Structural and functional changes in the cochlea following ultrasonic irradiation

Following ultrasonic irradiation of the cochlea cellular damage was observed within the hair cells of the organ of Corti and in the stria vascularis. The outer hair cells were more susceptible to damage than the inner hair cells. These immediate morphological changes did not occur when the intracochlear temperature was raised in the absence of ultrasound. Functional changes were determined from measurements of the cochlear microphonic response and the endolymphatic potential during ultrasonic irradiation. Cochlear irradiation produced a permanent depression in the positive E.P. In addition a depression in the microphonic response occured which comprised two distinct phases the slower of which was reversible. The permanent depression resulted from the combined effect of ultrasonic and thermal energy. The reversible change may be due to restriction in the energy available to the organ of Corti resulting from the influence of ultrasound on the stria vascularis.     

Ewing's Tumour of Rib Presenting as Chest Mass

A case of Swing's tumour of rib presenting as chest mass is reported. The role of computed tomography and chest ultrasound in evaluating such patients is discussed along with a brief review of literature.     

Two-dimensional diffraction scanning of normal and cancerous human hepatic tissue in vitro

A technique and associated equipment are described which investigate the acoustic signals backscattered from small tissue volumes and interrogated over a solid angle of transmitter/receiver positions. This two-dimensional diffraction technique produces acoustic scatter maps termed, by us “interferograms”, which are analysed to determine their usefulness in discriminating between normal, freshly excised liver tissue and cancerous tissue within the intact organ. The “interferograms” are collected at three different narrow-band frequencies and have been used in investigating 26 normal liver and 13 liver tumour samples. The preliminary results indicate that this novel technique has a 97% success in discriminating normal liver from tumour, compared to an 87% success achieved by two observers when scoring conventional sector B-scan images of the same tissue regions.     

Model studies of angular behaviour of acoustic backscatter

This note describes some studies of the relationship between filtered 180° backscattered amplitude and rotation angle, which has been suggested as a means for tissue characterisation. The studies include experimental measurements on simple linear and two-dimensional point targets, and theoretical computed results on both regular arrays and arrays with random displacement of the point scatterers.

The studies were carried out on models under favourable conditions with only small amounts of irregularity. They show that in certain situations neither the disposition and spacing of peaks in the curve of backscattered amplitude versus angle, nor a cross-correlation algorithm designed to detect the optimum scatterer-spacing in the model gave a good estimate of average scatterer spacing. The implication of this finding to clinical application is discussed.     

探讨高强度聚焦超声消融后残余子宫肌瘤组织转归的机制

目的分析超声消融对靶区外不同位点子宫肌瘤组织雌、孕激素受体以及芳香化酶的表达情况,探讨残余子宫肌瘤的转归的可能机制。方法采用MR引导下高强度聚焦超声(HIFU)肿瘤治疗系统消融8个子宫肌瘤,声功率400W,辐照时间60s,以MR检测靶区外子宫肌瘤组织的升温情况。治疗前取1cm×1cm子宫肌瘤组织为对照组。辐照完毕后取靶区外0.5cm、1.0cm、1.5cm处子宫肌瘤组织。以免疫组化法检测超声消融靶区边缘雌、孕激素受体及芳香化酶(P450酶)的表达,以Western-blot半定量检测P450酶蛋白表达水平。结果靶区周围肌瘤组织温度也有不同程度升高,并且靶区外位点的温度逐渐降低。与对照组比较,靶区外肌瘤组织雌、孕激素受体表达均无明显改变。免疫组化及Western-blot半定量结果显示P450酶蛋白在靶区外0.5cm、1.0cm的表达明显低于对照组(P<0.05)。结论超声消融部分子宫肌瘤后,在一定范围内的残余子宫肌瘤的生长会被抑制,其机制与温度影响P450酶的蛋白表达有关。     

比较脂质微泡与聚合物超声造影剂的微循环流变学

目的 探讨脂质微泡与高分子聚合物超声造影剂在大鼠肠系膜微循环中的流变学特征。方法 对10只大鼠经股静脉分别注射DiI标记的脂质微泡和高分子聚合物超声造影剂,通过倒置荧光显微镜观察两种不同造影剂在大鼠肠系膜微循环中的运动情况;比较注射前后小动脉、小静脉及毛细血管内径的变化,测定红细胞与两种造影剂在微循环内的流速。结果 注射后两种造影剂在大鼠肠系膜微循环内均可随血流移动,仅见少量脂质微泡短暂滞留。注射造影剂前后小动脉、小静脉及毛细血管内径无明显改变(P>0.05);两种造影剂在微循环内的流速与红细胞相似,差异无统计学意义(P>0.05)。结论 脂质微泡和高分子聚合物超声造影剂具有与红细胞相似的微循环流变学特征,均可作为红细胞示踪剂。     

声辐射力弹性成像:弹性成像的新发展

弹性成像作为一种重要的组织定征手段在过去20年里成为研究热点。传统的静态/准静态弹性成像难以从体外对体内通过机械方法进行有效施压,近年来研究者专注于新的远程"触诊"手段,即声辐射力弹性成像。本文对三种主要声辐射力弹性成像方法,即谐波运动成像、脉冲声辐射力成像和剪切波弹性成像的研究进行综述。     

连续周围神经阻滞用于术后镇痛的研究进展

连续周围神经阻滞术后镇痛效果好,副作用少,能够有效地缓解术后疼痛,促进手术后功能恢复,而得到越来越广泛的应用。近年来,神经刺激器、超声引导下定位技术的出现,使得连续周围神经阻滞定位更加准确,技术日趋完善,而对于局部麻醉药的选择、药物浓度等的相关研究使这一技术更加安全,有效。