Transition Block B - Radiology Module - Interpreting CXR & Assessment Flashcards
What is the first thing you must do when checking a patients chest x ray?
You must check the patient’s name, date of birth and hospital number on the Xray
After confirming the patients name, DOB and hospital number to confirm it is the correct patients scan, what is the next thing you must do when analyzing the CXR and why?
Must check the date and time the CXR was taken as some patients have several on the PACs system (picture archiving and communications system)
Next make a technical assessment by checking the: * Side marker * Projection * Degree of inspiration * Centering (is the CXR rotated) What does this side marker show?
This side marker (the L) is either incorrectly labelled or the patient has dextrocardia
How could you check if this patient’s side marker has been wrongly labelled or if the patient has dextrocardia?
You could make the distinction between the two by palpating the patient’s apex beat
Next make a technical assessment by checking the: * Side marker * Projection * Degree of inspiration * Centering (is the CXR rotated) What type of projection do the best quality CXR use?
The best quality CXRs use a PA projection taken with the patient erect facing away from the xray source
Why are PA projections preferred?
CXRs taken PA are usually well inspired The scapulae only minimally overlap the lungs The heart size can be reliably assessed
Other CXR projections include AP, supine and lateral What is the problem with AP xrays?
AP - usually if patient is sick and unable to stand AP projections can exaggerate heart size as well as the scapulae overlapping the lungs - can simulate or mask disease
AP xrays can be carried out if the patient is sick and unable to stand However these xrays may exaggerate heart size as well as the scapulae overlapping the lungs - potential to mimic or mask disease When are supine xrays carried out?
Supine xrays can be carried out in patients who are two unwell to sit up - these xrays are also annotated by the photographer
What are the problems with supine xrays? (makes it difficult to diagnose different diseases (try name 2, both involve conditions where there is air where it shouldnt be and cant be seen properly on supine xrays)
Pneumoperitoneum (see image)- normally diagnosed using an erect CXR as gas rises to accumulate below the diaphragm - using supine CXR does not allow the gas to rise Pneumothorax - Pleural air is seen anteriorly adjacent to the heart rather than at the ape of the lung
Next make a technical assessment by checking the: * Side marker * Projection * Degree of inspiration * Centering (is the CXR rotated) How do you check if a CXR is adequately inspired?
On an adequately inspired CXR, 6 anterior rib ends should be visible above the left diaphragm
What is the importance of recognizing whether CXRs are well or poorly inspired?
Poorly inspired CXRs can exaggerate the heart size and the basal lung markings - this can simulate heart disease or lung base infection
Next make a technical assessment by checking the: * Side marker * Projection * Degree of inspiration * Centering (is the CXR rotated) After checking for a correctly labelled side marker, the projection of the CXR and the degree of inspiration - the final check is to look for centering and to see if the CXR is rotated * How do you check if the CXR is rotated?
To assess whether a CXR is well centered or rotated, you need to measure the distances from the medial ends of the clavicles to a thoracic spinous process
Is the CXR well centred if the distance between the medial ends of the clavicles to the thoracic spinous process are: * The same on both sides * Non-equal on both sides
CXR is well centred if the distances between the medial ends of the clavicles to the thoracic spinous process is equal on both sides If unequal the CXR is said to be rotated which can cause problems
Technical assessment - remember (side marker, projection, degree of inspiration, centered/rotated) It is of course difficult to obtain a perfectly centred CXR How does a little rotation affect diagnostic quality? How does a grossly rotated CXR affect diagnostic quality?
A little rotation doesn’t affect the diagnostic quality of a CXR A grossly rotated CXR can greatly affect diagnostic quality by exaggerating heart size or simulating a hilar or mediastinal mass Rotation can also cause the lun size to seem unequal leading to a misdiagnosis of lung disease
Describe the differences in the two xrays - nb both are actually normal but the rotation can lead to a misdiagnosis
Both CXRs are AP erect and well inspired The first Xray is rotated as the distance between medial ends of clavicles to thoracic spinous process is unequal - could lead to a misdiagnosis of left lower lobe pneumonia with displacement of the heart to the right
We have finished the technical assessment of the XRAY (side marker, projection, degree of inspiration, centered/rotation) NEXT we go through the pathological assessment of the XRAY EASIEST done systematically - ABCDE What do these stand for?
Airway Breathing Cardiac Diaphragm Everything else
CXR Name, DOB, Hospital Number Date and time taken Technical assessment Pathological assessment - ABCDE What are the main things examined in A?
Airway * Trachea * Carina and bronchi * Hilar structures
Airway * Trachea * Carina and bronchi * Hilar structures Where should the normal trachea be? What conditions could deviate the trachea?
The normal trachea should be central - if deviated, look for structures that could push or pull the trachea Push the trachea - this could be caused by a large pleural effusion or tension pneumothorax Pull the trachea - this could be caused by eg a lobar collapse
Airway * Trachea * Carina and bronchi * Hilar structures What level is the carina located? and what is it?
Carina is located at T5-T7 vertebrae - rib2 it is where the trachea divides into the left and right main bronchii
On a good quality CXR this division (the carina) should be visible and is an important landmark when assessing nasogastric tube placement, as the NG tube should bisect the carina if it is correctly placed (i.e. not in the airway). Why is it more common for foreign objects to be inhaled into the right lung?
This is because the right main bronchus is generally wider, shorter and more vertical than the left main bronchus - more direct route for foreign pathogens / objects
Airway * Trachea * Carina and bronchi * Hilar structures What forms the hilar shadows that are seen on the xray?
The hilar shadows are formed from multiple superimposed pulmonary arteries and veins
Where do the normal right and left hila lie in relation to one another?
The normal right hila lies 1.5cm below the left hila (this is because the right pulmonary artery is lower than the left and therefore the hila must be lower)
What can be said about the shape, size and density of the hila?
The hila have different shapes on CXR due to the configuration of the vessels However the size and density of the hila should remain similar
Any hilar enlargement or increase in density should raise suspicion What may bilateral hilar enlargement raise suspicion of? What may unilateral enlargement may suspicion of?
Bilateral hilar enlargement is typically associated with a bilateral hilar lymphadenopathy due to sarcoidosis Unilateral hilar enlargement may be due to underlying malignancy (see image)
Systemic pathological assessment of the CXR * Airway - trachea, carina/bronchi, hilum * Breathing - lungs and pleura * Cardiac * Diaphragm * Everything else Breathing - Lung density varies from apex to base, due to chest shape and overlying soft tissues. How do we examine the lungs?
We separate the lungs into zones Apices, upper, mid and lower zones The density of the zones varies from apex to base but should be the same between right and left lungs
Using the zone separation technique, can you spot if there is a disparity in zone density?
By comparing the lung zones, can see that the right lower zone is denser than the left lower zone pointing towards a potential right lung pneumonia (middle or lower lobe)
Systemic pathological assessment of the CXR * Airway - trachea, carina/bronchi, hilum * Breathing - lungs and pleura * Cardiac - size, border, position * Diaphragm * Everything else Cardiac What is the normal cardiac size?
The normal cardiac size measures 50% or less of the cardiothoracic ratio - ie should occupy no more than 50% of the thoracic width
When checking the hearts position, what should the normal position of the heart be?
One third of the heart should lie to the right of the sternum Two thirds should lie to the left of the sternum
Inspection of the heart borders on CXR should be normal in healthy individuals What forms the right and left heart border on CXR? What is loss of definition of these borders associated with?
Right heart border - right atrium - loss of definition associated with right middle lobe consolidation Left heart border - left ventricle - loss of definition associated with lingular consolidation
Chest disease can cause a shift in the diaphragmatic position eg so that the left hemidiaphragm is higher than the right What is an example condition that could cause this?
Chest diseases that alter thoracic volume may cause a diaphragmatic shift eg if there were a left lower collapse, this would cause the diaphragm to rise, and also may cause the heart to shift tot he elft
Normal costophrenic recesses contain a dark flange of lung with sharply pointed edge. Pleural fluid gravitates to these lung bases. What is the earliest sign of a pleural effusion?
The earliest sign of a pleural effusion is the obliteration of these sharp costophrenic angles - sometimes referred to as costophrenic blunting
What may ga under the right diaphragm raise suspicion of?
Gas under the right diaphragm would raise suspicion of bowel perforation and pneumoperitoneum Pneumoperitoneum due to bowel perforation - CXRs obtained supine do not reliably show as gas does not move to the diaphragm.
Systemic pathological assessment of the CXR Airway - trachea, carina/bronchi, hilum Breathing - lungs and pleura Cardiac - size, border, position Diaphragm - position, gas, costophrenic recess/angle Everything else - mediastinum, bones, tubes/valves/pacemakes Where does the normal aortic arch (knuckle) lie? What does it merge with inferiorly?
The normal aortic knuckle lies above the left hilum as it arches over the left main bronchus. It merges inferiorly with the descending aorta.
Lastly, before completing your assessment, always ensure you’ve looked at the ‘Review areas’ What are the review areas?
* Apical lung disease * Left lower lobe disease superimposed on the heart * Small pleural effusions * Free intraperitoneal gas * Shoulder pathology
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THIS FLASHCARD IS NOT A QUESTION - SIMPLY INFORMATION Silhouette sign is somewhat of a misnomer and in the true sense actually denotes the loss of a silhouette, thus, it is sometimes also known as loss of silhouette sign
Silhouette sign (loss of silhouette sign) RLL - right hemidiaphragm RML - right heart border LUL - left heart border LLL - left hemidiaphragm RUL - will explain in a couple of cards
This CXR represents a pneumonia. How can you tell which lobe is affected?
CXR is PA - well inspired and centered. Can see there is consolidation in the lower right lung zone. The right hemidiaphragm is obscured yet the right heart border is not and there is therefore a right lower lobe pneumonia.
The inferior margin of an opacified right upper lobe is often sharply defined due to what?
The inferior margin of an opacified right upper lobe is often sharply defined due to the horizontal fissue along its inferior margin This is a useful way of localising RUL disease on a CXR.
A CXR will confirm correct placement of various medical devices, prior to use. These include: Endotracheal (ET) tube Nasogastric (NG) tube Central venous line (SCV, IJV) Intercostal chest drain Cardiac pacemaker You should be able to recognise correct and incorrect line placement. * What is the correct position of a central venous line and an NG tube?
Central venous line tip should go from subclavian vein and into the superior vena cava just proximal to the right atrium NG tube tip should lie just below the diaphragm within the stomach
THIS FLASHCARD IS NOT A QUESTION - SIMPLY INFORMATION
THIS FLASHCARD IS NOT A QUESTION - SIMPLY INFORMATION Now continue flashcard assessment questions
A supine CXR is an unreliable way to diagnose pneumoperitoneum True or False
True - Using a supine CXR does not allow the gas to rise to below the diaphragm as an erect CXR would
The aortic arch projects above the right hilum True or false
False The aortic arch projects above the left hilum
The normal right hilum lies superior to the left hilum True or false
False The normal right hilum lies about 1.5cm below the left hilum
The heart, midzones and lung apices and are all recognised CXR review areas True or false
False Apical lung disease Left lower lobe disease superimposed on the heart Small pleural effusions Free intraperitoneal gas Shoulder pathology
