The Value of Incidental Findings

February 22, 2018

When is a little thing a big deal?

As a trainee, it can be confusing to determine whether or how to report findings that have little significance to the clinical question. Incidental findings in radiology include a category of diagnostically indeterminate findings that need further evaluation, as well as a category of findings that have no significant clinical impact. There has been considerable heterogeneity in reporting of the latter category, and our discussion will focus on these entities. An incidental finding, such as a simple renal cyst, duodenal diverticulum, and anatomical variants require no follow-up imaging or workup. They are benign without malignant potential. They do not impact the patient’s life; in fact, no one would realize the finding existed prior to the imaging exam. The continued rise in the volume of imaging means that more incidental findings will likely be discovered, and we will need to figure out how to deal with them.


Do incidental findings really have no impact? While a finding may not have clinical significance at the time of the current imaging exam, they may become relevant in the future. Exams are now archived in electronic servers and reports are permanently stored in the electronic medical record. The ability to quickly look back at prior imaging has made a significant impact on our ability to interpret imaging findings. In this system that codes dictations as searchable key words, documenting incidental findings may be useful for long-term patient care. For example, vascular anomalies are anatomic variants that may have clinical impact at a later time. A left vertebral artery arising directly from the aortic arch may result in neurological symptoms. Furthermore, it is important to make the surgeon aware of such variants because they might impact surgical planning for neck and chest operations. Recognizing anatomic variants and their impact is essential for radiology trainees.


Are incidental findings truly harmless? The American College of Radiology Incidental Findings Committee reported that a non-enhanced CT scan of the lower chest, abdomen and pelvis may detect clinically significant incidental findings in 5-16 percent of asymptomatic patients and a higher frequency in symptomatic patients. Further workup of these findings may change clinical or surgical management only in a small percentage of patients. For example, workup of an indeterminate renal mass with CT or MRI renal mass protocol often cannot distinguish between renal cell carcinoma (RCC) and oncocytoma or lipid-poor angiomyolipomas. Therefore it is not surprising that at surgical resection, many solid renal masses are found to be benign. Even for patients with a “radiology success story,” meaning that a renal mass was worked up with imaging, followed by prompt surgical resection of a malignancy, there can be contradictory outcomes. Studies of patients with small renal masses, specifically stage T1a RCC, have shown paradoxically increased mortality after surgery. Less than optimal outcomes have led to mounting questions about the cost versus benefit ratio of recommending further imaging evaluation for each incidental finding.


Would anyone pay more to have incidental findings of little or no clinical significance reported? A medical professional would probably say no, but a patient might say yes. In our current payer system, there is no mechanism to bill for a shorter or longer read. In fact, the current movement in radiology is toward uniform dictation templates to minimize heterogeneity in our reports. Nevertheless, as more patients get scanned and more data is generated, there may be a growing market for radiology consultation or boutique radiology, where patients may get a more personal, in-depth interpretation.


Being able to distinguish benign from potentially harmful findings is an important part of radiology training. Incidental findings are commonly encountered, and deciding how to report them continues to be a daily struggle. Evaluation of incidental findings requires considering what is best for patients. A 2016 article that introduced the concept of not reporting clinically unimportant incidental findings raises an important point that physicians make better decisions when attention is focused on the most important findings. The radiologist’s number one priority is answering the clinical question to facilitate patient care, and reporting potentially harmful findings to ensure patient safety. Overall, higher-resolution imaging and better understanding of clinical significance have allowed radiologists to become an increasingly important part of the medical team.