#radley irradiates people

[radioactiveradley]

It’s SPOOKY SCARY SKELETONS MONTH

So let’s talk about yer bones! Yeah, that’s right, Captian Holt. I said –

An adult has (roughly) 206 bones (I say ‘roughly’! You can have non-pathological anatomical variation, such as lumbarised sacral vertebrae (an extra bone in your back) or accessory sesamoids like the flabella (a little bone at the back of the knee!))

A newborn has (roughly) 300 bones

That's a big difference! Almost 100 bones of difference! Where do they go?

Well, you see - as you get older, every time you come into the hospital we steal more of your bones...

Just kidding.

...Or am I

As an embryo, your skeleton is completely composed of cartilage. This gradually ossifies as you age, until, as an adult, you have a full skeleton, with only the interactive portions of joints being capped with hyaline cartilage.

[Paediatric normal whole leg radiograph, showing epiphyseal plates around the head of the femur, the femoral condyles, the proximal tibia, the distal tibia and the lateral malleoli that can mimic fractures. Courtesy of radiopaedia]

See all those weird blobs? Those are bones in the process of fusing together! The transverse lines that could be mistaken for fractures are actually epiphyseal plates – hyaline cartilage bridges between the shaft of a bone and what will become its tip, which don't attenuate x-rays, and thus appear black on our radiographs! This is where bone growth occurs - the cartilage forms a sort of template matrix that then ossifies into bone.

Compare our paediatric radiograph to the AP knee radiographs of an adult with no visible pathology:

[Adult normal AP knee radiographs, showing fully fused bones. Courtesy of radiopaedia]

See how all those ragged pieces have joined up? That’s endochondral ossification, BABY!

This is how we can figure out the age of a paediatric service user from their bones! Certain bones form at different times.

Let’s check out the carpal bones – all those fiddly little bones in your wrist! Anyone who’s binged Hatecrimes MD – sorry, House MD as often as I have will know the classic acronym for remembering the names of these bones. Moving thumb side to pinkie side, we have…

Scared (Scaphoid - red)

Lovers (Lunate - dark blue)

Hate (Hamate - green)

To (Triquetrum - yellow)

Try (Trapezium - orange)

The (Trapezoid - light blue)

Coolest (Capitate - purple)

Positions (Pisiform - pink)

[Normal adult wrist radiograph, shown with and without coloured carpal bones. Courtesy of radiopaedia.]

But did you know that these bones form at different times?

The Capitate ossifies at 1-3 months

The Hamate ossifies at 2-4 months

The Triquetrum ossifies at 2-3 years

The Lunate ossifies at 2-4 years

The Scaphoid, Trapezium and Trapezoid ossify at 4-6 years

And the Pisiform ossifies at 8-12 years

So, I can look at this picture, and tell you that this child is approximately 3 years old, because their Capitate and Hamate have ossified, and their Triquetrum is just visible, starting to ossify below the thumb (circled!)

[Normal wrist radiograph of a paediatric patient, triquetral ossification centre circled. Courtesy of Radiopaedia.]

Your bones continue to form and fuse until you reach about 25! Your olecranon (the bump of your elbow) starts to ossify at 6-11 years, and fuses at 13-16 years! We can look at the base of your fifth metatarsal to age afab folks who are approx. 10 and amab folks who are approx. 12, as this bone fuses in the 2-4 years following these ages! The medial end of the clavicle can be used to assess your age from approximately 18-22, and your facial bones continue to ossify into adulthood! How cool is that?

If you’re over 25, fret not – there’s still plenty of funky stuff happening to your bones. But we’ll get into all of that next time, when we take a look at the function of osteoblasts and osteoclasts and explore all the cool little jobs that your bones perform within your body - it's more than you might think! So, tune in next time for more Bone facts...

And thank you for reading!

[radioactiveradley]

PATHOLOGY OF THE URINARY SYSTEM (aka: STUFF WHAT GOES WRONG WITH YER PISS BEANS)

(AND YER PISS TUBES)

(and the pretty pictures I take of them)

[a warning: this post contains radiographic images and non-graphic description of serious kidney pathologies, including paediatric cancer]

Let's kick off with an old familiar friend! Yeah, I'm talking -

UROLITHIASIS (the humble kidney stone!)

Wanna know something horrific? The biggest kidney stone on record weighed over a kilogram. It was 17 cm across. Just. Imagine. Trying to piss that out…

Urolithiases are formed anywhere among your urinary tracts. They’re commonly found in the kidneys, giving rise to the more common term, renal calculi, or kidney stones.

Urolithiasis occurs when compounds within your urine crystallise. If your urine becomes too acidic, too base, contains too many of these compounds for them to remain in solution, or simply… sits around too long without flowing, it literally petrifies into a solid lump!

Some unlucky souls are just… predisposed to developing them. If you have had a kidney stone in the past, you are far more likely to get another one in the future. There also seems to be a genetic link – so if someone in your immediate family gets kidney stones, you have a higher risk.

Kidney stones typically hang out in the pelvis of your kidney and don’t cause an issue. Until you try to piss them out. Remember our kidney diagram (drawn on a conveniently shaped bean)?

You might notice that the ureters are significantly smaller than the renal pelvis. In other words…

Most renal calculi are made of CALCIUM (oxalate, usually). This is very, very good (for us. Less so for you) because calcium attenuates x-rays – meaning, it glows all pretty and shiny when we take a radiograph!

Here’s a kidney stone on an Abdominal X-Ray!

And a twinkly artefact caused by a kidney stone on Ultrasound!

But the best way to assess urolithiases, is, of course, with CT!

For realsies. We don’t need to inject contrast intravenously, because the kidney stones are (typically) shiny – which cuts down on time and worry, as it means you’re at no risk for having an adverse reaction! So a CT KUB (checking Kidneys, Ureters and Bladder for stones) is basically just a quick tumble in the washing machine (CT scanner), with a lovely clear picture as a result!

Look at these babies!! So sharp!!! So clear!!!!!! So shiny!!!!!!!!!!!! That’s a beautiful matching pair of renal calculi right there – and to make things better, they’re (currently) non-obstructive, so this patient isn’t in suffering The Agonies!

Speaking of The Agonies…

Most kidney stones are passable, albeit with extreme pain.

However, some ain’t going anywhere. Especially staghorn calculi, which, um. One, stags have antlers. Two…

more like a fuckin' MOOSE ANTLER amirite????

But yeah, those buggers aren’t coming out. That’s almost definitely going to require surgery!

Smaller calculi can still cause problems when they become obstructive – i.e., they block the passage of your peepee. They can lead to:

HYDRONEPHROSIS (dilation of the renal pelvis due to retained urine, seen here in the Left kidney [right side of image])

HYDROURETER (dilation of the ureter)

So, what do we do with bothersome calculi? How about some...

EXTRACORPOREAL SHOCKWAVE LITHOTRIPSY (ECSWL, because we love a sexy little acronym here in medworld).

We blast the stone apart with shockwaves, from outside your body! Ultrasound turned up to 11! Unfortunately, it only works on certain densities of stone, and on small stones.

LASER LITHOTRIPSY

(same thing but…. ZIP ZAP LASERZZZZZ]

SURGERY – PERCUTANEOUS NEPHROLITHOTOMY (PCNL).

(I totally haven’t added to this diagram in any way. This is how it works. Trust me.)

LOADS of other stuff can go wrong with The Ol’ Piss Beans

We have:

RENAL CELL CARCINOMA

The most common form of kidney cancer.

For suspected malignancies, we do a CT Urogram that assesses the whole urinary tract. This takes significantly longer than a KUB, but is well worth the results. This is a three-phase scan. We do...

A regular KUB non-contrast scan to check for calculi and to get our baseline Hounsfield Units ('grayness' and densities) for the kidneys. Then we inject contrast in a 'split bolus' - one load immediately, and another roughly 8 minutes in, scanning roughly a minute after the second injection is given. We scan 80 secs after the first contrast bolus is administrered, for the 'nephographic' phase, which enhances the renal cortex & medulla, and makes neoplastic changes and renal masses obvious (see image above). Then we wait 10-ish minutes and scan for the 'excretory' phase, after the contrast has worked its way through your kidneys, to detect 'filling defects' (anything that stops contrast opacification of the ureters) and pathologies related to the urinary collection system.

NEPHROBLASTOMA

This is one of the more common cancers found in kids. Although paediatric cancer is never exactly a happy topic, this cancer is now curable in roughly 90% of cases, thanks to the early removal of kidneys and the possibility of transplants.

Autosomal Dominant (and Recessive) Polycystic Kidney Disease

An inherited renal disease that can cause you to go into End Stage Renal Failure due to the healthy tissue in your kidneys becoming completely overtaken by cysts. As a result, your kidneys can grow more and more, until they practically fill your whole abdomen. 45% of patients will be in ESRF and need dialysis by the age of 60. Thankfully, transplants are an option.

Other commonly encounutered renal pathologies include trauma, which I talked about in my first kidney ramble (linked here!), infections, and more.

I hope you enjoyed this whistle-stop tour of Stuff That Can Go Wrong With The Kidney, And How We Look At Them Gnarly Beans!

....And, um, I spent way too long making this and now need to pee. This is your reminder to go empty that bladder if you need to! Stop those stones!

[radioactiveradley]

What would you consider the hardest imaging modality to work with? Any tips on how to get my eyes adjusted to the different images/radiographs they’re producing? I’m a student struggling with the different modalities and machines and the radiographs are just starting to look like blurry black and white and gray swirls in my eyes. 😵‍💫

Oh goshhhh, best of luck to you!

I'm going to give an annoyingly honest answer to 'which is the hardest imaging modality to work with'. It depends a lot on what you're looking at, and how you're looking at it!

In general, I would say that MRI is the easiest for discerning anatomy. Those are our crisp, clear, pretty images, which differentiate the soft tissues of the body beautifully. Especially when seen in the coronal plane (aka: the view you typically find in anatomy diagrams), it's suuuuper easy to discern different organs.

The only problem is.... it's kinda hard to express that on tumblr, when you can only post one image! MRI and CT produce 2D 'slices' of a 3D image in every plane, meaning that you're supposed to scroll through them to get the whole concept of the anatomy, rather than visualising a single image.

Here is a static normal abdomen MRI image, taken of a pregnant person, courtesy of radiopaedia. But I would enocurage folks to follow the link and scroll through the whole series!

The hardest modality to interpret (and, I would argue, use) in most cases would, in my opinion, be Ultrasound. Ultrasound is a cheap, fast and accessible imaging modality, which is incredibly useful as it can take 'dynamic images' (i.e., video, basically) without incurring a massive radiation dose. The pay-off is.... it's all fuzzy grey blobs.

Guess what this is! Go on, guess! Dingdingding, it's prostate cancer

You can get an awful lot of information out of those grey blobs, but you need a skilled Sonographer with a lot of wrist strength to be performing the exam and interpretating the images. My limp-wristed ass could never.

Ultrasound can be incredibly clear though! Some structures within the body are very difficult to image using MRI or CT, as they are in constant motion - your heart is the classic! We can compile 3D images of these structures by using ECG Gating - we trigger the CT scanner to only take 'pictures' (with radiation) when the heart is in diastole. This results in a gorgeous clear 3D image of the heart! But depending on the stage of diagnosis/suspected pathology, it can honestly be... just a lot quicker, cheaper and easier to whip out the ol' Ultrasound and do some good ol' echocardiography.

Check out this beautiful transthoracic view of the heart, taken using Ultrasound, showing clear differentiation between the four chambers!

Courtesy of Radiopaedia

But what this image can't show you is how this structure is moving, which is the key benefit of Ultrasound. The cardiologist taking this echocardiagram would be watching the motions of the muscle and assessing the function of the valves, not just looking at the static anatomy. Ultrasound might not be the best at creating detailed anatomical images, but it performs very well as a dynamic device, allowing the sonographer to watch various mechanisms at work within the body or, say, find a Deep Vein Thrombus by activating the Doppler and locating the point where the blood has clotted in someone's leg.

As for advice.... my best advice is to develop a three-dimensional model of human anatomy in your head, which you can spin around and rotate as you please to orientate yourself along the different planes used in imaging. Then you can just visualise where you are within your model as you scroll through the images, and figure out the blobby greyness using your knowledge of anatomy!

That sounds WAY easier said than done - and may take serious effort, depending on how good your individual brain is at thinking spatially and reconstructing images in 3D. I'd recommend accessing a resource like Anatomy TV, which lets you basically put human anatomy in the Horse Plinko Machine and twist it about and play with it and prod it from every angle. There are some free versions as well, but I'm afraid I can't vouch for their quality!

Again, best of luck, and keep practicing! It gets easier (and less confusing) I promise you! I am always here if you wanna yell.

[radioactiveradley]

Hello! Any tips on how to identify anatomy/structures/organs on a radiograph? I’m a radtech student and I am taking a radiographic anatomy course and I find it quite difficult to identify what organs are in a radiograph, say for example, radiograph of the abdomen. I have quite a hard time figuring out which part, for example the large intestine, would be the cecum or sigmoid colon. Or if its the whole abdomen radiograph, where are the surrounding organs seem to be located, like kidneys, ureters, stomach, etc. My eyes just can’t seem to focus on each part. If you’ve got any tips, please lmk. Thank you!

That is a truly fabulous question! So, I assume you're talking about bog standard plain film Abdo radiographs (AXR).

I'll do a quick run-down first for those who aren't in the know! We typically take one view of your abdomen: Antero-Posterior Supine (i.e., we shoot x-rays through your front and out your back, while you are lying on your back upon the image receptor).

Techniques vary from trust to trust, but generally...

We ensure your mid-sagittal plane is perpendicular to the image receptor (that you're lying straight, no rotation, shoulders/hips equidistant to the table).

We centre midline between the iliac crests (although I often wind up going an eensy bit lower... This varies on a patient's unique anatomy!)

We collimate to include the xiphoid process superiorly (meaning you hit the diaphragms), the pubic symphsis inferiorly (meaning you get the whole urinary bladder), and the lateral abdominal walls laterally - you may not be able to expand out to skin margins, depending on the size of the patient.

The breathing instructions are:

for an average patient - breathe all the way in. breathe all the way out and hold the exhale (so the diaphragms rise and we can visualise the bowel loops clearly!)

for a very tall patient/patient with a Marfanoid habitus - breathe all the way in and hold the inhale (so the organs are smushed down by the diaphragms and we can fit all yer guts onto one image, meaning we irradiate you far less!)

Typically, we take an AXR to check for (very) Gross Abdominal Pathology - like intestinal obstruction due to volvulus, or toxic megacolon. You can see the organs of the abdomen far more clearly on a CT scan, so anything remotely complex will go there, either immediately or straight after an AXR. We can also see most renal calculi (kidney stones) on AXR, as they tend to be radiopaque, along with many swallowed foreign objects within the digestive system - so those are some more typical radiation justifications!

It's way easier to discern particular organs on an AXR when there is pathology extant. For instance, this is an example of intestinal obstruction. As you can see, the small bowel loops are SUPER OBVIOUSLY dilated.

[case courtesy of radiopaedia]

So, all this is to say.... AXR are more for confirming diagnoses and assessing the level of various pathology, than providing a detailed organ study. However, you can still find your main organ landmarks through some simple tricks!

For instance, I can tell that the small bowel is dilated, rather than the large bowel (colon), because the colon has haustra: bands of muscle that wrap most of the way around its circumferance. The small bowel has plicae circulares - complete circular folds that wrap all of the way around its circumference. As the transverse lines crossing the dilated bowel loops go all the way across, that is a strong suggestion that they are small bowel loops - even if they're dilated to the point where they look like the colon, from the blockage!

But lets look at some non-pathologic anatomy. There are several anatomical landmarks that are just visible on an AXR. Working superior-to-inferior, we have...

Right and left hemidiaphragms

Liver & spleen

Right and left kidneys

Small intestine

Large intestine (ascending / transverse / descending / sigmoid)

Psoas muscles (if these are visible, you have adequate density on your radiograph!)

Urinary bladder

Once you find one of these, you can usually orientate yourself and, roughly, locate the others! I find it easiest to work from the top down. If you've included your full Area of Interest, you should have the R & L hemidiaphragms at the top of the image. Beneath that will be the liver. The right kidney is typically relatively easy to find: it sits lower than the left kidney as it is squashed down by the liver, and its shape, as you can see on the unannotated image below, is relatively easy to discern. The left kidney is harder, but still has a traceable outline, typically. The psoas muscles are sometimes tricky to spot, but you can see them on the (anatomical) right side of the image below if you squint and know what you're looking for. The urinary bladder is either super obvious or... you kinda got to guess, but if you hit the symph (which this radiographer didn't, quite) you know you've definitely got it all on!

AXR is one of the largest radiographs we take. As a result, it's easy to chop off the top or bottom of the image! You'll often see radiographers doing 'cross kidneys' or 'coned bladder' shots on top of a full AXR, just to hit all the anatomy!

[image courtesy of radiopaedia - obligatory note that I too am a humble student, and may be a little off on my anatomical estimations!]

It's important to note that very are MANY 'normal' anatomical variations that cause no pathology. For instance, the person in the above radiograph has a 'Reidel lobe' - a low-hanging liver! Check out the red outline I've drawn around their actual liver - I've included another red line showing where a more 'typical' right lobe of the liver would end.

Colons are also finnicky things with a lot of variation - we've all seen the classic 'ascending/transverse/descending colon' in textbooks, but that's not always the case in actuality. They can be soooo wiggly, and can migrate to surprising places - especially in little old ladies!

As a result (bringing it alllll the way back to your specific question) the caecum is often difficult to locate precisely. It will be SOMEWHERE on the anatomical lower right side of the image, as the sigmoid colon will curve around SOMEWHERE on the anatomical lower left. The sigmoid can be easier to find on an AXR when it's got some faecal matter in situ - it helps you visualise the curve!

Here's my estimate (drawn on the previous normal AXR) for the colon + caecum - I think this person has an exaggerated splenic flexure!

I hope all my rambling was somewhat helpful. My main advice is to learn the 'correct' positions of the anatomy off by heart from textbooks, then use that to muddle your way through all the different examples you can find on radiopaedia and on the internet in general! Print out a load and doodle on them with pens! Squint at AXRs until you start seeing organs everywhere! Start critiquing every AXR you see - how's their collimation, density, and contrast? How many organs can you see? The only way to improve is through practice, and it sounds like you're well on your way!

Best of luck with your studies!