.
1.Patient's name. 2.Date exam done (very important if comparing prior exams). 3.Check for position markers - right vs. left, upright.
Other items to check before commencing with clinical review of the film include: Type of film (although this is a chest program, practice noticing if it is a plain film, CT, angio, MRI, etc.)
-Patients position - supine, upright, lateral, decubitus. -Technical quality of exam - learn what are the acceptable limits for the exam. You can't find a subtle pneumothorax if there is patient motion or the film is overexposed.
INITIAL SURVEYA basic principle to adopt is going from general observations to specific details. For instance, an absent breast shadow on a film of a patient after a mastectomy.
After completing your administrative maneuver, get a general overview of the film before zooming in on tiny detail. Notice the following because it may change the baseline normal's you use as reference points, and you may be sensitized to look for specific findings.
-General Body Size, Shape, and Symmetry -Male vs. Female -Is this an infant, child, young adult, elderly person? -Survey for foreign objects - tubes, IV lines, EKG leads, surgical drains, prosthesis, etc., as well as non-medical objects, bullets, shrapnel, glass, etc.
Three types of abnormality may be detected on the radiograph during this examination:
1. A changed appearance of a normally visualized structure; 2. A radio-opacity;
3. A transradiancy.
1. Alterations in a Normally Visualized Structure a. Transradiancy, General Observations : -The transradiancy of both lungs in corresponding zones should be equal. - In the lateral view the dorsal spine becomes increasingly transradiant inferiorly, and in adults the high retrosternal region is transradiant, though to a variable degree
b. Soft Tissue and Bone: must include the breasts and a detailed examination of the posterior, axillary, and anterior aspects of the ribs, looking particularly for evidence of surgery, fractures, notching, and changes in architecture.c. Diaphragm :
1-The costo- and cardiophrenic angles.
2-The absolute height of the diaphragm.
3- The relative height of the hemidiaphragms.
4-Clarity and margin.
5-contour.
6-curvature.
d. Root of Neck and TracheaThe upper trachea is central, but inferiorly it may deviate slightly to the right because of the aorta, and this effect becomes more marked with age. The lumen of the trachea should be more or less uniform (coronal diameter 15–25 mm,) and free of filling defects. e. The Mediastinum and Heart:The mediastinum should be central and its silhouette, in general, sharp.The mediastinal margin should be inspected for any abnormality of shape; and the visible mediastinal lines and interfaces for their integrity, position and contour.The cardiac size, contour and marginal clarity should be assessed.: f. HilaHilar shadows are made up of pulmonary arteries and veins with other components (airways, nodes). In general the hila are equally dense and approximately the same size.The left hilum is higher than the right.
g. Fissures and Vesselsthose should be checked for their position, configuration, and thickness. Normal fissures are of hairline thickness.:2. Abnormal OpacitiesOpacities must be described and analysed in detail, noting in particular their size, number, position (distribution), shape, contour, marginal clarity, and structure.Major patterns of pulmonary opacities,consoldation (air space shadowing),collapse(atelectasis),nodules(mass),cavitatory/cystic lesion,linear opacities,interstitial opacity ,pleural opacities..
a. ConsolidationConsolidation is caused by the replacement of air in distal airways and alveoli by fluid (transudate, exudate including eosinophilic exudate, blood) or, rarely, tissue.Radiologically, consolidation produces an area of increased radio-opacity of any size which may be homogeneous or non-homogeneous. Its important radiological attributes are:(i) Ill-defined Margins…(ii) Nonsegmental Distribution..(iii) Irregular Shape..(iv) Tendency for Coalescence..(v) No Volume Change..(vi) Air Bronchogram
b. Collapse (Atelectasis):..opacity with reduced volume (shifting of the trachea ,mediastinum ,fissures and hilum towrd the opacity)..elevation of the diaphragm …c. Nodular Opacities:Nodular opacities are essentially spherical. They may be single or multiple and range in size from massive (15 cm or more) to pinpoint (less than 1 mm — micronodules). Nodules more than 3 cm in diameter are called masses and multiple small nodules about 2 mm in diameter are called miliary nodules .d. Ring OpacitiesRing shadows are annular opacities with a central transradiancy and a number are due to cavitation of pre-existing nodules, masses, or consolidations. The features of ring opacities that are most useful in their evaluation are their size, number, wall thickness, wall margins, and position.
e. Linear Opacities:A linear opacity is an elongated opacity which is approximately even in width. It is useful to distinguish band shadows (5 mm or more wide) from line shadows that are thinner. Some abnormal line shadows have characteristic features that allow their identification.(i) Septal (Kerley B) lines: are short, straight, horizontal, peripheral lines that end at right angles against the pleura and .are generally 1–2 mm thick and less than 20 mm long(ii) Septal (Kerley A) lines represent deeper interlobular septa made visible by the same mechanisms that produce B lines. Septal A lines occur in any zone, start away from the lung edge, and point towards the hila. They are straight or slightly angular and are 20–30 mm long and 1–3 mm wide.(iii) The third characteristic line shadow is the parallel line shadow.
f. Interstitial OpacitiesA number of pulmonary opacities are classified as interstitial. They include: (i) nodular shadows — small rounded opacities (ii)reticular opacities in which linear and curvilinear opacities overlap, producing a net-like pattern (iii) reticulonodular opacity — a combination of (i) and (ii); (iv) ground-glass opacity, which resembles that which is seen in consolidation; (iv) septal lines; and (vi) bronchovascular/vascular changes.
Silhouette Sign Interfaces between the air in the lung and opacities of soft tissue density will have clear, sharp margins on a chest radiograph provided such interfaces are reasonably smooth and tangential to the X-ray beam. If the air in the lung at the interface is removed either by alveolar collapse (e.g. obstructive atelectasis) or substitution (e.g. consolidation), an opacity replaces the air transradiancy and the radiographic boundary will disappear because of the loss of contrast.
3. Abnormal Transradiancy: In analysing a transradiancy the following are the most useful observations:a. Presence of a Ring Shadow. b. Exclusion of Technical Causes. Once these have been eliminated, increased transradiancy must be due to reduced perfusion per unit area of lung. This may be on the basis of one or more of the following: (i) vascular obstruction (pulmonary embolism); (ii) vessel displacement (bullae); (iii) vessel destruction (generalized emphysema); (iv) compensatory hyperinflation (adjacent collapse); (v) compensatory vasoconstriction secondary to hypoventilation (airway obstruction); or, (vi) failure of development (MacLeod's/Swyer-James' syndrome) c. Exclusion of Chest Wall or Pleural Abnormality d. Assessment of Pulmonary Vessels e. Evidence of Hyperinflation f. Evidence of Air Trapping