冠状动脉CT血管成像剂量降低技术的应用现状和进展

冠状动脉CT血管成像(CCTA)的辐射剂量在“后64层CT”时代仍得到广泛关注,各种剂量降低技术得到进一步发展,使得高端机型CCTA的辐射剂量显著降低.熟练掌握并综合应用不同的剂量降低技术,有效地降低管球曝光强度、缩短曝光时间和减少曝光范围,能够实现病人接受辐射剂量的最小化.就有关CCTA剂量降低技术及新进展予以综述.     

平原人急进高原最大做功能力测试

本文报道60名健康男性青年由海拔500m乘机到达海拔3680m,休息7天后,其最大做功量、最大摄氧量(Vo_2max)和最大心率(HRmax)等的变化规律。研究表明,平原人急进高原后,最大做功量由平原11109.1kgf.m降低到3967.7kgf.m,降低64.28％;Vo_2max由平原的2.673L/min降低到2.056L/min,降低23.07％;与最大做功量相比,高原低氧环境对Vo_2max的影响较小,仅以Vo_2max来评价平原人高原劳动能力是不全面的。受试者进入高原后,晨脉升高,HRmax降低,50％最大负荷运动心率升高,表明机体心力储备降低,做功效率降低。     

低剂量CT肺动脉成像技术进展

CT肺动脉成像(CTPA)已成为评价肺栓塞(PE)主要影像技术,筛查及多次CTPA复查PE疗效等使辐射剂量增加,因此低剂量CTPA日益受到重视。低剂量CTPA采取多种措施:降低管电流和管电压最为简单有效;大螺距扫描通过缩短扫描时间降低辐射剂量;缩小扫描覆盖范围可降低边缘器官的辐射;前瞻性心电门控在固定期相扫描及迭代重建算法选择性去除噪声等均可降低辐射。低剂量意识对于降低辐射至关重要。     

1周不同负荷运动对运动性血睾酮降低大鼠睾丸Leydig细胞胆固醇代谢的影响

目的:探讨运动性血睾酮降低的胆固醇代谢机制。方法:大鼠在经过5周间歇性负重游泳训练(TA组),造成运动性血睾酮降低的基础上,停训1周(TB组),继续训练1周:维持原负荷(负重5%体重,1组/日,TC组)、负荷量加倍(负重5%体重,2组/日,TD组)、负荷强度增加(负重6%体重,1组/日,TE组),检测大鼠Leydig细胞胆固醇代谢关键环节上的HMG-CoA还原酶、LDL-R、SR-BI及StAR mRNA表达。结果:(1)5周间歇性游泳训练后TA组大鼠血清睾酮显著降低,睾丸Leydig细胞LDL-R mRNA表达量显著升高,SR-BI、HMG-CoA还原酶、StAR mRNA表达量无显著变化。(2)与TA组相比,TB组血清睾酮水平显著升高,LDL-R mRNA表达量显著降低(P<0.01),SR-BI基因的表达量显著增加(P<0.01);TC组血清睾酮有进一步降低的趋势,但无统计学意义,LDL-R mRNA表达量显著降低(P<0.01),SR-BI、HMG-CoA还原酶、StAR mRNA表达量无显著变化;TD组血清睾酮显著降低(P<0.05),LDL-R、SR-BI、HMG-CoA还原酶和StAR mRNA表达量显著降低(P<0.01,P<0.05);TE组血清睾酮有进一步降低的趋势,LDL-R、SR-BI、HMG-CoA还原酶mRNA表达量均显著性降低(P<0.05,P<0.01),StAR mRNA表达量未见显著变化。结论:(1)Leydig细胞内胆固醇代谢障碍的发生具有阶段性特征;(2)Leydig细胞内胆固醇代谢障碍不是导致运动性血睾酮降低的起始原因,而细胞内HMG-CoA还原酶、LDL-R、SR-BI、StAR基因表达量降低会加速运动引起的血睾酮降低。     

老年人运动与营养需要研究进展

国内外的研究显示[1] ,老年以后 ,人体许多方面的机能有不同程度的降低。例如到 80岁 ,神经的传导速度降低 2 0 - 30 % ,最大耗氧量降低 4 0 %。而到 70岁时 ,肝肾功能只有 30岁时的 6 0 - 5 0 %。 70- 80岁老人的骨量 ,女性降低 30 % ,男性降低15 %。 6 5 - 75岁时 ,约有 4 0 %的老年人糖耐量降低 ,到 80岁时 ,这个数字增加到 5 0 % ,说明内分泌功能的降低。老年期机体的另一个突出变化是体成分的改变[2 ] ,肌肉力量在 70岁时约降低 30 % ,80岁时约降低 4 0 %。很多老年人体重还较高、体脂成分比例也更大。随着年龄的增加 ,去脂体重降低 ,…     

颞骨64排螺旋CT扫描剂量实验研究

目的 研究64排螺旋CT颞骨扫描剂量与电流、电压及图像质量的关系,探讨降低剂量扫描方法.材料与方法采用东芝64排螺旋CT,在电压分别为120 kV、100 kV及80 kV时,逐渐降低电流扫描,对头颅标本行颞骨扫描,直至图像质量很差时停止.比较CT剂量指数(CTDIvol)与电流、电压及图像质量的关系.结果 电压固定,CTDIvol与电流(mA)呈线性关系.降低mA,可以降低剂量,同时噪声标准偏差(SD)也增加,电流降到30 mA时,噪声SD 120～150,颞骨内精细结构仍能显示.CTDIvol与电压(kV),呈指数型曲线关系,电流较大时,电压降低少许,即可大幅度降低剂量.获得相同图像质量,儿童较成人可以用更低的剂量扫描.结论 64排螺旋CT颞骨扫描可以降低电流也可适当降低电压以降低X线辐射剂量.     

一种新型可应用于临床的微辐射平台——星光iDose~4

近年来,基于CT应用的逐渐增加,CT辐射风险口渐成为焦点话题,日本福岛核事件更是使辐射风险被公众广泛认知,如何有效降低CT辐射剂量愈来愈引起医学界的关注。Naidich于1990年首次提出低剂量的概念,即在其他条件不变的情况下,降低管电流来减低辐射,同时保证图像诊断要求。此后CT低剂量技术在临床上的应用迅速开展起来,多年来学者们研究出了很多的方法来降低CT辐射剂量,如降低管电流(mAs);增加螺距(Pitch);降低管电压(KV)等。     

葡萄残渣对体外瘤胃发酵与甲烷生成的影响

采用体外产气法研究了葡萄残渣对体外瘤胃发酵参数与甲烷的影响试验,结果表明:6%、12%添加组与对照组相比,总挥发性脂肪酸浓度显著降低(<0.05);12%添加组与对照组、6%、3%添加组相比,乙酸/丙酸比例显著降低(<0.05);6%、12%添加组与对照组相比,微生物蛋白合成量以及微生物合成效率均显著降低(<0.05);各添加组与对照组比较,显著降低了体外瘤胃培养24 h产气量中甲烷的比例(<0.05);按培养底物干物质计算,与对照组相比,6%、12%添加组显著降低了甲烷的生成量(<0.05).与对照组相比,12%添加组显著降低了体外饲料瘤胃干物质降解率(<0.05).6%、12%添加组与对照组比较,显著降低了体外饲料瘤胃粗蛋白降解率(<0.05).     

品管圈在降低产科住院产妇乳头皲裂发生率中的应用

目的:探讨品管圈活动在降低产科住院产妇乳头皲裂发生率中的应用效果.方法:成立品管圈小组,以"降低住院产妇乳头皲裂发生率"为活动主题,进行现状把握、目标设定、原因分析、对策拟定及实施等活动.评估实施品管圈活动的临床干预效果.结果:开展品管圈活动降低了住院产妇乳头皲裂发生率,从活动前的27.84％降低到活动后的7.87％,...     

多层螺旋CT低剂量扫描胸部的影像学研究

目的探讨将通过降低管电流或管电压来降低多层面螺旋CT扫描的X射线剂量的方式用于胸部,观察其影像图像质量的变化。方法用120kV/(200mA、100mA、50mA、20mA);200mA/(120kV、100kV、80kV);80kV/50mA对20例胸部主动脉弓上和膈上水平2个特定层面进行扫描。测量每例纵隔窗上相同的固定解剖结构点(皮下脂肪,椎体,肌肉)的CT值;对每例肺窗的影像图像进行5等级评分。结果纵隔窗的皮下脂肪、骨骼肌、椎体在降低管电流时的CT值变化没有统计学意义(P≥0.799,P≥0.803,P≥0.65);在降低管电压时,皮下脂肪、骨骼肌的CT值均降低,椎体的CT值增加,三者的CT值变化均有统计学意义(P≤0.0035,P<0.0001,P=0.012),肺窗的等级评分没有统计学意义(P=0.879,P=0.605)。当管电流降低到20mA或同时降低管电压和管电流(80kV/50mA)时肺尖肺窗的线性硬化伪影非常明显,有统计学意义(P≤0.001,P≤0.001)。结论降低管电压或同时降低管电流和管电压会改变影像图像的质量。用降低管电流的方式可降低X射线剂量,即用多层面螺旋CT低剂量扫描胸部是可行的,但至20mA后肺尖有线性硬化伪影。     

床旁纤维支气管镜引导经鼻气管插管抢救慢性阻塞性肺部疾病呼吸衰竭的临床应用

目的：探讨床边纤维支气管镜（简称纤支镜）引导下经鼻气管插管抢救慢性阻塞性肺部疾病（COPD）呼吸衰竭的临床价值。方法：总结48例喉镜经口插管和床旁纤维支气管镜引导经鼻气管插管所需时间、对生命体征影响、插管成功率、插管结束后并发症。结果：A组和B组插管所需时间差异无显著性（P〉0．05）。A组和B组插管结束后并发症（P〈0．01）。A组和B组插管成功率差异无显著性（P〉0．05）。A组和B组插管前后呼吸频率增加（P〈0．05）。A组和B组插管前后心率增加差异有非常显著性（P〈0．01）。A组和B组插管前后血压增加差异有显著性（P〈0．05）。A组和B组插管前后SPO2降低差异有非常显著性（P〈0．01）。结论：纤维支气管镜引导下经鼻气管插管抢救COPD呼吸衰竭，操作简单、快速、准确、安全，值得临床推广应用。     

Evaluation by ultrasound of traumatic rib fractures missed by radiography

Rib fractures are the most common (25%) injuries resulting from blunt chest trauma, and are usually revealed on radiographs. Radiography sometimes cannot show fractures, especially those in costal cartilages, except for densely calcified ones. Several authors have recently investigated the role of ultrasound in the detection of rib fractures. We conducted this study to investigate possible rib fractures with ultrasound, determine those overlooked on chest x-ray, and analyze the possible clinical predictors of these insidious rib fractures in minor or mild blunt chest trauma. A total of 20 patients with minor mild blunt chest trauma were enrolled into this study. All radiographs were reviewed by two radiologists who noted rib fractures or other complications. Ultrasonography was performed in the radiology department using a linear transducer by one radiologist. The costal cartilage normally appears relatively hypoechoic compared with the osseous rib. Fractures of the rib, costochondral junction, and costal cartilage were denoted by a clear disruption of the anterior echogenic margin. A total of 20 patients with normal radiological findings, but continuing symptoms were evaluated by ultrasound. The most common etiology of trauma was a fall, as seen in 60% of the patients. None of the rib fractures were identified radiographically. Sonography detected 26 rib fractures in 18 of 20 subjects at presentation. Sonography reveals more fractures than radiography and will reveal fractures in most patients presenting with suspected rib fracture.     

预处理对减少依托咪酯所致肌阵挛120例临床观察

目的：观察通过预处理对依托咪酯全麻诱导时肌阵挛的影响。方法：120例择期全麻患者随机分为3组：雷米芬太尼组、维库溴铵组和对照组,每组40例。观察各组全麻诱导时依托咪酯引起肌阵挛的例数,并记录肌阵挛的发生程度。结果：雷米芬太尼组出现3例肌阵挛（7.5%）,其中轻度1例,中度2例;维库溴铵组出现2例轻度肌阵挛（5.0%）;对照组出现30例肌阵挛（75.0%）,其中轻度15例、中度12例、重度3例。雷米芬太尼组和维库溴铵组肌阵挛发生率明显低于对照组（P〈0.01）,而雷米芬太尼组和维库溴铵组间比较差异无统计学意义。结论：通过雷米芬太尼和维库溴铵预处理均可减少依托咪酯全麻诱导所致的肌阵挛,而因二者对心血管系统的影响不同,使用维库溴铵预处理更利于心血管系统功能降低的患者。     

双神经弓式双端侧吻合治疗痛性指固有神经瘤

目的介绍一种治疗痛性指固有神经瘤的手术方法。方法2005年2月-2011年3月,巢湖紫晨手外科医院手外科中心采用双端侧吻合治疗指固有神经瘤11例11指。术中将神经瘤彻底切除直至正常神经束,对远、近端尺桡侧指固有神经分别进行远与远、近与近端一端吻合,形成远、近2条神经弓;测量两神经弓间距,取直径相近的前臂外侧皮神经,平分为两段,分别于神经弓的尺、桡侧开窗式端侧吻合。结果随访24．5—52个月,平均（38±2．5）个月。9例指疼痛完全消失,2年后未见复发;2例指自发性疼痛消失,但仍有轻度触痛,参照Burchiel疗效评定标准：优9指,良2指;优良率100％。感觉测定指标为s3～s4级,两点分辨觉为4．5—6．5mm。结论双神经弓式双端侧吻合的方法可有效治疗痛性指固有神经瘤,消除患指疼痛、恢复指腹灵敏性。     

Ilizarov外固定架分步延长法治疗儿童尺骨骨干续连症的疗效

 目的 探讨一种应用Ilizarov外固定架治疗儿童尺骨骨干续连症的方法及其疗效。方法 2009-02至2015-10,采用Ilizarov外固定架分步延长法,对29例尺骨骨干续连症患儿进行了矫治。通过定期门诊复查及拍摄患肢X线片,评估术后患肢畸形及功能改善情况。结果 患儿术后平均随访38个月,尺骨平均延长3.2 cm;1例延长过程中出现骨不连,通过调整延长速度后逐渐愈合;1例拆除外架后发生尺骨骨折,石膏固定后自行愈合。术后患儿腕关节、肘关节及前臂功能均得到改善。 结论 应用Ilizarov外固定架分步延长法治疗儿童尺骨骨干续连症效果明显,但术中要注意熟练操作,避免副损伤的发生,延长过程中要注意控制延长速度,做好各项并发症的预防。     

超声引导下注射凝血酶治疗医源性股动脉假性动脉瘤

目的:探讨超声引导下瘤腔内注射凝血酶治疗医源性股动脉假性动脉瘤的方法及其可行性和安全性.方法:6例患者因行股动脉穿刺于术后2～5 d发生6处股动脉假性动脉瘤,均在彩色多普勒超声定位下通过瘤腔内注射凝血酶进行治疗,治疗后即刻超声复查,并定期随访.结果:4例患者4处假性动脉瘤一次性注射凝血酶300～500 U后瘤腔即刻闭合,随访10～90 d,假性动脉瘤无复发.2例患者2处假性动脉瘤瘤体较大,第1次注射后于第3 d复发,行第2次注射后,假性动脉瘤无复发.其中1例患者出现一过性肢体栓塞临床表现,经观察后肢体栓塞临床表现消失,未特殊处理.6例患者均未出现过敏反应等并发症.结论:瘤腔内注射凝血酶治疗医源性股动脉假性动脉瘤是一种创伤小、有效、安全的方法,但操作时需注意瘤体的大小及凝血酶的用量.     

Comparison of SUVs Normalized by Lean Body Mass Determined by CT with Those Normalized by Lean Body Mass Estimated by Predictive Equations in Normal Tissues

Purpose

Standardized uptake values (SUVs) normalized by lean body mass (LBM) determined by CT were compared with those normalized by LBM estimated using predictive equations (PEs) in normal liver, spleen, and aorta using ¹⁸F-FDG PET/CT.

Methods

Fluorine-18 fluorodeoxyglucose (F-FDG) positron emission tomography/computed tomography (PET/CT) was conducted on 453 patients. LBM determined by CT was defined in 3 ways (LBM_CT1-3). Five PEs were used for comparison (LBM_PE1-5). Tissue SUV normalized by LBM (SUL) was calculated using LBM from each method (SUL_CT1-3, SUL_PE1-5). Agreement between methods was assessed by Bland-Altman analysis. Percentage difference and percentage error were also calculated.

Results

For all liver SUL_CTs vs. liver SUL_PEs except liver SUL_PE3, the range of biases, SDs of percentage difference and percentage errors were −0.17-0.24 SUL, 6.15-10.17 %, and 25.07- 38.91 %, respectively. For liver SUL_CTs vs. liver SUL_PE3, the corresponding figures were 0.47-0.69 SUL, 10.90-11.25 %, and 50.85-51.55 %, respectively, showing the largest percentage errors and positive biases. Irrespective of magnitudes of the biases, large percentage errors of 25.07-51.55 % were observed between liver SUL_CT1-3 and liver SUL_PE1-5. The results of spleen and aorta SUL_CTs and SUL_PEs comparison were almost identical to those for liver.

Conclusion

The present study demonstrated substantial errors in individual SUL_PEs compared with SUL_CTs as a reference value. Normalization of SUV by LBM determined by CT rather than PEs may be a useful approach to reduce errors in individual SUL_PEs.     

Chest-wall invasion by carcinoma of the lung: detection by MR imaging

Nineteen patients with bronchogenic carcinoma were studied by MR imaging to determine the presence of chest-wall invasion. All studies were carried out at 1.5 T, and the results were correlated with chest radiographs or CT scans. All MR studies were interpreted before surgery (13 cases) and without knowledge of the results of other radiologic studies. MR findings indicative of chest-wall invasion included a high-signal focus within the chest wall and/or chest-wall thickening with increased signal on spin-echo (SE) images having a repetition time of 2500 msec and an echo time of 50-100 msec (SE 2500/50-100). In one case, noncontour-deforming high-signal intensity within chest-wall musculature (but no other abnormality) was demonstrated on SE 2500/50-100 images. Coronal or sagittal imaging facilitated identification of tumor contiguity with extrathoracic structures in apical lesions. Contrast differences between normal and invaded chest wall on T2-weighted images were the most helpful in assessing chest-wall involvement. These preliminary observations indicate that MR imaging is useful in the evaluation of chest-wall invasion by carcinoma of the lung.     

Treatment of type D dural carotid-cavernous fistula by embolization followed by irradiation

Summary In a patient with dural carotid-cavernous fistula supplied by meningeal branches of both internal and external carotid arteries, particulate embolization of the meningeal branches of only the external carotid artery failed to cure the fistula. Subsequent radiation therapy achieved clinical and anatomical cure of the lesion.