Visualization of discrete sacral foramina as an ancillary sign of superscan

the purpose of this study was to determine if visualization of discrete sacral foramina on bone scintigraphy can be used as an adjunct criterion supportive of a superscan diagnosis.

the Radiology Information System at our institution was queried for all bone scintigraphy reports, during July 1999 to July 2009, containing the words/phrases: normal bone scan, normal bone scintigraphy, superscan, or diffuse osseous metastatic disease. The final study group consisted of 22 normal studies and 8 superscans. All studies were reviewed by 2 nuclear medicine physicians who rated the examinations on a numeric scale of bone-to-soft tissue activity, whether they would classify the study as a superscan (based on previously published criteria), whether sacral foramina were visualized, and, if so, how many?

of the 22 normal studies, no distinct sacral foramen was visualized in 17 cases. Of the 8 superscan patients, 1 patient demonstrated 8 foramina, 4 patients demonstrated 4 foramina, 1 patient demonstrated 3 foramina, and 2 patients demonstrated none. There was a statistically significant difference between the normal and superscan groups (P < 0.0017). Based on statistical analysis, it was determined that visualizing at least 3 distinct sacral foramina could be used as an ancillary finding to support the diagnosis of superscan.

the ability to clearly visualize at least 3 sacral foramina is a statistically significant finding that may be useful as an ancillary criterion to differentiate normal bone scintigraphy from a superscan.