Three-dimensional ultrastructural imaging and quantitative analysis of the periodontal ligament.
- 作者列表："Hirashima S","Kanazawa T","Ohta K","Nakamura KI
:The periodontal ligament (PDL) is a unique connective tissue mainly comprising collagen fiber bundles and cells between the roots of teeth and inner walls of the alveolar-bone socket. PDL fiber bundles are arrayed between teeth and bone, with both ends embedded in the cementum or alveolar bone as Sharpey's fiber. These bundles, synthesized by PDL fibroblasts (PDLFs), form several distinct groups within the PDL which has important functions besides tooth anchoring including tooth nutrition, proprioception, sensory detection, homoeostasis, and repair of damaged tissue. However, little is known about how the regular-PDL fiber bundle arrays are formed, maintained, and remodeled over large distances from cementum to alveolar bone. Recently, novel instruments and 3D-imaging methods have been developed that have been applied to the investigation of hard tissues including the PDL. Work from our laboratory has revealed the three-dimensional (3D) ultrastructure of PDLFs and PDL collagen bundles by focused ion beam/scanning electron microscope tomography. We have shown that PDLFs have a flat shape with long processes or a wing-like shape, while PDL bundles are a multiple-branched structure wrapped in thin sheets of PDLF cytoplasm. Furthermore, PDLFs form an extensive cellular network between the cementum and alveolar bone. The PDL cellular network is presumed to synchronize PDL fiber bundles and regulate arrays of PDL fiber bundles via gap junctions. In this review, we summarize and discuss our current 3D-histomorphometric studies of the PDL at the mesoscale level.
: 牙周膜 (PDL) 是一种独特的结缔组织，主要包括牙根和牙槽骨窝内壁之间的胶原纤维束和细胞。PDL纤维束排列在牙齿和骨之间，两端嵌入牙骨质或牙槽骨中，作为锐利纤维。由PDL成纤维细胞 (pdlf) 合成的这些束在PDL内形成几个不同的组，其除了牙齿锚定之外具有重要功能，包括牙齿营养、本体感觉、感觉检测、同源和受损组织的修复。然而，对于规则PDL纤维束阵列如何在从牙骨质到牙槽骨的大距离上形成、维持和重塑知之甚少。最近，已经开发了新的仪器和3d成像方法，其已经应用于包括PDL的硬组织的研究。我们实验室的工作通过聚焦离子束/扫描电子显微镜断层扫描揭示了PDLFs和PDL胶原束的三维 (3D) 超微结构。我们已经表明，PDLFs具有平坦的形状和长的突起或翼状形状，而PDL束是包裹在PDLF细胞质薄片中的多分支结构。此外，PDLFs在牙骨质和牙槽骨之间形成广泛的细胞网络。假定PDL蜂窝网络同步PDL纤维束并通过间隙连接调节PDL纤维束阵列。在这篇综述中，我们总结并讨论了我们目前在中尺度水平上PDL的三维组织形态计量学研究。
METHODS:OBJECTIVES:The aim was to evaluate the image quality and sensitivity to artifacts of compressed sensing (CS) acceleration technique, applied to 3D or breath-hold sequences in different clinical applications from brain to knee. METHODS:CS with an acceleration from 30 to 60% and conventional MRI sequences were performed in 10 different applications in 107 patients, leading to 120 comparisons. Readers were blinded to the technique for quantitative (contrast-to-noise ratio or functional measurements for cardiac cine) and qualitative (image quality, artifacts, diagnostic findings, and preference) image analyses. RESULTS:No statistically significant difference in image quality or artifacts was found for each sequence except for the cardiac cine CS for one of both readers and for the wrist 3D proton density (PD)-weighted CS sequence which showed less motion artifacts due to the reduced acquisition time. The contrast-to-noise ratio was lower for the elbow CS sequence but not statistically different in all other applications. Diagnostic findings were similar between conventional and CS sequence for all the comparisons except for four cases where motion artifacts corrupted either the conventional or the CS sequence. CONCLUSIONS:The evaluated CS sequences are ready to be used in clinical daily practice except for the elbow application which requires a lower acceleration. The CS factor should be tuned for each organ and sequence to obtain good image quality. It leads to 30% to 60% acceleration in the applications evaluated in this study which has a significant impact on clinical workflow. KEY POINTS:• Clinical implementation of compressed sensing (CS) reduced scan times of at least 30% with only minor penalty in image quality and no change in diagnostic findings. • The CS acceleration factor has to be tuned separately for each organ and sequence to guarantee similar image quality than conventional acquisition. • At least 30% and up to 60% acceleration is feasible in specific sequences in clinical routine.
METHODS:BACKGROUND:The main surgical techniques for spontaneous basal ganglia hemorrhage include stereotactic aspiration, endoscopic aspiration, and craniotomy. However, credible evidence is still needed to validate the effect of these techniques. OBJECTIVE:To explore the long-term outcomes of the three surgical techniques in the treatment of spontaneous basal ganglia hemorrhage. METHODS:Five hundred and sixteen patients with spontaneous basal ganglia hemorrhage who received stereotactic aspiration, endoscopic aspiration, or craniotomy were reviewed retrospectively. Six-month mortality and the modified Rankin Scale score were the primary and secondary outcomes, respectively. A multivariate logistic regression model was used to assess the effects of different surgical techniques on patient outcomes. RESULTS:For the entire cohort, the 6-month mortality in the endoscopic aspiration group was significantly lower than that in the stereotactic aspiration group (odds ratio (OR) 4.280, 95% CI 2.186 to 8.380); the 6-month mortality in the endoscopic aspiration group was lower than that in the craniotomy group, but the difference was not significant (OR=1.930, 95% CI 0.835 to 4.465). A further subgroup analysis was stratified by hematoma volume. The mortality in the endoscopic aspiration group was significantly lower than in the stereotactic aspiration group in the medium (≥40-<80 mL) (OR=2.438, 95% CI 1.101 to 5.402) and large hematoma subgroup (≥80 mL) (OR=66.532, 95% CI 6.345 to 697.675). Compared with the endoscopic aspiration group, a trend towards increased mortality was observed in the large hematoma subgroup of the craniotomy group (OR=8.721, 95% CI 0.933 to 81.551). CONCLUSION:Endoscopic aspiration can decrease the 6-month mortality of spontaneous basal ganglia hemorrhage, especially in patients with a hematoma volume ≥40 mL.
METHODS:OBJECTIVE:The primary purpose of this study was to evaluate the effectiveness of a three-dimensional (3D) software tool (smart planes) for displaying fetal brain planes, and the secondary purpose was to evaluate its accuracy in performing automatic measurements. MATERIAL AND METHODS:This prospective study included singleton fetuses with a gestational age (GA) greater than 18 weeks. Transabdominal two-dimensional ultrasound (2DUS) and 3D smart planes images were respectively used to obtain the basic planes of the fetal brain, with five parameters measured. The images, by either two-dimensional (2D) manual or 3D automatic operation, were reviewed by two experienced sonographers. The agreements between two measurements were analyzed. RESULTS:A total of 226 cases were included. The rates of successful detection by automatic display were as high as 80%. There was substantial agreement between the measurements of the biparietal diameter, head circumference and transcerebellar diameter, but poor agreement between the measurements of cisterna magna and lateral ventricle width. CONCLUSIONS:Smart Planes might be valuable for the rapid evaluation of fetal brain, because it simplifies the evaluation process. However, the technology requires improvement. In addition, this technology cannot replace the conventional manual US scans; it can only be used as an additional approach.