磁共振灌注加权成像与弥散加权成像在脑胶质瘤分级诊断中的应用

目的:探讨磁共振灌注加权成像(perfusion weighted imaging,PWI)与弥散加权成像(diffusion weighted imaging,DWI)在脑胶质瘤分级诊断中的应用价值。方法:选取2012年1月-2017年6月在我院就诊并经病理证实为脑胶质瘤患者100例,其中高、低级别胶质瘤患者各44、56例。对所有患者行PWI、DWI检查,比较肿瘤不同区域表观扩散系数(apparent diffusion coefficient,ADC)、局部脑血流量(regional cerebral blood flow,rCBF),不同级别肿瘤实质区、瘤周水肿区rADC、rrCBF,根据ROC曲线分析rADC、rrCBF对不同级别胶质瘤的诊断阈值、敏感性、特异性。结果:与对侧相应正常脑实质比较,瘤周水肿区及肿瘤实质区ADC、rCBF均显著升高(P0.05);与瘤周水肿区比较,肿瘤实质区ADC、rCBF均显著升高(P0.05)。高级别肿瘤实质区rADC显著低于低级别肿瘤实质区(P0.05),rrCBF显著高于肿瘤实质区(P0.05)。高级别瘤周水肿区与低级别瘤周水肿区rADC间无显著差异(P0.05),高级别瘤周水肿区rrCBF显著高于低级别瘤周水肿区(P0.05)。在对高、低级别脑胶质瘤的分级中,rADC、rrCBF的曲线下面积(under the receiver operating characteristic curve,AUC)分别为0.957、0.978,均0.9。rADC诊断不同分级胶质瘤的敏感度是90.12%,特异度是95.26%,诊断阈值是13.12;rrCBF诊断不同分级胶质瘤的敏感度是92.31%,特异度是98.57%,诊断阈值是2.62。rADC与rrCBF诊断不同分级胶质瘤敏感度、特异度间无显著差异(P0.05)。结论:PWI、DWI能够为脑胶质瘤的分级诊断提供参考依据。     

3.0T 1H-MRS对脑胶质瘤及脑转移瘤的鉴别诊断

目的：利用3.0T氢质子磁共振波谱对胶质瘤和转移瘤的肿瘤组织区、瘤周水肿区进行细胞代谢物水平的检测,试图找出胶质瘤和脑转移瘤的鉴别诊断的依据,以及胶质瘤高、低级别组间的差别。方法：对经病理证实的20例高级别胶质瘤组、16例低级别胶质瘤组和19例脑转移瘤组患者,先行MRI平扫及增强扫描,波谱均在增强扫描的基础上获得,使用MR点分辨波谱序列,检测肿瘤组织区、瘤周水肿组织区NAA/Cr、Cho/Cr、NAA/Cho、NAA、Cho、Cr、Lip/Lac等值,进行比较。结果：（1）高级别胶质瘤与转移瘤在肿瘤组织区NAA/Cr代谢物浓度的比值有统计学意义。（2）高、低级别胶质瘤肿瘤组织内Cho/Cr比值有统计学意义。（3）转移瘤与高、低级别胶质瘤在瘤周水肿区NAA/Cr,以及低级别胶质瘤与转移瘤Cho/Cr代谢物浓度的比值有统计学意义;高级别胶质瘤与转移瘤瘤周区NAA代谢物浓度有明显差异。（4）胶质瘤高、低级别组间在肿瘤周围区NAA峰、Cho峰及NAA/Cho Cho/Cr代谢物浓度比值有统计学意义。（5）高级别胶质瘤和转移瘤分别与低级别胶质瘤在肿瘤组织区及瘤周水肿区Lip/Lac有显著性差异（P〈0.01）。结论：利用氢质子波谱可对胶质瘤和转移瘤进行鉴别诊断;Cho/Cr及NAA/Cho比值可对胶质瘤进行分级;Lip/Lac峰的出现与肿瘤的恶性度呈正相关,但不特异。     

磁共振波谱成像结合扩散加权成像在脑胶质瘤及脑转移瘤鉴别诊断中的意义

目的:评估磁共振波谱成像(Proton Magnetic Resonance Spectroscopy,1H-MRS)联合磁共振扩散加权成像(Diffusion Weighted Imaging,DWI)在鉴别脑胶质瘤及孤立的脑转移瘤中的作用。方法:应用3.0T磁共振扫描仪,对临床手术确诊及组织病理学诊断证实的49例脑肿瘤患者(35例多形性胶质母细胞瘤,14例脑转移瘤)进行常规磁共振成像、磁共振波谱成像及磁共振扩散加权成像,并并对获得的数据进一步测量瘤内及瘤周区的代谢比、N-乙酰天门冬氨酸(NAA)、胆碱(Cho)、肌酸(Cr)值以及表观弥散系数(ADC值),分析两肿瘤组之间不同参数的统计学差异。此外,我们研究了感兴趣区域(ROI)的大小对肿瘤区域的病变扩散性能潜在影响。结果:胶质母细胞瘤瘤周N-乙酰天门冬氨酸(NAA)、肌酸(Cr),胆碱(Cho)/Cr,Cho/NAA和r CBV显著高于颅内转移瘤(P0.05);ADC值在两肿瘤组之间无显著差异(P0.05)。结论:在瘤周区1H-MRS有助于鉴别胶质母细胞瘤与单发的脑转移瘤。在瘤内扩散性的定量特性依赖ROI大小的设置。     

MR弥散加权成像对鉴别诊断良恶性椎体压缩性骨折的临床价值研究

目的：探讨MR弥散加权成像（DWI）鉴别诊断良恶性椎体压缩性骨折的临床价值。方法：对57例经临床或病理证实的椎体良恶性压缩性骨折患者行矢状位T1M、T2WI、T2WI／FS及DWI扫描,研究其在常规序列和DWI序列上的表现,将常规MR序列和DWI序列检出率进行比较,测量正常椎体及病变椎体的表观弥散系数（ADC）值,并进行统计学分析。结果：（1）MR常规序列和DWI序列（b=500s／mm2）表现：良性椎体压缩性骨折呈长T1长或等T2改变,T2WI／FS呈高信号,DWI可以呈高信号、等信号及低信号;恶性椎体压缩性骨折呈长T1长T2信号,大部分病灶T2WUFS及DWI呈高信号,少数变现为低信号;（2）MR常规序列和DWI序列（b=500s／mm2）病灶检出率的比较：T1WI、T2WI／FS及DWI序列病灶检出率均高于T2WI序列,其间的差别有显著性意义（P〈0．01）,T1WI、T2WI／FS及DWI序列病灶检出率之间无显著性差异（P〉0．01）;（3）ADC值比较：在DWI（b=500s／mm2）上,良性组ADC值为（2．03±0．83）×10^3mm^2/s,恶性组ADC值为（1．37±0．75）×10^-3mm^2/s,正常组ADC值为（0．36±0．21）×10^-3mm^2／s,成像条件相同时,良性组高于恶性组,两组间有明显的统计学意义（P〈0．05）。结论：DWI可较好的反映椎体的弥散特征,ADC值作为量化指标可对良恶性椎体压缩性骨折进行可靠鉴别。     

胶质瘤中CT联合MR动态扫描的诊断价值及其表观弥散系数的定量研究

摘要 目的：探讨胶质瘤中电子计算机断层扫描（CT）联合核磁共振（MR）动态扫描的诊断价值及其表观弥散系数（ADC）定量价值,以促进胶质瘤的有效早期诊断。方法：2017年4月到2021年3月选择在本院进行诊治的颅内肿瘤患者68例作为研究对象,所有患者均给予CT联合MR动态扫描,记录ADC值并判断诊断价值。结果：在68例患者中,病理诊断为胶质瘤38例（胶质瘤组）,非胶质瘤30例（非胶质瘤组）。胶质瘤组的CT出血、水肿、跨中线、界限不清等特征与非胶质瘤组对比差异有统计学意义（P<0.05）。胶质瘤组多表现为T1WI低信号、T2WI高信号,非胶质瘤组多表现为T1WI等信号或低信号、T2WI高信号,对比差异有统计学意义（P<0.05）。胶质瘤组的MR ADCmax、ADCmedian、ADCmin都低于非胶质瘤组（P<0.05）。胶质瘤中CT联合MR动态扫描诊断为胶质瘤37例,非胶质瘤31例,CT联合MR动态扫描诊断胶质瘤的敏感性与特异性为97.4 %（37/38）和100.0 %（30/30）。结论：CT联合MR动态扫描诊断胶质瘤具有很好的敏感性与特异性,ADC值能有效反映病灶组织的病理特征,为临床上提供了一种较为安全、有效的胶质瘤影像检查方法。     

DTI定量参数对脑胶质瘤的诊断价值及其与血管内皮生长因子、细胞核增殖相关抗原的关系

目的:探讨扩散张量成像(DTI)定量参数对脑胶质瘤的诊断价值及其与血管内皮生长因子(VEGF)、细胞核增殖相关抗原(Ki-67)的关系。方法:选取2014年6月到2017年6月期间在我院接受治疗的90例脑胶质瘤患者,根据病理分级的不同分为中低级别组(n=46)和高级别组(n=44),比较两组患者表观扩散系数(ADC)值、各向异性分数(FA)值、相对表观扩散系数(rADC)值、相对各向异性分数(rFA)值、VEGF和Ki-67的阳性率,分析ADC值、FA值、rADC值、rFA值与VEGF、Ki-67表达的相关性。结果:高级别组的ADC值、FA值、rADC值和rFA值低于中低级别组(P0.05)。高级别组病理组织中VEGF、Ki-67的阳性表达率高于中低级别组(P0.05)。经Spearman相关分析显示,ADC值、FA值、rADC值和rFA值与VEGF、Ki-67的表达水平均呈负相关(P0.05)。结论:DTI定量参数与脑胶质瘤病理分级和VEGF、Ki-67的表达水平密切相关。     

兔大腿VX2移植瘤模型磁共振扩散成像研究

采用大腿肌肉注射法建立兔VX2肿瘤模型,于造模后第7天、14天及21天进行磁共振成像(MRI)平扫、增强及扩散加权成像(DWI)检查,观察不同时期MRI表现。并于造模后第21天对照大体标本测量结果比较DWI及T2WI图像肿瘤最大径,同时比较肿瘤实体部分与髂窝内转移淋巴结的表观弥散系数(ADC)值。结果显示,造模后第7天,12只模型兔MRI常规及DWI图像均可见成瘤;第14天,2例肿瘤内出现坏死灶;第21天,12例肿瘤内均出现坏死,DWI图像可发现局部淋巴结转移灶,DWI及T2WI图像肿瘤最大径与大体标本测量结果差别无统计学意义。髂窝内转移淋巴结的ADC值与原发肿瘤实体部分ADC值间差别无统计学意义。DWI可以监测兔大腿VX2肿瘤生长,有效区分肿瘤早期坏死成分,并判断相应引流区域淋巴结的性质。     

弥散加权成像联合血清CEA、TFF1、sE-cadherin对乳腺良恶性肿块的鉴别价值研究

摘要 目的：探讨弥散加权成像（DWI）联合血清癌胚抗原（CEA）、三叶因子1（TFF1）、可溶性上皮钙黏蛋白（sE-cadherin）对乳腺良恶性肿块的鉴别价值。方法：选择2020年1月至2022年1月中国中医科学院广安门医院收治的81例乳腺肿块患者,所有患者均接受DWI检查并记录标准化表观弥散系数（ADC）,检测血清CEA、TFF1、sE-cadherin水平。以手术病理或空芯针活检病理学结果为准,分析ADC联合血清CEA、TFF1、sE-cadherin鉴别乳腺良恶性肿块的价值。结果：经病理学检查确诊恶性乳腺肿块29例（恶性组）,良性乳腺肿块52例（良性组）。恶性乳腺肿块T1WI低信号影或等信号影,T2WI 呈高信号影或混杂信号,DWI呈高信号影。恶性组ADC值低于良性组（P＜0.05）,血清CEA、TFF1、sE-cadherin水平高于良性组（P＜0.05）。联合ADC值和血清CEA、TFF1、sE-cadherin鉴别乳腺肿块良恶性的曲线下面积为0.869,高于单独指标的0.677、0.681、0.654、0.581。结论：乳腺恶性肿块DWI图像呈高信号影,ADC值降低。乳腺恶性肿块患者血清CEA、TFF1、sE-cadherin水平增高,联合ADC值和血清CEA、TFF1、sE-cadherin可有效鉴别乳腺肿块性质。     

胶质母细胞瘤术后MRI特征及其意义

目的:探讨胶质母细胞瘤术后瘤周梗塞的MRI特征,并评价其临床意义.方法:收集54例胶质母细胞瘤患者的临床、病理及影像学资料,全部患者于术后72小时内进行了MRI检查,并在6个月内进行MRI随访复查,回顾性分析术后临床及MRI表现.结果:术后72小时内MRI研究发现39例存在DW1局灶性弥散受限,病变位于肿瘤切除后空穴区附近.随访MRI研究发现90%的弥散受限病灶已发展成为囊性脑软化,提示原来的局灶性弥散受限为脑梗塞表现,增强扫描44%的梗塞区有异常强化.9例手术后并发神经功能缺失,其中6例与MRI梗塞的分布区域密切相关.结论:恶性胶质瘤术后DWI弥散受限是一种脑梗塞表现,并具有一定临床意义,MRI随访观察中梗塞区异常强化容易误诊为肿瘤复发.     

弥散加权成像联合磁共振波谱分析在脑梗死中的应用研究

目的探讨脑梗死弥散加权成像（DWI）和磁共振波谱分析（MRS）的特点和影响因素,及二者对评估脑梗死的临床价值。方法采用Philips Achieva 1.5T双梯度超导磁共振扫描仪,对72例临床疑是脑梗死患者行常规T1WI、T2WI、FLAIR、DWI、MRS检查,在工作站上测定梗死核心区、内缘区、外缘区、周围区和镜像区的ADC值和代谢物Lac、NAA、Cr、Cho、NAA/Cr、Lac/Cr、Lac/NAA值。结果 DWI显示的梗死灶范围较常规MRI像更加准确、清晰;超急性期、急性期、亚急性期和慢性期梗死核心区的Lac/Cr值和Lac/NAA值高于对侧镜像区,ADC值和NAA/Cr值低于对侧镜像区,存在统计学差异（P〈0.05）;DWI的影响因素有b值、扩散系数、T2穿透效应和各向异性等,MRS的影响因素有磁场均匀性、压水压脂性能、体素、TE与TR、组织代谢物浓度和波谱采集链等。结论 DWI结合MRS能更加全面地评估缺血半暗带,更精确地对脑梗死进行分期和定位。     

Optical hyperspectral imaging in microscopy and spectroscopy – a review of data acquisition

Rather than simply acting as a photographic camera capturing two‐dimensional (x, y) intensity images or a spectrometer acquiring spectra (λ), a hyperspectral imager measures entire three‐dimensional (x, y, λ) datacubes for multivariate analysis, providing structural, molecular, and functional information about biological cells or tissue with unprecedented detail. Such data also gives clinical insights for disease diagnosis and treatment. We summarize the principles underpinning this technology, highlight its practical implementation, and discuss its recent applications at microscopic to macroscopic scales.

Datacube acquisition strategies in hyperspectral imaging x, y, spatial coordinates; λ, wavelength.     

Wearable scanning photoacoustic brain imaging in behaving rats

A wearable scanning photoacoustic imaging (wPAI) system is presented for noninvasive brain study in behaving rats. This miniaturized wPAI system consists of four pico linear servos and a single transducer‐based PAI probe. It has a dimension of 50 mm × 35 mm × 40 mm, and a weight of 26 g excluding cablings. Phantom evaluation shows that wPAI achieves a lateral resolution of ～0.5 mm and an axial resolution of ～0.1 mm at a depth of up to 11 mm. Its imaging ability is also tested in a behaving rat, and the results indicate that wPAI is able to image blood vessels at a depth of up to 5 mm with intact scalp and skull. With its noninvasive, deep penetration, and functional imaging ability in behaving animals, wPAI can be used for behavior, cognition, and preclinical brain disease studies.

     

Novel biomedical applications of Cerenkov radiation and radioluminescence imaging

The main goals of this review is to provide an up-to-date account of the different uses of Cerenkov radiation (CR) and radioluminescence imaging for pre-clinical small animal imaging. We will focus on new emerging applications such as the use of Cerenkov imaging for monitoring radionuclide and external radiotherapy in humans. Another novel application that will be described is the monitoring of radiochemical synthesis using microfluidic chips.Several pre-clinical aspects of CR will be discussed such as the development of 3D reconstruction methods for Cerenkov images and the use of CR as excitation source for nanoparticles or for endoscopic imaging.We will also include a discussion on radioluminescence imaging that is a more general method than Cerenkov imaging for the detection using optical methods of alpha and gamma emitters.     

Molecular probes for fluorescent sensing of metal ions in non-mammalian organisms

While metal ions play an important role in the proper functioning of all life, many questions remain unanswered about exactly how different metals contribute to health and disease. The development of fluorescent probes, which respond to metals, has allowed greater understanding of the cellular location, concentration and speciation of metals in living systems, giving a new appreciation of their function. While the focus of studies using these fluorescent tools has largely been on mammalian organisms, there has been relatively little application of these powerful tools to other organisms. In this review, we highlight recent examples of molecular fluorophores, which have been applied to sensing metals in non-mammalian organisms.     

Maximizing content across scales: Moving multimodal microscopy and mesoscopy toward molecular imaging

Molecular imaging aims to depict the molecules in living patients. However, because this aim is still far beyond reach, patchworks of different solutions need to be used to tackle this overarching goal. From the vast toolbox of imaging techniques, we focus on those recent advances in optical microscopy that image molecules and cells at the submicron to centimeter scale. Mesoscopic imaging covers the “imaging gap” between techniques such as confocal microscopy and magnetic resonance imagingthat image entire live samples but with limited resolution. Microscopy focuses on the cellular level; mesoscopy visualizes the organization of molecules and cells into tissues and organs. The correlation between these techniques allows us to combine disciplines ranging from whole body imaging to basic research of model systems. We review current developments focused on improving microscopic and mesoscopic imaging technologies and on hardware and software that push the current sensitivity and resolution boundaries.     

Wide‐field color imaging of scatter‐based tissue contrast using both high spatial frequency illumination and cross‐polarization gating

This study characterizes the scatter‐specific tissue contrast that can be obtained by high spatial frequency (HSF) domain imaging and cross‐polarization (CP) imaging, using a standard color imaging system, and how combining them may be beneficial. Both HSF and CP approaches are known to modulate the sensitivity of epi‐illumination reflectance images between diffuse multiply scattered and superficially backscattered photons, providing enhanced contrast from microstructure and composition than what is achieved by standard wide‐field imaging. Measurements in tissue‐simulating optical phantoms show that CP imaging returns localized assessments of both scattering and absorption effects, while HSF has uniquely specific sensitivity to scatter‐only contrast, with a strong suppression of visible contrast from blood. The combination of CP and HSF imaging provided an expanded sensitivity to scatter compared with CP imaging, while rejecting specular reflections detected by HSF imaging. ex vivo imaging of an atlas of dissected rodent organs/tissues demonstrated the scatter‐based contrast achieved with HSF, CP and HSF‐CP imaging, with the white light spectral signal returned by each approach translated to a color image for intuitive encoding of scatter‐based contrast within images of tissue. The results suggest that visible CP‐HSF imaging could have the potential to aid diagnostic imaging of lesions in skin or mucosal tissues and organs, where just CP is currently the standard practice imaging modality.      

Smartphone-based multimodal tethered capsule endoscopic platform for white-light,narrow-band,and fluorescence/autofluorescence imaging

Multimodal low-cost endoscopy is highly desirable in poor resource settings such as in developing nations. In this work, we developed a smartphone-based low-cost, reusable tethered capsule endoscopic platform that allows white-light, narrowband, and fluorescence/autofluorescence imaging of the esophagus. The ex-vivo studies of swine esophagus were performed and compared with a commercial endoscope to test the white-light imaging capabilities of the endoscope. The efficacy of the capsule for narrow-band imaging was tested by imaging the vascularization of the tongue. To determine the autofluorescence/fluorescence capability of the endoscope, fluorescein dye with different concentrations was imaged. Furthermore, swine esophagus injected with fluorescein dye was imaged using the fluorescence/autofluorescence and the white-light imaging modules, ex-vivo. The overall cost of the capsules is approximately 12 €, 15 €, and 42 € for the white light imaging, the narrow-band imaging, and the fluorescence/autofluorescence imaging respectively. In addition, the cost of the laser source module required for the narrow-band imaging and the fluorescence/autofluorescence imaging is approximately 218 €. This device will open the possibility of imaging the esophagus in underprivileged areas.     

Multi‐ATOM: Ultrahigh‐throughput single‐cell quantitative phase imaging with subcellular resolution

A growing body of evidence has substantiated the significance of quantitative phase imaging (QPI) in enabling cost‐effective and label‐free cellular assays, which provides useful insights into understanding the biophysical properties of cells and their roles in cellular functions. However, available QPI modalities are limited by the loss of imaging resolution at high throughput and thus run short of sufficient statistical power at the single‐cell precision to define cell identities in a large and heterogeneous population of cells—hindering their utility in mainstream biomedicine and biology. Here we present a new QPI modality, coined multiplexed asymmetric‐detection time‐stretch optical microscopy (multi‐ATOM) that captures and processes quantitative label‐free single‐cell images at ultrahigh throughput without compromising subcellular resolution. We show that multi‐ATOM, based upon ultrafast phase‐gradient encoding, outperforms state‐of‐the‐art QPI in permitting robust phase retrieval at a QPI throughput of >10 000 cell/sec, bypassing the need for interferometry which inevitably compromises QPI quality under ultrafast operation. We employ multi‐ATOM for large‐scale, label‐free, multivariate, cell‐type classification (e.g. breast cancer subtypes, and leukemic cells vs peripheral blood mononuclear cells) at high accuracy (>94%). Our results suggest that multi‐ATOM could empower new strategies in large‐scale biophysical single‐cell analysis with applications in biology and enriching disease diagnostics.      

Nanoscale spectroscopy and imaging of hemoglobin

Sub diffraction limited infrared absorption imaging of hemoglobin was performed by coupling IR optics with an atomic force microscope. Comparisons between the AFM topography and IR absorption images of micron sized hemoglobin features are presented, along with nanoscale IR spectroscopic analysis of the metalloprotein. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Intraoperative multispectral and hyperspectral label‐free imaging: A systematic review of in vivo clinical studies

Multispectral and hyperspectral imaging (HSI) are emerging optical imaging techniques with the potential to transform the way surgery is performed but it is not clear whether current systems are capable of delivering real‐time tissue characterization and surgical guidance. We conducted a systematic review of surgical in vivo label‐free multispectral and HSI systems that have been assessed intraoperatively in adult patients, published over a 10‐year period to May 2018. We analysed 14 studies including 8 different HSI systems. Current in‐vivo HSI systems generate an intraoperative tissue oxygenation map or enable tumour detection. Intraoperative tissue oxygenation measurements may help to predict those patients at risk of postoperative complications and in‐vivo intraoperative tissue characterization may be performed with high specificity and sensitivity. All systems utilized a line‐scanning or wavelength‐scanning method but the spectral range and number of spectral bands employed varied significantly between studies and according to the system's clinical aim. The time to acquire a hyperspectral cube dataset ranged between 5 and 30 seconds. No safety concerns were reported in any studies. A small number of studies have demonstrated the capabilities of intraoperative in‐vivo label‐free HSI but further work is needed to fully integrate it into the current surgical workflow.