| Objective: The aim of this study was to evaluate the value of a morphological contour interpolation(MCI)based semiautomatic segmentation in radiologic examination of guided bone regeneration(GBR).In vitro specimens were established to evaluate the accuracy of this new segmentation method in volume measurement and 3D reconstruction.And the operation time was counted to analyze its clinical application efficiency.The MCI-based segmentation method was used to evaluate grafted bone alterations following guided bone regeneration according to cone beam computed tomography(CBCT)data.The volumes of grafted bone were quantified and radiological outcome of two different collagen membranes was compared.Methods: 1.In vitro specimens simulating clinical GBR and simultaneous implant placement were established.Specimens filled with bone grafts were taken CBCT scan.The 3D reconstruction structure was obtained through the MCI-based semiautomatic segmentation method and manual segmentation method,measuring bone volume,and analysis of the accuracy of 3D reconstruction structure,statistics of two kinds of method measuring the time required,to evaluate the clinical application of new type of semi-automatic segmentation method efficiency.2.The data were retrieved from an ongoing randomized controlled trial.Patients were randomly allocated into two groups: 1)control group(CG): Bio-Gide 2)test group(TG): bovine dermis-derived collagen membrane.CBCT examinations were performed 1 week(T0)and 6 months after surgery(T1).PES/WES at T1,grafted bone volume and density changes from T0 to T1 were recorded.Results: 1.The accuracy of MCI-based segmentation method was very high with differences between test and control measurements never exceeding 7.5%.The reproducibility of the measurements showed very low coefficients of variation below 1.2%,indicating excellent reproducibility.In addition,compared with the conventional manual segmentation method,the MCI-based segmentation method can significantly reduce the measurement time and the 3D reconstruction structure of the interest area was close to the actual structure.2.Thirty-six patients(16/20 in test/control group,respectively)were enrolled in the present study.Excellent inter-observer reliability(ICC≥0.97)was revealed for repeated measurements using this method.Significant volumetric reduction of grafted bone were found in both groups(test group: from 0.60 to 0.39 cm3,P<0.01;control group: from 0.54 to 0.31 cm3,P<0.01).Mean bone density(grayscale values)significantly increased from 305.12 to 456.69 in CG(P<0.01).In TG,it slightly increased from 304.75 to 393.27(P=0.25).The mean PES/WES values were 13.84(6.62/7.22)and 13.90(6.70/7.20)for TG and CG,respectively.As for inter-group comparison,no significant differences of grafted bone volume change,density change and PES/WES were found between two groups.Conclusions: 1.The tested MCI-based segmentation method used in CBCT data showed excellent accuracy and high reproducibility for measuring volume of bone grafts specimens imitating GBR procedure.Therefore,the MCI-based method can be applied to the radiologic volume measurement after GBR procedure.2.Within the limitations of this study,the novel MCI based semi-automated segmentation protocol is a reproducible tool to segment and visualize changes of grafted bone in 3D.The clinical application of this method allows a promising full 3D follow-up of bone grafts morphology after GBR procedures.Furthermore,both two collagen membranes could be used as a barrier membrane for GBR in humans. |
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