Monday, March 31, 2008

My Body Could Feed 16 Cannibals

While searching for something completely different, I ran across this site, which gives one yet another reason to eat less and exercise more.

As I've blogged before, radiology is a pretty darned sedentary job. The "exercise more" part is definitely going to have to come outside of work.

It would be really nice to starve at least one of those sixteen cannibals by summertime...

Linux Developer Gets Laid -- Can Radiologists be Far Behind?

Going into radiology is not widely considered to be an effective mating strategy. Anyone who thinks working around magnetic resonance imaging also makes you a magnet for babes or hunks is soon sadly disabused. However, this story gives some hope to geeks of all ilk.

The secret ninja technique used by this Linux dude is something that radiologists might also consider (Boards-ready senior residents, I'm talking to you). It would seem that a major step forward in getting laid is getting a life (even a small one).

Hmmm, it's worth a try...

(Via Fake Steve Jobs.)

Thursday, March 27, 2008

Knee MR Fellowship, According to Google

Last month, I posted about the travails of searching for medical images on the web, in Desperately Seeking Supraspinatus.

A few nights ago, I searched Google Images for the following phrase: "knee mr". At that particular time, the very topmost hit was the image below:

According to the subtitle of the image, I got exactly what I asked for: "knee" followed by "mr".

Somehow this wasn't quite what I had in mind for my lecture. :-)

Tuesday, March 25, 2008

Live-Blogging the AUR Meeting

Tuesday, March 25

As I mentioned in an earlier post, I'm spending this week in Seattle at the annual meeting of the Association of University Radiologists. After the first few sessions, my brain is beginning to disintegrate.

To remain conscious through some of the sessions, I thought I would live-blog the meeting via my iPhone in the comment section of this post.

As an exercise, I will try to keep the bulk of the posts to exactly 6 words, as in my earlier post on Six-Word Memoirs.

Six-Word Memoirs

The Seattle Post-Intelligencer recently challenged its readers to write their life story in just six words. The results of this challenge are now online.

My favorite is by Cheryl Stumbo,
one of five women wounded in a July 2006 shooting at the Jewish Federation of Greater Seattle -- a shooting that claimed the life of annual-campaign director Pamela Waechter.
Her memoir:
Bullies keep trying; I thrive anyway.

I also liked Doug Bradeen's
Raised daughters. Still don't understand women.

John Imhoff's
Now playing. Held over. Ends soon.

and Anne Whitacre's
Great jobs; good dogs; mediocre men.

The masthead for this blog appears to have answered this challenge on its own, while my back was turned:
Shedding invisible light on medical imaging.

Six-word comments would be welcome.

Monday, March 24, 2008

To "Glow" Where No One Has Gone Before

I didn't make up the title of this post -- it's from an article on the Medscape site called: To "Glow" Where No One Has Gone Before: The Risk for Radiation to Space Exploration.

If you happen to be a physician, you can actually earn 0.75 CME credits after reading this article. Interestingly enough, the legal disclaimer for physicians includes the following morsel of text:
These materials may discuss therapeutic products that have not been approved by the US Food and Drug Administration and off-label uses of approved products.
Hmmm.... medical care in space? Off label? You think?


Despite this generic, mealy-mouthed caveat, the article itself is well-written and informative. It gives a very nice discussion of the issues you may face on your next trip to the moon.

For one thing, I hadn't been aware of the "great solar storm" of August 4, 1972. Fortunately, this storm occurred between the last 2 Apollo lunar landing missions. If it had hit while we had folks on the moon, they would have received a rather large, and possibly lethal dose of radiation. Yikes!

Of course, radiation from space affects folks who fly much lower than astronauts. At the altitudes used by commercial flights, one receives radiation from space that would normally be absorbed by the atmosphere. For example, 3 round-trip flights from LA to NY roughly equal the dose from one medical chest X-ray. I've know for years about this increased dose from high altitude flight, but had not given much thought to the further increase in exposure at the earth's poles.
Solar particle events (SPEs) are primarily responsible for generating high-energy proton emissions from the sun during solar storms.

The earth's magnetosphere tends to protect most objects in low earth orbits, but this effect has its minimum at the poles. I had no idea that
...airlines routinely work around the impact of SPEs (solar particle events) on polar flight trajectories...
Eek. A polar flight trajectory would describe any number of my flights to Europe. Who knew that the airlines are already factoring in space weather along with the much more prosaic terrestrial weather we expect!

Another interesting quote from this article:
Is there a risk to the central nervous system and brain from exposure to heavy ions at the level that would occur during long missions into deep space? In other words, to quote Derek I. Lowenstein of Brookhaven National Laboratory, "If every neuron in your brain gets hit, do you come back being a blithering idiot, or not?
NASA appears to be hard at work studying the effects of long-term radiation in space. For example:
"Fred" the Phantom Torso -- "part-dummy, part dosimeter-imbedded torso [that] is a mock-up of a human's upper body, minus a set of arms" -- was flown to the ISS and set up in Node 2 (the attachment point for the US Laboratory). Its purpose: to yield a more accurate portrait of human radiation exposure in the station.
Thanks for taking one for the team, "Fred" -- if that is your real name.

Commercial space travel is still a bit pricey for my pocketbook. Thus, the bottom line for me is pretty simple: don't log an excessive number of polar flights. Chances are that my travel budget (and increasing gas prices) will help to keep that under control as well.

Off to the AUR Meeting in Seattle

Postings may be infrequent here for the next week.

The Samurai Radiologist will head for the Upper North Left for a week of feasting, chest-beating and muted glory at the annual meeting of the Association of University Radiologists.

Academic radiologists of all ilk will huddle together around the fire, tell their tales, perform arcane rituals, swap trade goods and propitiate the gods for another year of adequacy (plenty would be nice, but is pretty unrealistic).  

Perhaps some of the tales gathered there will be worthy of retelling here.

Saturday, March 22, 2008

Seeing An Apple Logo May Increase Creativity

Researchers at Duke University and the University of Waterloo have just released the results of a study which suggests that people may behave differently after being exposed subliminally to a brand's logo.
Automatic Effects of Brand Exposure on Motivated Behavior: How Apple Makes You “Think Different”. GrĂ¡inne M. Fitzsimons, Tanya L. Chartrand, Gavan J. Fitzsimons. Journal of Consumer Research, Vol. 35, June 2008. Electronic version published March 4, 2008.
In this study, subjects exposed to the Apple logo for just 30 milliseconds exhibited more creativity than subjects similarly exposed to an IBM logo.

Interestingly, one of the study's authors
replaced his Thinkpad with a Mac three months ago. “I figure I’ll be walking by it everyday and sometimes I’ll see it without thinking,” he tells us. “I felt like if I really believe this stuff, I should put my money where my mouth is.”
This has inspired me to start planning a randomized controlled trial using my residents and medical students as guinea pigs. The question I want to answer: "Which will make them act smarter: staring at a brain MRI or a barium enema?"

(via Fake Steve Jobs and the Wall Street Journal)

Friday, March 21, 2008

Anatomy You Don't Learn in Med School

Despite my job title, I am actually an applied anatomist by trade. I've spent years stuffing an atlas of the human body into my brain. I now spend my days comparing that atlas with the anatomy that walks into my office daily in the form of patients.

After doing this job for 20+ years, I thought I was starting to get a pretty good handle on things. However, I just ran across some sites that show me how much more I've got to learn. A few of the items now on my catch-up list:

(via Street Anatomy)

Thursday, March 20, 2008

Life Through X-ray Specs

Crookes_tube_xray_experiment-Wikipedia-cropped.jpg has a ongoing series of PhotoShop contests with various themes. Not surprisingly, many of my favorites images there are from their 6-contest series on X-Ray Vision.

My current faves:
The mother and child in X-Ray Vision 1

Pamela Anderson, the rattlesnake and the popsicle in X-Ray Vision 2

The horse and the hand holding a mouse in X-Ray Vision 3

The sheep in X-Ray Vision 4

The Coke bottle in X-Ray Vision 5

The Coke truck in X-Ray Vision 6

Wednesday, March 19, 2008

The Last X-ray I Ever Took...

I recently ran across an online contest for "The Last Photo I Ever Took". It contains some hilarious PhotoShop work.

This gave me the idea for a radiology variant: "The Last X-ray I Ever Took...". Below is a quick kludge I cranked out with my own copy of PhotoShop. If anyone has similar images, I'll be glad to post them (if you own them) or link to them (if you don't) here.


Tuesday, March 18, 2008

Grand Rounds - Vol 4, No. 26

Hot off the press!

This week's edition is hosted by physician and comic book connoisseur Scott on his Polite Dissent blog.

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

My contribution to this gathering concerns (oddly enough for a radiologist) an aspect of clinical medicine practice -- the concept of minimally interrupted cardiac resuscitation: "Is a Radiologist Doing CPR Like a Pig with a Wristwatch?".

Gosh, I'm Glad I'm Not a Dermatologist

Three, count 'em, 3 reasons why I'm not in the skin trade:

Artist: 'I Use My Skin as a Canvas' (via Kevin, M.D.)

A Rare Disorder: Stretchy Skin

Tree man 'who grew roots' may be cured

Monday, March 17, 2008

That's iPod Shuttle, not Shuffle

Automobile commuters are not the only ones who make their daily drive with an iPod up on their dashboard. The photo below was cropped from this hi-res photo of the Space Shuttle Endeavour, currently docked at the International Space Station in low earth orbit.

For more details of what it takes to get an iPod into space, see this story on The Unofficial Apple Weblog.

(via The Secret Diary of Steve Jobs)

X-rays in the Comics

I just ran across the excellent Polite Dissent blog, featuring comics and medicine, among other things.

A search of this blog's archive yields a number of examples of X-rays making it into the comic books.

The Horror of "Lead Lung Disease"

Health Care the Richie Rich Way

Superman using his X-ray vision on Sensor Girl

Dr. Kildare Reminds You to Get Your Annual Fluoroscopy Exam

A plain film of the skull showing Huntington's disease

A cervical spine film of The Phantom

Top Five Most Common Comic Book Writer Medical Errors -- see the section on Bad Radiology.

Delivering Bad News the Comic Book Way -- apparently X-rays are helpful for this.

Find Your PACS System in this Cartoon

Most radiologists now store and view their images via a picture archival and communications system (PACS).

When I first saw this cartoon, I knew immediately which panel reminded me the most of the user interface for my hospital's PACS system.


(Via Daring Fireball)

Sunday, March 16, 2008

Is a Radiologist Doing CPR Like a Pig with a Wristwatch?

ResearchBlogging.orgI've been taking cardiopulmonary resuscitation (CPR) classes periodically since medical school many years ago. For me, one of the hardest part of these classes has been keeping track of the ever-changing Official Ratio™ of chest compressions to breaths. Is it 5:1? 15:2? That's one reason why the following recent study in the Journal of the American Medical Association (JAMA) caught my eye:
Bobrow, B.J. (2008). Minimally Interrupted Cardiac Resuscitation by Emergency Medical Services for Out-of-Hospital Cardiac Arrest. JAMA, 299(10), 1158-1165.
This study compared standard advanced life support with a new protocol known as minimally interrupted cardiac resuscitation (MICR). The results: patients treated with MICR were at least 3 times more likely to survive their cardiac arrest than patients treated with the standard life support protocol.

Just what is MICR and why should it make such a difference?

The main idea behind MICR is that the "C" in CPR is a whole lot more important than the "P" part. Unlike the mixture of chest compressions and assisted breaths given in standard CPR, the MICR protocol starts off with 200 uninterrupted chest compressions. Electrical defibrillation was not performed until after these initial 200 chest compressions. Why do it this way? As the authors state:
During resuscitation efforts, the forward blood flow produced by chest compressions is so marginal that any interruption of chest compressions is extremely deleterious, especially for favorable neurological outcomes. Excessive interruptions of chest compressions by prehospital personnel are common. Therefore, MICR emphasizes uninterrupted chest compressions.
In other words: CPR is a very poor substitute for an actual heart. Interrupting chest compression downgrades this "poor" to "piss poor".

But what's the benefit of not ventilating a patient?  How does a patient get any oxygen if one omits the "pulmonary" part of CPR?
...positive pressure ventilations during cardiac arrest may be harmful because they increase intrathoracic pressure, thereby decreasing venous return and subsequent myocardial and cerebral blood flow. Probably due to the excitement and stress of resuscitation efforts, excessive ventilations by both physicians and EMS personnel are common.
Immediately after a sudden VF cardiac arrest, aortic oxygen and carbon dioxide concentrations do not vary from the prearrest state because there is no blood flow and oxygen consumption is minimal. Therefore, when chest compressions are initiated, the blood flowing from the aorta to the coronary and cerebral circulations provides adequate oxygenation at an acceptable pH. At that time, myocardial oxygen delivery is limited more by blood flow than oxygen content. Adequate oxygenation and ventilation can continue without rescue breathing because the lungs serve as a reservoir of oxygen that allows adequate oxygen exchange with the limited pulmonary blood flow during cardiopulmonary resuscitation...
In addition, substantial ventilation occurs from chest compression–induced gas exchange (ie, small volumes exhaled with each compression and inhaled with chest recoil) and spontaneous gasping by the patient in cardiac arrest during cardiopulmonary resuscitation.
Is it time to change the way we do CPR? Maybe. Maybe not.

This is a nicely designed prospective study with a large sample size (n = 883), and published in an English-language major medical journal. I commend the authors for this excellent work and am impressed by their results. However, this JAMA article has a major flaw: the CPR protocols used were not randomized. Lack of randomization can allow all sorts of bias to creep into a study. For example, the effects seen in this study could even represent an example of the Hawthorne effect. I don't think I can improve on the authors' own conclusion:
These results need to be confirmed in a randomized trial.
I agree. If a randomized controlled trial corroborates the findings in this study, I expect to see a lot of changes in official CPR protocols. For an excellent further commentary on this study, please see this JAMA editorial.

At this point, you might be wondering: "How can CPR possibly matter to a radiologist?"

If so, 5 points for Gryffindor for raising that question. But just 5.

A fair number of radiology procedures involve injecting some contrast agent (lay term = "dye") into a patient. Cardiac arrythmias are an uncommon but known complication of these agents. Thus, these studies are only performed when a radiologist is around to monitor the exam and treat any adverse reactions, including cardiac arrest.

I haven't had to do CPR on a patient since I entered radiology. However, a friend had a cardiac arrest before my eyes at a dance last year. Fortunately, CPR and a nearby automatic external defibrillator (AED) were enough for me, my spouse and several other pals to restart my friend's heart, which is still beating strong at local dances 15 months later.

I guess you could say this event made CPR really, really relevant to me -- relevant not only as a physician, but also as a precocious geezer and potential CPR customer myself. These days I travel to local dances with a personal AED just in case cardiac lightning strikes again in my vicinity. If it does, I'm also going to pay a lot more attention to my chest compressions, and keep them as uninterrupted as possible.

Friday, March 14, 2008

Deep in the Heart of Pi

Q. What's so special about the following 3 numbers: 14,457, 102,839 and 1,342,284?

A. At each of these decimal positions in Pi, one can find the U.S. Zip Code of one of my favorite areas in Austin, Texas.

Likewise, if you dumpster-dive down to the 7,724,879th digit of Pi, you'll find today's date: 3-14-2008, also unofficially known as Pi Day, 2008.

Going this deep sub-Pi without supplementary oxygen is one of those areas of math where a B.S. in Google beats a Ph.D. in math any day. Googling "digits of Pi" will take you on some great trips, including one to the excellent Pi Search Page. This site lets you quickly sift through the first 200 million digits of Pi for your phone number, your spouse's birthday, your debit card PIN number and lots of other swell numbers.

Just for laughs, check out the 3D pun at bottom of this page, or the well-named website at:

For other pieces of intellectual Pi, have a look at the Joy of Pi page. Also, visit the Wikipedia page on Pi, where you'll find delights such as the following wonderful graphic (visit the original page to see this in full size and in motion):

What does Pi have to do with radiology? Beats me. Even googling "pi radiology" doesn't turn up much besides one radiologist named "Pi" and a bunch more who happen to be PI's (principal investigators on research grants).

Anyhow, take a second today on 3/14 at 1:59:26 p.m. to celebrate this transcendental constant with what else -- Pie! I'm thinking apple, cherry or marionberry, myself.

Wednesday, March 12, 2008

Vector Map of Middle Earth

When my son was 6 years old, I read all four volumes of J.R.R. Tolkien's The Hobbit and The Lord of the Rings to him as part of our bedtime reading. It took months to finish them all, but we had a wonderful time. One of my favorite memories of this marathon was the night we read the scene where Bilbo finds the Ring in Gollum's cave. As the action mounted, my son became increasingly restless, and by the end of the chapter, was practically sitting on my head, scanning the room like a lemur, with eyes as big as saucers.
"What's the matter?" I asked.

"Your Gollum voice was
reeaallly scary!"
I flashed back to that scene tonight while reading Tim Bray's Ongoing blog. He is currently reading LOTR to his 8 year-old son, and printed out the wonderful MearthMap Map of Middle Earth as a companion to the book. As he says,’s astounding. It’s in vector format (a 1.2M PDF), which means effectively infinite scaling, which it turns out you really need if you want to be able to locate Dimrill Dale or Durthang. I extracted just the part of the map where the action occurs and printed it out on a huge glossy sheet of paper and it was a fine companion to the story.
It is, indeed, a lovely map. I've got it stashed away on my hard drive against future need, which will hopefully be sometime before my son graduates from high school. This past December, I got new hope that that might actually come true. New Line Cinema announced that Peter Jackson will indeed be filming not only The Hobbit but also another LOTR prequel. If they stay on their proposed schedule, it looks like we will be needing that map around 2010 - 2011 when the films are released.

Of course, after we watch them, we'll have to keep the map out a bit longer, while we watch the entire LOTR cycle all over again on DVD, possibly even in HD.

Obsolete Radiology Skills

The Obsolete Skills blog has a large compendium of skills that are, well, obsolete. (via Daring Fireball)

A partial list of the items collected there:
  • Dialing a rotary phone
  • Putting a needle on a vinyl record
  • Changing tracks on an eight-track tape
  • Shorthand
  • Using a slide rule
This got me to wondering what a similar list of obsolete skills for a radiologist might look like. Here are some of my random conjectures:

Obsolete radiologic procedures (a very partial list):
A pneumoencephalogram, circa 1919

Film skills dying out due to the move to digital imaging (some are not yet completely dead):
  • exposing, developing, duplicating, hanging or interpreting actual films
  • recovering silver washed out of film emulsion during developing
  • using a "hot light" to view really dark films
  • using a goniometer to measure scoliosis angles on spine films
  • photographing films for scientific publications
  • giving lectures with 35 mm slides and a projector
Measuring the Cobb angle in a spine with scoliosis

Snarky things that might be listed by non-radiologists:
  • using a stethoscope
  • remembering how to do a physical exam
  • having any clinical skills whatsoever
Anyone working in medicine for very long will have no trouble thinking of plenty more examples in all three categories. Feel free to add others to the comment section for this post.

Tuesday, March 11, 2008

Grand Rounds - Vol 4, No. 25

The latest issue of Grand Rounds (4.25) just hit the newstands on Canadian Medicine.  This episode is filled with tasty tidbits guaranteed to keep me from my regular chores.

Grand Rounds is a weekly anthology of the best writing from the medical blogscape.

One of my posts, titled Music Made Visible, is listed under the section on "Sexing up the fMRI Dossier".

Monday, March 10, 2008

Striking a Blow Against Breast Cancer

It is every physician's duty to help prevent cancer. For radiologists, this usually involves imaging patients with mammograms, chest X-rays, CT and MR scans. However, we are always delighted to learn from the media of low cost, low tech and zero-radiation alternatives that might reduce the risk of breast or prostate cancer. This news is especially intriguing when the suggested therapeutic tools are, respectively, fellatio and masturbation. (via M.D.O.D)

These are research topics where achieving an adequate sample size just doesn't look like it's going to be a problem. A call for research subjects will attract long lines of not only patient volunteers, but also of medical researchers themselves, all willing to put themselves in the hands, so to speak, of science. Even a (ahem) hardened skeptic would be happy to extend the benefit of a doubt to this kind of research.

There's really no reason why you shouldn't go ahead and launch your own personal in-depth study of these pleasant hypotheses. However, before you apply for federal funding or publish your results, a bit of fact-checking would be a handy next step. As the saying goes, "great claims require great proof". These claims are, indeed, great. Really, really, really great. If they're true.

For example, take the first report: "Fellatio may significantly decrease the risk of breast cancer in women". Gosh, if it's on CNN, there must be something to this. Not only that, the page includes related links to the New England Journal of Medicine, and the American Cancer Society.

Well...... no. If you carefully examine the URL for this report, you find that it's actually hosted on the site of some dude who may not actually work in journalism at all. The researcher's name does not turn up in a PubMed search. Googling the name of the "researcher" turns up a much more believable tale -- that this page was a spoof posted by a college student, who apparently
"responded to legal threats by apologising for the false report to his university and to CNN and to "all men who did not take advantage of this article in time ..."
Harumpf. At least one can still make a convincing case for breast palpation among consenting adults.

Next, let's examine the claim that "Masturbation 'cuts cancer risk'". This time though, the link is to the genuine BBC news site. As in the first example, a researcher's name and institution are given -- this time, however, a PubMed search does actually lead to a paper on this topic from a leading English-language urology journal, titled: "Sexual factors and prostate cancer." The abstract is a bit terse, but delivers the following summary:
Ejaculatory frequency, especially in early adult life, is negatively associated with the risk of prostate cancer.
Gosh, this is sounding better and better all the time! However, a True Skeptical Warrior™ should exercise a bit more due diligence than just reading the abstract.

A perusal of the actual paper itself adds further evidence to the authors' claim. The study population of 1079 cases and 1259 controls would seem to be an exemplary sample size. The authors describe numerous confounding variables they controlled for, supportive evidence from other papers, and several potential (and testable) biological mechanisms whereby whacking off may also whack off some of the cancer risk.

Let's hear it for real science.  It would seem that things are looking promising for a Charge of the Onanist Brigade. Gentlemen, start your engines!

However, replication of results is the cornerstone of science, and is especially important before drawing any causal inferences, even from a reputable study like this one.

A bit more searching on PubMed turns up the following subsequent study: "Ejaculation frequency and subsequent risk of prostate cancer." This much larger study looked at 29,342 men, with 222,426 person-years (or wanker-years, if you will) of followup, and, alas, shows no relation between ejaculation frequency and the risk of prostate CA. I suppose that men will just have to look for other research that will support this kind of use of their therapeutic tools.

But, hope springs eternal that science will find and validate other reasons why we should all have a lot more sex a lot more often. Bettina Arndt of the Sydney Morning Herald has written a delightful article on this topic, and points out several other hypotheses we might as well test while we're at it, such as: "ogling breasts makes men live longer" and "regular sex helps to avoid colds".

Just for the record, I am generally opposed to all forms of quack medicine. However, if one must indulge, this kind is hard to beat.

Saturday, March 8, 2008

Imaging Mount St. Helens

Since Mount St. Helens blew its top in 1980, the U.S. Forest Service and the U. S. Geological Survey have kept a pretty close eye on this particular piece of Washington State. As far as I know, they aren't using X-rays on the volcano, but the images they are producing are still quite wonderful.

The U. S. Forest Service mounted a real-time web cam in September, 2004, aimed right down the throat of the volcano. In June 2007, they added a High Definition webcam to the site, with significantly improved images.

In 1992, Johnathan Lees (now a professor of geolocial sciences at the University of North Carolina, Chapel Hill) obtained tomographic images of Mount St. Helens. Instead of X-rays, he used P-wave seismic tomography to produce 3D velocity maps of the magma system beneath the mountain. Another big imaging difference: pixel size. In medical imaging, an image pixel typically represents a piece of tissue less than a millimeter in width. Lees' pixels were much less wimpy -- the smallest of them represented a chunk of the Earth 0.5 kilometer in width! The image below shows a tomographic slice from a 27.5 x 21 x 20 km target volume. For scale, the above-the-ground profile of the volcano has been drawn in green at the top of the image.

Lees, J.M., The magma system of Mount St. Helens: Non-linear high resolution P-wave tomography, J. Volc. Geoth. Res., 53 (1-4), 103-116 1992.

Since the big boom in 1980, St. Helens has continued to erupt. In the past 3 years, the volcano has progressively added 100 million cubic meters to the lava dome in its crater. However, this latest eruption has been so gradual that normal movies of it would be like watching grass growing, only not as exciting. Instead, the USGS created a time-lapse movie of this eruption from data collected between October 2004 and July 2007. (via Ars Technica).

What's in store for Mount St. Helens next? Will someone figure out a way to use MR or PET on the mountain? Perhaps we can harness gravity waves or neutrinos to create tomograms of the whole darned planet. If so, I'd pay cash money to see that.

Thursday, March 6, 2008

iPhone SDK -- Not Just for Radiologists

iPhone fans everywhere rejoiced as Apple today released its software developer kit (SDK) for the iPhone. Hopefully, third-party applications will become available with the release of the iPhone 2.0 update in late June 2008. The free beta iPhone SDK is available immediately.

MacWorld editor Jason Snell's liveblogged today's Apple iPhone Event. Apparently, a few weeks before today's release, Apple did a very cool thing: they
... called up a handful of companies, and asked them to send out a couple of engineers each, to see what they could accomplish in two weeks on an SDK they'd never seen before. In fact, most of them had never touched a Mac for development before.
A number of these nifty applications were then shown to the crowd. One of my faves:
10:41 PT: In two weeks, they wrote a game, Touch Fighter. OpenGL game, OpenAL for audio. Using accelerometer to fly the ship by moving the phone, and tap on the screen to fire.
I'm not big on gaming, but can imagine using this same technology to fly through a 3D CT scan like the one below, by banking my iPhone back and forth. I'll bet that the mighty radiologist-programmers at OsiriX are already licking their chops at the thought of this. IMHO, an iPhone-based medical image viewer would immediately launch a lot of iPhones into the hands of not just radiologists, but practicing physicians of all ilk.

10:56 PT: Next: Epocrates. "Every doctor knows about Epocrates." Now Glenn Keighley from Epocrates. Shows a drug lookup UI, so doctors can find a drug, tap to view information about the drug. They used SQLite to store their drug data, and used the iPhone's high-resolution screen to show drug images for the first time on any mobile platform.
This will be the killer iPhone app for my spouse, a clinician who uses Epocrates daily when writing prescriptions.

Just 3 and 1/2 more months -- Woot! Woot!

Driving While Under the Influence of fMRI

What will someone cram into an fMRI machine next? Earlier this week I posted about the use of functional magnetic resonance imaging (fMRI) to study brain activity in keyboard musicians while they were improvising jazz. It would now appear that even drivers with cell phones are not safe from fMRI researchers.

Brain Research just posted an in-press manuscript titled: "A decrease in brain activation associated with driving when listening to someone speak".

Why was this study done?
"Behavioral studies have shown that engaging in a secondary task, such as talking on a cellular telephone, disrupts driving performance. This study used functional magnetic resonance imaging (fMRI) to investigate the impact of concurrent auditory language comprehension on the brain activity associated with a simulated driving task."
Despite the title of the article, they did not study actual driving -- the sheer size of a decent fMRI scanner precludes this. To see the difficulty, imagine driving down the road with a your head stuffed inside a roll of toilet paper that is 7 feet in diameter. By the way, the toilet paper roll also weighs several tons, and has magnetic and radio frequency fields strong enough to send a cell phone flying and frying. Understandably, the investigators chose to simulate driving and cell phone conversations by other means.
"Participants steered a vehicle along a curving virtual road, either undisturbed or while listening to spoken sentences that they judged as true or false. "
How did the simulated drivers do?
"The dual task condition produced a significant deterioration in driving accuracy caused by the processing of the auditory sentences. At the same time, the parietal lobe activation associated with spatial processing in the undisturbed driving task decreased by 37% when participants concurrently listened to sentences."
The bottom line:
"The findings show that language comprehension performed concurrently with driving draws mental resources away from the driving and produces deterioration in driving performance, even when it does not require holding or dialing a phone."
This conclusion is not exactly a bolt from the blue -- they cite a number of other studies that echo the same conclusion: your driving sucks when you use a cell phone, hands-free or not.
For the full article, please see: Marcel Adam Just, Timothy A. Keller, Jacquelyn Cynkar. A decrease in brain activation associated with driving when listening to someone speak. Brain Research (2008), doi: 10.1016/j.brainres.2007.12.075.
(via MedPage Today)

Wednesday, March 5, 2008

X-Rays and Bayes

Most radiologists hate statistics. Heck, most of the people I know with higher education and any sense are still nursing a deep grudge against what little statistics was crammed down their throats years ago. Since I actually enjoy number crunching and data analysis, I am considered somewhat of an outlier in my specialty.

It's becoming harder to be a competent physician these days without some familiarity with basic stats. Even in a show-and-tell field like radiology, one needs to know advanced statistical techniques to fully comprehend at least 20% of the articles in the two major U.S. radiology journals. This statistic is probably much higher in the more fundamentalist specialties, such as internal medicine, where randomized, controlled double-blinded studies are considered holy writ.

Why do people get turned off by statistics? Could it be the dense jargon? The plethora of oddly-named statistical tests? The awkward way that one has to phrase and interpret a simple freaking hypothesis test?

For example, consider the following hypothetical exchange (pun intended) between a clinical researcher and a classical statistician:

Q. Which is more effective -- treatment A or treatment B?

A. The null hypothesis that treatment A is not more effective than treatment B is rejected at the 5% level, i.e. P = 0.05.

Q. Er, um, so in other words, there's a 95% chance that they are different?

A. No. It means that if we were to repeat the analysis a bunch of times, using new data each time, then we would only falsely reject the null hypothesis 5% of the time if it were really true.

Criminy. Even radiologists, normally the Jedi Masters of the weasel word, would be ashamed to hedge this badly in one of their dictations.

Fortunately, there is an alternative -- Bayesian statistics -- that allows one to reject the "reject the null hypothesis" school of statistics and couch hypotheses and conclusions in more familiar terms. Like standard English. The name "Bayesian" comes from Thomas Bayes, a Presbyterian minister and mathematician who died in 1761. His eponymic theorem forms the basis for Bayesian inference, and was published in 1764 by a friend, after Bayes' death.

Hmmmm.... 1764 you say? If this theorem is so darned useful, why didn't we start using it a bit sooner than now?

The main reason seems to be that crunching numbers the Bayesian way can be computationally intensive. By "computationally intensive", I mean "impossible without a computer". Even with today's swift computers, techniques such as Markov chain Monte Carlo (MCMC) can eat up a lot of CPU time.

For those of us who are not statisticians, a Who's-Best argument between classical (frequentist) and Bayesian statisticians can sound a lot like a group of Plain-Bellied and Star-Bellied Sneetches. However, there do seem to be a number of potential benefits to adopting the Wayes of Bayes. To help you decide whether you wish to care further about this topic, there is a very nicely written and non-quantitative (and free) primer online:  Primer on Bayesian Statistics in Health Economics and Outcomes Research by O'Hagan and Luce. I'm up to page 20, myself, and it's a page-turner.

For further reading, Kimball Atwood has posted a great series on the utility of Bayesian statistics in clinical research at the Science-Based Medicine blog. A good place to start reading this series would be here.

For now, I'm off to a prior engagement, probably sitting on my posterior and making my way a bit further through the maze of Bayes.

Tuesday, March 4, 2008

We Have Met the Enemy and He is Us

The title of this posting is from a quote by the possum-philosopher Pogo, by Walt Kelly. Sadly, it also echoes an occasional part of my job, when I have to look at trauma images with a question of "child abuse", "non-accidental trauma", or "domestic abuse".

My dictations on these cases are usually prosaic lists of injuries, delivered in dry doctor-talk. While precise, they usually lack the simple eloquence and impact of the following 3 images, ads by the City of Hope from February, 2008.

Please click on each image and view them at higher resolution for full impact.

He gave me this on our anniversary.
He gave me this for nothing at all.
There's no excuse for domestic violence. Talk to someone who cares.

He gave me this when he proposed.
He gave me this for nothing at all.
There's no excuse for domestic violence. Talk to someone who cares.

He gave me this for my birthday.
He gave me this for nothing at all.
There's no excuse for domestic violence. Talk to someone who cares.
Kudos to the advertising agency TBWA\RAAD of Abu Dhabi, UAE; to Martin Lever, their creative director; Sherif Galal, their art director / Iilustrator; and Martin Lever and Farrukh Naeem, copywriters, for truly outstanding work.

I highly recommend the excellent posting about these ads at Street Anatomy.  

Grand Rounds - Vol 4, No. 24

The latest Grand Rounds (issue 4.24) is now up!

The theme for this week's edition is "New Beginnings", and is hosted by Jenni Prokopy, founder and editrix of - a site for young women with chronic illness who strive to live well in spite of health-related be babes!

ChronicBabe Logo

Grand Rounds is a moveable feast that features some of the more interesting posts from the past week in the medical blogosphere.

My offering to this episode, "Radiology Eye for the Straight Guy", describes a moment from the beginning of my career.

Music Made Visible

Brain-only-fMRI-journal.pone.0001679.g003.pngHow and why did humans evolve the ability to make and hear music?

It's easy to understand how stronger muscles, sharper eyes and a smarter brain would be great survival traits. The capacity to speak makes evolutionary sense as well - just the ability to yell "Sabertooth on your left!" at the right time would be huge.

However, when we got speech, we also got a lot more than just the power to grunt a few simple words. It would seem that this skill came bundled with the ability to hear four-part harmonies and appreciate the counter-melodies of Bach. But how does that make any Darwinian sense?  What's the survival benefit of a sonata?  In The Cerebral Symphony, William Calvin opines:
I'll bet that music is going to turn out to be a secondary use of some neural structure selected for its usefulness in some serial-timing task like language or throwing -- and used in the off-hours for music.
In a recent PLOS paper, researchers used functional MRI (fMRI) to take a peek under the hood of the brains of jazz musicians.


Axial slice renderings of mean activations (red/yellow scale bar) and deactivations (blue/green scale bar) associated with improvisation during Scale and Jazz paradigms. From: Limb CJ, Braun AR (2008) Neural Substrates of Spontaneous Musical Performance: An fMRI Study of Jazz Improvisation. PLoS ONE 3(2): e1679. doi:10.1371/journal.pone.0001679
An fMRI machine measures real-time changes in brain blood flow while a subject is doing something of interest. Hopefully, this changing blood flow also closely mirrors changes in local neural activity. The end result is a 3D map of which specific cerebral wheels, gears and pulleys are turning while one, say, takes a poop or improvises on a Bach fugue.

As a researcher, I was impressed with the authors' clever study design, which put 6 professional jazz pianists (one at a time, that is) into an fMRI machine with a non-ferromagnetic MIDI keyboard. They then recorded the MIDI output from this keyboard while creating simultaneous fMRI maps of brain activity. First, the musicians played a control piece: a simple one-octave C major scale in quarter notes. They were then asked to play an improvised melody, but were restricted to the use of C major scale quarter notes within the same octave. Next, they were asked to play a pre-memorized original jazz composition, in synchrony with a pre-recorded music-minus-one jazz quartet. Finally, they were allowed to cut loose and improvise freely with the pre-recorded accompaniment.


The authors conclude:
Our results strongly implicate a distinctive pattern of changes in prefrontal cortical activity that underlies the process of spontaneous musical composition. Our data indicate that spontaneous improvisation, independent of the degree of musical complexity, is characterized by widespread deactivation of lateral portions of the prefrontal cortex together with focal activation of medial prefrontal cortex. This unique pattern may offer insights into cognitive dissociations that may be intrinsic to the creative process: the innovative, internally motivated production of novel material (at once rule based and highly structured) that can apparently occur outside of conscious awareness and beyond volitional control.
As a radiologist, I'm delighted to see cool new uses of the machines I work with every day. When I started my career, we were happy just to be able to distinguish gray matter from white matter. It now appears that we are beginning to look at some of the nuts and bolts of creativity itself.

As a musician, a part of me will continue to nurse a small, Luddite hope that we don't discover all of the brain's secrets too quickly. After working with high tech gear all day, it's great solace to retreat to the atavistic pleasures of folk music and dance -- things I can enjoy even miles from electricity. For now, I'll continue to routinely deactivate major portions of my prefrontal cortex when I'm away from work, and let my instruments and my body move through the music on cerebellar cruise control alone.

(hat tip to Medgadget, whose post, This is Your Brain on Jazz, has a much better title than mine.)

Update, 3/5/08: This PLOS paper has just been featured in USA Today. To see what a keyboard player in an MR scanner looks like, see here.