This paper proposes a novel density-based real-time segmentation algorithm,to extract ground point cloud in real time from point cloud data collected by roadside LiDAR.The algorithm solves the problems such as the lar...This paper proposes a novel density-based real-time segmentation algorithm,to extract ground point cloud in real time from point cloud data collected by roadside LiDAR.The algorithm solves the problems such as the large amount of original point cloud data collected by LiDAR,which leads to heavy computational burden in ground point search.First,point cloud data is filtered by straight-through filtering method and rasterized to improve the real-time performance of the algorithm.Then,the density of the point cloud in horizontal plane is calculated,and the threshold of the density is selected to extract the low-density regional point cloud according to the density statistical histogram and 95%loci.Finally,the low-density regional point cloud is used as the initial ground seeds for iterative optimization of ground parameters,and the ground point cloud is extracted by the fitted ground model to realize road point cloud extraction.The experimental results on 1055 frames of continuous data collected on real scenes show that the average time consumption of the proposed method is 0.11 s,and the average segmentation precision is 92.48%.This shows that the density-based road segmentation algorithm can reduce the time of point cloud traversal in the process of ground parameter fitting and improve the real-time performance of the algorithm while maintaining the accuracy of ground extraction.展开更多
To the Editor:Anti-melanoma differentiation-associated gene 5(MDA-S)positive interstitial lung disease(ILD)is featured by rapidly progressing respiratory failure and limited hospital survival.No standard therapy has b...To the Editor:Anti-melanoma differentiation-associated gene 5(MDA-S)positive interstitial lung disease(ILD)is featured by rapidly progressing respiratory failure and limited hospital survival.No standard therapy has been established or proven to be beneficial.Herein,we report a case of a rapidly progressing patient diagnosed of ILD with positive anti-MDA-5 antibody receiving tocilizumab treatment.展开更多
To the Editor:A 40-year-old Chinese woman who complained of chest pain and compression,dyspnea that lasted for 3 months,and abdominal distension that lasted for 2 weeks was admitted at our hospital in September 2015.I...To the Editor:A 40-year-old Chinese woman who complained of chest pain and compression,dyspnea that lasted for 3 months,and abdominal distension that lasted for 2 weeks was admitted at our hospital in September 2015.In early June 2015,she felt pain and compression behind the sternum after deep inspiration.Echocardiography showed mild pericardial effusion with normal left ventricular ejection fraction 63%.In July,these symptoms gradually worsened,while laboratory tests showed no abnormalities during routine blood examination,or in liver,kidney and thyroid functions.展开更多
To the Editor： The ＂Parotid Gland＂, out of all the salivary glands, is the one most frequently affected by neoplasms, accounting for approximately 75% in all cases. These neoplasms are generally benign, with only 2...To the Editor： The ＂Parotid Gland＂, out of all the salivary glands, is the one most frequently affected by neoplasms, accounting for approximately 75% in all cases. These neoplasms are generally benign, with only 25% of them being malignant forms.H The percentage of distant metastases from salivary gland is relatively low, with their occurrence being associated with high-grade tumors.展开更多
To the Editor:Adult granulosa cell tumor (AGCT)of the ovary is a low-grade malignant,sex cord-stromal tumor with an indolent course and late recurrence.Recurrences usually occur more than 5 years after the first treat...To the Editor:Adult granulosa cell tumor (AGCT)of the ovary is a low-grade malignant,sex cord-stromal tumor with an indolent course and late recurrence.Recurrences usually occur more than 5 years after the first treatment.[1] However,a few cases of aggressive AGCT have been reported.[2,3] We retrospectively reviewed all 213 AGCT patients at Peking Union Medical College Hospital between 2000 and 2018 and identified six Stage I cases with recurrence <5 years.The Ethics Committee of Peking Union Medical College Hospital specifically approved this study (No.S-K413),and all included patients provided written informed consent to participate in the study.展开更多
To the Editor:Tumor-induced osteomalacia(TIO)is an extremely rare paraneoplastic syndrome that is characterized by hypophosphatemia and hyperphosphaturia.[1]Since TIO was first described in 1947,more than 500 cases ha...To the Editor:Tumor-induced osteomalacia(TIO)is an extremely rare paraneoplastic syndrome that is characterized by hypophosphatemia and hyperphosphaturia.[1]Since TIO was first described in 1947,more than 500 cases have been reported worldwide.[2,3]TIO is an acquired hypophosphatemic osteomalacia caused by decreased phosphorus reabsorption in the renal tubules and increased renal phosphorus excretion.The clinical manifestations of TIO are diverse and non-specific;the most common presentations are progressive bone pain,fracture,skeletal deformity,and movement dysfunction.[1,2,3]To date,very few reported cases of TIO have presented with adjacent bone destruction caused by a phosphaturic mesenchymal tumor.Thus,clinicians lack knowledge and experience in prompt diagnosis and reasonable treatment of this rare condition.Herein,we present a case of TIO with substantial bone destruction that was successfully treated surgically[Figure 1].展开更多
To the Editor:Germ-cell tumors(GCTs)of the central nervous system(CNS),the morphologic,immunophenotypic,and(in some respects)genetic homologs of gonadal and other extraneuraxial germ-cell neoplasms,principally affect ...To the Editor:Germ-cell tumors(GCTs)of the central nervous system(CNS),the morphologic,immunophenotypic,and(in some respects)genetic homologs of gonadal and other extraneuraxial germ-cell neoplasms,principally affect children and adolescents.[1]The diagnosis of GCT of the CNS is not difficult,and the major GCT types are germinoma,teratoma,yolk sac tumor(YST),embryonal carcinoma,and choriocarcinoma.Neoplasms harboringmultiple types are calledmixed GCT(MGCT).Peak incidence of GCT of the CNS occurs in patients aged 10 to 14 years,and a clear majority of cases of all histologic types involve males.GCT of the CNS seems to be more prevalent in eastern Asia than in Europe and the United States.[1-5]In Japan,70%of patients withGCT of CNS aged 10 to 24 years and 73%were males,[6]but there were limited Chinese patients’large-scale data,only two studies reportedmore than 100 cases.[7,8]Were the types and clinical characteristics of GCTs in the CNS in Chinese patients consistent with Japan’s?We reviewed all cases of GCTs in the CNS diagnosed by pathology in Peking Union Medical College Hospital from year 1999 to 2019.We retrospectively collected and analyzed all cases underwent optical microscopy and immunohistochemical staining examinations,aiming to summarize and analyze the clinicopathologic features of them.展开更多
To the Editor： Pheochromocytomas are rare neuroendocrine tumors that originate from the chromaffin cells in the adrenal glands or associated sympathetic ganglia. To the best of our knowledge, malignant pheochromocyto...To the Editor： Pheochromocytomas are rare neuroendocrine tumors that originate from the chromaffin cells in the adrenal glands or associated sympathetic ganglia. To the best of our knowledge, malignant pheochromocytoma is extraordinarily rare, with a frequency of 0.2-0.9 case per 1,000,000 individuals per year, and there is obvious shortage of clinical reports on metastatic pheochromocytoma to the spine. Thus, it can be difficult to diagnose and may result in devastating consequences upon mismanagement.展开更多
基金supported by the National Key R&D Program of China(2021YFB3202200)S&T Program of Hebei(Nos.21340801D and 20310801D).
文摘This paper proposes a novel density-based real-time segmentation algorithm,to extract ground point cloud in real time from point cloud data collected by roadside LiDAR.The algorithm solves the problems such as the large amount of original point cloud data collected by LiDAR,which leads to heavy computational burden in ground point search.First,point cloud data is filtered by straight-through filtering method and rasterized to improve the real-time performance of the algorithm.Then,the density of the point cloud in horizontal plane is calculated,and the threshold of the density is selected to extract the low-density regional point cloud according to the density statistical histogram and 95%loci.Finally,the low-density regional point cloud is used as the initial ground seeds for iterative optimization of ground parameters,and the ground point cloud is extracted by the fitted ground model to realize road point cloud extraction.The experimental results on 1055 frames of continuous data collected on real scenes show that the average time consumption of the proposed method is 0.11 s,and the average segmentation precision is 92.48%.This shows that the density-based road segmentation algorithm can reduce the time of point cloud traversal in the process of ground parameter fitting and improve the real-time performance of the algorithm while maintaining the accuracy of ground extraction.
文摘To the Editor:Anti-melanoma differentiation-associated gene 5(MDA-S)positive interstitial lung disease(ILD)is featured by rapidly progressing respiratory failure and limited hospital survival.No standard therapy has been established or proven to be beneficial.Herein,we report a case of a rapidly progressing patient diagnosed of ILD with positive anti-MDA-5 antibody receiving tocilizumab treatment.
文摘To the Editor:A 40-year-old Chinese woman who complained of chest pain and compression,dyspnea that lasted for 3 months,and abdominal distension that lasted for 2 weeks was admitted at our hospital in September 2015.In early June 2015,she felt pain and compression behind the sternum after deep inspiration.Echocardiography showed mild pericardial effusion with normal left ventricular ejection fraction 63%.In July,these symptoms gradually worsened,while laboratory tests showed no abnormalities during routine blood examination,or in liver,kidney and thyroid functions.
文摘To the Editor： The ＂Parotid Gland＂, out of all the salivary glands, is the one most frequently affected by neoplasms, accounting for approximately 75% in all cases. These neoplasms are generally benign, with only 25% of them being malignant forms.H The percentage of distant metastases from salivary gland is relatively low, with their occurrence being associated with high-grade tumors.
文摘To the Editor:Adult granulosa cell tumor (AGCT)of the ovary is a low-grade malignant,sex cord-stromal tumor with an indolent course and late recurrence.Recurrences usually occur more than 5 years after the first treatment.[1] However,a few cases of aggressive AGCT have been reported.[2,3] We retrospectively reviewed all 213 AGCT patients at Peking Union Medical College Hospital between 2000 and 2018 and identified six Stage I cases with recurrence <5 years.The Ethics Committee of Peking Union Medical College Hospital specifically approved this study (No.S-K413),and all included patients provided written informed consent to participate in the study.
文摘To the Editor:Tumor-induced osteomalacia(TIO)is an extremely rare paraneoplastic syndrome that is characterized by hypophosphatemia and hyperphosphaturia.[1]Since TIO was first described in 1947,more than 500 cases have been reported worldwide.[2,3]TIO is an acquired hypophosphatemic osteomalacia caused by decreased phosphorus reabsorption in the renal tubules and increased renal phosphorus excretion.The clinical manifestations of TIO are diverse and non-specific;the most common presentations are progressive bone pain,fracture,skeletal deformity,and movement dysfunction.[1,2,3]To date,very few reported cases of TIO have presented with adjacent bone destruction caused by a phosphaturic mesenchymal tumor.Thus,clinicians lack knowledge and experience in prompt diagnosis and reasonable treatment of this rare condition.Herein,we present a case of TIO with substantial bone destruction that was successfully treated surgically[Figure 1].
文摘To the Editor:Germ-cell tumors(GCTs)of the central nervous system(CNS),the morphologic,immunophenotypic,and(in some respects)genetic homologs of gonadal and other extraneuraxial germ-cell neoplasms,principally affect children and adolescents.[1]The diagnosis of GCT of the CNS is not difficult,and the major GCT types are germinoma,teratoma,yolk sac tumor(YST),embryonal carcinoma,and choriocarcinoma.Neoplasms harboringmultiple types are calledmixed GCT(MGCT).Peak incidence of GCT of the CNS occurs in patients aged 10 to 14 years,and a clear majority of cases of all histologic types involve males.GCT of the CNS seems to be more prevalent in eastern Asia than in Europe and the United States.[1-5]In Japan,70%of patients withGCT of CNS aged 10 to 24 years and 73%were males,[6]but there were limited Chinese patients’large-scale data,only two studies reportedmore than 100 cases.[7,8]Were the types and clinical characteristics of GCTs in the CNS in Chinese patients consistent with Japan’s?We reviewed all cases of GCTs in the CNS diagnosed by pathology in Peking Union Medical College Hospital from year 1999 to 2019.We retrospectively collected and analyzed all cases underwent optical microscopy and immunohistochemical staining examinations,aiming to summarize and analyze the clinicopathologic features of them.
文摘To the Editor： Pheochromocytomas are rare neuroendocrine tumors that originate from the chromaffin cells in the adrenal glands or associated sympathetic ganglia. To the best of our knowledge, malignant pheochromocytoma is extraordinarily rare, with a frequency of 0.2-0.9 case per 1,000,000 individuals per year, and there is obvious shortage of clinical reports on metastatic pheochromocytoma to the spine. Thus, it can be difficult to diagnose and may result in devastating consequences upon mismanagement.
