MSCT灌注成像对积水肾脏单肾功能评价的实验研究

目的采用多层螺旋CT（MSCT）灌注成像技术测定肾积水模型的各项灌注参数,探讨其对积水肾脏单肾功能的诊断价值。材料与方法8周龄以上成年健康雄性实验大白兔20只,制作右侧输尿管部分梗阻模型．分别在梗阻前、梗阻后4周行MSCT灌注扫描、单光子正电子发射计算机体层成像（SPECT）检查及彩色多普勒超声显像（CDFI）检测,取积水肾脏标本,光镜下观察病理学变化。结果梗阻后4周MSCT灌注成像可见肾盂扩张,肾皮质明显变薄,皮、髓质血流量（BF）、血容量（BV）较梗阻前有明显下降（P〈0．01）,对比剂平均通过时间（MTT）变化无明显差异,肾皮质表面通透性（PS）有轻度下降趋势,但与梗阻前相比,无显著性差异,而肾髓质PS则较梗阻前有显著性降低（P〈0．01）。CDFI显示梗阻后肾动脉、肾内动脉收缩期峰值速度（PSV）均降低（P〈0．05）,舒张末速度（EDV）显著低于梗阻前（P〈0．01）,阻力指数（RI）显著高于梗阻前（P〈0．01）。SPECT测定结果显示梗阻后右肾肾小球滤过率（GFR）均显著低于梗阻前（P〈0．001）,达峰时间（Tb）显著延长（P〈0．001）,半排时间（T（1/2））显著延长,无测定意义。结论肾积水模型在梗阻前、后皮、髓质MSCT灌注参数的变化以BF、BV下降最明显。此结果与CDFI测定的PSV、EDV及RI所反映的肾血流动力学变化相一致。MSCT灌注技术的出现无疑为l临床评价单肾功能开拓了思路,随着MSCT灌注软件的不断发展,其在单肾功能评价方面一定会显示出巨大的临床应用价值。     

Influence of Pulse Duration on X-ray Emission during Industrial Ultrafast Laser Processing

Soft X-ray emissions during the processing of industrial materials with ultrafast lasers are of major interest, especially against the background of legal regulations. Potentially hazardous soft X-rays, with photon energies of >5 keV, originate from the fraction of hot electrons in plasma, the temperature of which depends on laser irradiance. The interaction of a laser with the plasma intensifies with growing plasma expansion during the laser pulse, and the fraction of hot electrons is therefore enhanced with increasing pulse duration. Hence, pulse duration is one of the dominant laser parameters that determines the soft X-ray emission. An existing analytical model, in which the fraction of hot electrons was treated as a constant, was therefore extended to include the influence of the duration of laser pulses on the fraction of hot electrons in the generated plasma. This extended model was validated with measurements of H (0.07) dose rates as a function of the pulse duration for a constant irradiance of about 3.5 × 10¹⁴ W/cm², a laser wavelength of 800 nm, and a pulse repetition rate of 1 kHz, as well as for varying irradiance at the laser wavelength of 1030 nm and pulse repetition rates of 50 kHz and 200 kHz. The experimental data clearly verified the predictions of the model and confirmed that significantly decreased dose rates are generated with a decreasing pulse duration when the irradiance is kept constant.     

双能量CT定量参数预测实性肺腺癌气道播散

目的 观察双能量CT(DECT)定量参数术前预测实性肺腺癌气道播散(STAS)状态的价值。方法 回顾性分析52例经手术病理确诊实性肺腺癌患者的DECT及病理学资料,评估其STAS状态(阳性或阴性);对比STAS阳性、阴性实性肺腺癌CT表现(最大径、周围不透明影、空气支气管征、胸膜凹陷征)及DECT定量参数的差异。针对差异有统计学意义的DECT定量参数绘制受试者工作特征(ROC)曲线,计算曲线下面积(AUC),评估DECT定量参数单独及联合预测实性肺腺癌STAS的效能,并以二元logistic回归分析筛选实性肺腺癌STAS的独立预测因子。结果 52例中,25例STAS阳性,27例STAS阴性,其间病灶CT表现差异均无统计学意义(P均>0.05),DECT定量参数中的动脉期碘浓度(IC_A)、动脉期标准化碘浓度(NIC_A)及静脉期碘浓度(IC_V)差异均有统计学意义(P均<0.05)。IC_A、NIC_A及IC_V预测实性肺腺癌STAS的AUC为0.82、0...     

基于蒙特卡罗模拟的小动物质子CT最优射束能量

目的 观察基于蒙特卡罗模拟的小动物质子CT(PCT)的最优射束能量。方法 采用蒙特卡罗模拟建立PCT系统,分别以不同能量质子束对体模1、2进行扫描,并以滤波反投影法重建图像,观察其中不同材料质子的相对阻止本领(RSP)值、重建误差、空间分辨率、信号噪声比(SNR)及对比噪声比(CNR),评估图像质量,筛选最优质子射束能量。结果 重建图像中,特氟龙、聚丙烯及骨骼等效材料的RSP的相对误差均随质子能量增高而先降后升,于质子能量为130 MeV时最小,分别为0.76%、0.08%及0.05%。体模1内4种插件的SNR和CNR均随质子能量增高而降低。重建图基本无法分辨体模2内直径0.2 mm铝插件,质子能量较低时可分辨直径0.4 mm铝插件;不同质子能量下均可分辨直径0.8 mm铝插件,且空间分辨率随质子能量增高而提升,质子能量大于130 MeV后变化趋缓。结论 以蒙特卡罗模拟的小动物PCT平台的最优成像质子射束能量为130 MeV。     

1例脾脏癌肉瘤CT表现

<正>患者女,56岁,间断左上腹隐痛1年余;既往无特殊病史。查体：左上腹轻压痛,无反跳痛,脾脏肋缘下5 cm。肿瘤标志物：CA-125 48.334 U/ml, 甲胎蛋白793.152 ng/ml。腹部超声：左上腹脾胃间隙内11.4 cm×14.7 cm不均匀回声占位,外形尚规则,部分边界不清,CDFI见彩色血流信号。腹部CT:平扫脾脏前部9.7 cm×12.5 cm×14.0 cm近球形混杂密度肿块,边界不清,内见不规则低密度区,     

能谱CT术前诊断胃腺癌周围神经侵犯

目的 观察能谱CT术前诊断胃腺癌周围神经侵犯(PNI)的价值。方法 对270例拟行手术治疗的胃腺癌患者于术前1周内行能谱CT扫描,测量增强动脉期、静脉期和延迟期病灶碘浓度(IC)和标准化IC(nIC);据术后病理报告将患者分为PNI组和无PNI组,对比组间病灶IC和nIC差异,以多因素logistic回归分析筛选PNI独立危险因素,采用受试者工作特征(ROC)曲线评估IC参数诊断PNI的效能。结果 270例中,术后病理证实123例PNI(PNI组)、147例无PNI(无PNI组);组间肿瘤厚度、Borrmann分型、(术前)临床T分期(cT)、CT报告淋巴结状态、病理T分期(pT)及病理N分期(pN)差异均有统计学意义(P均<0.05)。PNI组病灶静脉期IC(ICVP)、延迟期IC(ICDP)及静脉期nIC(nICVP)、延迟期nIC(nICDP)均高于无PNI组(P均<0.001)。logistic回归分析显示,cT分期和nICDP是PNI的独立危险因素;ROC曲线示cT分期联合nICDP诊断PNI的曲线下面积(0.832)高于单一cT分期及IC参数(P均<0.0...     

1例遗传性平滑肌瘤病和肾细胞癌综合征PET/CT表现

<正>患者女,29岁,1周前体检发现左肾占位;1年前因“子宫肌瘤”接受“腹腔镜下子宫肌瘤剔除术”;其母曾因“子宫肌瘤”接受“子宫全切术”。查体及实验室检查均未见明显异常。¹⁸FFDG PET/CT：左肾及腹膜后见异常高代谢灶,子宫代谢增高(图1A);左肾上极2.1cm×2.1cm肿物(图1B),腹膜后多发肿大淋巴结、彼此融合(图1C),子宫多发结节(图1D);考虑左肾恶性病变伴腹膜后多发淋巴结转移,子宫多发肌瘤。行全麻下腹腔镜下左肾切除+腹膜后肿物切除术,术中见左肾肿物最大径约3cm,质硬;腹膜后球形肿物最大径约5cm,与腹主动脉关系密切。     

Ⅰ型自身免疫性胰腺炎的CT及MRI表现

目的 探讨I型自身免疫性胰腺炎(I-AIP)的CT及MRI表现.资料与方法 回顾性分析16例经病理证实的I-AIP的临床资料、CT及MRI表现.结果 16例I-AIP中,14例IgG4水平升高;胰腺弥漫型受累9例,呈"腊肠状"改变,其中6例可见"胶囊征";局灶型受累7例.CT平扫呈均匀等或低密度,MRI平扫T1WI呈低...     

Structural Basis of the Avian Influenza NS1 Protein Interactions with the Cell Polarity Regulator Scribble

Scribble is a highly conserved regulator of cell polarity, a process that enables the generation of asymmetry at the cellular and tissue level in higher organisms. Scribble acts in concert with Disc-large (Dlg) and Lethal-2-giant larvae (Lgl) to form the Scribble polarity complex, and its functional dysregulation is associated with poor prognosis during viral infections. Viruses have been shown to interfere with Scribble by targeting Scribble PDZ domains to subvert the network of interactions that enable normal control of cell polarity via Scribble, as well as the localisation of the Scribble module within the cell. The influenza A virus NS1 protein was shown to bind to human Scribble (SCRIB) via its C-terminal PDZ binding motif (PBM). It was reported that the PBM sequence ESEV is a virulence determinant for influenza A virus H5N1 whilst other sequences, such as ESKV, KSEV and RSKV, demonstrated no affinity towards Scribble. We now show, using isothermal titration calorimetry (ITC), that ESKV and KSEV bind to SCRIB PDZ domains and that ESEV unexpectedly displayed an affinity towards all four PDZs and not just a selected few. We then define the structural basis for the interactions of SCRIB PDZ1 domain with ESEV and ESKV PBM motifs, as well as SCRIB PDZ3 with the ESKV PBM motif. These findings will serve as a platform for understanding the role of Scribble PDZ domains and their interactions with different NS1 PBMs and the mechanisms that mediate cell polarity within the context of the pathogenesis of influenza A virus.     

螺旋CT在脊柱结核的诊断价值与鉴别诊断中的应用分析

目的 探讨提高脊柱结核的CT诊断价值与鉴别诊断.方法 对X线怀疑或已诊断脊柱结核的50例患者进行CT扫描,并分析CT影像表现.结果 49例显示椎体破坏,42例椎旁脓肿,2例病变侵及椎管,41例椎间盘破坏,7例椎体附件破坏.结论 脊柱结核在CT上有着典型的影像学表现,特别是对于估价骨质破坏程度和侵及椎管及椎旁软组织块影的范围更有价值.