基于互信息配准的超声造影运动校正算法

目的 通过动态DICOM造影文件的互信息逐帧配准完成运动校正,减少呼吸和心跳运动对超声造影统计分析结果的影响.方法 使用主轴距配准完成粗配准,然后使用搜索算法和互信息给出精配准.计算每帧图像运动造成的平移和旋转,完成校正.结果 通过配准后的图像进行拟合回归分析时减少了呼吸和心跳运动造成的影响,其分析的拟合度得到提高.结论 该方法可用于超声造影运动校正的逐帧配准.     

3D非刚性图像运动校正在肝DCE-MRI定量成像中的应用

目的探讨3D非刚性图像运动校正在提高肝脏DCE-MRI图像质量和定量参数准确性的应用价值。方法 35例确诊肝细胞癌患者进行自由呼吸下全肝MRI灌注扫描,使用3D对比增强非刚性配准对多期动态增强扫描MRI图像进行图像运动配准,利用肝脏双血供模型和腹主动脉、门静脉时间-浓度曲线作为血管输入函数(VIF),分别获得肝癌、肝实质图像运动校正前后灌注参数(K~(trans)、K_(ep)、Ve、Vp、HPI)。比较图像运动校正前后各组定量参数差异。对运动校正前后图像质量分别进行客观和主观评价。测量病灶最大面积,比较原始图像上校正前后病灶面积的差异。结果使用3D图像运动校正后腹主动脉、门静脉时间-浓度曲线波动幅度缩小,平滑度更好。图像运动校正后肝癌K~(trans)、K_(ep)、Ve、Vp、HPI值均大于校正前,K~(trans)、Ve、Vp,值差异存在统计学差异(P0.05),K_(ep)值两者间无统计学差异(P0.05)。图像运动校正后肝实质K~(trans)、K_(ep)、Ve、Vp、HPI值均大于校正前,K~(trans)、Ve、Vp值差异存在统计学差异(P0.05);K_(ep)值两者间无统计学差异(P0.05);图像运动校正前后HPI值相近,且无统计学差异(P0.05)。肝癌在原始图像上面积平均值运动校正前大于运动校正后,但无统计学意义(P0.05)。校正后肝组织噪声低于矫正前,无统计学意义(P0.05),校正后图像主观评分明显高于矫正前,差异存在统计学意义(P0.05)。结论 3D非刚性运动校正能减少肝脏MRI多期动态增强图像运动伪影,有助于提高灌注定量参数的准确性。     

不同呼吸控制方法对冠状动脉CTA成像质量的研究

在中国冠心病人群中,据文献报道[1]冠状动脉CTA诊断冠状动脉狭窄的极高特异度,可用来作为冠状动脉狭窄的排除性诊断。但是研究显示仍有高达12%的冠状动脉节段不能满足影像学评价[2]。主要的原因是冠状动脉壁的严重钙化以及运动伪影,在影响其图像质量的主要原因中,呼吸运动伪影高居第     

平板运动试验与冠状动脉造影对冠心病诊断的对比分析

目的：通过平板运动试验（TET）与冠状动脉造影（CAG）的对比分析,评价TET诊断冠心病的价值。方法：选取疑诊冠心病患者300例,先后行TET和CAG检查,将两种检查结果对比分析。结果：对照CAG TET敏感性68.91%,特异性73.17%;女性假阳性率高于男性;单一易患因素中以有糖尿病者阳性率高;具备两种或两种以上易患因素者阳性率高。结论：对TET结果应综合分析判断,才能得出正确结论。     

心电图编辑在心律失常患者CT冠状动脉血管造影数据重建中的应用

目的探讨在心律失常患者冠状动脉CTA数据后处理重建过程中,ECG编辑功能对修正相位的应用价值。方法69例心律失常的患者在我院接受了冠状动脉CTA检查,所有患者的扫描数据均因心律不齐而采用了ECG编辑软件进行处理,比较处理前、后的图像质量,评价ECG编辑功能对修正不同类型心律失常相位重建的应用价值。结果69例患者中,偶发房早24例,偶发室早33例,缓慢型房颤5例,快速率房颤3例,频发室早3例,Ⅱ度Ⅰ型窦房阻滞1例。经ECG编辑处理后,图像质量达到优者26例,占38%;良者32例,占46%;中者5例,占7%。图像质量差者6例,占9%。结论ECG编辑功能对改善偶发早搏（房早、室早）、较慢心率下（≤70次/分）房颤患者的CTA图像质量有较大帮助,但对频发早搏、较快心率下的房颤无明显作用。     

256层螺旋CT大范围心电门控扫描的冠状动脉成像质量评价

目的：探讨256层螺旋CT大范围心电门控扫描胸腹部血管联合成像对冠状动脉成像质量的评价.方法：对34例因胸痛就诊的患者用256层螺旋CT行大范围心电门控扫描检查,检查完成后,进行冠状动脉图像重建,并与常规CT冠脉扫描的图像进行比较.结果：行大范围心电门控扫描检查组的冠状动脉图像质量优良率为89.7％ （456/508）,能够满足诊断要求的为95.5％（485/508）,常规冠状动脉扫描组中,图像质量优良率为89.8％（460/512）,能够满足诊断要求的为96.3％ （489/512）.两组的图像优良率无明显差异（χ2=1.072,P=-0.192）.结论：256层螺旋CT大范围心电门控扫描能够满足冠状动脉成像的要求,具有较高的临床应用价值.     

双源CT冠脉显像对老年患者冠脉疾病的诊断价值

目的探讨双源CT的冠脉成像技术对老年患者的诊断价值。方法对我院849例拟诊或确诊老年冠心病患者的心脏双源CT检查结果进行分析,评价双源CT对老年患者冠脉成像的特点及优势。结果双源CT能够清晰显示冠脉并发现冠脉连接/起源异常,对老年患者心肌桥血管的发现比例高达32.86%,并伴随相应节段冠脉异常比例达13.62%。与冠脉造影对比显示,双源CT对冠脉狭窄的阳性病变诊断的敏感度、特异度、阳性预测值、阴性预测值分别为71.43%、92.31%、71.43%、92.31%,准确度达到89.23%。结论双源CT能够较清晰地显示老年患者冠脉的起源和管腔狭窄情况,和金标准冠脉造影比较,显示出较高的准确度,可作为老年患者冠脉疾病了解的初筛手段。     

Accuracy and rate of coronary artery segment visualization with CT angiography for the non-invasive detection of coronary artery stenoses

Objectives To evaluate CT coronary angiography (CTA) when compared with catheter coronary angiography (CCA), for the detection of coronary artery stenoses and rate of optimal coronary artery segment visualization. Method Retrospective, two-center study enrolling 26 patients who underwent CCA and ECG-gated 16-detector CTA (slice thickness 0.6 mm; rotation 500 ms). Results and conclusion 283 segments were available for postprocessing. Sensitivity, specificity, and positive predictive value were, respectively, 80, 100, and 100%, for detecting more than 50% luminal stenoses, when optimally visualized segments were considered, in comparison to CCA. Negative predictive value was excellent (98%). Rate of non-optimally visualized coronary segments was 26%. Most clinical benefits of coronary CT angiography should probably be obtained when it is performed to exclude significant stenoses on selected populations of patients with a low pre-test probability of severe coronary artery disease, and under optimal conditions of controlled heart rate and minimal presence of calcium.     

64层螺旋CT评估冠状动脉狭窄的准确性——与传统冠状动脉造影对照研究

目的通过与CAG的比较,研究64层螺旋CT评估冠状动脉狭窄性病变的准确性。方法收集2005年8月-2006年4月于我院行64层螺旋CT冠状动脉成像和传统冠状动脉造影的60例患者的影像资料,评估64层螺旋CT诊断冠状动脉狭窄性病变及对支架及桥血管诊断的准确性。结果64层螺旋CT诊断冠状动脉≥50%、≥70%、<50%狭窄性病变敏感性分别为96.3%、89.3%、67.3%,特异性分别为94.2%、95.6%、86.2%。64层螺旋CT判断支架内≥50%狭窄的敏感性为100%,特异性为80%;判断桥血管及吻合口通畅的敏感性为100%。结论64层螺旋CT诊断冠状动脉中重度狭窄具有较高的准确性。     

螺旋CT冠脉造影在心脏血管狭窄中的诊断情况分析

目的:探讨多层螺旋C T冠脉造影在心脏血管狭窄中的诊断情况.方法:统计2020年10月—2021年6月在上海市普陀区利群医院进行螺旋CT冠脉造影(CT coronary angiography,CTA)和数字减影血管造影(digital subtraction angiography,DSA)的30例患者,以DSA为诊...     

CT angiography for evaluation of coronary artery disease in inner-city outpatients: an initial prospective comparison with stress myocardial perfusion imaging

To evaluate the utility of CT coronary angiography (CTA) for demonstrating coronary artery disease in inner-city outpatients, we prospectively compared CTA with stress SPECT myocardial perfusion imaging in an ethnically diverse, gender balanced population. All patients gave written informed consent for this IRB approved, HIPAA compliant study. Sixty-one patients completed both CTA and SPECT. About 67% were ethnic minorities, 51% were women. A stenosis of ≥70% on CTA was considered positive. Results were compared with perfusion defects on SPECT and correlated with clinical endpoints (hospital admissions, cardiovascular events, coronary interventions and deaths). CTA and SPECT data were compared with results of coronary angiography, when performed. There was moderate global agreement of 79% (48/61) between CTA and SPECT, κ = 0.483 (SE ± 0.13, P = 0.0001). With SPECT as the reference standard, CTA had sensitivity of 73% (11/15), specificity of 80% (37/46), negative predictive value of 90% (37/41) and positive predictive value of 55% (11/20). Positive SPECT was associated with positive CTA, (P < 0.0001, OR = 22). Eleven (18%) underwent subsequent cardiac catheterization, which was positive in 91% (10/11). CTA and SPECT had positive predictive values of 90 and 83% compared with catheterization. This study lends preliminary evidence to support to the utility of CTA as an alternative modality for the evaluation of CAD in an ethnically diverse, gender balanced inner-city outpatient population. Similar to more homogenous groups, CTA had a high negative predictive value and demonstrated disease occult to SPECT. Further study is necessary to evaluate the impact of CTA on patient outcomes.     

深度学习图像重建算法用于肥胖个体低剂量冠状动脉CT血管成像

目的 观察深度学习图像重建(DLIR)算法用于肥胖个体低剂量冠状动脉CT血管成像(CCTA)的可行性.方法 纳入30例体质量指数(BMI)≥28 kg/m2的疑诊冠状动脉疾病(CAD)患者,以管电压100 kV行CCTA扫描;采用DLIR(DLIR-M组及DLIR-H组)算法重建图像,并与自适应统计迭代重建(ASIR-...     

Modified scan protocol using multislice CT coronary angiography allows high quality acquisitions in obese patients: a case report

Nearly every cardiovascular functional imaging technique has difficulties in dealing with obese patients and MSCT-CA is not an exception. Excluding such large portion of the coronary population remains a grim limitation of the technique and requires thus a comprehensive re-evaluation. In this report, we show that excellent image quality could be achieved in a morbidly obese patient with the aid of proper management of scan protocols and bolus administration. Providing this complex population an accurate, non-invasive imaging technique represents a major step-forward in cardiovascular imaging.     

Polyrigid and polyaffine transformations: A novel geometrical tool to deal with non-rigid deformations – Application to the registration of histological slices

We describe in this paper a novel kind of geometrical transformations, named polyrigid and polyaffine. These transformations efficiently code for locally rigid or affine deformations with a small number of intuitive parameters. They can describe compactly large rigid or affine movements, unlike most free-form deformation classes. Very flexible, this tool can be readily adapted to a large variety of situations, simply by tuning the number of rigid or affine components and the number of parameters describing their regions of influence.The displacement of each spatial position is defined by a continuous trajectory that follows a differential equation which averages the influence of each rigid or affine component. We show that the resulting transformations are diffeomorphisms, smooth with respect to their parameters. We devise a new and flexible numerical scheme to allow a trade-off between computational efficiency and closeness to the ideal diffeomorphism. Our algorithms are implemented within the Insight Toolkit, whose generic programming style offers rich facilities for prototyping. In this context, we derive an effective optimization strategy of the transformations which demonstrates that this new tool is highly suitable for inference.The whole framework is exemplified successfully with the registration of histological slices. This choice is challenging, because these data often present locally rigid deformations added during their acquisition, and can also present a loss of matter, which makes their registration even more difficult.Powerful and flexible, this new tool opens up large perspectives, in non-rigid 3D rigid registration as well as in shape statistics.