基底动脉尖综合征6例

基底动脉尖综合征(atrum Basilar ArterySyndrom RBAS)是指以基底动脉顶端为中心的5条血管交叉部,由于各种原因引起该区域的循环障碍。病因主要为栓塞和血栓形成,本病以老年人发病为多,平均年龄为65岁,以眩晕、吐和视物模糊为主诉,常有神经眼征。     

弥散张量成像对颅脑肿瘤与相邻脑白质纤维束解剖关系的评价

目的:评价弥散张量成像技术显示颅脑肿瘤与相邻脑白质纤维束解剖关系的价值。材料和方法:对5例正常志愿者及29例幕上星形细胞瘤及脑膜瘤进行弥散张量成像,在弥散各向异性图、彩色张量图及脑白质纤维束图上分析肿瘤与相邻脑白质纤维束的解剖关系,并对患者术前、术后的临床症状进行评价。结果:(1)9例脑膜瘤及11例Ⅰ-Ⅱ级星形细胞瘤推移相邻脑白质纤维束,患者术后临床症状明显改善。(2)6例Ⅲ-Ⅳ级星形细胞瘤及3例Ⅰ-Ⅱ级星形细胞瘤浸润、破坏相邻脑白质纤维束,患者术后的临床症状未明显改善。结论:弥散张量成像技术在显示颅脑肿瘤与相邻脑内主要白质纤维束的解剖关系方面具有重要价值,对神经外科术前治疗方案的确定具有重要指导作用。     

Ventilation imaging of the lung: Comparison of hyperpolarized helium-3 MR imaging with Xe-133 scintigraphy

RATIONALE AND OBJECTIVES: To compare hyperpolarized helium-3 (HHe) magnetic resonance imaging (MRI) of the lung with standard Xe-133 lung ventilation scintigraphy. MATERIALS AND METHODS: We performed a retrospective review of 15 subjects who underwent HHe MRI and Xe-133 lung ventilation imaging. Coronal MRI sections were acquired after a single inhalation of HHe gas, and standard posterior planar lung ventilation scintigraphy was performed during continuous breathing of Xe-133 gas. The first breath scintigram of each patient was compared with a composite MR image composed of the sum of the individual MR images and with the individual helium-3 MR images. Ventilation defects on the two imaging modalities were compared for size, conspicuity, and concordance in presence and location. Assessment was done separately for each of four lung quadrants. RESULTS: Comparing the composite HHe MR images with Xe-133 scintigraphy, ventilation defect size, conspicuity and concordance were the same in 67% (40/60), 63% (38/60), and 62% (37/60) quadrants, respectively. Comparing the individual HHe MR image sections with the Xe-133 ventilation scan, there was concordance between the ventilation defects in 27% (16/60) of quadrants. More defects were identified on the individual HHe MR images in 62% (37/60) of quadrants. CONCLUSION: There was good agreement between composite HHe MR image and first breath Xe-133 scintigraphic images, supporting the widely held assumption that HHe MRI likely depicts first breath lung ventilation.     

Efficient high-frequency body coil for high-field MRI.

The use of body coils is favored for homogeneous excitation, and such coils are often paired with surface coils or arrays for sensitive reception in many MRI applications. While the body coil's physical size and resultant electrical length make this circuit difficult to design for any field strength, recent efforts to build efficient body coils for applications at 3T and above have been especially challenging. To meet this challenge, we developed an efficient new transverse electromagnetic (TEM) body coil and demonstrated its use in human studies at field strengths up to 4 T. Head, body, and breast images were acquired within peak power constraints of <8 kW. Bench studies indicate that these body coils are feasible to 8 T. RF shimming was used to remove a high-field-related cardiac imaging artifact in these preliminary studies. P41RR13230     

12例Dandy—Walker综合征的临床CT与MRI分析

目的分析Dandy—Walker综合征的临床及cT与MR!影像特征。方法采用cT与MRI常规扫描，对12例Dandy—Walker综合征的临床表现、CT与MRI征象进行回顾性分析；结果12例Dandy—Walker综合征的CT与MRI表现归纳为①小脑蚓部缺失，小脑半球发育不良、完全分离，分离的小脑半球可以不对称；②第四脑室呈囊状、扇形、三角形显著扩张或后颅窝巨大囊状阴影与第四脑室相通；③窦汇异常抬高，越过人字缝／天幕抬高；④幕上脑室对称性扩张，脑积水。结论对Dandy—Walker综合征的诊断，CT扫描能够显示后颅凹及天幕上下脑的形态与结构，其CT表现具特征性；MRI可多平面扫描，无骨质伪影，显示后颅凹优于CT，在矢状面上可显示小脑、第四脑室、导水管、后颅凹囊肿以及与天幕的关系。CT与MRI扫描对Dandy—Walker综合征能够做出定性诊断，是术前诊断的主要依据，检查无痛苦，有重要的诊断和鉴别诊断价值。     

壶腹癌的MRI诊断

目的:探讨MRI诊断壶腹癌的价值。材料和方法:回顾性分析20例壶腹癌的MRCP及MRI影像资料,并与病理学诊断进行对照。结果:20例壶腹癌中显示局部软组织肿块13例、胆总管腔“截断征”17例、肝内胆管软滕样扩张19例、胆囊增大17例和“双管征”14例。结论:MRI,特别是MRCP能显示典型的“双管征”、“软藤征”和较清晰的癌肿范围,对壶腹癌有较高的诊断价值。     

The Usefulness of Magnetic Resonance Imaging in the Diagnosis of Anterolateral Impingement of the Ankle

The purpose of this study is to assess the sensitivity and specificity of magnetic resonance imaging (MRI) in the diagnosis of anterolateral impingement of the ankle and to assess the most helpful sequence in making the diagnosis. Twenty-four patients who had undergone ankle arthroscopy were chosen. Twelve patients had arthroscopically documented anterolateral impingement, and 12 patients with no impingement on arthroscopy served as controls. Two musculoskeletal radiologists and an orthopedic surgeon, blinded to the operative diagnosis, retrospectively reviewed selective MRI images in the sagittal, axial, and coronal planes. The sensitivities and specificities were calculated for all 3 reviewers. The Kendall coefficient of concordance was calculated for overall agreement among reviewers. Sensitivities varied from 0.75 to 0.83, whereas specificities varied from 0.75 to 1.00. Using the Fisher exact test of contingency, the sensitivities and specificities showed that all reviewers' interpretations were statistically significant with P = .039, .001, and .012, respectively. The axial images were felt to be most helpful in making the diagnosis. The physicians felt that the sagittal images were helpful in 67%, 83%, and 100%, respectively. MRI is a useful tool that can aid the clinician in the diagnosis of anterolateral impingement of the ankle. T1 sagittal images demonstrating displacement of the normal fat signal anterior to the fibula by scar can be useful and help to confirm the diagnosis.     

Intra-articular arteriovenous malformation of the knee

Two young men with longstanding suprapatellar masses are presented. The initial clinical diagnosis was of a synovial or soft tissue tumour. Magnetic resonance imaging showed the features of an arteriovenous malformation (AVM). Surgical exploration and biopsy confirmed the diagnosis. AVMs, although rare, should be considered as a possible diagnosis of a peri-articular swelling of the knee.     

齿状突骨折的MRI诊断

目的分析齿状突骨折的MRI表现,探讨MRI扫描在诊断齿状突骨折中的价值。方法回顾性分析我科CT确诊的52例齿状突骨折患者的MRI资料,MRI扫描包括横断面、矢状面、冠状面的T1WI及T2WI像。结果根据骨折部位将齿状突骨折分为三型,Ⅰ型:尖端骨折,本组3例;Ⅱ型:基底骨折,本组35例;Ⅲ型:枢椎椎体部骨折,本组14例。所有患者中,并发脊髓损伤16例,韧带损伤8例,3例合并颈椎脱位。结论MRI能清晰显示齿状突骨折线,确定骨折类型,显示椎旁软组织损伤,脊髓损伤。对于齿状突骨折患者,MRI对临床治疗有重要指导价值。     

Pitfalls in diagnosis of aortic dissection by angiography: Algorithmic approach utilizing CT and MRI

Dissection of the thoracic aorta is a life-threatening event requiring imaging studies to define the level of the tear and the intinmal flap. The “gold standard” has been angiography. This method may fail to demonstrate the dissection, however, due to overlap of the true and false lumens or a very thin flap that is imaged en face rather than tangentially. Computed tomography has a diagnostic accuracy of 95%, but can fail to image the dissection due to technical factors or a thrombosed false hunen. Magnetic resonance imaging requires a hemodynamically stable and cooperative patient. A diagnostic algorithm is proposed for diagnosis of aortic dissection based on renal function and the surgeon's imaging modality preference.