False-negative triple-phase bone scans in spinal cord injury to detect clinically suspect heterotopic ossification: a case series.

BACKGROUND/OBJECTIVE: Heterotopic ossification (HO) is a complication seen in patients after spinal cord injury (SCI). Triple-phase nuclear bone scanning is the most sensitive test for the detection of HO. This retrospective study assesses whether patients with clinically suspected HO but negative triple-phase nuclear bone scans develop delayed positive nuclear bone scans.

CASE SERIES: A cohort of patients with SCI and clinically suspected HO who underwent triple phase nuclear bone scans over a period of 2 years was identified from retrospective chart review of an acute inpatient SCI rehabilitation service. A subgroup of 7 patients with initially negative but subsequently positive triple-phase nuclear bone scans was identified, and the following data were collected: date, mechanism, admission level, and admission completeness of injury as well as date, number, and results of bone scans. Laboratory studies were also collected during the time of imaging.

RESULTS: Over a 2-year period, 343 patients were admitted to the SCI rehabilitation service; 60 patients were suspected of having HO and underwent a total of 85 triple-phase nuclear bone scans. Seven patients were identified with initially negative but subsequently positive bone scans.

CONCLUSIONS: In patients with clinically suspicious HO but negative bone scans, follow-up scans are indicated to identify initial false-negative studies.