蝶鞍旁海绵状血管瘤的MRI表现

目的探讨蝶鞍旁海绵状血管瘤（Parasellar cavernous hemangioma,PCH）的MRI表现,以提高影像诊断水平。方法回顾性分析经手术及病理证实的23例PCH患者的病例资料。所有患者均行MRI扫描,19例行MR扩散加权成像（DWI）,7例行单体素1HMRS检查。结果病灶MRI扫描后T1WI呈等或稍低信号,T2WI呈明显高信号,增强扫描呈均匀或不均匀显著强化;19例DWI呈等或稍低信号;7例1HMRS均表现为NAA峰、Cr峰和Cho峰消失,其中6例出现Lip峰。结论PcH的MRI表现具有一定特征性,有助于提高术前定位及定性诊断的准确率。     

In vivo 1H‐MRS hepatic lipid profiling in nonalcoholic fatty liver disease: An animal study at 9.4 T

The applicability of the in vivo proton magnetic resonance spectroscopy hepatic lipid profiling (MR‐HLP) technique in nonalcoholic fatty liver disease was investigated. Using magnetic resonance spectroscopy, the relative fractions of diunsaturated (f_di), monounsaturated (f_mono), and saturated (f_sat) fatty acids as well as total hepatic lipid content were estimated in the livers of 8 control and 23 CCl4‐treated rats at 9.4 T. The mean steatosis, necrosis, inflammation, and fibrosis scores of the treated group were all significantly higher than those of the control group (P < 0.01). There was a strong correlation between the histopathologic parameters and the MR‐HLP parameters (r = 0.775, P < 0.01) where both steatosis and fibrosis are positively correlated with f_mono and negatively correlated with f_di. Both necrosis and inflammation, however, were not correlated with any of the MR‐HLP parameters. Hepatic lipid composition appears to be changed in association with the severity of steatosis and fibrosis in nonalcoholic fatty liver disease, and these changes can be depicted in vivo by using the MR‐HLP method at 9.4 T. Thus, while it may not likely be that MR‐HLP helps differentiate between steatohepatitis in its early stages and simple steatosis, these findings altogether are in support of potential applicability of in vivo MR‐HLP at high field in nonalcoholic fatty liver disease. Magn Reson Med 70:620–629, 2013. © 2012 Wiley Periodicals, Inc.     

申捷对放疗前后脑照射野内N-乙酰天门冬氨酸、胆碱及肌酸含量的影响

目的：利用磁共振波谱技术检测应用申捷（单唾液酸四己糖神经节苷钠）及放疗前后脑组织内N-乙酰天门冬氨酸、胆碱及肌酸含量变化,探讨申捷在预防及治疗早期放射性脑损伤中的作用。方法：将鼻咽癌患者随机分为两组,对照组给予放疗﹢肾上腺皮质激素;治疗组：放疗﹢肾上腺皮质激素﹢申捷。申捷为每日100mg,加入到生理盐水或5％葡萄糖水中静脉滴注。两组均于放疗前及放疗后2个月行颅脑MRI、MRS检查,并测定NAA/Cr和Cho/Cr值。结果：放疗结束后双颞叶NAA/Cr在对照组中明显下降（ P＝0.022）,在治疗组中无明显下降（P＝0.949）。而Cho/Cr在对照组中明显升高（P＝0.031）,在治疗组中无明显升高（P     

基于VTK磁共振波谱多体素空间位置的配准

本文利用可视化开发工具包VTK,实现了磁共振波谱多体素和二维医学图像的三维重建,得到多体素、多体素中单个体素和图像在空间的相对位置。对MRS多体素(也称化学位移成像CSI)的空间位置配准可以使医生更精确定位大脑中的病变组织,实施更细致的诊断和治疗计划。     

Investigation of metabolite changes in the transition from pre-invasive to invasive cervical cancer measured using (1)H and (31)P magic angle spinning MRS of intact tissue

The aim of this study was to determine the metabolic changes in the transition from pre-invasive to invasive cervical cancer using high-resolution magic angle spinning (HR-MAS) MRS. Biopsy specimens were obtained from women with histologically normal cervix (n = 5), cervical intraepithelial neoplasia (CIN; mild, n = 5; moderate/severe, n = 40), and invasive cancer (n = 23). (1)H HR-MAS MRS data were acquired using a Bruker Avance 11.74 T spectrometer (Carr-Purcell-Meiboom-Gill sequence; TR = 4.8 s; TE = 135 ms; 512 scans; 41 min acquisition). (31)P HR-MAS spectra were obtained from the normal subjects and cancer patients only (as acetic acid applied before tissue sampling in patients with CIN impaired spectral quality) using a (1)H-decoupled pulse-acquire sequence (TR = 2.82 s; 2048 scans; 96 min acquisition). Peak assignments were based on values reported in the literature. Peak areas were measured using the AMARES algorithm. Estimated metabolite concentrations were compared between patient diagnostic categories and tissue histology using independent samples t tests. Comparisons based on patient category at diagnosis showed significantly higher estimated concentrations of choline (P = 0.0001) and phosphocholine (P = 0.002) in tissue from patients with cancer than from patients with high-grade dyskaryosis, but no differences between non-cancer groups. Division by histology of the sample also showed increases in choline (P = 0.002) and phosphocholine (P = 0.002) in cancer compared with high-grade CIN tissue. Phosphoethanolamine was increased in cancer compared with normal tissue (P = 0.0001). Estimated concentrations of alanine (P = 0.01) and creatine (P = 0.008) were significantly reduced in normal tissue from cancer patients compared with normal tissue from non-cancer patients. The estimated concentration of choline was significantly increased in CIN tissue from cancer patients compared with CIN tissue from non-cancer patients (P = 0.0001). Estimated concentrations of choline-containing metabolites increased from pre-invasive to invasive cervical cancer. Concurrent metabolite depletion occurs in normal tissue adjacent to cancer tissue.     

Recent advances in breast MRI and MRS

Breast MRI is an area of intense research and is fast becoming an important tool for the diagnosis of breast cancer. This review covers recent advances in breast MRI, MRS, and image post-processing and analysis. Several studies have explored a multi-parametric approach to breast imaging that combines analysis of traditional contrast enhancement patterns and lesion architecture with novel methods such as diffusion, perfusion, and spectroscopy to increase the specificity of breast MRI studies. Diffusion-weighted MRI shows some potential for increasing the specificity of breast lesion diagnosis and is even more promise for monitoring early response to therapy. MRS also has great potential for increasing specificity and for therapeutic monitoring. A limited number of studies have evaluated perfusion imaging based on first-pass contrast bolus tracking, and these clearly identify that vascular indices have great potential to increase specificity. The review also covers the relatively new acquisition technique of MR elastography for breast lesion characterization. A brief survey of image processing algorithms tailored for breast MR, including registration of serial dynamic images, segmentation and extraction of morphological features of breast lesions, and contrast uptake modeling, is also included. Recent advances in MRI, MRS, and automated image analysis have increased the utility of breast MR in diagnosis, screening, management, and therapy monitoring of breast cancer.     

Nuclear magnetic resonance and the brain

Summary The first successful demonstrations of nuclear magnetic resonance (NMR) in bulk matter were reported in 1946 (Bloch, Hansen and Packard 1946; Purcell, Torrey and Pound 1946). Since then NMR has become a widespread technique for investigating matter of all kinds. In the 1970's NMR was applied to living systems, including man, in 2 distinct approaches. One application was in the production of images (Lauterbur 1973), called Magnetic Resonance Imaging or MRI, and the other in the production of NMR spectra (Moon and Richards 1973; Hoult et al. 1974), called Magnetic Resonance Spectroscopy or MRS. By appropriate manipulation of the NMR signal an NMR image may be generated. This can be a 2D image of a single slice, or a set of 2D images of parallel slices, or a 3D image. 2D images may be obtained directly in any orientation, axial, coronal, sagittal. The method uses no ionizing radiation and is inherently safe. It is non-invasive, although paramagnetic solutions may be injected intravenously to improve contrast. MRI images observed in normal clinical practice are maps of the NMR signals from water and fat in the tissues; they depend on proton density, but also significantly on the relaxation times T₁ and T₂. Images can be provided of flow (MR angiography) and diffusion (free, restricted or anistropic). Images are typically 512×512 pixels with spatial resolution of about 0.5mm. The images can be correlated with anatomical structures and indeed MRI is a primary source of such structures with localization precision of 0.5mm as in CT. Normal imaging times are about 5mins, but fast images of lower resolution can be obtained in 50ms, enabling real time movie images to be generated. Recording sessions are typically 1hr. The NMR spectrum from living tissue gives a non-invasive measure of the concentration of each molecular species. Such spectra (MRS) provide information concerning the biochemistry of the body's metabolism and associated pathology.³¹P spectra report concentrations of ATP, ADP, phosphocreatine, inorganic phosphate, other metabolites and also local pH.¹H spectra (with suppression of water and lipid responses) give spectra from lactate, NAA, choline, creatine and other components. Spectroscopic Imaging (SI) combines MRI and MRS to provide spectra simultaneously from an array of pixels or voxels, each usually several cm³ in size in an overall time of order 20 mins. This procedure provides a spatial map of the whole spectrum or individual maps of each molecular species. Two recent developments have demonstrated that NMR can provide functional mapping of the normal human brain, and map the response of the human cerebral cortex to physiological stimulation.Support from NIH grant P41 RR02278 is gratefully acknowledged.