Use of superparamagnetic contrast media to suppress signal from flowing spins: Preliminary experience

The authors describe their preliminary experience with the use of superparamagnetic magnetic resonance (MR) imaging contrast media for suppression of signal from flowing blood. The goal of this work was to determine if a superparamagnetic contrast agent could successfully eliminate blood signal during cardiac-gated MR imaging, thereby eliminating or reducing flow artifacts associated with the complex and variable hemodynamics within the heart chambers. Imaging and data analysis were performed in 17 dogs subjected to experimental myocardial infarction as part of a parallel project. Six doses (0.2, 1, 2, 3.5, 4, 5, and 10 mg/kg) of AMI-25, an experimental contrast agent, were used in the study. Spin-echo imaging was performed immediately before and every 5 minutes (for an average of 25 minutes) after bolus injection of the contrast agent. Variations in the image signal-to-noise ratio relative to a baseline (before injection of contrast agent) image were assessed as a function of dose and time. Preliminary results suggest that a considerable reduction in blood flow artifacts and, hence, increases in image signal-tonoise ratio can be achieved at doses greater than or equal to 3.5 mg/kg, for approximately 20 minutes after injection. Doses equal to or less than 2 mg/kg and images obtained more than 20 minutes after injection (regardless of dose) did not reliably show hemodynamic artifact suppression.     

Effect of different questionnaire formats on reporting of occupational exposures

During an exposure monitoring study, 78 saw maintenance tradesmen were randomly assigned to be interviewed about their exposures using one of two questionnaire formats: open-ended and partly prompted questions about five categories of materials; and detailed prompting about 75 agents. The more open-ended questionnaire elicited fewer exposure responses overall, but more responses about agents not included on the detailed questionnaire. Composite materials and trade name products were more frequently cited as exposures than individual metals or compounds. Validity of responses was ascertained using air measurements (individual metals) or observations of the employees (composite materials). Sums of sensitivities and specificities were very low (near 1.0) for most of the metals for both types of questionnaire. For composite materials, validity improved substantially. Sensitivities with the partly prompted format (0.44–0.85) were always lower than with detailed prompting (0.80–1.00). Specificities were usually, but not always, higher with partial prompting (0.66–0.92) than with detailed prompting (0.18–0.86). Selection of questionnaire format for an epidemiologic study would depend on the likely prevalence of exposure in controls and the effects of trade-offs in sensitivity and specificity.     

肝癌及癌旁组织中P~(53)基因第七外显子转录水平的表达差异及临床意义

目的 :研究启东区肝癌中 P53基因第七外显子转录水平的表达及其与患者临床病理特征间的关系。方法 :通过 RT- PCR确定 P53基因第七外显子在 47对肝癌标本中的表达 ,并分析其与肝癌患者临床病理特征间的关系。结果 :P53基因第七外显子在肝癌及其癌旁组织中均显示差异表达 ,其中 1 7例为上调表达 ,30例为下调表达 ,上下调表达之间差异显著 ;女性、年龄≥ 45岁、AFP( + )、HBs Ag( + )、癌栓 ( + )、肝硬化、病理 Edmondson's 级的病例中 P53基因第七外显子均呈显著下调表达 ;Edmondson's I级病例肝癌组织中 P53基因的 EI显著高于 Edmondson's 级病例。结论 :启东肝癌中 P53基因第七外显子转录水平上存在表达差异 ,且其异常表达与肝癌的临床病理特征有关     

两种靶控方法输注异丙酚和瑞芬太尼的安全性和有效性比较

目的 比较靶控血浆浓度和效应室浓度输注异丙酚和瑞芬太尼的安全性及有效性。方法 选择44例腹腔镜胆囊切除的病人,年龄18～65岁,ASA Ⅰ～Ⅱ级,随机分为靶控血浆浓度组(P组)和效应室浓度组(E组)。设定异丙酚和瑞芬太尼的靶浓度分别为4 μg/ml和2 ng/ml。观察给药后意识消失时间、血液动力学变化以及听觉诱发电位指数(AAIs)的变化。术中调整两药靶浓度保持AAIS低于20。记录术毕停药后自主呼吸恢复和睁眼时间和AAIs的恢复。结果 E组意识消失的时间[(0.45±0.10)min]明显短于P组;此时两药的用量也明显高于P组。两组均能引起明显的低血压,但降低程度相似,且均未见严重的心血管副作用。AAIs在意识消失时P组为41±22;E组49±16:但插管时均在20以下。术中血液动力学保持较低水平(P<0.01)。两组的插管评分、麻醉质量评分相似。术后自主呼吸恢复时间和睁眼时间两组均无统计学差异。Aldrate评分及手术结束时疼痛评分差异均无显著性。结论靶控血浆和效应室浓度输注均可达到满意的麻醉效果,但靶控效应室诱导时间更短,且无明显心血管副作用。     

心脏瓣膜置换术后中远期疗效分析

目的　分析探讨心脏瓣膜置换术的中远期疗效。方法　 1978年至 2 0 0 1年 12月 ,行瓣膜置换手术 2 14 1例 ,同期随访 16 81例 ,计 80 2 1 1人·年 ,平均 4 77人·年。通过回顾病因、手术方式、瓣膜类型等因素 ,观察术后病人心功能改善情况 ,病死率及并发症等 ,采用t检验 ,多因素回归等统计学方法分析。结果　 92例死亡。总体生存率 5年为 (92 3± 2 2 ) % ,10年生存率为 (90 1± 2 7) %。并发症有血栓栓塞、机械瓣膜功能障碍、瓣周漏、溶血、机械瓣膜感染性心内膜炎。术后心功能 (NYHA)与术前比较有明显的提高。结论　 1.机械瓣置换术后中远期疗效满意 ,病死率及并发症均较低 ;与术前心功能和手术种类直接相关 ;2 .使用保留瓣下结构及三尖瓣成形术对术后心功能恢复有明显效果 ;3.术中良好心肌保护是提高手术成功率的关键。     

脊柱原发性肿瘤的手术治疗策略

目的 回顾性研究对脊柱原发性肿瘤患者应用多种入路实施手术治疗的效果及并发症。探讨脊柱原发性肿瘤的手术治疗策略。方法 自1998年7月至2005年7月，共收治脊柱原发性肿瘤患者135例。其中，骨髓瘤25例，神经纤维瘤、神经鞘瘤23例，巨细胞瘤17例，血管瘤15例，淋巴瘤9例，软骨肉瘤7例，骨母细胞瘤6例，嗜酸性肉芽肿6例，尤文肉瘤5例，动脉瘤样骨囊肿4例，粒细胞肉瘤4例，骨肉瘤3例，恶性纤维组织细胞瘤3例i血管内皮瘤2例，骨纤维异样增殖症2例，骨软骨瘤2例，脊索瘤2例。病变累及颈椎13例，胸椎79例，腰椎43例。出现神经系统受累者92例，其中Frankel分级A、B级9例，C、D级83例；无神经系统受累者43例。前后路联合手术切除肿瘤18例，经后路侧前方手术13例，经前路切除肿瘤73例，经后路切除肿瘤31例。结果 135例患者中，126例（93.3％）术后疼痛得到不同程度的缓解，9例术后疼痛无明显减轻。92例术前有神经系统受累的患者中，86例术后麻痹症状得到不同程度的缓解。在随访期内未见严重并发症。11例患者术后出现脑脊液漏，经应用抗生素及抬高床尾治疗后愈合。3例应急性溃疡患者，经输血及抗酸药治疗溃疡愈合。皮下气肿3例，伤口浅表感染3例，神经根损伤2例，内固定物松脱2例，瘫痪加重1例。结论 对于脊柱巨细胞瘤或软骨肉瘤等恶性肿瘤破坏单个或相邻的两个脊椎时，应采用前后路联合手术切除肿瘤。术前根据肿瘤的Tomita或WBB分期设计手术方案，合理切除肿瘤，降低术后复发率。     

Gd-DTPA-enhanced MR in thoracic disc herniations

Summary The Gd-DTPA-enhanced magnetic resonance findings in two patients with herniated thoracic intervertebral discs are reported. The first patient was a 56-year-old woman with a small subligamentous T6-7 disc herniation, slightly lateralized to the right. The second patient was a 51-year-old man with a central and right posterolateral disc herniation, including a large calcified fragment, at the T8-9 level. The nonenhanced MR examination revealed the presence of an extradural mass lesion in both patients, impinging upon the dural sac and compressing and displacing the spinal cord posteriorly. The lesion was slightly hypointense on both T1- and T2-weighted spin echo sequences. Following intravenous injection of Gd-DTPA in a dosage of 0.1 mmol/kg body weight, enhancement of the posterior longitudinal ligament was noted and triangular areas of contrast uptake were seen to occur in the epidural space above and below the herniated disc. At surgery, they were found to correspond to dilated and congested epidural veins.     

不稳定型桡骨远端骨折的外固定器治疗

目的：探讨外固定器治疗不稳定型桡骨远端骨折的疗效。方法：对12例不稳定型桡骨远端骨折的患者采用改良AO外固定器治疗，术后随访5－8个月，根据骨折愈合情况和腕关节形态及功能情况，按Jakim评分结果评价治疗效果。结果：骨折愈合时间为6－8周，优良率为91％。结论：外固定器治疗不稳定型桡骨远端骨折具有良好的固定作用，能较好地防止骨折畸形愈合和保护腕关节功能。     

Efficacy evaluation of gadoteridol for MR angiography of intracranial vascular lesions

A phase III multicenter study was conducted in 89 patients with known intracranial vascular lesions to evaluate an extracellular gadolinium contrast agent, gadoteridol, for intracranial magnetic resonance (MR) angiography. The pre- and postcontrast MR angiograms of 82 patients were evaluated by the unblinded investigators and by two blinded readers (A and B) for visualization of lesions; arterial and venous anatomy; extent, size, and number of lesions; and disease classification. The unblinded readers indicated that lesions were visualized better on postcontrast images in the following categories: venous anatomy, 87 (81%) of 107 lesions; arterial anatomy, 43 lesions (40%); and extent or size of lesions, 38 lesions (36%). In 29 (35%) of 82 patients, the unblinded readers determined that enhanced MR angiography provided more diagnostic information than unenhanced MR angiography. The blinded readers determined that enhanced MR angiography provided more information for visualization of vascular anatomy in more than 60% of cases. The additional information provided with gadoteridol would have changed the diagnosis in nine (8%) of 107 lesions seen by the unblinded readers, 11 (12%) of 90 lesions seen by reader A, and three (3%) of 93 lesions seen by reader B. The results confirm that the use of gadoteridol improves the visualization of intracranial vascular lesions with MR angiography. The authors conclude that development of new postprocessing algorithms will improve the utility of contrast-enhanced MR angiography.