MiWord of the Day Is… Magnet!

Who hasn’t thought of having Magneto’s powers? No? Maybe you should watch this Magneto trailer for a refresher. 


Ok, now that we all want to be Magneto (secretly at least) what is it that is so appealing with having the power of magnetism? Bill Nye the Science Guy explains it very well in this clip. Have a gander.


In a nutshell, magnetism is a physical phenomena that consists of a field of energy created by “magnets” that attracts or repels other objects. Magnets come in two major flavors: permanent magnets made of materials (such as iron) and electromagnets – the strongest and most widely used in medical imaging. 


Interestingly, it is the sum of the magnetic fields of individual electrons that is responsible for all the fun (see quantum mechanics). In the case of electromagnetism the electric current in a wire produces a magnetic field in the same direction of the current. In the case of a permanent magnet it is the magnetic fields of the naturally occurring electrically charged particles of the atoms that make up the material (iron for example) that are responsible. However, for there to exist a force strong enough to attract or repel another object all of its magnetic ions must have their magnetic fields aligned and contributing to the net magnetization. This is how you can magnetize a needle when stroking it in a uniform directional way with a permanent magnet.





Magnetism is to MRI what radiation is to X-rays. The strength of magnets is measured in gauss and Tesla units. There are 10,000 gauss to a Tesla and the earth’s magnetic field is one half of a gauss. Today most clinical MRIs use superconducting magnets whose strength range up to 4 Tesla! Experimental MRIs can run up to 10 Tesla. Now that is more Magneto’s speed.


The powerful magnets allow for better spacial resolution allowing for better sensitivity of the image. However, all this magnetic strength comes at a cost: the production of chemical shift artifacts – ghosts of things that are not really there. This is why we have radiologists to make sense of it all.


OK. Now you are asking what the heck. Magneto in the X-Men movie was able to rip out the iron from a human so why doesn’t an MRI? Great question. Iron found in the human body is mostly found as ferritin (a type of iron oxide) and is NOT magnetic. The iron in hemoglobin is also NOT magnetic. Bummer. So how does Magneto do it? Well either the movie is not scientifically correct (now that would be a shocker) or possibly he could be drawing on magnetite (another iron oxide) that is magnetic and has been found in trace amounts in the blood and brain. It is so little though that it does not cause any concern for MRI. Oh well, so much for Magneto…

Now for the fun part (see the rules here), using magnet in a sentence by the end of the day:

Serious: Hey Bob, did you know that early MRI machines used permanent magnets?

Less serious: Went for my MRI today. Told them I was worried the MRI would rip all the iron out of my blood like in X-Men. They didn’t even know who Magneto was. Whaaaat?!!

OK, listen to Magnetic by Traphik to decompress and I’ll see you in the blogosphere…

Pascal Tyrrell










MiWord of the Day Is… Xeroradiography!

Who hasn’t done some creative photocopying at some point in their lives? I certainly do NOT condone this type of activity (very naughty) but would you believe me if I were to tell you that for a long while mammography made use of photocopy technology? Yes, I realize this sounds a little funny. Let me explain.


In the 1970s medicine made the association between heavy exposure to radiation for TB and thyroid treatments and the appearance of breast cancer three decades later. A reevaluation of the effects of radiation ensued and a call for ways to minimize exposure to ionizing radiation was made to the industry.


One of the first to answer that call was the radiologist John Wolfe from Detroit Receiving Hospital who in 1966 reported on the advantages of coupling photocopy technology with mammography. Xerox corporation jumped on the idea and developed a commercial unit in 1971 and “xeroradiography” was born! Basically, film from traditional x-ray imaging (yes back then they still used film!) was replaced with a selenium coated aluminum plate that was prepared for the exposure by being electrically charged. The result was that only a short burst of radiation (shorter exposure time means lower dose of radiation) was required to produce a very high quality image.






These xerox mammograms dominated the industry for over 20 years until new technology was developed more recently that provided even finer images with even less radiation. Cool.




Now for the fun part (see the rules here), using Xeroradiography in a sentence by the end of the day:


Serious: Hey Bob, did you know that mammograms produced using xeroradiography were blue? 


Less serious: My friend Jane was scheduled for a mammography. Having heard of xeroradiography reading the MiVIP blog she decided to DIY at her office. Problem was the print kept coming out black and white instead of blue from the Xerox machine…




OK, watch the Copy Cat trailer to decompress (or not?!!!) and I’ll see you in the blogosphere…




Pascal Tyrrell

MiWord of the Day Is… PET scan!

 

Peanuts. What a great story. The most popular and influential comic strip in history. Snoopy was my first stuffed animal growing up. He still lives with my parents. So what is a PET scan anyway? I don’t recall ever seeing the picture above in any of the Peanuts cartoon strips.





Positron emission tomography (PET) is somewhat of a special medical imaging modality in that it brings together two different technologies from different times. Let me explain. Back in the early 1930s, George Hevesy was a young Hungarian physicist who developed biologically safe and useful radioactive tracers that could be ingested or incorporated into the body in some way.  Physicians would then manually locate where these radioactive tracers had gone in the body by using a Geiger counter at first and then later using special cameras (Kuhl‘s photoscan) to produce a crude emission image. 



So, how do we get cool pictures like these ones?  Well we would have to wait another 25 years after the development of radioactive tracers by Hevesy for the start of construction of instruments able to not only detect these radioactive sources in the body but to produce tomographic pictures.


It won’t be until the mid 1970s that PET – as we know it today – would be born. Essentially, a patient receives a emissions scan (PET) and a CT (we talked about that here) or MRI (we talked about that here) scan at the same time. The two scans are then merged together thanks to highly specialized computers (see the pictures in the middle frames). Voila! PET. 



PET is both a medical and research tool. Most often used in clinical oncology (medical imaging of tumors and the search for metastases), it is also important in clinical diagnosis of certain diffuse brain diseases such Alzheimer’s disease and other types of dementia.


Relax your brain a little listening to Radioactive by Imagine Dragons and don’t forget the fun part (see the rules here), using PET scan in a sentence by the end of the day:

Serious: Hey Bob, did you know that much of the success of the PET scan is due to the development of the radiopharmaceutical FDG (deoxyglucose) that lead the way to the characterization of Parkinson’s and Huntington’s disease?

Less serious: I can’t believe they developed yet another PET scan. Wasn’t the CAT scan enough?

See you in the blogosphere,

Pascal Tyrrell








 

MiWord of the Day Is… Mesopotamia!

You are thinking about pursuing studies in medicine. You have enrolled in all the necessary courses at school to qualify you for the grueling application process and you are actively looking for volunteer opportunities. So why the need to be active in your community?


Today, I want to talk a little about the history of medicine. Around 3000 BC (and no I was not alive then if you are wondering) the middle east was a hotbed for civilizations who were in transition from being mainly nomadic to more settled. This “land between the rivers” – Mesopotamia – was ruled by many successive great kingdoms including the Akkadian, Babylonian, and Assyrian empires. Thanks to many archaeological and written remains we have discovered that healing practices indeed existed and were established during these times.


Mesopotamian medicine was predominantly religious and was delivered by a team of healers: the seers who would diagnose based on divination, the exorcists who would expel demons, and finally the physician priests who actually treated the sick mostly with charms, drugs, and some surgical procedures.  OK, so this intensely codified approach (which meant very little opportunity for discussion)  to healing that dominated the Mesopotamian kingdoms would not be able to adapt or improve much over time and would ultimately not contribute much to the Greek rational medicine that would come a later and evolve into today’s medicine. 


So why is it important? For two reasons:


Firstly, by understanding the history of medicine you will better appreciate the importance of your role as a physician in your community – regardless if you are a primary care physician on the front line or a radiologist who works in the back ground. What is important is to feel connected and part of your community.


Secondly, it is interesting to see that though Mesopotamian medicine recognized very early on that factors like cold, alcohol, and unhygienic conditions affected health, they were enable to advance and evolve their medicine as Ancient Greece did through ongoing experimentation and discussion. Moral of the story? Medical research rocks!




Do you remember the Babylon 5 series? It came many, many, many years later! Have a peek to decompress and…


… I’ll see you in the blogosphere.




Pascal Tyrrell



MiWord of the Day Is… Haptoglobin!

 

Just got back from the RSNA! Wow what a big conference – 56,000 people this year. McCormick place in Chicago, Illinois (where the conference is held) feels like an airport it is so big. 


Love Chicago. Great city. 


Of course, I had the pleasure of attending a bunch of great presentations and today I will introduce you to one of them. Tina Binesh Marvasti (say that 7 times fast!) presented on the topic of Haptoglobin. No, not Hobgoblin (not sure who that is? See here) or his infamous green predecessor (see here). 


So, what is Haptoglobin you ask? It is a serum protein that binds free hemoglobin – resulting from the breakdown of red blood cells – and functions to prevent loss of iron (contained in the heme group) through the kidneys and to protect tissues from the highly reactive heme groups. Essentially a housekeeping protein that helps to recycle hemoglobin as part of the red blood cell life cycle. Now what if your ability to clean-up free hemoglobin was impaired? Well, quite simply you would be putting at risk those sensitive tissues that come into contact with free hemoglobin. 




One important example of this is vessel walls affected by atheroma (AKA plaque). Sometimes these atheroma can bleed (called intraplaque hemorrhage or IPH) which worsens the whole situation. Typically, your body responds by sending the clean-up crew including the Hobgoblin (or haptoglobin, I always get these two confused). 











When people have the recessive genotype (Hp 2-2) of the Hp gene they produce less haptoglobin and therefore are at increased risk of damage from free hemoglobin (or more specifically the heme groups).



Tina and friends hypothesized the following: 













And she found that having the recessive Hp2-2 genotype was associated with a higher prevalence of IPH in a group of  80 patients (average age of 73 yrs). She also found that the IPH volume of Hp2-2 patients worsened over time.








So what is the take home? The Haptoglobin genotype is associated with IPH which is a biomarker of high risk vascular disease and could identify populations at higher risk of developing cardiovascular events.

 

Now for the fun part (see the rules here), using Haptoglobin in a sentence by the end of the day:

Serious: Hey Bob, did you know that a recessive haptoglobin genetype may contribute to an increased risk of cerebrovascular disease?

Less serious: My GP suggested that based on my recessive hobgoblin genotype I should consider a healthier lifestyle. Funny, I always figured Doc Ock to be the one to watch for…

OK, watch the Spider-man 2 trailer to decompress and I’ll see you in the blogosphere…

 
 
 
Pascal Tyrrell

MiWord of the Day Is… CAT scan!

A what scan? I am actually a cat guy myself. Not to say I don’t love dogs but if I had to make a choice…


I just finished reading a fantastic book by David Dosa entitled “Making Rounds With Oscar”. The premise of the book is a story about an extraordinary cat but the subject matter is very serious –  dementia and end-of-life care in the elderly. Have a gander.


So what the heck is a cat scan and what does it have to do with medical imaging? 


CT scans – also referred to as computerized axial tomography (CAT) – are special X-ray tests that produce cross-sectional images of the body using X-rays and a computer. CT was developed independently by a British engineer named Sir Godfrey Hounsfield and Dr. Alan Cormack and were jointly awarded the Nobel Prize in 1979. Yes, more Nobel prize winners…






In a nutshell, x-ray computed tomography:


– uses data from several X-ray images of structures inside the body and converts them into 3D pictures – especially useful for soft tissues.


– emits a series of narrow beams through the human body, producing more detail than standard single beam X-rays.


– is able to distinguish tissues inside a solid organ. A CT scan is able to illustrate organ tear and organ injury quickly and so is often used for accident victims.


– is analyzed by radiologists.


Unfortunately, unlike MRI scans, a CT scan uses X-rays and therefore are a source of ionizing radiation.





Now for the fun part (see the rules here), using CAT Scan in a sentence by the end of the day:

Serious: Hey Bob, did you know that the recorded image of a CAT Scan is called a tomogram? 

Less serious: My GP suggested that howling at the moon at night is not normal behavior and he wants to send me for a CAT scan. What? No way, I’m allergic to cats…

OK, listen to Cat Stevens to decompress and I’ll see you in the blogosphere…


 
Pascal Tyrrell

MiWord of the day is… Atom!

MiWord, a post on Sunday?!!! Well, I have been very busy lately and fell behind on my blog so I am now playing a little catch-up…


I was waiting in Logan airport for my flight back from a presentation in Boston – what unbelievably crazy traffic in that city – and I was texting my kids with my laptop open and my tablet next to me on the seat when I thought: I feel a little like Jimmy Neutron! I enjoyed watching that show with my kids. Lots of fun. Anyway, that idea of crazy science and the internal structure of the atom as displayed on Jimmy’s t-shirt may be the premise for a great kids show but it also led to the development of MRIWhat?!!! You say. 


MRI is an imaging technique. Maybe so, but it is particular in that it does not use any classic photographic equipment (film or lenses) or use x-rays as Roentgen did. It simply numerically measures how hydrogen nuclei absorb and release energy in response to particular frequencies. Need a refresher on the structure of an atom? See this post.


Don’t get it? OK, how about you think of this process as a crazy huge tuning fork. If you were to flick a tuning fork of a certain frequency (pitch) other tuning forks of the same frequency close by will pick up energy from the humming tuning fork and emit a sound in turn. Cool.


The nucleus of an atom can absorb energy and then relax by emitting energy in a similar way. Different atoms (or the same atom in different environments) will have different relaxation rates allowing for the identification of the composition of molecules. Ya, maybe a little complicated.





MRI measures how hydrogen nuclei absorb and release energy. Dependent on the location and the environment of the hydrogen atoms the MRI process is able to provide knowledge about the placement of hydrogen atoms in the body and in turn knowledge about the anatomy.





Now for the fun part (see the rules here), using Atom in a sentence by the end of the day:

Serious: Hey Bob, did you know that the atom is the smallest unit that defines the chemical elements and their isotopes?

Less serious: I thought that splitting atoms would produce a large explosion but when I tried using my mom’s perfume “atomizer” it just produced a fine spray and nice smell…




Ok that was a little intense for a Sunday. Watch and listen to Symphony of Science (very cool BBC production) to decompress and I’ll see you in the blogosphere…




Pascal Tyrrell

MiWord of the Day Is… Cinemaradiology!

Yes, it is Halloween today and my kids could barely contain themselves getting ready for school. I suspect today will not be very productive as they count down the minutes before heading out to terrorize my neighbors.


Anyway, how about this for a scary thought: cinemaradiology! In the late 1800’s John MacIntyre at the Gasgow Royal Infirmary experimented with producing X-ray motion pictures. What!!!? He tried exposing film by passing it between the screen of the fluoroscope and the x-ray tube and by simply filming the fluoroscopic screen. This latter method was very difficult because, as all of you budding radiologists know, the images viewed on the fluoroscope screen were dim and of poor resolution at the time.


For years researchers worked on perfecting cinemaradiology. However, during those early years of discovery they lost interest when they realized that sharper images were possible when BOTH patients and investigators were exposed together AND that excessive radiation was a bad thing – duh! 


It would only be many many years later that fluoroscope screen technology would be improved to allow for brighter and higher resolution images (and without frying the patient and everyone around!). 

Fluoroscopy is a study of moving body structures – similar to an x-ray “movie.”  A continuous x-ray beam is passed through the body part being examined, and is transmitted to a TV-like monitor so that the body part and its motion can be seen in detail. As an imaging tool, Fluoroscopy is used in many types of examinations and procedures.

To my knowledge, no actors from the cinemaradiology era ever became successful stars in Hollywood…


No need to use the MiWord of the day in a sentence today (see rules here) as I realize you are busy getting ready for Halloween and need a break!


Decompress listening to the classic song Thriller by the King of Pop Michael Jackson and I’ll see you in the blogosphere…






Pascal Tyrrell

 

MiWord of the Day Is… Cuckoo!

One of my favorite more serious films is One Flew Over the Cuckoo’s Nest. What does Jack Nicholson’s portrayal of a bad guy hoping for easy served time in a mental institution have to do with medical imaging? Well it all starts with the lobotomy. Not to spoil the story, suffice it to say that the movie broaches the topic of lobotomies and how ridiculous they were. Lobotomy was a form of neurosurgery that involved damaging the prefrontal cortex in order to “calm” certain mentally ill patients. Needless to say the procedure was controversial from the beginning (1935 to the early 1970’s) but the author of the discovery, Egas Moniz, was awarded the Nobel Prize in 1949. Maybe not the most sound of decisions by the committee. However, for the time, it was considered progress in a very challenging area of medicine – mental illness. 


OK, medical imaging? Well as it turns out Moniz (do not confuse with St-Moriz, ahhh skiing…) is also known for developing cerebral angiography – a technique allowing the visualization of blood vessels in and around the brain. 



Moniz was interested in finding a non-toxic substance that would be eliminated from the body, but would not be diluted by the flow of blood before the x-ray could be taken. Another requirement is that the substance could not cause an emboli or clot as this would be a bad thing. Moniz played with salts of iodine and bromine and settled on iodine because of its greater radiographic density. And voila, birth of iodinated radiocontrast agents still in use today. Cool.




Supposedly it took him 9 patients to perfect his angiogram technique. Don’t ask about the first 8…

Moral of the story is: lobotomy bad and cerebral angiography good.



Now for the fun part (see the rules here), using Cuckoo in a sentence by the end of the day:

 
Serious: Hey Bob, when I was visiting my aunt in Australia I spied a little bronze cuckoo in her backyard! This could be my “big year“…


Less serious: Someone won a Nobel Prize for developing the lobotomy? Are you cuckoo?
 
 
Listen to Los Lobos (not short for lobotomy but “the wolves” in Spanish) singing La Bamba to decompress and…
 
… I’ll see you in the blogosphere,
 
 
Pascal Tyrrell

MiWord of the Day Is… Fluoroscope!

It is hard to believe that the fluoroscope (essentially an x-ray machine used to produce real-time moving images viewed on a screen of the internal structures of a patient) was used to “help” better fit shoes to your feet! From the 1920 to about 1970 you were able to irradiate your feet with x-rays in order to see if you had enough “wiggle-room” in your new shoes! Crazy. 
 
So, the whole concept of Fluroscopy dates back to you know who, Wilhelm Röntgen. We chatted about him here in our blog. He is also responsible for discovering the interesting phenomenon of barium salts fluorescing when exposed to x-rays (see here in our blog). 
 
Basic function of a fluoroscope
Soon after Rontgen’s discovery was announced, Thomas Edison (the light bulb guy) decided he could improve on this whole x-ray thing as these rays were produced by a “glass tube apparatus” – something he knew a lot about. After setting his team to work – he had a team as he was a very successful man in those days following his 1879 patent of the light bulb – they soon discovered the risks of working with x-rays. Edison decided to remove himself (literally!) from x-ray research. But before he did he developed one of the first (and arguably the most advanced in it’s time ) fluoroscopes along with a full line of x-ray kits. He also coined the term “Fluoroscope”. Interesting man…
Fluoroscopes have come a long way over the years and are still used today in areas such as orthopedic surgery, gastrointestinal investigations, and angiography but, of course, the dose of x-rays a patient receives is minimized and closely monitored. Have a look at this machine from Siemen’s. “Beam me up Scotty!”. 
So how did all of these machines suddenly flood the shoe retail industry? Good question. As it happens, following the development of the high vacuum, hot cathode, tungsten-target x-ray tube by William Coolidge in 1913 the interest for a portable and reliable machine increased dramatically with the advent of the First World War. The successful deployment of numerous machines during the war to aid army physicians spurred the manufacturing industry to mass produce them. After the war, the impact the fluoroscope had on army medicine flowed into community practice. 
 
Due to the enormous supply of portable x-ray machines at the time following the end of the war, Dr Jacob Lowe introduced the idea of using a modified portable x-ray machine in the shoe retail industry. Voila, fried feet fricassee for the next 50 years!

Now If were to be interested in using a fluoroscope to look at my feet I may be inclined to use a suit like this gentleman below is sporting…

WW I x-ray protection suit

Now for the fun part, using Fluoroscope in a sentence by the end of the day:


Serious: Bob, did you know that the foot-o-scope was a modified fluoroscope used to view ones feet when fitting new shoes which delivered on average 13 Roentgens for every 20 second exposure?


Less serious: I heard grampa grumbling he can never find shoes that fit right anymore since they banned fluoroscopes in shoe stores. What is a fluoroscope mommy?




Listen to High Heels to decompress and I’ll see you in the blogosphere.




Pascal Tyrrell