Phase-derivative analysis in MR angiography: Reduced Venc dependency and improved vessel wall detection in laminar and disturbed flow

A problem of current MRA techniques is the inability to accurately depict the vascular anatomy, particularly in areas of disturbed flow. Various reasons, such as intravoxel phase dispersion, saturation, temporal variations, and maximum intensity projection (MIP) nonlinearity, cause a wrong delineation of vessel boundaries. A phase contrast (PC)-based postprocessing operation, the phase derivative (PhD), is introduced to detect phase fluctuations indicating flow. Two-dimensional and three-dimensional angiographic reconstruction algorithms are presented. Mathematical formulas are derived to predict the effect of sampling to flow profiles and the effect on the PhD of these profiles. Numerical, phantom, and preliminary in vivo experiments demonstrate that PhD images do not suffer from phase wraps and allow a velocity dynamic range extension only limited by a differential phase change. It is also shown that PhD MIPs produce higher signal-to-noise ratios than conventional PC angiograms and give a better impression of the anatomy of (stenotic) vessels and of their diameters for both laminar and disturbed flow.     

The Lumbar Spinal Canal in Hypophosphataemic Vitamin D-resistant Rickets

Abstract: Lumbar spine radiographs of 77 adult patients with hypophosphataernic vitamin D-resistant rickets have been examined and measured in their anteroposterior and transverse dimensions. Comparison of these measurements with those of a group of normal individuals showed the HPR patient group to have narrower spinal canals in both diameters. No differences were found between males and females in either group. The lumbar spinal canal stenosis in adult HPR patients may make them more susceptible to spinal cord compromise from space occupying lesions within the canal, causing back pain and lower limb weakness for which surgical intervention may be indicated.     

Wingspan自膨式支架在症状性大脑中动脉狭窄中的应用

目的 探讨Wingspan支架成形术治疗症状性大脑中动脉水平段(M1段)狭窄的安全性和可行性.方法 回顾性分析32例经自膨式支架治疗的症状性大脑中动脉缺血反复发作、药物治疗无效的大脑中动脉狭窄患者的临床资料.本组男19例、女13例,平均年龄(49±19)岁.所有患者经过Gateway球囊预扩后,植入Wingspan自膨式支架.术后6个月对所有患者均进行电话或门诊随访,并建议所有随访患者进行经颅超声多普勒检查或血管造影检查,分析本组患者手术成功率、并发症以及临床疗效.结果 32例患者均成功植入支架,术前M1段狭窄率平均(76.5±15.4)%,支架植入后平均(19.3±9.2)%;球囊预扩引起1例颅内出血、1例M1段急性闭塞,无一例死亡.术后6个月随访无一例患者再发生缺血性神经事件;19例患者在术后6个月行经颅超声多普勒检查,结果显示血流速度正常;5例行血管造影.均显示支架段开通良好,8例患者拒绝影像检查.结论 采用自膨式支架对有症状的M1段狭窄进行成形术可行、安全,近期随访证实疗效确切,但长期疗效还需要进一步观察.     

彩超、增强磁共振动脉造影对颅外颈动脉狭窄的术前评估

目的 评价彩超、增强磁共振动脉造影(CEMRA)对颅外颈动脉狭窄的术前评估价值。方法 回顾分析了93例因颅外颈动脉狭窄而接受介入治疗患者的术前彩超、CEMRA检查结果。结果 超声检查可判断狭窄性质和狭窄程度，CEMRA能显示颈动脉全程，显示多发狭窄。但两者对狭窄程度都有过高评估的倾向，对斑块溃疡难以显示。结论 就目前彩超和磁共振机器的性能，尚无法替代DSA检查。必须有机地结合彩超、CEMRA和DSA检查，以多侧面、全方位地了解狭窄的颈动脉，制定合理的治疗方案。     

原发性肝癌致下腔静脉阻塞的介入治疗

目的研究介入治疗肝癌所致下腔静脉梗阻的疗效及方法。方法6例患者,临床主要症状有腹胀、腹壁静脉曲张和下肢浮肿等。均为肝右叶病变压迫侵蚀下腔静脉所致的狭窄阻塞。治疗方法采用先溶栓,而后球囊扩张和内支架植入。结果6例患者狭窄阻塞的下腔静脉均开通成功,下腔静脉血流通畅,压力由术前的4.0kPa(1kPa=7.5mmHg)降至2.1kPa,无严重并发症。结论采用介入方法开通由于肝癌所引起的下腔静脉狭窄阻塞,疗效肯定,可提高患者的生活质量,延长患者的生存时间。     

Physiologic Effect of Stent Therapy for Inferior Vena Cava Obstruction Due to Malignant Liver Tumor

Purpose To understand systemic the influence of stent therapy for inferior vena cava (IVC) obstruction due to advanced liver tumor. Methods Seven patients with symptomatic IVC obstruction due to advanced primary (n = 4) or secondary (n = 3) liver tumor were subjected to stent therapy. Enrollment criteria included high IVC pressure over 15 mmHg and the presence of edema and ascites. Z-stents were deployed using coaxial sheath technique via femoral venous puncture. Physiologic and hematobiochemical parameters were analyzed. Results All procedures were successful, and the stents remained patent until patient death. Promptly after stent placement, the IVC flow recovered, and the venous blood pressure in the IVC below the obstruction level showed a significant decrease from 20.8 ± 1.2 mmHg (mean ± SE) to 10.7 ± 0.7 mmHg (p < 0.01). Transient mild increase of right atrial pressure was observed in 1 patient. During the following week prominent diuresis was observed in all patients. Mean urine output volume in the 3 days before the stent therapy was 0.81 ± 0.09 l/day compared with 2.1 ± 0.2 l/day (p < 0.01) in the 3 days after. The edema and ascites decreased in all patients. The caval pressure change correlated well (r > 0.6) with the urine volume increase, and with the decreased volume of edema and ascites. The urine volume increase correlated well with the decrement of edema, but not with that of ascites. Improvements for various durations in the levels of blood urea nitrogen, serum creatinine, lactate dehydrogenase, fibrinogen, and platelet count were found (p < 0.05). These hematobiochemical changes were well correlated with each other and with the decrement of ascites. Two patients showed a low blood sodium level of 128.5 mEq/l after intensive natriuresis, and one of them died on day 21 with hepatic failure, which was interpreted as maladaptation aggravation. The mean survival time was 94.1 ± 34.1 days (mean ± SD), ranging from 21 to 140 days after stent treatment. Conclusion The stent therapy for IVC obstruction due to malignant liver tumors was followed by a series of physiologic and hematobiochemical consequences, most of them favorable but some possibly unfavorable. Rational interpretations and predictions of sequelae based on physiologic science including cardiology, hepatology, and nephrology would facilitate the best management of stent therapy for malignant IVC obstruction.     

Tracheobronchial foreign bodies in children: importance of accurate history and plain chest radiography in delayed presentation

AIM: To evaluate the factors associated with delayed diagnosis of foreign body aspiration (FBA) in children and to compare clinical, radiological and bronchoscopic findings in the patients with suspected FBA. MATERIAL AND METHODS: The medical records of 214 children who underwent bronchoscopy for suspected FBA were reviewed. The data were analysed in three groups: the patients with negative bronchoscopy for FBA (group I), early (group II) and delayed diagnosis (group III). RESULTS: The majority of the patients with FBA were between 1 and 3 years of age. Choking episodes, coughing and decreased breath sounds were determined in a significantly higher number of the patients with FBA. The plain chest radiography revealed radio-opaque foreign bodies (FBs) in 19.7% of all patients with FBA. Emphysema was more common in children with FBA. Clinical and radiological findings of pneumonia and atelectasis were significantly more common in the groups with negative bronchoscopy and with delayed diagnosis (p < 0.01). The FBs were most frequently of vegetable origin, such as seeds and peanuts. A significant tissue reaction with inflammation was more common in the delayed cases. CONCLUSION: To prevent delayed diagnosis, characteristic symptoms, signs and radiological findings of FBA should be checked in all suspected cases. As clinical and radiological findings of FBA in delayed cases may mimic other disorders, the clinician must be aware of the likelihood of FBA. Regardless of radiological findings, bronchoscopy should be considered in patients with an appropriate history.     

冠状动脉狭窄的16层螺旋CT造影检查

目的以常规X线冠状动脉造影为标准,评价16层螺旋CT（MSCT）无创性检查冠状动脉及诊断冠状动脉狭窄的价值。资料与方法65例临床初诊为冠心病,无冠状动脉成形术和搭桥术史的患者,在冠状动脉16层MSCT造影检查后,回顾性重建心电门控轴位图像,并采用容积成像（VR）、多平面重建（MPR）、曲面MPR、最大密度投影（MIP）等后处理方法,对所有冠状动脉及其分支进行重建,统计可供临床评价的、管径≥1．5mm的冠状动脉段,以选择性冠状动脉造影（SCA）为标准,对比分析MSCT诊断冠状动脉显著性狭窄（管腔平均直径缩小超过50％）的准确性。其中8例在检查前心率超过80次／min的患者使用了B受体阻滞剂。结果93％的冠状动脉节段和94％的冠状动脉主干可供评价,不能评价的主要原因分别为：心脏运动伪影（58％）,致密钙化（28％）和管腔显影不良（14％）。除外不能评价的冠状动脉,按节段和主干分类,MSCT诊断冠状动脉显著性狭窄的敏感性和特异性分别达到92％、98％和95％、97％。结论无需常规使用B受体阻滞剂,16层MSCT冠状动脉造影即可获得较好的图像质量用于诊断冠状动脉狭窄,是一种值得临床医师信赖的检查冠状动脉有无狭窄的非创伤性方法。     

介入治疗肝移植术后肝动脉并发症的初步经验

目的总结采用介入方法治疗肝移植术后并发肝动脉狭窄及血栓形成的初步经验。方法对4例肝移植术后并发肝动脉狭窄或血栓形成的患者行球囊扩张、经动脉溶栓、内支架置入术。结果1例肝动脉狭窄的患者经球囊扩张后临床症状缓解;3例肝动脉血栓形成患者经动脉溶栓后即刻肝动脉血流得到恢复;1例患者溶栓后3d发生吻合口出血,置入带膜支架,症状缓解,1d后肝动脉再次闭塞,2周后行第2次肝移植。结论采用介入方法对肝移植术后并发肝动脉狭窄或血栓形成的患者进行治疗是可行的,但必须谨慎实施,以避免发生出血等并发症。     

血管外膜应用西罗莫司对静脉移植物再狭窄的作用

目的探讨血管外膜应用西罗莫司对静脉移植物再狭窄的作用。方法 12条犬建立双侧股动脉自体颈外静脉旁路移植模型,随机喷涂西罗莫司的纤维蛋白胶(200 μg／2 ml)于一侧移植静脉外表面为实验组,对侧喷涂相同剂量蛋白胶为对照组。在术后2周和4周各取6条犬双侧静脉移植物制片,计算机图像分析系统测量和计算内膜厚度和截面积;检测管壁增殖细胞核抗原阳性细胞指数(PCNAI);扫描电镜观察内膜超微结构。结果术后2周和4周实验组的内膜厚度和截面积[(168．93±50．18)μm和(175．93±54．17)μm],[(1．08±0．20)mm2和(1．23±0．34) mm2]均较对照组[(201．83±43．57)μm和(224．83±45．92)μm)]和[(1．48±0．11)mm2和 (1．71±0．15)mm2]降低,P<0．05。术后2周后实验组血管壁PCNAI较对照组降低(14．78±1．89 和23．56±1．87,P<0．05),术后4周两组差异无统计学意义。扫描电镜下见术后2周实验组内皮覆盖较对照组良好,术后4周两组内膜已经完全内皮化。结论血管外膜局部应用西罗莫司对预防静脉移植物术后早期狭窄有良好的作用。