Soil Macropore Structure Characterized by X-Ray Computed Tomography

Undisturbed soil core with many macropores and disturbed soil core with onlyone macropore (diameter is 10 mm) were probed by X-ray computed tomography (CT). The size, number,shape and continuity of macropores in the transverse and vertical sectionsof soil were characterizedusing CT scanning images. The probability densities of macropores in the transverse section of soilcore exhibited a logarithmic P distribution. Results indicated that CT scanning was a promisingnondestructive method for characterizing macropores in soils.

Studies of Microstructure of Kernels of Macadamia integrifolia and Its Hybrids through MRI, X-Ray Tomography and Confocal Microscopy

The aim of this study was to apply the existing techniques that enable examination ofmacadamia kernels to provide a better understanding of physico-chemical properties of kernels during postharvest processing. These techniques, such as X-ray tomography, could be applied for quality monitoring in the macadamia industry. The objectives of this study were to investigate the browning centre symptoms that usually occur in macadamia nuts-in-shell. The applied techniques included confocal microscopy, X-ray tomography and magnetic resonance imaging （MRI）. Five different varieties of macadamia nuts （A38, 246, 816, 842 and Daddow） were selected to include distinct characteristics, such as drop pattern and growing location. Analysis of the microstructure of kernels by confocal microscopy showed the distribution of possible brown pigment compounds as well as the distribution of lipids, carbohydrates and proteins inside macadamia cells. Physical properties data, including shell density and seed to volume ratio, were obtained by X-ray tomography. Magnetic resonance diffusion tensor imaging used in this study showed marked differences in microstructure which indicate that different varieties exhibit different microstructures expressed as fraction ofanisotropy and apparent diffusion coefficient that appear to be related to the occurrence of the brown centre. Hence, the findings of this study have potential to improve the existing postharvest techniques used in the macadamia processing industry. They will be of benefit to the industry in terms of improved quality control and cost reduction.

结直肠癌肝转移灶超声造影与CT影像表现的比较

目的:比较结直肠癌肝转移灶超声造影与增强CT血流灌注的异同。方法:对比60例60个结直肠癌肝转移灶超声造影与增强CT动脉期及门脉期的增强表现。结果:60个病灶超声造影动脉期均增强,53.3%(32/60)周边增强,46.7%(28/60)整体增强;增强CT见78.3%(47/60)的病灶周边增强,16.7%(10/60)整体增强,5%(3/60)未见增强(P<0.01)。动脉期病灶的增强程度方面,超声造影示93.3%(56/60)的病灶增强程度高于肝实质,6.7%(4/60)增强程度低于肝实质;增强CT示91.2%(52/57)的病灶增强程度高于肝实质,8.8%(5/57)增强程度低于肝实质(P>0.05);门脉期,超声造影示100%(60/60)的病灶增强减退,较周围肝实质呈低回声,增强CT门脉期示100%(60/60)的病灶较周围肝实质呈低密度,两种影像方法所示的转移灶增强程度均低于肝实质(P>0.05)。结论:结直肠癌肝转移灶的超声造影和增强CT增强表现不完全相同,超声造影在反映部分结直肠癌肝转移灶动脉血流灌注方面较增强CT有一定优势。

螺旋CT阴茎动脉成像技术和临床应用价值

目的 :探讨螺旋CT阴茎动脉成像技术和临床应用价值。方法 :对 18例血管性阳萎患者行螺旋CT容积扫描 ,图像经后处理获得阴部动脉立体图像。结果 :①螺旋CT阴茎动脉成像图像的质量与扫描方法、图像重建方法等密切相关 ;②三维图像可以清晰显示髂内动脉、阴部内动脉、阴茎海绵体动脉的分支、走行 ;③ 6例动脉性阳萎者 ,阴茎动脉成像可见病变位于阴部内动脉 3例 ,阴茎海绵体动脉 3例。结论 :螺旋CT阴茎动脉成像可以多方位观察 ,从二维及三维立体图像上获得更多诊断信息 。

脑星形细胞瘤动态CT指标与微血管密度的关系

目的 探讨脑星形细胞瘤动态CT扫描与微血管密度 (MVD)的关系。方法 收集动态CT扫描资料完整、手术病理证实的脑星形细胞瘤 3 8例 ,并根据动态CT扫描产生的时间 密度曲线分析瘤组织的TBRp、TBRL、Sa(曲线升段斜率 )、AR(动态曲线下面积 )。同时对切除的瘤组织标本采用免疫组织化学技术标记微血管 ,测定微血管密度 ,并将其与时间 密度曲线分析结果相对照。结果 星形细胞瘤的MVD与其病理级别、患者复发密切相关。TBRp、TBRL、Sa、AR在Ⅲ～Ⅳ级星形细胞瘤与Ⅰ、Ⅱ级之间相差显著(P <0 0 5 ,P <0 0 1) ,而且均与MVD呈正相关 (P <0 0 5 )。结论 活体动态CT反映星形细胞瘤的血管生成活性是可行的。认真分析星形细胞瘤的时间

磁共振张量成像对闭合性隐匿肝损伤诊断价值分析

目的 探讨磁共振张量成像(Diffusion tensor imaging,DTI)对闭合性隐匿肝损伤的诊断价值。方法 回顾性分析闭合性隐匿肝损伤患者43例,分析其DTI不同时间段(48h、72h及7d)影像变化特点,平均扩散系数(average diffusion coefficient,DCavg)及各向异性系数(fractional anisotropy,FA)值、肝酶(AST/ALT)变化规律及其之间相关性。采用SPSS22.0软件进行统计分析,以P<0.05为差异有统计学意义。结果 闭合性隐匿肝损伤表现肝实质内信号不均(T_(2)WI/DTI示高信号),DTI诊断闭合性隐匿肝损伤阳性率显著高于T_(2)WI/T_(1)WI(χ^(2)=24.08,P<0.01)及AST/ALT (χ^(2)=4.49,P<0.05);DCavg(b=100、 300 s/mm^(2))于24h、48h组与对照组比较均显著性升高(P<0.05);而FA(b=100、300、600s/mm^(2))值呈下降趋势,对照组与24h、48h、7d组均存在显著性差异(P<0.05);DCavg与AST间存在高度负相关(b=100s/mm^(2),R=-0.71,P<0.01), FA与AST、ALT间均亦存在显著负相关(b=300s/mm^(2),R=-0.70,P<0.01)。结论 DTI能较早的发现闭合性肝损伤肝内隐匿性病灶,其参数Dcavg及FA客观反映闭合性隐匿肝损伤的病理变化特点,对闭合性隐匿肝损伤的准确诊断具有重要的临床价值。

Computed tomography perfusion in evaluating the therapeutic effect of transarterial chemoembolization for hepatocellular carcinoma

AIM： To prospectively assess the changes in parameters of computed tomography （CT） perfusion pre- and post-transarterial chemoembolization （TACE） of hepatocellular carcinoma （HCC） in different treatment response groups, and to correlate the changes with various responses of HCC to TACE. METHODS： Thirty-nine HCC patients underwent CT perfusion examinations pre-（1 d before TACE） and post-treatment （4 wk after TACE）. The response evaluation criteria for solid tumors （RECIST） were referred to when treatment responses were distributed. Wilcoxon-signed ranks test was used to compare the differences in CT perfusion parameters pre- and post- TACE for different response groups. RESULTS： Only one case had treatment response to CR and the CT perfusion maps of post-treatment lesion displayed complete absence of signals. In the PR treatment response group, hepatic artery perfusion （HAP）, hepatic arterial fracture （HAF） and hepatic blood volume （HBV） of viable tumors post-TACE were reduced compared with pre-TACE （P = 0.001, 0.030 and 0.001, respectively）. In the SD group, all CT perfusion parameters were not significantly different pre- and post-TACE. In the PD group, HAP, HAl=, portal vein perfusion （PVP） and hepatic blood flow （HBF） of viable tumors post-TACE were significantly increased compared with pre-TACE （P = 0.005, 0.012, 0.035 and 0.005, respectively）. CONCLUSION： Changes in CT perfusion parameters of viable tumors are correlated with different responses of HCC to TACE. Therefore, CT perfusion imaging is a feasible technique for monitoring response of HCC to TACE.

Assessment of hepatic functional reserve by cirrhosis grading and liver volume measurement using CT

AIM： To explore a method for quantitative assessment of hepatic functional reserve by combining computed tomography （CT） volumetry with CT grading of liver cirrhosis before liver resection in patients with hepatocellular carcinoma. METHODS： CT images of 55 patients undergoing liver resection were studied prospectively. The degree of liver cirrhosis was referred as ＂CT grade＂ and the percentage of remnant liver volume （PRLV） [PRLV = predicted RLV/predicted total liver volume （PTLV） × 100%; PTLV （mL） = 121.75 ＋ 16.49 × body mass （kg）] were calculated by adding slice by slice of CT liver images. The postoperative RLV, pathologic stages of liver fibrosis in non-tumor area and survival time in these cases were analyzed. RESULTS： There was a significant difference in survival time between the group with PRLV ≤ 50% and the group with PRLV 〉 50% （X^2= 4.988, P = 0.026）, and between the group with CT grade 0/1 and the group with CT grade 2/3 （X^2= 5.429, P = 0.026）. With combination of the both parameters, an oblique line was identified according to the distribution of 32 survivors versus 23 deceased subjects. The mortality rate above the line was 7.1% （1/14）, and that below the line was 53.7% （22/41）, indicating a significant difference between the two rates （X^2 = 9.281, P = 0.002, P 〈 0.05）. CONCLUSION： PRLV and CT grades are significantly correlated with hepatic functional reserve. The predicted line using these two parameters is useful in candidates undergoing liver resection for judging hepatic functional reserve.

^(18)F-DG PET/CT in detection of recurrence and metastasis ofcolorectal cancer

AIM: To evaluate the value of 18F-DG PET/CT in detecting recurrence and/or metastasis of colorectal cancer (CRC). METHODS: Combined visual analysis with semiquantitative analysis, the 18F-DG PET/CT whole- body imaging results and the corresponding clinical data of 68 postoperative CRC patients including 48 male and 20 female with average age of 58.1 were analyzed retrospectively. RESULTS: Recurrence and/or metastasis were confirmed in 56 patients in the clinical follow-up after the PET/CT imaging. The sensitivity of PET/CT diagnosis of CRC recurrence and/or metastasis was 94.6%, and the specificity was 83.3%. The positive predictive value (PPV) was 96.4% and the negative predictive value (NPV) was 76.9%. PET/CT imaging detected one or more occult malignant lesions in 8 cases where abdominal/pelvic CT and/or ultrasonography showed negative findings, and also detected more lesions than CT or ultrasonography did in 30.4% (17/56) cases. Recurrence and/or metastasis was detected in 91.7% (22/24) cases with elevated serum CEA levels by 18F-DG PET/CT imaging. CONCLUSION: 18F-DG PET/CT could detect the recurrence and/or metastasis of CRC with high sensitivity and specificity.

Calcified reticulate rind sign:A characteristic feature of gossypiboma on computed tomography

We herein report a gossypiboma resulting from a retained surgical swab, which had been left in peritoneum for 20years after appendectomy. CT revealed a cystic mass with a calcified reticulate rind. Subsequent surgery and pathological examination showed a gossypiboma. A simple experiment, using a barium-soaked surgical swab demonstrating similar CT appearance, supported our postulation that calcium deposition on the reticulated fibers of a surgical swab could generate such a characteristic 'calcified reticulate rind' sign. We believe that identification of this CT sign facilitates the diagnosis of gossypibomas.

Highly metabolic thrombus of the portal vein:^(18)F fluorodeoxyglucose positron emission tomography/computer tomography demonstration and clinical significance in hepatocellular carcinoma

AIM： To assess the ability of ^18F-fluorodeoxyglucose positron emission tomography/computer tomography （^18F-FDG PET/CT） to differentiate between benign and malignant portal vein thrombosis in hepatocellular carcinoma （HCC） patients.METHODS： Five consecutive patients who had HBV cirrhosis, biopsy-proven HCC, and thrombosis of the main portal vein and/or left/right portal vein on ultrasound （US）, computer tomography （CT） or magnetic resonance imaging （MRI） were studied with ^18F-FDG PET/CT. The presence or absence of a highly metabolic thrombus on ^18F-FDG PET/CT was considered diagnostic for malignant or benign portal vein thrombosis, respectively. All patients were followed-up monthly with US, CT or MRI. Shrinkage of the thrombus or recanalization of the vessels on US, CT or MRI during follow-up was considered to be definitive evidence of the benign nature of the thrombosis, whereas enlargement of the thrombus, disruption of the vessel wall, and parenchymal infiltration over follow-up were considered to be consistent with malignancy. ^18SF-FDG PET/CT, and US, CT or MRI results were compared.RESULTS： Follow-up （1 to 10 mo） showed signs of malignant thrombosis in 4 of the 5 patients. US, CT or MRI produced a true-positive result for malignancy in 4 of the patients, and a false-positive result in 1. ^18F-FDG PET/CT showed a highly metabolic thrombus in 4 of the 5 patients. ^18F-FDG PET/CT achieved a true-positive result in all 4 of these patients, and a true-negative result in the other patient. No false-positive result was observed using ^18F-FDG PET/CT.CONCLUSION： ^18F-FDG PET/CT may be helpful in discriminating between benign and malignant portal vein thrombi. Patients may benefit from ^18F-FDG PET/CT when portal vein thrombi can not be diagnosed exactly by US, CT or MRI.

Segmental radiofrequency ablation of pulmonary vein ostia for patients with refractory paroxysmal atrial fibrillation using multi-slice spiral computed tomography guidance

Objective： To evaluate the safety and clinical efficacy of segmental radiofrequency ablation of pulmonary vein （PV） ostia for patients with refractory paroxysmal atrial fibrillation （AF） under multi-slice spiral computed tomography （MSCT） guidance before the procedure. Methods： A series of 58 consecutive patients with refractory paroxysmal AF were enrolled to undergo segmental radiofrequency ablation ofPV ostia. The 36 male and 22 female patients with mean age of （57.4±9.5） （32-79） years and no obvious organic heart disease. Before ablation, patients received MSCT to generate 3-dimentional image of the left atrium （LA） and proximal PVs. Patients then underwent segmental radiofrequency ablation ofPV ostia using PV circular mapping catheter manipulated several times to ensure complete isolation between PVs and LA. Results： No complications occurred during the procedure. One patient developed delayed cardiac tamponade, which was drained percutaneously. The mean follow-up time was （17.1±9.3） months. Forty-one patients （95%） experienced improved quality of life one month after the procedure. Thirty-six patients （83%） showed stable sinus rhythm, while 10 patients （23%） required additional anti-arrhythmic drugs. AF returned≥1 time in 6 （14%） patients who underwent anti-arrhythmic drug therapy, but the number of episodes was less than that before the procedure. However, one patient experienced recurrent episodes of atrial flutter. Conclusion： It is safe and effective to perform segmental radiofrequency ablation of PV ostia for patients with refractory paroxysmal AF using MSCT guidance mappening.

肝脏血管平滑肌脂肪瘤螺旋CT表现

目的:探讨肝脏血管平滑肌脂肪瘤(hepatic angiomyolipoma,HAML)的CT诊断及鉴别诊断。材料与方法:回顾性分析10例经过穿刺或者手术病理证实的HAML的临床及CT表现。结果:10例病灶位于肝右叶8例,肝左叶2例,其中脂瘤型5例,血管瘤型3例,肌瘤型1例和混合型1例。脂瘤型CT平扫示肿瘤组织密度与脂肪相似,CT值-40^-60Hu,其内可见软组织密度病灶,软组织密度病灶强化明显。3例血管瘤型CT平扫呈低密度,增强动脉期肿瘤明显均质强化,门静脉期仍高于同期肝实质的强化,延迟期呈低密度。1例肌瘤型和1例混合型平扫呈稍低密度软组织肿块,其内密度常不均匀,增强动脉期肿瘤强化较明显,门静脉期仍持续强化,其密度等于同期肝实质密度。结论:不同病理组织类型的HAML,CT表现有所不同,认识这些征像有助于减少该病术前误诊率。

Alpha-fetoprotein-producing colon cancer with atypical bulky lymph node metastasis

Alpha-fetoprotein (AFP)-producing colorectal cancer is extremely rarely reported until now. All of the reported cases harboring synchronous hematogenous spread including liver and/or lung metastasis had a poor prognosis and died within 12 mo. We here describe a 71-year old man with AFP-producing colon cancer who presented with an unusual bulky lymph node metastasis instead of hematogenous spread. He underwent adjuvant chemotherapy in addition to curative surgical resection, which prolonged his survival.

A novel technique of three-dimensional reconstruction segmentation and analysis for sliced images of biological tissues

A novel technique of three-dimensional (3D) reconstruction, segmentation, display and analysis of series slices of images including microscopic wide field optical sectioning by deconvolution method, cryo-electron microscope slices by Fou-rier-Bessel synthesis and electron tomography (ET), and a series of computed tomography (CT) was developed to perform si-multaneous measurement on the structure and function of biomedical samples. The paper presents the 3D reconstruction seg-mentation display and analysis results of pollen spore, chaperonin, virus, head, cervical bone, tibia and carpus. At the same time, it also puts forward some potential applications of the new technique in the biomedical realm.

A case of multiple intra-abdominal splenosis with computed tomography and magnetic resonance imaging correlative findings

Hepatic splenosis refers to heterotopic auto- transplantation and implantation of splenic tissue resulting from the spillage of cells from the spleen after splenic trauma or splenectomy. The true incidence of splenosis is unknown, because this entity is usually an incidental finding at surgery. Splenic implants are usually multiple, and can be localized anywhere in the peritoneal cavity. Splenic implants in the peritoneal cavity may be confused with renal tumors, abdominal lymphomas and endometriosis. We describe computed tomography (CT) and magnetic resonance imaging (MRI) findings in a rare case of multiple intra-abdominal splenosis located along the hepatic surface and adjacent to the upper pole of the right kidney, mimicking a renal neoplasm.

Acute ulcerative jejunal diverticulitis:Case report of an uncommon entity

Jejunal diverticulosis is a rare entity with variable clinical and anatomical presentations.Its reported incidence varies from 0.05% to 6%.Although there is no consensus on the management of asymptomatic jejunal diverticular disease,some complications are potentially life threatening and require early surgical treatment.We report a case of an 88-year-old man investigated for acute abdominal pain with a high biological inflammatory syndrome.Inflammation of multiple giant jejunal diverticulum was discovered at abdominal computed tomography (CT).As a result of the clinical and biological signs of early peritonitis,an emergency surgical exploration was performed.The first jejunal loop showed clear signs of jejunal diverticulitis.Primary segmental jejunum resection with end-to-end anastomosis was performed.Histopathology report confirmed an ulcerative jejunal diverticulitis with imminent perforation and acute local peritonitis.The patient made an excellent rapid postoperative recovery.Jejunal diverticulum is rare but may cause serious complications.It should be considered a possible etiology of acute abdomen,especially in elderly patients with unusual symptomatology.Abdominal CT is the diagnostic tool of choice.The best treatment is emergency surgical management.

CORONARY ANGIOGRAPHY WITH DUAL SOURCE COMPUTED TOMOGRAPHY:INITIAL EXPERIENCE

Objective To explore the scan technique and image quality of coronary angiography with dual source computed tomography(CT) without oral metoprolol preparation.Methods Plain and enhanced dual source CT coronary angiography without oral metoprolol preparation was prospectively performed in 600 patients.Calcium scoring with plain scan images as well as multi-planar reconstruction(MPR),maximum intensity projection(MIP),and volume rendering technique(VRT) reconstruction with enhanced scan images were performed in all cases.The scan technique and post-reconstruction experience was summarized.The image quality was classified as 1 to 4 points,and coronary segments classified according to the American Heart Association standards were evaluated.Results The average calcium score of the 600 cases was 213.6±298.7(0-3 216.5).The average heart rate of the enhanced scan was 82.1±16.2(47-139) bpm.The post-reconstruction methods with which coronary segments could be shown as best as possible consisted of single phase reconstruction method,two or more phases supplemented method,and electrocardiogram editing method.Altogether 8 457 coronary segments were evaluated,among which 97.2% were evaluated as point 1,1.7% point 2,0.5% point 3,and 0.6% point 4.The coronary segments in 261 cases were completely normal,while 360 segments were diagnosed with <50% stenosis and 625 segments with ≥50% stenosis.Conclusions Excellent coronary artery image can be obtained with dual source CT in patients with any heart rate without oral metoprolol preparation.Heart rate is not a major source of the artifact,coronary segments can be well shown with single or multiple-phase reconstruction method.

Volumetric fraction measurement in oil-water-gas multiphase flow with dual energy gamma-ray system

Volumetric fraction distribution measurement is a constituent part of process tomography system in oil-water-gas multiphase flow. With the technological development of nuclear radial inspection, dual-energy γ-ray techniques make it possible to investigate the concentration of the different components on the cross-section of oil-water-gas multiphase pipe-flow. The dual-energy gamma-ray technique is based on materials attenuation coefficients measurement comprised of two radioactive isotopes of 241Am and 241Cs which have emission energies at 59.5 keV and 662 keV in this project. Nuclear instruments and data acquisition system were designed to measure the material’s attenuation dose rate and a number of static tests were conducted at the Multiphase Laboratory, Institute of Mechanics, Chinese Academy of Sciences. Three phases of oil-water-gas media were inves- tigated for their possible use to simulate different media volumetric fraction distributions in experimental vessels. Attenuation intensities were measured, and the arithmetic of linear attenuation coefficients and the equations of volumetric fractions were studied. Investigation of an unexpected measurement error from attenuation equations revealed that a modified arithmetic was involved and finally the system achieved acceptable accuracy in experimental research.

Imaging technologies in oilfield applications

In this paper, we describe some recent imaging technologies developed by Schlumberger for oilfield downhole mul- tiphase flow production logging (PL) and cross-well electromagnetic (EM) survey applications. FloScan Imager (FSITM) has been introduced as a 3-phase oil/gas/water flow PL tool for deviated and horizontal wells. FSI sensors can map fluid velocity and holdup profiles along a vertical diameter of the wellbore at every survey depth, enabling a robust estimate of the individual phase flow rates in complex flow regimes. The cross-well EM survey is based on cross-borehole induction logging technique and provides resistivity distribution at a reservoir scale. It is a useful tool for reservoir management and is most effective in dynamic fields where fluid saturations are variable in time and space. The tool can be used to identify (water or steam) flooded and bypassed regions. By monitoring changes in the resistivity spatial distribution with time, cross-well EM survey is very effective at mapping inter-well temperature and structure. Some field examples are shown for both FloScan Imager PL tool and cross-well resistivity imaging survey.