智能最佳管电压扫描联合自动管电流调节技术降低成人胸部CT扫描辐射剂量

目的 探讨智能最佳管电压扫描(CARE kV)联合自动管电流调节(CARE Dose 4D)技术降低胸部CT扫描辐射剂量的价值。方法 将114例接受胸部CT 检查的患者随机分为2组,A组(50例)同时开启CARE Dose 4D及CARE kV,B组(64例)只开启CARE Dose 4D进行扫描,比较2组图像质量(平均CT值、噪声、SNR、CNR、主观评分等)及辐射剂量。结果 与B组相比,A组CT剂量加权指数(CTDIvol)减少约30.29%,剂量长度乘积(DLP)减少约30.41%,有效剂量(ED)减少约30.36%(P均<0.05)。A组图像噪声高于B组,差异有统计学意义(P<0.05),而2组平扫、增强图像除B组脊柱后方肌肉SNR高于A组(P<0.05)外,平均CT值、SNR、CNR差异均无统计学意义(P均>0.05),图像质量评分均在4.5分以上,病变检出率差异无统计学意义(P均>0.05)。结论 胸部CT扫描时,联合使用CARE kV和CARE Dose 4D技术,可获得优质图像,并降低辐射剂量。     

低电压自动管电流调节技术在上腹部增强CT扫描中的应用

目的 探讨低电压自动管电流调节(ATCM)技术在上腹部增强CT扫描中的价值。方法 将腹围<90 cm的100例患者随机分为2组,观察组(n=50):管电压100 kV,ATCM,动、静脉期参考管电流250、230 mAs。对照组:管电压120 kV,ATCM,动、静脉期参考管电流为210、190 mAs。测量并对比两组图像噪声、肝脏和胰腺SNR、肝脏-竖脊肌和胰腺-竖脊肌CNR、腹主动脉CT值、腹主动脉SNR、腹主动脉-竖脊肌CNR、静脉期容积CT剂量指数(CTDlvol)、剂量长度乘积(DLP)及有效剂量(ED)。结果 两组图像噪声、肝脏SNR、胰腺SNR、腹主动脉CT值、CTDIvol、DLP、ED比较,差异均有统计学意义(P均<0.05);腹主动脉SNR、腹主动脉-竖脊肌CNR、肝脏-竖脊肌CNR、胰腺-竖脊肌CNR、腹腔干三维分支评分及血管清晰度评分、轴位图像主观评价比较,差异均无统计学意义(P均>0.05)。结论 低管电压、ATCM上腹部增强CT扫描可降低辐射剂量,提高动脉血管显影程度,可满足诊断要求。     

Flash双源CT智能最佳管电压技术在小儿中耳胆脂瘤面神经管裸露中的应用

目的 评价高分辨率CT(HRCT)智能最佳管电压技术(CARE kV技术)在中耳炎患儿颞骨检查中对降低辐射剂量和显示面神经管裸露的应用价值。方法 收集中耳炎患儿(2~4岁)176例;按就诊先后顺序分为A组88例,采用CARE kV技术行颞骨HRCT扫描,B组88例,常规颞骨HRCT扫描。比较两组中耳胆脂瘤、面神经管裸露、HRCT图像质量及辐射剂量情况,并进行统计学分析。结果 A、B两组中耳胆脂瘤发生率[59.09%(52/88)vs 64.77%(57/88)]差异无统计学意义(χ²=0.020,P=0.887)。术前HRCT诊断中耳胆脂瘤的准确率两组间差异无统计学意义[96.15%(50/52) vs 96.49%(55/57),χ²=0.199,P=0.639]。A、B两组术前HRCT诊断面神经管裸露发生率分别为29.54%(26/88)和31.82%(28/88),术中观察面神经管裸露发生率分别为27.27%(24/88)和28.41%(25/88),两组间术前HRCT诊断及术中观察面神经管裸露发生率差异均无统计学意义(χ²=0.978、χ²=0.440,P均>0.05)。鼓室段面神经管裸露发生率最高(25/49,51.02%),迷路段最低(5/49,10.20%)。两组中,前膝段面神经管裸露长度术前HRCT与术中测量值差异有统计学意义(P均<0.05),其余各段差异均无统计学意义(P均>0.05)。两组间CT平均值、噪声(SD)、SNR、CNR差异无统计学意义(P均>0.05)。两组间剂量长度乘积(DLP)、有效剂量(ED)差异均有统计学意义(P=0.039、0.028)。结论 小儿颞骨HRCT智能最佳管电压技术能准确诊断面神经裸露,同时保证图像质量并有效降低辐射剂量。     

低管电压低碘含量对比剂上腹部增强CT检查

目的 探讨低管电压低碘含量对比剂上腹部增强CT检查的应用价值。方法 选取100例接受上腹部增强CT扫描患者,随机分为A组（管电压120 kVp、碘含量300 mgI/ml）、B组（管电压120 kVp、碘含量270 mgI/ml）、C组（管电压100 kVp、碘含量300 mgI/ml）及D组（管电压100 kVp、碘含量270 mgI/ml）,各25例;均采用40%ASiR算法和FBP算法混合图像重建。测量并分析各组门静脉期图像相同部位CT值、CNR、图像噪声、容积CT剂量指数（CTDIvol）。按4分制对所得图像进行总体图像质量评价,并进行组间比较。分析CT诊断与病理结果的符合率。结果 D组与A组比较,腹主动脉CT值、肝实质CT值、CNR_腹主动脉、CNR_肝实质、噪声差异均无统计学意义（P均>0.05）。A、B、C、D组CTDIvol分别为15.73±5.59、15.34±4.20、12.57±2.55、11.23±2.57,D组与A组比较差异有统计学意义（P<0.05）。4组CT诊断符合率分别为95.45%、90.00%、90.48%、90.91%。4组图像主观评分一致性良好。CT诊断符合率分别为95.45%、90.00%、90.48%、90.91%（P>0.05）。结论 采用低管电压（100 kVp）结合低碘含量（270 mgI/ml）对比剂行上腹部增强CT检查,所得图像质量符合诊断要求,且可降低X线辐射剂量。     

低管电压与低流速对比剂联合迭代算法在下肢动脉CTA中的应用

目的 探讨低流速对比剂、低电压扫描结合迭代重建算法在下肢动脉CTA检查中的应用价值。方法 收集60例接受双下肢动脉CTA检查者,将其随机分为两组、各30例,实验组:采用低管电压(80 kV)扫描,对比剂注射速率3.3 ml/s,迭代算法重建图像;对照组:采用常规管电压(120 kV),对比剂注射速率5.0 ml/s,使用滤波反投影法进行图像重建。扫描结束后记录容积剂量指数(CTDI)和剂量长度乘积(DLP)。测量腹部至小腿8个ROI及周围肌肉组织的CT值和标准差(图像噪声),计算CNR及SNR,并对图像质量进行评分。比较2组的辐射剂量、碘注射量、血管CT值及图像质量。结果 实验组的CTDI和DLP分别为(3.57±0.64) mGy和(429.26±97.60)mGy·cm,对照组分别为(7.23±0.86)mGy、(918.15±173.53)mGy·cm,二者差异有统计学意义(P均<0.001)。实验组平均碘注射量为(22.49±2.03)g,对照组(33.48±2.97)g,差异有统计学意义(t=2.58,P<0.05)。实验组8个ROI的平均血管CT值和图像噪声均高于对照组,差异有统计学意义(P均<0.05)。两组间CNR、SNR和图像质量主观评分差异无统计学意义(P均>0.05)。结论 采用80 kV管电压、3.3 ml/s对比剂注射速率联合迭代算法行双下肢动脉CTA检查,能够在保证图像质量的同时减少患者所接受的辐射剂量和碘注射量。     

超低管电流三维自适应迭代剂量降低重建CT猪结肠成像质量与辐射剂量

目的 探讨超低管电流三维自适应迭代剂量降低(AIDR3D)重建CT猪结肠成像的图像质量与辐射剂量。方法 制作10段猪结肠息肉模型,每段猪结肠黏膜设有30枚直径1~15 mm的结节样模拟息肉。对所有模型均采用640层CT机进行扫描,管电压120 kVp,电流剂量分别为10、20、30、40、50 mAs。并获得滤波反投影(FBP)和AIDR3D重建图像,不同管电流及重建方法组合10组数据:A组(10 mA,FBP)、B组(10 mAs,AIDR3D)、C组(20 mAs,FBP)、D组(20 mAs,AIDR3D)、E组(30 mAs,FBP)、F组(30 mAs,AIDR3D)、G组(40 mAs,FBP)、H组(40 mAs,AIDR3D)、I组(50 mAs,FBP)、J组(50 mAs,AIDR3D)。测算图像的噪声、SNR及CNR作为定量指标,并对图像质量进行主观定性评分。以有效辐射剂量为指标比较各组图像的辐射剂量。结果 相同管电流条件下,AIDR3D图像的噪声低于FBP图像,SNC及CNR均高于FBP图像(P均<0.05)。D组与I组图像的噪声(P=0.052)、SNR(P=0.129)及CNR(P=0.053)差异均无统计学意义。B组图像的噪声(P=0.002)高于I组,SNR及CNR均低于I组(P均<0.001)。相同管电流条件下,AIDR3D图像的质量评分高于FBP图像(P均<0.05)。D组与I组的图像质量评分差异无统计学意义(P=0.121)。B组的图像质量评分低于I组(P<0.001)。 与I组(50 mAs,FBP)比较,D组(20 mAs,AIDR3D)的有效辐射剂量降低了59.90%,差异有统计学意义(P<0.05)。结论 超低管电流(20 mAs)扫描结合AIDR3D重建的猪结肠CT图像质量可媲美常规低管电流(50 mAs)扫描结合FBP重建的图像质量,并有效减低辐射剂量。     

80 kVp扫描联合基于原始数据的迭代重建技术在儿童副鼻窦CT检查中的应用

目的 探讨Flash双源CT低管电压80 kVp扫描联合基于原始数据的迭代重建(SAFIRE)技术在儿童副鼻窦CT检查中的价值.方法 疑鼻窦炎行CT扫描患儿60例,A组30例采用100 kVp扫描,FBP重建;B组30例采用80 kVp扫描,SAFIRE重建,强度选择3级;其余条件不变.比较两组的有效剂量及图像质量的客观指标(CT值、图像噪声、SNR、CNR)、主观评分、诊断效能等.结果 A、B两组有效剂量、图像噪声、SNR、CNR差异均有统计学意义(P均 <0.05).两组图像的主观评分差异无统计学意义(P >0.05).两组诊断结果与临床诊断结果差异均无统计学意义(P均 >0.05).结论 在儿童副鼻窦扫描中采用Flash双源CT 80 kVp扫描联合SAFIRE重建技术,在显著降低辐射剂量的同时,还可保证图像质量及诊断效能,值得临床推广.     

模拟婴幼儿头颅70 kV CT扫描的图像质量和辐射剂量

目的 探讨模拟婴幼儿头颅70 kV CT扫描条件下的图像质量和辐射剂量。方法 选用CPT500模体,分别于70 kV及120 kV、150~500 mAs条件下进行扫描,测量其低对比度模块中对比度为1.0%、直径为15 mm的圆柱体的CNR和CTDIvol值,分析两者的相关性。由2名经验丰富的放射科医师对图像的低对比可探测能力（LCD）进行评分。对70 kV、150~500 mAs测得的每组图像的CNR和LCD评分与婴幼儿头颅常规扫描条件（120 kV、200 mAs）图像的差异行统计学分析。结果 当管电压为70 kV及120 kV时,图像CNR与CTDIvol呈线性正相关性（r=0.96、0.94,P<0.001）;当管电流设置为150~400 mAs时,70 kV与常规扫描条件图像的CNR及LCD评分的差异均有统计学意义（P均<0.05）,但当管电流设置为450~500 mAs时,差异均无统计学意义（P均>0.05）。结论 70 kV、450~500 mAs扫描条件可得到与传统的120 kV、200 mAs CT扫描相似的图像质量,前者辐射剂量明显降低,适用于婴幼儿头颅CT扫描。     

双源CT低管电压、低对比剂剂量及低流速注射头颈CTA研究

目的:探讨低管电压、低对比剂剂量、低流速注射扫描方案行头颈CTA可行性。方法:随机抽取2019年1月—2020年6月在我院进行头颈部CTA检查的受检者120例,随机分为A组60例,管电压100 kVp、对比剂剂量0.8mL/kg、注射流速4.5mL/s;B组60例,管电压80 kVp、对比剂剂量0.6 mL/kg、注射流速3.5 mL/s。两组均用对比剂碘海醇(350 mgI/mL)。比较两组头颈部血管内CT值、噪声(SD)、CNR、SNR、图像质量评分、CTDIvol、DLP,评价其图像质量及辐射剂量。结果:B组图像SNR、CNR较A组略低,两组不具有统计学差异(P>0.05);B组辐射剂量较A组明显降低,CTDIvol、DLP分别降低约49.4%、52.6%,B组碘摄入量较A组明显降低,降低约27.8%,两组CTDIvol、DLP、碘摄入量差异具有统计学意义(P<0.05)。结论:低管电压、低对比剂剂量及低流速注射在头颈部CTA检查中是可行的,图像质量能完全满足临床诊断需要,而且辐射剂量、碘摄入量明显降低。     

低管电压联合原始数据迭代重建技术在眼眶CT扫描中的应用

目的 探讨第二代双源CT低管电压(100 kVp)扫描联合基于原始数据迭代重建(SAFIRE)在眼眶扫描中的应用价值。方法 对100例疑似眼眶病变患者行CT扫描, 分为100 kVp扫描(A)组50例, SAFIRE重建, 选择强度3级, 120 kVp扫描(B)组50例, 滤波反投影(FBP)重建;比较两组的辐射剂量及图像的平均CT值、图像噪声、SNR、CNR、图像质量主观评分、诊断效能等。结果 A、B两组辐射剂量比较差异有统计学意义(t=3.59, P=0.01), A组较B组有效辐射剂量降低约33.78%;与B组相比, A组图像噪声降低21.52%;SNR提高22.88%;CNR提高28.88%;且差异均有统计学意义(P均<0.05)。两组图像的主观评分比较差异无统计学意义(t=0.34, P=0.88)。A、B两组CT诊断效能与临床诊断比较差异均无统计学意义(χ ²=0.08、0.10, P=0.99、0.99)。结论 采用第二代双源CT低管电压(100 kVp)联合SAFIRE重建技术行眼眶扫描, 能保证图像质量, 并可降低辐射剂量。     

Determination of creatine kinase isoenzyme MB activity in serum using immunological inhibition of creatine kinase M subunit activity. Activity kinetics and diagnostic significance in myocardial infarction.

This is a new method for the determination of creatine kinase isoenzyme MB activity in serum. The method uses direct activity measurement of creatine kinase B subunit activity after blocking of CK-M subunit activity by inhibiting antibodies. The test takes no longer than 15 min. The method yields an intra-serial C.V. of 2.0-12.9%, and a C.V. from day to day of 5.5%. The detection limit is 3.4 U/l creatine kinase MB. In the 95 cases with proven myocardial infarction several types of creatine kinase MB activity kinetics could be determined. The percentage of creatine kinase MB of peak CK-total is 6-25%, with a mean of 11.1%. The amount of creatine kinase MB with respect to total CK activity after reinfarction is higher than the amount after initial infarction.     

Dissociable correlates of two classes of retrieval processing in prefrontal cortex

Although substantial evidence suggests that the prefrontal cortex (PFC) implements processes that are critical for accurate episodic memory judgments, the specific roles of different PFC subregions remain unclear. Here, we used event-related functional magnetic resonance imaging to distinguish between prefrontal activity related to operations that (1) influence processing of retrieval cues based on current task demands, or (2) are involved in monitoring the outputs of retrieval. Fourteen participants studied auditory words spoken by a male or female speaker and completed memory tests in which the stimuli were unstudied foil words and studied words spoken by either the same speaker at study, or the alternate speaker. On "general" test trials, participants were to determine whether each word was studied, regardless of the voice of the speaker, whereas on "specific" test trials, participants were to additionally distinguish between studied words that were spoken in the same voice or a different voice at study. Thus, on specific test trials, participants were explicitly required to attend to voice information in order to evaluate each test item. Anterior (right BA 10), dorsolateral prefrontal (right BA 46), and inferior frontal (bilateral BA 47/12) regions were more active during specific than during general trials. Activation in anterior and dorsolateral PFC was enhanced during specific test trials even in response to unstudied items, suggesting that activation in these regions was related to the differential processing of retrieval cues in the two tasks. In contrast, differences between specific and general test trials in inferior frontal regions (bilateral BA 47/12) were seen only for studied items, suggesting a role for these regions in post-retrieval monitoring processes. Results from this study are consistent with the idea that different PFC subregions implement distinct, but complementary processes that collectively support accurate episodic memory judgments.     

俯卧位通气对高海拔地区肺复张治疗无效急性呼吸窘迫综合征患者氧合的影响

目的 探讨俯卧位通气对高海拔地区肺复张术(RM)治疗无效急性呼吸窘迫综合征(ARDS)患者的治疗作用.方法 从海拔2260m的地区医院筛选RM治疗无效的41例ARDS患者[平均氧合指数( PaO2/FiO2)较RM前升高＜20％视为RM无效],依不同病因分为肺内源性ARDS组(ARDSp组)和肺外源性ARDS组(ARDSexp组),每组再按信封法随机分为俯卧位组和仰卧位组,即ARDSp俯卧位组(11例)、ARDSp仰卧位组(9例)、ARDSexp俯卧位组(10例)、ARDSexp仰卧位组(11例).在通气前及通气1、2、3、4h监测动脉血氧分压( PaO2)、PaO2/FiO2、静态顺应性(Cst)、气道阻力(Raw)的变化.结果 通气lh时,ARDSexp俯卧位组PaO2/FiO2( mm Hg,l mm Hg=0.133 kPa)即较通气前显著升高(157.4±40.6比129.3±48.7,P＜0.05),并随通气时间延长呈持续增高趋势,4h达峰值(219.1 ±41.1);且ARDSexp俯卧位组通气3h内PaO2/FiO2较其他3组显著增高,另3组间则差异无统计学意义.ARDSp俯卧位组、ARDSexp俯卧位组通气4h时PaO2/FiO2均较相应仰卧位组显著增高(208.8±39.7比127.4±47.1,219.1±41.1比124.9±50.8,均P＜0.05).4组通气前后Cst无显著改变,各组间差异也无统计学意义.ARDSp俯卧位组通气4h时Raw(cmH2O·L-1·s-1)较通气前显著降低(6.8±1.7比10.7±1.8,P＜0.05),且明显低于其他3组;其他3组各时间点Raw组内及组间比较差异均无统计学意义.结论 俯卧位通气作为ARDS机械通气重要策略之一,可以改善RM无效高原ARDS患者的氧合,为抢救患者赢得宝贵的时间.     

Digital imaging among medical facilities

The Department of Veterans Affairs (VA) in the USA operates a network of 172 medical centres which all utilize a hospital information system (HIS) which has been developed and is currently maintained by the VA. During the past several years, an image management and communication module has been developed, installed and clinically utilized at the Washington DC and Maryland VA Medical Centres. This image management and communication system, referred to as the decentralized hospital computer program (DHCP) imaging system, is fully integrated with a commercial picture archiving and communication system (PACS). The system is utilized to capture, archive, and display all images generated within the hospital including radiology, nuclear medicine, pathology, endoscopy, bronchoscopy, and dermatology, intraoperative photographs, ECG data, and a limited number of paper documents. The ultimate goal of the project is to have all patient text and image data available at any clinical workstation to any authorized user anywhere within the network of medical centres. Clinical requirements for an imaging workstation include ease of use, rapid and reliable access to the complete set of patient information, and images which are of acceptable quality to meet the requirements of the user and the subspecialty. Patient confidentiality and data security must be safeguarded at all times. Integration of the images with the remainder of the patient's database was found to be critical to the success of the project. The experience at the Washington and Maryland facilities suggests that an imaging system that is successfully integrated with a hospital information system can provide substantial clinical and economic benefits both within and among medical centres. Clinical acceptance and utilization of the system has been excellent, particularly in diagnostic radiology where DHCP Imaging has been interfaced to a commercial PAC system. Based upon this initial experience, the VA has begun to deploy the system throughout its large network of medical centres.     

Myocardial elastography at both high temporal and spatial resolution for the detection of infarcts

Myocardial elastography is a novel method for noninvasively assessing regional myocardial function, with the advantages of high spatial and temporal resolution and high signal-to-noise ratio (SNR). In this paper, in-vivo experiments were performed in anesthetized normal and infarcted mice (one day after left anterior descending coronary artery [LAD] ligation) using a high-resolution (30 MHz) ultrasound system (Vevo 770, VisualSonics Inc., Toronto, ON, Canada). Radiofrequency (RF) signals of the left ventricle (LV) in longitudinal (long-axis) view and the associated electrocardiogram (ECG) were simultaneously acquired. Using a retrospective ECG gating technique, 2-D full field-of-view RF frames were acquired at an extremely high frame rate (8 kHz) that resulted in high-quality incremental displacement and strain estimation of the myocardium. The incremental results were further accumulated to obtain the cumulative displacements and strains. Two-dimensional and M-mode displacement images and strain images (elastograms), as well as displacement and strain profiles as a function of time, were compared between normal and infarcted mice. Incremental results clearly depicted cardiac events including LV contraction, LV relaxation and isovolumetric phases in both normal and infarcted mice, and also evidently indicated reduced motion and deformation in the infarcted myocardium. The elastograms indicated that the infarcted regions underwent thinning during systole rather than thickening, as in the normal case. The cumulative elastograms were found to have higher elastographic SNR (SNR(e)) than the incremental elastograms (e.g., 10.6 vs. 4.7 in a normal myocardium, and 6.0 vs. 2.4 in an infarcted myocardium). Finally, preliminary statistical results from nine normal (m = 9) and seven infarcted (n = 7) mice indicated the capability of the cumulative strain in differentiating infracted from normal myocardia. In conclusion, myocardial elastography could provide regional strain information at simultaneously high temporal (>/=0.125 ms) and spatial ( approximately 55 microm) resolution as well as high precision ( approximately 0.05 microm displacement). This technique was thus capable of accurately characterizing normal myocardial function throughout an entire cardiac cycle, at the same high resolution, and detecting and localizing myocardial infarction in vivo.     

Clinical Pharmacokinetics of Morphine

Morphine, the most widely used mu-opioid analgesic for acute and chronic pain, is the standard against which new analgesics are measured. A thorough understanding of the pharmacokinetics of morphine is required in order to safely and effectively use this analgesic in a wide variety of patients with different levels of organ function. A MEDLINE search was conducted to identify literature published between 1966 and January 2002 relevant to the pharmacokinetics of morphine. These publications were reviewed and the literature summarized regarding unique and clinically important elements of morphine disposition relative to its parenteral administration (including intravenous, intramuscular, subcutaneous, epidural and intrathecal administration), absorption profile (immediate release, controlled release, and sublingual/buccal, and rectal administration), distribution, and its metabolism/ excretion. Special populations, including infants, elderly, and those with renal/liver failure, have a unique morphine pharmacokinetic profile that must be taken into account in order to maximize analgesic efficacy and reduce the risk of adverse events.