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The Chest The Chest

Dr Mohamed El Safwany, MD.

Intended Learning OutcomeIntended Learning Outcome2

The student should be able to recognize technological principles of radiographic chest imaging.

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Radiation Protection: For chest radiography, a lead-rubber gonadal shield should be employed so to protect the abdomen below the chest (using vinyle-covered lead apron) around the waist for all patients of reproductive age, children, and pregnant women. Otherwise, an adjustable mobile lead shield screen must be used.

Exposure: Low contrast ( long-scale contrast) contrast must be adopted using ‘High kV Technique ’ (100 - 130 kVp) with low mAs (3 mAs) at 72 inches (180 cm) FFD (SID) on full second inspiration, to produce more shades of gray that shows fine lung markings behind the heart and lung bases due to the higher penetration. Higher mA and short exposure times (0.01 s) must be used to reduce movement blur . Overall optimum density with sufficient mAs is necessary, which can be proved by seeing faint outlines of mid and upper vertebrae and posterior ribs. A moving or high-lattice fine- line) focused grids must be used with the high kV technique. Grids should not be used with mobile and bed-side patients (mobile radiography).

For pediatrics, lower kV (60 – 70 KV) must be used with lower mAs (to reduce motion). Higher-speed films and screens are also used for pediatrics to reduce motion and exposure

dose. Correct placement of patient ID and film markers are also important.

Technical aspects

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X-ray chest must be taken in full arrested second inspiration to show the lungs well expanded and full with ‘contrasting air’. In case of pneumothorax, another full exposure on (expiration) must be done (on the same film) for diagnostic comparison purposes, with an increase of (+5 kVp) and half the usual mAs (that is 1.5 mAs, when using a high kVp technique).

Technical aspects

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All chest radiographs must be taken in ‘standing’ erect to allow the diaphragm to move down to show greater areas of the lung fields and possible chest/subphrenic abscess or air-fluid levels.

FFD for PA chest must be 72 inches (180 cm) to maintain the ‘natural’ size of the heart which is usually less in PA than in AP, and prevent geometrical unsharpness and magnification as a result of the increased OFD.

Patient’s neck must be sufficiently extended (chin up) to prevent superimposition of chin or neck on lung apices. Also, large female breasts must be displaced away from lung fields to avoid creating‘ breast shadows’.

Technical aspects

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A left lateral chest film must be done routinely as the heart is located on the left side, unless certain pathology in the right lung necessitates the need for a right lateral.

Proper CP for the chest is (T7)

Basic (routine) views are: PA and lateral. Special views include: AP or PA apical, lordatic, lateral decubitus, AP supine (or semi-erect), LAO, and LPO.

fast film screen combinations must be used with the short exposure times used.

Technical aspects

PA Chest (Normal/ ambulance patients) (Basic)PA Chest (Normal/ ambulance patients) (Basic)

Erect film shows pleural effusions, infections, atelectasis, pneumo-thorax.

Patient erect, feet apart, chin rested on film top edge, hands on lower hips, elbows partially flexed, the shoulders rotated forward (to move the clavicles below apices), top of film 5 -7 cm above the shoulders (to include the apices), exposure on 2nd arrested (inspiration), collimation and protection should be applied.

Film: HD 35x43 cm lengthwise (crosswise for large patients), and

35x35 cm for females) .CP: T7 (7 – 8 inches inferior to vertebra prominens, or 3 – 4 inch

below the jugular notch).

CR: Horizontally 90 to film center.

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PA Chest (Normal/ ambulance patients) (Basic)

For pathology involving lungs, diaphragm, and the mediastinum. kV for bedside is 70-80 with a grid, for large patients 80-100 kV with grid , film cross-wise to eliminate possible lateral cutoff.

Patient supine on trolley, trolley head raised into a semierect position, film behind the patient.

Film: HD 35x43 cm crosswise.

CP: T7 (3-4 inches below the jugular notch).

CR: 5 caudal to prevent clavicles from obscuring

the apices, FFD 120 cm, at least.

NB/ With this position it is impossible to show any

fluid levels.

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AP Chest (supine/ semierect – trolley/bedside) (special)

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AP Chest (supine/semierect – trolley/bedside) (special)

Basic (additional) projection for localizing position of a lesion, or for the heart. A grid is used.

Patient erect, turned with side of interest in close contact with the film, MSP parallel with film, arms folded over the head.

Film: HD 35x43 cm.

CP: T7.

CR: 90 horizontally through the chest.

NB/ kV 125, at 6 mAs (with grid).

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Lateral erect chest (Basic)

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Lateral erect chest (Basic)

For pathology situated posterior to the heart and great vessels (patients who can’t stand for an erect standing lateral) and for trauma.

Film: HD 35x43 cm.

CP: T7.

CR: Horizontally 90.

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Lateral chest (stretcher/wheelchair patients) (Basic)

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Lateral chest (stretcher/wheelchair patients) (Basic)

For small pleural effusions (air-fluid levels) and for pneumothorax. A (DECUBITUS) marker or (Arrow) should be used.

Patient lying on one side on radiolucent pad, chin and arms raised above head, patient back against a vertical cassette, knees flexed slightly, top of the cassetteFilm: HD 35x43 cm vertical on the couch edge.

CP: T7.

CR: Horizontally 90 to film center.

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Lateral decubitus chest (AP horizontal beam) (special)

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Lateral decubitus chest (AP horizontal beam) (special)

For pathology involving the lung fields, trachea, and mediastinal structures (including the heart).

Patient erect rotated 45 (left anterior shoulder

against film for LAO, and right anterior shoulder

against film for RAO).

Film: HD 35x43 cm.

CP: T7.

CR: 90 to film center.

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LAO, RAO chest (heart) (special)

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LAO, RAO chest (heart) (special)

For a right middle lobe collapse, or an interlobar pleural effusion. Patient standing in erect PA , then bends backward at the waist (30– 40 degrees).

Film: HD 35x43 cm.

CP: T7.

CR: Horizontally 90 to film center.

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AP lordatic chest (special)

For opacities obscured in the apical region

by the ribs or by the clavicular shadows (masses, TB, etc..).

Patient stands or sits in AP projection with the coronal plane 30 degrees to the film with the inion resting against upper border of the film.

Film: HD 35x43 cm.

CP: Sternal angle.

CR: Horizontally 90 to film center.

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AP lordatic chest (special)

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AP lordatic chest (alternative positions) (special)

Patient positioned as for PA chest.

kV is adjusted to give enough penetration of the thoracic vertebrae (just visible through the heart). The lung fields must appear over-penetrated. Exposure time 0.01 – 0.04 seconds with high mA, FFD must be 180 cm to maintain normal size of the heart.A grid is also used.

Film: HD 35x43 cm.

CP: T7 (as for the chest).

CR: 90 to film center.

NB/ Exposure during suspended inspiration (120+

kV).

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PA (penetrated) chest (heart and aorta) (Basic)

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PA (penetrated) chest (heart and aorta) (Basic)

Patient positioned as for true (left) lateral chest.

kV is adjusted to give enough penetration of the thoracic vertebrae (just visible through the heart). The Lung fields must appear over-penetrated.

Film: HD 35x43 cm.

CP: T7 (as for the chest).

CR: 90 to film center.

NB/ Exposure during suspended inspiration,

(125+ kV).

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Lateral chest (heart and aorta) (Basic)

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Lateral chest (heart and aorta) (Basic)

Obliques are done to separate the heart and the vertebral column. In the RAO, the right side must be in contact with the film, coronal plane makes 60 with the film. In LAO, the left side is in contact with the film, coronal plane makes 70 with the film.

kV is adjusted to give enough penetration of the thoracic vertebrae (just visible through the heart). Lung fields must appear over-penetrated.

Exposure: 125 kVp, 4 mAs, with grid.

CR: T7.

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LAO/RAO (heart and aorta) (special)

For cardiomegaly. The esophagus is outlined with (thick) barium and patient is positioned for a RAO.

Patient holds a mouthful of (barium sulphate) drink in the mouth, then swallow it. Exposure is made three seconds after movement of the thyroid cartilage. A LAO is also done together with PA and lateral.

Exposure: 125 kVp, 4 mAs, with grid.

CR: T7.

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RAO

RAO

Barium swallow (heart and aorta) (special)

For pathology ( e.g., soft-tissue swellings ) involving

air-filled larynx and the trachea, thyroid, thymus

glands, and the upper esophagus. A contrast

medium (barium) is used to opacify these organs.

Patient sitting or standing supine, back of the head and shoulders against film, chin raised so that RBL is

20 to the horizontal axis.

Film: HD 24x30 cm.

CP: Level of C4, with exposure during the valsalva

maneuver.

CR: Horizontally 10 cephalic to film center.

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AP larynx, pharynx, and trachea (Basic)

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AP larynx, pharynx, and trachea (Basic)

For pathology involving the air-filled larynx and the trachea, thyroid, thymus glands, and upper esophagus. A contrast medium (barium) is used to opacify these organs (usually it is a soft-tissue technique done to exclude epiglottitis in young children).

Patient sitting or in erect lateral, shoulders rotated posteriorly and depressed down, hands clasped behind the back.

CP: Midway between the thyroid cartilage and the jugular notch through C4.

Film: HD 24x30 cm.

CR: Horizontally 90 to film center.

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Lateral larynx, pharynx, and trachea (Basic)

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Lateral larynx, pharynx, and trachea (Basic)

For pathology of the sternum (fractures /other inflammatory processes).

Patient erect with arms on sides, or: Semiprone and slightly oblique (15 - 20, to the right side ) with the left arm up and the right arm down by the side.

Film: HD 24x30 cm.

CP: Center of sternum (midway between jugular

notch and the xiphoid process).

CR: Horizontally 90 to film center, exposure on

(normal) quiet breathing, or else, during a

suspended expiration.

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RAO sternum (Basic)

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RAO sternum (Basic)

For pathology of the sternum (#s, subluxation, and other inflammatory processes).

Patient erect (arms drawn to back), or in a lateral recumbent (lying on the side, arms above the head), shoulders well back.

Film: HD 24x30 cm.

CP: Center of sternum (midway between jugular notch and xiphoid process).

CR: 90 to film center, exposure during a suspended inspiration.

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Lateral sternum (Basic)

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Lateral sternum (Basic)

For joint separation and pathology.

Patient prone, pillow for head which must be turned to one side, arms up beside the head.

Film: HD 18x24 cm.

CP: At level of T2-T3.

CR: 90 to the film center, exposure done during suspended expiration.

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PA bilateral sternoclavicular joints (SCJs) (Basic)

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PA bilateral sternoclavicular joints (Basic)

For joint separation and pathology.

Patient prone, rotated 15, upside arm in front of the patient, opposite arm behind, the spinous process 1 to 2 inches lateral to midline of couch.

Film: HD 18x24 cm.

CP: At level of T2-T3.

CR: 90 to the film center, exposure during

suspended expiration.

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PAO SCJs (Basic)

Assignment

One student will be selected for assignment

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Suggested Readings

Clark’s Radiographic technology

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QuestionDescribe

radiographic principles of chest radiogram?

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Thank You

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