System-related errors are commonly caused by:

1. Faulty processes*
2. Lack of knowledge
3. Cognitive biases
4. New technology

• System-related errors are the result of environmental factors such as workload, staffing, inefficient processes, communication errors, lack of teamwork, and interruptions.
• Lack of knowledge and cognitive biases can contribute to errors but are not causes of system-related errors.
• New technology is not in and of itself a driver for system-related errors. If there are errors because staff are not trained to use new technology, then the system-related cause would be faulty training policies and processes.

Which of the following is a system-related cause of diagnostic error?

1. Hindsight bias
2. Alliterative error
3. Case complexity
4. Workload*

• System-related errors are the result of environmental factors such as workload, staffing, inefficient processes, communication errors, lack of teamwork, and interruptions.
• Hindsight bias is a cognitive bias that refers to the tendency to overestimate the predictability of an event after the event is known.
• Alliterative bias is a cognitive bias that represents the influence that one radiologist’s judgment can exert on the diagnostic thinking of another radiologist
• Case complexity may be associated with more frequent errors, but is not a system-related cause of errors.

According to Siewart et al., which of the following is an intervention that can reduce diagnostic errors related to missed lymphadenopathy?

1. Dose reduction
2. Bladder opacification
3. Bowel opacification*
4. Arterial phase of enhancement

• Abnormal lymph nodes can be missed because they blend in with surrounding bowel and vasculature. Because of this, bowel opacification with positive oral contrast and vascular opacification can both make abnormal lymph nodes more conspicuous, thereby reducing errors related to missed lymphadenopathy.
• Dose reduction reduces radiation dose associated with CT exams but does not reduce diagnostic errors.
• Bladder opacification can make recurrent bladder and prostate cancer more conspicuous, but does not reduce errors related to missed lymphadenopathy.
• Adding an arterial phase of enhancement to a contrast-enhanced study does not provide added benefit in identifying lymphadenopathy.

A patient undergoes surveillance imaging after nephrectomy for renal cell carcinoma (see image below). The interpreting radiologist misses a new lung nodule on the first slice of the CT abdomen and pelvis study. Which of the following best describes this type of miss?

1. Satisfaction of search
2. Framing bias
3. Availability bias
4. Edge of the film error*

• Edge of the film errors occur when an important finding is missed because it is at the edge of a study, such as in the periphery of an x-ray or on the top or bottom images of a CT of the abdomen and pelvis. This is a form of blind spot error.
• Satisfaction of search occurs when the visual search pattern is discontinued after identification of an abnormality that can explain the patient's symptom and the interpreting radiologist is "satisfied"that the diagnosis has been determined. No additional findings were described for this patient.
• Framing bias results from a tendency to be influenced by how a question is asked or how a problem is presented. This bias could lead the interpreting radiologist to misinterpret a finding, but not to miss the finding entirely.
• Availability bias refers to the tendency for diagnostic assessments to be unduly influenced by easily recalled experiences. This bias could lead the interpreting radiologist to misinterpret a finding, but not to miss the finding entirely.

Blind spots are areas where lesions are most commonly overlooked. Which of the following is considered a blind spot in abdominal CT imaging?

1. Liver capsule
2. Lung bases
3. Paraspinal region*
4. Ovaries

• The paraspinal region is a known blindspot in abdominal CT imaging, along with the subcutaneous tissue, peritoneal surface, and prostate gland. The remaining options have not been described or characterized as blind spots.