The Radiologist’s Bad Miss

August 7, 2015

A miss in radiology is inevitable; you just have to be lucky.

You know what I'm talking about. Don't deny it. A doc comes by to review a CT. The scan shows a large nasty looking pancreatic mass with vascular encasement and liver mets. The doc says, "Hey, didn't this guy have an abdominal CT eight months ago? Was this thing there?" Warily, you open the prior exam. You scroll to the pancreas. There, practically jumping off the screen, is an obvious pancreatic mass, though smaller and without liver mets or vascular encasement. It looks as big as a beach ball to your eye. Someone couldn’t miss this, could they? You glance at the report. No mention of the mass. You glance at the doc. You think to yourself, "Doesn’t he see how obvious this thing is?" He doesn't appear to see it.

You scroll off the pancreas. You start to hem and haw, "Well, there was motion artifact, the study wasn’t a dedicated pancreas protocol, the bolus timing was suboptimal, it’s hard to see if there’s anything there, blah, blah, blah." The doc leaves. You feel dirty. You tell your partner about their miss. They feel like crap. They notify their carrier. Maybe they notify hospital risk management. They wait for the lawsuit that may or may not come.

What should you have done? Should you have told the referring doc that this thing should have been seen? What good would that do for anyone? Does your hospital have a policy on disclosure of medical errors? If it does, do most docs actually follow it? Could you have missed something this obvious yourself? If you’re being completely honest, the answer to at least the last question should be a yes.

Just think about the numbers. The average radiologist reads approximately 15,000 cases per year.1 According to multiple studies, radiologists will misinterpret approximately 3%–5% of unselected cases and 30% of cases with positive findings.2,3,4 Doing the math (assuming the approximately 4% error rate in unselected cases), an average radiologist (but, like the children of Lake Wobegon, aren't we radiologists all above average?) will misinterpret about 600 cases per year, each one potentially representing a successful malpractice claim.[[{"type":"media","view_mode":"media_crop","fid":"40167","attributes":{"alt":"","class":"media-image media-image-right","id":"media_crop_2271272627676","media_crop_h":"0","media_crop_image_style":"-1","media_crop_instance":"4085","media_crop_rotate":"0","media_crop_scale_h":"0","media_crop_scale_w":"0","media_crop_w":"0","media_crop_x":"0","media_crop_y":"0","style":"height: 150px; width: 200px; float: right;","title":"©Dooder/Shutterstock.com","typeof":"foaf:Image"}}]]

So why aren't we being sued all the time? This is where luck enters the equation. Whether we are sued depends on numerous factors: Is the patient aware of the miss? Was the patient harmed by the miss? If it was a cancer miss, was the finding picked up on a follow up study within a short enough time interval so as to not have made a clinical difference? Is the patient (or the patient's family) litigious?

Does the mere misinterpretation of a case constitute malpractice? Well, no. Malpractice requires both harm to the patient and a breach of the standard of care by the radiologist. If there is no harm, then (as they say in basketball), there is no foul. What about the ‘bad miss’? Does missing an obvious (in retrospect) finding constitute a breach of the standard of care? This is less clear.

The courts have long acknowledged that radiologists cannot be held to a standard of perfection, and that a 'missed' or misinterpreted finding does not in and of itself constitute malpractice. As long as the radiologist is appropriately trained and exercises due diligence in the interpretation of the exam (not reading the study from 30 feet away after reading 500 cases and being up for 72 hours straight), a missed significant finding should be defensible in court according to this standard. But it’s not.

In reality, if it’s an 'obvious' or 'bad' miss, it is not defensible, and the plaintiff’s expert witnesses will testify that the miss was sufficiently egregious as to constitute malpractice. For this reason, cases involving an obvious miss of a significant finding will be settled long before they see the inside of a courtroom, a de facto admission of wrongdoing by the radiologist. But is committing an obvious miss truly malpractice? It shouldn’t be, not according to the law and not according to the science.

If you go by the research on radiology errors, numerous obvious misses are inevitable for any long-time practicing radiologist, and to deny making them is either dishonest or delusional. (Interestingly, during my training, I had several attendings that would frequently testify for the plaintiffs in malpractice cases. Lo and behold, these were the very attendings known to the residents to often miss obvious findings.)

So what is the moral of this story? Be well trained. Be diligent. Be careful. Be lucky. Did I mention ‘be lucky’? For those of you who think that the ‘bad miss’ is something that the other radiologist does, think again. The fault, dear Radiologist, lies not in our films, but in ourselves. Let those among you who is without radiographic error cast the first Dictaphone.

References

1. Bhargavan M, Kaye AH, Forman HP, Sunshine JH. Workload of radiologists in United States in 2006-2007 and trends since 1991-1992. Radiology. 2009;252:458-467.

2. Garland LH. Studies on the accuracy of diagnostic procedures. AJR. 1959;82:25-38.

3. Siegle RL, Baram EM, Reuter SR, Clarke EA, Lancaster JL, McMahan CA. Rates of disagreement in imaging interpretation in a group of community hospitals. Acad Radiol. 1998;5:148-154.

4. Borgstede JP, Lewis RS, Bhargavan M, Sunshine JH. RADPEER quality assurance program: a multifacility study of interpretive disagreement rates. J Am Coll Radiol. 2004;1:59-65.