Morphological imaging and CT histogram analysis to differentiate pancreatic neuroendocrine tumor grade 3 from neuroendocrine carcinoma

PurposeTo compare morphological imaging features and CT texture histogram parameters between grade 3 pancreatic neuroendocrine tumors (G3-NET) and neuroendocrine carcinomas (NEC).Materials and methodsPatients with pathologically proven G3-NET and NEC, according to the 2017 World Health Organization classification who had CT and MRI examinations between 2006-2017 were retrospectively included. CT and MRI examinations were reviewed by two radiologists in consensus and analyzed with respect to tumor size, enhancement patterns, hemorrhagic content, liver metastases and lymphadenopathies. Texture histogram analysis of tumors was performed on arterial and portal phase CT images. images. Morphological imaging features and CT texture histogram parameters of G3-NETs and NECs were compared.ResultsThirty-seven patients (21 men, 16 women; mean age, 56 ± 13 [SD] years [range: 28-82 years]) with 37 tumors (mean diameter, 60 ± 46 [SD] mm) were included (CT available for all, MRI for 16/37, 43%). Twenty-three patients (23/37; 62%) had NEC and 14 patients (14/37; 38%) had G3-NET. NECs were larger than G3-NETs (mean, 70 ± 51 [SD] mm [range: 18 - 196 mm] vs. 42 ± 24 [SD] mm [range: 8 - 94 mm], respectively; P = 0.039), with more tumor necrosis (75% vs. 33%, respectively; P = 0.030) and lower attenuation on precontrast (30 ± 4 [SD] HU [range: 25-39 HU] vs. 37 ± 6 [SD] [range: 25-45 HU], respectively; P = 0.002) and on portal venous phase CT images (75 ± 18 [SD] HU [range: 43 - 108 HU] vs. 92 ± 19 [SD] HU [range: 46 - 117 HU], respectively; P = 0.014). Hemorrhagic content on MRI was only observed in NEC (P = 0.007). The mean ADC value was lower in NEC ([1.1 ± 0.1 (SD)] × 10⁻³ mm²/s [range: (0.91 - 1.3) × 10⁻³ mm²/s] vs. [1.4 ± 0.2 (SD)] × 10⁻³ mm²/s [range: (1.1 - 1.6) × 10⁻³ mm²/s]; P = 0.005). CT histogram analysis showed that NEC were more heterogeneous on portal venous phase images (Entropy-0: 4.7 ± 0.2 [SD] [range: 4.2-5.1] vs. 4.5 ± 0.4 [SD] [range: 3.7-4.9]; P = 0.023).ConclusionPancreatic NECs are larger, more frequently hypoattenuating and more heterogeneous with hemorrhagic content than G3-NET on CT and MRI.     

磁共振扩散加权成像在肝癌介入治疗前后应用的初步研究

目的探讨肝癌经导管动脉化疗栓塞术(TACE)前后不同b值下瘤区组织的平均表观扩散系数(ADC)的变化及其意义。方法对17例临床及影像学诊断为肝癌并行介入治疗的患者,术前及术后7天行常规平扫和磁共振扩散加权成像,比较不同b值下瘤区组织的平均ADC值的变化。结果在b值为50和100s/mm2时术前术后比较无统计学意义。在b值为300、500和700s/mm2时,术前术后的平均ADC值变化有显著性差异。当b值大于300s/mm2时,随着b值的升高平均ADC值逐渐升高,术后瘤区组织的平均ADC值较术前升高,在b值为1000和1300s/mm2时图像质量太差无法测量。结论对肝癌TACE术后疗效进行评价时,b值最好选择300～700s/mm2之间。DWI通过瘤区DWI图像、eADC图像、ADC图像信号的变化和平均ADC值可以反映TACE术后瘤组织内的微观及超微结构的变化,平均ADC值可以为其早期疗效的判断提供量化标准。     

Comparing diffusion-weighted and T2-weighted MR imaging for the quantification of infarct size in a neonatal rat hypoxic–ischemic model at 24 h post-injury

PURPOSE: In a neonatal rat model of hypoxic-ischemic (HI) brain injury, using T2-weighted imaging (T2WI) and diffusion-weighted imaging (DWI), we aim to determine the best MRI method of lesion quantification that reflects infarct size. MATERIALS AND METHODS: Twenty 7-day-old rats underwent MRI 24h after HI brain injury was induced. Lesion size relative to whole brain was measured using T2WI and apparent diffusion coefficient (ADC) maps, applying thresholds of 60%, 70% and 80% contralateral control hemisphere mean ADC, and at day 10 post-HI on pathology with TTC staining. Multiple linear regression analysis was used to study the relationships between lesion size at MRI and pathology. RESULTS: Lesion size measurement using all MRI methods significantly correlated with infarct size at pathology; using T2WI, r=0.808 (p<0.001), using 80% ADC, 70% ADC and 60% ADC thresholds, r=0.888 (p<0.001), 0.761, (p<0.001) and 0.569 (p=0.014), respectively. Eighty percent ADC threshold was found to be the only significant independent predictor of final infarct volume (adjusted R(2)=0.775). CONCLUSION: At 24h post-HI, lesion size on DWI, using 80% ADC threshold is the best predictor of final infarct volume. Although T2WI performed less well, it has the advantage of superior spatial resolution and is technically less demanding. These are important considerations for experiments which utilize MRI as a surrogate method for lesion quantification in the neonatal rat HI model.     

White matter damage precedes that in gray matter despite similar magnetic resonance imaging changes following cerebral hypoxia-ischemia in neonatal rats

We hypothesized that the cerebral injury produced by hypoxia-ischemia (HI) in neonatal rats would differ in white compared with gray matter as detected histologically or with magnetic resonance (MR) imaging methods. Maps of T₂ and the apparent diffusion coefficient (ADC) of water were acquired in 1-week-old rats at times prior to cerebral HI (right carotid artery occlusion plus 1.5 h of hypoxia), within the last 5–10 min of HI, and 1 h or 24 h after HI. Near the end of HI, ADC decreased and T₂ increased in both cortical gray and subcortical white matter within the cingulum of the HI hemisphere. One hour after HI, ADC partially recovered, but T₂ remained increased and then increased further by 24 h post-HI. In contrast to the similar MR responses in white and gray matter, histological evidence for irreversible cell damage occurred in white matter earlier than in gray matter within the HI hemisphere. At 1 h post-HI, rarefied or disrupted nerve fibers and an increase in TUNEL-positive cells were observed within white matter in the cingulum, whereas neurons within the cortical gray matter appeared normal. By 24 h post-HI, damage was apparent in both white and gray matter. Thus, MR imaging detected acute tissue edema following cerebral HI in both gray and white matter but did not distinguish between the early irreversible tissue injury detected histologically in white but not gray matter in this rather severe model of neonatal encephalopathy.     

Interpretation of gas-blood ratio inP O 2polarography

Summary The differences inP _{O 2}readings between gas and blood were studied with a Clark-type electrode in the range of 38.5 to 713 mm HgP _{O 2}.The tonometered blood samples were taken in two different ways. The results showed that the gas-blood ratior _b(equilibrating gasP _{O 2}reading/equilibrated bloodP _{O 2}reading) depended not only on the sampling method but also on theP _{O 2}range: it varied from 1.005 to 1.032 for aP _{O 2}of 96.5 mm Hg, and from 1.040 to 1.081 for aP _{O 2}of 713 mm Hg according to the sampling procedure.A theoretical analysis demonstrated that the variation ofr _bwith the bloodP _{O 2}can be attributed to the influence of the degree of oxygen saturation of the hemoglobin on theP _{O 2}gradient existing in the blood diffusion boundary layer adhering to the electrode membrane.This work was supported by grants from the High Authority of the European Coal and Steel Community and from the Fonds de la Recherche Scientifique Médicale, Belgium.     

Epidemiologic Correlation and Drug Resistance Analysis of Pathogenic Bacteria in Different Open Limb Injury External Conditions

ObjectiveTo study the epidemiological correlation and drug resistance of external factors of infection caused by open injury of limbs to pathogens.MethodsThis experiment is a retrospective study. We took the geographical location and climate of Nanchang, Jiangxi Province, China as the background, analyzed 2017 strains of pathogens from 1589 patients with limb trauma infection in a University Affiliated Hospital from 2012 to 2017. Patients were divided into three groups according to the type of incision: I, In‐hospital infection of clean limb incision, II, In‐hospital infection with open injury, III, Community infection with open injury of the limb. Groups II and Groups III were divided into six subgroups according to the causes of trauma, including: accidents from non‐motor vehicles, machinery, cutting/piercing, pedestrian injuries, struck by/against, pedal cycles, and other injuries. We found eight common pathogens of orthopedic infection, which were mainly divided into Gram‐positive bacteria (G+, mainly including Staphylococcus) and Gram‐negative bacteria (G‐, mainly Enterobacteriaceae). The relationship between main pathogens and damage mechanism, apparent temperature and relative humidity was discussed in this study. SPSS v22.0 was used for statistical analysis of the data. Friedman''s two‐way ANOVA was used to analyze the difference between the injury mechanism and incidence of pathogenic bacteria. Linear regression was used to determine the trend between the incidence of major pathogens and seasonal temperature and humidity. The level of significance was set as P < 0.05.ResultsThere was no significant difference in the distribution of pathogens between Groups II and Groups III (P>0.05). The drug resistance of Groups III was significantly higher than that of Groups II and Groups I. G+ bacteria were resistant to cephalosporin, ceftriaxone and other cephalosporins and erythromycin and other macrolides. They were sensitive to vancomycin and linezolid. G‐ were resistant to the first‐ and the second‐generation cephalosporins, including cefotetan and cefazolin, and ampicillin and other penicillins, while they were sensitive to third‐generation cephalosporins, such as ceftazidime, as well as to levofloxacin and other quinolones, meropenem, and other beta‐lactamases. The correlation between the injury mechanism and infection of pathogenic bacteria was not significant. The monthly average apparent temperature and relative humidity were correlated with the infection rate of pathogenic bacteria.ConclusionIn open injury of extremities, apparent temperature and relative humidity is an important risk factor for infection by pathogenic bacteria and the drug resistance of pathogenic bacteria in out‐of‐hospital infection was lower than that of hospital infection.     

磁共振扩散加权成像和ADC值在前列腺癌诊断中的应用价值

目的探讨磁共振扩散加权成像（DWI）及表观扩散系数（ADC）在前列腺癌诊断中的应用价值。资料与方法回顾分析经组织病理学证实的前列腺癌49例患者资料,DWI采用单次激发平面回波序列（EPI）。感兴趣区（ROI）包括前列腺癌、前列腺良性增生（BPH）和正常前列腺周围带,并计算相应的ADC值。结果49例前列腺癌患者血清前列腺特异抗原（PSA）平均为49.1ng/ml。肿瘤病灶ROI的ADC值在X、Y和Z轴方向分别有41、9和13例获得;前列腺良性增生分别在3个方向为39、11和13例;正常前列腺周围带为31、9和10例。前列腺癌在X、Y和Z轴方向平均ADC值分别为2.282×10^-3mm^2/s、2.293×10^-3mm^2/s和3.017×10^-3mm^2/s;BPH各个方向平均ADC值分别为2.559×10^-3mm^2/s、2.812×10^-3mm^2/s和3.585×10^-3mm^2/s;正常前列腺外周区组织3个方向的平均ADC值分别为2.892×10^-3mm^2/s、3.303×10^-3mm^2/s和4.112×10^-3mm^2/s。前列腺癌在X轴方向的ADC值明显低于相同方向前列腺增生和正常周围带的ADC值（P〈0.005）。结论DWI和ADC值在前列腺癌的诊断中应用方便、易行,ADC值是区别前列腺癌组织和非肿瘤组织的可靠指标。     

多b值磁共振扩散加权成像在前列腺良、恶性结节中的对比研究

目的：通过对前列腺结节多b值的定量分析研究,探讨评价DWI对前列腺良、恶性结节的临床应用价值。方法回顾性分析经手术及病理证实的36例前列腺结节的常规MRI及DWI征象,分别测量在多b值条件下良、恶性结节的表观扩散系数（ADC）,并讨论不同b值的应用价值。结果本组36例患者中,良性结节25例,恶性结节11例。采用b值（200、400、600、800、1000s/mm2）时良性组与恶性组之间ADC值的差异均有统计学意义（P<0.05）。结论前列腺良性结节的ADC值高于恶性结节,在多b值的扩散加权成像中,尤其以b值取800 s/mm2时,鉴别良、恶性结节的效能最高,有助于前列腺结节性质的判断和鉴别,对其术前诊断分期、术后治疗方案的设计制定,都有着十分重要的指导意义。     

豆腐果苷理化常数的测定

目的:测定豆腐果苷油水分配系数、溶解度和pKa值等理化常数。方法:参照《中国药典》(2005版)相关方法测定豆腐果苷在不同水溶液及不同有机溶剂中的近似溶解度;采用电位滴定法测定豆腐果苷的pKa值;采用摇瓶法测定豆腐果苷在不同的pH下的表观油水分配系数。结果:豆腐果苷属微溶药物,且在乙醚、乙酸乙酯和氯仿等有机溶剂中几乎不溶;豆腐果苷显弱酸性,pKa值为5.65±0.13。豆腐果苷的表观油水分配系数随pH值的升高而降低,且符合logP=-0.0211pH-1.0174的函数关系。在生理条件pH7.4时,豆腐果苷表观油水分配系数为0.067。在(25±0.1)℃条件下,豆腐果苷真实油水分配系数为0.0834。结论:豆腐果苷是一种脂溶性较差的弱酸性微溶药物。     

脑梗死患者磁共振弥散加权成像ADC值演变的临床研究

目的 通过观察脑梗死患者磁共振弥散加权成像ADC值的变化,探讨脑梗死不同时期ADC值相对应的脑水肿的变化规律.方法 选取本院2013年1月至2014年8月收治的脑梗死并行磁共振DWI检查的病例269例,采集脑梗死后超早期(≤6h)、急性期(6～24h)、坏死期(24～48h)、软化期(48h～3w)ADC值变化,并将脑梗死患者按前后循环、灰白质观察及分析各组ADC值的差别.结果 脑梗死急性期DWI图像均为高信号,而ADC图为低信号.超早期病灶侧ADC均值为(0.524±0.080),急性期为(0.401±0.081),坏死期为(0.369±0.084)[较急性期下降(P＜0.001)],软化期为(0.524±0.100)[较坏死期上升(P＜0.001)],ADC值由高到低再逐渐升高,呈“U”型变化.白质病灶侧ADC均值较灰质降低[(0.432±0.103) vs.(0.455±0.126),P＜0.05];前循环病灶侧ADC均值较后循环降低[(0.431±0.117)vs.(0.479±0.095),P＜0.01].结论 ADC值可用于预判脑梗死细胞水肿的类型,有助于指导临床治疗.