Preoperative transarterial embolization of hypervascular vertebral tu mor with permanent particles

Objective To evaluate the safety and value of preoperative transarterial embolization of hypervascular vertebral tumors.Methods Sixteen patients with hypervascular vertebral tumors underwent transarterial embolization before surgery. The lesions were located between the middle cervical and lower lumbar spine. Forty-one arteries were embolized with permanent particles injected through a microcatheter, including polyvinyl alcohol (PVA) particles (150-500 μm) in 25 arteries and Dextran particles (150-350 μm) in 16. Of these, 31 had pieces of gelatin sponge added for proximal pedicled embolization. The criteria for judging the effectiveness of embolization were completeness of tumor removal and estimated blood loss during surgery.Results The particles were injected into the tumor feeders through superselection in 17 arteries or flow control in 24. Tumor embolization was defined as 'total' in five patients, 'nearly total' in eight, 'subtotal' in two, and 'partial' in another. There were no symptomatic complications associated with embolization. Tumors were entirely removed in all patients. The average estimated blood loss during surgery was 1510 ml (range of 200-6000 ml) for all 16 patients. Conclusion Preoperative embolization of hypervascular vertebral tumors is safe and effective. It can make complete resection of a tumor possible and can make a previously unresectable tumor resectable. Superselection or flow control is necessary to achieve effective devascularization and to avoid complications.     

胰腺囊腺瘤的多层螺旋CT诊断与鉴别诊断

目的: 探讨胰腺浆液性囊腺瘤?黏液性囊腺瘤与黏液性囊腺癌的CT表现及特征?方法: 回顾性分析26 例经手术病理证实的胰腺囊腺肿瘤患者的临床和CT检查资料,总结其CT表现?结果: 浆液性囊腺瘤13例,多为圆形或分叶状囊性或囊实性肿块影,7例见纤维分隔,5例中央可见点状钙化,门脉期囊壁及分隔强化较明显?黏液性囊腺瘤8例,呈圆形或不规则形低密度影,单囊2例,多囊6例,囊壁厚薄不均,2例囊壁及分隔可见钙化?黏液性囊腺癌5例,壁结节较大,位于胰头者1例伴胰管扩张和 CA-199增高,内见钙化者1例,胰周脂肪间隙欠清晰者2例?结论: CT能较好显示胰腺囊腺肿瘤的大小?形态,内部特征及与周围组织的关系,为临床诊断与治疗提供重要信息?     

基于机器学习方法研究造成缺血特异性狭窄的斑块特征

目的 利用机器学习（ML）方法探讨定量、定性的冠状动脉斑块特征以及血流动力学参数对缺血特异性狭窄血管的影响。 材料与方法 回顾性分析同时行冠状动脉CT血管成像（CCTA）、有创冠状动脉造影（ICA）及FFR测量的255例病人共328支血管的临床及影像资料。以FFR≤0.80作为提示病变特异性缺血的指标,依据FFR值将纳入血管分为非缺血组（FFR>0.80）和缺血组（FFR≤0.80）。测量所有纳入斑块的CCTA参数,包括斑块的定量、定性特征以及血流动力学参数。采用LogitBoost算法建立随机森林模型,通过信息增益排序方法自动选择特征。分类准确度、敏感度以及f1值（分类准确度与敏感度的调和平均值）用以评价随机森林模型对造成缺血特异性狭窄斑块的预测价值,并计算受试者操作特征（ROC）曲线下面积。采用十折分层交叉验证法计算模型的总体分类准确度。 结果 应用ML方法得出,血流动力学参数FFR_CT、ΔFFR_CT是预测缺血特异性狭窄最重要的2个特征,其次是斑块的定量、定性特征,包括脂质斑块体积、斑块弯曲、斑块不规则、非钙化斑块体积、狭窄程度、纤维斑块体积和管腔体积。在排序前10的特征中有9个是CCTA相关参数,只有1个临床参数。采用随机森林模型预测缺血特异性狭窄的分类准确度为0.940,敏感度为0.940,f1值为0.940;预测缺血特异性狭窄的 ROC曲线下面积为0.992,模型的总体分类准确度为0.921±0.047。 结论 ML方法能够很好地预测引起心肌缺血的冠状动脉特异性狭窄病变的斑块特征。