Gadolinium-enhanced MR Imaging of Epiphyseal and Metaphyseal Marrow in Normal Piglets

Summary： The purpose of this study is to define the appearance of normal epiphyseal and metaphyseal marrow and normal changes of marrow due to fatty conversion on Gadolinium （Gd）-enhanced MR Imaging. Unenhanced and enhanced Tl-weighted MR imaging were performed in proximal and distal femoral ends of 8 healthy piglets at the ages of 2, 4, 6 and 8 weeks, respectively. The changes with age in signal intensity and enhancement ratio of the epiphyseal and metaphyseal marrow with age were examined. The correlation of MRI characteristics with histological findings was stud- ied. Our study showed that marrow of the metaphysis and of periphery of the 2nd ossification center were well vascularized hematopoietic marrow and had great enhancements. The enhancement ratio of metaphysis was greater than that of epiphyseal marrow and both enhancement ratios degraded gradually with age. The central regions of the epiphyseal ossification center and of the diaphysis were of fatty marrow and had little enhancement. It is concluded that on Gd-enhanced MR imaging the hematopoietic marrow of metaphysis and of periphery of the 2nd ossification center had greater enhancement than that of fatty marrow of central region of the 2nd ossification center. All of their enhancements decreased gradually with age.     

Comparative study of 3D-SPGR vs 2D-SE T1WI after enhancement in the brain

Summary:The utility of three-dimensional spoiled gradient recalled acquisition in steady state(3D-SPGR)imaging in the cerebral diseases was evaluated and 3D-SPGR after enhancement in depictingcontrast enhancement of all lesions and 2D-SE T1WI comparatively analyzed.117 patients were sub-jected to MRI by a GE.1.5T MR system.After performance of axial T1WI and T2WI in all pa-tients,MRA(3D-MOTSA)images were acquired in 6 cases(8 lesions)of aneurysms.After en-hancement,3D-SPGR images were obtained in all the remaining patients.Quality parameters(SNR,C and CNR)were calculated on enhanced 2D-SE T1WI and 3D-SPGR images.And a four-pointscale was used to measure the signal intensity of the main lesions on both sequences,then statisticalanalysis of the average score was performed with“t” test.Except for aneurysms,2D-SE T1WI de-tected 134 lesions and 3D-SPGR disclosed 147 lesions.It was found that there was no statistically sig-nificant difference between the two average scores as determined by the“t”test(t=1.     

Superparamagnetic Iron Oxide Labeling of Neural Stem Cells and 4.7T MRI Tracking in vivo and in vitro

Neural stem cells were labeled with superparamagnetic iron oxide (SPIO) and tracked by MRI in vitro and in vivo after implantation. Rat neural stem cells were labeled with SPIO combined with PLL by the means of receptor-mediated endocytosis. Prussian blue staining and electron mi-croscopy were conducted to identify the iron particles in these neural stem cells. SPIO-labeled cells were tracked by 4.7T MRI in vivo and in vitro after implantation. The subjects were divided into 5 groups, including 5×105 labeled cells cultured for one day after labeling, 5×105 same phase unla-beled cells, cell culture medium with 25 μg Fe/mL SPIO, cell culture medium without SPIO and dis-tilled water. MRI scanning sequences included T1WI, T2WI and T2WI. R2 and R2 of labeled cells were calculated. The results showed: (1) Neural stem cells could be labeled with SPIO and labeling efficiency was 100%. Prussian blue staining showed numerous blue-stained iron particles in the cyto-plasm; (2) The average percentage change of signal intensity of labeled cells on T1WI in 4.7T MRI was 24.06%, T2WI 50.66% and T2WI 53.70% respectively; (3) T2 of labeled cells and unlabeled cells in 4.7T MRI was 516 ms and 77 ms respectively, R2 was 1.94 s-1 and 12.98 s-1 respectively, and T2 was 109 ms and 22.9 ms, R2 was 9.17 s-1 and 43.67 s-1 respectively; (4) Remarkable low signal area on T2WI and T2WI could exist for nearly 7 weeks and then disappeared gradually in the left brain transplanted with labeled cells, however no signal change in the right brain implanted with unlabeled cells. It was concluded that neural stem cells could be labeled effectively with SPIO. R2 and R2 of labeled cells were increased obviously. MRI can be used to track labeled cells in vitro and in vivo.     

扩散张量成像在颅内占位性病变中的应用研究

目的:评价MRI扩散张量成像在颅内占位性病变中的应用价值。材料与方法:经手术及病理证实的星形细胞瘤、脑膜瘤、垂体瘤、转移瘤及脑脓肿共46例。行常规MRI扫描、扩散张量成像(DTI)检查。构建各向异性分数(FA)图,并测量病变及周围白质的FA值。结果:正常白质纤维在FA图上表现为高信号。肿瘤多呈低信号。在肿瘤存在时,周围白质纤维可表现为受推压移位或浸润破坏,破坏后FA值降低,表现为低信号。脓肿多呈低信号,其内部若有尚未破坏的白质纤维存在,可呈高信号。这些表现在常规MRI图像上均未清楚显示。结论:DTI可清楚显示占位性病变与周围白质纤维的解剖关系,指导临床制定手术方案。     

新生儿颅内出血的CT诊断

新生儿颅内出血较为常见,包括室管膜下,脑室内、脑实质内、蛛网膜下腔及硬脑膜下出血,     

动脉栓塞治疗甲状腺机能亢进症

甲状腺机能亢进症(Hyperthyroidism)简称甲亢,是常见的内分泌疾病,多见于女性,据估计女性人群中患病率高达1.9％。目前对本病的基本治疗方法仍然是抗甲状腺药物治疗(ATD)、~(131)I放射治疗和手术治疗三种方式。近年来国内外少数学者开展了介入栓塞治疗甲亢的临床研究,取得满意疗效。为提高对本病治疗方法的认识,现将甲亢的介入栓塞治疗综述如下:     

钆特醇及钆喷替酸葡甲胺在1.5、3.0 TMR下鼠脑胶质瘤模型增强扫描中的应用比较研究

目的 对比钆特醇及Gd-DTPA在1.5及3.0 T MR下的增强效果,比较两者在增强扫描中的应用价值.方法 42只CDF Fisher 344雄性大鼠,采用经皮导管脑内接种胶质瘤细胞,培育1周,制作鼠脑胶质瘤模型.将大鼠采用数字表法随机分为4组,分别为12、10、10、10只,进行1.5及3.0 T MR下注射钆特醇及Gd-DTPA增强效果对比、注射钆特醇在1.5及3.0 T两种场强下增强效果对比、1.5 T MR下使用标准剂量钆特醇与3.0 T下使用半剂量增强效果对比.两次扫描间隔24 h.选取注射对比剂前及注射后第1、3、5、7、9分钟时间点的T1加权图像,利用影像工作站分析计算各图像的信噪比(signal to noise ratio,SNR),对比噪声比(contrast to noise ratio,CNR)及对比增强比(contrast enhancement,CE),所得数据选用Student配对双尾t检验行统计学分析.结果 1.5 T MR下,注射Gd-DTPA后各时间点图像SNR、CNR和CE平均值分别为54.4±3.2、17.0±3.3、20.8±3.4;注射钆特醇后各值分别为53.2±3.2、17.2±3.1、20.8±3.2,两者差异无统计学意义(t值分别为2.247、0.403、0.076,P值均＞0.05).3.0 T MR下,注射Gd-DTPA后各时间点图像SNR、CNR和CE平均值分别为94.8±7.1、38.0±6.0、45.0±6.3;注射钆特醇后各值分别为95.5±2.9、37.2±2.7、45.6±2.8,两者差异亦无统计学意义(t值分别为0.303、0.573、0.357,P值均＞0.05).注射钆特醇在1.5 T MR下增强扫描后各时间点图像SNR、CNR和CE平均值分别为51.9±3.0、15.6±3.0、18.6±3.0;在3.0 T MR下图像各值分别为86.1±4.9、27.4±5.0、37.3±5.3,均高于1.5 T MRI图像,差异有统计学意义(t值分别为36.227、11.977、17.106,P值均＜0.05).1.5 T MR下注射标准剂量钆特醇增强扫描后,各时间点图像SNR、CNR和CE平均值分别为53.8±1.6、17.7±1.7、20.3±1.6;3.0 T MR下注射半剂量钆特醇增强图像各值分别为72.2±2.4、15.4±2.4、21.1±2.4,两者SNR、CNR均值差异有统计学意义(t值分别为31.503、5.137,P值均＜0.05),而两者CE均值差异无统计学意义(t=2.033,P＞0.05).结论 利用鼠脑胶质瘤模型,在1.5及3.0 T MR下注射钆特醇和Gd-DTPA行增强扫描,两者增强效果无明显差异;3.0 T MR下注射钆特醇行增强扫描,效果明显优于在1.5 T条件下使用;3.0 T MR下使用半剂量钆特醇与在1.5 T下使用标准剂量增强效果相仿,同样能取得满意的增强效果.因此,使用钆特醇可在保证增强效果的同时,在一定程度上降低使用MRI对比剂的风险,增加安全性.     

脑膜瘤MR扩散张量成像研究

目的探讨平均扩散系数(ADC)和各向异性分数(FA)在脑膜瘤诊断中的价值.资料与方法 28例脑膜瘤在治疗前行常规MRI及扩散张量成像(DTI).在T1WI增强、T2WI及FA图上确定肿瘤、水肿、肿瘤邻近及对侧正常白质区.测量、分析这些区域的FA值和ADC值.结果脑膜瘤Ⅰ级:水肿区ADC值高于肿瘤实体区、肿瘤邻近正常白质区及肿瘤对侧正常白质区(P<0.05).肿瘤邻近及对侧白质区FA值高于肿瘤实体区、水肿区(P<0.05).肿瘤实体区与水肿区FA值无显著性差异(P>0.05).脑膜瘤Ⅱ Ⅲ级:水肿区ADC值高于肿瘤实体区、肿瘤邻近及对侧白质区(P<0.05),实体区和肿瘤邻近及对侧白质区ADC值亦有显著性差异(P<0.05).肿瘤邻近白质区FA值高于实体区和水肿区(P<0.05).脑膜瘤Ⅰ级肿瘤实体区、水肿区、邻近白质区ADC值与脑膜瘤Ⅱ、Ⅲ间具有显著性差异(P<0.05),肿瘤邻近白质区FA值亦有显著性差异(P<0.05).结论 ADC图有助于区分肿瘤实体区和水肿区.FA图可清晰显示正常白质纤维和肿瘤的解剖关系,利于术前手术方案制定.结合常规MRI,DTI有助于脑膜瘤良、恶性分级.     

1H-MRS和CT在非酒精性脂肪肝诊疗中的应用研究

目的:应用磁共振质子波谱成像(1H-MRS)技术和CT定量诊断非酒精性脂肪肝(NAFLD)及评价药物疗效.方法:依中华医学会NAFLD诊断标准入选NAFLD患者22例,并与20例健康组对照.两组均行肝脏1H MRS扫描和CT平扫,计算肝内脂质含量(IHCL)和CT肝/脾比值.NAFLD组患者服用肝脂消胶囊8周,检测治疗前后IHCL和CT肝/脾比值的变化.结果:NAFLD组IHCL较正常组明显升高,CT肝/脾比值较正常组明显下降.经治疗后IHCL明显下降,CT肝/脾比值明显升高.结论:肝脏1H-MRS扫描可对肝脏内脂质含量进行准确定量,优于CT平扫.     

新生儿缺氧缺血性脑病MRI表现及其与预后的关系

目的 探讨足月新生儿缺氧缺血性脑病（HIE）的早期MRI表现及其与临床分度及预后的关系。资料与方法 以9例无窒息史的正常新生儿作对照,观察46例HIE患儿初期的MRI表现及28例复查病例的MRI表现。结果 （1）MRI能显示HIE患儿的12种早期异常征象,其中T1WI皮层高信号、侧脑室周围深部白质高信号以及蛛网膜下腔出血（SAH）或硬膜下出血（SDH）3种征象在轻度组与中、重度HIE组差异无显著性（P〉0．05）;而另外6种征象（弥漫性脑水肿、T1WI双侧基底节高信号伴内囊后肢高信号消失、弥漫性脑实质出血、脑回征、灰白质分界不清及胼胝体水肿）,在中、重度与轻度HIE组差异有显著性（P〈0．05）,说明这些征象是脑损伤严重的表现。（2）双侧基底节区广泛高信号伴内囊后肢高信号消失,弥漫性脑水肿。大面积脑梗死,脑回征以及脑实质广泛出血5种早期征象提示预后不良。常常会留下神经系统后遗症。结论 MRI可以客观反映新生儿HIE早期脑损伤的严重情况,并可早期评估预后。