Chapter 2: RADIOLOGIC EVALUATION, SEARCH PATTERNS, AND DIAGNOSIS

Where Does Radiologic Image Interpretation Begin?^1–20

Radiologic image interpretation requires foundations in imaging technology, dimensional perceptions of anatomy, characteristic patterns of pathology, and an organized method of visually searching the image for abnormalities. A search pattern describes such a methodology.

Learning a tried-and-true search pattern is a good place to start looking at images in a meaningful manner. But it is wise to be a cautious learner. Strict application of an established search pattern might appear to the novice to make diagnosis easy. There are times when diagnosis is easy—a dislocated joint or a fractured bone is plain for anyone to see. Often, however, the normal anatomic variants, complexity of multiple diagnoses, deviations in disease presentation, and insignificant findings that later prove significant (or the opposite) can make interpretation exceedingly difficult.

What Are the Pitfalls of Image Interpretation?

Errors! Errors in radiographic interpretation have been researched for over 50 years and continue to be studied in an effort to understand and minimize sources of error.^1,2 Errors can be classified as errors of observation or errors of interpretation.¹⁴ Errors of observation can be linked to incomplete or faulty search patterns. Errors in interpretation can be linked to the practitioner's failure to link abnormal radiologic signs to relevant clinical data.

Be aware, however, that errors in reading images are inevitable and should not be confused with carelessness on the part of the reader.^15,16 Rather, errors are a consequence of the physiological process of perception, an unavoidable hazard of the human condition. And despite 21st-century advancements, technology has not solved the problem of perceptual error but only displaced it to newer technologies. Attempts to identify factors that contribute to or reduce errors in reading images are ongoing. One factor known to reduce error is communication between the clinician and radiologist.

What Can the Nonradiologist Offer to Image Interpretation?

The nonradiologist can offer expertise from her or his own area of clinical specialty and collaborate with the radiologist and others involved in the patient's care to effect a positive patient outcome. An example of this is seen in the military's use of physical therapists as primary musculoskeletal screeners. A 1973 study of over 2,117 patients presenting with low back pain and screened by physical therapists demonstrated a decrease in radiologic examination by over 50%.²¹ These physical therapists had sufficient additional training in basic radiology to assist them in discriminating which differential musculoskeletal diagnoses needed to be defined by radiology and which ones were inconsequential to radiologic examination. The significant factor was the physical therapist's specialty in musculoskeletal physical examination.

Where does radiologic interpretation begin for the nonradiologist? Chapter 1 covered fundamentals of x-ray technology and the perception of three-dimensional anatomy on a two-dimensional image. This chapter covers the fundamentals of ...