How to Interpret a Chest X-Ray (Lesson 5 - Cardiac Silhouette and Mediastinum)

[@StrongMed]

There have been 3 questions/comments that have come up multiple times in the 9 years since this was posted: 1. Yes, there is an error @8:27. The pericardial and epicardial layers are switched. (Pericardial far is the anterior "cookie layer", while epicardial far is the posterior one.) Sorry, I wish there was a way to fix this without editing out that section altogether. 2. @1:45, the left and right lung are labeled and oriented that way (i.e. right lung on the left, and left lung on the right) because this is the universal convention for cross-sectional imaging in radiology: it's the view you would see if you were at a supine patient's feet and looking up towards their head. I know it feels unnatural for many people learning radiology - it felt unnatural to me too - but becoming familiar with that orientation will make CT scans that much easier later on. 3. Regarding the use of "dextrocardia" @10:26, in the US it is most common to use the term to only refer to the orientation/sidedness of the heart without directly imply anything about the intraabdominal organs. So while this particular person's gastric air bubble and relative hemi-diaphragmatic heights imply they likely have situs inversus (i.e. all internal organs are the mirror image of "normal"), the term dextrocardia still applies. This usage might not be the same in all countries and contexts.

[@osatal6340]

I love how he just roasted Oreo cookies ..."supposedly chocolate flavored discs" lool savage

[@StrongMed]

Errata: @8:27, pericardial and epicardial layers are switched. (Pericardial fat is the anterior "cookie layer", while epicardial fat is the posterior one)

[@raymondokeefe8433]

Hi Eric, You're a talented teacher and I thank you for the time and effort you have put into these outstanding videos. As a practicing nurse anesthetist, 17 years post graduation, the opportunity to review clinically significant anatomy and physiology has been a great joy, renewing my passion for the science behind what I do. Keep doing the good work for all of us out here in the trenches with you. Best.

[@manufonseca1464]

Internal med resident here, just wow! Cant believe i just found this videos. God bless you!

[@queziasink]

Thank you so much! No professor can be so clear like you ! ⚘❣

[@davidpowell3347]

At 2:35 the difference in the apparent size of the heart on the two films of the same heart is amazing.

[@StrongMed]

+MoSh (KZbin is not letting me directly reply to your comment...) I'm sorry but the CXR videos were created directly in Adobe Premiere, and it's cumbersome to export them into a non-video format.

[@chrow2188]

I believe your Dextrocardia film is full Situs Inversus. Gastric bubble and liver are swapped as well.

[@thebulgariankgbleade]

Chris R I was just about to say this. Diaphragm heights are also backwards. Either photoshoped and flipped, or full situs inversus.

[@xplanet2112]

I thought that too, or more that the marker is a post process applied one and that the view is indeed flipped. The marker looks like Kodak CR and it's possible that the cassette was put thru the processor AP rather than PA

[@amykowald9652]

Your video demonstrations are so helpful. Thank you for them. Also, I love the way you say "What is that?" in reference to the mitral valve replacement.

[@janinebuck8032]

NP needing to review for a job possibility. Have not had CXR reading for some time. Excellent, thanks so much for posting for us.

[@StrongMed]

@ambioct Yes, you are correct. Unless there are clues on the PA film, discerning RV enlargement from an anterior mediastinal mass on the lateral view can probably not be done reliably.

[@anapaulacintra2594]

Hi Eric , You´re an amazing teacher , thank you for sharing this precioues material with us.

[@luckypenny4263]

Excellent video!!! Please do more like this for pulmonary and the new LungRADS guidelines

[@zoraseslija4444]

Hello..I have one mistake to tell you ..on 2:24 there is PA and AP position of the patient...and the pictures isn't good because you flip the right and the left lung ..it should be on PA right lung on the right side..and on AP view too there is same mistake..

[@StrongMed]

I appreciate the comment! For this picture, I chose to use the same orientation as is done with chest CTs, in which the patient's axial cross-sections are viewed as if the observer was at the feet looking up towards the head. I agree that it initially seems to be a non-intuitive way to orient the images, but for better or worse, it's the convention used in radiology. For reference: w-radiology.com/chest_ct.php

[@zoraseslija4444]

I understand but here we are talking about chest XRay not CT.Never mind your videos are great and I enjoy watching them.

[@kamalpreethara3233]

Very useful videos. helped me a lot in my medicine rounds. thank you

[@ruwanwickramaratna8273]

Thank you for taking the time to make these videos.

[@argonmed]

Excellent Study Aids Thank you Eric Continue Your good work

[@ssywenki]

Thank you Doc.....I'm finishing up NP school.....very helpful:)

[@shivanichauhan1044]

very nice

[@doctorasifali]

Excellent effort with matching presentation...

[@mostafakoohi5165]

I think the image of dextrocardia in minute 10:25 was in fact "seitus inversus" because the gastric bubble was in the right side too In dextrocardia is the heart in the right side but gastric bubble is in the left and all of other structures are normal

[@StrongMed]

Agree with your impression that this patient likely has situs inversus. In common usage in the US, "dextrocardia" only refers to the state of the heart's orientation. It doesn't imply anything about the remainder of the body.

[@albertpirehzad6402]

Thank you for all helpful lectures and GOD BLESS.

[@gurudattthakkar]

Nice simplified explanation. Agree with Strongmed comment on dextrocardia

[@epilepsyawarenessaidresear930]

Thank you so much for this very informative and enriching lecture ❤️

[@TheCriticalCarePractitioner]

Would love to know the process you go through to make these EXCELLENT videos. Maybe you could make a video on that?

[@sajivgk]

@10:26, in the film showing dextrocardia, the gastric air bubble under diaphragm is on the right side .Is that the way it is supposed to be?

[@StrongMed]

The patient likely has full situs inversus, in which the entire body is a mirror image of "normal". There's a difference of opinion as to whether the term "dextrocardia" should be reserved for only those patients in whom the heart developed on the opposite side but the rest of the body is more-or-less normal, or whether "dextrocardia" implies nothing but the orientation and sidedness of the heart. My impression has always been that the latter usage is more common in the US; it might be different where you are learning/practicing, but it's also just semantics either way.

[@HMS20th]

Is the pericardial cyst in 14:00 anatomically extending into the left hilum ? I think so depending on the hilum overlay sign

[@DoDivinity]

Thank you Eric.… Quite helpful videos you've got here

[@mohammadghani6835]

Thank you Sir for the nice presentation.

[@coldmagnet]

Supposedly chocolate flavored discs.... this is why I keep coming back, Strong Medicine.

[@pirasa5]

I think in the oreo cookie sign section, you have misnamed epicardial fat. That should be paracardial or extracardiac. Epicardial fat stays under the inner serous layer of pericardium. Very nice videos. Thanks a lot for your efforts.

[@StrongMed]

Thanks for the comment! Unfortunately, there's no way to fix the Oreo mistake without taking down the video and reuploading, which will result in the vid restarting at the bottom of the search algorithm results (i.e. no one will find it anymore). I probably should have fixed it right away...

[@ayoobewonders5287]

12:10 Why the lobe of the lungs and the heart ventricle swap position?

[@lackygirl1234]

10:33 abnormalities od the mediastinum and hila

[@mahmooodxr]

Thank you Eric ... Excellent demonstration.

[@IRANI8448]

Thank you very much. You teach very clearly.

[@JuhiMittal]

hey, In the oreo cookie sign of pericardial effusion--epicardial fat is between the the visceral pericardium and epicardium, while the pericardial fat is in the pericardial space) .So, why is not the "posterior chocolate layer" epicardial fat since it is closer to heart .And " anterior chocolate layer" pericardial fat (since pericardial fat should be away from the heart). I am having bit of orientation problem.??Please help! Thanks a lot! :)

[@arnoldshoartzeneger2748]

I'm med stu in iran your videos very very useful thank u very much

[@sylvandude1]

in looking at the diagram I believe the lungs are labeled backwards??? when you demonstrate the size of the heart in ap and pa, aren't the lungs labeled wrong? I am kind of confused?

[@StrongMed]

The view that shown in that diagram (1:15-2:30 or so) is a typical axial cross section through the mid thorax. Convention in radiology typically has the orientation of this view as if the observer is looking at the cross section from the patient's feet. This seems counterintuitive for trainees starting out, since logically, one would expect the left lung to be on the left and vice versa. My guess is that the convention is this way to make comparison of CT scans (which include similar axial cross sections) with X-rays incrementally easier, since the right lung is on the left and vice versa with X-rays as well. And the reverse orientation with X-rays is such so that the film mimics looking at the patient from the front as if the X-ray interpreter were examining the patient. I understand this may seem unusual, but getting used to these types of views/orientation will make reading films (particularly chest CTs) easier in the long run. Hope that clarifies!

[@StrongMed]

***** I completely understand that the views feel non-intuitive (particularly the schematic on the right side of the screen), but I assure you the labeling is correct. At 2:25, on the lefthand of the screen is a schematic of a standard axial cross section view, whereby the patient's left is on the right side of the picture, and the anterior side of the patient is on top. This view makes more sense in CT imaging where the patient is lying down at the viewer is looking up at the patient from the vantage point of the feet. Even though this view/orientation is less obvious when you are imaging a patient who is standing, I stuck with it to be consistent with axial cross sections as displayed in CTs, and in anatomy textbooks. On the right side of the screen, it's the same schematic of the body on the left, but just rotated 180 degrees around an axis perpendicular to the screen such that the patient's anterior side is facing the bottom of the screen. If you still are unconvinced, it's easier to visualize if you take a model of a person (a kid's action figure, for example) and literally hold them up to the screen, body perpendicular to the screen, and rotate the person face up and face down. Another way to think about it is that the bulk of the heart should usually be to the left of the midline, and the right ventricle should always be anterior to the left.

[@MrStaunfenberg]

Although how can differentiated/distinguish between opacities în lower posterior mediastin and opacities in lower lobs of the lungs ?? Or between opacities in mediastin and opacities în pleura ??

[@오하나-i2e]

Thank you,sir. Fascinating!

[@PrashanthPandian30]

If u could make a pdf of this, it would be amazing to revise whenever we want... :/ Nevertheless, thank you for the tremendous effort...

[@sokvisuthros2634]

For the picture the middle mediastinal mass, I didn't see any clear boundary between the mass and cardiac silhouette. May you precisely point the dot lines over that boundary ?

[@superbesli8016]

Thank you, for this perfect presentation.

[@sajivgk]

@1:45 the right and left lung in the picture marked wrong i think. shouldn't they interchange?

[@StrongMed]

The image is oriented the same way as cross-sectional imaging (e.g. CT thorax) - as if you are looking up at a patient's head from the feet. It feels a little unnatural to many people at first, but the convention has been in place for decades.

[@sajivgk]

@@StrongMed thank you so much for your reply sir. Its a new information for me.

[@OngWeeKiat]

At the part where you talked about dextrocardia, why is the gastric bubble on the right side and why the left diaphragm is higher than the right?

[@StrongMed]

There are a large number of abnormalities with the "sidedness" of human anatomy. For example, on one extreme is situs inversus, in which the entire body is the mirror image of normal. So the heart, stomach, and spleen are on the patient's right, and the liver is on the patient's left. That's what is shown in this X-ray. There are other people who have only the mirror image of normal above the diaphragm, and those who have only the mirror image below the diaphragm. And there are even patients who seem to have developed from 2 left sides or 2 right sides! Detrocardiaa refers to any variation in which the heart has ended up on the right side of the thorax during development, with or without other congenital abnormalities.

[@OngWeeKiat]

That was a quick reply. I see, thanks for the info!

[@caterscarrots3407]

Isn't the mediastinum the whole chest cavity(for example if the heart takes up 50% or more of the mediastinum the patient might have myocarditis), not just the pericardial cavity.

[@DzmltMlpage]

Thank you sir , your far too kind , can i ask yyou if there are some way to tell if the chest x ray is AP or PA ( beside the cardiaque silhouette ) i mean what if the person have a cardiomegaly hwo we can tell if it's a PA or AP ?

[@mehediforever]

Thanks. Great video.

[@Ahmedte-f3m]

Hello, how are you? I have a question, please, what are the materials that x-rays cannot penetrate❤❤

[@TheCriticalCarePractitioner]

Would love it if you could do the same for the abdo film?

[@StrongMed]

Thanks for the suggestion! I'll put together 1-2 videos on abdominal X-rays once I'm through chest X-rays and a couple other topics I've promised viewers.

[@TheCriticalCarePractitioner]

I also struggle to understand the relationship between the various anti coagulants and the measurements to assess their effectiveness e.g. Warfarin, inr, aptt etc. wondered if that is something you could cover?

[@StrongMed]

JAWN DOWNHAM Yes, although I generally dread hematology, due to many requests for it, anticoagulants (and the process of hemostasis in general) are on the short list for upcoming videos.

[@TheCriticalCarePractitioner]

Fantastic...thanks once again Eric. Really enjoying the xray series.

[@calvinkkw]

Hi Eric. I have heard about Kartagener's Syndrome in which dextrocardia is accompanied by situs inversus and bronchiectasis. I am wondering if the film you showed in this video is consistent with Kartagener's Syndrome? Because I found a gas bubble below the right side of the diaphragm, absence of gastric bubble below left diaphragm and the left diaphragm is higher than the right (corresponding to the position of liver on left hand side instead of the left). Thanks! Your videos are excellent!

[@StrongMed]

calvinkkw, it's possible that this person has Kartagener's syndrome, though without any clinical history, I would say probably not since the bronchiectasis usually leads to chronic lung infections which normally lead to various abnormalities on the chest X-ray which aren't seen here. While there probably are adult patients out there with Kartagener's and unremarkable lungs on chest X-ray, I wouldn't expect it to be common. (Though all patients with Kartagener's have abnormal lungs when examined with chest CT.)

[@calvinkkw]

Eric's Medical Lectures Eric, thank you very much for your reply. Though it is not possible to confirm Kartagener's Syndrome in this case, is it possible to confirm situs inversus by the facts of presence of gastric bubble on right side instead of the left and elevated diaphragm on left side? Thank you very much!

[@StrongMed]

calvinkkw I'm so sorry, I'm just seeing your follow-up response now! To answer your question "is it possible to confirm situs inversus by the...presence of the right-sided gastric bubble"? Yes and no. Clearly there is something amiss in the abdomen, but without more complete imaging (i.e. CT scan) it's impossible to say whether the patient as true situs inversus (i.e. everything is switched left-right) or something called situs ambiguus - in which different organs are in different places without any discernable pattern that's clearly relatable to normal left-right orientation. In other words, situs ambiguus is sort of like the patient is somewhere in between normal (a.k.a. situs solitus) and situs inversus. Sorry again for the extreme delay!

[@MikeBirkhead]

To add to that, our radiology lecturer stated that it's so rare to have situs inversus, when you see it on CT or X-Ray, your first response should be to make sure the technologist didn't misplace the right and left markers (which is about equally common as situs inversus).

[@StrongMed]

Mike Birkhead I completely agree. It's like when you see a young healthy person who has an EKG showing an extreme QRS axis. Extreme axis is so rare that the majority of these are due to limb lead transposition. Or more generally, whenever any test comes back with a highly unusual and unexpected result, the first step is always to double check the data.

[@rajendrakumarsinghmehra2368]

Thank you sir , excellent presentation

[@rajdatta8428]

I may be wrong but I thought that in double density sign,the outer border is formed by the left atrium and inner border by right atrium...while talking about the double density,the narrator has said the opposite.. can we please have some clarity on this issue?

[@StrongMed]

Thanks for the comment. I actually think I got it right - at least, it agrees with this article from Radiopaedia.org: radiopaedia.org/articles/double-density-sign-left-atrium, and seems to also concur with the only primary literature article I could find that discusses it: www.ajronline.org/doi/pdf/10.2214/ajr.130.2.251. Occasionally, the left atrium can be so enlarged that it extends beyond (i.e. rightward of) the right atrial border, but this is not common. Let me know if a different reference states otherwise!

[@andrei4jesus]

Very informative. Thanks a lot !

[@r0drigues85]

Excellent lessons but you made a small mistake... It's a situs inversus instead of dextrocardia ( gastric bubble Is present on the right side and the liver is on the left side). Thanks and keep up the good work

[@giobasta6918]

Eric's Medical Lectures it is the same all over the world I am afraid. =) Greetings from Europe

[@r0drigues85]

My mistake... You are right, situs inversus with dextrocardia. Thank you for your clear explanation. Regards

[@r0drigues85]

And sorry, I should have written "I think you made a mistake.." ehehe

[@MrGouseustad]

Very well explained

[@bharathidhasan4725]

Nice video.Thank you

[@puneetsandhu9999]

how can we objectively define hilar enlargement? how do we know when big is too big?

[@sara-wm1zn]

can i get what explain in those videos written ?

[@Kuromeuphoriczz]

I have an issue with breating bc of health anxiety (i went to a doctors, ekg, radiology for my lung and my heart and its all fine) , its been better now since im not looking up a symphtoms in google and stupidly diagnosed my self with lymphoma and then this showed up with the thumbnail said "Lymphoma" and yeap my anxiety gets triggered, i watched the whole video bc curious and also scared, and now its hard to take a deep breath again but its okay i hope it goes away again. All i need to do is relax...fuck man i cant be a doctor

[@sebbyyoutube5564]

When you discussed the difference between PA and AP, were the lungs sides labelled the opposite?

[@StrongMed]

If you are referring to the diagram @1:30, the lungs are labeled as intended. Axial cross-sectional imaging in radiology is displayed as if you were standing at the foot of a supine person and looking up at their head. For example, all CT/MRI scans are oriented this way ( mrimaster.com/anatomy%20chest%20axial.html ). I would agree that this orientation is not intuitive when first learning imaging, and I don't know why this convention began. But it is universal.

[@danielrochin9655]

Dude, you rock!

[@stephenfajemilehin6657]

very helpful, thank you.

[@drnsharanMS]

Brilliant. Thank you

[@md.tawfiqulislam8876]

can u plz share the slide as pdf????

[@StrongMed]

The chest X-ray video series was made using a different technique than most of the other videos on the channel, which unfortunately does not lend itself to easy conversion to a pdf format.

[@raheemprime6860]

it really helps a lot 16/12/2017

[@cathy761]

Fantastic!!!

[@drabhaydhage7478]

excellent--thanks

[@niamatullah4442]

Sir thanks.. appreciated

[@محمدأنور-ه4ب]

really strong medicine!

[@srinivasaraosirasapalli5104]

excellent

[@sthrallday]

very well done! thanks

[@qiqisongs]

I like your videos. Just wanna ask, isn't the pericardial effusion surrounded by pericardial fat anteriorly and epicardial fat posteriorly?

[@StrongMed]

Yep. That's an annoying mistake I made that I didn't catch for a while. Have spent the last 2 years wondering if I should take this video down, fix it, and repost it with the view count starting over at 0, or just leave it up since it doesn't actually impact making the diagnosis and hoping that most viewers realize the mistake on their own.

[@shanvel1417]

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[@kadabentata1866]

Excellent

[@elenakennebury2192]

thank you very much

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Thank youuu so much 12/11/2017 ✨

[@dr.imranrasheed4103]

Excellent.

[@abdulmajeedalmutairi1002]

thanks

[@benben90b]

thank you

[@ramdankhan]

EXCELLENT thanks a lot

[@riritan798]

Many thanks

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감사합니다 :)

[@NiTeLightYears]

10:00

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10/1/22

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