Can Pixel Value Ratio be Used in the Assessment of Ceramic Bone Substitute Incorporation? Observations from a Pilot Study

Abstract

SummaryBackgroundAssessment of bone graft substitute incorporation is critical in the clinical decision making process and requires special investigations. We examined if the pixel value ratio (PVR) obtained in routine follow-up digital radiographs could be used for such assessment.Material/MethodsRadiographic images were acquired using either computed radiography or flat panel digital radiography systems. The PVR from radiographs of thirty children with ceramic bone substitute grafting were analyzed using the software from the picture archival and communication system (PACS) workstation. Graft incorporation was also assessed using the van Hemert scale. Three independent observers (A, B, C) measured PVRs at two different time points during the first and the last follow-up visits. PVR was compared with the van Hemert scale scores and analyzed using Spearman’s rank correlation.ResultsThe mean intra-observer reliability was 0.8996, and inter-observer reliabilities were 0.69 (A vs. C), 0.78 (A vs. B), and 0.85 (B vs. C) for the first follow-up visit and 0.74 (A vs. C), 0.82 (A vs. B), and 0.70 (B vs. C) for the last follow-up measurements. Spearman’s correlation showed a strong negative association between PVR values and van Hemert scale scores, as the healing process advanced on serial measurements at each follow-up (r=–0.94, n=60, z=–7.24, p≤0.0001). The reliability of the PVR measurements was assessed using an aluminum step wedge and ceramic graft.ConclusionsPVR is potentially a reliable indicator of bone graft incorporation and can aid in clinical decision making provided standard radiographic techniques are used.

A study to evaluate the extent of bone healing in mandibular distraction osteogenesis using preoperative and postoperative pixel value ratio

“…Bafor [12] conducted a statistical study of PVR in 42 patients who underwent lower limb lengthening and concluded that PVR is a rapid and reliable evaluation metric to objectively assess the healing status of regenerated bone and bone maturity during distraction. Balakumar et al [13] found that PVR may be a reliable indicator of bone graft fusion to aid clinical decision by measuring and analyzing PVR of bone grafts in 30 patients. Some studies have shown gender differences in adults, and Liu et al [1] studied the gender of long bone lengthening and found no signi cant difference which is consistent with our study, and there was no difference in PVR between the genders of children.…”

A Retrospective Study of Postoperative Development of Implant-Induced Osteoporosis in Radial–Ulnar Fractures in Toy Breed Dogs Treated with Plate Fixation

“…Studies on bone formation and fracture healing that evaluated PV and the PVR found that bone formation was correlated with PV on digital radiographs. 12,13,17,18 Although this study was performed as a multi-hospital case study, PVR was used as a measure of bone mineral areal density because measured data had been normalized to the values recorded on the humeral condyle at each time point. Since IIO involves decreased bone mineral density in the cortical bone beneath the plate, we defined IIO as a decrease in the PVR.…”