Many patients erroneously believe that x-rays and CAT scans have no risk.

In their minds, they are non-invasive studies that can cause no harm. Since there are no incisions or anesthesia, they regard the experience as having the same risk as taking a family photograph. How wrong they are.  In my mind the danger from non-invasive radiology studies may surpass the risk of hard core medical treatment. True, radiology tests won’t puncture an organ or a blood vessel, as a surgeon or a gastroenterologist can. Imaging studies do not cause direct damage, but they may lead patients onto the medical battlefield.

These diagnostic tests are an insidious force that draws patients into a spiral of direct risk and medical overutilization.

Is this post a shot at radiologists? No, it’s a shot at all of us. Remember, radiologists never order CAT scans; the rest of us physicians do. I certainly am distressed with the obsessive manner that my radiology colleagues interpret studies today, identifying innocent, tiny ‘abnormalities’ that will then light a fuse for further studies. In many of these cases, the CAT scans were ordered for defensive purposes, and the radiologists’ interpretations often keep the defensive medicine train lumbering forward.

On July 1, 2010, the New England Journal of Medicine, the most prestigious medical journal in the world, published 2 commentaries on CAT scans and medical imaging. While readers are free to review the first and second essays in the journal, I will summarize the major points here:

• Nearly 400 patients in the U.S. who underwent brain-perfusion scans are known to have received an overdose of radiation. How many folks have received a ‘brain sizzle’ that we do not know about?
• Radiation doses from CAT scans are hundreds of times higher than standard x-rays.
• There is persuasive medical evidence that radiation is carcinogenic.
• Physicians like me who order scans have limited knowledge of radiation doses and toxicity.
• Technology exists and can be further developed to reduce radiation exposure to patients.
• There are no evidence-based standards on the proper role for medical imaging tests. It’s a free for all.
• CAT scans are overutilized. Amazingly, about 10% of the U.S. population undergoes a CAT scan each year.  So far, I’ve never undergone one.  How much longer can I hold out?
• Individual patients should have their radiation exposure history tracked.
• Physicians often order CAT scans and other imaging studies believing this will lower their risk of being sued for medical malpractice.  I can vouch for this in my own experience.
• Radiologists, also seeking to lower their legal risk, routinely identify insignificant abnormalities and advise that these ‘lesions’ be evaluated and scanned in the future to verify that they have not changed.
• Effective tort reform is one mechanism to reduce the number of unnecessary imaging tests.
• Scans are routinely ordered when the probability that the disease exists is low. I have addressed the consequences of this approach in a prior post.
• Radiologists serve as technicians, rather than serve as medical consultants to assist clinicians.
• Medical students are not trained to rely upon medical evidence with regard to imaging tests. Bad habits learned in medical school tend to be sustained throughout a career.

CT scanning, and related medical technologies, are towering milestones that have revolutionized the medical profession.  They have eliminated millions of exploratory surgeries and have allowed physicians to make and exclude various critical diagnoses.  We couldn’t function without them.  Nevertheless, CT scan overuse is rampant, and there are no forces that are curtailing or guiding its use.  We are spending billions of dollars on scans that are not medically necessary.  I have ordered some of these scans personally, so I acknowledge that my own practice needs remediation.

We describe medical imaging tests as non-invasive, but this is deceptive.  First, there is direct risk of harm from accumulated radiation exposure.  Secondly, and more importantly, there are the indirect consequences.  For many patients, the radiology suite is a danger zone, a trap door that can drop patients into a medical cascade with no way out.

Michael Kirsch is a gastroenterologist who blogs at MD Whistleblower.

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