Tuesday, May 13, 2008

The Radiologic Appearance of Acute Kindle-itis

If possible, my life has just become even geekier. As of 4 days ago, I am now the owner of a Kindle -- Amazon's new digital reading device.

I am not a digital book newbie. I have read books for years on my Palm -- usually in the form of bedtime reading. I have to say that a Palm screen is not the most exciting way to read a book. However, this is actually a good thing. Since my main goal with the Palm is to put myself to sleep, anything that makes the reading process more boring is actually an asset.

I was intrigued by the Kindle when it first came out, but was put off by the fact that it sold out in 5 hours and remained out of stock for months. One index of its scarcity is that to this day, I have still never seen another one in the wild. To put this into perspective, consider that I am a geeky book addict living in a city full of high tech companies and obsessive readers even geekier than I am. Having gone through the hassle of trying to buy one artificially scarce object -- the Wii -- for my son last year, I wasn't eager to go through that process again.

What changed? Amazon finally started making enough of them to meet the demand. When one of my favorite Mac podcasts mentioned that the Kindle was, at long last, actually in stock, I decided to take the plunge.

Along the way, my interest had been further piqued by Andy Ihnatko's revelatory column on the Kindle: It's About More Than Just Waffles. As usual, he nailed it: forget the official Amazon marketing. A Kindle is actually a wireless, hand-held web-browser/blog-reader with free EVDO wireless connectivity. Forever. Or, at least as long as you or your Kindle or Amazon continue to function. If you, like me, are already paying $60 / month for your iPhone or for your laptop EVDO connection, you can see what a compelling bargain this is all by itself. The fact that the Kindle also lets you buy, read and store books is a pretty nice secondary feature.

For a more visual argument for why you should consider getting one of these gadgets, the following 9+ minute video by Andy Ihnatko may do the trick. A capsule summary:
"This is the least Apple-like, least iPod-like, cool piece of techology made."

It would be hard to top Andy's reviews for why you should buy one, or MacInTouch's very complete review of what you would get for your money. Therefore, I'll swerve off in a different direction and cover the radiology angle, i.e. how it well it might work in teaching and learning radiology.


First of all, text is a non-issue. The Kindle displays text quite well, with nicely anti-aliased fonts in several easy-to-change sizes. The Kindle allows one to do standard bookish things such as placing digital bookmarks, making notes and highlighting passages. However, it also allows one to do some things that are difficult in physical books, such as looking up the definition of an unfamiliar word or searching one's whole library for a particular word/phrase/quote.


Images are another matter, and it all boils down to the particular display used by the Kindle -- a novel display technology known as electronic ink. Specifically, the Kindle uses a piece of Vizplex™ imaging film to create a 6" diagonal display with 600 x 800 pixel resolution at 166 dpi.

One of the beauties of words printed in electronic ink is that you actually read them with the device turned off. When one "turns" to a new page, the Kindle turns itself on, writes the new page, and then turns itself back off. This change from one page to the next is accompanied by a flash that can initially be rather distracting (like a visual fart, as Andy Ihnatko put it). However, it didn't take me very long before I didn't even notice this.

The screen uses actual black and white ink particles of pigment that are contained in teensy capsules within the screen. These ink particles move to different positions of a capsules when an appropriate electrical charge is applied to them. The pigments rest in their last position without power, and the display only consumes power when it changes.

The switching speed for a new page is typically about 740 msec. This is fine for reading a book, but it means that you won't be viewing video files on your Kindle anytime soon.

The result is a screen that is easy to read under indoor lights or direct sunlight. However, without some sort of external lighting, you won't be able to read it in the dark. By dark, I mean most radiology reading and conference rooms.

Vizplex supports 8 shades of gray, but according to MacInTouch, the Kindle only displays 4 of them. This is fine for displaying diagrams and line drawings. However, for those of us used to viewing images with 2^10 grays, this will be a bit of a let-down. The Kindle's workaround is to dither the images. Dithering is akin to the half-tone process used to print photos in newspapers and magazines. It has the effect of reducing spatial resolution, but fools the eye into perceiving more gray shades than are actually present. The Kindle comes with many exemplars of this, in the form of many attractively dithered images that fill its screen in sleep mode.

As an experiment, I used GraphicConverter to dither the following case of sarcoidosis of the great toe (Effect -> Black&White -> Atkinson). I then moved them over to my Kindle for viewing. Click on the following image to see three different versions at full resolution:

Original image in 256 grays, 4 grays using Atkinson dithering, and 4 grays using Floyd-Steinberg dithering.

The results? Not too shabby. Although it wouldn't fly for diagnostic purposes, the lace-like pattern of sarcoid in the distal phalanx can still be seen well enough for educational purposes. Of the two dithering modes, I think I prefer the Atkinson algorithm. Also, I have found that an image looks a lot better when it is sized large enough to completely fill the Kindle screen.

As another experiment, I moved two Word documents full of medical images over to the Kindle using Amazon's e-mail conversion service. The first document contained images embedded in Word in .jpg format. In the second document, I carefully dithered all of the images down to 4 grays with GraphicConverter and re-pasted them back into the document. I was a bit surprised (and miffed) to find that the images in my hand-optimized file sucked badly, while those dithered by Amazon's automatic online converter were actually rather decent. This means that any manuscript, review notes, case studies or personal documents in Word format can easily be transferred into Kindle format and shared.

How about radiology books on the Kindle? As of the moment, there are 263 radiology titles available in the online Kindle Store online. I picked out a few likely-looking titles and had the Store send sample chapters to my device. The text was fine, but the images in the books I've viewed so far have sucked rather badly. This suckage is due to the images being rather small relative to the Kindle display, and the fact that they seem to have been posterized rather than dithered.  This makes them look like bad paint-by-numbers X-rays.

Even with sucky images, I'd strongly consider buying a Kindle version of some of my large multi-volume reference texts, just for the ability to easily look things up in them.

Alas, Amazon's converter does not yet handle PDF files. Therefore, if I want to shove a stack of journal articles onto my Kindle, I'll first have to save then onto my Mac in HTML format and then let Amazon convert them for me.


The built-in EVDO wireless connection is very cool. I've already used this several times during lectures, conversations or podcasts. As the speaker mentions a cool book, it's amazingly seductive to search for it, buy it and even start reading it in real-time. Within minutes of hearing a great podcast book review, I was 99 cents poorer, and had all six volumes of Edward Gibbon's 1776 classic, The History of the Decline and Fall of the Roman Empire, on my Kindle, ready to read.


By and large, the interface is relatively logical and easy to learn. To turn a page, you click a large "next page" button along the right side of the screen. The left side of the screen has, alas, both a "previous page" and a "next page" button. This extra damned "next" button keeps me going to the wrong page a lot often more than I'd like. It feels a bit like the UK car rental we once got that was a perfect mirror-image of our car at home -- particularly the turn signals and windshield wipers. You can imagine how well that turned out.

Also, IMHO, these next/previous page buttons are TOO DARNED BIG! These buttons cover so much of the Kindle's edges that there isn't a whole lot left to grab. I cope by keeping my Kindle in its case. At least grabbing that won't send won't send me flying off to unexpected places.

Comparing the Kindle to the other great technological joy of my life -- my iPhone -- is both unfair and inevitable. Juxtaposing these two devices is very reminiscent of the Apollo-Soyuz exhibit at the Smithsonian National Air and Space Museum. While both devices get the job done, it's pretty easy to tell which one is by Apple and which one is the latest Soviet design.

The Bottom Line

In one short week, the Kindle has joined my iPhone as one of the two techie tools that I'm never without. The idea of killing time in a checkout line, airport boarding gate or doctor's waiting room without both of these devices has become unthinkable to me. Amazon got so many things right with the Kindle that I can live with its occasional oddities. If you are a demon reader like myself with a multi-hour daily reading habit, you inhabit the perfect demographic for this device, and it is Good Enough for That Right Now.

How about medical education? Physicians who can exist on a diet of words alone (internists, pediatricians, psychiatrists, etc.) should have no trouble learning from the Kindle. However, for us obligatory imagevores, the jury is still out. From my experiments so far, I think that there is a lot of promise, provided that great care is taken to minimize image suckosity.

Chances are that if we someday attend the same radiology meeting, I'll be the one in the back of the room reading my Kindle between talks. In case you see several of us holding one, I'll be the one grumbling about the "Effing windshield wipers!"


sanj said...

Thank you..I am a radiologist and planning to buy the kindle-had a question about getting journal articles onto the kindle-your post has handled it pretty well.
And you have also answered the problem of handling radiology images. Your effort is appreciated.
I am on my way to order the kindle on amazon...although I am disappointed that the images displayed on it will be really suboptimal.
I had one question-do you find your eyes hurt after reading on the device for more than an hour or so?

The Samurai Radiologist said...

@ sanjay

Radiology images are not too bad as long as you crop and size them so that the detail of interest fills the screen.

As long as I have sufficient light, I can read for hours at a time off the Kindle without apparent eyestrain. When the light is a bit low, I either supplement it with a portable reading light or bump the font size up a bit.

I hope that you enjoy your device as much as I have.

Unknown said...

Hi there, have you explored the IPAD yet? wondering about radiology articles there, Anita