Effect Measure

In my younger days I was quite enamored of radiology as a specialty. I published some papers in that area and enjoyed reading x-rays, quite a complex task, requiring the reader to integrate three dimensional anatomy with two dimensional shadows and relate that to physiology, pathology, surgery, medicine and who knows what else. It was interesting and it was fun. The field has changed a lot since those days. For one thing, the pictures are not all two dimensional any more. First CAT scans and the MRIs have made it possible to reconstruct the two dimensional shadows, taken at a bunch of angles, into the full 3D structure. We didn’t have those things in my day, although I will allow that I probably published the first such reconstruction ever in the medical literature of what later became known as a CAT scan. (Don’t bother looking for it. It was published in some obscure Proceedings of a conference on computers in radiology.)

I was working with engineers and one of them figured out how to use a Fourier Transform technique to do this kind of reconstruction, a technique x-ray astronomers used for another purpose. Good idea, mathematically, but in those days there were a lot of troubles implementing it. The first was getting an x-ray “into” a computer. Why not use a scanner? Because there weren’t any. Well, there were some. In our lab we had one of the few, essentially a cathode ray tube and a detector on the other side. Then you needed a computer. There was almost no such thing as time sharing so you had to sign up for the beast a couple of hours at a time to take personal control of the CPU. Sometimes that was the middle of the night, but for the computer types that didn’t seem to matter. We had a PDP-9 with 48K of RAM. The 48K was really 48,000 wound ferrite core memory units and this thing took up a very large room. We booted it with punched paper tape and Fortran programs were entered on punch cards and then stored on tape. Of course someone had to write the program (Fortran IV). And for this project we needed x-rays of something taken at various angles. That’s one of the things that fell to me.

I went to Woolworth’s and bought a 99 cent plastic Lazy Susan and stuck a metal rod, dead center. Then I found some lower leg bones somewhere (a tibia and a fibula) and strapped them to this upright piece. I took this contraption to the Radiology Department where I had an appointment and we took x-rays of it, turning the Lazy Susan 5 degrees each time (today it is the x-ray tube that is rotated around the patient instead of rotating the patient). Once I had my pile of pictures I took them back to the lab, we digitized them and did our work. The rest is history (although not history that includes me getting rich from it. I never made a penny).

Notice that in all my accounts of radiology there are aren’t any live people, just pictures (and in the research work, some bones). I was pretty good with patients, but I didn’t mind the lack of patient contact. Reading x-rays was fun, an intellectual, medical and scientific puzzle and that was fine for me. Nailing that weird diagnosis was the reward and even the routine stuff was enjoyable. Today radiology is quite different. There is an entire subspecialty of “interventional radiology” that involves using imaging techniques to guide various instruments to places and then doing things when you get them there, like yanking out a gallstone. I don’t know a lot about this and I don’t want to know much, either, because the usual way for someone at my age and stage of career to find out is to come in contact with it as a patient.

And radiology patient contact is the subject of an interesting paper recently presented at the Radiological Society of North America (RSNA, a big meeting where I once gave a paper, eons ago). I read about it over at Medgadget a couple of days ago. Dr. Yehonatan N. Turner, a radiologist a hospital in Jerusalem, wondered what would happen if he appended a photograph of the patient — the real patient, not his x-ray shadow — onto the x-ray itself so the radiologist could see the face before reading the film. Here’s what it looks like:


Here’s part of the RSNA presser via Medgadget:

For the study, 318 patients referred for CT agreed to be photographed prior to the exam. The images of the patients were added to their files in the hospital’s picture archiving and communication system (PACS), a network for storage and retrieval of medical images. The photograph appeared automatically when a patient’s file was opened.

After interpreting the results of the exams, 15 radiologists were given questionnaires to gather data about their experience. All 15 radiologists admitted feeling more empathy towards the patients after viewing their photos. In addition, the photographs revealed medical information such as suffering or physical signs of disease.

More importantly, the results showed that radiologists provided a more meticulous reading of medical image results when a photo of the patient accompanied the file.

Incidental findings are unexpected abnormalities found on an image that may have health implications beyond the scope of the original exam. In order to assess the effect of the photographs on interpretation, 81 examinations with incidental findings were shown in a blinded fashion to the same radiologists three months later but without the photos. Approximately 80 percent of the radiologic incidental findings reported originally were not reported when the photograph was omitted from the file.

The radiologists involved in the study commented that while the addition of the photo did not lengthen the time spent reading, it was a factor in how meticulously they interpreted the images. All 15 radiologists agreed that the inclusion of a photograph in a patient’s file should be adopted into routine practice. The photos can also be included in long-distance teleradiology practices. (Medgadget)

Once again, this shows how complex a task it is to “read” an x-ray. Having the photo actually improved diagnosis, at least if you consider incidental findings (findings not related to the reason for taking the x-ray) improved diagnosis (we can argue about that some other time).

What do I think about this? Pretty interesting.


  1. #1 Lab Rat
    December 11, 2008

    Having a picture attached would be a great help, I would imagine, as it gives more clues to look for in disease diagnosis.

  2. #2 KeithB
    December 12, 2008

    Is it my imagination, or does the guy in the photo look like PZ?

    When I had my kidney stone blasted a few months ago I heard that they used a flouroscope to aim the sound waves, I don’t know if a radiologist was involved.