Importance of b value in diffusion weighted imaging for the diagnosis of pancreatic cancer

AIM:To investigate the use of multi-b-value diffusionweighted imaging in diagnosing pancreatic cancer.METHODS:We retrospectively analyzed 33 cases of pancreatic cancer and 12 cases of benign pancreatic tumors at the Second Affiliated Hospital of Kunming Medical University from December 2008 to January2011.The demographic characteristics,clinical presentation,routine magnetic resonance imaging and diffusion weighted imaging(DWI)features with different b values were reviewed.Continuous data were expressed as mean±SD.Comparisons between pancreatic cancer and benign pancreatic tumors were performed using the Student’s t test.A probability of P<0.05 was considered statistically significant.RESULTS:Thirty-three patients with pancreatic cancer were identified.The mean age at diagnosis was 60±5.6 years.The male:female ratio was 21:12.Twenty cases were confirmed by surgical resection and 13 by biopsy of metastases.T1 weighted images demonstrated a pancreatic head mass in 16 patients,a pancreatic body mass in 10 cases,and a pancreatic tail mass with pancreatic atrophy in 7 cases.Eight patients had hepatic metastases,13 had invasion or envelopment of mesenteric vessels,4 had bone metastases,and 8had lymph node metastases.DWI demonstrated an irregular intense mass with unclear margins.Necrotic tissue demonstrated an uneven low signal.A b of 1100s/mm2was associated with a high intensity signal with poor anatomical delineation.A b of 700 s/mm2was associated with apparent diffusion coefficients(ADCs)that were useful in distinguishing benign and malignant pancreatic tumors(P<0.05).b values of 50,350,400,450 and 1100 s/mm2were associated with ADCs that did not differentiate the two tumors.CONCLUSION:Low b value images demonstrated superior anatomical details when compared to high b value images.Tumor tissue definition was high and contrast with the surrounding tissues was good.DWI was useful in diagnosing pancreatic cancer.

WB-DWI对于乳腺癌患者术后临床评价

目的:研究核磁共振全身弥散加权成像(WB-DWI)在乳腺癌患者术后随访评价中的应用价值。方法:选取2020年5月-2023年6月在我院接受手术治疗的乳腺癌患者200例为对象,均在本院接受乳腺癌全切术治疗,术后定期随访中分别进行WB-DWI检查,并以术后病理随访结果为金标准,计算WB-DWI检查对乳腺癌术后复发、远处转移、腋窝淋巴结转移的诊断价值。结果:WB-DWI对乳腺癌术后复发或远处转移的诊断准确率、灵敏度和特异度分别为97.00%、97.44%、96.72%;WB-DWI对术后腋窝淋巴结转移的诊断准确率、灵敏度和特异度分别为94.00%、90.53%、97.14%;转移性淋巴结的ADC值明显低于非转移性淋巴结的ADC值(P<0.05),且ADC值对腋窝淋巴结转移的最佳诊断阈值为0.895×10^(-3)mm^(2)/s,AUC值为0.795;不同骨组织转移灶的ADC值明显低于正常骨组织的ADC值(P<0.05),且ADC值对骨转移的最佳诊断阈值为0.983×10^(-3)mm^(2)/s,AUC值为0.834。结论:乳腺癌术后的临床评价中应用WB-DWI检查具有快速、无创、无需造影剂、安全、无辐射、可短期重复扫描等优点,能得到类似PET-CT图像,敏感度高,能早期检出转移灶和复发灶,为乳腺癌术后复发和转移的早期发现提供可靠的信息,值得推广应用。

Optimal b value of diffusion-weighted imaging on a 3.0T magnetic resonance scanner in Crohn's disease

AIM: To determine the optimal b value of diffusion-weighted imaging for detecting active inflammation in Crohn&#x02019;s disease.

Prognostic value of M30/M65 for outcome of hepatitis B virus-related acute-on-chronic liver failure

AIM: To determine the prognostic value of circulating indicators of cell death in acute-on-chronic liver failure (ACLF) patients with chronic hepatitis B virus (HBV) infection as the single etiology. METHODS: Full length and caspase cleaved cytokeratin 18 (detected as M65 and M30 antigens) represent circulating indicators of necrosis and apoptosis. M65 and M30 were identified by enzyme-linked immunosorbent assay in 169 subjects including healthy controls (n = 33), patients with chronic hepatitis B (CHB, n = 55) and patients with ACLF (n = 81). According to the 3-mo survival period, ACLF patients were defined as having spontaneous recovery (n = 33) and non-spontaneous recovery which included deceased patients and those who required liver transplantation (n = 48). RESULTS: Both biomarker levels significantly increased gradually as liver disease progressed (for M65: P < 0.001 for all; for M30: control vs CHB, P = 0.072; others: P < 0.001 for all). In contrast, the M30/M65 ratio was significantly higher in controls compared with CHB patients (P = 0.010) or ACLF patients (P < 0.001). In addition, the area under receiver operating characteristic curve (AUC) analysis demonstrated that both biomarkers had diagnostic value (AUC >= 0.80) in identifying ACLF from CHB patients. Interestingly, it is worth noting that the M30/M65 ratio was significantly different between spontaneous and non-spontaneous recovery in ACLF patients (P = 0.032). The prognostic value of the M30/M65 ratio was compared with the Model for End-Stage Liver Disease (MELD) and Child-Pugh scores at the 3-mo survival period, the AUC of the M30/M65 ratio was 0.66 with a sensitivity of 52.9% and the highest specificity of 92.6% (MELD:AUC = 0.71; sensitivity, 79.4%; specificity, 63.0%; Child-Pugh: AUC = 0.77; sensitivity, 61.8%; specificity, 88.9%). CONCLUSION: M65 and M30 are strongly associated with liver disease severity. The M30/M65 ratio may be a potential prognostic marker for spontaneous recovery in patients with HBV-related ACLF. (C) 2014 Baishideng Publishing Group Co., Limited. All rights reserved.

多b值DWI联合HR-T_(2)WI在直肠癌术前分期及环周切缘评估中的应用

目的 探讨多b值扩散加权成像(DWI)联合高分辨率T2加权成像(HR-T2WI)在直肠癌术前分期及环周切缘(CRM)评估价值。方法 选取80例经病理确诊为直肠癌患者,术前均接受多b值DWI、HR-T2WI检查,比较不同T、N分期及CRM性质患者多b值下表观弥散系数(ADC)差异。以病理组织学检查为金标准,采用Kappa一致性检验多b值DWI联合HR-T2WI诊断结果与病理组织学诊断结果的一致性。结果 T1分期6例,T2分期20例,T3分期32例,T4分期22例;N0分期41例,N1分期23例,N2分期16例;CRM阴性49例,阳性31例。多b值下T1分期患者ADC高于T2、T3、T4分期,且T2分期高于T3、T4分期,T3分期高于T4分期,差异有统计学意义(P<0.05)。多b值下N0分期患者ADC高于N1、N2分期,N1分期高于N2分期,差异均有统计学意义(P<0.05);CRM阴性ADC高于阳性,差异有统计学意义(P<0.05)。HR-T2WI诊断4例T1分期,22例T2分期,31例T3分期,23例T4分期。HR-T2WI检出36例N0分期,28例N1分期,16例N2分期。经Kappa一致性检验显示,HR-T2WI诊断T分期、N分期、CRM性质结果与病理组织学结果存在较强一致性(Kappa=0.730、0.781、0.688,P<0.001)。多b值DWI联合HR-T2WI诊断5例T1分期,23例T2分期,31例T3分期,21例T4分期。多b值DWI联合HR-T2WI诊断39例N0分期,24例N1分期,17例N2分期。结论 多b值DWI联合HR-T2WI对直肠癌术前分期、CRM性质具有良好的诊断价值。

A discussion on the application of b-value to the prediction of seismic tendency

In the estimation of seismic tendency, using Gutenberg-Richters b-value and using Hurst exponent are two com-monly used methods. Based on the fractal geometry of earthquake time series, we point out that these two methods correlate to each other. In the perspective of fractional Brownian motion (FBM), an earthquake sequence with b>3/4 and that with b<3/4 have different dynamic properties.

Continuous-cyclic variations in the b-value of the earthquake frequency-magnitude distribution

Seismicity of the Earth （M ≥ 4.5） was compiled from NEIC, IRIS and ISC catalogues and used to compute b-value based on various time windows. It is found that continuous cyclic b-variations occur on both long and short time scales, the latter being of much higher value and sometimes in excess of 0.7 of the absolute b-value. These variations occur not only yearly or monthly, but also daily. Before the occurrence of large earthquakes, b-values start increasing with variable gradients that are affected by foreshocks. In some cases, the gradient is reduced to zero or to a negative value a few days before the earthquake occurrence. In general, calculated b-values attain maxima 1 day before large earthquakes and minima soon after their occurrence. Both linear regression and maximum likelihood methods give correlatable, but variable results. It is found that an expanding time window technique from a fixed starting point is more effective in the study of b-variations. The calculated b-variations for the whole Earth, its hemispheres, quadrants and the epicentral regions of some large earthquakes are of both local and regional character, which may indicate that in such cases, the geodynamic processes acting within a certain region have a much regional effect within the Earth. The b-variations have long been known to vary with a number of local and regional factors including tectonic stresses. The results reported here indicate that geotectonic stress remains the most significant factor that controls b-variations. It is found that for earthquakes with Mw ≥ 7, an increase of about 0.20 in the b-value implies a stress increase that will result in an earthquake with a magnitude one unit higher.

Spatial Variations of b-Values in the Coastal Area of Guangdong

We used earthquake catalogs recorded by Guangdong Seismological Network from 2008 to 2014 to resolve the spatial variations of b-values in the coastal area of Guangdong, particularly in three key research areas(Yangjiang, Heyuan, and offshore Nanao Island) with strong seismicity. Our results revealed that b-values exhibited significant spatial variations, and zones with low b-values could indicate the most likely seismogenic area of large earthquakes. We observed three clear low b-value patches in the offshore Nanao Island. We found a distinct high b-value peak at the depth of 11 km and two minimum peaks at about 14 and 7–8 km in the Yangjiang area. The overall b-values generally decrease with depth in the Heyuan area. The spatial variations of b-values reflect tectonic anomalies; that is, the ‘low-high-low' distribution of b-values in the offshore Nanao Island and the Yangjiang area may indicate the anomaly of the crustal structure with a weak layer. The b-values of reservoir-induced seismicity are obviously lower than that induced by tectonism. This finding indicates that the reservoir area is generally at high stress state under the condition of high pore pressure. We inferred that large earthquakes might be prone to occur at 10–12 km depth in the offshore Nanao Island, at 12–15 km depth in the Yangjiang area, and at the lower part of the seismic activity zone in the Heyuan area. Moreover, the upstream area of the Xinfengjiang reservoir is the most likely area of future large earthquakes in the Heyuan area.

Atomic Decompositions of Weak Hardy Spaces of B-Valued Martingales

The atomic decompositions of weak Hardy spaces of Banach-space-valued martingales are given. With the help of the atomic decompositions, some inequalities for B-valued martingales are established in the case 0〈r≤1. Here the results are connected closely with the p-uniform smoothness and q-uniform convexity of Banach spaces which the martingales take values in.

Correcting the Gutenberg–Richter b-value for effects of rounding and noise

The effects of magnitude rounding and of the presence of noise in the rounded magnitudes on the estimation of the Gutenberg-Richter b-value are explored, and the ways to correct for these effects are proposed. For typical values, b = 1 and rounding interval △M = 0.1, the rounding error is approximately -10^-3 and it can be corrected to a negligible approximately -10^-5. For the same typical values, the effect of noise can be larger, depending on the characteristics of the noise distribution; for normally distributed noise with standard deviation σ = 0.1, the correct b-value may be underestimated by a factor - 0.97.

The b-value and fractal dimension of local seismicity around Koyna Dam(India)

Earthquakes began to occur in Koyna region （India） soon after the filling of Koyna Dam in 1962. In the present study, three datasets 1964-1993, 1993-1995, and 1996-1997 are analyzed to study the b-value and fractal dimension. The b-value is calculated using the Gutenberg- Richter relationship and fractal dimension Dcorr. using correlation integral method. The estimated b-value and Dcorr. of this region before 1993 are found to be in good agreement with previously reported studies. In the sub- sequent years after 1995, the b-value shows an increase. The estimated b-values of this region are found within the limits of global average. Also, the pattern of spatial clustering of earthquakes show increase in clustering and migration along the three zones called North-East Zone, South-East Zone （SEZ）, and Warna Seismic Zone. The earthquake events having depth ≤5 km are largely confined to SEZ. After 1993, the Dcorr. shows decrease, implying that earth- quake activity gets clustered. This seismic clustering could be helpful for earthquake forecasting.

The spatiotemporal variation of the b-value and its tectonic implications in North China

In this study, we adopt an improved Bayesian approach based on free-knot B-spline bases to study the spatial and temporal distribution of the b-value. Synthetic tests show that the improved Bayesian approach has a superior performance compared to the Bayesian approach as well as the widely used maximum likelihood estimation （MLE） method in fitting the real variation of b-values. We then apply the improved Bayesian approach to North China and find that the b-value has a clear relevance to seismicity. Temporal changes of b-values are also investigated in two specific areas of North China. We interpret sharp decreases in the b-values as useful messages in earthquake hazard analysis.

BOUNDEDNESS OF DYADIC DERIVATIVE AND CESARO MEAN OPERATOR ON SOME B-VALUED MARTINGALE SPACES

In this article, it is proved that the maximal operator of one-dimensional dyadic derivative of dyadic integral I＊ and Cesàro mean operator σ＊ are bounded from the B-valued martingale Hardy spaces pΣα, Dα, pLα, p H#α, pKr to Lα （0 α ∞）, respectively. The facts show that it depends on the geometrical properties of the Banach space.

Diffusion-weighted Single-shot Echo Planar MR Imaging of Normal Human Prostate Using Different b Values

This study examined the effect of different b values on diffusion-weighted MR imaging （DWI） of human prostate by using single-shot spin echo echo planar imaging （SE-EPI） sequences, observed the normal appearances and measured apparent diffusion coefficient （ADC） values in anatomical regions of normal prostate. Twenty-four healthy volunteers （mean age： 32 y） were studied by using a 1.5T system with a phased array surface multicoil. Two kinds of single-shot SE-EPI sequence were used to perform DWI in the prostate in volunteers, with five b values being 0, 30, 300, 500 to 1000 s/mm2. The image quality with different imaging parameters was analyzed and the ADC values in anatomical regions of normal prostate were measured. DWI of prostate was successfully obtained in all volunteers. The images were of good quality, without artifacts containing pixels within the prostate. The contrast was good between the different anatomical regions of the prostatic gland, i.e., the peripheral zone （PZ）, which exhibited higher signal intensity, and the central gland （CG）. Signal intensity contrast was related to the magnitude of b values. The ADC values in PZ and CG were （1.27±0.22）×10-3 mm2/s and （1.01±0.17）×10-3 mm2/s,respectively. The ADC values were found to be significantly higher in PZ than in CG （P〈0.05, paired t-test）. Significant differences were found between the slice-selecting component and both the read-out and phase-encoding components of the ADC values. It is concluded that SE-EPI is a suitable DWI sequence for human prostate. The contrast between PZ and CG is good when b values are low, while the diffusion and ADC values are accurate when b values are high. ADC values are higher in PZ than in CG in normal prostate. Diffusional anisotropy is present in normal prostatic tissue.

Calculation of b value and its application in earthquake prediction

The improved calculation method of b value is presented in tills paper. The method can enlarge the role of earthquake occurrence frequency in b value calculation and thus increase the b value variation amplitude. In this case,the combination structure variation between earthquake magnitudes and corresponding frequencies could be shown clearly. According to the calculation and analysis for limited mainshocks in the complete seismicity data of selected monitored area with assigned consistent lowest magnitude, the precursor anomaly features, quantitative indexes and the calculation formula of relative subject function of b value variation have been preliminarily worked out. The prediction in short period (from 1 to 3 months) for damage earthquakes in the monitored area mentioned above can be put forward on the basis of the results of quantitative calculation and analysis.

An experimental study on variation of b value during deformation of rock samples with different structural models

A preliminary study of b value of rocks with two kinds of structural models has been made on the base of a new acoustic emission recording system. It shows that b value of the sample decreases obviously when the sample with compressive en echelon faults changes into a tensile one after interchange occurs between stress axis σ1 and σ2. A similar experiment is observed when the sample with tensile en echelon faults changes into that with a bend fault after two segments of the en echelon fault linking up. These facts indicate that the variation of b value may con-tain the information of the regional dominant structural model. Therefore, b-value analyses could be a new method for studying regional dominant structural models.

The Analysis of B2B Business Model from the Viewpoint of Value Chain

Electronic business impacts differently the busines s process in or between the corporations in variant degree. In view of the new fea tures of the internet, critical questions to be answered inclued: what are t he emerging business models and related to this, which strategic marketing appro aches are applied,or emerging. In the paper, the business models in B2B are clas sified into four types as e-procurement, e-marketplace, e-trade exchange, and collaborative trading community from the value viewpoint.And then the paper giv es the measure among the four business models by providing a framework that has been developed on the basis of current commercial Internet business and experime ntal work. The difference between the value chain in traditional commerce and th e one in e-business is compared. And we give the success factors by a case stud y and the barriers to electronic business in the developing B2B business model.

3.0T常规MRI联合多b值DWI在前列腺癌诊断中的价值

目的 探究3.0T常规MRI联合多b值弥散加权成像(diffusion weighted imaging,DWI)应用在前列腺癌诊断中的价值。方法 回顾性分析,依据穿刺或手术病理结果将患者分前列腺癌组(n=32)与前列腺增生组(n=33),所有患者行3.0T常规MRI、常规MRI+多b值DWI检查(b值分别为1000s·mm^(-2)、2000s·mm^(-2)与3000s·mm^(-2)),计算两种检查的诊断准确率、特异度和敏感度并进行比较,不同b值DWI检查中前列腺增生组及前列腺癌组ADC值的比较,前列腺癌组癌灶与对侧或周围正常组织不同b值DW I信号强度差值、DWI信号强度对比度比较,以及不同b值DWI检查中癌灶ADC值比较。结果3.0T常规MRI+多b值DWI检查准确率、特异度和敏感度均显著高于常规M RI检查技术,(P<0.05);不同b值DWI检查中前列腺增生组的ADC值均高于前列腺癌组,差异有统计学意义(P<0.05);不同b值前列腺癌组与对侧正常组织DWI信号强度差值、DWI信号强度对比度有显著差别(P<0.05),随着b值升高DWI信号强度差值减小、DWI对比度升高;不同b值检查中癌灶的ADC值有显著差异(P<0.05),随着b值升高ADC值下降。结论 3.0T MRI多b值DWI联合应用技术有助于前列腺癌及增生的鉴别诊断,具有较高临床实用价值。

Analysis of Spatial and Temporal Variation Characteristics of the bvalue in the Hetao Seismic Belt

Focusing on the b-value as the research target and under the theoretical framework that the b-value is determined by stress state and medium properties, the variation characteristics of the b-value in the Hetao seismic belt are analyzed. Earthquakes with ML≥1. 5,which have occurred in the Hetao seismic belt since 1970 are selected to conduct the quantitative detection of the non-uniform temporal change of Mcusing the EMR method. Based on the actual situation of seismic activity,the lower limit magnitude is set as ML2. 0 to calculate the b-value. The temporal variation of the b-value is calculated and scanned using the least square method. The results show that there is a good corresponding relationship between the temporal variation of the b-value,strong earthquake activity,network distribution and aftershock deletion. We also calculate and scan the spatial variation of the b-value by using maximum likelihood. The results show that the spatial difference is possibly caused by stress state and crustal medium properties. The tectonic dependence of the b-value is obvious. In addition,the sufficient earthquakes samples in each magnitude interval are still a key step to improve the calculation accuracy of the b-value.

Existence of Solutions for a Multi-point Boundary Value Problems with Three Dimension Kernal at Resonance

In this paper,a multi-point boundary value problems for a three order nonlinear deferential equation is considered.With the help of coincidence theorem due to Mawhin,a existence theorem is obtained.