MRI及31P-MRS在脂质沉积性肌病中的诊断

目的:应用磁共振成像(MRI)及磷频谱(31P-MRS)评价脂质沉积性肌病(LSM)的影像表现,探讨其临床应用价值.方法:对经病理证实的6例LSM和17例健康对照者进行MRI及31P-MRS检查.结果:6例LSM患者大腿后组肌群和内侧肌群T1 WI及T2 WI上均表现为多发小斑点状高信号,T2 WI抑脂后信号减低;LSM组PCr(磷酸肌酸)、PCr/ATP(三磷酸腺苷)和磷酸化能力(PP)较对照组明显降低(P＜0.05),二磷酸腺苷(ADP)、Pi(无机磷)、Pi/ATP、Pi/PCr较对照组明显增高(P＜0.05),PH与对照组无明显差别(P=0.6395).结论:MRI联合31P-MRS检查有利于LSM的诊断、鉴别诊断.     

脂质沉积性肌病一例

病例资料 患者,男,58岁.1年前无明显诱因出现左小腿酸痛,并进行性加重.近1个月来,行走困难,出现间歇性跛行.查体:全身肌容量正常,四肢肌张力正常.左小腿肌肉压痛,左下肢近端肌力4级,远端5级;右下肢肌力5级,病理反射未引出.     

质子磁共振波谱对线粒体脑肌病的诊断作用

目的 探讨质子磁共振波谱在线粒体脑肌病中的特点及其诊断价值.方法 对2例临床诊断为线粒体脑肌病的患者行常规磁共振及质子磁共振波谱检查,分析其谱线特点.结果 2例患者行质子磁共振波谱检查均有明显的乳酸峰出现,1例在常规磁共振成像上显示正常的区域也有小的乳酸峰.结论 质子磁共振波谱可以早期反映线粒体脑肌病的异常代谢,有助于提高诊断的准确性.     

人肝脏活体31P MRS谱图后处理的应用研究

目的探讨肝脏31P MRS谱图后处理的最佳途径.方法用1.5T超导MR扫描仪,Heart/Liver频谱表面线圈,俯卧位加呼吸门控(Resp/Trigger)采集数据,对象是15～58岁正常志愿者或肝硬化、肝肿瘤等肝病患者,数据采集后利用各种后处理方法è分别处理,加以比较.结果正常志愿者肝脏31P MR谱图20例,31P MRS谱图的后处理可简单地归结为在J-coupling型峰类型下,进行Filter、Zero-filling、Curve fitting处理,所有被检查者均可获得肝脏良好的31P MRS谱图、各种物质浓度及其相互间的比率.结论波谱后处理方法简便易行,充分利用Edit的编辑技巧,能得到符合要求的曲线和精确的数据.     

^31P-MRS检测标记基因表达肝直接基因转导初步研究

目的：探讨^31P-MRS技术在兔VX2肝移植瘤模型经AdCMVIL12-IRES-CKb腺病毒基因转导后通过标记基因间接表达的可行性。方法：健康新西兰大白兔20只,采用开腹包埋法建立兔VX2肝肿瘤模型,将种植成功的18只实验兔随机分成两组,于3周左右行31P-MRS扫描后采用开腹法分别将等量AdCMVIL12-IRES-CKb腺病毒和生理盐水注射到两组瘤兔肿瘤及周围组织中,肌酸水溶液饲养5天后再次行31P-MRS扫描。同时通过免疫组化、琼脂糖凝胶蛋白印迹法（Western Blot）对IL-12和CK进行检测。结果：经AdCMVIL12-IRES-CKb腺病毒治疗后的兔肝VX2肿瘤组织PCr峰较对照组明显升高,分别为（0.84±0.41）、（0.23±0.29）mmol/L,两组治疗前后PCr比较,P值小于0.05,差异有统计学意义;免疫组化在治疗组肝脏局部组织中检测到IL-12的表达,对照组未见表达;Western Blot法检测到治疗组CKB的表达,但对照组未见表达。结论：通过31P-MRS成像检测病毒直接基因转导后体内肝脏的基因表达是可行的。     

线粒体脑肌病影像研究进展

线粒体脑肌病（mitochondrial encephalomyopathy,ME）指由于线粒体基因或细胞核基因缺失或发生点突变导致的线粒体结构和功能异常,引起机体能量代谢障碍,主要累及脑和横纹肌的一类少见疾病[1],1962年Luft等在1例年轻的瑞典女性患者肌肉活检中,发现了异常线粒体,首次报道了线     

线粒体脑肌病卒中样病灶的磁共振诊断及波谱分析

目的 探讨线粒体脑肌病伴高乳酸血症与卒中样发作事件(MELAS)脑内卒中样病灶的磁共振成像表现及~1H磁共振波谱特征.方法 回顾分析7例MELAS患者的临床及磁共振检查资料.结果 本组病例所行12次磁共振检查共计评价超急性期卒中样病变12个、急性期病灶12个、亚急性10个和慢性病灶6个.MELAS脑内卒中样病灶最初表现为局限大脑皮层的水肿信号灶,可累及皮层下区,多发于颞、枕、顶叶.磁共振扩散加权成像,病变在超急性期(3 d内)表现为以细胞毒性水肿为主,呈边界清楚的高信号灶;急性期(4～7 d)、亚急性期(2～4周)至慢性期(＞4周)病变逐步扩大,边界变模糊,以血管源性水肿为主.~1H磁共振波谱分析,脑卒中样病变在早期以高耸的双乳酸峰为特点,伴N-乙酰天门冬氨酸(NAA)等脑代谢物成分不同程度降低;随后,乳酸峰逐步降低,NAA等代谢物浓度可部分恢复.结论 MELAS卒中样病灶主要累及大脑皮层和皮层下区,细胞毒性水肿出现早但持续时间短,~1H磁共振波谱以典型的双乳酸峰为特征并伴有NAA浓度降低.     

31P MR波谱分析在肝细胞癌、肝硬化及正常肝组织中的临床应用价值

目的利用肝脏31P MRS分析活体无创性鉴别肝细胞癌、肝硬化及正常肝组织.方法对随机选择的正常人、肝硬化和肝癌患者共33例66个有效体素分3组进行方差分析.结果 3组研究对象每组13个变量中的10个具有显著性统计学意义(P＜0.05),3组研究对象的该10种变量两两之间存在明显差异,且与谱图分析结果一致.结论肝脏31P MRS分析可以作为活体无创性鉴别肝细胞癌、肝硬化及正常肝组织的有效方法.     

成人线粒体脑肌病的MRI和1H-MRS诊断价值

目的 分析MRI和1H-MRS对线粒体脑肌病的诊断价值.方法 经病理活检确诊的 6例成人 (男3例,女3例)线粒体脑肌病患者采用1.5T磁共振仪扫描,其中3例行1H-MRS检查,并分析MRI和1H-MRS的表现. 结果6例线粒体脑肌病患者MRI显示病变累及多个脑叶,多位于皮层及皮层下白质,并可同时累及大脑深部灰质和大脑皮层.脑梗死样病灶呈斑片状或楔形,非对称性.T1WI为低信号或等低信号,T2WI为高信号.急性期病变区域脑组织轻度肿胀,慢性期全脑萎缩,并可见皮质层状坏死.4例行MR增强扫描未见强化.3例1H-MRS检查均显示病灶内Lac峰明显升高和NAA峰不同程度的降低.结论 线粒体脑肌病MRI表现具有一定的特征,1H-MRS可提供更多脑组织代谢信息,对本病诊断具有重要的价值.     

基于自组织特征映射神经网络的肝脏^31P磁共振波谱分析

目的：探讨基于神经网络的^31PMR波谱在辨别肝细胞癌,正常肝和肝硬化中的价值。方法：运用自组织特征映射神经网络（SOM）分析66个^31P MRS数据,其中包括肝细胞癌（13个样本）,正常肝脏（16个样本）和肝硬化（37个样本）。结果：^31P MRS可以用于肝细胞癌与肝硬化结节的诊断和鉴别诊断,经四个实验证明,基于神经网络模型的。^31P MR波谱数据分析可以将肝细胞癌的诊断正确率从85．4％提高到92．31％。结论：基于神经网络模型的。^31PMRS波谱数据分析为活体肝细胞癌的诊断提供了一种有价值的诊断手段。     

应用表观扩散系数进行星形细胞肿瘤分级：单参数法与双参数法优越性的比较

目的评估MRI中应用最小表观扩散系数（ADCs）,NADC差值进行星形细胞肿瘤分级的实用性。方法医院的伦理审查委员会通过了该项回顾性研究并免除了知情同意书。本研究评估了50例（23例男性,27例女性;平均年龄53岁）新确诊的星形细胞肿瘤病人。2名不了解临床信息的观察者．独立对肿瘤伴或不伴对比增强的实质部分手工设置3～5个感兴趣区（40～60mm^2）,进行测量并计算其平均ADCs。选定ADCs的最大及最小值,并计算其间差值即ADC差值。     

1.5-T MR of the knee: the correlations with arthroscopy

The authors report their experience of knee articular pathologies studied with MR imaging. Forty patients (36 with and 4 without articular trauma) were examined with both MR imaging and arthroscopy. Arthroscopic findings were correlated with MR results in order to evaluate the accuracy of the latter in detecting meniscal tears. MR images were obtained with a 1.5 T unit and a transmit-receiver surface coil. Spin-echo sequences and, occasionally, fast-scan sequences were used both in the coronal and in the sagittal planes. High resolution MR imaging clearly depicted knee anatomy. As far as meniscal lesions were concerned, the authors employed a grading system to classify intrameniscal signals, as proposed by Lotysch. The preliminary results are encouraging and suggest the use of MR imaging as the first imaging modality for use in knee pathology before arthroscopy is performed.     

Acute cervical spine trauma: evaluation with 1.5-T MR imaging

Twenty-one patients with acute neurologic deficits following cervical spine trauma were evaluated with magnetic resonance (MR) imaging (n = 21), computed tomography enhanced with intrathecal contrast material (CT myelography) (n = 18), myelography (n = 13), cervical spine radiography (n = 21), and intraoperative sonography (n = 7). MR imaging proved superior to other modalities in demonstrating parenchymal spinal cord injuries and cervical intervertebral disk herniation. Although both T1- and T2-weighted studies appear necessary to evaluate the anatomic relationship of the spinal cord, thecal space, intervertebral disks, and surrounding osseous and ligamentous structures, T2-weighted sequences were more sensitive than T1-weighted studies for detection of spinal cord injury. CT myelography was superior to MR imaging in demonstrating cervical spine fractures. In most cases, myelography revealed no information that was not apparent from both CT and MR imaging studies. Preliminary experience with MR imaging of acute cervical spine trauma suggests that it should be the study of choice in symptomatic patients who are otherwise clinically stable. CT may still be required in selected patients to evaluate complex fractures.     

Evaluation of the acetabular labrum at 3.0-T MR imaging compared with 1.5-T MR arthrography: preliminary experience

Institutional review board approval and informed consent were obtained for this HIPAA-compliant study. The purpose of this study was to prospectively compare imaging of the acetabular labrum with 3.0-T magnetic resonance (MR) imaging and 1.5-T MR arthrography. Eight patients (four male, four female; mean age, 38 years) with hip pain suspicious for labral disease were examined at both MR arthrography and MR imaging. Presence of labral lesions, paralabral cysts, articular cartilage lesions, subchondral cysts, osteophytes, and synovial herniation pits was recorded. There was arthroscopic correlation of findings in five patients. MR imaging depicted four surgically confirmed labral tears that were identified at MR arthrography, as well as one that was not visualized at MR arthrography. MR imaging helped identify all other pathologic conditions that were diagnosed at MR arthrography and helped identify one additional surgically confirmed focal articular cartilage lesion. These results provide encouraging support for evaluation with 3.0-T MR imaging over 1.5-T MR arthrography.     

Diffusion-tensor fiber tractography: intraindividual comparison of 3.0-T and 1.5-T MR imaging

PURPOSE: To prospectively evaluate the depiction of brain fiber tracts at 3.0- versus 1.5-T diffusion-tensor (DT) fiber tractography performed with parallel imaging. MATERIALS AND METHODS: Institutional review board approval was obtained, and each subject provided written informed consent. Subjects were 30 healthy volunteers (15 men, 15 women; mean age, 28 years; age range, 21-46 years). Single-shot spin-echo echo-planar magnetic resonance (MR) sequences with parallel imaging were applied. Four fiber tracts were reconstructed: corticospinal tract (CST), superior longitudinal fasciculus (SLF), corpus callosum (CC), and fornix. Two neuroradiologists compared 3.0- and 1.5-T tractography in terms of fiber tract depiction by using five depiction scores (scores 0-4) and numbers of reconstructed tract fibers and in terms of lateral asymmetry in the CST by using numbers of reconstructed fibers. The Wilcoxon signed rank test was applied for statistical analysis. RESULTS: Visual scores for both CST hemispheres (P < .001), the right SLF (P = .005), the CC (P = .01), and the right fornix (P = .04) were higher at 3.0-T DT tractography. Larger numbers of CST (right, P = .008; left, P < .001), SLF (right, P = .001; left, P = .02), and fornix (bilaterally, P = .02) tract fibers were depicted at 3.0 T. The asymmetry index for the CST was lower (P < .001) at 3.0 T. Visual scores for the left SLF and the left fornix and numbers of CC tract fibers were not significantly different. CONCLUSION: Depiction of most fiber tracts was improved at 3.0-T DT tractography compared with depiction at 1.5-T tractography.     

Time-of-flight MR angiography: comparison of 3.0-T imaging and 1.5-T imaging--initial experience

Intracranial three-dimensional time-of-flight (TOF) magnetic resonance (MR) angiography was performed in seven healthy volunteers and eight patients with both 1.5-T and 3.0-T MR systems with standard and high spatial resolutions (true voxel sizes, 0.48 x 0.75 x 2.00 mm and 0.30 x 0.44 x 1.00 mm, respectively). Superior image quality and significantly better depiction of small vessel segments and vascular disease were observed at high-spatial-resolution 3.0-T TOF MR angiography but not at standard 1.5-T or standard 3.0-T TOF MR angiography (P <.01, respectively). Intracranial high-spatial-resolution TOF MR angiography at 3.0-T imaging provides diagnostic improvement in studies of cerebrovascular disease.     

MR imaging of the brachial plexus: comparison between 1.5-T and 3-T MR imaging: preliminary experience

Objective  

To compare 1.5-T and 3-T magnetic resonance (MR) imaging of the brachial plexus.     

Conventional 3-T MRI and 1.5-T MR Arthrography of Femoroacetabular Impingement

OBJECTIVE: This article provides a review of femoroacetabular impingement (FAI) and the role MRI is attempting to fulfill in this complex and sometimes controversial condition. A perspective on the current status and on the advantages of 1.5-T MR arthrography is presented, and its usefulness in this setting is compared with the potential of nonarthrographic 3-T MRI. CONCLUSION: With its increasing availability, 3-T MRI has the potential to provide routine, less invasive assessment of the hip for FAI.     

Bone marrow patterns in aplastic anemia: observations with 1.5-T MR imaging

Six patients diagnosed as having aplastic anemia underwent magnetic resonance (MR) imaging. The bone marrow in the lumbar spine, pelvis, and proximal femora was examined in each case. One patient had a normal marrow signal intensity (SI) and pattern and was considered cured of disease. The other patients had varying numbers of focal low-SI areas interspersed with high-SI areas in the marrow of the spine. The pelves and proximal femora of all patients had diffuse high-SI marrow without focal abnormalities. Biopsy of a lumbar vertebral body in one patient demonstrated that the focal low-SI areas may have been islands of active hematopoietic cells scattered in otherwise fatty marrow. MR may prove to be a valuable, noninvasive method of following the response of patients with aplastic anemia to therapy; more investigation is necessary before this can be definitely concluded.     

Biopsy needles and devices: Assessment of ferromagnetism and artifacts during exposure to a 1.5-T MR system

Forty-eight biopsy devices (needles, stylets, guide wires, biopsy guns, etc) were evaluated for ferro-magnetism (n=48) and artifacts (n=43) in a 1.5-T magnetic resonance (MR) system, with previously described techniques. Forty-five of the 48 devices were found to be ferromagnetic. Artifacts varied, depending on the type and size of the component material(s) of the device. Most of the commercially available biopsy devices are not useful for MR imaging-guided biopsy procedures because of the presence of ferromagnetism and associated artifacts.