磁敏感成像与肾透明细胞癌病理分级的相关性研究

目的：评价磁敏感成像技术(SWI)划分透明细胞肾癌(CRCC)病理级别的可行性并比较SWI和坏死划分CRCC级别的能力。材料与方法回顾性分析35例病理证实的CRCC患者。所有患者均行常规MRI和SWI检查。肿瘤内磁敏感信号强度(ITSS)分为出血和微血管。评价高低级别CRCC ITSS和瘤内坏死的差异。比较ITSS和坏死鉴别高低级别CRCC的价值。结果35例患者中有31例在SWI上显示ITSS。4例瘤内未见ITSS的患者均为低级别CRCC。低级别CRCC的ITSS平均分数(1.24±0.72)明显低于高级别CRCC (2.70±0.48)(P<0.01)。10例低级别CRCC未见明显坏死。高低级别CRCC之间瘤内坏死的发生有明显差异(P<0.05)。ITSS区分高低级别CRCC的敏感性、特异性、阳性和阴性预测值分别为70.0%、100%、100%和89.3%;坏死为100%、40.0%、40.0%和100%。结论 SWI可评价瘤内ITSS并在术前区分CRCC的病理级别。     

Histological confirmation and biological significance of cartilage canals demonstrated using high field MRI in swine at predilection sites of osteochondrosis

Cartilage canal vessels in epiphyseal cartilage have a pivotal role in the pathogenesis of osteochondrosis/osteochondritis dissecans. The present study aimed to validate high field magnetic resonance imaging (MRI) methods to visualize these vessels in young pigs. Osteochondral samples from the distal femur and distal humerus (predilection sites of osteochondrosis) of piglets were imaged post‐mortem: (1) using susceptibility‐weighted imaging (SWI) in an MRI scanner, followed by histological evaluation; and (2) after barium perfusion using µCT, followed by clearing techniques. In addition, both stifle joints of a 25‐day‐old piglet were imaged in vivo using SWI and gadolinium enhanced T1‐weighted MRI, after which distal femoral samples were harvested and evaluated using µCT and histology. Histological sections were compared to corresponding MRI slices, and three‐dimensional visualizations of vessels identified using MRI were compared to those obtained using µCT and to the cleared specimens. Vessels contained in cartilage canals were identified using MRI, both ex vivo and in vivo; their locations matched those observed in the histological sections, µCT images, and cleared specimens of barium‐perfused tissues. The ability to visualize cartilage canal blood vessels by MRI, without using a contrast agent, will allow future longitudinal studies to evaluate their role in developmental orthopedic disease. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:2006–2012, 2013     

Layer-specific diffusion weighted imaging in human primary visual cortex in vitro

One of the most prominent characteristics of the human neocortex is its laminated structure. The first person to observe this was Francesco Gennari in the second half the 18th century: in the middle of the depth of primary visual cortex, myelinated fibres are so abundant that he could observe them with bare eyes as a white line. Because of its saliency, the stria of Gennari has a rich history in cyto- and myeloarchitectural research as well as in magnetic resonance (MR) microscopy. In the present paper we show for the first time the layered structure of the human neocortex with ex vivo diffusion weighted imaging (DWI). To achieve the necessary spatial and angular resolution, primary visual cortex samples were scanned on an 11.7 T small-animal MR system to characterize the diffusion properties of the cortical laminae and the stria of Gennari in particular. The results demonstrated that fractional anisotropy varied over cortical depth, showing reduced anisotropy in the stria of Gennari, the inner band of Baillarger and the deepest layer of the cortex. Orientation density functions showed multiple components in the stria of Gennari and deeper layers of the cortex. Potential applications of layer-specific diffusion imaging include characterization of clinical abnormalities, cortical mapping and (intra)cortical tractography. We conclude that future high-resolution in vivo cortical DWI investigations should take into account the layer-specificity of the diffusion properties.