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Basic about knowing the chest x-ray & Interpretation.
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x-ray Tube NORMAL CHEST X-RAY Table Dr. Bijay Kumar Yadav (1st Year Radiology Resident) I.K KSMA, Bishkek Film cassette
Wilhelm Conrad Roentgen - Father of Radiology • Nov 8, 1895 – Discovered unknown radiations with photographic effect which he named ‘axa rays’ • He got the Nobel prize in 1901.
Common views of the chest X-Ray: • PA (Postero-anterior) view • AP (Antero-posterior) view • Lateral view • Lateral Decubitus • Oblique view • Apical / Lordotic view • Paired Inspiratory - Expiratory view
1. PA VIEW: • Most commonly ordered radiological investigation. • Posterior-Anterior (PA) is the standard projection • PA views are of higher quality and more accurately assess heart size than AP images • PA projection may not always be possible
2. AP VIEW: • Lower quality • Heart magnification (farther from film) • Clavicles are projected more cranially above lung apex • Scapulae overlie lung fields • Ribs appear horizontal • Gastric bubble is absent
PA view v/s AP View IN PA VIEW:- • Clavicles don’t project too high into the apices or thrown above the apices (more horizontal) • Heart wont be magnified over the mediastinum therefore preventing the appearance of cardiomegaly • Scapula are away from the lung fields • Ribs are obliquely oriented in PA view • Spine and posterior ends of ribs are clearly seen
3. LATERAL VIEW • Routinely left lateral film obtained • In specific lesion, the side of the interest is positioned adjacent to the film • Should be viewed along with the PA film
CHEST X-RAY: Systemic Approach • Technical Aspects • Trachea • Mediastinum & Heart • Hila • Diaphragm • CP Angles • Lungs: • Fields (Zones) • Fissures • Pulmonary Vessels • Bronchial Vessels • Hidden Areas • Bony Framework • Soft Tissues
A. Technical Aspects: • Patient Name, Date • Adequate inspiration • Centering & Rotation • Exposure\Adequate penetration • Motion • Side markers
a. Inspiration • The diaphragm should be found at about the level of 9 - 10thposterior rib or 5 - 6thanterior rib on good inspiration Inspiration Expiration Note Changes In Heart Size And Vascularity Due To Expiration.
Inspiration - Expiration • Films taken after maximal inspiration & expiration • Advantage • Helps in detection of focal or diffuse air trapping – advantage in suspecting FB & small pneumothorax • Demonstration of diaphragmatic movement
b. Penetration • On a good PA film, the thoracic spine disc spaces should be barely visible through the heart but bony details of the spine are not usually seen. • On the other hand penetration is sufficient that bronchovascular structures can usually be seen through the heart.
UNDERPENETRATION: Likelihood of missing an abnormality overlying by another structure OVERPENETRATION: Results in loss of visibility of low density lesion e.g. Early Consolidation
c. Centering & Rotation • Can be assessed by observing the clavicular heads and determining whether they are equal distance from the spinous process of the thoracic vertebral bodies. • Good centering: 1/3 of heart is to right & 2/3 to left of midline.
c. Motion: • Cardiac margin, diaphragm and pulmonary vessels should be sharply marginated in a completely still patient.
B. TRACHEA: • Should be examined for: • Narrowing • Displacement • Intraluminal lesions • Position: Central, slightly deviated towards Right around the aortic knuckle • Calibre: • Even • Max. Coronal: 25mm (M), 21mm (F)
C. MEDIASTINUM & HEART: • Central dense shadow is formed by: • Heart • Mediastinum • Sternum • Spine
Cardiac Shadow • Good centering: • Heart: • 2/3 left • 1/3 right • In chest x-ray heart examined for size, shape, position, silhouette.
Size measurement: • CT ratio: < 50% • Transverse cardiac diameter: < 15.5 cm (M) < 14.5 cm (F) • Heart size appears enlarged on expiration, supine film, AP film & when diaphragms are elevated
Silhouette sign: • The silhouette sign is the absence of depiction of an anatomic soft-tissue border resulting from the juxtaposition of structures of similar radiographic attenuation. • Density difference delineation of the outline. • There are four basic densities in x-ray images: • Gas • Fat • Water / soft tissue • Bone / calcium • Loss of density difference of the adjacent structures loss of silhouette.
D. HILA: • Formed by superior pulmonary vein & Basal pulmonary artery (Radiological Hilum) • 97% - left hilum is higher (left pulmonary artery is above bronchus) • Hila should be of equal density, similar size & clearly defined concave lateral borders
Structures in the Hilum • Pulmonary arteries & upper lobe veins-significant contribution to hilar shadow • Normal LN- Not seen in plain radiography • Bronchi- walls seen end on
E. DIAPHRAGM: • Right higher – Not more than 3 cm. • May lie in same level & In small % left higher (~3%)
On inspiration – Anterior 6th rib , Posterior 10th rib (Erect film) • Both domes – gentle curves- steepen towards posterior angles • Clearly defined upper borders except area where heart rests & anterior cardio-phrenic angles (fat pad) • Loss of outline – adjacent tissue no air-consolidation or pleural effusion • Free intra peritoneal gas-under surface of diaphragm: 2-3mm thick
Diaphragm (Normal Variants) • Diaphragmatic Hump: Rt side anteriorly • Eventration: Part of the muscle is absent- Left side • Scalopping: Rt side- short curves convex upwards • Muscle Slips: Rt side- short curves concave upwards
Left v/s Right Dome Of Diaphragm: • Anterior left hemidiaphragm is obliterated by the cardiac contact; right is seen in entirity • By identifying the fissures: left oblique fissure is contacts diaphragm ~5 cm behind the anterior costophrenic angle • On left lateral film, the right anterior and posterior costophrenic sulci should project beyond the corresponding left sided sulci as a result of x-ray beam divergence • By seeing air in stomach and splenic flexure below the left hemidiaphragm
CP Angles • Acute and well defined • Obliterated when diaphragms are flat
E. LUNGS: • Trachea • Carina • Right and Left Pulmonary Bronchi • Secondary Bronchi • Tertiary Bronchi • Bronchioles • Alveolar Duct • Alveoli
ZonesOf Lungs • Lower border of 2nd & 4th ribs separates the zones zone 1 zone 2 zone 3
Lobes Of Lungs • Right:- Upper, Middle & Lower • Left:- Upper (Includes Lingular segment) & lower
RUL • The Right upper lobe (RUL) occupies the upper 1/3 of the right lung. • Posteriorly- The RUL is adjacent to the first three to five ribs. • Anteriorly- The RUL extends inferiorly as far as the 4th right anterior rib
RML • The right middle lobe is typically the smallest of the three, and appears triangular in shape, being narrowest near the hilum
RLL • The right lower lobe is the largest of all three lobes, separated from the others by the major fissure. • Posteriorly, the RLL extend as far superiorly as the 6th thoracic vertebral body, and extends inferiorly to the diaphragm. • Review of the lateral plain film surprisingly shows the superior extent of the RLL.
Right Lobe Fissures • These lobes can be separated from one another by two fissures. • The minor fissure separates the RUL from the RML, and thus represents the visceral pleural surfaces of both of these lobes. • The major fissure oriented obliquely extends posteriorly and superiorly approximately to the level of the 4thvertebral body.
LUL • The lobar architecture of the left lung is slightly different than the right. • Because there is no defined left minor fissure, there are only two lobes on the left; the left upper
LLL • Left lower lobes • These two lobes are separated by a major fissure, identical to that seen on the right side, although often slightly more inferior in location. • The portion of the left lung that corresponds anatomically to the right middle lobe is incorporated into the left upper lobe.
Fissures Of Lungs • Major: Right & Left oblique Fissure • Minor: Right Horizontal Fissure
Pulmonary Vessels • Measure the right descending Pulmonary artery Diameter- (16mm in Male &15mm in Female) • Distribution of flow from apex to base • At first intercostal space– normal vessels not more than 3 mm in diameter • Erect- Lower lobe vessels prominent • Supine- Equalize • Distribution of flow from central to peripheral -tapering • Vascular lung markings- Central 2/3rd
F. HIDDEN AREAS: • Apices:Partially obscured by ribs, costal cartilage, clavicles & soft tissues • Central lesions obscured by mediastinum and hila • Posterior & lateral basal segments of lower lobes & posterior sulcus obscured by the downward curve of the posterior diaphragm • Hidden areas due to bones
G. BONY STRUCTURES: • RIBS • SCAPULA • CLAVICLES • SPINE • STERNUM