AIM: To mea sure the flowvolume of pulmonary arteries by using pha se-contra st magnetic re sonance imaging(MRI) and to inve stigate the values of pha se-contrast MRI ina sse ssing pulmonary perfusion. METHODS: Pha se-contra stMRI was performed in 20 healthy volunteers by Philips Gy-roscan NT 1. 5TMR scanner. The flow rates of main pulmonaryartery (MPA), right pulmonary artery (RPA) and left pul-monary artery (LPA) of different cardiac phases in one cardiaccycle were mea sured and the flow volumes were calculated.RESULTS: The flow volumes of MPA, RPA and LPA were (73.5

Objective To determine the value of 99m Tc-M IB I scintimmmography in diagnosing primary breast cancer and axillary lymph node metastases1Methods Independent, prospective, blinded studies were selected from the Co-chrane L ibrary, MEDL INE, Springer, Elsevier and China National Knowledge Infrastructure, Sensitivity, specificity, andaccuracy of scintimammography were estimated by comparison with the results of biop sy1 Subsequently, the characteristicsof included articles such as sensitivity, specificity of 99m Tc-M IB I scintimammorgraphy were extracted and assessed1 Differ-ent effectmodelwas chosen to calculate different pooled weighted values of sensitivity, specificity and the corresponding95% confidence intervals (95%CI). Summary receiver operating characteristic (SROC) curves was performed, then thediagnostic value was evaluated by SROC. Results The pooled ensitivity, specificity of 99m Tc-M IB I scintimammography inevaluating breastmasses, respectively were 86% (95%CI from 8-% to 89%) and 80% (95%CI from 75% to 80%). The area under the SROC (AUC) was 901-9%. For palpable breast cancer, the pooled sensitivity and specificity were86% (95%CI from 83% to 88%) and 83% (95% CI from 77% to 86%). The AUC is 94168%. For non-palpablebreast cancer, the pooled sensitivity and specificitywere 69% (95%CI from 47% to 85%) and 69% (95%CI from 5-% to8-%), respectively. The AUC was 78197%. For metastatic axillary lymph node, the pooled sensitivity and specificitywere 75% (95% CI from 66% to 81%) and 86% (95% CI from 75% to 91%) respectively. The AUC was 87164%. Conclusions 99m Tc-M IB I scintimammography has a better value in evaluating palpable breast masses when an adequatespecimen is obtained1 It has a higher specificity in evaluatingmetastatic axillary lymph node with a relativelylow sensitivi-ty. Its value for non-palpable breast cancer is limited and new methods are warranted.

ROI (region of interest) plays an important role in medical image analysis. In this paper, an efficient approach to ROI extraction based on monotonically marching curve evolution is proposed. The improvement is in two aspects: first, a new monotonically marching snake integrating ROI information is presented by minimizing the new defined ROI energy. Due to the region based speed term, the front could even propagate in low contrast and narrow thin areas. Second, a multi-initial fast marching algorithm is developed for numerical implementation, where a multi-initial scheme can perform the selective growth of the front, thus further reduce the front leaking. Furthermore, a multiscale scheme for numerical implementation is adopted, where a fast passing solution method is used for determining the initial solution on the finer scale that greatly reduces the computational cost. The validity of the proposed approach is demonstrated on the medical image ROI extraction. Experimental results show that the approach is efficient both in computational cost and segmentation quality. Low contrast and narrow thin ROI could be efficiently extracted precisely by the approach.

目的　对以肺动脉造影为金标准，研究CT肺动脉造影（CTPA）诊断肺动脉栓塞（PE）的文献进行Meta汇总分析，评价CTPA对PE的临床诊断价值。方法 检索Cochrane图书馆、PubMed，OVID数据库和中国期刊网中的英文和中文文献，按照Cochrane 协作网推荐的诊断试验的纳入标准筛选文献，并对纳入文献进行质量评估，提取纳入研究的特征信息。数据分析采用Meta-Test version019软件，检验异质性，并根据异质性结果选择相应的效应模型。对所有研究予以加权定量合并，计算灵敏度和特异度及其95%可信区间。绘制汇总受试者工作特征曲线（SROC），并计算曲线下面积。最后进行敏感性分析。结果　共纳入10篇英文文献，其中7篇为A级，3篇为B级。研究对象共计855人，CTPA诊断PE的灵敏度的范围是0157～1100，特异度的范围是0178～1100。纳入研究存在异质性。按照随机效应模型计算汇总灵敏度和特异度及95%可信区间分别为0184 （0173，0191）和0191（0187，0194）。SROC曲线下面积为94195%。纳入文献稳定性好。结论　汇总目前关于CTPA诊断PE的研究显示，CTPA是一种灵敏度和特异度较高的无创性检查方法，还需要高质量的前瞻性研究以更准确地评价其临床价值。