DWI在宫颈癌诊断中的应用及其与病理相关性研究

目的探讨弥散加权成像(DWI)在宫颈癌诊断中的应用及其与宫颈癌病理类型的相关性。方法收集该院2013-08~2015-01共88例病理确诊为宫颈癌的盆腔MRI资料,其中鳞癌84例、腺癌4例。鳞癌中Ⅰ级16例、Ⅱ级46例、Ⅲ级22例。同时收集88例非经期或绝经期健康女性的盆腔MRI资料,分别比较宫颈癌与正常宫颈ADC值及鳞癌与腺癌ADC值的差异,绘制ROC曲线并利用曲线下面积评价判断标准的价值;分析不同病理级别宫颈癌的ADC值并分析其相关性。结果宫颈癌ADC值(0.842±0.151)10~(-3)mm~2/s,低于正常宫颈(1.387±0.087)10~(-3)mm~2/s;且鳞癌ADC值(0.835±0.149)10~(-3)mm~2/s低于腺癌(0.999±0.083)10~(-3)mm~2/s,差异均有统计学意义(P0.05)。同时ADC值对区分宫颈癌与正常宫颈,鳞癌与腺癌的ROC曲线下面积(AUC值)分别为0.991、0.908。Ⅰ、Ⅱ、Ⅲ级鳞癌的ADC值分别为(1.059±0.155)、(0.847±0.043)、(0.680±0.084)10~(-3)mm~2/s,且两两之间比较差异有统计学意义(P0.05)。结论宫颈癌的弥散加权成像可以提供形态学以外的信息,不仅有助于诊断宫颈癌,还在一定程度上帮助评估其病理分型与分级,是对常规磁共振检查的一个有益补充。     

磁共振弥散加权成像在糖尿病肾病中的应用

目的探讨磁共振扩散加权成像(DWI)测量糖尿病(DM)肾病(DN)患者肾脏的表观扩散系数(ADC)值对DN的诊断价值。方法选择2010年10月1日至2012年3月1日于该院内分泌科治疗并具有明确诊断及临床分期的68例2型糖尿病(T2DM)患者,依据实验目的分为DM组和DN组,后者又分为DNⅢ期组和DNⅣ期组,其中DM组22例,DN组46例(DNⅢ期组24例,DNⅣ期组22例),所有患者均进行双侧肾脏冠状位磁共振扩散加权成像(DWI)扫描,弥散梯度因子(b值)为(0,600 s/mm2)和(0,1 000 s/mm2)。对DM组及DN组患者肾脏表面弥散系数(ADC)值进行ANOVA分析,明确是否存在差异。结果 b值为600 s/mm2时,DNⅣ期组肾脏ADC值与DM组比较,有统计学差异(P<0.05);DNⅢ期组肾脏ADC值分别与DM组、DNⅣ期组比较没有统计学差异(P>0.05)。b值为1 000 s/mm2时,DNⅢ期组肾脏ADC值与DM组比较有统计学差异(P<0.05);DNⅣ期组肾脏ADC值与DM组比较差异显著(P<0.01);DNⅢ期组肾脏ADC值与DNⅣ期组比较无统计学差异(P>0.05)。结论选用高b值DMI能发现早期DN的肾功能损害,所测量的ADC值与DN的严重程度呈负相关。     

线粒体脑肌病:常规MRI与弥散加权成像及弥散张量成像的比较

线粒体脑肌病是主要累及中枢神经系统和骨骼肌且具有遗传异质性的一组疾病。诊断主要根据肌肉的组织病理学检查、极谱法和分光光度计研究以及线粒体或核DNA基因突变分析。常规T_2加权(T_2W)磁共振成像(MRI)可见不按血管分布的灰质和皮层下白质高信号,白质损害可能与小血管缺血和脱髓鞘有关。作者对1例经活检证实为线粒体脑肌病的患者进行磁共振弥散加权成像、弥散张量成像和质子磁共振波谱(MRS)检查。结果表明弥散加权     

磁共振弥散张量成像在神经疾病中的应用

磁共振弥散张量成像(DTI)是近几年发展起来的水弥散成像技术,它通过脑水分子的弥散性定量反映脑白质纤维束的完整性。文章简要介绍了DTI的基本概念及其在脑梗死、多发性硬化、癫、Alzheimer病和颅内肿瘤等多种神经疾病中的应用。     

60例健康人脑水分子扩散加权成像正常表观扩散系数的定量研究

目的对健康老年人30例(老年组)脑水分子扩散加权成像进行实验研究,并与健康非老年人30例(非老年组)进行对照,探讨年龄因素对健康人脑白质及灰质核团表观扩散系数(apparent diffusion coefficient,ADC)值的影响。方法对2组对象进行脑水分子扩散加权成像,并分别测量额叶和枕叶白质ADC值作为皮质下白质的代表,测量丘脑ADC值作为灰质的代表。结果老年组脑白质ADC平均值(ADCav)为(0．73±0．10)×10-3mm2/s、丘脑为(0．84±0．06)×10-3 mm2／s,非老年组分别为(0．70±0．07)×10-3mm2／s和(0．83±0．08)×10-3mm2／s,2组脑白质差异有统计学意义(P<0．05),丘脑间差异无统计学意义;同组白质和丘脑间差异有统计学意义(P< 0．001)。结论健康人随年龄增长,正常脑白质ADC值呈现微弱的增长趋势,尤其是老年人增长趋势更为明显;定量ADC值分析,对疾病的早期诊断及检测病变的发生、发展有重要的意义;临床研究中在对照组的选取上应注意年龄因素的影响,本研究所得数据可作为进一步研究正常参考值。     

急性脑缺血的弥散和灌注磁共振成像

最近 ,磁共振成像 (MRI) ,特别是弥散加权成像 (DWI)和灌注加权成像 (PWI)的进展 ,已使临床医生具备了区分不可逆性脑梗死和潜在的可逆性缺血半暗带的能力。本文探讨了DWI和PWI的工作原理和应用。随着急性脑缺血溶栓和其他治疗的不断进展 ,在急性卒中的决策方面 ,神经影像学会随时起到越来越重要的作用。     

磁共振弥散加权成像在恶性肿瘤疗效评价方面的应用

恶性肿瘤的发病率呈逐年上升趋势,对人类生存构成严重威胁.所以,早诊早治已成为提高恶性肿瘤预后的关键.大多数恶性肿瘤的治疗方法除手术外,主要为放疗和(或)化疗.目前,临床评价疗效的传统方法是监测实验室指标和CT(或MRI)的肿瘤形态学观察.这些方法通常在治疗数月后出现变化从而反映疗效,时间较长.为了能够尽早评价疗效,及早指导下一步治疗,核磁共振弥散加权成像(DWI)近年来成为研究热点.下面将对其在恶性肿瘤疗效评价中的应用作一综述.     

磁共振弥散加权成像结合常规序列在食管癌显示及术前分期中的应用

目的探讨磁共振弥散加权成像(DWI)结合常规序列对食管癌诊断及其在术前T分期中的临床应用价值。方法对30例被消化道内镜确诊为食管癌患者做常规MRI序列和DWI横断面扫描,b=500、800、1 000 s/mm2,然后分别计算其表观弥散系数值。在DWI结合常规序列图像上测量病变的长度,并与食管钡餐检查、CT、常规T2WI及手术切除病理大体标本的病变长度进行比较。结果所有食管癌病灶在MR-DWI上都是表现为高信号,且明显高于正常食管壁。随着b值增大,病灶的ADC值是逐渐减小的。MR-DWI结合常规序列显示的病变长度与病理结果显示的长度无统计学差异(P=0.955)且有着较高的相关性,与病理大体标本显示病变长度间的相关系数达到0.999,优于食管钡餐检查(r=0.858)、CT(r=0.971)和常规T2WI(r=0.985)。MR-DWI结合常规序列对于食管癌术前T3和T4期诊断准确率分别为85.71%和86.67%,优于常规MRI序列和CT检查,而对T1~2期诊断准确率仅为33.33%。结论 DWI结合常规序列在食管癌的诊断及T分期中具有一定的临床价值,可以为临床提供更多的影像学信息。     

磁共振PWI联合DWI在老年急性期脑梗死中的应用价值

目的 探讨灌注加权成像(PWI)联合弥散加权成像(DWI)对急性期脑梗死的诊断价值.方法 采用回顾性研究方法,收集56例发病时间1～72 h(其中20例为超急性期脑梗死,发病时间＜6 h;36例为急性期脑梗死,发病时间7～72 h)的老年脑梗死病人的临床及影像资料.所有病人均进行PWI和DWI检查,主要观察指标:患侧脑...     

磁共振弥散张量成像在脑梗死诊断中的价值

目的分析脑梗死患者磁共振弥散张量成像(DTI)的特点,探讨DTI在不同时期对脑梗死患者诊断的价值。方法分别对40例不同时期脑梗死患者和40名健康志愿者行MR I检查,包括T1、T2加权成像、弥散加权成像及DTI,重建部分各向异性(FA)图,对梗死区、健侧相应部位及正常对照组相应部位进行FA值、表观弥散系数(ADC)值测量。结果①DTI显示的梗死灶范围较常规MR I成像更加准确、清晰。②脑梗死组患者梗死区及梗死同侧内囊后肢、大脑脚、皮质脊髓束的FA值分别为0.12±0.01、0.29±0.03、0.36±0.12及0.35±0.04,低于对侧相应部位的0.35±0.08、0.50±0.13、0.53±0.14、0.56±0.07,差异均具有显著性(P<0.05);脑梗死患者健侧ADC、FA值与正常对照组相应部位对比,差异无显著性(P>0.05)。③脑梗死后脑组织FA值、ADC值随梗死时间呈一定规律性变化,在超早期患侧FA值较对侧无一致性变化,可轻度升高或轻度降低,随后(急性期、亚急性期、慢性期)降低;患侧ADC值随梗死时间延长呈明显减低、逐渐恢复正常、继而又升高的规律。结论DTI检查有助于明确脑梗死是否累及白质纤维束,ADC值与FA值联合能更精确对脑梗死进行临床分期和定位。     

Deep-tissue anatomical imaging of mice using carbon nanotube fluorophores in the second near-infrared window

Fluorescent imaging in the second near-infrared window (NIR II, 1-1.4 μm) holds much promise due to minimal autofluorescence and tissue scattering. Here, using well-functionalized biocompatible single-walled carbon nanotubes (SWNTs) as NIR II fluorescent imaging agents, we performed high-frame-rate video imaging of mice during intravenous injection of SWNTs and investigated the path of SWNTs through the mouse anatomy. We observed in real-time SWNT circulation through the lungs and kidneys several seconds postinjection, and spleen and liver at slightly later time points. Dynamic contrast-enhanced imaging through principal component analysis (PCA) was performed and found to greatly increase the anatomical resolution of organs as a function of time postinjection. Importantly, PCA was able to discriminate organs such as the pancreas, which could not be resolved from real-time raw images. Tissue phantom studies were performed to compare imaging in the NIR II region to the traditional NIR I biological transparency window (700-900 nm). Examination of the feature sizes of a common NIR I dye (indocyanine green) showed a more rapid loss of feature contrast and integrity with increasing feature depth as compared to SWNTs in the NIR II region. The effects of increased scattering in the NIR I versus NIR II region were confirmed by Monte Carlo simulation. In vivo fluorescence imaging in the NIR II region combined with PCA analysis may represent a powerful approach to high-resolution optical imaging through deep tissues, useful for a wide range of applications from biomedical research to disease diagnostics.     

Two-Photon Time-Gated In Vivo Imaging of Dihydrolipoic-Acid-Decorated Gold Nanoclusters

Due to the unique advantages of two-photon technology and time-resolved imaging technology in the biomedical field, attention has been paid to them. Gold clusters possess excellent physicochemical properties and low biotoxicity, which make them greatly advantageous in biological imaging, especially for in vivo animal imaging. A gold nanocluster was coupled with dihydrolipoic acid to obtain a functionalized nanoprobe; the material displayed significant features, including a large two-photon absorption cross-section (up to 1.59 × 10⁵ GM) and prolonged fluorescence lifetime (>300 ns). The two-photon and time-resolution techniques were used to perform cell imaging and in vivo imaging.     

颅内出血的磁共振成像

MRI的常规序列T1加权成像、T2加权成像和液体衰减反转恢复(FLAIR)序列均可敏感地检出亚急性期和慢性期颅内出血;梯度回波成像可检出各期颅内出血,但血肿信号强度与血肿存在的时间无相关性。弥散加权成像和表观弥散系数能提供更多有关血肿中心区、周围区和梗死后出血的信息。     

Comparative studies of angioscopy and ultrasound for the evaluation of arterial disease

In this in vitro investigation, we studied the histopathological basis for intravascular ultrasound image interpretation and how this technique compares with fiberoptic angioscopy in assessing atherosclerosis. This article presents the sensitivity and specificity of these techniques in the recognition of arterial abnormalities. The relevance of these data in interventional therapeutic procedures and the clinical implications of intravascular imaging methods are also discussed.     

Simultaneous in vivo positron emission tomography and magnetic resonance imaging

Positron emission tomography (PET) and magnetic resonance imaging (MRI) are widely used in vivo imaging technologies with both clinical and biomedical research applications. The strengths of MRI include high-resolution, high-contrast morphologic imaging of soft tissues; the ability to image physiologic parameters such as diffusion and changes in oxygenation level resulting from neuronal stimulation; and the measurement of metabolites using chemical shift imaging. PET images the distribution of biologically targeted radiotracers with high sensitivity, but images generally lack anatomic context and are of lower spatial resolution. Integration of these technologies permits the acquisition of temporally correlated data showing the distribution of PET radiotracers and MRI contrast agents or MR-detectable metabolites, with registration to the underlying anatomy. An MRI-compatible PET scanner has been built for biomedical research applications that allows data from both modalities to be acquired simultaneously. Experiments demonstrate no effect of the MRI system on the spatial resolution of the PET system and <10% reduction in the fraction of radioactive decay events detected by the PET scanner inside the MRI. The signal-to-noise ratio and uniformity of the MR images, with the exception of one particular pulse sequence, were little affected by the presence of the PET scanner. In vivo simultaneous PET and MRI studies were performed in mice. Proof-of-principle in vivo MR spectroscopy and functional MRI experiments were also demonstrated with the combined scanner.     

An imaging spectroscopy approach for measurement of oxygen saturation and hematocrit during intravital microscopy

OBJECTIVE: Oxygen supply and partial pressure are key determinants of tissue metabolic status and are also regulators of vascular function including production of reactive oxygen species, vascular remodeling, and angiogenesis. The objective of this study was to develop an approach for the determination of oxygen saturation and hematocrit for individual microvessels in trans- and epi-illumination intravital microscopy. METHODS: A spectral approach was used, taking advantage of the availability of commercial imaging systems that allow digital recording of intravital images at a number of predetermined wavelengths within a relatively short time. The dependence of validity and precision of saturation measurements on critical experimental variables (reference spectra, number and selection of wavelengths, exposure time, analysis area, analysis model) was evaluated. In addition, a software approach for two-dimensional analysis of images was developed. RESULTS: Exposure times per wavelength of about 200 ms and use of up to 50 wavelengths evenly spaced from 500 to 598 nm allow automatic discrimination of microvessels from tissue background (segmentation) with reliable determination of oxygen saturation (in trans- and epi-illumination) and hematocrit (in transillumination). CONCLUSIONS: The present imaging spectroscopy approach allows detailed assessment of oxygen transport and other functional parameters at the microcirculatory level.     

胰腺癌影像诊断新进展

目前,胰腺癌的早期诊断受到关注.传统影像诊断技术有CT、MR和超声.新的技术已经发展起来,比如PET/CT融合和MRS,尤其是分子影像的实验研究,为今后胰腺癌的早期诊断提供新的技术手段.     

Contrast-enhanced ultrasonographic imaging diagnosis on assessment of vascularity in liver metastatic lesions

AIM: To investigate the vasculature of rabbit liver metastatic lesions by color Doppler imaging and power Doppler imaging (PDI) techniques. METHODS: Eight New Zealand rabbits with implanted VX2 liver tumors were used. All ultrasound examinations were performed with a HP 5500 color Doppler ultrasound scanner. Before and after the injection of contrast agent, the changes of gray scale and the periphery and intralesional blood flow of the liver metastatic lesion were carefully observed by B mode ultrasound, color Doppler flow imaging (CDFI) and PDI. RESULTS: Twelve lesions were found in the eight rabbits with implanted VX2 liver tumors, whose diameter ranged from 1.6 to 4.8 cm. Echoes of these lesions were not characterized and has lack of specificity. After the injection of contrast agent, the numbers of dot or strip-like flow messages increased both at the periphery and inside of these lesions under the mode of CDFI and PDI, and were more pronounced under PDI. Morphology of intralesional vessels extended, even branched and some signals were clearly found encircling the lesion. And some vessels were found penetrating into the center of the lesion. CONCLUSION: PDI after injection of self-made echo contrast agent can show a pronounced sensitivity than that of B mode ultrasound and CDFI in diagnosis of vascularity of a metastatic lesion.