Caudal block has much advantages such as simple operation,less complications,obvious effect,flat and low anesthesia.For those reasons,caudal block is widely used in pain treatment and clinical anesthesia.The traditional way of sacral canal anesthesia is based on osseous marks.However,because of variable anatomical structure in sacral canal and the sacral horns,the traditional method has many defects.In recent years,as a new operation method,caudal block under the guidance of ultrasound has began to be applied gradually.The advantages,application progresses of this method were reviewed in this paper.

Objective To investigate how many probably benign lesions on ultrasound(US) fulfilled the published criteria and to evaluate how clinical and personal factors influenced the categorization of breast lesions.Methods A total of 487 lesions in 487 women with more than 12 months follow-up after the initial category 3 assessment on US were included.The initial US images were retrospectively reviewed according to previously published criteria,and evaluated several factors that could influence the characterization of breast lesions in clinical practice such as age,multiplicity,palpability,radiologist 's experience,and lesion size.Results Of 487 lesions,479 (98.36%) were benign and 8 (1.64%) were malignant.Of 487 lesions,203(41.68%) including 8 malignancies were reassessed as category 4.If strict criteria had been applied at initial US examination,the positive biopsy rate would have been only 3.94% (8/203) and 96.06% (195 of 203) biopsies would have been unnecessary.Lesions in women 40 years or older and multiple lesions were more frequently reassessed as category 4 (P = 0.008 and P = 0.006,respectively).The presence of palpability,lesion size,and the radiologist 's experience did not significantly influence the categorization of breast lesions on US.Of 487 probably benign lesions,41.68 % could be classified as category 4 lesions when strict criteria were applied in initial practice.Conclusions The multiplicity of the lesion and the patient 's age were found to have a significant influence on the classifcation of probably benign solid masses.

Objective To test using musculoskeletal ultrasound (MSUS) to observe uncovertebral joints (UJs) and to explain the ultrasound images of UJs and their adjacent tissues,especially the vertebral artery (VA).Methods MSUS was used first with human skeletons and cadavers to localize the UJs and VA on the MSUS images with the aid of implanted needles.MSUS was then used with a patient clinically diagnosed with cervical spondylosis of the vertebral artery type (CSA) to detail the image of a normal UJ and its relationship with the adjacent tissues,especially the VA.Whether there was a lateral spur from the uncinate process (UP) was assessed to try to establish a method for measuring osteophytes.Results During the examination the patient was in supine,the neck was elevated 15cm with a pillow and was at 45 degrees of rotation to the contralateral side.The probe was placed at the medial border of the sternocleidomastoid muscle.When the longitudinal section of the common carotid artery was shown,the probe was slowly moved laterally until the VA first appeared,and then was moved up along the VA.Once the VA entered the transverse foramen,moving the probe slightly allowed the UJ behind the VA to be seen between two transverse processes.The UJ thus lies between two transverse processes,that is,between the lateral margins of two vertebral bodies and outside the intervertebral disc.The echo of the lateral border of the UP is on a straight line with the echo of the lateral margin of the vertebral body,with the VA in front of the line.It was noticed that the image of a UP with lateral osteophyte formation crossed the line and reached closer to the VA.The transverse diameter of the UJ was measured as the distance from a line cutting the lateral cortical margin of the cervical vertebra to the outer cortical margin of the lateral UP.Conclusion MSUS can clearly show the UJ and its adjacent tissues,especially the VA.It can be used to assess and measure UJs with lateral osteophyte formation.

Objective To prepare a kind of new lipid perfluorooctylbromide(PFOB) nanoparticles and to explore its potential application as an ultrasound contrast agent. Methods Lipid PFOB nanoparticles were prepared by microfluidization techniques. The morphology and distribution were observed with optical microscope and transmission electron microscope. Particle size and electric potential were determined with Malvern laser light scattering analyzer. Twelve normal Wistar rats were performed directly contrast imaging after injection of PFOB nanoparticles via caudal vein. Vital signs of the rats were monitored during the whole study. And eehogenie intensity of the liver was dynamically quantified through DFY ultrasound quantified analysis system. The mechanism of enhancement was studied by the frozen sections of rat's liver and spleen. Results The nanoparticles size and distribution were highly uniformed. The grey scale ultrasound imaging of the rat's liver and spleen were enhanced by PFOB nanoparticles. Ten seconds after PFOB nanoparticles injected,enhancement of liver began, the peak time was approximately 3 - 4 min, the duration of contrast enhancement was nearly up to 1 h, The enhancement of spleen was more significant and the duration was much longer. No abnormal changes of the rat's vital signs appeared during the study. Frozen sections suggested that PFOB nanoparticles accumulated in the liver and spleen was the potential mechanism of enhancement. Conclusions This novel and safe lipid PFOB nanoparticles could make prolonged enhancement of rat's liver and spleen,which has a good potency for ultrasound application.

Objective To study the feasibility of the Fe3O4-loaded lipid perfluorooctylbromide nanoparticles (Fe3O4-PFOB) for enhanced ultrasound imaging.Methods The Fe3O4-PFOB nanoparticles,incubated with RAW264.7 macrophage cells,were monitored by microscope and ultrasound.Twelve SD rats were randomized into two groups,Fe3O4-PFOB group and PFOB group.Ultrasound imaging of rats' liver was performed before and after intravenous injection of the contrast agents.The liver echogenic intensity was quantified by DFY ultrasound quantified system analysis.Results Incubation of the Fe3O4-PFOB nanoparticles with macrophages resulted in the uptake of Fe3O4-PFOB by macrophages.Macrophages loaded with Fe3O4-PFOB exhibited enhanced echogenicity in vitro.In in vivo imaging,Fe3O4-PFOB produced better and prolonged ultrasound enhancement of rats' liver compared to PFOB nanoparticles.Conclusions Fe3O4-PFOB nanoparticles could enhance ultrasound imaging and may potentially serve as a multimodal probe for ultrasound,CT and MR imaging.

Objective To investigate the size and diversification of peripheral nerve measured by high frequency ultrasound in di-abetic peripheral neuropathy patient .Methods The endings of the medial branch of deep peripheral nerves(DPN) were interrogated by high frequency ultrasound and nerve electrophysiology ,and the nerve conduction characters were studied in a cohort of 150 clini-cally diagnosed diabetic peripheral neuropathy patients and a control group of 100 healthy volunteers .At the sametime these cases underwent electrophysiological examination .Results Distinct echoic appearances were consistently detected between the DPN nerves of diabetic peripheral neuropathy patients and healthy volunteers .The sensitivity rate of high frequency ultrasound and nerve electrophysiological examination in diagnosis of diabetic peripheral neuropathy were 91 .33% and 74 .67% ,and the specificity rate were 91% and 82% .Conclusion High frequency ultrasound may play a role in the diagnosis of diabetic peripheral neuropathy .

Objective To prepare the multi-functional ultrasound contrast agents,which were investigated for ultrasound(US)/MR dual-mode imaging and high-intensity focused ultrasound(HIFU)synergism in vitro.Methods Double emulsion method was used to prepare the superparamagnetic iron oxide(SPIO)-loaded PLGA microcapsules(s-PLGA),and its morphology,size,Fe3O4 loading capacity were assessed.Then,the prepared s-PLGA microcapsules with different concentrations were applied to perform ultrasound and MR imaging in vitro.In addition,the degassed bovine liver in vitro was directly injected into 200 μl s-PLGA in saline(0.5 mg Fe/ml)just before HIFU ablation,the saline(200 μl)and pure PLGA (200 μl)were employed for control.After HIFU ablation,the volume of coagulated tissue irradiated by HIFU was calculated.Results The s-PLGA microcapsules were observed with regular spherical morphology and its average size was(885.6 ± 133.2)nm.In vitro,the s-PLGA showed hyperechogenicity in US imaging and MR negatively enhanced effeet in T2WI,the volume of coagulated tissue irradiated by HIFU after local injection of s-PLGA was larger than that of saline and pure PLGA(P＜0.05).Conclusions The prepared s-PLGA microcapsules are successfully acted as dual-mode biological imaging contrast agents for ultrasound and MR imaging and HIFU synergism in vitro.

Objective To prepare a kind of superparamagnetic iron oxide (SPIO) and doxorubicin loaded multifunctional polymer microbubbles (MPMBs),and to explore its potential application as an ultrasound(US)/magnetic resonance (MR) imaging contrast agent in vitro.Methods The MPMBs and normal polymer microbubbles (PMBs) were made by double emulsion and freeze-drying methods.The physical property,drug encapsulation efficiency and the drug-loading efficiency of MPMBs were determined,and the release property and US/MR imaging enhancement of MPMBs were observed.Results The MPMBs had a regular shape and narrow size distribution.The drug encapsulation efficiency was (60.20±2.69) ％,and the drug-loading efficiency was (6.02 ± 0.27) ％.The in vitro release experiment showed that ultrasound can promote the release of doxorubicin in MPMBs.US imaging in vitro showed that the enhancement of MPMBs was better than PMBs,and MR imaging in vitro conformed that MPMBs could well enhance MR imaging.Conclusions The MPMBs is a multifunctional contrast agent with the treatment function as well as US/MR dual-mode imaging enhancement effect.

Objective To prepare the Fe3O4 loaded polymer microspheres(Fe3O4/PLGA),and to investigate the influence of Fe3O4/PLGA combined with high-intensity focused ultrasound (HIFU) on rabbits bearing breast tumor.Methods Double emulsion method were utilized to prepare the Fe3O4/PLGA.14 days after implantation of VX2 tumor in breast,32 rabbits were randomly divided into four equal groups.In group Ⅱ,Ⅲ,and Ⅳ,the rabbits received a percutaneous injection of 0.5 ml saline,PLGA,and Fe3O4/PLGA microcapsules solution into breast tumor at 3,6,9,12 dots,about 3 mm around the tumor respectively,and massaged for 1 min before receiving HIFU ablation,while HIFU group received HIFU ablation only.HIFU ablation parameters were the same:ablated-dot mode,acoustic power 150 W,exposure duration 5 s.After HIFU ablation,the volume of coagulative necrosis was calculated,HE staining,TEM and immunohistochemical examination of PCNA were performed to detect the structure changes of the targeted tissue caused by HIFU ablation.Results The volume of coagulative necrosis caused by HIFU ablation was substantially larger and the positive index of PCNA was lower in the necrotic region after the injection of Fe3O4/PLGA microcapsules compared to the group without injection agents,the group of saline and the group of pure PLGA microspheres under the same irritation(P ＜0.05).Pathological examination demonstrated the targeted tissue was destroyed severely,Fe3O4 nanoparticles were seen depositing in residual tumor cells under TEM.Conclusions The self-made Fe3O4/PLGA microspheres can effectively enhanced the biomedical effect of HIFU surgery on rabbits bearing VX2 breast tumor.

ObjectiveTo study the optimal power of self-made polymeric microcapsules with liquid perfluorocarbon enhancing high intensity focused ultrasound (HIFU) ablation of normal bovine in vitro and the treatment efficacy of HIFU ablation of normal rabbit liver in vivo.Methods The experiment was divided into two parts:the first part was HIFU ablation of bovine in vitro:The bovine was injected different drugs before HIFU ablation to find the optimal power and treatment time.It was divided into four groups:①HIFU + 0.9％ NaCl(NACL) group; (② HIFU + poly( lactic-co-glycolic acid) (PLGA) group; ③ HIFU + perfluorohexane(PFH) group; ④ HIFU + PLGA + PFH group; The second part was HIFU ablation of normal rabbit liver.Similarly,It was also divided into four groups as above.Each group was undergone HIFU ablation with same parameters after ear vein injection of drug.Then the ultrasonographic changes and its value,and the actual situation of liver damage in target areas of each group were observed and compared before and after the ablation area.ResultsIn experiments of vitro bovine,gray scale changes and coagulation necrosis could be seen in the liver in group 2,3,4 with HIFU power of 150 W and treatment time of 2 s.In experiment of normal rabbit liver,the average gray-scale of group 3 and 4 were larger than that in group 1 and 2,the difference was statistically significant (P ＜0.001),and its gray change area gradually reduced with time elapsed.While there was no statistically significant difference between group 3 and 4 ( P ＞0.05).In pathological specimens,there was no significant liver damage in group 1 and 2.There was hemorrhagic necrosis and white coagulation necrosis in group 3 and 4.Conclusions The polymeric microcapsules with liquid perfluorocarbon can effectively enhance the efficacy of HIFU ablation and be used as a good synergist for HIFU.