下肢步进摄影获取下肢全长片的精确与可靠性（英文）

背景：精确和可靠的下肢全长片在胫骨高位截骨和膝关节置换前准备和置换后评估中都非常重要。目的：通过下肢步进摄影一次性曝光成像方法获取下肢全长片,并对其进行测量分析。方法：对 13 例膝骨性关节炎伴膝内翻患者进行站立位和平卧位的下肢步进摄影获取下肢全长片,由骨科医师在 X 射线底片上用量角器测量下肢力线角,由放射科医师在计算机屏幕上进行下肢力线角的测量。对所得数据进行差异对比和相关系数研究。结果与结论：应用下肢步进摄影法一次曝光所得的 X 射线下肢全长片具有较高的精确性和可靠性,手工测量和计算机辅助测量有很好的相关性 （r=0.638-0.975）。说明下肢步进摄影获取下肢全长片是一种快捷,简便而有效的检查方法。     

Quantitative analysis of cardiovascular MR images

The diagnosis of cardiovascular disease requires the precise assessment of both morphology and function. Nearly all aspects of cardiovascular function and flow can be quantified nowadays with fast magnetic resonance (MR) imaging techniques. Conventional and breath-hold cine MR imaging allow the precise and highly reproducible assessment of global and regional left ventricular function. During the same examination, velocity encoded cine (VEC) MR imaging provides measurements of blood flow in the heart and great vessels. Quantitative image analysis often still relies on manual tracing of contours in the images. Reliable automated or semi-automated image analysis software would be very helpful to overcome the limitations associated with the manual and tedious processing of the images. Recent progress in MR imaging of the coronary arteries and myocardial perfusion imaging with contrast media, along with the further development of faster imaging sequences, suggest that MR imaging could evolve into a single technique (‘one stop shop’) for the evaluation of many aspects of heart disease. As a result, it is very likely that the need for automated image segmentation and analysis software algorithms will further increase. In this paper the developments directed towards the automated image analysis and semi-automated contour detection for cardiovascular MR imaging are presented.     

Assessment of resting perfusion defects in patients with acute myocardial infarction: comparison of myocardial contrast echocardiography, combined first-pass/delayed contrast-enhanced magnetic resonance imaging and 99mTC-sestamibi SPECT

Background Information on the accuracy of both magnetic resonance imaging (MRI) and myocardial contrast echocardiography (MCE) for the identification of perfusion defects in patients with acute myocardial infarction is limited. We evaluated the accuracy of MRI and MCE, using Single Photon Emission Computed Tomography (SPECT) imaging as reference technique.Methods Fourteen consecutive patients underwent MCE, MRI and ^99mTc-MIBI SPECT after acute myocardial infarction to assess myocardial perfusion. MCE was performed by Harmonic Power Angio Mode, with end-systolic triggering 1:4, using i.v. injection of Levovist^®. First-pass and delayed enhancement MRI was obtained after i.v administration of Gadolinium-DTPA. At MCE, homogeneous perfusion was considered as normal and absent or “patchy” perfusion as abnormal. At MRI, homogenous contrast enhancement was defined as normal whereas hypoenhancement at first-pass followed by hyperenhancement or persisting hypoenhancement in delayed images was defined as abnormal.Results At MCE 153 (68%) of segments were suitable for analysis compared to 220 (98%) segments at MRI (p<0.001). Sensitivity, specificity and accuracy of MCE for segmental perfusion defects in these 153 segments were 83, 73 and 77%, respectively. Sensitivity, specificity and accuracy of MRI were 63, 82, and 77%, respectively. MCE and MRI showed a moderate agreement with SPECT (k: 0.52 and 0.46, respectively). The agreement between MCE and MRI was better (k: 0.67) that the one of each technique with SPECT.Conclusion MCE and MRI may be clinically useful in the assessment of perfusion defects in patients with acute myocardial infarction, even thought MCE imaging may be difficult to obtain in a considerable proportion of segments when the Intermittent Harmonic Angio Mode is used.     

A robust point-matching algorithm for autoradiograph alignment

We present a novel method for the geometric alignment of autoradiographs of the brain. The method is based on finding the spatial mapping and the one-to-one correspondences (or homologies) between point features extracted from the images and rejecting non-homologies as outliers. In this way, we attempt to account for the local, natural and artifactual differences between the autoradiograph slices. We have used the resulting automated algorithm on a set of left prefrontal cortex autoradiograph slices, specifically demonstrated its ability to perform point outlier rejection, validated its robustness property using synthetically generated spatial mappings and provided an anecdotal visual comparison with the well-known iterated closest-point (ICP) algorithm. Visualization of a stack of aligned left prefrontal cortex autoradiograph slices is also provided.     

Automated delineation of white matter fiber tracts with a multiple region-of-interest approach

White matter fiber bundles of the brain can be delineated by tractography utilizing multiple regions-of-interest (MROI) defined by anatomical landmarks. These MROI can be used to specify regions in which to seed, select, or reject tractography fibers. Manual identification of anatomical MROI enables the delineation of white matter fiber bundles, but requires considerable training to develop expertise, considerable time to carry out and suffers from unwanted inter- and intra-rater variability. In a study of 20 healthy volunteers, we compared three methodologies for automated delineation of the white matter fiber bundles. Using these methodologies, fiber bundle MROI for each volunteer were automatically generated. We assessed three strategies for inferring the automatic MROI utilizing nonrigid alignment of reference images and projection of template MROI. We assessed the bundle delineation error associated with alignment utilizing T1-weighted MRI, fractional anisotropy images, and full tensor images. We confirmed the smallest delineation error was achieved using the full tensor images. We then assessed three projection strategies for automatic determination of MROI in each volunteer. Quantitative comparisons were made using the root-mean-squared error observed between streamline density images constructed from fiber bundles identified automatically and by manually drawn MROI in the same subjects. We demonstrate that a multiple template consensus label fusion algorithm generated fiber bundles most consistent with the manual reference standard.     

Quantitative parameters of myocardial perfusion with contrast echocardiography in human beings: Influence of triggering mode

To facilitate quantitation of myocardial contrast echocardiography (MCE) in human beings, dual- or triple-triggered flash imaging has been advocated. However, the effect of this modality on quantitative blood-flow parameters of MCE is not known. Accordingly, MCE was quantitated in 71 myocardial regions of 22 patients (age: 57 +/- 16 years) during continuous infusion of Optison (12-18 mL/h). Two sets of images with end-systolic gating (1:1, 1:2, 1:3, 1:4, 1:6, and 1:8) from the apical 4-chamber view were acquired: single and dual triggering for the first 15 patients; and single and triple triggering for the other 7 patients. During gated imaging, MCE of the first, second, and third frame were quantitated. Curves of intensity versus pulsing intervals were fitted to an exponential function: y = A (1-e(-betat)). Where beta is myocardial blood velocity or the rate of rise of myocardial contrast intensity (MCI), and A is myocardial blood volume or the plateau of MCI reached. Continuous imaging, and the second and third frame in 1:1 gating only, provided similar intensity to precontrast imaging. Beyond 1:1 gating, MCI of the second frame in dual triggering mode gradually increased with incremental pulsing interval. This was still present but less pronounced in triple triggering. During dual and triple triggering, a lower beta was observed compared with single triggering. Application of image subtraction with the flash procedure further decreased beta, A, and the A(*)beta product, a quantitative parameter of blood flow by MCE. Thus, flash subtraction imaging alters the quantitative parameters of myocardial blood velocity and flow derived from MCE. Continuous imaging, and the second or third frame in flash imaging at 1:1 gating only, result in MCI similar to precontrast imaging and can be used for background subtraction to quantitate MCE parameters.     

Measurement of myocardial blood flow velocity reserve with myocardial contrast echocardiography in patients with suspected coronary artery disease: comparison with quantitative gated Technetium 99m sestamibi single photon emission computed tomography.

BACKGROUND: The ability of high and low mechanical index (MI) imaging methods during myocardial contrast echocardiography (MCE) to assess the physiologic significance of coronary stenoses were compared with technetium 99m sestamibi single photon emission computed tomography (SPECT) in patients. METHODS: Intermittent ultraharmonic imaging (high MI) and power modulation angio (low MI) were performed during continuous infusions of the echo-enhancing contrast agent, Optison, at rest and after dipyridamole stress in 39 patients. Technetium 99m sestamibi SPECT was performed simultaneously. Images from the 3 apical windows were divided into 6 walls. Myocardial blood flow (MBF) velocity and MBF velocity reserve were quantified from pulsing interval versus acoustic intensity MCE curves in each wall using postprocessed images. RESULTS: Approximately 25% of the myocardial walls could not be analyzed from MCE because of artifacts. MBF velocity and MBF derived from both MCE methods increased significantly after dipyridamole in healthy patients (n = 143 and 129 walls for high and low MI, respectively), compared with those with either reversible (n = 11 and 10 walls for high and low MI, respectively) or fixed defects (n = 18 and 14 walls for high and low MI, respectively) on SPECT. Consequently, MBF velocity and MBF reserve were significantly greater for patients with normal perfusion. Receiver operator characteristic curves obtained for MBF velocity reserve provided a sensitivity and specificity of 82% and 87%, respectively, for high MI; versus 64% and 96%, respectively, for low MI imaging after uninterpretable images were excluded from analysis. CONCLUSIONS: Both high and low MI MCE imaging techniques can be used to determine the presence of perfusion defects as identified by technetium 99m sestamibi SPECT. Low MI imaging methods have a number of drawbacks that limit its sensitivity compared with high MI techniques.     

携抗P-selectin靶向超声造影剂犬体内超声分子成像

目的 制备携抗P-selectin靶向超声造影剂,探讨其评价心肌缺血再灌注损伤的超声分子成像效果。方法 采用“生物素-亲和素”桥接法制备携抗P-selectin靶向超声造影剂,建立犬心肌缺血再灌注模型,分别注入携抗P-selectin靶向超声造影剂（MBp）和空白超声造影剂（MBc）,行心肌声学造影检查,采图、存盘。应用DFY型超声图像定量分析诊断仪中的彩色编码技术对存储的图像进行脱机处理,观察MBp体内超声分子成像效果。结果 成功制备携抗P-selectin靶向超声造影剂及建立犬心肌缺血再灌注模型。彩色编码图像示MBp行心肌声学造影可见缺血再灌注区心肌显著增强;MBc于缺血再灌注区心肌造影无明显增强。结论 应用携抗P-selectin靶向超声造影剂行心肌声学造影检查能准确检测再灌注治疗后犬心肌缺血再灌注损伤。     

A new method for improving functional-to-structural MRI alignment using local Pearson correlation

Accurate registration of Functional Magnetic Resonance Imaging (FMRI) T2-weighted volumes to same-subject high-resolution T1-weighted structural volumes is important for Blood Oxygenation Level Dependent (BOLD) FMRI and crucial for applications such as cortical surface-based analyses and pre-surgical planning. Such registration is generally implemented by minimizing a cost functional, which measures the mismatch between two image volumes over the group of proper affine transformations. Widely used cost functionals, such as mutual information (MI) and correlation ratio (CR), appear to yield decent alignments when visually judged by matching outer brain contours. However, close inspection reveals that internal brain structures are often significantly misaligned. Poor registration is most evident in the ventricles and sulcal folds, where CSF is concentrated. This observation motivated our development of an improved modality-specific cost functional which uses a weighted local Pearson coefficient (LPC) to align T2- and T1-weighted images. In the absence of an alignment gold standard, we used three human observers blinded to registration method to provide an independent assessment of the quality of the registration for each cost functional. We found that LPC performed significantly better (p<0.001) than generic cost functionals including MI and CR. Generic cost functionals were very often not minimal near the best alignment, thereby suggesting that optimization is not the cause of their failure. Lastly, we emphasize the importance of precise visual inspection of alignment quality and present an automated method for generating composite images that help capture errors of misalignment.     

Automated lumen definition from 30 MHz intravascular ultrasound images

One prerequisite for standard clinical use of intravascular ultrasound imaging is rapid evaluation of the data. The main quantities to be extracted from the data are the size and the shape of the lumen. Until now, no accurate, robust and reproducible method to obtain the lumen boundaries from intravascular ultrasound images has been described. In this study, 21 different (semi-)automated binary-segmentation methods for determining the lumen are compared with manual segmentation to find an alternative for the laborious and subjective procedure of manual editing. After a preprocessing step in which the catheter area is filled with lumen-like grey values, all approaches consist of two steps: (i) smoothing the images with different filtering methods and (ii) extracting the lumen by an object definition method. The combination of different filtering methods and object definition methods results in a total of 21 methods and 80 experiments. The results are compared with a reference image, obtained from manual editing, by use of four different quality parameters—two based on squared distances and two based on Mahalanobis distances. The evaluation has been carried out on 15 images, of which seven are obtained before balloon dilation and eight after balloon dilation. While for the post-dilation images no definite conclusions can be drawn, an automated contour model applied to images smoothed with a large kernel appears to be a good alternative to manual contouring. For pre-dilation images a fully automated active contour model, initialized by thresholding, preceded by filtering with a small-scale median filter is the best alternative for manual delineation. The results of this method are even better than manual segmentation, i.e. they are consistently closer to the reference image than the average distance of all individual manual segmentations.     

Real-time myocardial blood flow imaging in normal human beings with the use of myocardial contrast echocardiography.

Triggered myocardial contrast echocardiography (MCE) has been used successfully to quantify myocardial blood flow and assess coronary stenosis in animal models, but practical considerations have limited its broad clinical use. Real-time MCE may have practical advantages to assess perfusion and real time myocardial blood flow in human beings. We compared real-time MCE with triggered imaging in 23 normal human volunteers by using an investigational ultrasound contrast agent (DMP-115) and a commercially available ultrasound platform (Acuson Sequoia). Peak myocardial opacification (reflecting myocardial blood volume) after contrast infusion was quantified digitally in gray scale units (GU). In 13 subjects, myocardial blood flow reserve was assessed during dipyridamole infusion with the use of intermittent destruction-replenishment techniques. Real-time MCE resulted in a 30- to 45-GU increase from baseline compared with a 20- to 70-GU increase with triggered imaging. Real-time MCE showed no statistical difference in opacification (P = .131 by analysis of variance) among any of the myocardial regions of interest. Triggered imaging resulted in heterogeneous opacification among the regions of interest (P < .05 by analysis of variance). Dipyridamole did not significantly change peak myocardial opacification (myocardial blood volume) for either technique. Quantification of flow reserve revealed that myocardial blood flow reserve for the dipyridamole group was 3.6 +/- 0.4 (mean +/- 1 standard error of the mean). Real-time MCE is feasible in normal human volunteers and provides homogenous opacification of the myocardium. Furthermore, quantification of myocardial blood flow with real-time MCE in normal human beings produces results that are consistent with the known physiology of the coronary microcirculation.     

Novel Automated Motion Compensation Technique for Producing Cumulative Maximum Intensity Subharmonic Images

The aim of this study was to develop a novel automated motion compensation algorithm for producing cumulative maximum intensity (CMI) images from subharmonic imaging (SHI) of breast lesions. SHI is a nonlinear contrast-specific ultrasound imaging technique in which pulses are received at half the frequency of the transmitted pulses. A Logiq 9 scanner (GE Healthcare, Milwaukee, WI, USA) was modified to operate in grayscale SHI mode (transmitting/receiving at 4.4/2.2 MHz) and used to scan 14 women with 16 breast lesions. Manual CMI images were reconstructed by temporal maximum-intensity projection of pixels traced from the first frame to the last. In the new automated technique, the user selects a kernel in the first frame and the algorithm then uses the sum of absolute difference (SAD) technique to identify motion-induced displacements in the remaining frames. A reliability parameter was used to estimate the accuracy of the motion tracking based on the ratio of the minimum SAD to the average SAD. Two thresholds (the mean and 85% of the mean reliability parameter) were used to eliminate images plagued by excessive motion and/or noise. The automated algorithm was compared with the manual technique for computational time, correction of motion artifacts, removal of noisy frames and quality of the final image. The automated algorithm compensated for motion artifacts and noisy frames. The computational time was 2 min compared with 60–90 minutes for the manual method. The quality of the motion-compensated CMI-SHI images generated by the automated technique was comparable to the manual method and provided a snapshot of the microvasculature showing interconnections between vessels, which was less evident in the original data. In conclusion, an automated algorithm for producing CMI-SHI images has been developed. It eliminates the need for manual processing and yields reproducible images, thereby increasing the throughput and efficiency of reconstructing CMI-SHI images. The usefulness of this algorithm can be further extended to other imaging modalities. (E-mail: flemming.forsberg@jefferson.edu)     

Potential pitfalls of visualization of myocardial perfusion by myocardial contrast echocardiography with harmonic gray scale B-mode and power Doppler imaging

OBJECTIVE: The present study compared the regional variation of myocardial signal intensity in visualizing myocardial perfusion by myocardial contrast echocardiography (MCE) between harmonic gray scale and power Doppler imaging. METHODS: MCE was performed in 12 patients by electrocardiographic (ECG)-gated intermittent triggered MCE with harmonic gray scale and power Doppler imaging following slow intravenous injection of 0.5 ml contrast agent (Optison). The interval between the ECG triggers (pulsing interval) was increased from every heart beat (1:1) to every 2 (1:2), 4 (1:4), and 8 (1:8) cardiac cycles to allow incremental microbubble (contrast agent) replenishment. The MCE images were recorded when attenuation produced by the left ventricular cavity was minimal. The background-subtracted videointensity was measured in 7 segments in an apical 4-chamber view: 3 (apical, mid, and basal) septal segments, 3 (apical, mid, and basal) lateral segments, and 1 apex segment (apical cap). RESULTS: The background-subtracted videointensity for each segment was greater with the power Doppler than the gray scale imaging (p < 0.01). With the gray scale imaging, the background-subtracted videointensity in the basal septal segment demonstrated a negative value at all pulsing intervals, and the value (-9 +/- 13) was significantly lower than that (22 +/- 20) in the apical lateral segment at a pulsing interval of 1:8 (p < 0.01). With power Doppler imaging, the background-subtracted videointensity was high even in the basal septal segment (112 +/- 33), and no significant difference was observed among each segment. CONCLUSIONS: The findings indicate that quantitative assessment of myocardial perfusion based upon background-subtracted video-intensity may be difficult in the far field with harmonic gray scale imaging although the attenuation is not apparent by visual analysis. Harmonic power Doppler is more sensitive for detecting basilar perfusion in the far field compared with harmonic gray scale imaging.     

A deep learning approach with temporal consistency for automatic myocardial segmentation of quantitative myocardial contrast echocardiography

Quantitative myocardial contrast echocardiography (MCE) has been proved to be valuable in detecting myocardial ischemia. During quantitative MCE analysis, myocardial segmentation is a critical step in determining accurate region of interests (ROIs). However, traditional myocardial segmentation mainly relies on manual tracing of myocardial contours, which is time-consuming and laborious. To solve this problem, we propose a fully automatic myocardial segmentation framework that can segment myocardial regions in MCE accurately without human intervention. A total of 100 patients’ MCE sequences were divided into a training set and a test set according to a 7: 3 proportion for analysis. We proposed a bi-directional training schema, which incorporated temporal information of forward and backward direction among frames in MCE sequences to ensure temporal consistency by combining convolutional neural network with recurrent neural network. Experiment results demonstrated that compared with a traditional segmentation model (U-net) and the model considering only forward temporal information (U-net?+?forward), our framework achieved the highest segmentation precision in Dice coefficient (U-net vs U-net?+?forward vs our framework: 0.78?±?0.07 vs 0.79?±?0.07 vs 0.81?±?0.07, p?<?0.01), Intersection over Union (0.65?±?0.09 vs 0.66?±?0.09 vs 0.68?±?0.09, p?<?0.01), and lowest Hausdorff Distance (32.68?±?14.6 vs 28.69?±?13.18 vs 27.59?±?12.82 pixel point, p?<?0.01). In the visual grading study, the performance of our framework was the best among these three models (52.47?±?4.29 vs 54.53?±?5.10 vs 57.30?±?4.73, p?<?0.01). A case report on a randomly selected subject for perfusion analysis showed that the perfusion parameters generated by using myocardial segmentation of our proposed framework were similar to that of the expert annotation. The proposed framework could generate more precise myocardial segmentation when compared with traditional methods. The perfusion parameters generated by these myocardial segmentations have a good similarity to that of manual annotation, suggesting that it has the potential to be utilized in routine clinical practice.

     

二次谐波显像评价冠脉血流储备和狭窄程度的实验研究

目的：探讨二次谐波显像在定量评价冠脉血流储备和冠脉狭窄程度的价值。方法：采用二次谐波显像技术对１１条冠脉不同狭窄程度的动物模型进行心肌声学造影。结果：正常或狭窄冠脉灌注区心肌的造影时间－强度曲线的曲线下面积（ＡＵＣ）在罂粟碱介入前后的相对变化率与用电磁流量计测定的冠脉血流量的相对变化率即冠脉血流储备的相关性良好（ｒ＝０．７７,Ｐ＝０．０００２）;而且狭窄冠脉支配的心肌缺血区在罂粟碱介入前后ＡＵＣ的相对变化率与冠脉狭窄程度也有一定的相关性（ｒ＝０．７２,Ｐ＝０．０２。结论：二次谐波显像技术可以定量评价冠脉狭窄后冠脉血流储备的变化,并且在一定范围内定量反映冠脉狭窄程度     

Pseudo ground truth based nonrigid registration of myocardial perfusion MRI

This paper presents a novel nonrigid registration method for myocardial perfusion magnetic resonance (MR) images. To overcome the rapid intensity change due to contrast enhancement, we propose to register the observed sequence to a pseudo ground truth, which is a motion/noise free sequence that is estimated from the observed one, and having almost identical intensity variations as the original sequence. The pseudo ground truth and the elastic deformation fields for the observed sequence are obtained by minimizing an energy functional integrating both the registration error and the spatiotemporal constraints on the pseudo ground truth in an expectation-maximization framework. We have tested the proposed nonrigid registration method on 20 cardiac perfusion MR scans. The proposed method successfully compensated the elastic deformation of the heart in most scans according to visual validation. For quantitative validation, we propagated manually drawn myocardial contours in one frame to other frames according to the deformation fields obtained by applying different registration methods. The root mean square distance between the propagated contour and the gold standard is 2.11mm if only global translation is compensated, and 1.87mm after nonrigid registration, as compared with 2.80mm for serial demons registration and 2.77mm for a free-form deformation approach using normalized mutual information as the similarity measure, both of which adversely increased the error due to misregistration.     

Adenosine myocardial contrast echo in intermediate severity coronary stenoses: a prospective two-center study

Background We sought to evaluate the role of adenosine myocardial contrast echocardiography (MCE) for the determination of functional relevance of coronary stenoses with intermediate angiographic severity and compared the results to single photon imaging (SPECT). We hypothezised that sole assessment of myocardial blood volume changes during adenosine on MCE would indicate functional stensosis relevance when accompanied by increased myocardial oxygen consumption (MVO2). Methods Fifty-seven patients with ≥1 coronary stenosis underwent adenosine MCE (ultraharmonic imaging) and exercise SPECT. On MCE, myocardial blood volume was assessed and constant or increased myocardial opacification during adenosine coupled with increased MVO2 was defined as normal and decreased opacification as abnormal. Results Rate–pressure product significantly increased during adenosine in all patients due to reflex tachycardia following mild hypotension, indicative of increased MVO2. Concordance between MCE and SPECT for the detection of reversible myocardial perfusion defects was 89% (κ = 0.83). Comparison of regions between rest and during adenosine as opposed to comparison to remote regions of the same stage was important for accurate assessment because concordance betweenn MCE and SPECT was less on separate assessment at rest (73%, κ = 0.40) compared to stress (91%, κ = 0.81, P < 0.05) mainly due to territories scored normal on SPECT and abnormal on MCE. Conclusions Assessment of myocardial blood volume changes during adenosine using MCE can be used for the determination of the functional relevance of coronary stenoses of intermediate angiographic severity if MVO2 is increased during adenosine.     

心肌声学造影定量评价缺血预适应对犬心肌缺血再灌注损伤的保护作用

目的应用新技术心肌声学造影（MCE）评价缺血预适应（IP）对犬心肌缺血再灌注（IR）损伤的保护作用。 方法将15条杂种犬随机分为两组：IR组，持续缺血3h后再灌注2h；IP＋IR组，在持续缺血前进行4次短暂性缺血5min，中间间隔5min再灌注。采用前降支动脉套扎建立IP开胸犬模型，分别于基础状态、缺血3h和再灌注2h行MCE；测量两组左室射血分数（EF），计算EF恢复值；处死犬后，采用2％红四氮唑将心肌染色，测量坏死区（NA）和危险区（RA）面积，计算NA／RA，与MCE缺损面积比较。 结果两组缺血3h和再灌注2hEF值较基础状态明显下降，再灌注2h后均有改善；再灌注2hIP＋IR组EF恢复程度好于IP组。各组缺血再灌注后心内膜下心肌出现不同程度的坏死区，MCE和TTC染色2种方法测量值高度正相关。MCE和TTC染色显示IP＋IR组NA／RA值较IR组降低。 结论MCE为定量评价IP对IR损伤的保护作用提供了一种有效方法。     

An integrated approach to segmentation and nonrigid registration for application in image-guided pelvic radiotherapy

External beam radiotherapy (EBRT) has become the preferred options for nonsurgical treatment of prostate cancer and cervix cancer. In order to deliver higher doses to cancerous regions within these pelvic structures (i.e. prostate or cervix) while maintaining or lowering the doses to surrounding non-cancerous regions, it is critical to account for setup variation, organ motion, anatomical changes due to treatment and intra-fraction motion. In previous work, manual segmentation of the soft tissues is performed and then images are registered based on the manual segmentation. In this paper, we present an integrated automatic approach to multiple organ segmentation and nonrigid constrained registration, which can achieve these two aims simultaneously. The segmentation and registration steps are both formulated using a Bayesian framework, and they constrain each other using an iterative conditional model strategy. We also propose a new strategy to assess cumulative actual dose for this novel integrated algorithm, in order to both determine whether the intended treatment is being delivered and, potentially, whether or not a plan should be adjusted for future treatment fractions. Quantitative results show that the automatic segmentation produced results that have an accuracy comparable to manual segmentation, while the registration part significantly outperforms both rigid and nonrigid registration. Clinical application and evaluation of dose delivery show the superiority of proposed method to the procedure currently used in clinical practice, i.e. manual segmentation followed by rigid registration.