Usefulness of Bone SPECT/CT for Predicting Avascular Necrosis of the Femoral Head in Children with Slipped Capital Femoral Epiphysis or Femoral Neck Fracture

Abstract

Objective This study aimed to investigate the usefulness of bone single-positron emission tomography/computed tomography (SPECT/CT) of the hip in predicting the later occurrence of avascular necrosis (AVN) after slipped capital femoral epiphysis (SCFE) or femoral neck fracture in pediatric patients. The quantitative parameters of SPECT/CT useful in predicting AVN were identified. Materials and Methods Twenty-one (male:female, 10:11) consecutive patients aged < 18 years (mean age ± standard deviation [SD], 11.0 ± 2.7 years) who underwent surgery for SCFE or femoral neck fracture and postoperative bone SPECT/CT were included. The maximum standardized uptake value (SUV), mean SUV, and minimum SUV of the femoral head were measured. The ratios of the maximum SUV, mean SUV, and minimum SUV of the affected femoral head to the contralateral side were determined. Patients were followed up for > 1 year after the surgery. The SPECT/CT parameters were compared between patients who developed AVN and those who did not. The accuracy of SPECT/CT parameters for predicting AVN was assessed. Results Six patients developed AVN. There was a significant difference in the ratio of the mean SUV among patients who developed AVN (mean ± SD, 0.8 ± 0.3) and those who did not (1.1 ± 0.2, p = 0.018). However, there were no significant differences in the ratios of the maximum and minimum SUV between the groups (all p = 0.205). For the maximum, mean, and minimum SUVs, no significant differences were observed between the groups ( p = 0.519, 0.733, and 0.470, respectively). The cutoff mean SUV ratio of 0.87 yielded a 66.7% sensitivity and 93.2% specificity for predicting AVN. Conclusion Quantitative bone SPECT/CT is useful for evaluating femoral head viability in pediatric patients with SCFE or femoral neck fractures. Clinicians should consider the high possibility of later AVN development in patients with a decreased mean SUV ratio.

Methods to predict osteonecrosis of femoral head after femoral neck fracture: a systematic review of the literature

“…Preoperative quantitative indicators included a percentage of photon defect [ 41 ], head-to-head uptake ratio or head-to-acetabulum uptake ratio [ 42 ], and the ratio of radionuclide uptake of the affected fractured femoral head to the healthy contralateral femoral head (F/N) [ 43 , 44 ]. Postoperative quantitative indicators include the mean standardized uptake value of the femoral head (SUV) [ 45 , 46 ]. Park et al [ 41 ] concluded that the percentage of photon defect in the femoral head was a useful index to determine the surgical methods for FNFs, considering hip replacement when the photon defect was greater than 15%, and internal fixation if the photon defect was less than 15%.…”

“…Yuan et al [ 43 ] recommended hip replacement when F/N was less than or equal to 0.5 and suggested hollow screw fixation was a more appropriate treatment if F/N ratio is greater than 0.5. Song et al [ 45 ] concluded that patients with a lower mean SUV ratio were highly likely to develop femoral head necrosis in the future.…”

“…After comprehensive consideration, we recommend selecting dynamic enhanced MRI or SPECT/CT in combination with the intraoperative prediction of bleeding from the holes of proximal cannulated screws to predict ONFH after FNF. Both dynamic enhanced MRI and SPECT/CT can qualitatively and quantitatively evaluate femoral head perfusion in patients with FNF, which have a high sensitivity and specificity [ 41 – 45 , 62 – 65 ]. However, dynamic enhanced MRI and SPECT/CT could not be performed in an emergency case, or on weekends.…”