Recognition performance and perceived quality of video enhanced for the visually impaired

Subjects with central field loss (CFL) individually selected enhancement parameters to improve visibility of static video images. The effect of enhancement on performance and on perceived quality of motion video was assessed. Performance, e.g. recognition of visual details, was assessed by having subjects answer questions regarding visual information contained in the video motion segments that were enhanced using the individually-selected parameters. Enhancement did not improve subject performance on questions about video content. This result might be due to a ceiling effect limitation of the performance assessment method. In a second procedure, subjects' continuous perceptions of quality (using an adjective-based rating scale) were made while the enhancement parameters were abruptly switched among multiple values; these included the individually-selected enhancements, as well as unenhanced, over-enhanced, and degraded segments. The results indicate that adaptive enhancement (individually-tuned using a static image) adds significantly to perceived image quality when viewing motion video. Subjects who selected stronger contrast enhancement also perceived the enhancement to provide a larger benefit in image quality.     

Two-level posterior lumbar interbody fusion for degenerative disc disease: improved clinical outcome with restoration of lumbar lordosis

BACKGROUND CONTEXT: Although posterior lumbar interbody fusion (PLIF) for degenerative lumbar diseases is routine, there are few reports on double-level PLIF. PURPOSE: To evaluate the clinical outcomes of double-level PLIF. STUDY DESIGN/SETTING: A retrospective study of operated cases in Gifu, Japan. PATIENT SAMPLE: Nineteen patients (8 men and 11 women, 59.5+/-10.2 years) who underwent double-level PLIF between 1996 and 2001. OUTCOME MEASURES: Operation time, blood loss, complications, the Japanese Orthopaedic Association (JOA) score for back pain and lumbar sagittal alignment were evaluated. METHODS: Patients were examined retrospectively at follow-ups of 3.6+/-1.7 years. Primary diseases were spondylolisthesis, spinal canal stenosis, degenerative scoliosis and herniated intervertebral disc. Fusion areas were L3 to L5 in 15 cases and L4 to S1 in 4 cases. RESULTS: The mean JOA score increased from an initial score of 12.9+/-3.5 to 21.3+/-4.9 at the final follow-up. There was a positive correlation (R=0.718, p<.001) between the increase in lordotic angle and the increase in the JOA score. Several parameters suggested that the surgical invasiveness was not minimal. CONCLUSION: Double-level PLIF provided satisfactory results and preserved lumbar spine lordosis.     

Cervifix在陈旧性寰枢椎脱位并高位颈髓压迫症中的应用

目的:探讨Cervifix内固定系统治疗陈旧性寰枢椎脱位并脊髓不全损伤的价值。方法:36例陈旧性寰枢椎脱位并脊髓不全损伤行后路融合、Cervifix内固定。男23例、女13例,年龄15～62岁,平均38.3岁。陈旧性外伤21例,先天性畸形9例,类风湿性关节炎伴寰椎前脱位6例。结果:随访8～42个月,平均19个月。术后脊髓功能按JOA17分法评定,改善率为71.4％。全部患者均获骨性融合,内置物无松动、断裂及脊髓损伤加重等并发症。结论:Cervifix内固定可提供坚强有效的节段性固定,提高融合率。同时,可预防单纯减压融合术后早期失稳导致的高位脊髓损伤加重。     

中下段颈椎的应力松弛特性及前、后路手术对其的影响

目的 研究中下段颈椎的应力松弛特性，并评估椎间盘切除植骨术与椎板切开术对其影响。方法 6例新鲜尸体完整颈椎及手术后颈椎，在模拟生理状态下进行屈曲及伸展位的应力松弛实验。结果 在恒应变条件下，绘制术前及不同术式后的中下段颈椎的应力松弛函数及曲线；术后的中下段颈椎的应力和初始化应力比值G(t)比术前明显增大，前路椎间盘切除植骨术后的G(t)值比椎板切开术大，两者均有统计学意义。结论 在恒应变条件下，颈椎具有快速应力松弛敏感性，屈曲位比伸展位大。椎板成形术及颈椎前路椎间盘切除植骨术都使颈椎的应力松弛能力减弱，前路椎间盘切除植骨术的影响更大。     

维纳滤波器在数字化X射线影像中的应用

介绍了一种简单有效的维纳滤波器设计过程,并采用该过程对数字化X射线影像进行滤波,试验表明:维纳滤波器能在去除图像噪声的同时较好地保留图像细节,具有实际应用价值。     

生理影像信息技术及其临床应用

生理影像是功能性医学影像的一个重要分支,也是临床医学工程的一个极其重要的研究和应用领域。多年来,作者及其研究生与临床医务人员相结合,在电生理影像和热生理影像的信息获取和数字化处理技术方面进行了大量及深入的研究,提出了一种体内热估计(ITE)新技术。本文重点介绍热生理影像信息在妇女乳腺癌诊断中的应用。通过对约五千例妇女乳腺病筛选的结果,表明了生理影像信息处理及ITE技术在临床医学上的应用价值。     

颈部淋巴结超声特征的计算机提取及相关性评价

目的：评价计算机所提取的颈部淋巴结超声特征与医生的经验判断的相关性，以预测能否实现颈部淋巴结超声图像计算机辅助诊断。材料和方法：利用彩色多普勒超声观察43例患者的106个淋巴结的超声特征，包括大小、形态、边界、纵横比、淋巴门、皮髓质分布及比例、淋巴结内部回声、血流分布等。将超声医生判断分级的结果与计算机提取的淋巴结超声特征的参数定量结果作相关分析。结果：相关性较好的参数为NRL过零率（r=0．304，P=0．002）、凸包深度（r=0．32，P=0．001）、长／短径比率（r=-0．318，P=0．001）、血流像素点数（r=0．702，P〈0．001）、投影轮廓点分布的熵（r=0．719，P〈0．001）。结论：通过对颈部淋巴结超声图像提取量化特征参数，初步实现了颈部淋巴结良、恶性疾病的计算机辅助诊断。     

颈椎病合并下颈椎不稳的外科治疗策略

目的 探讨颈椎病合并下颈椎不稳的临床诊断、术式选择及手术疗效。方法 对手术治疗的32例颈椎病合并下颈椎不稳，分别摄术前及术后随访之颈椎正侧位、伸屈侧位X线片及颈椎MR检查。32例均经前路行减压、植骨融合、内固定手术治疗。以颈椎不稳节段与颈椎主要退变节段重合，并行减压内固定患者为A组，共7例；对25例颈椎不稳与颈椎病节段不重合，以其中仅处理颈椎病节段9例为B组；在处理颈椎病节段同时处理颈椎不稳节段16例为C组。以“40分”评分法分别对患者术前、术后随访情况予以评价，对数据分别行组间均值t检验及组内配对t检验。结果 经12～36个月随访（平均25个月），所有患者均获骨性融合，平均改善率61．2％。A、B、C组间均值t检验：术前差异无显著性（P〉0．05）、术后差异亦无显著性（P〉0．05）。各组内配对t检验，术前、术后随访差异均有显著性（P〈0．05）。结论 在颈椎病合并下颈椎不稳的患者中，不稳节段与主要退变节段关系密切但往往并不重合。通过颈前路手术，在处理颈椎病节段同时处理相邻颈椎不稳节段，临床疗效满意。     

后外侧融合对胸腰椎爆裂型骨折疗效的影响

目的 观察后外侧融合对预防胸腰椎爆裂型骨折短节段固定失败的作用及意义。方法 本组60例胸腰椎爆裂型骨折患者，A组30例均为我院收治患者，B组30例均为外院手术来我院复查的患者。A组行短节段内固定自体髂骨植骨、后外侧融合术；B组仅行短节段内固定，未植骨融合。平均随访16个月，在X线侧位片上测量Cobb角、伤椎后凸角及矢状面指数（SI），临床疗效评价采用下腰痛评分法（low back outcome score，LBOS）。结果 手术前、后两组间Cobb角、伤椎后凸角、SI比较，差异无统计学意义（P〉0．05），而末次随访时两组间Cobb角、伤椎后凸角、SI比较，差异有统计学意义（P〈0．01）。LBOS评分A组的优良率为73％（22／30），B组仅为43％（13／30）。结论 后外侧融合是降低内固定失败、减少纠正丢失等并发症的有效措施，只行内固定而不做植骨融合明显增高了并发症的发生率，是不恰当的手术方式。