乳腺脂肪坏死的钼靶X线诊断

目的：探讨乳腺脂肪坏死的钼靶X线征象，总结其诊断价值。材料与方法：回顾性分析5例经临床和病理证实的乳腺脂肪坏死的钼靶X线平片表现，分析其特点。病人年龄34—68岁，平均年龄49．5岁。结果：3例为局部脂肪层混浊，可见小斑片及点状致密影；1例为结节样改变，边缘毛糙；1例可见病变处乳房皮肤局限性增厚；1例乳头稍内陷，皮肤略呈橘皮样改变。结论：钼靶摄影对乳腺脂肪坏死具有较高的诊断价值。     

乳腺脂肪坏死的X线诊断

目的 评价乳腺脂肪坏死的X线征象及其病理学基础。方法 回顾性分析14例经病理证实的乳腺脂肪坏死的X线平片,对其中2例活检的病人进行了短期随访。结果 主要X线征象：（1）油脂性囊肿5例,其中2例伴囊壁钙化。（2）不对称性密度增加6例。（3）不规则肿块3例。 14例中8例伴有病灶周围结构紊乱。2例随病灶均无明显变化。结论 乳腺不死的X线表现与其病灶内纤维结缔组织的反应强度有关,在多种多样的X线表现中油脂性囊肿是特异性的X线表现。     

乳腺脂肪坏死的X线表现

目的探讨乳腺脂肪坏死影像学表现。方法9例病理证实的乳腺脂肪坏死病例,均有钼靶片,3例行CT检查,对其影像学表现进行回顾性分析。结果7例腺体外型表现为:随机分布纤维条索影和小结节样高密度影与脂肪密度影混杂存在;2例腺体内型表现为:规则和不规则肿物影。结论影像学检查较临床检查在鉴别脂肪坏死和乳腺癌方面更有价值。随机分布纤维条索影和小结节样高密度影与脂肪密度影混杂存在是乳腺脂肪坏死的典型表现。     

乳腺脂肪坏死的X线和超声诊断

目的探讨乳腺脂肪坏死的X线及B超表现，提高对本病影像诊断的认识。资料与方法回顾性分析25例经手术、病理证实的乳腺脂肪坏死X线平片及超声声像图表现。结果X线片表现：(1)双侧乳腺结构、密度不对称10例；(2)淡薄片影3例；(3)有毛刺的结节5例；(4)X线片无阳性发现5例。超声声像图表现：(1)16例(16／17，94．1％)非医源性脂肪坏死病灶位于皮下脂肪层；(2)结节回声高低不一(高、低、无)；(3)彩色Doppler超声病灶无血流信号8例。结论乳腺脂肪坏死根据其病因和时期，其影像表现多种多样。X线与B超检查结合，本组有65％可排除乳腺癌的诊断。位于乳腺脂肪层内的网状片影或有毛刺的结节首先考虑脂肪坏死的可能，紧密结合临床病史，可提高本病诊断准确性。     

乳腺脂肪坏死的X线表现及病理对照研究

目的 探讨乳腺脂肪坏死的X线表现及病理基础，提高对脂肪坏死的认识。方法 回顾性分析经手术、病理证实的91例（其中2例为双侧乳腺脂肪坏死，共93个病变。）脂肪坏死X线表现，并与病理结果对照。结果 主要X线表现：（1）无任何异常X线发现14例（15．4％）；（2）脂性囊肿6例（6．6％）；（3）表现为肿物20例（22．0％），其中1例为双侧乳腺脂肪坏死；（4）表现为小结节13例（14．3％）；（5）脂肪层内星芒影、斑片影、索条影混杂出现28例（30．8％），其中1例为双侧乳腺脂肪坏死；（6）脂肪层内索条影交织呈网状5例（5．5％）；（7）结构不良者5例（5．5％）。分布部位：（1）位于脂肪层内55例；（2）向脂肪层突出或位于脂肪层与腺体交界处13例，常规位摄片位于脂肪层与腺体交界处的脂肪坏死，切线位投照有利于将病变显示于脂肪层内；（3）位于腺体之间9例；（4）乳腺平片未见异常发现14例。病理表现：（1）脂性囊肿是病变早期的特征性X线表现。（2）脂肪层内不均匀密度肿物影或小结节影为病变中期的特征性表现，反应了纤维组织逐渐替代了液化坏死的脂肪组织。（3）脂肪层内或浅层腺体内局限星芒状致密影以及不规则的网状影最常见，是病变后期的特征性表现。反应了坏死脂肪组织被吸收，周围残留部分纤维组织。通常不同病理时期的X线表现常同时出现。结论 乳腺X线摄影对于脂肪坏死具有重要诊断价值。     

乳腺脂肪坏死的X线表现与鉴别诊断

目的:探讨乳腺脂肪坏死的X线诊断及其鉴别诊断,提高脂肪坏死的认识,减少误诊。方法:回顾性分析58例经病理证实的乳腺脂肪坏死的X线表现。结果:乳腺脂肪坏死根据其病因及时期X线表现多种多样:①无任何阳性X线表现9例;②脂性囊肿5例;③肿物11例;④结节2例;⑤不对称致密4例;⑥斑片影5例;⑦脂肪层内星芒状、索条状、网状影18例;⑧结构扭曲2例;⑨颗粒状、片状不规则钙化、多形性钙化2例。在多种多样的X线表现中,腺体内的脂性囊肿及皮下脂肪层内的局限星芒状、索条状、不规则网状影为脂肪坏死的特征性表现。结论:乳腺X线检查对脂肪坏死具有重要的诊断价值。认真询问病史(如外伤、手术及炎症史等),对本病有重要帮助。     

乳腺分泌性疾病的X线诊断(附24例报道)

本文回顾分析了24例乳腺分泌性疾病,其中积乳囊肿9例、浆细胞性乳腺炎10例、脂肪坏死5例。积乳囊肿分成四型:浸润型、致密型、透亮型及混合型。对浆细胞性乳腺炎及脂肪坏死的X线表现重点进行了描述,认为浆细胞性乳腺炎及脂肪坏死临床虽类似癌肿,但X线像上仍具有一定的特征。本组有约50％的病人术前获得诊断。     

乳腺叶状囊肉瘤临床钼钯X线与彩超征象分析

目的：结合文献资料分析总结乳腺叶状囊肉瘤的临床特点、钼钯X线与彩色多谱勒超声影像征象。方法：随机搜集临床资料完整的乳腺叶状囊肉瘤7例，每例患者均接受钼钯X线与彩色多谱勒超声检查，所有病例均经手术病理证实。结果：叶状囊肉瘤患者病史多较长，病灶体积一般较大，或在短时期内增长迅速。钼钯X线片上病灶多表现为密度均匀、边缘光滑的分叶状肿块。彩色多谱勒超声检查，病灶以不均匀中低回声为主。结论：叶状囊肉瘤多发于40—50岁，患者有较为独特的临床特点，结合钼钯X线与B型超声征象可以作出诊断。     

Identification of brown adipose tissue in mice with fat–water IDEAL‐MRI

Purpose:

To investigate the feasibility of using IDEAL (Iterative Decomposition with Echo Asymmetry and Least squares estimation) fat–water imaging and the resultant fat fraction metric in detecting brown adipose tissue (BAT) in mice, and in differentiating BAT from white adipose tissue (WAT).

Materials and Methods:

Excised WAT and BAT samples and whole‐mice carcasses were imaged with a rapid three‐dimensional fat–water IDEAL‐SPGR sequence on a 3 Tesla scanner using a single‐channel wrist coil. An isotropic voxel size of 0.6 mm was used. Excised samples were also scanned with single‐voxel proton spectroscopy. Fat fraction images from IDEAL were reconstructed online using research software, and regions of WAT and BAT were quantified.

Results:

A broad fat fraction range for BAT was observed (40–80%), in comparison to a tighter and higher WAT range of 90–93%, in both excised tissue samples and in situ. Using the fat fraction metric, the interscapular BAT depot in each carcass could be clearly identified, as well as peri‐renal and inguinal depots that exhibited a mixed BAT and WAT phenotype appearance.

Conclusion:

Due to BAT's multi‐locular fat distribution and extensive mitochondrial, cytoplasm, and vascular supply, its fat content is significantly less than that of WAT. We have demonstrated that the fat fraction metric from IDEAL‐MRI is a sensitive and quantitative approach to noninvasively characterize BAT. J. Magn. Reson. Imaging 2010;31:1195–1202. © 2010 Wiley‐Liss, Inc.     

Unequivocal identification of brown adipose tissue in a human infant

We report the unique depiction of brown adipose tissue (BAT) by magnetic resonance imaging (MRI) and computed tomography (CT) in a human 3-month-old infant. Based on cellular differences between BAT and more lipid-rich white adipose tissue (WAT), chemical-shift MRI and CT were both capable of generating distinct signal contrasts between the two tissues and against surrounding anatomy, utilizing fat-signal fraction metrics in the former and x-ray attenuation values in the latter. While numerous BAT imaging experiments have been performed previously in rodents, the identification of BAT in humans has only recently been described with fusion positron emission and computed tomography in adults. The imaging of BAT in children has not been widely reported and, furthermore, MRI of human BAT in general has not been demonstrated. In the present work, large bilateral supraclavicular BAT depots were clearly visualized with MRI and CT. Tissue identity was subsequently confirmed by histology. BAT has important implications in regulating energy metabolism and nonshivering thermogenesis and has the potential to combat the onset of weight gain and the development of obesity. Current findings suggest that BAT is present in significant amounts in children and that MRI and CT can differentiate BAT from WAT based on intrinsic tissue properties.     

Standardized assessment of whole body adipose tissue topography by MRI

PURPOSE: To assess standardized whole body adipose tissue topography in a cohort of subjects at an increased risk for type 2 diabetes and to compare fat distribution in subgroups regarding anthropometric (age, body mass index [BMI]) and metabolic parameters (insulin sensitivity). MATERIALS AND METHODS: A total of 80 volunteers (40 females, 40 males) underwent T1-weighted MR imaging of the entire body. Standardized adipose tissue (AT) profiles were calculated considering the different body structure of the participants. The measured data were interpolated to a defined number of sampling points enabling a direct comparison of the profiles independent on body structure. Resulting mean profiles and region-dependent standard deviations of four age groups and three BMI-groups were compared for females and males. Correlations between insulin sensitivity and body fat distribution were analyzed. RESULTS: Reliable adipose tissue profiles could be obtained from all volunteers. In BMI-matched subgroups, females show significant higher AT and subcutaneous abdominal AT (P < 0.05 both), but lower visceral AT (P < 0.01) compared to the males. Furthermore, visceral AT increases with age, as shown in the matched age groups. In both gender groups, insulin-resistant subjects are characterized by higher visceral adipose tissue (VAT) compared to insulin-sensitive subjects. In addition, profiles of insulin-resistant subjects show more AT in the shoulder/neck region but less AT in the upper extremities. CONCLUSION: Standardized assessment of whole body AT profiles based on T1-weighted MRI provides a reliable basis for interindividual comparison of the body fat distribution and allows a fast and reliable quantification of total body adipose tissue and the distribution of different AT components as subcutaneous and visceral fat in different body regions. Differences in standardized profiles might enable an early identification of people at risk of metabolic disorders, as not only the amount but also the distribution of AT is expected to play an essential role in the pathogenesis of metabolic diseases.     

Quantification of absolute fat mass using an adipose tissue reference signal model

Purpose

To develop a method for quantifying absolute fat mass, and to demonstrate its feasibility in phantoms and in ex vivo swine specimens at 3 Tesla.

Materials and Methods

Chemical‐shift‐based fat‐water decomposition was used to first reconstruct fat‐only images. Our proposed model used a reference signal from fat in pure adipose tissue to calibrate and normalize the fat signal intensities from the fat‐only images. Fat mass was subsequently computed on a voxel‐by‐voxel basis and summed across each sample. Feasibility of the model was tested in six ex vivo swine samples containing varying mixtures of fat (adipose) and lean tissues. The samples were imaged using 1.5‐mm isotropic voxels and a single‐channel birdcage head coil at 3 Tesla. Lipid assay was independently performed to determine fat mass, and served as the comparison standard.

Results

Absolute fat mass values (in grams) derived by our proposed model were in excellent agreement with lipid assay results, with a 5% to 7% difference (r > 0.99; P < 0.001).

Conclusion

Preliminary results in ex vivo swine samples demonstrated the feasibility of computing absolute fat mass as a quantitative endpoint using chemical‐shift fat‐water MRI with a signal model based on reference fat from pure adipose tissue. J. Magn. Reson. Imaging 2008;28:1483–1491. © 2008 Wiley‐Liss, Inc.     

Automated unsupervised multi‐parametric classification of adipose tissue depots in skeletal muscle

Purpose:

To introduce and validate an automated unsupervised multi‐parametric method for segmentation of the subcutaneous fat and muscle regions to determine subcutaneous adipose tissue (SAT) and intermuscular adipose tissue (IMAT) areas based on data from a quantitative chemical shift‐based water‐fat separation approach.

Materials and Methods:

Unsupervised standard k‐means clustering was used to define sets of similar features (k = 2) within the whole multi‐modal image after the water‐fat separation. The automated image processing chain was composed of three primary stages: tissue, muscle, and bone region segmentation. The algorithm was applied on calf and thigh datasets to compute SAT and IMAT areas and was compared with a manual segmentation.

Results:

The IMAT area using the automatic segmentation had excellent agreement with the IMAT area using the manual segmentation for all the cases in the thigh (R²: 0.96) and for cases with up to moderate IMAT area in the calf (R²: 0.92). The group with the highest grade of muscle fat infiltration in the calf had the highest error in the inner SAT contour calculation.

Conclusion:

The proposed multi‐parametric segmentation approach combined with quantitative water‐fat imaging provides an accurate and reliable method for an automated calculation of the SAT and IMAT areas reducing considerably the total postprocessing time. J. Magn. Reson. Imaging 2013;37:917–927. © 2012 Wiley Periodicals, Inc.     

Accurate segmentation of subcutaneous and intermuscular adipose tissue from MR images of the thigh

Purpose

To describe and evaluate a computer‐assisted method for assessing the quantity and distribution of adipose tissue in thigh by magnetic resonance imaging (MRI).

Materials and Methods

Twenty obese subjects were imaged on a Philips Achieva 1.5T scanner by a fast spin‐echo (FSE) sequence. A total of 636 images were acquired and analyzed by custom‐made software. Thigh subcutaneous adipose tissue (SAT) and bone were identified by fuzzy clustering segmentation and an active contour algorithm. Muscle and intermuscular adipose tissue (IMAT) were assessed by identifying the two peaks of the signal histogram with an expectation maximization algorithm. The whole analysis was performed in an unsupervised manner without the need of any user interaction.

Results

The coefficient of variation (CV) was evaluated between the unsupervised algorithm and manual analysis performed by an expert operator. The CV was low for all measurements (SAT <2%, muscle <1%, IMAT <5%). Limited manual correction of unsupervised segmentation results (less than 10% of contours modified) allowed us to further reduce the CV (SAT <0.5%, muscle <0.5%, IMAT <2%).

Conclusion

The proposed approach allowed effective computer‐assisted analysis of thigh MR images, dramatically reducing the user work compared to manual analysis. It allowed routine assessment of IMAT, a fat‐depot linked with metabolic abnormalities, important in monitoring the effect of nutrition and exercise. J. Magn. Reson. Imaging 2009;29:677–684. © 2009 Wiley‐Liss, Inc.     

Quantitative diffusion imaging of adipose tissue in the human lower leg at 1.5 T

Diffusion‐weighted spin‐echo echo‐planar imaging was developed and applied for assessment of diffusion coefficients of adipose tissue in human lower leg on a 1.5‐T whole‐body MR scanner. Because of the higher molecular weight of triglycerides, apparent diffusion coefficients (ADCs) of adipose tissue are approximately two orders of magnitude smaller compared with water, leading to the necessity of using high b‐values up to 50,000 sec/mm² and an echo time of 240 msec for sufficient diffusion‐related signal attenuation. ADC maps of adipose tissue in the human lower leg were derived for diffusion encoding along orthogonal spatial directions in six healthy volunteers. Mean diffusion coefficients in the tibial bone marrow amounted to (1.81 ± 0.10) × 10^?5 mm²/sec (left–right), (1.96 ± 0.10) × 10^?5 mm²/sec (anterior–posterior), and (1.96 ± 0.20) × 10^?5 mm²/sec (head–feet), respectively. Pixel‐wise calculated ADC values of subcutaneous adipose tissue showed a distinctly higher variation with the smallest ADC values similar to those measured for tibial bone marrow. Some subcutaneous adipose tissue regions showed increased signal attenuation at higher b‐values resulting in ADC coefficients up to 4.2 × 10^?5 mm²/sec. It must be noted that diffusion measurements with extremely high b‐values in vivo are extremely sensitive to incoherent motion effects in tissue. Nonetheless, it could be shown that in vivo diffusion imaging of adipose tissue in human lower leg is possible at 1.5 T in acceptable measurement time of a few minutes. Potential future applications of fat diffusion imaging are seen in temperature measurements in adipose tissue, detection of free fatty acids in white or brown adipose tissue in case of high lipolysis, differentiation of macro‐ and microvesicular steatosis, or assessment of the mobility of intramyocellular lipids. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.     

人脂肪组织NYGGF4基因表达的调控研究

目的探讨肿瘤坏死因子α（TNF-α）、白细胞介素6（IL-6）对肥胖基因NYGGF4表达的调控作用。方法取适量大网膜脂肪组织进行体外培养,分别以10 ng/ml TNF-α和20 ng/ml IL-6干预6、12、24、48、72 h,应用荧光定量RT-PCR技术检测NYGGF4 mRNA表达水平的变化。结果 （1）TNF-α对人脂肪组织NYGGF4 mRNA表达具有明显的上调作用,且具有明显的时间依赖性,呈现随作用时间延长,效应逐渐增加的趋势。（2）IL-6具有降低人脂肪组织NYGGF4 mRNA表达的作用,但起效较慢,IL-6作用时间与脂肪组织NYGGF4 mRNA水平呈明显负相关关系。结论炎性细胞因子TNF-α、IL-6对人脂肪组织NYGGF4基因的表达呈现不同模式的调控作用,TNF-α可以促进人脂肪组织NYGGF4基因表达,而IL-6对NYGGF4的表达则具有抑制作用。