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Lunate dislocation…

September 30, 2014

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This patient presented with wrist pain after a fall:

 

Lunate 1Lunate edits

This is an example of a lunate dislocation.  The lunate can be seen on the lateral view (blue arrow).  It is dislocated quite a far distance.  Also note that the lunate is not in its usual location on the AP view.

The above radiographs are not subtle.  Keep in mind that lunate dislocation is sometimes not so obvious.  We visited lunate and perilunate dislocation on a prior post (lunate).  Stay tuned in the future for tips on reading wrist radiographs to avoid missing any subtle injuries.

Author:  Russell Jones, MD

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How to identify a cardiac rhythm device with CXR…

September 25, 2014

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How many times have you had trouble with figuring out what type of cardiac device (e.g. pacemaker/defibrillator) a patient has implanted?  A patient presented to our ED with chest pain, palpitations.  He did not have his device card with them, no prior visits to our ED, and did not know the manufacturer of the device.  How do you decide which company to call for interrogation?

Here is an article I found with radiologic characteristics of devices that can help identify which company produced the device.  It has a great identification algorithm they coined the CaRDIA-X algorithm:

http://www.ianchristoph.com/physician-resources-2/device_id.pdf

There are 5 major manufacturers currently:  Medtronic, Boston Scientific, St. Jude, Biotronik, and Sorin Group.  Each device manufactured by these companies have certain differentiating characteristics of can shape, battery shape, alphanumeric codes, capacitor shadows, coil types, etc.  Turns out you can identify the manufacturer using the device characteristics on chest X-ray relatively easily.

In the case I was describing above the patient had an easily identifiable Medtronic device and we were able to get it interrogated.  Our ED now has the algorithm posted at our doctor’s station so we can utilize it for device identification.

Author:  Russell Jones, MD

References

Jacob S et al.  Cardiac Rhythm Device Identification Algorithm Using X-Rays: CaRDIA-X.  Heart Rhythm 2011; 8(6): 915-922.

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Acromioclavicular separation…

September 15, 2014

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This person fell from bike and won’t move their shoulder:

AC separation 1 AC separation 2

On initial evaluation we actually thought this person had a shoulder dislocation (glenohumeral dislocation) because of the significant deformity visible externally.  They had the classic anterior “divot” on the shoulder and wouldn’t perform shoulder range of motion.  We were somewhat surprised when we found an acromioclavicular (AC) separation instead.

This case is a good argument as to why often it is appropriate to obtain pre-reduction X-rays for possible shoulder (glenohumeral) dislocations.  Unless the patient will allow a good exam, sometimes it is very hard to differentiate AC separation from glenohumeral dislocation without imaging.   In this case, if we went directly to attempted “reduction”  it would have been very difficult to “reduce” the shoulder!  Hence the need for an X-ray.

There are six different types/degrees of AC separation that are summed up well on the following LearningRadiology.com webpage:

AC Separation Types

 

Author:  Russell Jones, MD

References

1.  Acromio-clavicular separation.  www.LearningRadiology.com

 

 

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Student Corner: How to Read a Chest X-Ray Follow Up

September 1, 2014

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Here is the same CXR from last time.

 

CXR UL pna

Here’s some further information about the case:

Pt is a 52 y/o man with a history of smoking, atrial fibrillation, and HTN that presents to the ED today with a 2-3 day history of fatigue, weakness, fever, generalized body pains, drenching night sweats, increased urinary frequency, L ear discomfort, throat discomfort and blurry vision in the morning. The symptoms came on suddenly and have been constant since the beginning of the episode. The fatigue and weakness cause the patient to want to “drop into a hole” and sleep. His nightly sleep patterns have been disrupted by his night sweats and his increased urinary frequency. The night sweats are drenching and he often wakes up in the middle of the night with his shirt completely soaked. Around 8-9 AM in the morning he reports being cold and getting chills. He also has some lower sternal chest pain that occurs mostly with deep breathing. The pain does not radiate. The pt has a 30-35 year history of smoking cigarettes and drinking 15-20 alcoholic drinks/week. The pt stopped smoking yesterday with the intent to quit.

The pt has no change in appetite or weight, no new masses or lumps anywhere on his body and no syncope or LOC. The pt denies any history of similar symptoms. The pt denies any family history of these symptoms. The pt denies any sick contacts. The pt’s wife does not have similar symptoms. The patient has no N/V or history of recent travel. The pt was routinely tested for tuberculosis 2 years ago as part of an employment physical and the test was negative.

Vitals: BP 142/106 | Pulse 105 | Temp(Src) 100.6 °F (38.1 °C) (Oral) | Wt 228 lb (103.42 kg) | BMI 31.36 kg/m2 | SpO2 99%

Physical Exam: 

General appearance – alert, well appearing, and in no distress; slightly pale

Eyes – PERRLA, EOMI

Ears – bilateral TM’s and external ear canals normal

Mouth – mucous membranes moist, pharynx normal without lesions

Neck – supple, no significant adenopathy

Lymphatics – no palpable lymphadenopathy, no hepatosplenomegaly

Chest – clear to auscultation, no wheezes, rales or rhonchi, symmetric air entry

Heart – normal rate, regular rhythm, normal S1, S2, no murmurs, rubs, clicks or gallops, no pericardial rub on auscultation with patient leaning forward

Abdomen – mild suprapubic ttp without rebound/guarding

Neurological – alert, oriented, normal speech, no focal findings or movement disorder noted, CN 2-12 grossly intact

Skin – normal coloration and turgor, no rashes, no suspicious skin lesions noted

With all of that in mind, let’s take a look at the x-ray again. The last post went through the ABCDE methodology to review the image and the A through D aspect was pretty well outlined there. The airway is patent, there is no obstruction and it lines up with the cervical spinous processes. The bones have no step-offs or other evidence of fractures and there are 10 ribs visible. The cardiac silhouette is not enlarged (in other words, not more than twice the width of the chest cavity) and the AP window sits between the aortic arch and pulmonary artery. The diaphragm has normal contour and the costo-vertebral angle is sharp.

The E is where things get interesting. One of the ways I like to do it is to try and look for asymmetry in the lung fields. And I think I see something!

CXREXoriginal-finalread

The blue circle seems like a focal area of consolidation (either liquid or solid). That same “opacity” is not present on the corresponding place on the L lung field.  I think its important to note that this finding has a large differential diagnosis attached to it, even if you put the finding on the x-ray in context with the case presentation. Most of the diagnoses on the list would be infectious, like TB or pneumonia, but other possibilities include lung cancer, edema, hemorrhage and systemic inflammatory conditions like sarcoidosis.

The radiologist read that image as most likely a case of lobar pneumonia. There was some hedging by the radiologist on the read because the lateral film was taken from L to R, therefore the opacity in the R lung field was very hard to see (that’s why I didn’t include a lateral view as well, but we can save that particular x-ray type for another post). In general, you want to get two views on any pathology on x-ray because it’s important to try and construct a 3D image in your head about where the pathology is located.

In any case, his patient presented with fever, cough, loss of energy, chills and body aches, with all of those symptoms having an acute onset. This makes an infectious process more likely (I say “more likely” because as everyone in medicine learns at some point or another, it is very dangerous to talk and think in absolutes). He was treated empirically with antibiotics for pneumonia.

Hopefully this example helps you to have a system in place when you look at any chest x-ray. If you have any questions, feel free to drop them in the comments and I’ll do my best to answer them.  Also, if you have any requests for certain types of images you would like to see for the next post, also let me know in the comments. Until next time!

Author: Jaymin Patel

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Student Corner: How to Read a Chest X-Ray

August 25, 2014

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In these “Student Corner” pieces, we will go over certain aspects of radiology in EM that are of interest to medical students. Topics will include: common (and interesting) case presentations with accompanying imaging, schematics for how to read different types of imaging in various anatomical locations, discussions on what types of imaging to order and when in the EM setting, and others.

In this inaugural edition of the Student Corner, we’ll take a look at how to tackle reading an anterior-posterior chest x-ray.

For starters, it is important to understand that having a “gameplan” for reading any type of image is key when you first start out trying to decipher radiological images. As a reader and interpreter, you must be systematic in your thought process as you analyze the image in front of you. For chest x-rays, there is a classic schematic: ABCDE. Any medical student will tell you that this is not the only time you will see “ABC…” used as a way to quickly memorize something, but at least it’s easy to remember.

Here’s the image we are going to use and let’s start to dissect it using the mnemonic:

Note: For the purpose of keeping this a short piece, we’ll only focus on the anterior-posterior view only.

CXR UL pna Airway

A-Airway

Legend: Red Arrows–trachea; Blue Arrows–carina; Green arrows–L and R main bronchus

The upper airway, including the trachea, carina and both main bronchi, should all be visible on an AP view. Things to look for include deviation of the trachea away from the midline (there is some deviation to the patient’s right in this image, but this is due to the aortic arch, which passes to the left of the trachea as it passes posteriorly in the mediastinum), obstruction due to aspiration of a foreign object and obscuring of the upper airway due to enlarged mediastinal lymph nodes.

Let’s explore tracheal deviation a bit further. Deviation from the midline is not associated with a defect in the trachea itself, but with a force from either the R or L side of the chest cavity that is pulling or pushing the trachea to one side or the other. For example, introduction of air into one side of the chest cavity will cause that lung to collapse due to the loss of negative intrapleural pressure. The collapsed lung will shrink to the size of a ball and “push” the trachea to the opposite side. You can think of the two lungs like bungee cords that put roughly equal force on the trachea in each direction. If one of the cords snaps or is released from where it is attached to, the cord that is still intact will pull the trachea towards one side, resulting in a deviation that will show up on a CXR.

B-Bones

CXR example Bones

Legend: Numbers–ribs; Red Arrow–clavicle; Blue Arrow–medial border of scapula

A CXR offers a good view to look for rib fractures and clavicle fractures. Clavicular fractures are usually easy to spot, as they usually reveal distinct fracture lines in the middle 3rd of the clavicle. Hairline fractures are less common. Rib fractures are sometimes hard to spot, but each rib should be followed across it’s length to look for fracture lines or step-offs (disruptions in the normal curve of the rib) that could indicate a fracture.

The number of ribs is also important to assess because it is an indirect measurement of the volume of the chest cavity. Hyperinflated lungs are usually the result of obstructive disease where the patient is unable to fully expel the air that is inhaled with every breath they take–this increase in residual volume will build up over time and overinflate the chest cavity. This overinflation will result in a greater-than-normal number of ribs being visible on an AP view. Normally, you should expect to see 8-10 ribs on an upright chest X-ray, depending on whether the patient was instructed to exhale or inhale before the picture was taken.

C-Cardiac

CXR Cardiac

 

Legend: Red Dashed Lines–heart borders

This part of the mnemonic involves the heart and surrounding structures. The silhouette of the heart should be identified and the heart borders should be clear. A general rule of thumb is that the heart base should not be wider than 1/2 the total width of the diaphragm. As with a lot of “general rule of thumb”s in medicine, it’s not quite clear whether this has any diagnostic value–for example, if the heart base is indeed 1/2 the width of the diaphragm on CXR, is that really sensitive for cardiomegaly? In any case, it’s something to keep in mind.

The aortic arch and the L pulmonary artery should be visible as two semi-circles above the left atrium. There is a space called the “AP Window” that has the following borders: ascending aortic arch (anterior), descending aortic arch (posterior), L pulmonary artery (inferior), inferior border of aortic arch (superior). The window should be “concave” in the sense that the lateral border should be caved in medially. If it is not, things like mediastinal lymphadenopathy and aorta/pulmonary artery aneurysms are possible.

D-Diaphragm

CXR Diaphragm

 

Legend: Blue Arrow–gastric air bubble; Red Arrow–costophrenic angle

The diaphragm has 3 major characteristics which you look for on CXR. One is the gastric air bubble, which allows you to identify that the stomach is on the left (as opposed to the right, as in situs inversus). Another is the contour of the diaphragm, which should be a “dome” shape. The right side should be a little higher than the left, thanks to the liver. The third is perhaps the most important: the costophrenic angle. It is the lateral point of attachment for the diaphragm and it should be a sharp, triangle-shaped region at either end. The angle should be acute. If the angle is closer to 90 degrees, then one possible explanation is that the lungs are hyperexpanded (perhaps because of COPD) and pushing the diaphragm down into the abdomen. “blunting” of the angle refers to a radio-opaque marking of the angle that usually is indicative of pleural effusion.

E-Everything Else

Everything else is…everything else. Mostly this means the lung parenchyma itself. For this, asymmetry is key. Compare left and right and see whether there is a difference. More on this particular section of the read later.

—–

Now you should try to read the above x-ray for yourself and type your own version of the read in the comments if you’d like. If not the entire read, then try to identify the pathology in the x-ray and post your answer in the comments. Any questions/comments would also be appreciated.

I’ll post the answer with the “correct” read a bit later on the site.

Author: Jaymin Patel

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Maisonneuve Fx…

August 14, 2014

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This patient presented to the ED after twisting their ankle playing basketball.  Notably on clinical exam the patient also had pain to palpation near the proximal lower leg:

 

Massoneuve Fx 2

Massoneuve Fx 3

These radiographs show two clearly visible fractures on the proximal and distal fibula.  Also noted is some widening of the mortis on gravity stress view and if you look closely on the anterior tib/fib image (top) there is a comminuted proximal tibia fracture.  The injury pattern seen here is an example of a Maisonneuve type fracture.

A Maisonneuve fracture occurs when with disruption of the distal tibiofibular syndesmosis is associated with a proximal fibular fracture.  Often a medial malleolar fracture will be seen as well (not in this image).  This is an unstable fracture pattern that often needs operative intervention.  This image has an additional proximal tibia fracture that isn’t usually classic for a Maisonneuve fracture pattern.

In order not to miss this fracture one should always perform a proximal lower leg exam with all ankle injuries!  Image the entire fibula if there is pain.

Author:  Russell Jones, MD

 

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What are these devices? Answer…

July 31, 2014

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Question earlier this week:  “There are two devices entering the mediastinal structures from below…what are they?”

IABP 2

iabp-2

There are a bunch of devices on this radiograph.  Here they are by color:

1.  Orange arrow:  A Swan-Ganz catheter coming up from the femoral vein

2.  Red arrow:  Intra-aortic balloon pump coming up from the femoral artery

3.  Green arrow:  External monitor cables extending to the various monitor points on the patient externally

4.  Blue arrow: Dialysis catheter coming from the right internal jugular vein

Admittedly, this is not your usual ED-based radiograph.  This patient was presented with a STEMI and in cardiogenic shock.  This was a radiograph obtained later in the cardiac ICU after coronary intervention.  The Swan-Ganz catheter is unclear if it is in proper position (pulmonary artery).  Usually Swan-Ganz catheters (AKA pulmonary artery catheters) are placed from the superior circulation and loop into the pulmonary artery.  This was placed under fluoroscopy while performing a coronary artery intervention in the cath lab; I’m not sure where the tip is located based on this radiograph.

Author:  Russell Jones, MD

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What are these devices?

July 28, 2014

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There are two devices entering the mediastinal structures from below…what are they?

IABP 2

 

Answer to follow!

Author:  Russell Jones, MD

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Not your ordinary arm fracture…

July 21, 2014

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This patient was shoveling, had sudden onset of forarm pain…

Radius fx 2 radius fx

This is a pathologic fracture from a forearm malignancy.  The patient’s primary malignancy was rectal adenocarcinoma.  This is a rare place for a metastasis.

The mechanism for this patient did not support a broken bone.  However one should keep in mind pathologic fractures when deciding whether to obtain plain films.  Plain films in the ED are quick, inexpensive, and don’t come with significant radiation risks.  I usually argue these points with my residents when discussion about plain film utilization in musculoskeletal pain.

Author:  Russell Jones, MD

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WWWTP #17 Answer…

June 30, 2014

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This is a pediatric radiograph of a patient with wrist pain after a fall:

SHII fx distal radius II SHII fx distal radius

 

There is a subtle linear lucency on the distal radius, best seen on the lateral view.

This is a Salter-Harris Type II Distal Radius fracture.  For a refresher on Salter-Harris classification see:

Salter-Harris

Author:  Russell Jones

References

1.  Salter-Harris Fracture.  http://en.wikipedia.org/wiki/Salter–Harris_fracture

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