重型颅脑损伤持续颅内压及脑灌注压监护与预后关系

作者对５０例重型颅脑损伤患者（ＧＣＳ３－８分），及５０例伤情与诊断和手术方式基本相似的另一组患者进行颅内压（ＩＣＰ）与脑灌注压（ＣＣＰ）连续监测对比研究。结果表明，监护组除８例ＩＣＰ压力＜２．００ｋＰａ，ＣＰＰ＞９．３３ｋＰａ外，余４２例均有不同程度ＩＣＰ增高与ＣＰＰ降低。这些患者分别为创伤性颅内血肿、广泛性脑挫裂伤、继发性脑水肿或脑肿胀等，均采取积极的手术及综合治疗。死亡率为１４％。非监护组治疗方法与监护组相同，预后较差且并发症多，死亡率为２８％。作者认为，对重型颅脑损伤患者施行连续ＩＣＰ、ＣＰＰ监护，是降低并发症和死亡率，提高疗效的有力措施，具有重要的临床应用价值。     

离体灌流鼠心胞浆游离钙——fura—2测定

本实验建立了一种浮动基点式ｆｕｒａ－２测定离体灌流心脏细胞内游离钙浓度的新模型，本模型中游动基点式测定地克服目前ｆｕｒａ－２技术中受细胞内某些物质产生的自身荧光变化干扰的缺点，实现了自动消除细胞自身荧光变化对实验结果的影响，并在此基础上将广泛用于测定游离状态的细胞内游离钙的ｔｕｒａ－２技术推广到离体灌流心脏，实现了在更接近心肌生理状态的条件下测定其胞浆游离钙。     

逆行灌注心脏不停跳心肌保护的实验研究

目的：探讨逆行灌注心脏不停跳心肌保护的效果。方法：中国大白兔32只随机分为4组，每组8只，A组（对照组），B组（心脏不停跳组，血温34℃），C组（温血心脏麻痹液组，血温34℃），D组（冷血心脏麻痹液组，血温4℃）。采用离体兔心左室做功模型，经冠状静脉窦逆行灌注稀释血液或血停搏液60min。比较观察心功能、冠脉排出液心肌酶谱、心肌组织乳酸、心肌细胞内游离钙浓度、心肌细胞膜ATP酶活性、心肌细胞膜脂质过氧化产物丙二醛含量的变化。结果：B组心功能恢复、心肌细胞膜ATP酶活性显著优于C组和D组，C组优于D组；B组心肌酶漏出、乳酸生成量、心肌细胞内游离钙浓度、心肌细胞膜丙二醛（MDA）含量低于C组和D组，C组低于D组。结论：常温氧合血逆灌心脏不停跳良好的心肌保护效果与其减轻自由基损伤，较好地保持细胞内外Ca^2 平衡，减轻细胞内钙超载，保护细胞膜酶功能有关。     

经皮局部隔离肝脏灌注化疗合并血液灌流方法学实验研究

目的　探讨经皮局部隔离肝脏灌注化疗的方法及可行性。方法　 12只实验用犬 ,对照组 4只 ,进行常规经肝动脉灌注化疗 ;实验组 8只 ,利用介入放射学方法进行经皮局部隔离肝脏灌注化疗结合血液灌流。化疗药物选用阿霉素 ,分别检测肝静脉及外周血液中的血药浓度。结果　实验组介入操作全部成功 ,1例死于血液灌流的血路管漏气 ,平均操作时间 ( 132 .3± 15 .3)min。血药浓度测定显示 ,对照组肝静脉血和外周静脉血浓度峰值分别为 ( 370 9.676± 385 .72 3)ng/ml、( 15 76.14 0± 2 2 6.933)ng/ml;实验组为( 465 3.42 0± 430 .2 0 4)ng/ml、( 433.612± 40 .5 0 1)ng/ml。统计学处理 ,两组相差非常显著。结论　经皮局部隔离肝脏灌注化疗结合血液灌流是一种可行的技术 ,具有简单、创伤小、可保护正常肝脏、便于重复治疗的优点。与常规经肝动脉灌注化疗相比 ,不仅可以增加局部血药浓度 ,更可以降低外周的血药浓度 ,降低毒副作用     

肝腺瘤的影像学诊断

目的探讨影像学(US、CT、MRI及DSA)诊断肝腺瘤的价值。方法回顾性分析经手术、病理证实的11例肝腺瘤的影像学表现,其中11例行US和CT检查(有1例行CT灌注成像,CTP),5例行MRI扫描,4例行DSA检查,并与手术病理所见对照。结果11例肝腺瘤均为单发肿块,无肝硬化背景,直径2.0～10.0cm。影像学表现:US检查,10例呈稍低或不均匀稍强回声,边界清晰,6例见低回声晕,彩色多普勒显示肿块内有较丰富的血流;CT检查,10例为稍低或等密度,8/10例动脉期全瘤明显强化,门脉期轻度强化,延迟期呈等密度,1例平扫和延迟期呈等密度,动脉期中度强化,门脉期轻度强化,误诊为血管瘤。1/11例CT灌注成像(CTP)检查,肝动脉灌注量(HAP)=1.08ml/(min.ml),门静脉灌注量(PVP)=0.19ml/(min.ml),肝动脉灌注指数(HPI)=0.85,各参数值与肝癌均有明显不同;MRI检查,5例肝腺瘤均能显示完整包膜,T1WI上2例稍高于肝脏信号,1例呈等信号,2例为稍低信号,T2WI上5例均表现为以稍高信号为主的混杂信号,脂肪抑制像(STIR)1例呈略低信号,4例信号与T2WI相似,行增强扫描的4例病灶动脉期显著强化,门脉期强化减退,平衡期呈等信号。DSA检查,3/4例病灶见粗细不均的异常血管影,实质期可见肿瘤染色表现。结论肝腺瘤的US和DSA表现均缺乏特异性,CT、MRI则具有一定的特点。CTP对肝腺瘤可能具有诊断和鉴别诊断价值。     

动脉自旋标记法磁共振成像在颈动脉狭窄性脑缺血疾病中的初步应用

目的:对比研究颈动脉严重狭窄患者动脉自旋标记法(ASL)和动态磁化率效应对比剂增强(DSC)磁共振脑灌注成像表现,探讨ASL的临床运用价值。材料和方法:健康自愿者12例,行DSC和ASL,计算左侧大脑中动脉供血区与右侧相应区域相对脑血流量(rCBF)比值并进行比较。病例组为单侧颈内动脉狭窄程度≥70％患者32例,计算DSC和ASL所得的患侧与健侧大脑中动脉供血区rCBF比值并进行比较。结果:12例健康自愿者所测的DSC和ASL的rCBF比值分别为1．0012±0．1030和1．0015±0．1611,无统计学差异。32例患者中,15例患者灌注异常,DSC与ASL的rCBF比值相比无显著性差异(P=0．072)。结论:ASL序列能快速无创的提供脑灌注情况,可作为初步了解颈动脉狭窄性脑缺血疾病脑灌注情况的常规检查方法。     

Detection of moderate and severe coronary artery stenosis with technetium-99m tetrofosmin myocardial single-photon emission tomography

The aim of this study was to determine the diagnostic accuracy of technetium-99m tetrofosmin myocardial imaging for the localization of coronary artery stenoses of different degrees of severity. Stress-rest single-photon emission tomography (SPET) was performed on separate days in 80 patients (64 males, 16 females; mean age 61 years; 43 patients with previous myocardial infarction; 18 patients with pharmacological stress), within 6 months of coronary angiography. Scintigraphic images were blindly and independently evaluated by three observers. Coronary stenosis was defined as a >50% narrowing in luminal diameter; severe stenosis was defined as a proximal stenosis of >75% or a peripheral stenosis of >90%. Coronary angiography revealed normal coronary arteries or insignificant coronary stenosis in 13 patients and significant coronary stenoses in 67 patients. The sensitivity and specificity of ^99mTc-tetrofosmin SPET in respect of severely stenosed vessels were, respectively, 80% and 65% for the left anterior descending artery (LAD), 100% and 46% for the right coronary artery (RCA) and 58 and 78% for the left circumflex artery (LCx) territories. Considering all the significantly stenosed vessels, a significant decrease in sensitivity was observed for LAD territories (to 59%, P=0.05), and a nonsignificant decrease for RCA (88%) and LCx (47%) territories while specificity values remained essentially unchanged. No significant changes in sensitivity or specificity were observed when regions with previous myocardial infarction were excluded. In conclusion, the sensitivity of ^99mTc-tetrofosmin SPET for the localization of individual stenosed vessels is only moderate when all significant stenoses are considered, but the ability of this technique to predict the location of severe coronary artery stenoses seems satisfactory, with the exception of the low specificity in respect of RCA territories. Received 26 April and in revised form 7 June 1997     

Transfer of clonidine and dexmedetomidine across the isolated perfused human placenta

Background: The placental transfer of the a₂ receptor agonist clonidine, earlier used as an adjuvant in obstetric epidural analgesia, was compared with the transfer of the newer and more %-selective agonist dexmedetomidine.
Methods: Term placentas were obtained immediately after delivery with maternal consent and a 2-hour recycling perfusion of a single placental cotyledon was performed. Disappearance from the maternal circulation, accumulation in placental tissue and appearance in the fetal circulation of clonidine or dexmedetomidine with the reference compound antipyrine were followed in 4 experiments for both drugs.
Results: At 2 hours the percent dexmedetomidine found in the fetal circulation was 12.5 (SD 5.1)%, while 48.1 (SD 20.3)% was found in the perfused placental cotyledon. A higher mean clonidine than dexmedetomidine concentration was achieved in the fetal circulation (1.90 vs. 0.56 nmol/l, P <0.05). At 2 hours the percent clonidine found in the fetal circulation was 22.1 (SD 2.4)% ( P <0.05), while 11.3 (SD 3.3)% ( P <0.05) was re tained in the perfused placental cotyledon. The transfer indexes, describing maternal-to-fetal transfer of dexmedetomidine and clonidine normalized with the transfer of antipyrine, were 0.88 (SD 0.07) and 1.04 (SD 0.08) respectively ( P <0.05).
Conclusions: Dexmedetomidine disappeared faster than clonidine from the maternal circulation, while even less dexmedetomidine was transported into the fetal circulation. This was due to its greater placental tissue retention, the basis for which probably is the higher lipophilicity of dexmedetomidine.     

Perfusion imaging by a flow-sensitive alternating inversion recovery (Fair) technique: Application to functional brain imaging

Perfusion is a crucial physiological parameter for tissue function. To obtain perfusion-weighted images and consequently to measure cerebral blood flow (CBF), a newly developed flow-sensitive alternating inversion recovery (FAIR) technique was used. Dependency of FAIR signal on inversion times (TI) was examined; signal is predominantly located in large vessels at short TI, whereas it is diffused into gray matter areas at longer TI. CBF of gray matter areas in the human brain is 71 ± 15 SD ml/100 g/min (n = 6). In fMRI studies, micro- and macrovessel inflow contributions can be obtained by adjusting TIs. Signal changes in large vessel areas including the scalp were seen during finger opposition at a TI of 0.4 s; however, these were not observed at a longer TI of 1.4 s. To compare with commonly used BOLD and slice selective inversion recovery techniques, FAIR and BOLD images were acquired at the same time during unilateral finger opposition. Generally, activation sites determined by three techniques are consistent. However, activation of some areas can be detected only by FAIR, not by BOLD, suggesting that the oxygen consumption increase couples with the CBF change completely. Relative and absolute CBF changes in the contralateral motor cortex are 53 ± 17% SD (n = 9) and 27 ± 11 SD ml/100 g/min (n = 9), respectively.     

Scintigraphic evaluation of hepatic blood flow after intrahepatic portosystemic shunt (TIPS)

In patients with liver cirrhosis a transjugularly placed intrahepatic portocaval shunt (TIPS) is a non-surgical portosystemic device which aims to reduce portal venons pressure. In comparison with Doppler sonography, we evaluated in 28 patients the diagnostic impact of liver perfusion scintigraphy (with technetium-99m diethylene triamine penta-acetic acid) in the assessment of changes in the hepatic blood flow after TIPS shunting. The arterial and portal contributions to hepatic flow were calculated from the areas under the biphasic timeactivity curve. In the course of TIPS shunting, patency is threatened by reocclusion. Angiography is the gold standard for TIPS shunt reassessment. However, there is a need for a less invasive diagnostic procedure, such as scintigraphy or Doppler sonography, for the early detection of shunt insufficiency. Scintigraphy demonstrated that prior to TIPS shunting the portal venons contribution to hepatic perfusion was reduced to 29.2%, this reduction being due to portal hypertension. After TIPS placement a significant increase in portal venous perfusion was observed (38.2%;P<0.02). TIPS shunt occlusion was identified in patients by a significant reduction in the scintigraphically measured portal venons contribution to hepatic blood flow. Hepatic perfusion scintigraphy appears to be a valuable method to determine the immediate effect of TIPS on hepatic blood flow. Post-TIPS follow-up studies of hepatic haemodynamics by liver perfusion scintigraphy appear able to contribute to the detection of TIPS shunt occlusion before the clinical consequences of this complication have become apparent.