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。     

脊柱多发郎格汉斯细胞组织细胞增多症的CT、MRI征象分析

目的 探讨脊柱多发郎格汉斯细胞组织细胞增多症（LCH）的CT、MRI征象。方法 回顾性分析13例经病理证实的脊柱多发LCH患者的影像学检查资料,13例均接受CT检查（1例增强扫描）,其中12例接受MR检查（6例增强扫描）。结果 13例中,单中心病变8例,多中心病变5例。共34个病变脊椎,其中核心病变脊椎19个,邻近侵犯脊椎15个。18个（18/19,94.74%）核心病变脊椎存在不同形态、程度的压缩骨折。13例患者共34个病变脊椎CT均表现为溶骨性骨质破坏;19个核心病变脊椎中,18个（18/19,94.74%）骨皮质不完整、可见椎旁软组织肿块。MRI显示12例患者共33个病变脊椎,包括核心病变脊椎18个,邻近侵犯脊椎15个,T1WI均呈等、稍低或低信号,T2WI呈稍高或高信号,脂肪抑制序列呈高信号;17个（17/18,94.44%）核心病变脊椎有椎旁软组织肿块。结论 脊柱多发LCH的CT、MRI表现具有一定特征性,加深对本病影像表现的认识可提高诊断和鉴别水平,但确诊需依靠病理检查。     

椎管内血管脂肪瘤的MRI表现

目的:分析椎管内血管脂肪瘤的MRI影像特点。方法 :收集我院手术病理证实的椎管内血管脂肪瘤8例,对其术前MRI影像进行回顾性分析。结果:8例椎管内血管脂肪瘤中,术后证实6例位于胸腰段硬膜外,1例位于胸腰段脊髓内,1例位于腰骶段髓外硬膜下;MRI术前定位准确8例,定性准确5例,另外3例定性为良性肿瘤。硬膜外病灶呈梭形压迫硬膜,椎管狭窄,于蛛网膜下腔与肿瘤间显示受压线样硬膜影,部分椎管内外生长病灶呈哑铃型伴椎间孔扩大,周围骨质无破坏;脊髓内病灶呈椭圆形,两端脊髓呈杯口状改变;硬膜下病灶呈新月形于硬膜下生长,硬膜无受压改变,椎管明显狭窄。病灶在T1WI、T2WI上均以等高信号为主,T2WI压脂后7例病灶信号增高,仅1例脊髓内病灶压脂后信号明显降低;增强后4例表现为轻度强化,3例中度强化,1例明显强化,6例强化均匀,2例强化不均匀。结论:椎管内血管脂肪瘤多发生于硬膜外,少数发生于脊髓内及硬膜下,本研究中有1例患者病灶位于硬膜下。MRI能清楚显示血管脂肪瘤的大小、形态、信号特点及其与椎管邻近结构的关系,具有准确定位及定性诊断价值。     

椎管内硬膜外肿瘤MRI诊断与鉴别诊断

目的探讨椎管内硬膜外肿瘤MRI特点及其鉴别诊断。方法回顾分析15例经手术证实的椎管内硬膜外肿瘤MR表现。结果本组转移瘤4例,T1WI多表现为稍低信号,T2WI为不均匀高信号,增强扫描后均为不均匀强化;淋巴瘤2例,T1WI均为低信号,T2WI为等信号,增强扫描后均明显强化,有邻近椎体的骨质破坏。脂肪瘤8例,表现为T1WI、T2WI均呈高信号;血管瘤1例。结论椎管内硬膜外肿瘤种类繁多,但以恶性肿瘤最多,MRI对椎管内硬膜外肿瘤的定位定性诊断具有较高的准确性。     

硬膜外脊膜瘤的影像学表现

目的 观察扁平形硬膜外脊膜瘤的影像学表现。方法 回顾性分析8例经手术病理证实的扁平形硬膜外脊膜瘤的影像学表现表现,并进行文献复习。结果 7例硬膜外脊膜瘤位于颈椎管,1例位于胸椎管,累及2~4个椎体节段;8例病灶均呈扁平形、以增厚的硬膜为基底,伴硬膜外肿块形成;5例肿瘤经椎间孔向硬膜外延伸、相应水平椎间孔扩大;椎管均均匀变窄,1例伴脊髓水肿,1例伴脊髓变性。CT显示病灶呈等密度,6例硬膜可见条片状钙化。MRI显示病灶于轴位图像上均呈半环形,包绕脊髓,T1WI上呈等（n=5）或低（n=3）信号,T2WI上呈等（n=3）或低信号（n=5）;增强后呈中等（n=2）或明显（n=6）强化,其中7例强化均匀,1例不均匀。结论 扁平形硬膜外脊膜瘤好发于颈椎管,可累及多个椎体节段,以硬膜增厚、钙化并硬膜外肿块形成为其特征。     

脊柱累及硬膜外原始神经外胚层肿瘤的CT与MRI表现

目的：分析脊柱硬膜外原发性原始神经外胚层肿瘤（PNET）的CT及MRI表现特征。材料与方法：回顾性分析7例经病理证实的累及硬膜外的PNET的CT及MRI表现。结果：7例PNET,肿块信号强度不均匀,在T1WI上呈低信号4例、等信号3例,在T2WI上均呈高或稍高信号,增强扫描均可见不均匀强化,坏死囊变2例,6例累及椎体或/和附件,CT上表现为溶骨性骨质破坏。6例形成较大的椎旁软组织肿块,其中5例从扩大椎间孔向外蔓延,呈哑铃状。结论：脊柱硬膜外PNET的CT及MRI表现具有一定的特征性,病灶密度或信号不均匀,常累及椎骨及椎管,伴有椎间孔扩大,形成较椎管内肿物大的椎旁软组织肿块。     

椎管内髓外硬膜下毛细血管瘤临床及MRI特征

目的 探讨椎管内髓外硬膜下毛细血管瘤的临床及MRI特征。方法 回顾性分析5例经手术病理确诊的椎管内髓外硬膜下毛细血管瘤的临床资料及MRI表现。结果 临床表现:胸背痛伴双下肢麻木、无力4例,颈部疼痛伴双上肢疼痛1例。MRI示肿块均为单发,均位于椎管内硬脊膜下脊髓背侧,胸段4例,颈段1例;T1WI呈等(4例)或低信号(1例),T2WI呈高信号,增强后多均匀强化(4例);病灶周围可见含铁血黄素沉积(1例)、脊膜尾征(1例)及肿块头侧可见引流血管(1例)。结论 椎管内髓外硬膜下毛细血管瘤好发于中年人,位于脊髓背侧。MRI特征表现为肿块周围引流血管、含铁血黄素沉积、脊膜尾征、显著均匀强化。     

乳腺黏液癌的MRI征象特点

目的 分析乳腺黏液癌的MRI表现特征。方法 回顾性分析经手术病理证实的34例乳腺黏液癌的MRI表现,包括病变形态、最大径、T1WI及T2WI信号特征、肿块内部强化方式及增强曲线类型、DWI信号特征及ADC值。结果 34例乳腺黏液癌单纯型22例,混合型12例。MRI示21例为肿块型,6例为非肿块型,7例为多发结节型;T1W平扫22例呈低信号,10例呈等信号,2例呈混杂高信号;T2W脂肪抑制序列20例呈高信号,13例呈不均匀高信号,1例呈低信号,19例病灶内可见低信号纤维分隔;动态增强早期呈典型环形强化11例;时间-信号曲线呈流入型11例,平台型18例,流出型5例。结论 乳腺黏液癌的MRI表现有一定特点,MR检查有助于对该病的诊断。     

肝脏上皮样血管内皮瘤MRI征象

目的 观察肝脏上皮样血管内皮瘤（EHE）的MRI表现。方法 回顾性分析经病理证实的18例肝脏EHE患者的MRI资料,观察肿瘤分布、大小、形状、边界、信号强度、强化方式等,探讨其MRI特征,并测量病变及周围正常肝组织的ADC值。结果 18例EHE均为多发病灶,其中结节型10例,融合型8例。病变于平扫T1WI均呈低信号,16例T2WI呈"靶征"（边缘稍高信号伴中央更高信号）,2例呈混杂信号;DWI均呈高信号,病灶ADC值为（1.58±0.25）×10^-3 mm²/s,高于周围正常肝组织ADC值[（1.34±0.12）×10^-3 mm²/s,t=4.014,P=0.001]。增强扫描10例结节型中7例呈环形渐进性向心强化,其中3例见"双环征",3例呈持续环形强化;8例融合型中,7例呈云絮状渐进性强化,1例呈环形渐进性向心强化。16例病灶内见血管穿行,13例血管止于病灶边缘或病灶内,15例伴肝包膜回缩。结论 肝脏EHE的MRI表现具有一定特征性,有助于诊断和鉴别诊断。     

椎管内节细胞神经瘤MRI征象

目的 分析椎管内节细胞神经瘤的MRI征象,以提高术前诊断能力。方法 回顾性分析9例经手术病理证实、累及椎管的节细胞神经瘤MRI资料,观察肿瘤位置、形态、大小、信号和强化程度等。结果 共纳入9个病灶,其中位于颈椎4个,胸椎2个,腰骶椎3个;7个累及椎管内外,呈哑铃状,2个位于椎间孔区,呈结节状;9个病灶T2WI均呈均匀或不均匀高信号,1个病灶内见囊变坏死。8个接受增强扫描的病灶中,3个呈明显强化,5个呈轻中度强化,4个病灶内见条状强化。所有病灶均伴有受累椎间孔扩大,但骨质未见破坏。结论 椎管内节细胞神经瘤MRI表现具有一定特征性,有助于术前准确诊断。     

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.