瞬间反应式二次谐波显像评价正常犬肝脏超声学造影的实验研究

目的：评价瞬间反应二次谐波显像（Ｔｒａｎｓｉｅｎｔ ｒｅｓｐｏｎｓｅ ｓｅｃｏｎｄ ｈａｒｍｏｎｅｃ ｉｍａｇｉｎｇ,ＴＲＳＨＩ）对正常肝脏声学造影的增强效果及动态变化规律,并与常规连续二次谐波显像进行对比分析。方法：６只健康杂种犬 经外周静脉注射氟碳声学造影剂,分别用常规二次谐波显像和瞬间反应式二次谐波显像扫描肝脏。造影效果评价使用视觉评分和视频密度分析。结果：常规二次谐波显像有４次Ｉ级增强、４     

脑肿瘤的氢—磁共振波谱研究

目的 :分析脑肿瘤的氢 -磁共振波谱 (1H -MRS)改变 ,评价1H -MRS在脑肿瘤诊断、鉴别诊断、病理分级、预后估计等方面的价值。方法 :观察了 2 4例脑肿瘤的1H -MRS改变 ,其中胶质瘤 9例 ,脑膜瘤 6例 ,听神经瘤 2例 ,脑转移瘤 1例 ,颅咽管瘤 1例 ,斜坡脊索瘤 1例 ,垂体瘤 4例 ,同时选择 2 0名健康成人作为对照组。对1H-MRS所测得的N -乙酰天门冬氨酸 (NAA :2 0× 10 6)、肌酸 (Cr:3 0× 10 6)、胆碱 (Cho :3 2× 10 6)进行比较、分析。以积分面积表示 ,代表各化合物的相对浓度。结果 :胶质瘤NAA/Cho下降 ,与对照组有显著性差异 ,随着恶性度的上升 ,NAA/Cho下降更显著 ;6例脑膜瘤中 4例没有检测到NAA ,Cho/Cr较正常组明显升高 ;转移瘤检测到特征性的脂肪波 (Lip :1 4～ 1 5× 10 6)。结论 :1H -MRS可无创地分析脑肿瘤的代谢状况 ,对脑肿瘤的诊断、鉴别诊断、病理分极均有很大的价值。     

磁共振胰胆管成像的临床应用与进展

本文综述了磁共振胰胆管成像 (MRCP)的原理、技术及临床应用 ,讨论其与直接胆道造影比较的优、缺点 ,认为MRCP在很多情况下已可取代传统的诊断性内窥镜逆行胰胆管造影术 (ERCP)或经皮肝胆管造影术(PTC)的作用 ,并推测未来MRCP还将应用于胰胆管病变的介入治疗。     

THE VALUE OF 99mTc-MIBI MYOCARDIAL PERFUSION SPECT IMAGING IN DETECTING CORONARY ARTERY DISEASE IN PATIENTS WITH VALVULAR DISEASE BEFORE OPERATION

Objective. The aim of this study was to detect coronary artery disease using ^99mTc-MIBI myocardial perfusion imaging in patients with valvular disease. Methods. Thirty patients with valvular disease confirmed by echocardiography underwent ^99mTc-MIBI myocardial perfusion imaging using multiSPECT lh after stress test (exercise, dipyridamole or dobutamine test) and were performed coronary angiography within 1 month before valvular operation. Results. For 29 out of the 30 patients, the results of ^99mTc-MIBI myocardial perfusion imaging were similar with those of coronary angiography, the concordance rate was 96.7 % and the negative predictabili-ty was 100%. Conclusion. ^99mTc-MIBI myocardial perfusion imaging is a reliable non-invasive method for detecting coronary artery disease in patients with valvular disease and so as to draw up suitable operation programs for them.     

彩色多普勒血流显像对小孔室间隔缺损的诊断价值

目的　评价彩色多普勒血流显像 (CDFI)对小孔室间隔缺损 (VSD)的诊断价值。方法　对经CDFI诊断的 43例小孔VSD患者与手术治疗结果进行对照分析。结果　CDFI诊断阳性预测值为 95 % ,误、漏诊各 1例 ;整体定位阳性预测值为 88% ;40例彩色穿隔血流束宽测值与手术结果建立的回归方程式为Y =0 5 47+0 616X ,r =0 815 ,P <0 0 0 1;术前估测肺动脉收缩压 (PASP)为 ( 4 76± 1 93 )kPa。结论　CDFI诊断小孔VSD具有很高的特异性和准确性 ,并可估测患者术前的PASP。     

A whole-slide imaging based workflow reduces the reading time of pathologists

Even though entirely digitized microscopic tissue sections (whole slide images, WSIs) are increasingly being used in histopathology diagnostics, little data is still available on the effect of this technique on pathologists' reading time. This study aimed to compare the time required to perform the microscopic assessment by pathologists between a conventional workflow (an optical microscope) and digitized WSIs. WSI was used in primary diagnostics at the Laboratory for Pathology Eastern Netherlands for several years (LabPON, Hengelo, The Netherlands). Cases were read either in a traditional workflow, with the pathologist recording the time required for diagnostics and reporting, or entirely digitally. Reading times were extracted from image management system log files, and the digitized workflow was fully integrated into the laboratory information system. The digital workflow saved time in the majority of case categories, with prostate biopsies saving the most (68% time gain). Taking into account case distribution, the digital workflow produced an average gain of 12.3%. Using WSI instead of conventional microscopy significantly reduces pathologists' reading times. Pathologists must work in a fully integrated environment to fully reap the benefits of a digital workflow.     

Actions of 4-chloro-3-ethyl phenol on internal Ca2+ stores in vascular smooth muscle and endothelial cells

1. Recently, 4-chloro-3-ethyl phenol (CEP) has been shown to cause the release of internally stored Ca²⁺, apparently through ryanodine-sensitive Ca²⁺ channels, in fractionated skeletal muscle terminal cisternae and in a variety of non-excitable cell types. Its action on smooth muscle is unknown. In this study, we characterized the actions of CEP on vascular contraction in endothelium-denuded dog mesenteric artery. We also determined its ability to release Ca²⁺, by use of Ca²⁺ imaging techniques, on dog isolated mesenteric artery smooth muscle cells and on bovine cultured pulmonary artery endothelial cells.
2. After phenylephrine-(PE, 10 μM) sensitive Ca²⁺ stores were depleted by maximal PE stimulation in Ca²⁺-free medium, the action of CEP on refilling of the emptied PE stores was tested, by first pre-incubating the endothelium-denuded artery in CEP for 15 min before Ca²⁺ was restored for a 30 min refilling period. At the end of this period, Ca²⁺ and CEP were removed, and the arterial ring was tested again with PE to assess the degree of refilling of the internal Ca²⁺ store.
3. In a concentration-dependent manner (30, 100 and 300 μM), CEP significantly reduced the size of the post-refilling PE contraction (49.4, 28.9 and 5.7% of control, respectively) in Ca²⁺-free media. This suggests that Ca²⁺ levels are reduced in the internal stores by CEP treatment. CEP alone did not cause any contraction either in Ca²⁺-containing or Ca²⁺-free Krebs solution.
4. Restoring Ca²⁺ in the presence of PE caused a large contraction, which reflects PE-induced influx of extracellular Ca²⁺. The contraction of tissues pretreated with 300 μM CEP was significantly less compared with controls. However, tissues pretreated with 30 and 100 μM CEP were unaffected. Washout of CEP over 30 min produced complete recovery of responses to PE in Ca²⁺-free and Ca²⁺-containing medium suggesting a rapid reversal of CEP effects.
5. Concentration-response curves were constructed for PE, 5-hydroxytryptamine (5-HT) and K⁺ in the absence of and after 30 min pre-incubation with 30, 100 and 300 μM CEP. In all cases, CEP caused a concentration-dependent depression of the maximum response to PE (84.8, 43.4 and 11.6% of control), 5-HT (65.4, 25.7 and 6.9% of control) and K⁺ (77.6, 41.1 and 10.8% of control).
6. Some arterial rings were pre-incubated with ryanodine (30 μM) for 30 min before the construction of PE concentration-response curves. In Ca²⁺-free Krebs solution, ryanodine alone did not cause any contraction. However, 58% (11 out of 19) of the tissues tested with ryanodine developed contraction (6.9±1.2% of 100 mM K⁺ contraction, n=11) in the presence of external Ca²⁺. EC₅₀ values for PE in ryanodine-treated tissues (1.7±0.25 μM, n=16) were not significantly different from controls (2.5±0.41 μM, n=22). Maximum contractions to PE (118.5±4.4% of 100 mM K⁺ contraction, n=16) were also unaffected by ryanodine when compared to controls (129±4.2%, n=23).
7. When fura-2 loaded smooth muscle cells (n=13) and endothelial cells (n=27) were imaged for Ca²⁺ distribution, it was observed that 100 and 300 μM CEP in Ca²⁺-free medium caused Ca²⁺ release in both cell types. Smooth muscle cells showed a small decrease in cell length. Addition of EGTA (5 mM) reversed the effect of CEP on intracellular Ca²⁺ to control values.
8. These data show, for the first time in vascular smooth muscle and endothelial cells, that CEP releases Ca²⁺ more rapidly than ryanodine. Unlike ryanodine, CEP caused no basal contraction but depressed contractions to PE, 5-HT and K⁺. The lack of basal contraction may result from altered responsiveness of the contractile system to intracellular Ca²⁺ elevation.

     

Deciduous enamel defects in low-birth-weight children: correlated X-ray microtomographic and backscattered electron imaging study of hypoplasia and hypomineralization

Enamel does not remodel, and disturbances occurring during development may remain in the tooth as a permanent record of the upset. Mineralization in prenatal and postnatal deciduous enamel was studied in the shed deciduous incisors of low-birth-weight (LBW: < 2kg) children. The specific objective was to gain further insight into the mechanism of formation of developmental defects of enamel. Sections at a resolution of 22–40 m were reconstructed using X-ray microtomography (CT) giving absolute measurements of linear absorption coefficient for AgK radiation. Detail to ca. 1 m resolution was obtained using automated, digital backscattered electron (BSE) imaging of PMMA-embedded material. Matching the histograms of BSE and CT images made possible the calibration of the mean atomic number-dependent signal in the BSE images. The comparison of abnormal, affected enamel regions and post-recovery, normal, unaffected regions could be made in the same teeth, since these zones were easily recognized from the distribution of hypoplasia and hypomineralization. The CT values, converted to calculated mineral densities, ranged from 2.3 g cm^-3 to 2.6 g cm^-3 in LBW hypoplastic, and between 2.65 and 2.78 g cm^-3 in control primary enamel and post-defect, post-natal LBW enamel. Hypoplasia with or without minimal hypomineralization indicated recovery of the ameloblasts in the maturation phase. Disturbance during late matrix formation and early maturation resulted in hypoplasia and hypomineralization.     

Determination of left ventricular volume by two-dimensional echocardiography: comparison with magnetic resonance imaging

Left ventricular volume was determined in 12 healthy volunteersusing a newly developed two-dimensional echocardio-graphic delineationmethod. The results were compared with those of magnetic resonanceimaging, which served as the method of reference. Left ventricularend-diastolic volume was 123 ± 12 ml, echocardiographicallydefined, and 121 ± 12 ml calculated with magnetic resonanceimaging. End-systolic volume was 41 ± 7 ml on echocardiographyand 37±6 ml on magnetic resonance imaging. Left ventricularejection fraction was 67 ± 4%, echocardiographicallydefined, and 70 ± 5%, calculated with magnetic resonanceimaging. There was no statistical difference for any of themeasured parameters. Interstudy and inter-observer variabilitywas minimal. In conclusion, in healthy volunteers left ventricularvolume was accurately defined, using this newly developed two-dimensionalechocardiographic delineation method. During endocardial delineationa dynamic display is continuously available on a second window,allowing precise visual edge-detection. Moreover, correctionscan be made easily and quickly. These two advantages enhancethe accuracy of the method, even in cases of poor echogenicity.     

What might be the impact on neurology of the analysis of brain metabolism by in vivo magnetic resonance spectroscopy?

In vivo nuclear magnetic resonance spectroscopy (MRS) of the human brain is a recently developed technique which allows to assay noninvasively in vivo key molecules of brain metabolism. After a review of the origin of the signals detected by phosphorus and proton MRS of human brain, the impact of MRS on clinical neurology is examined. MRS of the brain does not purport to be a metabolic biopsy, but unique applications for brain MRS are (1) quantitating the oxidative state of the brain and defining neuronal death, (2) assessing and mapping neuron damage, (3) evaluating membrane alterations, and (4) characterizing encephalopathies. In the near future brain MRS will be performed routinely after conventional MRI, as a valuable metabolic (and functional) complement to the anatomical evaluation of cerebral pathologies, particularly the toxic, metabolic and infectious encephalopathies.