Diagnostic Performance of CT Angiography in Patients Visiting Emergency Department with Overt Gastrointestinal Bleeding

Objective

To investigate the diagnostic performance of computed tomography angiography (CTA) in identifying the cause of bleeding and to determine the clinical features associated with a positive test result of CTA in patients visiting emergency department with overt gastrointestinal (GI) bleeding.

Materials and Methods

We included 111 consecutive patients (61 men and 50 women; mean age: 63.4 years; range: 28-89 years) who visited emergency department with overt GI bleeding. They underwent CTA as a first-line diagnostic modality from July through December 2010. Two radiologists retrospectively reviewed the CTA images and determined the presence of any definite or potential bleeding focus by consensus. An independent assessor determined the cause of bleeding based on other diagnostic studies and/or clinical follow-up. The diagnostic performance of CTA and clinical characteristics associated with positive CTA results were analyzed.

Results

To identify a definite or potential bleeding focus, the diagnostic yield of CTA was 61.3% (68 of 111). The overall sensitivity, specificity, positive predictive value (PPV), and negative predictive value were 84.8% (67 of 79), 96.9% (31 of 32), 98.5% (67 of 68), and 72.1% (31 of 43), respectively. Positive CTA results were associated with the presence of massive bleeding (p = 0.001, odds ratio: 11.506).

Conclusion

Computed tomography angiography as a first-line diagnostic modality in patients presenting with overt GI bleeding showed a fairly high accuracy. It could identify definite or potential bleeding focus with a moderate diagnostic yield and a high PPV. CTA is particularly useful in patients with massive bleeding.     

肾上腺节细胞神经瘤的多层螺旋CT诊断与临床分析

目的对肾上腺节细胞神经瘤的多层螺旋CT(MSCT)诊断与临床特征进行分析。方法对我院2010—2012年收治的60例肾上腺无功能性肿瘤患者进行回顾性分析。其中肾上腺节细胞神经瘤患者18例,肾上腺无功能腺瘤患者24例,转移瘤8例,无功能嗜铬细胞瘤患者10例,共64个病灶。采用Lightspeed VCT 64层螺旋CT扫描仪对其病灶行平扫及随后30 s、70 s、3 min动态增强扫描,并将其影像学表现进行比较分析。结果①肾上腺节细胞瘤形态上大多表现为卵圆形,边界模糊,密度均匀,有明显的桃尖征,病变部位多以右侧为主,可又钙化的情况出现;②肾上腺节细胞神经瘤在同一扫描或时间点的CT平均值与其他各病变类型差异均有统计学意义(P<0.05),其中平扫时表现出密度高于无功能腺瘤,而低于嗜铬细胞瘤和转移瘤,而在增强扫描各时间点其密度则表现出明显低于其他各病变类型,差异均具有统计学意义(P<0.05)。结论临床上肾上腺节细胞神经瘤与其他各类型肾上腺无功能肿瘤相比,其MSCT表现在其病变形态、边界清晰度、肿瘤内钙化、发病部位与平扫CT平均值及增强扫描各时间点CT平均值均有明显的差异性,临床可根据其特点进行鉴别诊断,并对其手术治疗提供影像学依据。     

T2-Weighted Liver MRI Using the MultiVane Technique at 3T: Comparison with Conventional T2-Weighted MRI

Objective

To assess the value of applying MultiVane to liver T2-weighted imaging (T2WI) compared with conventional T2WIs with emphasis on detection of focal liver lesions.

Materials and Methods

Seventy-eight patients (43 men and 35 women) with 86 hepatic lesions and 20 pancreatico-biliary diseases underwent MRI including T2WIs acquired using breath-hold (BH), respiratory-triggered (RT), and MultiVane technique at 3T. Two reviewers evaluated each T2WI with respect to artefacts, organ sharpness, and conspicuity of intrahepatic vessels, hilar duct, and main lesion using five-point scales, and made pairwise comparisons between T2WI sequences for these categories. Diagnostic accuracy (Az) and sensitivity for hepatic lesion detection were evaluated using alternative free-response receiver operating characteristic analysis.

Results

MultiVane T2WI was significantly better than BH-T2WI or RT-T2WI for organ sharpness and conspicuity of intrahepatic vessels and main lesion in both separate reviews and pairwise comparisons (p < 0.001). With regard to motion artefacts, MultiVane T2WI or BH-T2WI was better than RT-T2WI (p < 0.001). Conspicuity of hilar duct was better with BH-T2WI than with MultiVane T2WI (p = 0.030) or RT-T2WI (p < 0.001). For detection of 86 hepatic lesions, sensitivity (mean, 97.7%) of MultiVane T2WI was significantly higher than that of BH-T2WI (mean, 89.5%) (p = 0.008) or RT-T2WI (mean, 84.9%) (p = 0.001).

Conclusion

Applying the MultiVane technique to T2WI of the liver is a promising approach to improving image quality that results in increased detection of focal liver lesions compared with conventional T2WI.     

Evaluation of Arterial Impairment after Experimental Gelatin Sponge Embolization in a Rabbit Renal Model

ObjectiveArterial stenosis is a major obstacle for subsequent interventional procedures. We hypothesized that the stenosis is caused by gelatin sponge embolization and performed an experimental study in a rabbit renal model.ResultsGelatin sponge particles were mainly observed in the segmental and interlobar arteries. Transmural inflammation of the embolized arterial wall and mild thickening of the media were observed 1 week after embolization. Resorption of the gelatin sponge and organization of thrombus accompanied by foreign body reactions, were observed from 2 to 4 weeks after embolization. Microscopic images of the 3 weeks group showed vessel lumens filled mostly with organized thrombi, resulting in severe stenosis. Additionally, vessels showed a thickened intima that contained migrating smooth muscle cells and accompanying interruption of the internal elastic lamina. The migrating smooth muscle cells were distributed around the recanalized arterial lumen.ConclusionGelatin sponge embolization may induce arterial stenosis by causing organized thrombus and intimal hyperplasia, which consists of migrating smooth muscle cells and intimal collagen deposits.     

Stent Compression in Iliac Vein Compression Syndrome Associated with Acute Ilio-Femoral Deep Vein Thrombosis

ObjectiveThis study was conducted to evaluate stent compression in iliac vein compression syndrome (IVCS) and to identify its association with stent patency.ResultsAll of the stents used were laser-cut nitinol stents. The proportion of limbs showing significant stent compression was 33%. Fifty-six percent of limbs in the significant stent compression group developed stent occlusion. On the other hand, only 9% of limbs in the insignificant stent compression group developed stent occlusion. Significant stent compression was inversely correlated with stent patency (p < 0.001). The median patency period evaluated with Kaplan-Meier analysis was 20.0 months for patients with significant stent compression. Other factors including gender, age, and type of stent were not correlated with stent patency. Significant stent compression occurred most frequently (87.5%) at the upper end of the stent (ilio-caval junction).ConclusionSignificant compression of nitinol stents placed in IVCS highly affects stent patency. Therefore, in order to prevent stent compression in IVCS, nitinol stents with higher radial resistive force may be required.     

诱导加同步时辰化疗联合调强放射治疗鼻咽癌的前瞻性随机对照研究

目的 分析诱导化疗加同步时辰化疗与同步常规化疗联合调强放疗治疗局部晚期鼻咽癌的不良反应、淋巴免疫功能及疗效.方法 将60例局部晚期鼻咽癌患者采用信封法随机分组,试验组为诱导化疗加同步时辰化疗联合调强放疗,对照组为诱导化疗加同步常规化疗联合调强放疗.两组均采用2个周期多西他赛+顺铂+5-氟尿嘧啶诱导化疗,同步化疗均采用顺铂,试验组采用时辰给药方式,对照组采用常规静脉给药方式.观察两组的不良反应、淋巴免疫功能及疗效.结果 同步放化疗期间试验组恶心(Z=2.50,P＜0.05)、呕吐(Z=3.31,P＜0.05)较对照组轻.同步放化疗后试验组CD4 +/CD8+高于对照组(t=3.34,P＜0.05).两组诱导化疗加同步放化疗的疗效差异无统计学意义(P＞0.05).结论 在不降低疗效的情况下,时辰给药方式能减轻恶心、呕吐不良反应,改善免疫功能,有可能成为鼻咽癌一种更合理的治疗方式.     

Novel SLA-DQ alleles and their recombinant molecules in xenogeneic stimulation of human T cells

MHC class II antigens DR and DQ are essential for graft rejection both in allo- and xeno-transplantation. The antigens, especially the DQA and DQB gene-coencoded DQ molecules, are also involved in transplantation tolerance induced by activation of regulatory T cells. Here we report six novel DQ alleles from three properly inbred Chinese pig strains Gz, Bm and Yn. In our study, cDNA of swine leukocyte antigen (SLA)-DQA and -DQB were amplified by RT-PCR and sequenced for each strain. The ORF-containing SLA-DQA and -DQB genes are composed of 768 (or 765) and 786 nucleotides, encoding antigen molecules of 255 (or 254) and 261 amino acid residues, respectively. Sequences of both SLA-DQA and -DQB alleles showed disparities when compared either among the three pig strains or with available SLA data, which allows our novel alleles receiving their accession numbers from GenBank. The sequence analysis further revealed a phylogenic connection of our SLA-DQ alleles with SLA-DQ(c) haplotype. In addition, the homologies of MHC DQ or DQ-like molecules between Chinese pigs (SLA) and human (HLA) are higher than those between pigs and mice (H-2). By co-transfection of Bm pig DQA and DQB genes into L929 cells, the Bm-DQ heterodimer-expressed cells could effectively stimulate the human lymphoproliferation in presence of human APCs with a mean stimulation index (SI) 9.9+/-1.4. This functional assay indicated that our recombinant DQ antigens are capable of initiating human lymphoproliferation in a xeno-MLR.