Volume 4, Issue 3 - Special Issue: Improving diagnosis in radiology – progress and proposals / Guest Editors: Michael Bruno, Kevin Johnson, Nick Argy and Mark L. Graber

In September of 2014, the American College of Radiology joined a number of other organizations in sponsoring the 2015 National Academy of Medicine report, Improving Diagnosis In Health Care . Our presentation to the Academy emphasized that although diagnostic errors in imaging are commonly considered to result only from failures in disease detection or misinterpretation of a perceived abnormality, most errors in diagnosis result from failures in information gathering, aggregation, dissemination and ultimately integration of that information into our patients’ clinical problems. Diagnostic errors can occur at any point on the continuum of imaging care from when imaging is first considered until results and recommendations are fully understood by our referring physicians and patients. We used the concept of the Imaging Value Chain and the ACR’s Imaging 3.0 initiative to illustrate how better information gathering and integration at each step in imaging care can mitigate many of the causes of diagnostic errors. Radiologists are in a unique position to be the aggregators, brokers and disseminators of information critical to making an informed diagnosis, and if radiologists were empowered to use our expertise and informatics tools to manage the entire imaging chain, diagnostic errors would be reduced and patient outcomes improved. Heath care teams should take advantage of radiologists’ ability to fully manage information related to medical imaging, and simultaneously, radiologists must be ready to meet these new challenges as health care evolves. The radiology community stands ready work with all stakeholders to design and implement solutions that minimize diagnostic errors.

Just as radiologic studies allow us to see past the surface to the vulnerable and broken parts of the human body, medical malpractice claims help us see past the surface of medical errors to the deeper vulnerabilities and potentially broken aspects of our healthcare delivery system. And just as the insights we gain through radiologic studies provide focus for a treatment plan for healing, so too can the analysis of malpractice claims provide insights to improve the delivery of safe patient care. We review 1325 coded claims where Radiology was the primary service provider to better understand the problems leading to patient harm, and the opportunities most likely to improve diagnostic care in the future.

For the first 180 years following the founding of the US, physicians occasionally were sued for medical malpractice. Allegations of negligence were errors of commission – i.e. the physician made a mistake by doing something wrong, usually mistreatment of a fracture or dislocation, a complication or death following a surgical procedure, prescribing the wrong medication, and after the discovery of the X-ray by Roentgen in 1895, causing radiation burns. In the mid twentieth century malpractice allegations slowly changed from errors of commission to errors of omission – i.e. the physician failed to do something right: almost always, failed to make a diagnosis. The number of malpractice lawsuits increased at a geometric rate beginning in the 1960s, and in the 1970s physicians began practicing defensive medicine, which lead physicians to order unnecessary radiology exams and tests. In the past 20 years the number of malpractice lawsuits has been decreasing, but the practice of defensive medicine has continued. Unnecessary exams and tests increase the likelihood of overdiagnosis and overtreatment, i.e. a new kind of error of commission.

Perceptual errors are common contributors to missed diagnoses in the clinical practice of radiology. While the physical attributes of an image such as image resolution, signal-to-noise characteristics, and anatomic complexity are major causes of poor conspicuity of pathologic lesions, there are major interrelated cognitive contributors to visual errors. The first is satisfaction of search (SOS), where the detection of an abnormality results in premature termination of further search. Another form of incomplete search pattern is visual isolation, where a radiologist’s search pattern is truncated to the main areas of an image, while little or no attention is given to peripheral areas. A second cognitive error is inattentional blindness, defined as the failure to notice a fully visible, but unexpected object because attention was otherwise engaged. Strategies for error mitigation have centered around the use of check lists, self prompting routines, and structured reporting within an institutional culture of safety and vigilance.

Radiologists practice in an environment of extraordinarily high uncertainty, which results partly from the high variability of the physical and technical aspects of imaging, partly from the inherent limitations in the diagnostic power of the various imaging modalities, and partly from the complex visual-perceptual and cognitive processes involved in image interpretation. This paper reviews the high level of uncertainty inherent to the process of radiological imaging and image interpretation vis-à-vis the issue of radiological interpretive error, in order to highlight the considerable degree of overlap that exists between these. The scope of radiological error, its many potential causes and various error-reduction strategies in radiology are also reviewed.

In the context of diagnostic testing, concepts such as sensitivity, specificity, predictive values, likelihood ratios and more are all interconnected, but precisely how can be confusing to the nonstatistician. This paper presents a graphical explanation. Bayes’ rule, or theorem, ties several of these concepts together and should have a role in careful diagnostic thinking. It too can be understood in terms of the “two-by-two diagram” presented here.

Failure to follow-up on test results represents a serious breakdown point in the diagnostic process which can lead to missed or delayed diagnoses and patient harm. Amidst discussions to ensure fail-safe test result follow-up, an important, yet under-discussed question emerges: how do we determine who is ultimately responsible for initiating follow-up action on the tests that are ordered? This seemingly simple question belies its true complexity. Although many of these complexities are also applicable to other diagnostic specialities, the field of medical imaging provides an ideal context to discuss the challenges of attributing responsibility of test result follow-up. In this review, we summarize several key concepts and challenges in the context of critical results, wet reads, and incidental findings to stimulate further discussion on responsibility issues in radiology. These discussions could help establish reliable closed-loop communication to ensure that every test result is sent, received, acknowledged and acted upon without failure.

In medicine, data collection and analysis provide the information needed to reduce diagnostic uncertainty. An examination of how medical imaging data is collected and then transformed into diagnostic information provides testable ideas for better managing this dynamic process. In other fields, process data is systematically assessed for differences between observed and predicted values. For studies that expose patients to the potentially harmful effects of ionizing radiation, monitoring imaging studies/illness, images/imaging study and radiation exposure/image would be steps towards developing radiation dose budgets for the diagnosis and treatment of common conditions. Random variation within the expected range would signal a high quality process. Conversely, single outlying cases or nonrandom variation within the expected range would trigger an investigation for a possible underlying cause. Such investigations would provide insights into how to continually improve this important aspect of healthcare.

Diagnostic errors in radiology are frequent and can cause severe patient harm. Despite large performance differences between radiologists and non-radiology physicians, the latter often interpret medical images because electronic health records make images available throughout the hospital. Some people argue that non-radiologists should not diagnose medical images at all, and that medical school should focus on teaching ordering skills instead of image interpretation skills. We agree that teaching ordering skills is crucial as most physicians will need to order medical images in their professional life. However, we argue that the availability of medical images is so ubiquitous that it is important that non-radiologists are also trained in the basics of medical image interpretation and, additionally in recognizing when radiological consultancy should be sought. In acute situations, basic image interpretations skills can be life-saving. We plead for a radiology curriculum for all medical students. This should include the interpretation of common abnormalities on chest and skeletal radiographs and a basic distinction of normal from abnormal images. Furthermore, substantial attention should be given to the correct ordering of radiological images. Finally, it is critical that students are trained in deciding when to consult a radiologist.