Q I am astounded to see that you have an MRI. I know veterinary medicine has advanced over the years, but an MRI? Thatís amazing, but at the same time I wonder if all these advances just unnecessarily drive up the cost of veterinary medicine and donít add much to what can actually be done for a pet. What can you do with that that you could not have done before you had it?

A. We definitely have the most discerning readership of any column and this question proves it.

Your question goes to the heart of what also is a major problem in human health care. Tests and imaging modalities, such as CT scans and MRIs have advanced to the point where we can visualize tissues to an almost microscopic level. Noninvasively, we now acquire detailed information about the state of internal structures such as our hearts and brains with astounding clarity.

But have we as clinicians become too reliant upon advanced imaging and in doing so become soft in our diagnostic aptitude? To some degree I (Dr. Bianucci) would say, yes.

In our litigious society, clinicians have a fear of making a mistake or missing something on an examination. Listening to the chest with a stethoscope is good, but an X-ray may pick something up that cannot be heard, so a doctor can order a chest X-ray and have it read by a radiologist.

If something is missed now, itís the radiologistís fault. My daughter was on a ship 10 miles out to sea in rough weather and she hit her head. She never lost consciousness and although she did get sick to her stomach, so did everyone on the ship. She presented to the ER a full 12 hours later. She had a headache, but no neurologic deficits and was feeling better.

The doctor ordered a pregnancy test and a CT scan among others. I refused the CT because, in my opinion, the odds that it would diagnose anything that would change our treatment course were minimal and the known exposure of radiation is high.

The problem for the doctor is that if something had been there and missed because a CT was not recommended, he would have been on the hook.

So, the availability of advanced diagnostics, fear of litigation, and possibly the desire for increased revenue may be driving our costs way above what they would be with a thorough physical examination coupled with sound clinical judgment.

For example, the Journal of the American Medical Association reported in one study that in 1996, CT scans were performed at a rate of 52 per 1,000 cases and by 2010 the rate had jumped to 147 per 1,000 cases.

In another report, it was revealed that in one Iowa community of 300,000 people, 52,000 scans were performed in one year. The conclusion of that study was that CT scans were being widely over-prescribed.

One major problem with overprescribing CT scans is not only elevated cost, but the real risks associated with radiation exposure from scans. One skull CT scan can expose the patient to radiation equivalent to 250 to 400 chest X-rays. This is especially dangerous for children as their developing brains are more sensitive to radiation exposure, increasing their risk of cancer development.

MRI stands for magnetic resonance imaging. The technology takes advantage of the fact that our tissues contain varying amounts of water and thus hydrogen ions (H20). It works, in quite simple terms, by exposing the patient to a large magnet. The magnet causes the ions to spin and create a magnetic field that the scanner can detect.

This is reconstructed into a high resolution image, unmatched by other imaging techniques such as CT scans or conventional radiographs. There are no proven health risks associated with MRI, as no ionizing radiation is used. So, MRI provides superior soft tissue imaging and safety.

Our neurologist, Dr. Peter Brofman, explained, ďMRI allows us to evaluate subtle changes in tissue composition.Ē

In cases of spinal cord trauma, the appearance of the cord on an MRI is a better prognostic tool than physical examination or other imaging techniques. This has enabled us to help owners make better decisions about surgery or other continued treatment for their pets.

Brofman went on to describe a recent case of a small dog with severe spinal pain. Suspecting a disc injury, an MRI was performed. Although there was a disc bulging, he judged that it was not large enough to cause the level of pain he was seeing, and the MRI revealed changes in the adjacent tissue that was consistent with an infection.

Prior to MRI imaging, this would have been diagnosed as a disc problem, and possibly had an unnecessary surgical procedure performed.

As it was the patient, responded to rest and antibiotics. ďPrevious imaging would have shown a disc or, in some cases, nothing. Leaving us scratching our heads or doing the wrong procedure for the case.Ē

So although an MRI is more expensive, itís preferable to the cost of an unnecessary procedure or an undiagnosed condition. As with any diagnostic choice, it should be selected to confirm or deny a diagnosis based upon thorough physical examination and clinical judgement.

Its findings should be expected to alter your treatment plan. Used in that manner, it is an extremely powerful and beneficial tool.

Dr. Henri Bianucci and Dr. Perry Jameson are with Veterinary Specialty Care LLC. Send questions to petdocs@postandcourier.com.