Performance Evaluation of Computer Aided Diagnostic Tool (CAD) for Detection of Ultrasonic Based Liver Disease

Recent advances in digital imaging technology have greatly enhanced the interpretation of critical/pathology conditions from the 2-dimensional medical images. This has become realistic due to the existence of the computer aided diagnostic tool. A computer aided diagnostic (CAD) tool generally possesses components like preprocessing, identification/selection of region of interest, extraction of typical features and finally an efficient classification system. This paper enumerates on development of CAD tool for classification of chronic liver disease through the 2-D image acquired from ultrasonic device. Characterization of tissue through qualitative treatment leads to the detection of abnormality which is not viable through qualitative visual inspection by the radiologist. Common liver diseases are the indicators of changes in tissue elasticity. One can show the detection of normal, fatty or malignant condition based on the application of CAD tool thereby, further investigation required by radiologist can be avoided. The proposed work involves an optimal block analysis (64 × 64) of the liver image of actual size 256 × 256 by incorporating Gabor wavelet transform which does the texture classification through automated mode. Statistical features such as gray level mean as well as variance values are estimated after this preprocessing mode. A non-linear back propagation neural network (BPNN) is applied for classifying the normal (vs) fatty and normal (vs) malignant liver which yields a classification accuracy of 96.8%. Further multi classification is also performed and a classification accuracy of 94% is obtained. It can be concluded that the proposed CAD can be used as an expert system to aid the automated diagnosis of liver diseases.     

AIDR3D重建算法超低剂量640层CT结肠成像息肉检出能力的实验研究

目的：实验研究三维自适应迭代剂量降低（AIDR3D）重建算法超低剂量640层CT结肠成像的息肉检出能力。方法制作10段猪结肠息肉模型,每段模型上有30枚1～15 mm模拟息肉。所有模型用640层CT机扫描,球管电压120 kVp ,电流剂量分别为10、20、30、40、50 mAs。滤波反投影（FBP）和AIDR3D算法重建后获得CT结肠成像的图像。两位不知道扫描电流剂量及重建算法的影像科医生独立分析图像。每位影像科医生的息肉检出信心分5个等级,用Kappa分析评价2位影像科医生息肉检出信心的一致性。根据剂量长度乘积计算辐射剂量。统计分析5种扫描电流剂量、2种重建算法的图像检出息肉的敏感性。结果两位影像科医生对3000枚息肉检出信心一致性好（κ＝0．740）。20 mAs扫描并AIDR3D重建对1～＜6、6～＜11、11～15 mm息肉检出敏感性与50 mAs扫描并FBP重建相同,均达100％;有效辐射剂量1．62 mSv较50 mAs扫描并FBP重建的4．04 mSv降低60．00％,差异有统计学意义（P＜0．05）。10 mAs扫描并AIDR3D重建对1～＜6 mm息肉检出敏感性77％低于50 mAs扫描并FBP重建的100％,差异有统计学意义（P＜0．05）,对6～＜11 mm息肉检出敏感性98％也低于50 mAs扫描并FBP重建的100％。结论超低剂量20 mAs扫描并AIDR3D重建640层CT结肠成像息肉检出能力能够与标准低剂量50 mAs扫描并FBP重建媲美,检出敏感性达100％;而且有效辐射剂量降低60．0％,只有1．62 mSv。     

多层螺旋CT仿真肠镜与结肠镜检查技术在发现结肠肿瘤的应用价值对比

目的探讨多层螺旋CT三维重建与仿真肠镜在结肠肿瘤病变诊断中的应用价值并对比结肠镜检查结果。方法对我院2009年1月至2014年1月来我院就诊的疑似结肠占位的患者应用SIEME 64层螺旋CT对200例例患者行一次屏气全结肠容积扫描,并利用工作站进行后处理以获取CT仿真肠镜(CTVC),多平面重建(MPR),表面阴影成像(SSD)和透明显示(Ray sum)图像,并结合原始横断面等图像进行分析,再行结肠镜检查对照。结果与结肠镜相比,CTVC诊断阳性率较结肠镜高,CTVC检出26例结肠镜检查为正常的患者,12例误诊为结肠息肉,检出结直肠癌200例,敏感度为100%,特异度94%。结论多层螺旋CT三维重建及仿真内镜是一种无创伤性的影像学检查方法,对结直肠占位病变的诊断有其独特的优越性尤其是结肠癌诊断的敏感度、特异度及准确度均较高,可作为纤维结肠镜有价值的补充检查手段,能弥补结肠镜检查中的不足,给临床诊断带来巨大前景。     

64层螺旋CT重建层厚及重建间距与CAD肺结节检出准确性的关系分析

目的：评估不同重建层厚及重建间距对Lung Care软件CAD系统检出肺结节准确性的影响.方法：纳入48例肺结节患者,每位患者重建5组数据,层厚/间距分别为：0.75/0.70mm,1/1mm,3/3mm,5/1mm,5/5mm.利用ROC曲线对比不同重建参数时CAD的检测准确性.结果：根据参考标准共检出152个肺结节.在0.75,1mm层厚时的曲线下面积（Az）值（分别为0.86,0.84）均显著高于3,5mm层厚时（3/3,5/1,5/5mm时Az值分别为0.48,0.53,0.40）（P〈0.05）;重叠重建（5/1mm）时,CAD检出肺结节的Az值（Az=0.53）大于5mm层距时（Az=0.40）,二者无显著性差异,但明显低于1mm层厚重建（Az=0.84,P〈0.05）.1mm层厚重建时CAD检出肺结节的灵敏度最高（84%）;0.75mm层厚重建时平均每位患者的假阳性数最低（0.56）.随层厚增加,CAD检出肺结节的平均直径逐渐增大,检出小结节的数目明显下降.结论：使用薄层重建（层厚0.75mm或1mm）图像时,CAD的检出准确性显著高于厚层重建（层厚3mm或5mm）时.重叠重建（5/1mm）可以提高CAD的准确性,但其作用非常有限.     

SCT及HRCT对肺部感染性病变的诊断价值

目的:探讨螺旋CT(SCT)及高分辨率CT(HRCT)对肺部感染性病变的诊断价值。资料与方法:35例经临床与病理证实的肺部感染性病变均作螺旋CT扫描及HRCT扫描。SCT扫描,层厚3mm～10mm,Pitch=1,重建间隔1mm～2mm;HRCT扫描:120kV,120mA,2s,1.5mm层厚,1.5mm间距,512×512矩阵,用BoneALGRITHM算法重建图像。结果:20例肺结核病例SCT扫描15例显示了树芽征及周边卫星病灶,HRCT扫描20例均显示了树芽征及卫星病灶。12例支气管扩张病例,10mmSCT扫描显示支气管扩张10例、印戒征(Signetringsign)8例。HRCT12例均可见支气管扩张及印戒征。3例肺曲霉菌感染SCT及HRCT均有很好显示。结论:SCT及HRCT对肺部感染性疾病及其细节具有良好的显示,以HRCT最有价值。     

An Acoustical Evaluation of Knee Sound for Non-invasive Screening and Early Detection of Articular Pathology

Knee sound signals generated by knee movement are sometimes associated with degeneration of the knee joint surface and such sounds may be a useful index for early disease. In this study, we detected the acoustical parameters, such as the fundamental frequency (F0), mean amplitude of the pitches, and jitter and shimmer of knee sounds, and compared them according to the pathological conditions. Six normal subjects (4 males and 2 females, age: 28.3 ± 2.3 years) and 11 patients with knee problems were enrolled. The patients were divided into the 1st patient group (5 males and 1 female, age: 30.2 ± 10.3 years) with ruptured wounds of the meniscus and 2nd patient group (2 males and 3 females, age: 42.1 ± 16.2 years) with osteoarthritis. The mean values of F0, jitter and shimmer of the 2nd patient group were larger than those of the normal group, whereas those of the 1st patient group were smaller (p < 0.05). Also, the F0 and jitter in the standing position were larger than those in the sitting position in both the 1st and 2nd patient groups (p < 0.05). These results showed good potential for the non-invasive diagnosis and early detection of articular pathologies via an auscultation.     

体位对CT仿真结肠镜成像影响的实验研究

目的:探讨体位对结肠隆起性病变CT仿真结肠镜(CTvirtualcolonoscopy,CTVC)成像的影响。方法:取长约20cm的猪结肠16段,每段制作直径2mm~10mm的息肉模型各6个。结肠适度充气并注入1mm~2mm高的水后,行螺旋CT扫描。每一肠段均扫描2次,使模拟病灶分别位于近地壁和远地壁上。分析两种位置下CTVC病灶的显示效果和检出率。结果:远地壁上模拟息肉显示效果优于近地壁上(Uc=5.998,P<0.01);远地壁上模拟息肉检出率高于近地壁上(分别为100%和75%)(χ2=27.43,P<0.01)。结论:多体位扫描提高了结肠隆起性病变的CTVC显示效果和检出率。     

多层螺旋CT结肠病变的诊断

目的 评价多层螺旋CT结肠成像技术的临床应用价值.方法 回顾性分析我院收治的经手术或结肠镜活检病理证实的20例结肠病变患者的影像学资料.16排MSCT对20例患者进行容积扫描和MPR、CTVC、SSD、Raysum等图像后处理.结果 20例中12例结肠癌、1例非霍奇金淋巴瘤、1例残胃癌累及横结肠,CT横断面、MPR、SSD、CTVC、Raysum图像均清晰显示.结肠息肉4例(共12枚),CT横断面显示7枚较大息肉,MPR、SSD、Raysum图像各显示10枚,CTVC清晰显示1 2枚.3例结肠炎症由CT横断面图像,结合MPR、CTVC而诊断.结论 在MSCT结肠成像检查时合理应用后处理技术,有助于结肠病变的诊断.     

Impact of Computerized Order Entry and Pre-mixed Dialysis Solutions for Continuous Veno-Venous Hemodiafiltration on Selection of Therapy for Acute Renal Failure

To investigate the impacts of availability of pre-mixed solutions and computerized order entry on nephrologists’ choice of the initial mode of renal replacement therapy in acute renal failure. We studied 898 patients with acute renal failure in 3 consecutive eras: era 1 (custom-mixed solution; n = 309), era 2 (pre-mixed commercial solution; n = 324), and era 3 (post-computerized order entry; n = 265). The proportion of patients treated with renal replacement therapy and the time from consult to initiation of continuous renal replacement therapy was similar in the 3 eras. Following introduction of the pre-mixed solution, the proportion of patients treated with continuous renal replacement therapy increased (20% vs. 33%; p < 0.05), it was initiated at a lower serum creatinine (353 ± 123 μmol/L vs. 300 ± 80 μmol/L; p < 0.05) and in older patients (53 ± 12 vs. 61 ± 14 years; p < 0.05). There was a progressive increase in the use of continuous veno-venous hemodialysis (18% vs. 79% vs. 100%; p < 0.05) and in the total prescribed flow rate (1,382 ± 546 vs. 2,324 ± 737 vs. 2,900 ± 305 mL/hr 3; p < 0.05). There was no significant impact on mortality. The availability of a pre-mixed solution increases the likelihood of initiating continuous renal replacement therapy in acute renal failure, initiating it at a lower creatinine and for older patients, use of continuous veno-venous hemodialysis and higher prescribed continuous renal replacement therapy dose. Computerized order entry implementation is associated with an additional increase in the use of continuous veno-venous hemodialysis, higher total prescribed dialysis dose, and use of CRRT among an increasing number of patients not on mechanical ventilation. The effect of these changes on patient survival is not significant.