M-4 Conf Intro Chest

8/9/2019 M-4 Conf Intro Chest

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CHEST INTRODUCTION

Technical Adequacy

In trying to determine if pathology is present in a chest radiograph

several factors have to be considered in the overall judgment of theradiograph to determine if the visual findings are pathologic or in

part are related to the radiograph itself.

Factors to be considered on all chest x-rays include:

Inspiration

Penetration

Rotation

Angulation

Orientation


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Inspiration: The volume of air in the hemithorax

will affect the configuration of the heart with

question of cardiac enlargement with a shallowlevel of inspiration. The vascular pattern in the

lung fields will be accentuated with a shallow

inspiration since the same amount of blood flow isnow distributed to a smaller volume of lung.

The level of inspiration can be estimated by

counting ribs. Visualization of nine posterior ribs,

or seven anterior ribs on an upright PA radiograph

projecting above the diaphragm would indicate a

satisfactory inspiration.


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Inspiration Expiration


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Inspiration


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Expiration

4

NOTE CHANGE IN HEART SIZE ANDVASCULARITY DUE TO EXPIRATION.


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Penetration: Refers to adequate photons traversing

the patient to expose the radiograph. This is oftenlimited in patients of large size such that there is

poor visualization of structures in the lower lung

fields and in a retro-cardiac location. The lack of

penetration renders the area whiter than with an

adequate film and can simulate pneumonia or

effusion. In an ideal radiograph the thoracic spine

should be barely perceptual viewing through thecardiac silhouette. The soft tissues at the shoulder

can also give an estimate of the relative degree of

penetration of the film.


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PenetrationCASE #1


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IS THE DIFFERENCE DUE TO CHF OR PENETRATION?


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PenetrationCASE #2


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DID YOU SEE THE NODULE ON

THE PREVIOUS FILM?


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Rotation of the patient distorts mediastinal anatomyand makes assessment of cardiac chambers and the

hilar structures especially difficult. Chest wall

tissue also contributes to increased density over thelower lobe fields simulating disease. Rotation of the

radiograph is assessed by judging the position of the

clavicle heads and the thoracic spinous process.

Ideally the clavicle heads should be equidistant fromthe spinous process.


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Rotation


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DISTORTED MEDIASTINUM DUE

TO TORTOUS AORTA AND

ROTATION.


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Orientation: In this we are making reference to the position

of the patient and the xray beam. A PA radiograph is

obtained with the x-ray traversing the patient from posterior

to anterior and striking the film. Similarly an APradiograph is positioned with the xray traversing the patient

from anterior to posterior striking the film. The cardiac

border or silhouette will appear larger on an AP radiograph

due to the magnification effect of the more anteriorly

located heart relative to the film.

Typically portable radiographs are obtained AP, as the

patient is not able to stand. Standing radiographs in thedepartment are typically obtained PA with a corresponding

lateral radiograph. The PA and lateral radiograph best

demonstrate the actual cardiac size with minimal

magnification compared to the AP exam.


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Orientation

PAAP


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PA


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AP


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Angulation: With the patient in a more

lordotic projection the clavicles will project

superiorly relative to the upper thorax again

causing some distortion of the normal

mediastinal anatomy. With the lordoticprojection of the ribs assume a more

horizontal orientation. Occasionally a lordotic

xray can be obtained intentionally to bettervisualize structures in the thoracic apex

obscured by overlying boney structures.


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Angulation


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PA


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AP LORDOTIC


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EXAMPLE OF

GOOD

INSPIRATION

PENETRATION

ROTATION

ORIENTATION

ANGULATION


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WAS THIS FILM TAKEN

IN THE UPRIGHT

POSITION?


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WHATS MISSING ?

The Rt. Shoulder!

Documents

M-4 Conf Intro Chest