低剂量CT肺动脉成像的实验研究

Objective To investigate the feasibility of reduced radiation dose for CT pulmonary angiography (CTPA) and the possible lowest radiation threshold by a phantom study.Methods The CT value difference between air within the trachea and the extracorporeal background region was measured in132 consecutive patients.A noise-measurement phantom and a pulmonary embolism (PE) phantom were made of phenol-formaldehyde, and both phantoms and a water phantom were scanned with standard and lower radiation doses as follow: 280, 200, 160, 100, 90, 80, 70, 60, 50, 40, 30, 20, 15, and 10 mA respectively, at a fixed voltage of 120 kVp.Standard and soft tissue algorithms were used to reconstruct the images.Three experienced doctors independendy evaluate the image quality and the efficiency of detecting PE of the images with various doses.The Pearson correlation analysis, two-tailed paired t test, ANOVA, and Kappa test were employed for the statistical analysis.Results The CT value difference between air within the trachea and the extracorpereal background region in 132 consecutive patients ranged from 20.00 to 55.00 HU, which had a positive correlation with weight[(64.99±11.86) kg], weight-height ratio [(38.71±6.13) kg/m], and BMI[(23.11±3.38) kg/m2](r=0.228,0.374,0.449 respectively; P <0.01).The image noise level with soft-tissue reconstruction algorithm[(16.55±9.08), (16.42±9.40) HU]was significantly lower than that of the image with standard reconstruction algorithm[(22.43±11.25),(21.99±11.67) HU](F=4.316, P < 0.05).The image noise level with soft-tissue reconstruction algorithm at 100 mA was similar to that of the images with standard reconstruction algorithm at 280 mA, and the signal-w-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the image of PE phantom was 23.05 and 20.52 respectively, without any impairment in detectability of embolus.The image noise level with soft-tissue reconstruction algorithm at 60 mA was similar to that of the image with standard reconstruction algorithm at 160 mA, while the SNR and CNR was 18.01 and 15.97 respectively, also with acceptable detectability of embolus.When the tube current was reduced below 30 mA, the image quality decreased significantly, with the SNR and CNR was lower than 12.36 and 10.95 respectively, and the detectability of embolus was degraded.The consistency of the image quality grading by 3 observers was excellent(K=0.807,0.712,0.904 ,respectively; P < 0.01).Conclusions The 100 mA may potentially be the ideal low dose tube current setting, with radiation dose only equal to 36% of 280 mA (standard dose).The 30 mA may possibly be a minimum radiation dose for detecting PE.The soft-tiasue reconstruction algorithm was favorable in preserving the SNR when the radiation dose was reduced.     

抗CEA人/鼠嵌合抗体rch24在裸鼠人结肠癌模型中的放射免疫显像

笔者探讨^125I标记抗癌胚抗原(CEA)人／鼠嵌合抗体rch24在裸鼠人结肠癌模型中放射免疫显像(RII)及其用于结肠癌定位诊断及导向治疗的可行性，现报道如下。     

早期食管癌的X线分析

食管癌是一种常见恶性肿瘤,及早认识和掌握早期食管癌的X线表现和检查方法,可以提高患者生存质量。笔者现将我院资料完整的10例患者结合文献讨论如下。1材料与方法10例患者均为男性,年龄33~69岁。主要症状为吞咽食物时偶有疼痛,食物通过时有停滞异物感,4例无症状,2例为普查时发     

RNA干涉抑制肺癌细胞DNA甲基转移酶1(DNMT1)的表达

目的：通过抑制肺癌细胞DNA甲基转移酶1(DNMT1)的表达，从而部分恢复抑癌基因的表达。方法：采用RNAi技术来抑制DNMT1的活性。应用体外转录的方法，共合成了5个针对DNMT1不同靶位的siRNA序列，并转染人肺癌细胞NCI-H157。采用MSP-PCR、COBRA等方法对抑癌基因RASSF1A进行甲基化分析，半定量RT-PCR检测DNMT1 mRNA的敲降与RASSF1A基因的表达。结果与结论：5个靶位的siRNA序列中有两个靶位能够有效地抑制DNMT1的表达，且呈剂量依赖效应。人肺癌细胞NCI-H157中抑癌基因RASSF1A发生了高度甲基化，在抑制DNMT1活性后，RASSF1A基因去甲基化而恢复表达。     

血栓心脉宁胶囊对大鼠实验性心肌梗死的保护作用

 目的研究血栓心脉宁胶囊对大鼠实验性心肌梗死的保护作用.方法通过结扎大鼠左冠状动脉前降支(Leftanterior descending coronary artery,LAD)建立急性心肌梗死模型,观察血栓心脉宁胶囊对实验性心肌梗死的影响及其作用机制.结果血栓心脉宁胶囊2、4g/kg灌胃7 d,对急性心肌梗死24h大鼠,可明显缩小梗死面积,降低血清CK、LDH活性及脂质过氧化物(Lipid peroxidation,LPO)含量,提高超氧化物歧化酶(SOD)活性,并能使血浆血栓素A2(TXA2)水平明显下降,前列环素(PGI2)水平及PGI2/TXA2比值明显增高,亦可使心肌梗死区游离脂肪酸(FFA)含量明显降低.结论血栓心脉宁胶囊对急性心肌缺血具有明显保护作用,可能与其增强抗氧化酶活性,减少自由基对心肌的氧化损伤,纠正心肌缺血时FFA代谢紊乱及PGI2/TXA2平衡失调等机制有关.     

外固定架治疗股骨髁上Schatzker Ⅳ型骨折8例

股骨髁上Sehatzker Ⅳ型骨折属于膝关节内粉碎性骨折,如复位、固定不当,将严重影响膝关节功能,造成病残。我科自2002年8月～2003年2月共收治8例,采用切开复位、Bastianni外固定架固定(必要时结合螺钉、钢丝捆扎固定),术后石膏托保护,辅以早期适当患肢功能锻炼,均取得明显效果。     

氧化应激诱导神经细胞凋亡与c-Myc、Fas-FasL、核因子-κB关系的研究

目的　探讨氧化应激诱导神经细胞凋亡与c -Myc、Fas -FasL、核因子 -κB(NF -κB)蛋白表达的关系。　方法　将分离培养的新生SD大鼠大脑皮质神经细胞分为 :A组 (对照组 )、B组 (缺氧处理 )、C组 (低浓度H2 O2 处理 )、D组 [缺氧 +超氧化物歧化酶 (SOD)处理 ]、E组 (H2 O2 +SOD处理 ) ,利用琼脂糖凝胶电泳、末端脱氧核苷酸介导的X -dUTP缺口末端标记法 (TUNEL)、流式细胞仪测定细胞凋亡 ,免疫组织化学方法 (SP法 )测定细胞c -Myc、Fas -FasL、NF -κB蛋白表达。结果　B组和C组神经细胞凋亡率分别为A组的 6倍和 8倍 (P <0 .0 1) ;A组c -Myc、Fas-FasL、NF -κB阴性表达 ,其余各组均有阳性表达 ;SOD在降低B组和C组细胞c-Myc、Fas-FasL、NF -κB表达强度的同时 ,细胞凋亡率也随之降低。　结论　氧化应激诱导神经细胞凋亡可能与NF -κB的激活 ,启动凋亡相关基因c -Myc、Fas -FasL有关。     

肠缺血的CT评价

肠缺血的临床诊断和放射学诊断仍是临床医生和放射科医生面临的一个难题.重点介绍了肠缺血的病因、CT检查技术及常见征象.     

经尿道膀胱镜下前列腺电切术的围术期护理

前列腺增生(BPH)是老年男性常见病[1],男性自35岁开始出现前列腺不同程度的增生,50岁以后会出现临床症状,且发病率随年龄的增长而增高,当组织增生严重,压迫尿道而出现明显症状时,以手术治疗为主。我科于2006年1月~6月开展经尿道膀胱镜下前列腺电切术25例,手术效果较好,现将该手     

丙泊酚和七氟醚对术后睡眠质量的影响

目的观察丙泊酚或七氟醚对全麻术后睡眠质量及褪黑素分泌的影响。方法选择行妇科腹腔镜手术的患者120例,年龄18～49岁,BMI 18.5～25 kg/m~2,ASAⅠ或Ⅱ级,采取随机数字表法分为两组(n=60):丙泊酚组(P组)和七氟醚组(S组)。两组采用相同药物麻醉诱导; P组麻醉维持采用丙泊酚靶控输入4~12 mg·kg~(-1)·h~(-1),间断静注舒芬太尼0.2μg/kg、顺阿曲库铵0.1 mg/kg,维持BIS 40～60;S组麻醉维持采用七氟醚吸入MAC 1.0～1.3,间断静注舒芬太尼0.2μg/kg、顺阿曲库铵0.1 mg/kg,维持BIS 40~60。观察术前1 d及术后1、3、7、30 d患者的匹兹堡睡眠质量指数(PSQI)及晨尿硫酸褪黑素浓度。结果与术前比较,术后1、3 d P组PSQI明显升高,术后1 d S组PSQI明显升高(P0.05)。术后3 d S组的PSQI明显低于P组(P0.05)。与术前比较,术后1、3 d P组褪黑素浓度明显降低(P0.05);术后1 d S组褪黑素浓度明显降低(P0.05)。术后3 d S组褪黑素浓度明显高于P组(P0.05)。结论丙泊酚和七氟醚对全麻术后睡眠质量都有明显影响,但七氟醚对睡眠质量的影响较丙泊酚短暂。