Wednesday, April 30, 2008

Samurai Radiologist Back From the Road

I've been a bit too busy traveling lately to post much. The last 5 days have been spent in Austin, TX and Kansas City, MO, giving 3 talks. Nice to be home again, where I can rest up from the rock-star lifestyle of the academic radiologist.

Mural on exterior of Threadgill's.

I had great fun in Austin catching up on my Texas food groups. I had a definitive chicken-fried steak at Threadgill's and some extra-moist barbecue brisket at Rudy's that were, as my dad would say, just larrupin'. I also got my Tex-Mex receptors well-coated at Maudie's on North Lamar and Vivo. Muy sabrosa!

Besides being a great place to get Texas home-style cooking, Threadgill's also houses a zillion relics from the old Armadillo World Headquarters, the premier music hall in Austin back in the 70's. The Armadillo was to Austin what The Fillmore was to the San Francisco music scene.

Armadillo relief on exterior of Threadgill's.

Lone Star outside of the Texas State History Museum

I also got to visit the wonderful Bob Bullock Texas State History Museum, which has a boatload of Smithsonian-quality exhibits on Texas history.

It also has an IMAX theater, where we saw Dolphins and Whales 3D - an impressive look at quite a few marine mammals in 3D. Watching the finback whale engulf an entire school of fish with one huge gulp was, frankly, awesome, in the original sense of inspiring great awe. I might also add, that if you have not yet seen manatees fart underwater in 3D IMAX, you still have a few more things left to savor in life.

Any nostalgia evoked by wandering through this great museum was further heightened by reading Cormac McCarthy's amazing book, No Country for Old Men, on the plane ride out of Austin.  This book is a great piece of story-telling by any standard.  The fact that just about every scene in the book happened somewhere I grew up magnified its impact considerably.

One can spend years and years away from Texas and come back with attitudes, tastes and politics a whole lot different from the rest of one's tribe.  However, it's comforting to see how many things there still resonate -- sometimes unexpectedly deeply.  I think José Navarro nailed it pretty well in his 1842 quote below.  I love where I live now, but a part of me will always be a piece of Texas.

Tuesday, April 22, 2008

Artificial Muscle Heals Itself, Charges IPod

Professor Qibing Pei and coworkers at UCLA have developed artificial muscle which expands when stimulated with electricity. As it contracts, it generates a small electric current.

This could be exploited in two main ways. If you have plenty of electricity, you can use it to make something move. Conversely, if you have an abundance of movement, you can use it to generate electricity.

The idea of being able to replace damaged skeletal or particularly cardiac muscle with artificial muscle is an exciting one.  However, as far as I know, none of the artificial muscles thus far developed are ready for any kind of clinical trial in humans.  

Conventional muscles are biological motors which use adenosine triphosphate (ATP) for gas. When you hit a muscle's throttle, myosin filaments "walk" along adjacent actin filaments, causing the muscle to contract.

Dr. Pei and his coworkers created their artificial muscle using an electroactive polymer and carbon nanotubules. Their material also demonstrated an ability to "heal" itself ; i.e. seal off microtears to prevent them from spreading to other areas.

I currently spend a lot of time at work looking at magnetic resonance (MR) images of muscles in my patients. I look forward to the day when artificial muscle implants are so common that  I'll have to work hard to distinguish them from the real thing.

(via Slashdot)

Saturday, April 19, 2008

Elective Home Surgery

It's a rare day at work that I don't see dozens of surgical implants, ranging from staples to artificial femurs. Most of these devices were left behind by surgeons to control bleeding, reattach bits of organs, fix a fracture or to completely replace some body part.

However, some of the hardware we see in patients has been self-placed. This usually amounts to some type of body piercing, which is usually of little consequence to most physicians. However, for patients about to undergo an MR scan, we keep a close lookout for metal piercings, since they can occasionally interfere with the scan. This interference is due to the local magnetic field that is induced in even non-ferromagnetic metal objects when placed in the powerful magnetic field of the scanner. In the case of a ferromagnetic piercing, the scanner could exert enough pull on the implant to actually rip it out of the patient's soft tissues.

Knee MR with metal artifact in distal femur.

Occasionally, patients come in with large intrarectal objects, some of which have to be removed surgically. Most of us who routinely read emergency room images have long since become jaded by this type of thing.

It is therefore refreshing to learn of new ways in which people continue to push back the envelope of body modification. One object that I just learned about is the JewelEye, an adornment designed to be implanted within the conjunctiva of the eye. I haven't yet seen a pierced eye locally, but now that I know it exists, I will, so to speak, keep an eye out for one.

My own body mods are pretty much limited to nail clippings and haircuts. Therefore, most of my experience with this is going to remain vicarious. However, I must say that I'm impressed with the energy and dedication that some people devote to self body modification. For example, I once worked with a surgeon who performed his own vasectomy. Alas, most of the people out there doing body mod don't seem to be as well-trained as he was.

Some of the lengths (and shortenings) that people put themselves through and through themselves can be graphically seen on the BMEzine site. The Elective Home Surgery FAQ page hosted on that site contains an impressive amount of content for the would-be auto-surgeon. However, it also contains some equally impressive omissions:
Q. Why do I need to close wounds?

A. (coming soon)

Q. How can I control bleeding?

A. (coming soon)

Q. Things are looking bad. When should I call the ambulance?

A. (coming soon)
When the next bizarre implant case shows up at work, I will console myself with the following: elective home radiology seems to be a lot rarer than home surgery. I'm not sure I really want to know what a dedicated amateur might accomplish with, say, a barium enema kit, a high pressure injector and a portable X-ray machine.

Virtual Strip Searches of Air Travelers

It took zillions of bucks and decades of research, but the U.S. Transportation Security Administration has finally achieved the dream of adolescent males everywhere: a scanner that that lets them view air travelers without their clothes.

Using millimeter wave radio frequency scanning technology, the TSA and others now use this device at some airports. Early tests suggest that 90% of travelers prefer this over the conventional Braille method of secondary screening, i.e. a pat-down search.

The devices currently cost about $US 150,000 -- considerably more than the X-ray goggles sold for years at novelty stores. The radio frequency energy projected by these scanners is said to use only 1/10,000th of the energy involved in a cell phone transmission. Unlike X-rays, this energy is non-ionizing.

The TSA says that to the preserve the privacy of air travelers, these images will only be viewed by a technician located in a remote booth and that the faces will be blurred. However, they don't mention whether these viewing stations will also come furnished with door locks and boxes of tissues.

In theory, the scanners will not be able to store or transmit any of the images they create. In practice, a mere cellphone camera is all it would take to bypass this barrier, so it probably won't be long before these images -- most likely those of celebrities -- start showing up on the Internet.

Will this technology ever be widely used by physicians? I doubt it, except perhaps in physical exams involving patients (or physicians) who are agoraphobic or pathologically shy.

As a parting thought on the matter, here are two short but silly videos on the topic of X-ray glasses:

And this one: X-ray glasses 2

Tuesday, April 15, 2008

Radiologist Monkey Brains Segway Through DC

Oh, for the rock-star lifestyle of the academic radiologist.

It's not all about collating ARRS Attendee Course Evaluation Forms and other tedious paperwork. While collating said forms, one of us recalled hearing about an evening tour through the Capital on Segways, the two-wheeled, self-balancing vehicle. A quick googling of "segway tour Washington DC" led us to all sorts of options, including one that had 5 slots left for yesterday at 6:30 pm.

This was enough to send five torpid academic radiologists scrambling like a SWAT team to get over to Capital Segway in time for the evening tour.

We were given a quick safety briefing, which included all sorts of animated Segway disasters, usually involving a stick figure flying off the device and hitting something. In some scenarios, the figure got run over by his own Segway. Aha, we thought. Even if we don't finish the tour physically intact, we'll have the world's largest series of Segway injuries -- grist for our academic publication mills.


The initial meeting of the cool mechanical mind of the Segway with a fearful monkey brain is usually pretty comical. The monkey brain shrieks, gibbers and flails around, while the Segway calmly corrects for this.

When the wild oscillations finally die down, the next surprise unfolds. As our instructors suggest, merely thinking about moving forward causes the device to roll slowly forward. This is deeply creepy to the monkey brain, even though it knows intellectually that the Segway is merely responding to a subliminal forward shift in weight.

A group of chastened and apprehensive primates then rolls out of the store, survives its first crossing of a downtown D.C. street, and spends 15 minutes in the park across the street getting their sea legs. This is all it takes before we're all zooming around, turning on a dime, and most importantly, stopping at will.

I've spent the past few decades learning a variety of physical skills, including playing the fiddle, telemark skiing, martial arts, juggling and riding a unicycle. I'm therefore quite familiar with the amount of time it can take to cram a complex motor skill into an unwilling cerebellum. It is thence a bit humbling to experience how quickly the Segway bypasses the usual cerebellar learning curve, and compresses months or years of practice down into a few minutes.

Now that we can stop and turn reliably, we then head out for 2 hours of enormous fun. The White House is only about 3 blocks away, and Pennsylvania Ave NW behind it is large, flat, and blocked off from traffic. At this time of day, it is also largely deserted. It is time now for multiple photo ops, and zooming back and forth at speeds up to 12 mph.

After this we spend the next 1.5 hours whizzing around the following sights:
White House / Blair House / Lafayette Square / US Capitol / World War II Memorial / Washington Monument / National Archives / Smithsonian Castle / Air and Space Museum / Museum of the American Indian / National Gallery of Art / FBI Building / Navy Memorial / Newseum / Canadian Embassy / Bureau of Engraving and Printing / Hirshorn Gallery of Modern Art / Willard Intercontinental Hotel / Freedom Plaza / Botanical Gardens
After all of my prior trips to Washington D.C., I am surprised at how deserted the Mall gets after the museums close. Other than a few pedestrians, we largely have the place to ourselves. Since even the most fanatical photo buffs amongst us have left our large cameras safely in our hotels, we are recording this adventure with our iPhones alone.

By 8:30 pm, we are tired and cold, but exhilarated. We roll back to Capital Segway, drop off our machines, and head off to the nearby Les Halles for some hot French onion soup and other yummies.

Tours like this have got to be the world's greatest advertisement for actually buying a Segway. After this adventure, I feel like I finally get the Segway, in a way that a 10 minute demo could never achieve. One groks the Segway the same way one groks the iPhone, Mac Air or Tivo. Intellectual appreciation from afar is one thing, but pales extremely next to a few intensive hours of actual hands-on experience.

The machines currently still cost about $5000, and I've got a lot of other priorities for that much cash. However, for the first time, I am deeply intrigued by this device, and am eager for my next chance to ride one.

Monday, April 14, 2008

American Roentgen Ray Society - 108th Annual Meeting

My attention has been quite focused as of late:  I'm attending the 108th annual meeting of the American Roentgen Ray Society, in Washington, D.C.

108th?  Yes, this organization has been around for a while.  Röntgen himself discovered X-rays in 1895, so the field of radiology quickly evolved all the way to the stage of having stuffy professional meetings in only 5 years -- not bad for a pre-Internet technology.

The ARRS meeting is actually one of my favorite meetings of the year.  The many inevitable opportunities to hear presentations by people poorly trained in public speaking are balanced out by zillions of other, more wonderful things.  In the scientific sessions, I get to see all the new ways my colleagues are using technology to create fascinating images of the body.

I also enjoy the chance to amble through radiology receptions and cocktail parties in a form of Brownian motion, (see the closely-related term: drunkard's walk).  One never knows which cronies one will encounter or what lovely conversations will ensue.

After saying "Yes!" to all sorts of invitations to speak over the past year, I have suddenly had to pay up, to the tune of 9 talks in 3 week long meetings out of the past 4 weeks.

At this meeting, I drew a 7 - 10 split:  2 talks on Saturday and one on Thursday.  Thus, on Monday, I finally find myself with some time free to blog on Monday morning.  If possible, I'll try to liveblog some of the meeting, if only to keep my brain from turning to mush, much as I did during the recent AUR meeting.

Wednesday, April 9, 2008

The Amulets of Seramon

The title of this post sounds like something straight out of Buffy the Vampire Slayer. However, as far as I can tell, no actual vampires are associated with these amulets -- just a 3000 year old royal scribe and middle-class Egyptian mummy by the name of Seramon. A very nice article on this mummy and its amulets was just published on the science section of Apple's website.

Unlike a Buffy episode, Seroman and his wrapping remain undefiled in the Museum of Fine Arts and Archaeology in Besançon, France. Unlike Sunnydale, California, Besançon remains unhaunted by vengeful mummies, and any dread curses triggered by disturbance of the body seem to be on permanent hold. These artifacts were visualized using a CT scanner at the local hospital. The CT data was then reconstructed into high resolution 3D images using imaging software running on various Apple Macintosh computers. The resulting images were apparently detailed enough to read the spell from the Book of the Dead inscribed in hieroglyphs on the undersurface of a 48 x 32 x 18mm stone scarab.

Mummy CT is not a new story. CT has been used since 1979 to image mummies all over the world. However, the quality of the CT images has continued to improve immensely over the years, and the 3D reconstruction algorithms available today provide extremely natural-looking images.

The imaging of this mummy is also noteworthy in that it is
the first time wax amulets have been discovered in situ with non-invasive techniques.
Stone, metal and bone stand out on CT images rather well from other body organs. However, the beeswax used for these amulets has a CT density very similar to that of the mummy's soft tissues.

Our department is periodically asked to image paleoradiology patients such as this, including non-human specimens from mastodons, deep sea angler fish, and ancient musical instruments. When these kinds of cases roll in through our doors, it's a great day to come to work.

Grand Rounds - Vol 4, No. 29

This week's convocation of Grand Rounds is hosted by Dr. Wes, cardiologist, electrophysiologist, and prolific blogger.

Grand Rounds is a weekly roundup that features some of the best medical blogging on the web.

My addition to this episode looks at the question of where in the human body radiologists will stick their, um, noses next: "Radiology Comes Through for Sexual Imaging".

Saturday, April 5, 2008

Science, Y'all!!

Country and western music and pickup trucks are not common vehicles (so to speak) for scientific discourse. The following video by Hard 'n Phirm (Chris Hardwick and Mike Phirman) sort of breaks the heck out of that stereotype.  (caveat: NSFW)

Also, I'm not sure that I've ever heard a pithier formulation of the principle of Occam's Razor.

An additional caveat: after watching this clip, you may, like me, lose additional chunks of your life and cash by crawling through their website, buying their CD, Horses and Grasses, and dumpster-diving through YouTube for more, more more. So far, my favorite CD cuts: Pi, The Carbon Cycle and She Named the Pony Jesus.

(via Pharyngula)

Friday, April 4, 2008

The Face of Leonardo Da Vinci

Here is a very short and very intriguing video clip from the always excellent TED conference. Illustrator Siegfried Woldhek has drawn over 1100 faces in his career, giving him some expertise in the area of facial features.

(via Neil Gaiman's Journal)

Daily Caffeine 'Protects Brain'

BBC News: Daily Caffeine ‘Protects Brain’: this article describes results just out in the Journal of Neuroinflammation.
The drink has already been linked to a lower risk of Alzheimer's Disease, and a study by a US team for the Journal of Neuroinflammation may explain why.
It's hard to improve on John Gruber's précis of this story:
From the department of things I link to because I really hope they’re true.
In fact, I'm putting my money where my mouth is by sipping some expensive caffeine even now. I don't know if my brain is being protected from cholesterol, but it certainly feels less fuzzy than it did 30 minutes ago.

Two quotes from one of the study authors:
Caffeine is a safe and readily available drug and its ability to stabilise the blood brain barrier means it could have an important part to play in therapies against neurological disorders.
Caffeine appears to block several of the disruptive effects of cholesterol that make the blood-brain barrier leaky.
Pardon me while I run out and buy some Starbucks stock...

Wednesday, April 2, 2008

Home AED Use for Precocious Geezers

As we precocious geezers contemplate the various ways we will someday exit this globe, one means looms large: cardiac death. Fortunately, this specter of heart disease can be exorcised somewhat by appropriate technology, such as coronary stents, cardiac pacemakers, and automated external defibrillators (AED). All of these devices have done a great deal to prevent some cardiac deaths.

I'm currently reasonably healthy, but remain a bit sensitized to this issue due to a friend having a cardiac arrest before my eyes at a dance last year. As I posted earlier this year, prompt CPR and a nearby AED got my friend's heart started again. My spouse and I now own a personal AED unit, and take it with us to dances and other events. We also keep it readily accessible at home.

Therefore, I read this article from the current issue of the New England Journal of Medicine with particular interest. It's titled Home Use of Automated External Defibrillators for Sudden Cardiac Arrest, and presents the findings from a randomized study of home AED use in 7,001 subjects with prior anterior-wall myocardial infarction (a specific variety of heart attack). The gist of the article:
For survivors of anterior-wall myocardial infarction who were not candidates for implantation of a cardioverter–defibrillator, access to a home AED did not significantly improve overall survival, as compared with reliance on conventional resuscitation methods.
These results are mildly disappointing if you own your own AED, as we do. They are even more disappointing if you are Philips corporation, who currently sells the only AED on the market that is FDA-approved for home use (and may have been hoping to use the results of this study to sell a zillion more home AED's).

The demographics of this study population don't extrapolate well to our house, since none of us have any prior history of cardiac disease. However, neither did the friend we helped to resuscitate last year. Furthermore, I take heart, so to speak, in the following details from the study:
AEDs were used in 32 patients. Of these patients, 14 received an appropriate shock, and 4 survived to hospital discharge.
A simple analysis of these numbers: 4/14 (29%) of those who were shocked were long-term survivors. If there had been no AED available, this survival rate would have been much lower -- like zero. We won't be putting our AED on eBay anytime soon.

Other points of interest from this study: 83% of the subjects were men, and 88% of the rescuers were married to the subject.

Putting all of these factoids together, here's the Secret Master Plan™ I would suggest for surviving a home cardiac event:
  1. keep an AED around the house
  2. have a significant other
  3. be really, really nice to your S.O.
  4. make sure they know CPR
  5. make sure they know how to use your AED

Tuesday, April 1, 2008

Something Radiologists Could Learn from Netflix

We all make mistakes. The way we handle it after that makes all the difference. The Remiel blog nails this concept in the quote below, and goes on to recount the very graceful path Netflix took to making it right after a shipping error.
When I used to wait tables, one thing I learned early on was that a small mistake by me or the kitchen was actually an opportunity for me to make more money. Customers were routinely far more impressed with a well-handled mistake (which they actively noticed) than with trouble-free service (which they took for granted).
I'll try to keep this in mind the next time I screw up with one of my radiology customers.

(Via Daring Fireball.)

New Compression-Only Guidelines for Bystander CPR

This just in:  the American Heart Association has just published new CPR guidelines for bystander CPR in the journal Circulation. The bottom line:
People who witness an adult collapse with apparent cardiac arrest should be urged to provide chest compressions without ventilations.
In my post on this topic last month, I made the following wild prediction:
If a randomized controlled trial corroborates the findings in this study, I expect to see a lot of changes in official CPR protocols.
Apparently, it wasn't so wild after all.  The AHA seems to feel it's time to update the guidelines right now, and I think they're right. Even if this new compression-only technique works no better than standard CPR, this simplified protocol may increase the likelihood that a bystander will actually administer CPR. As the authors quote:
...provision of chest compression without mouth-to-mouth ventilation is far better than not attempting resuscitation at all.

Radiology Comes Through for Sexual Imaging

There's a lot we don't know about the human body.

How can this be, after radiologists and other physicians have spent the past 113 years scanning every known body part?

Simple answer -- most medical imaging is done on sick people. In general, this is not a bad idea, since imaging procedures can occasionally have significant side effects.

Unfortunately, this also means that a lot of normal body functions remain under- or even un-imaged. This includes images of what actually goes on during sexual intercourse.

A lot of the ins and outs of the old in-and-out have been elucidated by researchers such as Alfred Kinsey, William Masters, Virginia Johnson, and Shere Hite. However, we still have a lot to learn.

Enter the field of sexual imaging -- a field that seems to be pursued avidly by scientists and laypersons alike. In the past decade, ultrasound, magnetic resonance imaging (MRI) and even X-rays have been used to go where no eyeball has gone before.

Sexual imaging has some obvious difficulties. For starters, both researchers and their subjects have to overcome some of the personal and societal baggage that is still associated with sex. As one researcher put it:
It took years, a lobby, undesired publicity, and a godsend (two tablets of sildenafil (aka Viagra) 25 mg) to obtain our images.
Even when you've got someone willing to do it in front of an audience and someone else willing to watch, access to the really interesting details remains challenging. Despite all manner of cunning lenses, mirrors and probes, many of the places where genitalia meet other genitalia (and other orifices) have, until recently, remained dark, private and inaccessible.


In what one might truly consider "lay" research, Belgian artist Wim Delvoye asked several friends to paint parts of their bodies with barium, and then X-rayed them having sex in a medical clinic, presumably after hours. Delvoye has turned several of these images into stained-glass windows.

Some of the these radiographs can be startlingly graphic, but shed a bit of light on some of the messy details of what actually happens during sex. The downside of this adventure is the ionizing radiation exposure to each of the gonads, thyroid glands and eyeballs in these images. Eek.


In 2006, Deng et al published Real-time three-dimensional ultrasound visualization of erection and artificial coitus. No ionizing radiation to worry about here. However, the authors state:
For the first volunteer scanned with the water bath alone, the penis failed to erect within 30 min.
Imagine that -- someone couldn't get it up while surrounded by a group of researchers holding ultrasonic probes. To me, this sounds a lot like an alien abduction scene -- except without the aliens and without the abduction.

The other four volunteers in this study were given an artificial vagina made of gel, which apparently
...successfully initiated and maintained the erection and allowed artificial intercourse.
From what I can tell, this particular artificial unit is still Not Found in Stores.


Like ultrasound, MRI does not use ionizing radiation. Unlike ultrasound, MRI allows one to avoid the whole surrounded-by-probes-and-eyeballs scene, and sexual acts can be imaged in the relative privacy of the MRI scanner.

MRI has been used to study blood flow and size of female genital and pelvic organs during sexual arousal. Not surprisingly, blood flow increases in the labia minora, clitoris and in the vagina.

MRI has also been used by Pretorius et al
... to non-invasively monitor the intravaginal distribution of an applied intravaginal gel, we performed high-resolution magnetic resonance imaging (MRI) of the female pelvis before, during and after both real and simulated sexual intercourse.
The good news: intercourse did a really great job of spreading the gel. The bad news (for men, at least): a plastic phallus worked just as well as a real one.

When reading through these research papers, it is quickly apparent that some of these studies were a whole lot more fun than others.

My favorite is the pioneering work by Schultz et al, published in 1999. To my knowledge, this is the first reported use of MRI to image actual coitus while it was in progress. Their subjects performed missionary work that even an atheist could support.

This study sounds like a lot of fun, but was probably more grueling than one might think. First, many patients find the bore of an MR scanner to be close quarters to the point of claustrophobia -- even without sharing the space with a naked partner. My hat is off to anyone who can crawl into an already-occupied MR scanner, much less successfully "dock" with their partner. Second, only one couple was able to successfully perform coitus without the use of Viagra. The authors suggest that the success of this non-Viagra couple may be because amateur street acrobats they are trained and used to performing under stress.
Unlike the men, all of the women had a complete sexual response. However, any anxiety the men in the study felt due to their need for Viagra may have been somewhat mitigated by the study's finding that
Scanning of the position of the human genitals during coitus gives a convincing impression of the enormous size of the average penis in erection.
Balm indeed for a troubled male ego.

One surprising discovery was the shape the penis assumes during coitus. Even Leonardo da Vinci got this wrong. He, along with everyone else, assumed that a phallus in flagrante delicto is pretty much the same shape as one that is just plain old flagrante out in the open. In fact, a penis bends into the shape of a boomerang during penetration.

Another surprise -- in contrast to the bimanual estimates of uterine size made over 30 years before by Masters and Johnson, this study did not show any increase in size of the uterus during sexual arousal.

Replication of results is the very heart of the scientific method. This is doubly true when one is screwing for science. You will therefore be happy to know that this valuable work has been carefully extended by Faix et al to other pages of the Kama Sutra. They carefully imaged couples not only in missionary position, but also in reversed missionary position and rear entry position. Their findings may be troubling to some men -- despite some persistent fantasies, the penis does not actually extend any further cephalad than the north end of the vagina.

Note: Despite the date of this post, the papers quoted here are all actual research papers from the actual medical literature.