应用ROC曲线评价DR后处理技术对胸部影像的影响

目的:运用ROC曲线,探讨DR胸部摄影最佳的影像后处理技术。方法:使用DR系统设置的正常胸部摄影条件,对胸部体模与专用于X线摄影的ROC曲线评价体模(TRG)进行组合并曝光。分析未使用后处理技术及使用不同后处理技术,对DR胸部摄影胸片影像的影响。结果:使用单纯噪声消除技术、噪声消除加图像反转及噪声消除加全屏放大三种后处理技术所得的ROC曲线下面积Az值依次为0.85、0.825及0.925,均明显大于未使用后处理技术的面积Az值0.6;单纯噪声消除技术获得的ROC曲线下面积略大于噪声消除加图像反转技术的面积;噪声消除加全屏放大技术获得的ROC曲线下面积Az值最大。结论:应对胸部原始影像实施后处理调节。单纯噪声消除技术可明显增加影像的信息量,若在噪声消除基础上实施全屏放大技术,可获得DR胸部摄影的最大影像信息量。     

飞利浦DR图像处理计算机工作原理及软件安装

目的:为减少飞利浦DR图像处理计算机停机时间,排除飞利浦DR图像处理计算机的软件故障.方法:通过介绍飞利浦DR图像处理计算机的硬件结构及工作原理,详细描述图像处理流程,讲解软件安装和校准方法,解决安装过程中所遇到的各种问题.结果:通过优化后的安装方法,可以快速排除软件故障.结论:医院医疗仪器维修工程师通过研究技术资料,不断总结经验,可以对大型医疗设备进行维修     

X线平片与多层螺旋CT在四肢骨关节骨折中的诊断价值

目的探讨X线平片与多层螺旋CT(MSCT)后处理技术在诊断四肢骨关节骨折中的应用价值。方法回顾性分析我院就诊治疗的62例四肢骨关节骨折患者的临床资料进行回顾性整理分析,以手术诊断为标准,总结不同检查方法对四肢骨关节骨折的诊断正确性,分析不同骨关节骨折在不同影像学检查中的图像特征。结果整理临床病例资料可知,X线平片和MSCT后技术处理检查对四肢骨关节骨折检出率分别为83.87%和96.77%,比较差异间无统计学意义(P>0.05),但MSCT后技术处理对四肢骨关节骨折的诊断符合率显著高于X线平片检查,比较差异间具有统计学意义(P<0.05);由资料可知,经X线平片检查符合诊断48例,其余14例显示为可疑及未见异常但是实际上存在着隐匿性骨折,而X线检查中,多数均表现为骨皮质不连续,呈现中断。由于X线平片检查中对于髋臼、髌骨、踝关节后踝、肱骨内上髁、第4、5掌骨基底部中细小骨折线因影像的重叠未能明显显示,故易发生误诊,而在MSCT后处理技术检查中,行MSCT扫描后,再经MPR SSD VRT多方面重建,其中MPR轴位可明显见掌骨基底存在细小骨折线,且对于肱骨内上髁游离的细小骨碎片也可清晰显示。结论 MSCT后处理技术诊断四肢骨关节骨折的正确符合率更高,对于实际在但未能明显表现的隐匿性骨折、骨折部位、位置以及与周围组织关系更能清晰立体的显现,进而更有利于临床医生进行观察和诊断。     

Coronary fly-through or virtual angioscopy using dual-source MDCT data

Coronary fly-through or virtual angioscopy (VA) has been studied ever since its invention in 2000. However, application was limited because it requires an optimal computed tomography (CT) scan and time-consuming post-processing. Recent advances in post-processing software facilitate easy construction of VA, but until now image quality was insufficient in most patients. The introduction of dual-source multidetector CT (MDCT) could enable VA in all patients. Twenty patients were scanned using a dual-source MDCT (Definition, Siemens, Forchheim, Germany) using a standard coronary artery protocol. Post-processing was performed on an Aquarius Workstation (TeraRecon, San Mateo, Calif.). Length travelled per major branch was recorded in millimetres, together with the time required in minutes. VA could be performed in every patient for each of the major coronary arteries. The mean (range) length of the automated fly-through was 80 (32–107) mm for the left anterior descending (LAD), 75 (21–116) mm for the left circumflex artery (LCx), and 109 (21–190) mm for the right coronary artery (RCA). Calcifications and stenoses were visualised, as well as most side branches. The mean time required was 3 min for LAD, 2.5 min for LCx, and 2 min for the RCA. Dual-source MDCT allows for high quality visualisation of the coronary arteries in every patient because scanning with this machine is independent of the heart rate. This is clearly shown by the successful VA in all patients. Potential clinical value of VA should be determined in the near future. This work was presented as posters at the NASCI 2006 and the ESCR 2006     

Assessment of global left ventricular functional parameters: analysis of every second short-axis Magnetic Resonance Imaging slices is as accurate as analysis of consecutive slices

The purpose of this study was to assess whether accurate global left-ventricular (LV) functional parameters can be obtained by analyzing every second short-axis magnetic resonance imaging cine series instead of consecutive slices, in order to reduce post-processing time. Forty patients, were scanned on a 1.5 T MRI-system (Magnetom Sonata, Siemens Medical Systems, Erlangen, Germany) using a steady-state free precession (SSFP) sequence. A stack of short-axis cine series from above the mitral valve through the apex was acquired. Post-processing was started at the most basal slice of the left ventricle, in which at least 50% of the circumference was myocardium. End-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), ejection fraction (EF) and LV mass (LVM), were calculated. Data analysis was repeated, but now only every second slice was analyzed. Bland–Altman analysis showed slightly lower values for all LV parameters when only every second slice was analyzed, ranging from 1.7% difference for EF (limits of agreement −3.5 to 5.0) to 4.6% for SV (limits of agreement −7.2 to 15.0). Analysis of every second slice for quantification of global LV function is time-saving and as accurate as analysis of consecutive slices.     

An intelligent interface for freehand strain imaging

We present a new, intelligent interface for freehand strain imaging, which has been designed to support clinical trials investigating the potential of ultrasonic strain imaging for diagnostic purposes across a broad range of target pathologies. The aim with this interface is to make scanning easier and to help clinicians learn the necessary scanning technique quickly, by providing real time feedback indicating the quality of the strain data as they are produced. The methods require a pixel-level indicator of estimation precision, which can be calculated in-line with strain estimation. This is exploited in novel approaches to normalisation, persistence and display. The effect of each component is indicated in the results with examples from in vitro and in vivo scanning. As well as providing real-time feedback, the images are easier to interpret because data at unacceptably low signal-to-noise ratios do not reach the display. Additionally, the level of noise in the displayed images is actually reduced compared with other methods that use the same strain estimates with the same level of persistence. The interface also considerably reduces the difficulty in producing volumes of strain data from freehand three-dimensional scans.     

MSCT在血管性腹痛诊断中的价值

目的:探讨非消化系统疾病引起腹部疼痛的MSCT表现及其诊断价值。方法:回顾性分析经CT检查和临床随访确诊的42例血管源性腹痛患者的CT资料,包括CT平扫、增强扫描及后处理(多平面重建、曲面重建、最大密度投影、容积再现、表面遮蔽法)进行血管成像的图像。结果:上腹部血管狭窄17例,动脉炎1例;腹膜后纤维化1例;动脉夹层9例;壁间血肿5例;动脉瘤8例,肠系膜挫伤并腹膜后血肿1例。结论:MSCT增强扫描结合后处理技术能较好地发现血管源性腹痛的部位、原因及范围,是诊断血管源性腹痛的较好检查手段。     

64层螺旋CT在肋骨骨折诊断中的应用价值

目的探讨64层螺旋CT各种后处理技术在肋骨骨折诊断中的应用价值。方法对108例胸部外伤患者先行胸部正位及双斜位DR检查,再行64层螺旋CT容积扫描,将全部数据传送到随机工作站,采取多平面重建（MPR）、曲面重建（CPR）、最大密度投影（MIP）及容积再现（VR）等后处理技术,了解有无骨折及骨折情况,并对各项检查结果对比分析。结果MPR或CPR对隐匿性骨折,细小骨折,尤其是不全骨折显示较好;MIP对肋软骨骨折显示较好;VR对有重叠。移位的骨折显示好,定位准确;各种方法联合应用可显著提高肋骨骨折诊断正确率。结论64层螺旋CT后处理技术对胸部外伤肋骨骨折诊断有重要的临床价值。     

Event related potential analysis of stimulus over-selectivity

Stimulus over-selectivity is a phenomenon often displayed by individuals with many forms of developmental and intellectual disabilities, and also by individuals lacking such disabilities who are under cognitive strain. It occurs when only one of potentially many aspects of the environment controls behavior. Adult participants were trained and tested on a trial-and-error discrimination learning task, with a concurrent memory load task, and displayed over-selectivity. Participants’ brain responses were also monitored and analyzed using an electroencephalogram (EEG). The results demonstrated a significant difference between the event-related potentials generated to the over-selected and under-selected stimuli. Although there was no difference in the P300a wave between over- and under-selected stimuli, the P300b wave was associated with over-selected, but not under-selected stimuli. This finding suggests that, in this context, the under-selected stimulus did not elicit ERP activity typically associated with novelty, which, in turn, suggests that over-selectivity may not be entirely an attention-based effect.     

螺旋CT扫描及后期处理对肺叶间裂的诊断分析

目的 探讨螺旋CT扫描及后期处理显示肺叶间裂的诊断价值.方法 采用64层螺旋CT对54例胸部CT扫描且未见异常患者和26例证实肺叶间裂附近病变的患者进行扫描及后期重建处理,分析不同层厚的斜裂、水平裂及叶间变异情况进行比较.结果1.25 mm层厚斜裂显示情况,线状影占89.81％,显著优于2.50 mm层厚的75.00％,差异有统计学意义(x2=8.51,P＜0.05);在2.50 mm层厚线状影占75.00％,显著优于3.75 mm层厚的42.60％,差异有统计学意义(x2=27.45,P＜0.05);水平裂在1.25 mm层厚扫描影像线状影占11.11％,17.75％显示为乏血管区影,73.14％为带状影;对1.25mm层厚影像通过三维重建技术在矢状位、冠状位及横断面进行重组,结果显示右侧斜裂(x2=238.65,P＜0.05)、右侧水平裂(x2=328.79,P＜0.05)和左侧水平裂(x2=377.44,P＜0.05)比较,差异均有统计学意义.结论 多层螺旋CT扫描后处理对于肺叶间裂的显示具有明显优势,特别是1.25 mm层厚的重组影像,能够从不同方位进行分析,对于肺部疾病的诊断有很高的参考价值.