Depth profiling of calcifications in breast tissue using picosecond Kerr-gated Raman spectroscopy

Breast calcifications are found in both benign and malignant lesions and their composition can indicate the disease state. Calcium oxalate (dihydrate) (COD) is associated with benign lesions, however calcium hydroxyapatite (HAP) is found mainly in proliferative lesions including carcinoma. The diagnostic practices of mammography and histopathology examine the morphology of the specimen. They can not reliably distinguish between the two types of calcification, which may indicate the presence of a cancerous lesion during mammography. We demonstrate for the first time that Kerr-gated Raman spectroscopy is capable of non-destructive probing of sufficient biochemical information from calcifications buried within tissue, and this information can potentially be used as a first step in identifying the type of lesion. The method uses a picosecond pulsed laser combined with fast temporal gating of Raman scattered light to enable spectra to be collected from a specific depth within scattering media by collecting signals emerging from the sample at a given time delay following the laser pulse. Spectra characteristic of both HAP and COD were obtained at depths of up to 0.96 mm, in both chicken breast and fatty tissue; and normal and cancerous human breast by utilising different time delays. This presents great potential for the use of Raman spectroscopy as an adjunct to mammography in the early diagnosis of breast cancer.     

Towards a safe non-invasive method for evaluating the carbonate substitution levels of hydroxyapatite (HAP) in micro-calcifications found in breast tissue

A new diagnostic concept based on deep Raman spectroscopy is proposed permitting the non-invasive determination of the level of carbonate substitution in type II calcifications (HAP). The carbonate substitution has shown to be directly associated with the pathology of the surrounding breast tissue and different pathology groups can therefore be separated using specific features in the Raman spectra of the calcifications. This study explores the principle of distinguishing between type II calcifications, found in proliferating lesions, by using the strongest Raman peak from calcium hydroxyapatites (the phosphate peak at 960 cm(-1)) to act as a surrogate marker for carbonate substitution levels. It is believed that carbonate ion substitution leads to a perturbation of the hydroxyapatite lattice which in turn affects the phosphate vibrational modes. By studying calcifications, with known carbonate content, buried in porcine tissue it has been possible to evaluate the feasibility of using the proposed approach to probe the composition of the calcifications in vivo and hence provide pathology specific information non-invasively, in real time. Using the proposed concept we were able to determine the level of carbonate substitutions through soft tissue phantom samples (total thickness of 5.6 mm). As the level of carbonate substitution has been previously correlated with mid-FTIR to the lesion type, i.e. whether benign or invasive or in situ carcinoma, the new findings provide a major step forward towards establishing a new capability for diagnosing benign and malignant lesions in breast tissue in a safe and non-invasive manner in vivo.     

Characterization of genuine and fake artesunate anti-malarial tablets using Fourier transform infrared imaging and spatially offset Raman spectroscopy through blister packs

In support of the efforts to combat the illegal sale and distribution of counterfeit anti-malarial drugs, we evaluated a new analytical approach for the characterization and fast screening of fake and genuine artesunate tablets using a combination of Raman spectroscopy, Spatially Offset Raman Spectroscopy (SORS) and Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) imaging. Vibrational spectroscopy provided chemically specific information on the composition of the tablets; the complementary nature of Raman scattering and FTIR imaging allowed the characterization of both the overall and surface composition of the tablets. The depth-resolving power of the SORS approach provided chemically specific information on the overall composition of the tablets, non-invasively, through a variety of packaging types. Spatial imaging of the tablet surface (using ATR-FTIR) identified the location of domains of excipients and active ingredients with high sensitivity and enhanced spatial resolution. The advantages provided by a combination of SORS and ATR-FTIR imaging in this context confirm its potential for inclusion in the analytical protocol for forensic investigation of counterfeit medicines.     

3.0T MRI检查结合X线钼靶诊断乳腺恶性肿瘤的研究

本研究探讨3.0T磁共振成像(MRI)结合X线钼靶诊断乳腺恶性肿瘤的价值。采用回顾性研究方法,选取乳腺肿块患者110例162个病灶,给予3.0T MRI及X线钼靶检查。经病理确诊为恶性病变101个;恶性病灶形态不规则、边缘毛刺、时间-信号强度曲线(TIC)类型Ⅲ型和早期增强率≥60%比例明显高于良性病灶(P<0.05),而分叶状比例和表观扩散系数(ADC)值明显低于良性病变(P<0.05);恶性病变X线钼靶表现:形态不规则、钙化、结构不对称和大导管征比例明显高于良性病变(P<0.05);MRI联合X线钼靶诊断乳腺恶性病变的灵敏性、准确性和阴性预测值明显高于MRI诊断(P<0.05)。3.0T MRI检查结合X线钼靶诊断乳腺恶性肿瘤有较好的价值。     

基于稳健统计的新鲜乳腺组织拉曼光谱分析

采用便携式拉曼光谱仪对新鲜乳腺正常组织、良性组织和恶性组织进行检测,通过稳健统计方法对拉曼光谱数据进行分析处理,建立乳腺组织拉曼光谱标准图谱,根据标准图谱特征峰归纳3类组织的主要区别和特征.在3类乳腺组织中,正常组织有明显的脂类特征峰(1078,1297,1437,1653,1746 cm-1),而在良性和恶性组织中则出现了较明显的蛋白特征峰(1259,1530,1650 cm-1),正常、良性和恶性组织的主要区别集中在1340和1534 cm-1处,应归属为蛋白和类胡萝卜素,这一结果并不能由经典统计方法得出.基于稳健统计建立的新鲜乳腺组织拉曼光谱标准图谱为构建数学模型来鉴别乳腺病灶的性质奠定了基础.     

Time-resolved spatially offset Raman spectroscopy for depth analysis of diffusely scattering layers

The objective of this study is to use time-resolved (TR) Raman spectroscopy, spatially offset Raman spectroscopy (SORS), and a combination of these approaches to obtain high quality Raman spectra from materials hidden underneath an opaque layer. Both TR Raman and SORS are advanced techniques that allow for an increased relative selectivity of photons from deeper layers within a sample. Time-resolved detection reduces fluorescence background, and the selectivity for the second layer is improved. By combining this with spatially offset excitation we additionally increased selectivity for deeper layers. Test samples were opaque white polymer blocks of several mm thicknesses. Excitation was carried out with a frequency-doubled Ti:sapphire laser at 460 nm, 3 ps pulse width and 76 MHz repetition rate. Detection was either with a continuous-wave CCD camera or in time-resolved mode using an intensified CCD camera with a 250 ps gate width. The Raman photons were collected in backscatter mode, with or without lateral offset. By measuring the delay of the Raman signal from the second layer (polyethylene terephthalate/PET/Arnite), the net photon migration speeds through Teflon, polythene, Delrin and Nylon were determined. Raman spectra could be obtained from a second layer of PET through Teflon layers up to 7 mm of thickness. The ability to obtain chemical information through layers of diffusely scattering materials has powerful potential for biomedical applications.     

Raman Spectroscopy and Fluorescence Photon Migration for Breast Cancer Diagnosis and Imaging

We are developing optical methods based on near infra-red Raman spectroscopy and fluorescence photon migration for diagnosis and localization of breast cancer. We demonstrate the ability of Raman spectroscopy to classify accurately normal, benign and malignant breast tissues, an important step in developing Raman spectroscopic needle probes as a tool for improving the accuracy of needle biopsy. We also show that photon migration imaging can be used to localize accurately small fluorescent objects imbedded in a thick turbid medium with realistic optical properties, thus demonstrating the potential of this technique for optical imaging.     

MRI增强扫描联合DWI检测在乳腺癌诊断中的应用

本文探究了MRI增强扫描(DCE-MRI)联合磁共振扩散加权成像(DWI)检测对乳腺癌的诊断效果。回顾性分析2015年8月~2017年8月本院收治的经手术病理证实的乳腺癌患者81例,术前均行DCE-MRI和DWI检查,根据数据绘制时间-信号强度曲线(TIC),并计算扩散系数(ADC)值。以病理结果为金标准,计算单一检测及联合检测的诊断准确率,并采用ROC分析ADC值诊断乳腺癌良/恶性的效能。结果显示,81例患者经手术病理诊断显示良性37例、恶性44例;DCE-MRI与DWI联合检测的敏感度与准确度显著高于单一检测(P<0.05);良、恶性病灶的TIC分型分布比较,差异具有统计学意义(P<0.05);恶性病灶ADC值较良性病灶低(P<0.05);ADC值诊断乳腺癌良/恶性最佳界限值为1.28×10-3 mm 2/s,灵敏度和特异度分别为86.5%和90.9%。因此,DCE-MRI与DWI联合检测可明显提高乳腺癌良/恶性病变诊断的准确度,为临床诊断提供可靠影像学依据。     

Short-wave infrared excited spatially offset Raman spectroscopy (SORS) for through-barrier detection

Spatially offset Raman spectroscopy (SORS) using 1064 nm excitation is demonstrated here to detect chemicals through a physical barrier such as a container. This excitation wavelength overcomes the issue of fluorescence from the target chemical, whilst retaining the benefits of the SORS technique for through-barrier detection. These advantages have a wide range of applications in both civilian and military environments.     

Raman microscopy for the chemometric analysis of tumor cells

Raman spectroscopy is recognized as a tool for chemometric analysis of biological materials due to the high information content relating to specific physical and chemical qualities of the sample. Thirty cells belonging to two different prostatic cell lines, PNT1A (immortalized normal prostate cell line) and LNCaP (malignant cell line derived from prostate metastases), were mapped using Raman microscopy. A range of spectral preprocessing methods (partial least-squares discriminant analyses (PLSDAs), principal component analyses (PCAs), and adjacent band ratios (ABRs)) were compared for input into linear discriminant analysis to model and classify the two cell lines. PLSDA and ABR were able to correctly classify 100% of cells into benign and malignant groups, while PLSDA correctly classified a greater proportion of individual spectra. PCA was used to image the distribution of various biochemicals inside each cell and confirm differences in composition/distribution between benign and malignant cell lines. This study has demonstrated that PLSDAs and ABRs of Raman data can identify subtle differences between benign and malignant prostatic cells in vitro.     

超声弹性成像联合BI-RADS对微小(≤2cm)乳腺良恶性病变的鉴别价值

本文对超声弹性成像（UE）联合乳腺影像报告和数据系统（BI-RADS）对微小（≤2 cm）乳腺良恶性病变的鉴别价值进行了分析。研究对象选取2018年3月~2019年3月期间本院80例乳腺病变患者共112个病灶,所有患者均给予UE和BI-RADS检查,以病理检查为参照,分析UE、BI-RADS及二者联合对微小（≤2 cm）乳腺良恶性病变的鉴别价值。病理检查结果显示,112个病灶中,良性60个（53.57%）、恶性52个（46.43%）;恶性乳腺病变患者UE和BI-RADS评分明显高于良性患者,差异有统计学意义（P<0.05）。UE鉴别微小乳腺良恶性病变（≤2 cm）的敏感度为76.92%、特异度为76.67%、准确度为76.79%,BI-RADS的敏感度为80.77%、特异度为80.00%、准确度为80.36%,UE联合BI-RADS的敏感度、特异度、准确度分别为96.15%、95.00%、95.54%,可见UE联合BI-RADS的鉴别效果明显优异,差异有统计学意义（P<0.05）。本文证实了UE、BI-RADS对微小（≤2 cm）乳腺良恶性病变具有良好的鉴别价值,且二者联合的鉴别价值更高。     

Raman endoscopy for in vivo differentiation between benign and malignant ulcers in the stomach

The aim of this study was to evaluate the clinical utility of an image-guided Raman endoscopy technique for in vivo differential diagnosis of benign and malignant ulcerous lesions in the stomach. A rapid-acquisition image-guided Raman endoscopy system with 785 nm laser excitation has been developed to acquire in vivo gastric tissue Raman spectra within 0.5 s during clinical gastroscopic examinations. A total of 1102 in vivo Raman spectra were acquired from 71 gastric patients, in which 924 Raman spectra were from normal tissue, 111 Raman spectra were from benign ulcers whereas 67 Raman spectra were from ulcerated adenocarcinoma. There were distinctive spectral differences in Raman spectra among normal mucosa, benign ulcers and malignant ulcers, particularly in the spectral ranges of 800-900, 1000-1100, 1245-1335, 1440-1450 and 1500-1800 cm(-1), which primarily contain signals related to proteins, DNA, lipids and blood. The malignant ulcerous lesions showed Raman signals to be mainly associated with abnormal nuclear activity and decrease in lipids as compared to benign ulcers. Partial least squares-discriminant analysis (PLS-DA) was employed to generate multi-class diagnostic algorithms for classification of Raman spectra of different gastric tissue types. The PLS-DA algorithms together with leave-one tissue site-out, cross validation technique yielded diagnostic sensitivities of 90.8%, 84.7%, 82.1%, and specificities of 93.8%, 94.5%, 95.3%, respectively, for classification of normal mucosa, benign and malignant ulcerous lesions in the stomach. This work demonstrates that image-guided Raman endoscopy technique associated with PLS-DA diagnostic algorithms has for the first time promising clinical potential for rapid, in vivo diagnosis and detection of malignant ulcerous gastric lesions at the molecular level.     

Application of scanning electron microscopy and X-ray microanalysis: FE-SEM, ESEM-EDS, and EDS mapping for studying the characteristics of topographical microstructure and elemental mapping of human cardiac calcified deposition

To explore the pathogenic mineral formation in a huge cardiolith isolated from the left heart atrium of an 80-year-old male patient, field emission scanning electron microscopy (FE-SEM) was used to analyze the topographic microstructure and perform elemental mapping in a cross-section of the cardiac calcified deposit after dissection. Environmental SEM equipped with an energy dispersive X-ray spectrometer (EDS) was also used to investigate the composition and spatial distribution of elements in the cross-section, and fiberoptic Raman spectroscopy was used to reidentify the chemical composition of designated positions. The results indicated that calcium hydroxyapatite and cholesterol were the main components of the cardiac calculus. The plate-like structures of calcium hydroxyapatite were unevenly spread over the cholesterol of the cardiac calculus. The calcium hydroxyapatite-rich area exhibited higher amounts of C, O, P, and Ca elements as well as trace amounts of N, Na, Mg, and Al, whereas the major concentration of C, minor concentrations of N and O, and trace amounts of P and Ca were observed in the cholesterol-rich area. Hypercholesterolemia associated with calcification of this cardiac calculus was proposed. Both FE-SEM and ESEM energy dispersive X-ray microanalyses were performed directly, for the first time, to provide useful information on the microstructural characteristics and spatial distribution of elements on the surface of human cardiac calculi.

Distinctive Molecular Abnormalities in Benign and Malignant Skin Lesions: Studies by Raman Spectroscopy

Abstract— Near-infrared Fourier transform Raman spectroscopy is an analytical, nondestructive technique that provides information about the molecular structure of the investigated sample. The molecular structure of proteins and lipids differs between neoplastic and normal tissues and therefore Raman spectroscopy has been considered promising for the diagnosis of cancer. We aimed to compare the molecular structure of normal skin, benign and malignant skin lesions by the near-infrared Fourier transform Raman spectroscopy. Biopsies were obtained from the following skin lesions: skin tag, dermatofibroma, seborrhoeic keratosis, actinic keratosis, keratoacan-thoma, basal cell carcinoma, squamous cell carcinoma, nevus intradermal, nevus compositus, dysplastic nevus and lentigo maligna. Control skin was harvested from the vicinity of these lesions. In the Raman spectra, the secondary structure of the proteins was reflected by the amide vibrations of peptide bonds. The principal lipid vibrations were twisting and wagging (CH₂) and CH stretching vibrations. Histologically distinguishable lesions showed specific combinations of band changes indicating alterations in the protein conformation and in the molecular structure of the lipids. Histogenetically related lesions (actinic keratosis and sqamous cell carcinoma) produced similar but not identical patterns of spectral changes. Because the examined skin lesions produced reproducible and unique spectra, we suggest that Raman spectroscopy will be useful for diagnosis of skin lesions.     

二维超声联合超声造影TIC参数在乳腺导管内病变良/恶性诊断中的应用价值

本研究分析了二维超声(2DUS)联合超声造影(CEUS)时间-强度曲线(TIC)参数在乳腺导管内病变良/恶性鉴别诊断中的应用价值.选取乳腺导管内病变患者81例(共93个病变),均行2DUS及CEUS检查.结果显示,2DUS检出恶性病变17个,良性病变48个,诊断准确度69.89％(65/93)、敏感度53.13％(17...     

CEUS联合常规超声诊断乳腺非肿块型疾病的研究

本文探讨超声造影(CEUS)联合常规超声在乳腺非肿块型疾病良恶性鉴别中的应用价值。回顾性分析68例乳腺非肿块型病变患者的影像资料,以病理结果为金标准,对比分析常规超声、CEUS及两者联合的诊断价值。68例乳腺非肿块型病变中良性28例,恶性40例;常规超声特征中,良恶性病灶在微钙化、病灶周围血流分布方面差异有统计学意义(P<0.05);CEUS中良恶性病灶在增强强度、均匀度、显影时间及穿支血管方面差异均有统计学意义(P<0.05),TIC定量参数中,良恶性病灶在TTP、PI、AUC方面差异有统计学意义。常规超声联合CEUS诊断乳腺非肿块型疾病良恶性敏感度、特异度、准确度、阳性预测值及阴性预测值分别为:90.00%、96.43%、92.65%、97.30%、87.10%,高于单独使用常规超声或CEUS(P<0.05)。CEUS联合常规超声可显著提高乳腺非肿块型疾病良恶性的诊断效能,具有较好的临床应用价值。     

超声BI-RADS联合CT对≤2 cm乳腺良恶性病变的鉴别价值

本文研究超声乳腺影像报告和数据系统(BI-RADS)联合计算机断层扫描(CT)对≤2 cm乳腺良恶性病变的鉴别价值.以≤2 cm乳腺病变患者184例为研究对象,所有患者均给予超声、CT检查,以病理学结果为对照,分析超声BI-RADS、CT及二者联合对≤2 cm乳腺良恶性病变的鉴别价值.病理学结果显示,乳腺癌有58例(3...     

BSA-羟基磷灰石可溶性复合物的FTIR光谱

利用富立叶变换红外光谱对水溶性牛血清白蛋白(BSA)羟基磷灰石复合物的组成及结构进行了研究.结果表明,其组成具有非化学计量的性质,且复合物中BSA与羟基磷灰石间存在相互作用.从而增加了羟基磷灰石在水中的溶解度.正是由于羟基磷灰石与蛋白质形成了水溶性的复合物,使羟基磷灰石在蛋白质结构的基质上成核和自组装成为可能,从而引起和促进了生物矿化过程.     

A biospectroscopic interrogation of fine needle aspirates points towards segregation between graded categories: an initial study towards diagnostic screening

Fine needle aspirates (FNAs) of suspicious breast lesions are often used to aid the diagnosis of female breast cancer. Biospectroscopy tools facilitate the acquisition of a biochemical cell fingerprint representative of chemical bonds present in a biological sample. The mid-infrared (IR; 4,000–400 cm⁻¹) is absorbed by the chemical bonds present, allowing one to derive an absorbance spectrum. Complementary to IR spectroscopy, Raman spectroscopy measures the scattering by chemical bonds following excitation by a laser to generate an intensity spectrum. Our objective was to apply these methods to determine whether a biospectroscopy approach could objectively segregate different categories of FNAs. FNAs of breast tissue were collected (n = 48) in a preservative solution and graded into categories by a cytologist as C1 (non-diagnostic), C2 (benign), C3 (suspicious, probably benign) or C5 (malignant) [or C4 (suspicious, probably malignant); no samples falling within this category were identified during the collection period of the study]. Following washing, the cellular material was transferred onto BaF₂ (IR-transparent) slides for interrogation by Raman or Fourier-transform IR (FTIR) microspectroscopy. In some cases where sufficient material was obtained, this was transferred to low-E (IR-reflective) glass slides for attenuated total reflection–FTIR spectroscopy. The spectral datasets produced from these techniques required multivariate analysis for data handling. Principal component analysis followed by linear discriminant analysis was performed independently on each of the spectral datasets for only C2, C3 and C5. The resulting scores plots revealed a marked overlap of C2 with C3 and C5, although the latter pair were both significantly segregated (P < 0.001) in the Raman spectra. Good separation was observed between C3 and C5 in all three spectral datasets. Analysis performed on the average spectra showed the presence of three distinct cytological groups. Our findings suggest that biospectroscopy tools coupled with multivariate analysis may support the current FNA tests whilst increasing the sensitivity and associated reliability for improved diagnostics.     

Quantitative histochemical analysis of human artery using Raman spectroscopy.

We have developed a method for using near infrared Raman spectroscopy to quantitatively analyze the histochemical composition of human artery. The main contributors to bands observed in the Raman spectra of normal and atherosclerotic aorta are the proteins collagen and elastin, cholesterol lipids, and calcium hydroxyapatite. The Raman scattering cross-sections of different bands for these components have been determined in order to understand their relative contributions to the Raman spectra of biological tissue. The Raman signal is observed to behave linearly with the concentration of the components, even in a highly scattering medium such as a powder. Using these data, we have developed a linear model that can be used to extract the quantitative contribution of an individual component to the spectrum of a mixture. The model has been applied to several mixtures of known composition of tissue constituents in order to evaluate its precision and accuracy. The calculated fit coefficients from the spectra are in agreement with the measured values within experimental uncertainties. The spectra of different types of atherosclerotic aorta have also been modeled, and we have extracted quantitative information regarding the relative concentration of biological constituents in atherosclerotic aorta.