Incorporating a review of the scout and localizer images into the interpretive process will make detection of such abnormalities more likely. Even a cursory review of the hips on lumbar scout tomograms is occasionally high yield. Patients with back pain and spinal degenerative changes also frequently have hip pathology, some of which may be severe (Figure 2). The lumbar spine scout tomogram is particularly challenging because it usually provides an anteroposterior view of both hips. The lungs and posterior mediastinum also feature prominently in images of the thoracic spine. Similarly, a fracture (pathologic or otherwise) or other lesion of the humerus may be visible only on the scout tomogram.
Occasionally, lung pathology or mediastinal masses may be visible on the scout tomogram but not present on the cross-sectional CT images. 8,9 Scout images may demonstrate important pathology not included on the cross-sectional computed tomography (CT) or magnetic resonance images (MRI) (Figure 1).Ī typical scout tomogram/localizer for a cervical spine exam will often provide at least one view of a portion of the lungs, heart, clavicles, and humeri. 7 Radiologists have been sued for missing information on scout images that went unidentified on the initial interpretation. The Importance of Scout ImagesĪny interpretation of an imaging study should begin with a careful review of the scout or localizer images, which have been shown to include diagnostic information not included elsewhere in the imaging study. In this article, we provide guide to some common “blind spots” in spinal imaging. Occasionally, an extraspinal finding may be more serious than the original study indication, making detection even more important. 4-6 This is especially relevant to spine imaging, where differential diagnoses for perceived abnormalities tend to be less complex than those for brain imaging. 3 Multiple studies in radiology have also found that detection errors are more common than interpretive errors. For example, at least one study has shown that errors are more likely to be made in the last two hours of a long shift. 2 In addition, the sustained attention required for level-by-level-analysis of degenerative changes creates a unique environment for extraspinal findings to go undetected by a busy radiologist.Īnecdotally, the potential for diagnostic error is affected by several factors, including the complexity of the diagnostic imaging study, the presence of one or more abnormalities, the expertise of the interpreting physician, the number and type of interruptions, and even the timing of interpretation (early versus late into a work shift). 1 The most common reason for nontraumatic outpatient spine imaging remains osteoarthritis, which is more common in older patients.
Spine-imaging volumes are increasing, paralleling the rising number of aging Americans seeking care for back and neck pain.