Incidental abdominopelvic findings on expanded field-of-view lumbar spinal MRI: Frequency, clinical importance, and concordance in interpretation by neuroimaging and body imaging radiologists

AIM: To characterize the frequency of identification, clinical importance, and concordance in interpretation of incidental abdominopelvic findings identified on routine lumbar spinal MRI using supplemental expanded field-of-view (FOV) coronal imaging. MATERIALS AND METHODS: All lumbar spinal MRI reports over a 12-month period were retrospectively reviewed for the presence of incidental abdominopelvic findings identified using expanded FOV coronal imaging. Medical records were used to identify those findings that received follow-up, which were then categorized according to final diagnosis and classified as "indeterminate," "likely clinically unimportant," and "likely clinically important". All cases that received follow-up were blindly and independently re-reviewed by a neuroimaging radiologist and body-imaging radiologist, and reviewer performances were compared to assess for agreement with regard to lesion significance, need for follow-up, and other parameters. RESULTS: In total, 2067 reports were reviewed: 687 (33.2%) featured one or more incidental abdominopelvic findings, and 102 (4.9%) findings received further evaluation. Of these, 11 (10.9%) were classified as "indeterminate," 50 (49%) as "likely clinically unimportant," and 41 (40.1%) were classified as "likely clinically important." Excellent agreement was observed between the reviewing radiologists for all evaluated parameters. CONCLUSION: The addition of an expanded FOV coronal sequence to the standard lumbar spinal MRI protocol was associated with the identification of a large number of incidental abdominopelvic findings, the minority of which represent likely clinically important findings. Most incidental findings were confidently dismissed by a neuroimaging radiologist as likely clinically unimportant without utilization of additional clinical or radiographic resources.