ABSTRACT
OBJECTIVE: To develop a new threshold segmentation method for mandible image segmentation. METHODS: CT data of 12 volunteers were exported into Mimics 10. 01. An improved method usinga narrowed threshold range (the maximum threshold range that can segment mandible without manual efforts) was developed in 3D reconstruction, and compared with the traditional method. We used dilation operations to make up the information loss of image borders, by which we obtained an approxinate segment result. A precise segment resultwas eventually arrived with the help of logical operations and region growing. We compared mean time consumptions of the two methods, as well as their 3D reconstruction results using Geomagic Studio 11. 0. RESULTS: The new method generated a success rate of 91. 67% (11/12), with a mean time consumption of (319. 7±125. 3) s. The traditional method took much longer time [(1,261. 3±427. 3) s, P<0. 05] than the new method. Compared with the reconstruction results of traditional method, the new method had an outward deviation of (0. 066±0. 011) mm and an inward deviation of (0. 070±0. 008) mm. Such deviations were less than the minimum distance that a naked eye can discern. The lower limit of the widest threshold range which mandible could be isolated was (507. 72± 100. 31) HU, while the upper limit was (1,133. 33±47. 57) HU. CONCLUSION: The new method we proposed can improve the efficiency of threshold segmentation of mandible.
Subject(s)
Algorithms , Imaging, Three-Dimensional , Mandible/anatomy & histology , Tomography, X-Ray Computed , HumansABSTRACT
BACKGROUND: The purpose of this meta-analysis was to find out whether the proximal femoral nail was better than the dynamic hip screw in the treatment of trochanteric fractures with respect to operation time, blood transfusion, hospital stay, wound complications, number of reoperation, and mortality rate. METHODS: All randomized controlled trials comparing proximal femoral nail and dynamic hip screw in the treatment of trochanteric fractures were included. Articles and conference data were extracted by two authors independently. Data was analyzed using RevMan 5.1 version. Eight trials involving 1348 fractures were retrieved. RESULTS: Compared with DHS fixation, PFN fixation had similar operation time (95% CI: -15.28-2.40, P = 0.15). Blood loss and transfusion during perioperative time were also comparable between the two fixations (95% CI: -301.39-28.11, P = 0.10; 95% CI: -356.02-107.20, P = 0.29, resp.). Outcomes of hospital stay (95% CI: -0.62-1.01, P = 0.64), wound complication (95% CI: 0.66-1.67, P = 0.82), mortality (95% CI: 0.83-1.30, P = 0.72), and reoperation (95% CI: 0.61-1.54, P = 0.90) were all similar between the two groups. CONCLUSION: PFN fixation shows the same effectiveness as DHS fixation in the parameters measured.
