Magnetic resonance imaging for diagnosis and neoadjuvant treatment evaluation in locally advanced rectal cancer:A pictorial review

High-resolution pelvic magnetic resonance imaging(MRI) is the primary method for staging rectal cancer.MRI is highly accurate in the primary staging of rectal cancer;however,it has not proven to be effective in restaging,especially in complete response evaluation after neoadjuvant therapy.Neoadjuvant chemoradiotherapy produces many changes in rectal tumors and on adjacent area,as a result,local tumor extent may not be accurately determined.However,adding diffusion-weighted sequences to the standard approach can improve diagnostic accuracy.In this pictorial review,an overview of the situation of MRI in the staging and re-staging of rectal cancer is exhibited as a pictorial assay.An experience-and literature-based discussion of limitations and difficulties in interpretation are also presented.

Role of magnetic resonance imaging in the diagnostic work up of clinical localized prostate cancer: A review

Imaging plays an increasingly important role in the work up of prostate cancer(PCa) and magnetic resonance imaging(MRI) is generally accepted as the most accurate and promising imaging modality in the local staging of PCa due to its high spatial resolution and excellent soft tissue contrast. The quality and performance of MRI of the prostate has improved dramatically during the last decade. Mainly, the combination of morphological information and functional information on cell density, tissue perfusion or metabolism as provided in multi-parametric prostate MRI(mp MRI) has led to a substantial increase in lesion detection and characterization. The correlation between functional parameters as provided by MRI and the aggressiveness of PCa as determined by the Gleason Score may help in differentiating clinically signifi cant from indolent PCa non-invasively. Besides these pros, radiologists are confronted with an immense amount of information and standardized acquisition, interpretation and reporting of mp MRI is not yet a reality. Furthermore, prostate MRI availability is still limited to high volume centers in many countries; hence, it is not yet a routine tool in common daily practice. Hence, development of guidelines for standardized acquisition, interpretation andreporting of prostate MRI exams is urgently needed in order to provide useful information for treating clinicians. Preferably, multi-centric clinical studies comparing MRI fi ndings to step-section histological specimens are mandatory during the coming years. Furthermore, simplification of the acquisition must be achieved in order to make this imaging modality applicable for daily use in common uro-radiological practice.

Diffusion-weighted magnetic resonance imaging for predicting the response of rectal cancer to neoadjuvant concurrent chemoradiation

AIM:To evaluate the clinical value of diffusion-weighted magnetic resonance imaging(DW-MRI)in predicting the response of rectal cancer to neoadjuvant chemoradiation.METHODS:This prospective study was approved by our institutional review board,and informed consent was obtained from each patient.Fifteen patients(median age 56 years)with locally advanced rectal cancer were treated in our hospital from June 2006 to December 2007.All patients were stageⅢB-C according to the results of MRI and endorectal ultrasound examinations.All patients underwent pelvic irradiation with 45 Gy/25 fx per 35 days.The concurrent chemotherapy regimen consisted of capecitabine 625mg/m2,bid(Monday-Friday),and oxaliplatin 50 mg/m2,weekly.The patients underwent surgery 5-8 wk after the completion of neoadjuvant therapy.T downstaging was defined as the downstaging of the tumor from cT3to ypT0-2 or from cT4 to ypT0-3.Good regression was defined as TRG 3-4,and poor regression was defined as TRG 0-2.Diffusion-weighted magnetic resonance images were obtained prior to and weekly during the course of neoadjuvant chemoradiation,and the apparent diffusion coefficient(ADC)values were calculated from the acquired tumor images.RESULTS:Comparison with the mean pretreatment tumor ADC revealed an increase in the mean tumor ADC during the course of neoadjuvant chemoradiation,especially at the 2ndweek(P=0.004).We found a strong negative correlation between the mean pretreatment tumor ADC and tumor regression after neoadjuvant chemoradiation(P=0.021).In the T downstage and tumor regression groups,we found a significant increase in the mean ADC at the 2ndweek of neoadjuvant therapy(P=0.011;0.004).CONCLUSION:DW-MRI might be a valuable clinical tool to help predict or assess the response of rectal cancer to neoadjuvant chemoradiation at an early timepoint.

Correlations between hippocampal functional connectivity,structural changes,and clinical data in patients with relapsing-remitting multiple sclerosis:a case-control study using multimodal magnetic resonance imaging

Multiple sclerosis is associated with structural and functional brain alterations leading to cognitive impairments across multiple domains including attention,memory,and the speed of information processing.The hippocampus,which is a brain important structure involved in memory,undergoes microstructural changes in the early stage of multiple sclerosis.In this study,we analyzed hippocampal function and structure in patients with relapsing-remitting multiple sclerosis and explored correlations between the functional connectivity of the hippocampus to the whole brain,changes in local brain function and microstructure,and cognitive function at rest.We retrospectively analyzed data from 20 relapsing-remitting multiple sclerosis patients admitted to the Department of Neurology at the China-Japan Union Hospital of Jilin University,China,from April 2015 to November 2019.Sixteen healthy volunteers were recruited as the healthy control group.All participants were evaluated using a scale of extended disability status and the Montreal cognitive assessment within 1 week before and after head diffusion tensor imaging and functional magnetic resonance imaging.Compared with the healthy control group,the patients with relapsing-remitting multiple sclerosis had lower Montreal cognitive assessment scores and regions of simultaneously enhanced and attenuated whole-brain functional connectivity and local functional connectivity in the bilateral hippocampus.Hippocampal diffusion tensor imaging data showed that,compared with the healthy control group,patients with relapsing-remitting multiple sclerosis had lower hippocampal fractional anisotropy values and higher mean diffusivity values,suggesting abnormal hippocampal structure.The left hippocampus whole-brain functional connectivity was negatively correlated with the Montreal cognitive assessment score(r=-0.698,P=0.025),and whole-brain functional connectivity of the right hippocampus was negatively correlated with extended disability status scale score(r=-0.649,P=0.042).The mean diffusivity value of the left hippocampus was negatively correlated with the Montreal cognitive assessment score(r=-0.729,P=0.017)and positively correlated with the extended disability status scale score(r=0.653,P=0.041).The right hippocampal mean diffusivity value was positively correlated with the extended disability status scale score(r=0.684,P=0.029).These data suggest that the functional connectivity and presence of structural abnormalities in the hippocampus in patients with relapse-remission multiple sclerosis are correlated with the degree of cognitive function and extent of disability.This study was approved by the Ethics Committee of China-Japan Union Hospital of Jilin University,China(approval No.201702202)on February 22,2017.

An Improved Jellyfish Algorithm for Multilevel Thresholding of Magnetic Resonance Brain Image Segmentations

Image segmentation is vital when analyzing medical images,especially magnetic resonance(MR)images of the brain.Recently,several image segmentation techniques based on multilevel thresholding have been proposed for medical image segmentation;however,the algorithms become trapped in local minima and have low convergence speeds,particularly as the number of threshold levels increases.Consequently,in this paper,we develop a new multilevel thresholding image segmentation technique based on the jellyfish search algorithm(JSA)(an optimizer).We modify the JSA to prevent descents into local minima,and we accelerate convergence toward optimal solutions.The improvement is achieved by applying two novel strategies:Rankingbased updating and an adaptive method.Ranking-based updating is used to replace undesirable solutions with other solutions generated by a novel updating scheme that improves the qualities of the removed solutions.We develop a new adaptive strategy to exploit the ability of the JSA to find a best-so-far solution;we allow a small amount of exploration to avoid descents into local minima.The two strategies are integrated with the JSA to produce an improved JSA(IJSA)that optimally thresholds brain MR images.To compare the performances of the IJSA and JSA,seven brain MR images were segmented at threshold levels of 3,4,5,6,7,8,10,15,20,25,and 30.IJSA was compared with several other recent image segmentation algorithms,including the improved and standard marine predator algorithms,the modified salp and standard salp swarm algorithms,the equilibrium optimizer,and the standard JSA in terms of fitness,the Structured Similarity Index Metric(SSIM),the peak signal-to-noise ratio(PSNR),the standard deviation(SD),and the Features Similarity Index Metric(FSIM).The experimental outcomes and the Wilcoxon rank-sum test demonstrate the superiority of the proposed algorithm in terms of the FSIM,the PSNR,the objective values,and the SD;in terms of the SSIM,IJSA was competitive with the others.

Volumetric magnetic resonance imaging classification for Alzheimer＇s disease based on kernel density estimation of local features

Background The classification of Alzheimer＇s disease （AD） from magnetic resonance imaging （MRI） has been challenged by lack of effective and reliable biomarkers due to inter-subject variability. This article presents a classification method for AD based on kernel density estimation （KDE） of local features. Methods First, a large number of local features were extracted from stable image blobs to represent various anatomical patterns for potential effective biomarkers. Based on distinctive descriptors and locations, the local features were robustly clustered to identify correspondences of the same underlying patterns. Then, the KDE was used to estimate distribution parameters of the correspondences by weighting contributions according to their distances. Thus, biomarkers could be reliably quantified by reducing the effects of further away correspondences which were more likely noises from inter-subject variability. Finally, the Bayes classifier was applied on the distribution parameters for the classification of AD. Results Experiments were performed on different divisions of a publicly available database to investigate the accuracy and the effects of age and AD severity. Our method achieved an equal error classification rate of 0.85 for subject aged 60-80 years exhibiting mild AD and outperformed a recent local feature-based work regardless of both effects. Conclusions We proposed a volumetric brain MRI classification method for neurodegenerative disease based on statistics of local features using KDE. The method may be potentially useful for the computer-aided diagnosis in clinical settings.

Medical image translation using an edge-guided generative adversarial network with global-to-local feature fusion

In this paper,we propose a framework based deep learning for medical image translation using paired and unpaired training data.Initially,a deep neural network with an encoder-decoder structure is proposed for image-to-image translation using paired training data.A multi-scale context aggregation approach is then used to extract various features from different levels of encoding,which are used during the corresponding network decoding stage.At this point,we further propose an edge-guided generative adversarial network for image-to-image translation based on unpaired training data.An edge constraint loss function is used to improve network performance in tissue boundaries.To analyze framework performance,we conducted five different medical image translation tasks.The assessment demonstrates that the proposed deep learning framework brings significant improvement beyond state-of-the-arts.

基于功能影像学探讨百会治疗失眠的中枢机制

百会为治疗失眠的效穴,临床使用频率高。功能影像学,广义上包括多种成像技术,狭义主要指功能性磁共振成像(fMRI),数据分析方法分为功能分离和功能整合两类,试验设计方案包括任务态(Tb-fMRI)与静息态(Rs-fMRI),静息态因操作简便且能直观反映针刺持续和累积效应而被广泛应用。多项fMRI研究表明,失眠患者在视觉区、感觉运动区、情绪相关脑区等存在局部功能异常,针刺百会单穴或组穴可引起特定脑区如顶叶、额叶、颞叶等的改变,从而改善睡眠。针刺单穴百会主要集中在Rs-fMRI局部一致性(ReHo)、比率低频振幅(fALFF)研究,而针刺百会组穴研究从Rs-fMRI局部一致性(ReHo)、度中心度(DC)、种子连接(FC),以及Tb-fMRI比率低频振幅(fALFF)等方面展开,研究发现不同研究方法和穴位组合下的脑区激活改变存在差异,且针刺百会组穴所调控脑区多于单穴针刺,体现了百会对失眠、认知和情绪的调节作用以及腧穴间的协同作用。然而,针刺百会引起的中枢信号改变复杂,功能影像作为评估失眠的中枢指标虽有潜力,但仍需更规范、深入的研究。

Whole lesion histogram analysis of apparent diffusion coefficient predicts therapy response in locally advanced rectal cancer

BACKGROUND Whole-tumor apparent diffusion coefficient(ADC)histogram analysis is relevant to predicting the neoadjuvant chemoradiation therapy(nCRT)response in patients with locally advanced rectal cancer(LARC).AIM To evaluate the performance of ADC histogram-derived parameters for predicting the outcomes of patients with LARC.METHODS This is a single-center,retrospective study,which included 48 patients with LARC.All patients underwent a pre-treatment magnetic resonance imaging(MRI)scan for primary tumor staging and a second restaging MRI for response evaluation.The sample was distributed as follows:18 responder patients(R)and 30 non-responders(non-R).Eight parameters derived from the whole-lesion histogram analysis(ADCmean,skewness,kurtosis,and ADC10^(th),25^(th),50^(th),75^(th),90^(th) percentiles),as well as the ADCmean from the hot spot region of interest(ROI),were calculated for each patient before and after treatment.Then all data were compared between R and non-R using the Mann-Whitney U test.Two measures of diagnostic accuracy were applied:the receiver operating characteristic curve and the diagnostic odds ratio(DOR).We also reported intra-and interobserver variability by calculating the intraclass correlation coefficient(ICC).RESULTS Post-nCRT kurtosis,as well as post-nCRT skewness,were significantly lower in R than in non-R(both P<0.001,respectively).We also found that,after treatment,R had a larger loss of both kurtosis and skewness than non-R(Δ%kurtosis and Δ skewness,P<0.001).Other parameters that demonstrated changes between groups were post-nCRT ADC10^(th),Δ%ADC10^(th),Δ%ADCmean,and ROIΔ%ADCmean.However,the best diagnostic performance was achieved byΔ%kurtosis at a threshold of 11.85%(Area under the receiver operating characteristic curve[AUC]=0.991,DOR=376),followed by post-nCRT kurtosis=0.78×10^(-3)mm^(2)/s(AUC=0.985,DOR=375.3),Δskewness=0.16(AUC=0.885,DOR=192.2)and post-nCRT skewness=1.59×10^(-3)mm^(2)/s(AUC=0.815,DOR=168.6).Finally,intraclass correlation coefficient analysis showed excellent intraobserver and interobserver agreement,ensuring the implementation of histogram analysis into routine clinical practice.CONCLUSION Whole-tumor ADC histogram parameters,particularly kurtosis and skewness,are relevant biomarkers for predicting the nCRT response in LARC.Both parameters appear to be more reliable than ADCmean from one-slice ROI.

Value of MR contrast media in image-guided body interventions

In the past few years,there have been multiple advances in magnetic resonance (MR) instrumentation,in vivo devices,real-time imaging sequences and interventional procedures with new therapies.More recently,interventionists have started to use minimally invasive image-guided procedures and local therapies,which reduce the pain from conventional surgery and increase drug effectiveness,respectively.Local therapy also reduces the systemic dose and eliminates the toxic side effects of some drugs to other organs.The success of MR-guided procedures depends on visualization of the targets in 3D and precise deployment of ablation catheters,local therapies and devices.MR contrast media provide a wealth of tissue contrast and allows 3D and 4D image acquisitions.After the development of fast imaging sequences,the clinical applications of MR contrast media have been substantially expanded to include pre-during-and post-interventions.Prior to intervention,MR contrast media have the potential to localize and delineate pathologic tissues of vital organs,such as the brain,heart,breast,kidney,prostate,liver and uterus.They also offer other options such as labeling therapeutic agents or cells.During intervention,these agents have the capability to map blood vessels and enhance the contrast between the endovascular guidewire/catheters/devices,blood and tissues as well as direct therapies to the target.Furthermore,labeling therapeutic agents or cells aids in visualizing their delivery sites and tracking their tissue distribution.After intervention,MR contrast media have been used for assessing the efficacy of ablation and therapies.It should be noted that most image-guided procedures are under preclinical research and development.It can be concluded that MR contrast media have great value in preclinical and some clinical interventional procedures.Future applications of MR contrast media in image-guided procedures depend on their safety,tolerability,tissue specificity and effectiveness in demonstrating success of the interventions and therapies.

Abnormal Local Activity and Functional Dysconnectivity in Patients with Schizophrenia Having Auditory Verbal Hallucinations

Auditory verbal hallucination(AVH)is emphasized as a pathological hallmark of schizophrenia.Neuroimaging studies provide evidence linking AVH to overlapping functional abnormalities in distributed networks.However,no clear conclusion has still been reached.This study aimed to further explore the brain activity of patients with schizophrenia having AVH from both local activity(LA)and functional connectivity(FC)insights,while excluding confounding factors from other positive symptoms.A total of 42 patients with AVH(AVH patients group,APG),26 without AVH(non-AVH patients group,NPG),and 82 normal controls(NC)underwent resting-state functional magnetic resonance imaging(fMRI).LA measures,including regional homogeneity(ReHo)and fractional amplitude of low-frequency fluctuations(fALFF),and FC measures were evaluated to understand the neuroimaging mechanism of AVH.APG showed increased ReHo and fALFF in the bilateral putamen(Put)compared with NPG and NC.FC analysis(using bilateral putamen as seeds)revealed that all patients showed abnormal FC of multiple resting state network regions,including the anterior and post cingulate cortex,middle frontal gyrus,inferior parietal gyrus,and left angular gyrus.Interestingly,APG showed significantly decreased FC of insula extending to the superior temporal gyrus and inferior frontal gyrus compared with NPG and NC.The present findings suggested a significant correlation of abnormal LA and dysfunctional putamen-auditory cortical connectivity with the neuropathological mechanism of AVH,providing evidence for the functional disconnection hypothesis of schizophrenia.

The effectiveness of local anesthetic and sodium hyaluronate injection for the posterior disc displacement: A case report

Posterior disc displacement of the temporomandibular joint is rare. We present a unique treatment method and magnetic resonance (MR) images of this condition. The patient was a 43-year-old male with a chief complaint of abnormal occlusion. Regarding the present status, there was no occlusion on the right side. No temporomandibular joint pain, myalgia, or clicking were observed while mouth opening. On MR images, the posterior disc displacement without reduction on the right was observed and it was assumed that occlusal abnormality was due to this condition. We treated him with the following methods. After injection into the superior articular cavity with 2% lidocaine, a sodium hyaluronate preparation was injected followed by intermaxillary traction applied using rubber. The recovery of occlusion was confirmed in follow-up at 5 days after treatment. In the 13th days, the intermaxillary traction was removed. On MR images, the right disc condition was changed to anterior disc displacement with reduction. We consider our treatment methods are effective for this clinical condition.

Detection and Local Staging of Prostate Cancer by 68Ga-PSMA-PET/CT, Comparison with mpMRI and Histopathology

Introduction: 68Ga-PSMA-PET/CT has proven its value in prostate cancer with high positive predictive value for lymph node metastasis and superior detection of distant metastasis. There is growing evidence that 68Ga-PSMA- PET/CT has high sensitivity for detection of tumor lesions in the prostate as well. Studies thus far have mainly been performed in patients prior to prostatectomy. Aim of this study is to evaluate diagnostic accuracy in a mixed population of men with increased risk of prostate cancer and evaluate diagnostic possibilities with respect to extra-capsular extension and seminal vesicle invasion. Methods: The population consisted of a retrospectively included sequential cohort of 69 patients with 68Ga-PSMA-PET/CT and mpMRI available. 68Ga-PSMA-PET/CT was re-evaluated by two readers blinded for mpMRI and clinical information. Likelihood of tumour presence, extra-prostatic extension and seminal vesicle invasion was scored on 5-point Likert scale and localized schematically. Results were compared with mpMRI. Available pathological outcome served as gold standard. SUVmax of index lesions was measured and correlated to index tumor Gleason grade. Results: Clinically significant prostate cancer (Gleason ≥ 3 + 4) was detected in 57 (83%) of 69 patients. Diagnostic accuracy was 89% for PET reader 1, 93% for PET reader 2 and 86% for mpMRI. Lesion concordance of 68Ga-PSMA-PET/CT and mpMRI was 97%. SUVmax of the index lesion correlated to Gleason grade. Sensitivity for extracapsular extension in the prostatectomy group was 62% for PET reader 1, 33% for PET reader 2 and 50% for mpMRI. Specificity was 62% for PET reader 1, 100% for PET reader 2 and 69% for mpMRI. Conclusion: Ga68-PSMA-PET shows high accuracy in the detection of tumor lesions in the prostate. Results on evaluating extra-capsular extension and seminal vesicle invasion are comparable to mpMRI. This study adds to the increasing evidence that 68Ga-PSMA-PET/CT is imperative in detection of prostate cancer prior to biopsy.

Evaluation of dynamic contrast-enhanced MRI in monitoring early response of locally advanced breast cancer to neoadjuvant chemotherapy

Objective： The aim of our study was to assess the value of dynamic contrast-enhanced magnetic resonance imaging （DMRI） in predicting early response to neoadjuvant chemotherapy （NAC） in patients with locally advanced breast cancer （LABC） and to assess the accuracy of DMRI in evaluating residual disease after NAC. Methods： DMRI were per- formed in 43 women with LABC （44 lesions, all were invasive ductal carcinoma） before, after the first and final cycle of NAC. Tumour volume, early enhanced ratio （El）, maximum enhanced ratio （Emax）, and maximum enhanced time （Tmax）, dynamic signal intensity-time curve were obtained during treatment. Residual tumour volumes obtained using DMRI were compared with pathological findings to assess the accuracy of DMRI. Results： After 1st cycle of NAC, the mean volume of responders decreased insignificantly, P 〉 0.05, but after NAC, mean volume of residual tumor decreased significantly （P 〈 0.01）. Morphol- ogy change： 29 cases showed a concentric shrinkage pattern while 7 cases showed a dendritic shrinkage pattern. Significant differences were found in El, Emax and Tmax between responders and non-responders （P 〈 0.05）. After 1st cycle of NAC, El, Emax and Tmax of responders changed significantly （P 〈 0.001）; while there is no significant change in non-responders （P 〉 0.05）. After NAC, dynamic signal intensity-time types were changed in responders, and tended to be significantly flat- tening, while no significant change was found in non-responders. The residual tumour volume correlation coefficient between DMRI and pathology measurements was very high （r = 0.866, P = 0.000）. Conclusion： DMRI is useful to evaluate the early response to NAC in LABC. The presence and volume of residual disease in LABC patients treated with NAC could be ac- curately evaluated by DMRI.

关节镜下自体骨软骨移植对膝关节局限性软骨损伤的临床疗效评价

目的探讨关节镜下自体骨软骨移植术对膝关节局限性软骨损伤的临床疗效,并以磁共振成像(MRI)检查对疗效进行评价。方法选取2018年6月至2021年6月诊治的100例膝关节局限性软骨损伤患者,按随机数字表法分为研究组和对照组,每组各50例。研究组采取关节镜下自体骨软骨移植术,对照组采取微骨折术治疗。采用MRI评估其手术疗效,并记录其术后膝关节软骨愈合时间;采用Lysholm膝关节功能评分表、国际膝关节文献委员会(IKDC)膝关节评估表,评估患者治疗前后膝关节功能变化;统计患者术后并发症发生率。结果研究组关节软骨愈合优良率98.00%,高于对照组84.00%(P<0.05)。两组术前和术后3个月的Lysholm评分、IKDC评分比较差异无统计学意义(P>0.05);术后6、12、24个月,研究组Lysholm评分、IKDC评分均高于对照组(P<0.05)。两组患者术后均无严重并发症,且并发症发生率差异无统计学意义(P>0.05)。研究组术后膝关节软骨愈合时间短于对照组(P<0.05)。结论关节镜下自体骨软骨移植术对膝关节局限性软骨损伤的远期治疗效果显著,可有效改善患者术后膝关节功能,缩短膝关节软骨愈合时间,安全性高。

颈部影像报告和数据系统在MRI诊断早期单纯黏膜型鼻咽癌局部复发中的应用

目的探讨颈部影像报告和数据系统(neck imaging reporting and data systems,NI-RADS)MRI对单纯黏膜型鼻咽癌局部复发(exclusive mucosal local recurrent nasopharyngeal carcinoma,EMLRNPC)与黏膜治疗后改变(mucosal posttreatment changes,MPTC)的诊断价值,尝试为NI-RADS MRI词典中的局灶性黏膜异常建议附加定性扩散加权成像(diffusion-weighted imaging,DWI)标准。材料与方法回顾性分析2015年2月至2023年2月经病理或影像随访确诊的21例EMLRNPC和29例MPTC。先由2名影像医师独立评价MRI表现,进行NI-RADS MRI分类,再进行附加定性DWI标准的改良NI-RADS MRI分类,3个月后,由其中的1名高年资影像医师再次进行分类。采用Cohen’s Kappa检验评估观察者间、观察者内NI-RADS分类一致性。绘制受试者工作特征(receiver operating characteristic,ROC)曲线评价这两种NI-RADS分类对EMLRNPC与MPTC的诊断效能,曲线下面积(area under the curve,AUC)的比较采用DeLong检验。结果NI-RADS MRI、改良NI-RADS MRI的分类观察者间与观察者内一致性为0.69与0.88、0.83与0.96。NI-RADS MRI和改良NI-RADS MRI鉴别诊断ELRNPC与MPTC的AUC、敏感度、特异度为0.845[95%置信区间(confidence interval,CI):0.715~0.932]、100.0%(95%CI:83.9%~100.0%)、69.0%(95%CI:49.2%~84.7%)和0.966(95%CI:0.871~0.997)、100.0%(95%CI:83.9%~100.0%)、93.1%(95%CI:77.2%~99.2%),两种分类的AUC间差异有统计学意义(Z=2.985,P=0.003)。结论NI-RADS MRI与附加定性DWI标准的改良NI-RADS MRI对EMLRNPC与MPTC均具有较高的鉴别诊断价值,改良NI-RADS MRI分类的诊断效能、一致性更高。

基于Non-local的腰椎间盘突出患者多裂肌分割方法

为实现腰椎间盘突出患者多裂肌病灶部位的精确分割,提出了一种基于Non-local的腰椎间盘突出患者多裂肌分割方法。以U-Net网络为基础,通过构造混合池化卷积来代替编码器传统的卷积模块,以提高全局特征与局部特征之间的相关性并融合网络高低维特征,增强了网络提取多裂肌特征的能力。然后,在网络的中间部署了一个由2个级联卷积组成的卷积模块。最后,经过由Non-local模块和3×3的卷积构成的解码器,通过引入注意力机制来更加关注目标的特征并抑制不必要的特征和噪音,从而提高模型的性能。实验结果表明,本方法与经典U-Net算法相比,Dice系数提升了9.5%,Jaccard相似系数提升了11.3%,Hausdorff Distance下降了74.6%。该方法提高了多裂肌脂肪浸润部位的分割精度,为腰椎间盘突出患者多裂肌病灶部位的分割提供了一种有效的方法。

Local Pulse Wave Velocity Estimation in the Carotids Using Dynamic MR Sequences

The current study presents a new protocol for local pulse wave velocity (PWV) measurement using dynamic MR sequences, which have a high temporal resolution (TR < 6 ms). MR images were obtained at two positions along the common carotid artery, separated by a distance of 5 cm. In each phase of a MR series, carotid region was automatically extracted and then its area distension waveform could be obtained. Sixteen volunteers with no symptoms of cardiovascular diseases were studied. For local PWV estimation, three delay estimation principles were tested and produced the following values: intersecting tangents method (M1): 4.72 ± 1.40 m/s, second derivative method (M2): 4.94 ± 1.68 m/s and cross-correlation method (M3): 5.03 ± 1.17 m/s. The cross-correlation method showed a relative high reliability as its least standard deviation.

磁共振联合前列腺特异性抗原评估前列腺癌术后复发的价值

目的分析磁共振(MRI)多参数成像联合血清前列腺特异性抗原(PSA)对前列腺癌根治术后局部复发的诊断价值。方法回顾性收集2018年1月至2022年12月于四川省中西医结合医院行前列腺癌根治术的243例患者临床资料,根据术后1年是否发生局部复发,将其分为局部复发组(n=22)和未复发组(n=221)。记录磁共振弥散成像(DWI)评分、动态对比增强MRI(DCE-MRI)评分及总风险评分,比较两组临床资料、表观扩散系数(ADC)值、DWI评分、DCE-MRI评分、总风险评分及血清PSA水平差异,使用受试者工作特征(ROC)曲线分析ADC值、总风险评分、血清PSA对前列腺癌根治术后局部复发的诊断价值。结果两组年龄、术前前列腺体积、体重指数及吸烟史比较,差异无统计学意义(P>0.05)。复发组临床分期、血清PSA水平及Gleason、DWI、DCE-MRI、总风险评分均高于未复发组(P<0.05),ADC值低于未复发组(P<0.05)。ROC曲线分析显示,ADC值、总风险评分及血清PSA对前列腺癌根治术后局部复发均具有较高的诊断价值(AUC=0.742、0.965、0.940,P<0.05)。结论基于DCE-MRI和DWI的总风险评分与血清PSA水平对前列腺癌根治术后局部复发诊断均有利,二者联合诊断应用价值较高。

3.0T MRI对原发性直肠癌患者术前肿瘤局部浸润程度的评估价值

目的分析3.0T磁共振成像(MRI)对原发性直肠癌患者术前肿瘤局部浸润程度的评估价值。方法回顾性分析127例原发性直肠癌患者临床资料,患者术前均进行3.0T MRI扫描对直肠癌局部浸润征象做出分期诊断,并与术后病理组织学肿瘤T分期进行对照,以组织病理学结果作为金标准,计算3.0T MRI在评价肿瘤局部浸润程度的总的准确性及各分期的准确性、敏感度、特异度、阳性预测值、阴性预测值。结果127例原发性直肠癌患者中,经病理组织学确诊T2分期患者29例,T3分期患者55例,T4分期患者43例,3.0T MRI诊断T2分期患者31例,T3分期患者47例,T4分期患者49例,3.0T MRI诊断T分期与病理组织学诊断对照,kappa一致性为0.663,准确率为77.95%(99/127)。3.0T MRI对原发性直肠癌患者术前肿瘤局部浸润程度的诊断效能各有差异,T4分期的诊断效能较高,T2分期的诊断效能次之,T3分期的诊断效能较差,与病理组织学诊断对照,T2、T3、T4分期的kappa一致性分别为0.695、0.543、0.762,敏感度分别为79.31%、67.27%、90.70%,特异度分别为91.84%、86.11%、88.10%,准确率分别为88.98%、77.95%、88.98%,阳性预测值分别为74.19%、78.72%、79.59%,阴性预测值分别为93.75%、77.50%、94.87%。结论3.0T MRI对原发性直肠癌患者术前肿瘤局部浸润程度有较好的评估价值,尤其是T4分期的诊断效能较高。