Use of 18 F-sodium fluoride bone PET for disability evaluation in ankle trauma: A pilot study

Abstract

Background: There are no objective and accurate rating tools for permanent impairment of traumatized ankles. The purpose of this study is to assess the role of 18F-Sodium fluoride (18F-NaF) positron emission tomography-computed tomography (PET/CT) bone scans in evaluating patients with limited ankle range of motion (ROM) after trauma. Methods: 18F-NaF PET/CT was performed in 121 patients (75 men, 46 women; mean age: 45.8) who had ROM <70% of normal after trauma affecting ankles. Metabolic target volume (MTV), the sum of voxels with standardized uptake value (SUV) >2.5 was automatically obtained from the 3D volume that included the ankle joint. The maximum & mean SUV (SUVmax & SUVmean), and the total lesion activity (TLA) were measured. Results: The median period from injury to performing 18F-NaF PET/CT was 290days. The causes of injury were as follows: fracture (N=95), Achilles tendon rupture (N=12), and ligament injury (N=12). Hot uptake in the ankle was seen in 113 of 121 patients. The fracture group had higher SUVmax, SUVmean, and TLA values than the non-fracture group. More limited ROM correlated with higher hot-uptake parameters (SUVmax, SUVmean, TLA). In subgroup analysis, the same correlations were present in the fracture, but not in the non-fracture group. Conclusions: 18F-NaF PET/CT can provide considerable information in impairment evaluations of limited ankle ROM, particularly in fracture around the ankle. Thus, 18F-NaF bone PET/CT may provide an additional option as an objective imaging tool in disability assessment after ankle injury.