cxr handbook

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chest x-ray survivalwww.scrubbingup.comcopyright 2006

s noor

bmbs

First edition 2006

The right of the author to be identified as the Author of this Work has been asserted in accordance

to the Copyright, Designs and Patents Act 1988.

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or

transmitted in any form or by any means, electronic, mechanical, photocopying, recording or other-

wise without prior permission from the publisher.

Disclaimer: Although the authors do their utmost to ensure the reliability of all information con-tained within, no responsibility is held for the material's accuracy or for any actions taken based on

this information. Readers are encouraged to confirm that all information is correct, up to date, and

in keeping with current medical practice.


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contents

Preface

Introduction

Identify the structures

A systematic approach

The normal chest x-ray

Clinical cases:

Dextrocardia

Pneumothorax

Pneumonia

Pneumoperitoneum

Pleural effusions

Tumours

Lobar collapse

PneumonectomyPulmonary oedema

Cardiomegaly

Cardiac failure

Interstitial fibrosis

Cavitations

Fractures

Mastectomy

Presenting your findings & passing

the exam

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preface

This chest x-ray guide was written with only one purpose: to get you competent enough

and confident enough to interpret a chest x-ray and discuss your findings with examiners.

By doing so, we hope this guide helps you to pass any up coming examinations you may

have. This guide does not include lateral chest x-ray films, often not required for medical

students teaching.

We assume (probably correctly) you are all beginners; a few of the easy going students

may not have even seen a chest x-ray before. We know most of you have missed clinical

teaching sessions in radiology because it was just too boring or you slept through it be-

cause the dark radiologists room was too warm and comfortable.

We assume you are panicking because finals are soon around the corner.

We know time is a major factor and that all you want is the important need to know

facts. No time wasting! We want to help you to pass, even if it means scraping through by

the skin of your teeth (like most of us did in the past).

Also note, this chest x-ray guide was not written to make you overnight radiologists, ex-

perts in your field or even make the list of top ten geeks in your medical school. It is not

designed to teach you abstract theory or every delicate intricacy about the exciting world

of chest x-rays. This, we will happily leave to those big boring textbooks, those long tedi-

ous lectures but more importantly, we can leave all that fun until after you have success-fully passed finals.

S. NOOR


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introduction: 1

The chest x-ray is one of the most common and valuable investigations requested by doc-

tors. Most patients who are admitted to the hospital seem to have one, whether they really

needed it or not is another question altogether! You will inevitably review at least one

chest x-ray every day in your early career as a doctor - how very depressing, get used to it.

Before you begin to interpret the x-ray, you first must know what a chest x-ray is. It is ba-

sic information but there is always one radiologist who takes a disproportionate amount of

pleasure in asking simple questions that makes every one look stupid. So here is a very

brief summary (skip this if time is limited).

X-rays are a form of electromagnetic radiation. They have a wavelength in the

range of 10 to 0.01 nanometres.

On an x-ray:

White = Bone / Calcified tissue

Black = Air

Anything in between = everything else!

A chest x-ray is a radiological image of the thorax taken using x-rays. The effectiveradiation dose from this procedure is about 0.1 mSv (millisievert). This is about the

same as the average person receives from background radiation in 10 days. A chest

x-ray is considered a low dose of radiation.

The chap most associated with x-rays is Wilhelm Conrad Rontgen (German physi-

cist, born 1845, died 1923). He won the first nobel prize for physics, 1901. Radiolo-

gists love this guy! Go Conrad!


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introduction: 2

What are the different views? (A summary of the important ones)

1. Posteroanterior (PA)

This is the standard view for chest radiographs. This means the front of the patients chest

is against the film, the x-rays come through from the back and out the front. Just imagine

being shot with a bullet from the back (posterior) and out through your front (anterior).

2. Anteroposterior (AP)

This is used for unwell patients. Sick patients are difficult to get out of bed so the x-rays

need to be shot from the front of the chest and come out the back. The anterior structures

of the chest (e.g. heart) are magnified on this view and therefore difficult to assess accurate

heart size.

3. Lateral

This is shot from side to side. It helps localize any abnormality identified on the PA view.

It is not used all that commonly in the exam setting so we are ignoring it.

4. Supine

The supine position is a position of the body is lying down with the face up. This is more

practical for infants and ill patients. Again the heart size cannot be accurately assessed.

5. Erect

Erect and semi-erect is with the patient standing / sitting up. It makes air under the dia-

phragm or fluid within the lungs more prominent.

6. Expiratory

With the patient breathing out, a pneumothorax becomes more apparent.


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identify the structures: 1

To fully appreciate a chest x-ray, you must and identify the anatomy. The following la-

beled x-rays should help (some ribs on the left have been outlinedobviously!):

The bones:

Remember: There are 12 Thoracic vertebra and then towards the bottom of the film you

may see 1 or 2 lumbar vertebra.

Note: It is often difficult to count the ribs. Remember you can see the front and the back of

each rib, so trace them round with care. If necessary outline them with your finger but it

does look rather unprofessional. Try to visualize them in 3D if possible!

Clavicle

Head of humerus

Scapula

Thoracic vertebra

Lumbar vertebra

1st Rib

3rd Rib

5th Rib

7th Rib


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The mediastinum, heart and diaphragm:

It is important to recognize the midline structures:

Note: The heart should take up no more than half of the width of the thoracic cavity. One

third of the heart should be on the right of midline, two thirds on the left. The contours of

the right ventricle (it is the most anterior chamber of the heart).

Around the hila are branching pulmonary vessels, the main bronchus and lymph nodes.

Trachea

Right hilum

Right atrium

Right

hemidiaphragm

Costophrenic

angle

Arch of aorta

Left hilum

Left atrium

Left ventricle

Stomach gas

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The lungs:

Note: There are three lobes on the right, two on the left. The lobes are divided by the hori-

zontal fissure (between right upper and right middle lobe) and the oblique fissures

(between right lower and right middle, between left upper and left lower lobes). These fis-sures are difficult to identify on an AP film unless there is fluid within the fissures. It is

therefore often difficult to assess the lobes individually and it is best to describe your find-

ings in zones (upper, middle and lower zones) .

The white arrows highlight the vascular markings which fan out across the lungs (these are

the smaller pulmonary vessels).

Lung apex

Right upper

lobe

Right middle

lobe

Right lower

lobe

Left upper

lobe

Left lower

lobe


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a systematic approach: 1

For beginners and for students taking exams, a systematic approach is essential for suc-

cessful interpretation of an x-ray. In reality (not in the secluded life of medical students),

no self respecting doctor requires such a system, nor do we have the endless time to review

one x-ray in such detail. You guys, however, need to learn a system before reaching the

same immense level as us!

Every radiologist will teach their own perfect system on how to interpret a chest radio-

graph. They insist you learn it and if you do not use their system, they snigger at you and

dismiss you as worthless. However, contrary to the radiologists belief, no method is per-

fect. All have their merits and flaws. The key to success is to develop a system you are

confident and familiar with, something you can rely on when you are faced in an exam

situation, sweating like a dog.

We will describe one such method to review a chest x-ray, step by step. These steps will be

described in detail. Feel free to adapt the technique to your own personal preference when

you are confident enough.

1. Identify the patients age, sex and the x-ray type

2. Is the chest x-ray satisfactory?

3. Any foreign bodies/objects?

4. The trachea, mediastinum and heart

5. The diaphragm

6. The lung fields

7. Soft tissues

8. The bones


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1. Identify the patients age, sex and the x-ray type

The best way to start interpreting a chest film is to try to gain as much information about

the patient as possible from the markings on the film itself. This will allow you time to set

the clinical scene and gather your thoughts.

Firstly, identify if the film is PA or AP, erect, supine, portable etc. Usually there will be

markings on the film suggesting what view it is. If there are no markings, presume it is a

PA. If you identify an AP film for example, you can presume you are looking at an ill pa-

tient who was to sick for a PA. This will aid you in your eventual interpretation.

The patients age may give you a huge clue about the diagnosis. For example, a young per-

son is unlikely to have lung cancer. Usually the date of birth is printed on the film, so look

for it and work out the age or at least if they are young, middle aged, or elderly.

It is useful although not essential to figure out if its a film of a male or a female. The easi-

est way to do this is to look for the breast of course (if there is no name present on the

film)!

So before you even start the difficult task of interpretation, you already have some vitalclues. You could have a twenty year old male with a standard PA film, or an 87 year old

female taken as a portable AP film. Your mind should already be racing of possible diag-

noses! Voila, you are on your way to reading your first x-ray! Well done!


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2. Is the chest x-ray satisfactory?

You will hear lots of doctors mumble to themselves: Its such a poor chest x-ray, how can

I possibly interpret it. Often is it just an excuse for not being able to make a confident di-

agnosis, but there are such things as poor films. It is important for you to identify the good

from the bad. Look for the following criteria:

Is the chest x-ray complete?

You cant fully interpret an x-ray is half of it is missing! The x-ray must include all the

relevant body parts for it to be complete. You need to be able to see the clavicles, all the

ribs, the diaphragm, the costophrenic angles, the apices of the lungs etc. If half the lung is

missing, or the diaphragm is absent, you may miss the important diagnosis. So if the film

is incomplete, it is important to comment on this.

Is there adequate penetration?

Good penetration is a key aspect of the chest x-ray. Under penetrated or over penetrated

films make it difficult to interpret. A good way of assessing penetration is being able to

see the lower thoracic vertebral bodies through the heart.

Is the film rotated?

A rotated film gives you a distorted view of the anatomy and can lead you to make misin-

terpretations of normal structures or missing abnormal structures. The easiest way of iden-

tifying rotation is to view the spinous processes of the thoracic vertebrae midway between

the medial ends of the clavicles.


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An example of an incomplete x-ray:

This is a rather unremarkable looking radiograph. Only trouble is the costophrenic angles aremissing. How do you know there is not a pleural effusion at the bases for example?


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An example of an under penetrated x-ray:

This is obviously a rubbish x-ray. It is under penetrated because there is too much ofthe white stuff, and you cant see the thoracic vertebra behind the mediastinum or

heart.


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An example of an over penetrated x-ray:

Here there is probably some over penetration meaning too much x-rays are gettingthough the body. The lung fields perhaps looking a little hollow an the thoracic verte-

bra too prominent behind the mediastinum. Any low density lesion could easily be

missed as the x-rays may have over penetrated right though it.

Also note the hand on the left! This film is of a child who obviously needed encourage-

ment!


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An example of a rotated film:

Wow what is going on here? Well clearly this radiograph is not straight! The medialends of the clavicles should be well aligned with the thoracic vertebra behind it. This

chap is clearly rotated! Note how the mediastinal contours distorted and you can view

the descending aorta coming form the arch of aorta. Poor film really!

Descending

aorta


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3. Any foreign bodies/objects?

Foreign bodies within or on the patient are usually the first thing noticed when viewing an

x-ray. You need to be able to recognize the obvious otherwise you will look like an idiot in

front of the examiner. It is a good idea to identify them early as it may give you a clue to

the clinical scenario. Examples include ECG leads, oxygen masks, endotracheal tubes, NG

tubes, central lines, swallowed objects, pacemakers, jewelry, nipple piercing etc!

Here are some examples:

Wow! What is that? Dont worry, its only a pacemaker! If the pacemaker has two wires

going into the heart it is a dual chamber pacemaker. This one is a single.


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Commonly a chest x-ray is performed to ensure a feeding NG (nasogastric) tube is in

the right place:

The NG tube is radio-opaque so that it can be visualized with an x-ray to confirm its

position. Here you can see it clearly passing below the level of the diaphragm and intothe stomach.


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Now take a look at this NG tube:

Oh dear, where is this NG tube going? The right main bronchus! Yikes, let us hope

they did not commence feeding!


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Here are a few more common objects to look out for and important to recognize:

Two items of note here. Firstly, there is a line entering the internal right jugular vein,

presumably for central IV access. Secondly is an ECG lead on the right chest wall withthe obvious lead attached.


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When faced with an object you are unclear about, try to use all the limited knowledge

you have to solve it. Firstly, work out where it is, where it starts, where it ends and

identify any structures it involves.

Ok so this is a short tube like structure, descending from the neck area downwards. It is

in the same area of the trachea! So folks, what is it? A tracheostomy! Very good, sim-

ple isnt it?


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More examples of foreign objects

Yes objects can be inside or outside the patient. Some structures are obviously recognizable;some are not and cause you grief unless you can think on your feet.


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Another interesting example:

Mmm, very fashionable. Bilateral pierced nipples! Painful!


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What the hell is this? Is this patient impaled on a fence or something? Help! Come on, use

your imagination

Well, I have only ever seen one x-ray like this. This is a corset! Try to think lateral boys andgirls, it may get you out of a spot of bother.


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4. The trachea, mediastinum and heart

Ok enough of the foreign bodies, lets get down to business.Start at the trachea. It

should be central. Any deviation from the center may indicate pathology.

From the trachea, work your way downwards on both sides along the mediastinal con-

tours. Ensure the mediastinum is also central and it should not be too wide (wide = ap-

proximately over 8cm), this may indicate pathology including aortic aneurysm or medi-

astinal lymphadenopathy.

Continuing downwards, the first structure you should come to is the aortic arch on the

left.This is often calcified in the elderly and usually an incidental finding.

The next structures are the pulmonary vessels and lymph nodes around the hila. Look

for any enlarged nodes or lesions here; you may pick up a tumour.

Then take a look at the heart. Two thirds should lie on the left side of the chest, one

third on the right. The left border is made up of the left atrium and ventricle, the right

made up of the right atrium. The right ventricle is anterior and therefore its contours

are not visualized.

Assess the size of the heart; it should be no more then half of the width of the thorax.

Note, the heart and mediastinal width cannot be accurately assessed using AP films.

5. The Diaphragm

Now trace from the heart along the diaphragm. Look at the cardiophrenic and costo-

phrenic angles. Ensure they are crisp and clean. Blunting here may indicate an effusion.

Look for air under the right side of the diaphragm (air under the left is usually the

stomach!). The right diaphragm is often higher than the left, the liver pushing it up-

wards.


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6. The lung fields

Now examine the lung fields. The lungs should be black (containing air of course) but not

totally black! There should be vascular markings extending throughout to the peripheries.

Start by outlining the contour of the lung fields, ensuring you can see these marking. If the

contours are black (lucent), it may indicate a pneumothorax. In particular concentrate on

the apices of the lung, a common place to miss a pneumothorax.

Work your way inwards and look for any obvious abnormal white areas - shadowing or

lesions.

7. Soft tissues

Take a peek at any of the soft tissues. Look for the breast shadows; make sure one breast is

not missing. Glance up at the neck; are there any swellings that shouldnt be there? Is there

any air within the tissue? Could there be surgical emphysema?

8. The bonesExamine the bones thoroughly. It is very easy to miss obvious abnormalities because you

are concentrating on the lungs. Outline the bones, ensure there are no fractures. Remember

the clavicles and humerus as well as the ribs. Assess the bone quality; are there any trans-

parencies within the bone structure? Could these be bony lesions?


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the normal chest x-ray: 1

Chest x-rays, like people, are slightly different. No two chest x-rays are the same. You have

to be confident identifying what is normal before it becomes easy to identify the abnormal.

Radiologists always show us films of small abnormalities and are surprised we can not spot

it. Students are inexperienced and unfamiliar with subtle variations of the chest x-ray. It is all

about repetitive training for your eyes and mind!

So feast your eyes on the following normal radiographs and if you are very keen, go through

them all with the systematic approach you have just learnt! Geeks!

This is a normal chest radiograph. Notice however the size of the breasts! This is obviously a

female or a male with severe gynaecomastia (man boobs)!


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This is an AP portable film. It was probably taken because the patient was acutely unwell.

However there is nothing abnormal on this radiograph to suggest a cause for being unwell.

Remember, the heart appears to be larger but this an illusion as it is an AP film. Overall, we

can conclude this film as having normal appearances


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Again, a rather unremarkable radiograph! Remember that the air under the left hemidia-

phragm is usually the stomach!


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clinical cases: dextrocardia

Ok, this is arguably a normal chest x-ray. However, in an exam situation, it is not. Stay sharp

and on your toes! Always look for the markings on the film saying which side is which. On

this film, the heart is clearly on the right side of the patient. This can either mean the radio-

graph has been put up in the light box incorrectly or there is a dextrocardia. It is present in

present in 0.01% of the population and is a potential examination banana skin! Watch out!

How to present: This is a satisfactory PA chest film of a man. With the correct annotation

noted, the heart border appears on the right hand side. There are no other major abnormali-

ties detected. This patient has dextrocardia.


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clinical cases: pneumothorax

As you are all aware (Im sure), a pneumothorax is air within the pleural space resulting in

collapse of the lung on the affected side. However, please beware! Failure to diagnose a

pneumothorax in an exam is a potential automatic fail. It is a possible life threatening condi-

tion and medical students are expected to recognize it. So all of you slackers, concentrate

now. First look at the following film and then we will discuss it.

How to present: This is an AP portable film. There is air within the right pleural cavity and

a clear outline of a collapsed right lung. The mediastinal structures are possibly deviated to

the left but there is some rotation. I can see no obvious rib fractures or evidence of any iatro-

genic procedures. The findings are consistent with a pneumothorax.


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A pneumothorax can either be a simple or a tension pneumothorax. Not going into too much

detail but any doctor ordering an x-ray of a tension pneumothorax will likely see the patient

dead before the radiographer arrive! A tension pneumothorax is an immediate life threaten-

ing condition - it requires a clinical diagnosis and urgent treatment. So technically, you

should never see an x-ray of a tension pneumothorax but I am sure it is has happened.

A simple pneumothorax is pretty straight forward to diagnose on a radiograph. When assess-

ing the lung fields, look for any obvious well defined radiolucent (black) areas surrounding

the edge of one side. If in doubt, look towards the peripheries and see if the vascular mark-

ings extend towards the edges. If vascular markings are present, you can rule out a pneu-mothorax. However if they seem to be significantly missing, there may well be a pneu-

mothorax with a collapsed lung.

Associated with a tension pneumothorax include mediastinal shift away from the affected

side (as the increasing air is pushing the midline structures away). That is all you need to

know to successfully diagnose a pneumothorax. If you want to look really smart, look for

any possible causes. Pneumothoracies are often spontaneous with no cause but also look for

traumatic or iatrogenic causes.

The radiologist may ask how you would treat this. Simply respond with:

In the case of tension pneumothorax, I would insert a large bore cannula into the second

intercostal space, mid-clavicular line on the affected side. Following this, I would insert a

chest drain into the fifth intercostal space in the mid-axillary line! Thats good enough for

the pass, you are the man!

Tips:

Look for a black outline on the periphery of the lung field. Ensure you examine the api-

ces of the lung carefully as a small pneumothorax can be missed.

Assess for mediastinal shift, this may indicate a tension pneumothorax

Look for causes

Remember the life saving treatment.

If in doubt if a true pneumothorax is present, suggest to the examiner an expiratory film

may help clarify.


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This is the same patient as the case above. Wow look, the pneumothorax has resolved. The

lung is inflated, look at the vascular markings now. Also note at the bottom, a cheeky chest

drain within the pleural cavity! Yes my friends, your expert management has saved him, I

have taught you well! There is lots of other problems with this chest x-ray but at least the

pneumothorax is treated!


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clinical cases: pneumonia

Pneumonia is an infection or inflammation of the lung parenchyma (lung tissue). It is a very

common exam case so you must get used to recognizing it. Pneumonia, although easily iden-

tifiable on a plain film, is quite frustrating for the budding medical student. This is because

pneumonia comes in all shapes and sizes and is quite frustrating to describe accurately. Any-

how let us try to go through it systematically. Peek at the following film:

How to present: This is a supine chest film with some slight rotation. There is a large con-

fluent opacity in the lower and mid zones of the right lung. The mediastinal structures appear

to be in the midline. The right hemidiaphragm is raised. Overall this film represents consoli-

dation in the right lung, consistent with a lobar pneumonia


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There are many causes of pneumonia with different infecting organisms and different pres-

entations. Unfortunately a chest x-ray can not often distinguish between them.

The only value of the chest x-ray is to identify and localize the pneumonia and perhaps as-

sess the severity. However even the severity of a pneumonia on a chest x-ray may not even

correspond fully with the clinical picture as the radiological changes remain for some time

even after the episode has resolved. Likewise a patient may have severe pneumonia and

there maybe no x-ray changes at all! How annoying!

The x-ray changes

The lung tissue is involved so obviously we are looking within the lung fields to

diagnose a pneumonia

With inflammation, infection and exudates, classically the areas involved appear

more densely white.

Consolidation on a chest x-ray often implies opacification due to the above.

Consolidation can be described as patchy, diffuse, or confluent.

When consolidation on the x-ray begins to distort the borders of the normal struc-

tures (heart and diaphragm) we get a silhouette sign.

Air within areas of consolidation are often due to air remaining in the affected

bronchi. This appears as lucent areas within the density and is called an air bron-

chogram

There are two patterns of pneumonia to look out forlobar and bronchopneu-

monia.


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Lobar pneumonia:

The inflammatory changes are confined to a single lobe.

Each loch lobar pneumonia has a different x-ray appearances

.More than one segment involved is called multilobular pneumonia obviously!

Bronchopneumonia:

This causes a more diffuse widespread pneumonia

There are irregular areas of bilateral opacification

Observe the following set of radiographs and learn!

There is patchy consolidation in the left lower zone and the right mid zone


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How to present: This is a rotated AP erect portable film. There is extensive confluent

opacities in both the right and left mid and lower zones. This is consistent with a widespread

pneumonia

Alsonotice the patients teeth! Dont they look funny! Some are missing!


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Spot the pneumonia!


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clinical cases: pneumoperitoneum

Pneumonia is an infection or inflammation of the lung parenchyma (lung tissue). It is a very

common exam case so you must get used to recognizing it. Pneumonia, although easily iden-

tifiable on a plain film, is quite frustrating for the budding medical student. This is because

pneumonia comes in all shapes and sizes and is quite frustrating to describe accurately. Any-

how let us try to go through it systematically. Peek at the following film:

How to present: This is a satisfactory AP erect film of a male. The most obvious abnor-

mality is air under the diaphragm. There are no other abnormalities. This case would be con-

sistent with a perforated viscus.


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clinical cases: pneumoperitoneum

A pneumoperitoneum literally means air within the peritoneum (abdominal cavity). Al-

though the symptoms of the patient are predominantly within the abdomen, the chest x-ray is

often crucial to the diagnosis. A perforated viscus (hollow organ) is a surgical emergency,

and you medical students need to recognize the chest x-ray findings. Again this is a potential

automatic fail if you blunder on this! Pay attention!

The chest film is taken with the patient in an erect position so that any air within the abdo-

men rises to the diaphragms. The air can then be recognized under the right hemidiaphragm

with a clear outline of the diaghragm above. The left hemidiaphragm can also have air under

it but with the stomach in this region, it is more difficult. Therefore just concentrate on theright side.

A pneumoperitoneum is pretty easy to diagnose but only if you spot it. The pitfall is concen-

trating on looking for abnormalities within the chest and forgetting to fully assess the dia-

phragm.

Here are some tips:

Look for the ERECT label on the film. This will trigger you into remembering the

reason for an erect chest x-ray

If you are struggling to find any abnormalities in your exam, before you say I can

find no obvious abnormality, just glance again at the diaphragm. It is acceptable

if you miss a small lesion within the lung, but its a disaster if you miss a pneu-

moperitoneum in the exam!

Remember other causes of a pneumoperitoneum include recent abdominal surgery

(laparotomy or laparosocopy). However this should not last for more then 24 to 48

hours post surgery.


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clinical cases: pleural effusion

A pleural effusion is an abnormal collection of fluid within the pleural space. Just like a

pneumothorax contains air within this space, an effusion contains liquid. There are many

causes for an effusion. Effusions can be described as small, medium and large (obviously!)

How to present: This is an AP chest radiograph of a female. There is a large concave ho-

mogenous opacity with a meniscus on the left. It occupies over half of the pleural cavity.

There is a smaller similar opacity on the right with blunting of the costophrenic angle. The

heart borders are lost. There are bilateral pleural effusions here.


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Pleural effusions are pretty easy to diagnose.

Here are some tips:

Think of fluid within a container, it will all sink to the bottom. The opacity will be

evenly distributed in its density.

Remember it is like glass in water, there will be a meniscus at the edges. This is

called the meniscus sign.

Large ones are very obvious and can be really concave in shape!

Smaller ones can be detected by looking for blunting of the costophrenic angles.

Blunting may not occur until about 200-400ml of fluid is present.

Large ones can cause the lung to collapse and / or he mediastinum to shift.

A common exam question from the evil examiner is to list the causes of a pleural effusion

so be prepared to answer it! Here is a quick tutorial:

There are many causes of a pleural effusion so instead of remembering a list, have a struc-tured answer by splitting them into transudates and exudates.

Transudate Exudate

- Low protein content (30g/l)

- Formed by increased hydrostatic pressure

or reduced oncotic pressure

- Formed by increased capillary permeability

Remember the failures of other organs: Think of the nasty stuff:

Congestive cardiac failure Malignancy

Liver cirrhosis (liver failure) Infection

Nephrotic syndrome (renal failure) Pulmonary infarction


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Here is another obvious example of an effusion

How to present: This is a satisfactory AP chest radiograph. There is a dense homogonous

opacity within the right lung filed with a meniscus (arrow). This appears to be a moderately

sized pleural effusion. There is also some blunting of the lest costophrenic angle. The heart

appears large.


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clinical cases: tumours

A chest x-ray is very good at picking up discrete opacities within the lung fields and assess-

ing their shape, size and distribution. This often gives clues to the underlying cause of the

lesionbenign or malignant. For your purposes, all you need is to presume any sinister

looking lesion is malignant. However it is useful to have a list of differential diagnoses if the

examiner asks you what else your findings could be.

How to present: This is an AP erect chest radiograph. There is a small opacity within the

left lower lobe. It is circular with an irregular outline. I can see no other similar lesions or

any other abnormalities. This is a solitary nodule. It may represent a neoplasm.


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Tumours can either be really obvious, with a film full of metastases or just one discrete

solitary nodule all ready to be missed by the untrained eye. It is important not to miss any-

thing within the lung fields but also remember that tumours may also be present in other

structures, not just the lung. In particular look for any sinister lesions within the bones.

Tips:

Describe any lesion you see in terms of size, density, shape and outline.

Remember a few differential diagnosis for a solitary nodule other than malig-nancy: hamartoma (benign tumour), granuloma (inflammatory post infection), AV

malformation, lung cyst. This will make you look pretty smart that you have

thought of other possibilities.

If you have multiple metastases, always consider where the primary cancer is. A

common question is which tumours metastasize to the lung?

Theoretically any tumour can spread anywhere but breast, kidney, testicular, gas-

trointestinal, lymphomas is a good list to remember.


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Some more examples:

How to present: This is a PA film. There are at least three large opacities on this film. Twowithin the right lung field and one on the left. They have the density of a soft tissue mass.

They are of similar size. They all have an irregular outline. Unfortunately these lesions may

represent pulmonary metastases.


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Another example:

How to present: This is a standard chest film. There are multiple lesions throughout the

lung fields or differing size and shape. There is also diffuse shadowing spanning centrally

towards the peripheries. This is a case of pulmonary metastasis.


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Oh dear, this is such a sad radiograph. I am sure by now you can come to the diagnosis.


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A hilar mass:

How to present: This is a PA chest film. There is an obvious mass within the right hilum.

It has an irregular outline and seems to extend outward to the periphery. It has the density of

soft tissue. There maybe an old fracture of the left clavicle but otherwise there are no other

abnormalities. Overall, this film may represent a malignant lesion, lymphadenopathy or an

infective source. I would suggest a lateral plain film or a CT scan may help us here.


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clinical cases: lobar collapse

When a lobe of a lung fails to get any air, it collapses. It is usually caused by an obstruc-

tion proximally which prevents the lung from being aerated (for example a tumour or for-

eign body). The lung can also collapse from outside pressurelike when a pneumothorax

compresses it. The collapse causes a loss of volume in the lung fields and there are charac-

teristic radiological changes of each lobe when it collapses on a chest x-ray. Observe:

How to present: This is a plain PA chest radiograph. There is reduced size of the right lungfield with the right lower lobe entirely collapsed. There is some reticular shadowing in the

left lower zone but otherwise there are no other major abnormalities.


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clinical cases: lobar collapse

Again when identifying a collapsed lung, it is useful trying to identify which lobe has col-

lapsed and also for a cause of the collapse.

Here are some tips:

Right upper lobe collapse:

The horizontal fissure will be pulled upwards

The hilum maybe lifted upwards

The right apex will have an increased density with sharp outline The mediastinum will shift to the right

Right middle lobe collapse:

The middle lobe is difficult to see on a PA view as it is small.

There is increased density lateral to the heart, producing a possibly silhouette

sign

Suggest a lateral view may help to clarify.

Left upper lobe collapse:

Similar to the right upper lobe but remember the left is bigger than the right

It is the oblique fissure moving superiorly (there is no horizontal).

The increased density will therefore be in the upper and mid-zones.

Right and left lower lobe collapse:

The oblique fissure becomes more steep.

There is a triangle wedge shape behind the heart shadow.

The hilum maybe pulled downwards


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clinical cases: pneumonectomy

Pneumonectomy (surgical excision of the lung) provides an interesting chest film. It is one

of the causes of complete white out of the removed lung. It is always interesting to see medi-

cal students struggle with a compete white out of the lung field. They just gape and point it

is white and then make some unintelligible sounds.

How to present: A standard chest radiograph is shown. There is a complete white out of

the left lung field. The trachea is deviated to the left and the left hemidiaphragm is raised

(look how high the stomach bubble is). The right lung field is unremarkable. This case

would indicate a complete collapse of the left lung or complete removal of the lung with a

pneumonectomy.


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clinical cases: pneumonectomy

A pneumonectomy is not the only cause of a complete white out of the lung field (opaque

hemithorax). You must have a differential diagnosis when faced with such a picture in the

exam. The most important feature again is the mediastinum.

The mediastinum deviating towards the white out

Complete lung collapseif the main bronchus becomes occluded, the entire lung

becomes devoid of air, and like a brown paper bag, just collapses. No air = no

black on the x-ray!

PneumonectomyRemoving the lung means removing the air to that side! Obvi-

ously!

The mediastinum central

Severe pneumoniathis spells bad news for the patient unfortunately if their en-

tire hemithorax is consolidated.

The mediastinum deviated away from the white out

Large plural effusions, massive haemothoraxAny fluid building up on one sideof the lung will push all the other contents of the thorax to one side if it gets big

enough. Similar to a tension pneumothorax but with fluid (and therefore white, not

black on an x-ray).


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clinical cases: pulmonary oedema

Pulmonary oedema occurs when fluid from within the pulmonary vessels enters the inter-

stitium alveoli. The most common causes of acute pulmonary oedema are cardiogenic but it

can also be precipitated by other causes. Examples of this include infections, allergic reac-

tions, toxins (inhaled or circulatory), disseminated intravascular coagulation and over ag-

gressive fluid management. Here is an example of pulmonary oedema on a chest film:

How to present: This is a supine portable chest film. The film is inadequate as the costo-

phrenic angles are absent. There is increased vascularity throughout the lung fields with

batswing shadowing (black arrows) around the hila. There is fluid in the horizontal fissure

(white arrows). The heart is within normal limits. I am unable to fully assess for a pleural

effusion but certainly there is no gross one. The findings are overall consistent with pulmo-

nary oedema


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clinical cases: pulmonary oedema

Pulmonary oedema has some classical x-ray findings. It is a common question to list the

findings so here you go:

Kerley B lines (early signs of pulmonary edema) - 1-2cm horizontal lines seen in

the lower zones on the periphery of the lung field at the lung edge.

Butterfly or Batswing shadowingcentral prominence of the vasculature around

the hilum to look like a batswingapparently!

Fluid within the fissureslook closely at the horizontal and oblique fissures tosee if you can see them. They are straight long white lines

Upper lobe diversionthe superior pulmonary vessels seem to be far more pre-

dominant on the x-rays to appear all the blood vessels are diverting to the upper

lobes.

Pleural effusionsthere maybe small pleural effusions bilaterally

Cardiomegalyan enlarged heart would suggest a cardiac cause for the oedema


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clinical cases: cardiomegaly

Cardiomegaly on an x-ray is defined when the width of the heart is more then half the size of

the thoracic diameter. It is a simple diagnosis but it is important not to forget that AP or su-

pine films falsely enlarges the heart and therefore an accurate assessment can not be made.

How to present: This is a standard chest film. It appears slightly over penetrated. The obvi-

ous abnormality is an enlarged heart. There also appears to increased central shadowing, up-

per lobe diversion and very small pleural effusions. This is appears to be a case of congestive

cardiac failure.


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clinical cases: cardiac failure

Congestive cardiac failure is failure of the heart to adequately pump around the blood. This

leads to congestion and fluid seeping out into the tissues. At its worst in can cause severe

pulmonary oedema.

Here is another example of congestive cardiac failure on an x-ray:

How to present: This is a PA film. The heart is significantly enlarged. There is increased

haziness within the lung fields. There are small bilateral pleural effusions. There is also a

mass within the pleura of the left lateral lung field. The appearances suggest cardiac failure

with pleural thickening of an unknown origin.


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clinical cases: idiopathic fibrosis

Idiopathic pulmonary fibrosis is a progressive interstitial lung disorder of unknown origin.

X-ray changes are non-specific but tend to be abnormal in these patients. There is usually a

diffuse shadowing bilaterally at the bases and at the peripheries of the lung fields.

Observe the following x-ray:

How to present: This is an AP erect film. Although an AP film, the mediastinum looks

widened. There is diffuse bilateral reticular (intricate, resembles a net) infiltrates at the lower

zones and peripheries. The findings would be consistent with an interstitial fibrosis.


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clinical cases: cavitations

Cavitating lung lesions are often quite weird to view on a chest x-ray. They just do not lookright. It is like the lungs have eyes staring at you! Anyhow, there are many causes of cavi-

ties, the most common being an abscess, either developing from a pneumonia or from septic

emboli. Other causes include TB (infection), Wegeners granulomatosis, pulmonary infarc-

tion, infected bullae and neoplasms.

How to present: This is a portable AP semi-erect film. There are two large cavities withthick walls on each side of the lung field. The largest is on the left measuring 10 by 10 cm

and on the right approximately 5 x 5 cm. Furthermore there is consolidation of the right

lower zone. The trachea is deviated to the right. This picture certainly seems to have infec-

tive source, possibly a pneumonia with associated abscesses. I can see no fluid level but a

fully erect film may help us here.

Note: A fluid level within the cavity almost certainly suggests an abscess and is best ob-

tained with the patient erect.


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clinical cases: fractures

Fractures are easily missed on chest x-rays. This is either because they are not looked for or

simply that they are too difficult to see. Anyway, browse the following x-rays and spot the

fractures.

How to present: This is an AP erect film. It is satisfactory. There are no abnormalities

within the mediastinum, heart, diaphragms or lung fields. There is however a fracture of the

right clavicle.


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Spot the fracture:

How to present: This is a PA radiograph. It is satisfactory. There are no abnormalitieswithin the mediastinum, heart, diaphragms or lung fields. There is however fractures of the

6th, 7th and 8th ribs on the left hand side.

Look at the next page for the arrows to show you where the fractures are!


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The fractures:

Rib fractures are often difficult to spot immediately. Some people advocate turning the x-ray onto the side so it is easier to identify each ribs outline. It certainly does make it easier

but looks a little unprofessional!


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clinical cases: mastectomy

Sometimes even the subtlest features are the only abnormality in a chest x-ray. Observe:

There is only one breast shadow! The right breast is present, the left is missing. Otherwise

there is nothing too exciting about this x-ray (apart from half of it is missing!)

?


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present your findingspass the exam: 1

Presenting your findings is just as an important skill as reading the chest x-ray in the first

place. There is no point making the perfect diagnosis if you are going to stutter your way

through your findings.

Here are some tips of how to go through your presentation:

1. Be confident, look confident, not arrogant

You have to fool the examiner into thinking you have seen hundreds if not thousands of x-

rays before. You have to show him you are not afraid of what he has to show. Already by

reading this book you have seen quite a few x-rays, you should be pretty confident.

2. Careful with the word x-raySome examiners are very pedantic. They dislike the world x-ray when describing the chest

film. Be careful. When presenting, use the term radiograph or plain film. It will make

you sound good too! You will notice this book as interchanged radiograph, plain film and x-

ray. That is because we are not pedantic fools!

3. A good reliable start

An examiner often makes a quick impression of his prey, so you should have a reliable start

to support you. Always start with a presentation of the actual patient and film you are look-

ing at.

- This is an erect chest radiograph of a 23 year old lady, Mrs Bloggs

- This is standard PA chest radiograph of Mr Jackass, a 100 year old.

This buys you time, and you have made an impressive start already.

.


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4. Dont waste your time and his with the obvious

Do not spend too long on the basics. Quickly assess whether the film is adequately exposed

or rotated. Dont put your face next to the film to measure the distance between the medial

sides of the clavicles and dont spend ages deciding whether you can see the thoracic verte-

bra. It is unlikely you will get a poor film to assess in an exam so make a quick decision;

otherwise youll just annoy the man who is looking to fail you. Say for example:

- It is well exposed and well aligned

- It is satisfactory

- It is clearly overexposed

- Half the lung is missing from this film but I will assess what is available!

5. The most obvious abnormality

If you are confident that you have spotted an obvious abnormality, go straight for the money

shot. This is risky but rewarding. If you get it right, youre a hero, if you actually miss the

obvious abnormality, youre in trouble. One possibility is saying the following:

- The most obvious abnormality is . . I will also go through the rest ofthe film systematically to identify any other abnormalities.

If you cant see a clear abnormality, do not panic. Stick to your system. Say:

- There is no obvious abnormality. I will examine systematically to identify any

6. Dont come out with the diagnosis until the end

Be careful; try not to be too much of a hero. Do not say This is obviously lung cancer and

say nothing else. Describe your findings first, then at the end say the potential diagnosis.

For example:

- There is patchy consolidation in the right upper lobe, possibly consistent with

pneumonia.

- There is free air under the right hemi diaphragm consistent with a perforated vis-

cus


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7. Be familiar with the lingo

You have to show the examiner you have presented a billion times. Show him you are famil-

iar with his language. Do not say:

- There is white stuff in the top corner

- There is a circular thing in the middle

- The heart is big

- The trachea has moved!

Use terms like opaque, lucent, patchy, confluent, lesion, mass, deviated etc. It will make you

look good. Look at the clinical cases above for good terms to use!

8. Suggest further investigations

If you are doing really well or believe further investigations may help your uncertain diagno-

sis, by all means suggest them along with your reasons. The examiner may well tell you that

these investigations may not help, but it shows you are thinking. Please please only do this at

the end! Do not walk in and say A CT would be more beneficial! You will get thrown out!

9. Good luck

We hope with the above information, you will pass your clinical exam easily! All of us lazy

medical students need luck to scrape through. We hope your examiners are kind, good man-

nered and light hearted. May all the nasty examiners fall into a ditch and sustain a fractured

rib with a pneumothorax! GOOD LUCK SCRUBS!

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