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.     

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.     

头颈部良性神经源性肿瘤1H MRS的表现特点

目的：探讨头颈部良性神经源性肿瘤在单体素^1H MRS上的表现特点。材料和方法：共收集经单体素。HMRS检查，并经手术病理证实的头颈部神经源性肿瘤14例（神经鞘瘤11例，神经纤维瘤2例，颈动脉体瘤1例）。采用点分析波谱法（PRESS：TE=144ms，14例）和激励回波法（STEAM：TE=30ms，11例）进行。HMRS空间定位，以胆碱和脂质代谢物为标准评价所有肿瘤。波谱图上，胆碱和脂质分别在3．2ppm和0．9—1．4ppm区域识别。结果：采用PRESS后，14例神经源性肿瘤中检测出胆碱代谢物者11例，检出脂质代谢物者6例。胆碱和脂质代谢物同时检出者5例，仅检出胆碱者6例，仅检出脂质者1例，胆碱和脂质均未检出者2例。采用STEAM后，11例肿瘤中检出胆碱代谢物和脂质者分别为3例和8例。结论：头颈部良性神经源性肿瘤的单体素。HMRS表现具有多样性，多数肿瘤以长TEPRESS上胆碱峰的显示为特点，长TEPRESS能较STEAM更好地检出良性神经源性肿瘤内的胆碱代谢物。     

Proton magnetic resonance spectroscopy in childhood brainstem lesions

Background Diagnosis of brainstem lesions in children based on magnetic resonance imaging alone is a challenging problem. Magnetic resonance spectroscopy (MRS) is a noninvasive technique for spatial characterization of biochemical markers in tissues and gives information regarding cell membrane proliferation, neuronal damage, and energy metabolism. Methods We measured the concentrations of biochemical markers in five children with brainstem lesions and evaluated their potential diagnostic significance. Images and spectra were acquired on a 1.5-T imager. The concentrations of N-acetylaspartate, tetramethylamines (e.g., choline), creatine, phosphocreatine, lactate, and lipids were measured within lesions located at the brainstem using Point-resolved spectroscopy sequences. Results Diagnosis based on localized proton spectroscopy included brainstem glioma, brainstem encephalitis, demyelination, dysmyelination secondary to neurofibromatosis type 1 (NF 1), and possible infection or radiation necrosis. In all but one patient, diagnosis was confirmed by biopsy or by clinical follow-up. Conclusions This small sample of patients suggests that MRS is important in the differential diagnosis between proliferative and nonproliferative lesions in patients without neurofibromatosis. Unfortunately, in cases of NF 1, MRS can have a rather misdiagnosis role.     

乳腺良恶性病变的磁共振T2*W首过灌注成像与血管生成相关性研究

Objective： To study the diagnostic value of T2^＊-weighted first-pass perfusion imaging in breast tumors. Methods： We analyzed the magnetic resonance imaging （MRI） information along with the pathological and immunohistochemistry results. Magnetic resonance imaging was performed in 28 patients with breast tumor. The time to signal intensity curves were generated according to the T2^＊-weighted first-pass perfusion imaging. The curve＇s maximal signal intensity drop rate and maximal signal intensity decrease time were analyzed and compared with the pathological diagnoses after surgery. Results： Malignant breast lesions showed higher maximal signal intensity drop rate （44.69% ± 17.07 vs. 17.22% ±7.49, P 〈 0.001） than benign lesions, but there was no significant difference of maximal signal decrease time between those two lesions （23.94 s ± 4.92 vs. 20.02 s ± 6.83, P 〉 0.05）. Conclusion： The T2^＊-weighted first-pass perfusion imaging has enough sensitivity and specificity in breast tumor diagnosis.     

屈颈MRI对青年性上肢远端肌萎缩症的诊断价值

目的评价屈颈MRI对青年性上肢远端肌萎缩症的诊断价值。方法男性患者5例，平均年龄21岁，临床表现为一侧或两侧上肢远端肌萎缩。对照组为健康志愿者，21岁男性8例。2组均行常规及屈颈颈椎MR平扫，矢状、轴面SET1WI、T2WI、液体衰减反转恢复（FLAIR）序列扫描。结果常规颈椎扫描：5例患者下段颈髓变细；屈颈位MR扫描：下颈段颈6以下脊髓前屈、变扁平，矢状径4～6mm，硬膜囊后壁前移，硬膜后间隙明显增宽，可见多发条状、迂曲流空信号影及软组织信号。对照组：常规扫描，下颈段脊髓（颈6～胸2）可见颈膨大，屈颈位脊髓略变细（6～7mm），硬膜囊后壁无前移，硬膜后间隙未见扩张血管影。结论屈颈MRI有助于显示下颈段脊髓及硬膜囊改变，结合临床资料可准确诊断青年性上肢远端肌萎缩症。