Comparison of Bayesian penalized likelihood reconstruction versus OS-EM for characterization of small pulmonary nodules in oncologic PET/CT

Objective

To determine whether the recently introduced Bayesian penalized likelihood PET reconstruction (Q.Clear) increases the visual conspicuity and SUV_max of small pulmonary nodules near the PET resolution limit, relative to ordered subset expectation maximization (OS-EM).

Methods

In this institutional review board-approved and HIPAA-compliant study, 29 FDG PET/CT scans performed on a five-ring GE Discovery IQ were retrospectively selected for pulmonary nodules described in the radiologist’s report as “too small to characterize”, or small lung nodules in patients at high risk for lung cancer. Thirty-two pulmonary nodules were assessed, with mean CT diameter of 8 mm (range 2–18). PET images were reconstructed with OS-EM and Q.Clear with noise penalty strength β values of 150, 250, and 350. Lesion visual conspicuity was scored by three readers on a 3-point scale, and lesion SUV_max and background liver and blood pool SUV_mean and SUV_stdev were recorded. Comparison was made by linear mixed model with modified Bonferroni post hoc testing; significance cutoff was p < 0.05.

Results

Q.Clear improved lesion visual conspicuity compared to OS-EM at β = 150 (p < 0.01), but not 250 or 350. Lesion SUV_max was increased compared to OS-EM at β = 150 and 250 (p < 0.01), but not 350.

Conclusion

In a cohort of small pulmonary nodules with size near an 8 mm PET full-width half maximum, Q.Clear significantly increased lesion visual conspicuity and SUV_max compared to our standard non- time-of-flight OS-EM reconstruction, but only with low noise penalization. Q.Clear with β = 150 may be advantageous when evaluation of small pulmonary nodules is of primary concern.

     

肾脏嗜酸细胞瘤的CT诊断

分析肾嗜酸细胞瘤的ＣＴ表现及其病理基础，以提高对此瘤的认识。材料与方法：２例肾嗜酸细胞瘤经病理诊断，术前均行ＣＴ平扫及增强扫描。结果；２例为单发肿瘤，直径为４．８ｃｍ及５．０ｃｍ。     

应用白芨建立门静脉高压动物模型

目的寻求制作门静脉高压动物模型的最佳方法，并以此为基础从事肝硬化后门静脉血液动力学基础研究。方法以3组共15只兔为动物模型，分别以0.2％、0．4％、0.8％浓度的白芨粉为栓塞材料，开腹注入兔门静脉内，手术前后行门静脉测压、血管造影及病理学检查，最长观察时间阎周.结果以0．4％浓度白芨粉制作门静脉高压模型最佳，4周后肝脏体积缩小20％，门静脉压平均升高40％，病理呈典型坏死后肝硬化表现。结论以白芨粉为栓塞材料制作肝硬化门静脉高压动物模型方法简单、效果可靠已重复性好.以不同浓度的白芨栓塞剂来控制坏死后肝纤维化的程度是本试验的一大特点,本动物模型的建立对深入研究肝硬化门静脉高压的成因及治疗措施有着重要意义。     

听骨链和迷路螺旋CT三维重建技术初步临床应用报告

目的探讨听骨链和迷路螺旋ＣＴ三维重建技术的临床应用和局限性。方法采用薄层螺旋扫描（层厚１．０ｍｍ）、小视野（ＦＯＶ＝５ｃｍ）、密集重建（间隔０．１ｍｍ）技术，对１４例正常和１５例中耳病变患者行听骨链和迷路三维重建成像，包括多平面重组（ＭＰＲ）、最小密度或最大密度投影（ＭｉｎＩＰ或ＭａｘＩＰ）和表面成像（ＳＳＤ）。结果１４例正常患者中对其中１３例听骨链及８例迷路进行三维重建，听骨链重建显示锤骨柄和砧骨长突平行共同指向蜗岬，砧镫关节呈“Ｌ”形影，迷路三维重建显示耳蜗和三个半规管。１３例中耳炎患者中９例胆脂瘤形成，显示听骨链不同程度的破坏，２例先天中耳畸形显示听骨链发育异常。结论螺旋ＣＴ三维重建技术有利于中耳畸形和其他耳部病变的诊断，但尚存在重建时间长、损失部分信息等缺点，有待进一步改善。     

儿童腹腔脓肿的CT诊断

目的探讨ＣＴ对儿童腹腔脓肿的诊断价值。方法对２３例经手术和穿刺针吸证实的腹腔脓肿的ＣＴ表现进行分析，急性阑尾炎１３例，升结肠穿孔１例，美克尔憩室炎２例，感染源不明确７例。１９例行平扫与增强检查，４例仅平扫检查。结果脓液ＣＴ值与病程及致病菌种类无关，脓液量与病程呈正相关。５２％脓肿内见到气体影，２２％脓肿内见到小钙化斑。病程１周以上者全部见不均匀厚壁强化的脓肿壁。结论脓肿内见到小钙化斑和气体影像具有特征性，脓腔内较大气液平面提示肠瘘存在，脓肿内无气体影不能排除肠瘘。     

Antegrade internal ureteral stenting: a technical refinement

A pliable, easy to place, double pigtail, internal ureteral stent made of elastomeric polyurethane is described. The tapered distal pigtail end minimizes bladder irritation and the combination of a pusher and absorbable suture enables optimal placement of the proximal pigtail end in the renal pelvis. Ten stents used in eight patients remained functional without bladder irritation for a mean period of 8 months (range, 2-14 months).     

Prevalence of Hepatitis C Infection in New York City, 2004

Hepatitis C virus (HCV) is the leading cause of chronic liver disease in the United States. Accurate hepatitis C prevalence estimates are important to guide local public health programs but are usually unavailable to local health jurisdictions. National surveys may not reflect local variation, a particular challenge for urban settings with disproportionately large numbers of residents in high-risk population groups. In 2004, the New York City Department of Health and Mental Hygiene conducted the NYC Health and Nutrition Examination Survey, a population-based household survey of non-institutionalized NYC residents ages 20 and older. Study participants were interviewed and blood specimens were tested for antibody to HCV (anti-HCV); positive participants were re-contacted to ascertain awareness of infection and to provide service referrals. Of 1,786 participants with valid anti-HCV results, 35 were positive for anti-HCV, for a weighted prevalence of 2.2% (95% confidence interval [CI] 1.5% to 3.3%). Anti-HCV prevalence was high among participants with a lifetime history of injection drug use (64.5%, 95% CI 39.2% to 83.7%) or a lifetime history of incarceration as an adult (8.4%, 95% CI 4.3% to 15.7%). There was a strong correlation with age; among participants born between 1945 and 1954, the anti-HCV prevalence was 5.8% (95% CI 3.3% to 10.0%). Of anti-HCV positive participants contacted (51%), 28% (n = 5) first learned of their HCV status from this survey. Continued efforts to prevent new infections in known risk behavior groups are essential, along with expansion of HCV screening and activities to prevent disease progression in people with chronic HCV.     

Improvement in the routine screening performance of cytotechnologists over time

BACKGROUND:

Documenting the performance of gynecologic screening in actual practice settings is difficult to achieve. In the current study, the screening performance of 11 individual cytotechnologists as well as that of the overall laboratory over 2 consecutive time periods was examined using the rapid prescreening (RPS) method.

METHODS:

RPS was performed by all cytotechnologists in a single laboratory over 2 separate 8‐month periods. The sensitivity of screening for individual and groups of cytotechnologists was examined. For purposes of comparison, cytotechnologists were divided into 2 groups: screeners with an overall routine sensitivity ≥95% and screeners with an overall sensitivity <95%.

RESULTS:

Atypical squamous cells (ASC) were used as a threshold, and routine screening sensitivity was found to vary from 68.3% to 96.8%. The overall sensitivity of the laboratory for RPS and routine screening was 43.6% and 88.4%, respectively. Over time, the overall laboratory sensitivity of routine screening improved from 85.3% to 91.3% (P = .01). During this same time frame, the sensitivity of the screeners with an overall sensitivity <95% improved from 79.3% to 91.2% (P < .001), whereas the sensitivity of screeners with an overall routine sensitivity ≥95% remained the same (96.1% to 96.4%; P = .6).

CONCLUSIONS:

In addition to improved overall performance of the laboratory by detecting and correcting errors, the results of the current study indicate that using RPS consistently over time might play a role leading to improved performance of cytotechnologists with an overall routine sensitivity <95% but not of cytotechnologists with an overall routine sensitivity ≥95%. Cancer (Cancer Cytopathol) 2009. © 2009 American Cancer Society.     

深圳地区QCT骨密度正常值调查与临床诊断标准的探讨

目的　通过对深圳地区正常人群腰椎骨密度测量 ,获得本地区QCT骨密度正常参考值。方法　采用CT扫描机 ,羟磷灰石固体体模和QCT骨密度测量软件 ,选择了无骨质疏松疾病的正常人 1 0 2 8例 ,扫描第 3、第 4腰椎中层横断面 ,做QCT骨密度测量。对测量结果进行统计处理 ,得到男女人群骨峰值和年龄组均值。通过对年龄组数据进行不同标准的统计处理 ,探讨较为合理的诊断标准。通过不同的测量方法 (单纯松质和包括皮质 )的对比 ,探讨QCT与其他方法的差异。结果　根据 2 1～ 35岁年龄段统计出的骨峰值男性第 3腰椎为 1 65 85± 30 1 7,第 4腰椎为 1 70 95± 31 81。女性第 3腰椎为 1 75 33± 2 6 95 ,第 4腰椎为 1 81 97± 2 7 63。采用 4种不同的骨峰值降低标准统计骨质疏松症检出率 ,发现M 2 5 %组检出率偏高 ,M 30 %与M 2S较接近。包括皮质骨的测量降低敏感性。结论　进行深圳地区骨密度正常值调查 ,获得了男女人群骨峰值和年龄组均值 ,临床诊断建议采用骨峰值 30 %作为QCT测量诊断骨质疏松症的基本界限     

Vascular imaging of solid tumors in rats with a radioactive arsenic-labeled antibody that binds exposed phosphatidylserine.

PURPOSE: We recently reported that anionic phospholipids, principally phosphatidylserine, become exposed on the external surface of vascular endothelial cells in tumors, probably in response to oxidative stresses present in the tumor microenvironment. In the present study, we tested the hypothesis that a chimeric monoclonal antibody that binds phosphatidylserine could be labeled with radioactive arsenic isotopes and used for molecular imaging of solid tumors in rats. EXPERIMENTAL DESIGN: Bavituximab was labeled with (74)As (beta(+), T(1/2) 17.8 days) or (77)As (beta(-), T(1/2) 1.6 days) using a novel procedure. The radionuclides of arsenic were selected because their long half-lives are consistent with the long biological half lives of antibodies in vivo and because their chemistry permits stable attachment to antibodies. The radiolabeled antibodies were tested for the ability to image subcutaneous Dunning prostate R3227-AT1 tumors in rats. RESULTS: Clear images of the tumors were obtained using planar gamma-scintigraphy and positron emission tomography. Biodistribution studies confirmed the specific localization of bavituximab to the tumors. The tumor-to-liver ratio 72 h after injection was 22 for bavituximab compared with 1.5 for an isotype-matched control chimeric antibody of irrelevant specificity. Immunohistochemical studies showed that the bavituximab was labeling the tumor vascular endothelium. CONCLUSIONS: These results show that radioarsenic-labeled bavituximab has potential as a new tool for imaging the vasculature of solid tumors.