T2-mapping成像评估腰部背伸肌群运动前后功能状态

目的 探讨T2-mapping评估健康志愿者运动前后腰部背伸肌群（多裂肌、最长肌、髂肋肌）的价值。方法 对50名健康志愿者运动前后行T2-mapping序列扫描,于L3、L4上缘层面测量运动前后多裂肌、最长肌、髂肋肌的横截面积（CSA）及T2值,比较运动前后及左右侧上述肌肉CSA、T2值的差异,并分析运动前后各肌肉的CSA差值与T2值差值的相关性。结果 L3、L4椎体上缘水平双侧多裂肌、最长肌、髂肋肌运动后CSA、T2值均大于运动前（P均<0.05）。L3椎体上缘水平左侧多裂肌的运动后CSA及运动前后CSA差值均大于右侧（P均<0.05）。运动前L3椎体上缘水平左右侧最长肌、髂肋肌及L4椎体上缘水平左右侧最长肌的T2值差异均有统计学意义（P均<0.05）。L3、L4椎体上缘水平双侧髂肋肌及L4椎体上缘水平双侧多裂肌运动前后CSA差值与T2值差值呈正相关（P均<0.05）。结论 T2-mapping可用于评估腰部背伸肌群运动前后功能变化。     

腰大肌及侧腹肌相关CT参数评价肝硬化肌少症

目的 观察腰大肌及侧腹肌相关CT参数评价肝硬化肌少症的价值。方法 采集210例临床诊断肝硬化患者腹部CT,获得L3水平骨骼肌总横截面积,计算相应骨骼肌指数（SMI）。根据SMI结果将患者分为肌少症组（n=105）与非肌少症组（n=105）,测量相同层面右侧腰大肌轴径及横径、右侧腹肌厚度,计算腰大肌轴径指数（APMI）、腰大肌横径指数（TPDI）及侧腹肌厚度指数（LWMI）;比较组间差异。以SMI结果为标准,绘制TPDI、APMI及LWMI鉴别肝硬化肌少症的受试者工作特征（ROC）曲线,计算曲线下面积（AUC）,并分析TPDI、APMI及LWMI与SMI的相关性及肌少症的影响因素。结果 组间体质量指数、胆固醇、NRS2002评分、APMI、TPDI和LWMI差异均有统计学意义（P均<0.05）。TPDI（r=0.71）、APMI（r=0.59）和LWMI（r=0.61）均与SMI呈正相关（P均<0.01）。APMI、TPDI及LWMI鉴别肝硬化肌少症的AUC分别为0.61、0.71及0.72（P均<0.05）。男性、三酰甘油为肌少症的危险因素,TPDI、LWMI为肌少症的保护因素（P均<0.05）。结论 腰大肌及侧腹肌相关CT参数可用于评估肝硬化肌少症,并有望成为临床评估肌少症的新方法。     

双能量CT虚拟去钙图诊断椎体骨髓水肿

目的 探讨双源CT双能量虚拟去钙（DE-VNCa）图在不同对比物质相对比值（RCMR）条件下对椎体骨髓水肿的临床诊断价值。方法 对37例脊柱外伤及腰背部疼痛患者行双源CT双能量扫描及MR检查,RCMR值分别取1.28、1.45、1.75、1.85,重建4组DE-VNCa图像。以MRI诊断为金标准,计算4组图像诊断椎体骨髓水肿的效能,获得最优RCMR值,并在此最优条件下测量并比较腰椎骨髓水肿区与正常椎体的CT值和脂肪含量,以ROC曲线评价CT值和脂肪含量诊断腰椎骨髓水肿的效能。结果 RCMR值取1.28、1.45、1.75、1.85时,诊断腰椎骨髓水肿的约登指数分别为0.02、0.35、0.82、0.73;RCMR为1.75时,DE-VNCa图诊断效能最高。以RCMR=1.75重建DE-VNCa图,腰椎骨髓水肿区与正常椎体的CT值和脂肪含量差异均有统计学意义（P均<0.01）。以CT值=10.25 HU和脂肪含量=24.50%为临界值,诊断腰椎骨髓水肿的AUC分别为0.95和0.91（P均<0.01）。结论 双源CT DE-VNCa图在RCMR为1.75时诊断椎体骨髓水肿的临床价值较高;CT值和脂肪含量有助于诊断腰椎骨髓水肿。     

超声诊断非酒精性脂肪肝与CT定量测量腹部脂肪分布的相关性

目的 观察健康人群超声诊断非酒精性脂肪肝（NAFL）与CT定量测量腹部脂肪分布的相关性。方法 分析1 285名体检者一般资料、血糖、生化指标和超声脂肪肝诊断结果以及CT定量测量腹部脂肪面积值，包括总脂肪（TF）、内脏脂肪（VF）和皮下脂肪（SF），观察超声诊断NAFL与CT定量测量值的关系。结果 最终诊断NAFL 504例。超声诊断NAFL与非脂肪肝在脐层面和L2/3层面VFA、SFA、TFA之间差异均有统计学意义（P均<0.05）。男性脐层面VFA、L2/3层面VFA及SFA越高，NAFL发生风险率越高；女性L2/3层面VFA及SFA越高，NAFL发生风险率越高。超声诊断NAFL与脐层面及L2/3层面脂肪面积均呈较好的正相关，且L2/3层面VFA、SFA及TFA均高于脐层面。结论 健康成人中NAFL与腹部脂肪含量相关；VF异常积累易致非肥胖人群罹患NAFL。     

儿童粒细胞肉瘤MRI表现及文献复习

目的 观察儿童粒细胞肉瘤（GS）的MRI表现。方法 回顾性分析经病理确诊的4例GS患儿的MRI资料,观察肿瘤的位置、大小、形态、信号特点、骨质破坏情况及强化特点。结果 4例GS,3例为多发病变,1例单发。1例病灶位于T3~T7椎体水平椎管内硬膜外及椎旁、双侧上颌窦及蝶窦窦壁、眶周;1例位于L1~L2椎体水平椎管内硬膜外及椎旁;1例位于T2~T4、T10~T11椎体水平椎管内硬膜外及椎旁;1例位于T11~T12、L4~S2椎体水平椎管内硬膜外及椎旁、左侧眼眶、蝶骨及右侧额窦窦壁;均在局部形成软组织肿块或经椎间孔达椎管外形成椎旁肿块。3例骨髓信号受到弥漫性抑制。所有病灶的T1WI信号均较周围正常肌肉稍高,脂肪抑制T2WI均呈稍高信号,增强扫描后均呈轻中度均匀强化。2例椎体骨质破坏,表现为T1WI明显低信号,脂肪抑制T2WI明显高信号,增强扫描后明显均匀强化。结论 儿童GS的MRI表现具有一定特征性,有助于本病诊断。     

对比水-脂分离成像技术与频率选择饱和法在头颈部增强MRI中的脂肪抑制效果

目的 对比分析水-脂分离技术（Dixon技术）与频率选择饱和法（FS）在头颈部增强MRI中的脂肪抑制效果。方法 对接受头颈部增强MR检查的49例患者行Dixon和FS脂肪抑制T1WI。由2名放射科医师评价其脂肪抑制效果,计算并比较2种图像间CNR和磁场中心层面（小脑、延髓）、偏离磁场中心层面（颞叶、咬肌、锁骨）的SNR。结果 49例患者的Dixon图像中,2名医师分别记录了14处和17处脂肪抑制效果不佳的区域,一致性好（Kappa=0.858,P<0.001）;FS图像中分别记录192处和175处脂肪抑制效果不佳区域,一致性好（Kappa=0.890,P<0.001）。在磁场中心层面,Dixon图像噪声小于FS图像（P<0.001）,小脑SNR、延髓SNR及CNR优于FS组（P均<0.05）。在偏离磁场中心层面,Dixon图像噪声小于FS图像（P=0.010）,咬肌SNR优于FS图像（P=0.010）,锁骨SNR小于FS图像（P<0.001）;2种图像颞叶SNR和CNR差异均无统计学意义（P均>0.05）。结论 对于头颈部增强MRI,应用Dixon技术较FS能获得更好的图像质量和脂肪抑制效果。     

定量CT测定人体腹部脂肪分布、肝脏脂肪含量与肥胖的相关性

目的 探讨人体腹部脂肪分布、肝脏脂肪含量与肥胖的相关性。方法 收集于我院接受定量CT （QCT）腰椎骨密度（BMD）检查的健康体检者123名,将受检者分为肥胖组与正常组,比较2组间L_2~3、L_3~4、L_4~5、L₅~S₁椎间隙水平层面的腹腔内脏脂肪面积（VAA）、肝脏脂肪含量百分比β值,分析肥胖组与正常组差异有统计学意义的椎间隙水平层面VAA值与年龄、BMI的相关性。结果 肥胖组L_4~5椎间隙水平层面VAA较正常组增大（P=0.005）,2组余椎间隙VAA比较差异无统计学意义（P均 > 0.05）;肥胖组肝脏脂肪含量百分比β值较正常组增高（P=0.001）;肥胖组L_4~5椎间隙水平层面VAA与年龄及BMI均呈正相关（r=0.485、0.389;P=0.012、0.049）。结论 QCT可评估肥胖者腹部脂肪的分布;L_4~5椎间隙水平层面VAA可预测肥胖风险;肝脏脂肪含量百分比β值在定量诊断肥胖者肝脏脂肪含量具有特异性。     

Modic Ⅱ型改变对经皮椎间孔镜术疗效的影响

目的 探讨Modic改变对经皮椎间孔镜术疗效的影响。方法 回顾性分析2018年1月－2019年12月在该科行经皮椎间孔镜下腰椎髓核切除术（PELD）的43例腰椎间盘突出症（LDH）患者,根据磁共振成像（MRI）示是否伴有Modic改变将其分为MC组与对照组,分析两组患者术中出血量、手术时间、术前、术后3 d、术后3和6个月的腰痛及腿痛视觉模拟评分（VAS）、日本骨科协会评分（JOA）及Oswestry功能障碍指数（ODI）。结果 两组患者术中出血量、手术时间、术前腰痛VAS评分、术前及术后腿痛VAS评分、术前ODI与JOA评分比较,差异均无统计学意义（P > 0.05）,但术后3 d、术后3和6个月腰痛VAS评分MC组高于对照组（P < 0.01）,术后3和6个月MC组JOA评分均低于对照组（P < 0.01）,术后3和6个月MC组ODI均高于对照组（P < 0.01）,同时与术前相比,两组患者6个月时腰痛VAS评分、腿痛VAS评分、JOA评分及ODI均有改善（P < 0.05）。结论 经皮椎间孔镜术对伴随Modic改变（Ⅱ型）的LDH患者具有良好的疗效,是一种可靠、安全的治疗手段,但Modic改变会影响术后腰痛的缓解,针对此类患者需综合考虑治疗方案。     

椎体成形术治疗单个椎体转移瘤骨水泥用量与骨水泥渗漏及疼痛缓解的关系

目的 分析经皮椎体成形术治疗椎体转移性肿瘤中骨水泥用量与骨水泥渗漏及疼痛缓解情况的关系,并探讨CT诊断术后骨水泥渗漏的价值。方法 分析接受经皮椎体成形术治疗的53例单个椎体转移性肿瘤患者的临床资料,比较有骨水泥渗漏和无骨水泥渗漏患者的骨水泥用量及疼痛缓解情况。结果 所有经皮椎体成形术均获得成功。术后CT检查较术后即刻的DSA检查更易发现骨水泥渗漏(P<0.05),发生渗漏患者的骨水泥使用量显著高于未发现渗漏的患者(P<0.05),但发生与未发生骨水泥渗漏患者之间的疼痛缓解情况差异无统计学意义(P>0.05)。结论 经皮椎体成形术治疗椎体转移性肿瘤术后的CT检查对发现骨水泥渗漏是必要的,在治疗过程中不能过于追求骨水泥的充填。     

能谱CT多参数鉴别诊断肾上腺乏脂性腺瘤与结节性增生

目的 观察能谱CT多参数鉴别诊断肾上腺乏脂性腺瘤（Lp-AA）与肾上腺结节性增生（ANH）的价值。方法 回顾性分析经手术病理证实的Lp-AA（n=24,Lp-AA组）和ANH（n=20,ANH组）患者的常规CT平扫和动、静脉期能谱CT增强图像,比较组间动、静脉期标准化40~140 keV（间隔10 keV）单能量CT值、各基物质对浓度、有效原子序数及能谱曲线差异。针对差异有统计学意义的参数,绘制其鉴别Lp-AA与ANH的受试者工作特征（ROC）曲线,分析其诊断效能。结果 组间动脉期标准化40~70 keV单能量CT值、碘-脂、脂-碘、钙-水、碘-水浓度、能谱曲线斜率差异均有统计学意义（P均<0.05）,标准化有效原子序数及80~140 keV单能量CT值差异均无统计学意义（P均>0.05）。组间静脉期标准化40~50 keV单能量CT值、脂-碘、羟基磷灰石-水、碘-水浓度及标准化有效原子序数差异均有统计学意义（P均<0.05）,其余参数差异均无统计学意义（P均>0.05）。上述参数鉴别Lp-AA与ANH的曲线下面积（AUC）为0.73~0.82,以碘-脂浓度的诊断效能最高,AUC为0.82。结论 能谱CT多参数对鉴别Lp-AA与ANH具有一定价值。     

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.