A comparison of conventional and fast spin-echo sequences for the measurement of lesion load in multiple sclerosis using a semi-automated contour technique

Changes on serial assessments of brain MRI lesion load are used for monitoring therapeutic efficacy in patients with multiple sclerosis (MS). We assessed the accuracy and reliability of conventional spin-echo (CSE) and fast spin-echo (FSE) sequences for measurement of lesion volume using a semiautomated contour technique. Cranial CSE and FSE examinations of 18 patients with secondary progressive MS were studied. The mean lesion load was slightly higher with the CSE sequence (p = 0.002). Intraobserver variability was significantly higher for FSE than for CSE, according to both the coefficient of variation between two measurements (mean 2.48 % and 1.35 % respectively, p < 0.05) and back-transformed 95 % limits of agreement (1.005–1.060 for FSE; 0.988–1.019 for CSE). Although FSE sequences are quicker and the total lesion volume measurements are similar to those obtained with CSE, the poorer reproducibility raises doubts about the use of FSE to replace CSE in clinical trials. Received: 26 March 1996 Accepted: 4 April 1996     

Value of contrast-enhanced MRI of breast after silicone implant

Summary Early recognition of recurrence and work-up of clinically indeterminate lesions may be impaired after reconstruction with silicone implants due to superimposition of the implant or to scarring. This study was undertaken to evaluate the use of contrast-enhanced MRI in patients with silicone implant after breast cancer. Contrast-enhanded MRI was offered to 169 patients. Comparative two- to three-view mammography was also performed in 169 patients, as well as comparative sonography in 144 patients. Conventional imaging and clinical examination detected only 8/13 recurrences, whereas 12/13 were detected by MRI. One recurrence had been visible as a strongly enhancing 2-mm dot in a previous examination (2 years before), but was not called. It was therefore counted as false negative. In addition, multicentricity was detected by MRI alone in two of three cases. MRI correctly diagnosed scar tissue in all cases with indeterminate findings. However, due to false-positive calls caused by enhancing granulomas specificity could not be improved. Contrast-enhanded MRI allowed decisive additional information in our study group and improved the sensitivity significantly (concerning all diagnoses). Contrast-enhanded MRI is recommended in patients with diagnostic problems or high risk of recurrence after silicone implants.      

放射性肝纤维化过程的定量研究

经＾６０Ｃｏγ线照射大鼠肝区，通过光镜、电镜和图像分析仪、宣研究了照后１年肝脏的病理改变。结果表明，３０Ｇｙ组在照射后１年内逐渐发生了放射性肝纤维化病变。在肝纤维化发生过程中，肝细胞内糖原颗凿含量进行性减少，间质中胶原纤维含量进行性增加，网状纤维于照射１－３个月呈进行性增加。     

脑膜病变MRI异常强化类型与病因的相关性分析

目的 探讨各种脑膜病变脑膜MRI强化类型与病因的关系。方法 回顾性分析78例资料完整，MRI增强扫描脑膜异常强化的非脑膜瘤。结果 78例中，脑膜癌病16例（硬脑膜-蛛网膜型2例，软脑膜-蛛网膜下腔型11例，混合型3例）；感染性脑膜炎18例（硬脑膜-蛛网膜型3例，软脑膜-蛛网膜下腔型13例，混合型2例）；脑梗死22例（软脑膜-蛛网膜下腔型18例，混合型4例）；开颅术后15例（硬脑膜-蛛网膜型10例，混合型5例）；硬膜下积液（血肿）7例，均为硬脑膜-蛛网膜型。结论 MRI双倍剂量Gd-DTPA增强扫描对脑膜病变敏感性高，脑膜强化类型与各种病因侵犯脑膜三层结构的方式和程度有关。     

Cervical intramedullary cavernous angioma with MRI-proven haemorrhages

Summary Two contrasting cases of cervical intramedullary cavernous angioma in young female patients are reported. One patient had a 3-year course of step-wise progressive tetraparesis; at each of the five events intramedullary bleeding from a cryptic vascular malformation at C6–7 level was diagnosed by MRI. The other patient presented with one episode which led to MRI diagnosis of a vascular malformation at the C2 level. Both patients eventually underwent complete surgical excision of the angioma with subsequent steady improvement of the neurological deficit.     

腹部大血管病变的3D DCE-MRA诊断

目的 阐述3D动态增强磁共振血管造影（three-dimensional　dynamic contrast-enhanced magnetic resonance angiog-raphy,3D DCE-MRA）的原理及其在腹部大血管病变诊断中的价值。方法搜集32例腹部大血管3D DCE-MRA检查的影像资料,对其影像表现进行回顾性分析。结果（1）团注试验:对比剂通过肾动脉水平腹主动脉内的高峰时间为17-23s;（2）正常表现3例,清晰显示腹主动脉及其分支;（3）腹主动脉瘤7例,均显示主动脉受累段不规则增宽及实际的动脉腔;（4）腹主动脉夹层18例,均显示内膜片、真假两腔以及分支动脉起源的位置,显示破口12处、再破口16处;（5）动脉粥样硬化3例,均显示腹主动脉迂曲,管径粗细不均;（6）髂总静脉血栓形成1例,左髂总静脉未显影。结论3DDCE-MRA是一种非损伤性血管成像技术,对腹部大血管病变的诊断有重要意义。     

Heterodetic bicyclic decapeptide cyclo (Glu1 -Leu2 -Pro3-Gly4-Ser5-Ile6-Pro7-Ala8) cyclo-(1γ-5β) Phe9-Gly10

Bycyclic peptides are useful model molecules that can mimic the constrained local folding of a great number of natural peptides and proteins, such as ionophoric peptides, enzyme active site, and ligand-receptor active site. The synthesis of the bicyclic title compound with the liquid phase method is described with experimental details. Of particular interest is the heterodetic closure of the second ring. The peptide showed a complexing activity with metal cations like Ba²⁺, Ca²⁺, and Mg²⁺ . The free bicyclic peptide conformation in solution has been studied by means of NMR spectroscopy and a plausible structure model worked out with model building on NMR constraints is proposed.     

Nonlinear sensory cortex response to simultaneous tactile stimuli in writer's cramp.

Writer's cramp is a task-specific dystonia that leads to involuntary hand postures during writing. Abnormalities of sensory processing may play a pathophysiological role in this disorder. Electrophysiology studies in a monkey model of focal dystonia have revealed de-differentiation of sensory maps and the existence of single cells in hand regions of area 3b with enlarged receptive fields that extend to the surfaces of more than one digit. These changes may lead to abnormal processing of simultaneous sensory inputs. To study abnormal processing of simultaneous sensory information in adult humans with writer's cramp, we used functional magnetic resonance imaging to compare the response in primary sensory cortex with simultaneous tactile stimulation of the index and middle finger, with the response to stimulation of each finger alone. We tested five patients with writer's cramp and seven unaffected (normal) subjects. In the normal subjects, a linear combination of the activation patterns for individual finger stimulation predicts the pattern of activity for combined stimulation with 12% error. In writer's cramp patients, the linear combination predicted the combined stimulation pattern with 30% error. Results indicate a nonlinear interaction between the sensory cortical response to individual finger stimulation in writer's cramp. This altered interaction may contribute to the motor abnormalities.     

New insights on COPD imaging via CT and MRI

Multidetector-row computed tomography (MDCT) can be used to quantify morphological features and investigate structure/function relationship in COPD. This approach allows a phenotypical definition of COPD patients, and might improve our understanding of disease pathogenesis and suggest new therapeutical options. In recent years, magnetic resonance imaging (MRI) has also become potentially suitable for the assessment of ventilation, perfusion and respiratory mechanics. This review focuses on the established clinical applications of CT, and novel CT and MRI techniques, which may prove valuable in evaluating the structural and functional damage in COPD.     

虚拟现实技术在枢椎椎弓根螺钉精确植入中的应用研究

目的探索以虚拟现实技术为基础的枢椎椎弓根螺钉置人方法。方法选取8具成人颅一颈椎标本，采用改良四柱式定位框架固定于枕颈，使颅-颈-肩形成统一刚体，保持空间位置恒定，CT薄层扫描获取枢椎三维定位信息，采用Aero—Tech立体定向手术规划系统三维建模，设计安全、可视化、个体化的虚拟置钉路径，反复虚拟演示验证钉道安全后，导向弓把持下置人导向钢针，复查CT评价置钉的准确性。结果16个枢椎椎弓根置钉过程中，方向出现偏差（横突孔突破）1个，失败率为6．25％。结论目标椎弓根的容积三维重建、置钉路径可视化设计和虚拟演示，使操作过程简单、直观而精确，不需要线形和角性参数的测量；加上导向抓持装置提供的稳定性，使该技术具有很好的临床应用前景。