多层螺旋CT在肺癌临床诊断中的应用价值

目的探讨多层螺旋CT在肺癌临床诊断中的应用价值。方法对84例患者的临床病理组织学检查结果和多层螺旋CT检查结果进行对比研究,观察多层螺旋CT诊断肺癌的准确率。结果多层螺旋CT的腔内外病变、管壁增厚、转移性改变、阻塞性病灶等征象和手术病理诊断结果比较无明显差异。多层螺旋CT对肺癌的检出率与手术病理检查相比无明显差异。结论通过多层螺旋CT观察肺癌病灶诊断肺癌具有十分重要的临床价值,可提高肺癌的检出率。     

多层螺旋CT在评估慢性阻塞性肺疾病相关肺动脉高压中的应用进展

在我国慢性阻塞性肺疾病（COPD）多发生在40岁及以上人群中,而肺动脉高压（PAH）是COPD进展的中心环节,可导致右心功能衰竭乃至死亡。COPD病人出现PAH后进行早期相关治疗可显著改善预后,因此对COPD病人出现PAH的早期诊断非常重要。多层螺旋CT作为一种无创性检查,可以运用多种定量及定性指标较好地发现和提示COPD相关PAH,并可以评估预后、监测治疗效果。     

16层螺旋CT成像在原发性肺癌中的应用诊断价值分析

随着CT设备及扫描技术和相关计算机软件的不断更新发展,多层螺旋CT(multislice spiral CT,MSCT)应用于原发性肺癌的定量研究是目前的热点之一[1～5].本文探讨了多层螺旋CT成像在原发性肺癌中的应用诊断价值,提供诊断水平.     

多层螺旋CT灌注成像在不典型周围型肺癌诊断中的应用

目的评价多层螺旋CT灌注成像在不典型周围型肺癌诊断中的应用。方法回顾性分析12例不典型周围型肺癌利用多层螺旋CT灌注成像的影像表现。结果12例周围型肺癌表现不典型,主要有3种情况:a)周围型肺癌合并肺结核见于4例;b)直径小于3cm非实质性结节灶见于6例;c)单发小片状病灶见于2例。结论周围型肺癌可出现多种不典型征象,认识这些征象对临床诊断及治疗都有重要意义。     

多层螺旋CT二维(2D)及三维(MPR)在周围型肺癌的临床应用

目的　探讨多层螺旋CT二维 (2D)和多平面重建技术 (MPR)在周围型肺癌的临床应用价值。方法　 17例周围型肺癌行多层螺旋CT扫描 (层厚 1～ 2mm)和多平面重建。结果　 2D图可显示周围型肺癌内部结构、分叶征、毛刺征、病灶周围血管、胸膜、纵隔结构的关系 ,但显示的范围、征象较局限。MPR可以多个方面显示肿块与胸膜、纵隔结构关系 ,MPR可多方面清楚显示肺癌本身征象和肺癌与周围组织的关系。结论　以 2D螺旋CT图为基础 ,结合MPR对诊断周围型肺癌有重要的临床应用价值     

多层螺旋CT与X线检查在肺癌临床诊断中的应用

目的探讨多层螺旋CT与X线检查在肺癌诊断中的效果。方法肺癌患者56例作为研究对象,对所有患者在病理确诊前均行多层螺旋CT和胸部X线检查,将两种检查方法诊断结果分别与临床病理组织学检查结果进行对比研究,比较多层螺旋CT和胸部X线诊断肺癌的的敏感度、特异度和准确性。结果 56例患者经病理学检查确诊为肺癌(阳性)38例,其中中央型肺癌20例,周围型肺癌18例;阴性18例,其中肺结核6例,肺部感染4例,肺部纤维瘤4例,纵膈恶性淋巴瘤4例。以手术病理诊断结果为金标准,螺旋CT检查诊断肺癌的敏感度、特异度和准确性分别为94.74%,77.78%,89.29%。结论多层螺旋CT观察肺癌病灶诊断肺癌具有十分重要的临床价值,X线平片可先作为早期筛查首选影像学检查方法。     

多层螺旋CT低剂量扫描在早期肺癌筛查中的应用价值分析

肺癌是临床上较为常见的恶性肿瘤类型,其发病率、死亡率均处于较高水平,且随着环境污染的加重,人们不良生活方式的增多,导致该病的患病人数逐年增长,不仅危及患者的生命安全,降低其生活质量,同时给家庭、社会造成一定的负担[1]。相关报道指出,长时间的吸烟患者发生肺癌的概率是不吸烟者的20~30倍,且吸烟年龄越小,其后期发生肺癌的风险性越高;此外,吸烟不仅对自身的身体造成不利的影响,还可影响周围人群的身体健康,使其产生被动吸烟,提高肺癌的患病率,若可准确有效的将患者在疾病发病初期检出,并实施合理化的治疗,可有效提升疾病的治疗效果及预后情况[2]。X线胸片、螺旋CT检查是肺癌常用的检查方式,目前临床上为降低X线照射量,确保影像质量符合影像与临床诊断的标准,实施低剂量多层螺旋CT扫描其效果较为理想。基于此,本研究探讨了在早期肺癌筛查中采用多层螺旋CT低剂量扫描的效果。     

多层螺旋CT二维(2D)及三维(SSD)在周围型肺癌的临床应用

目的　探讨多层螺旋CT二维 (2D)和表面覆盖技术 (SSD)在周围型肺癌的临床应用价值。方法　 3 5例周围型肺癌行多层螺旋CT扫描 (层厚 1～ 2mm)和表面覆盖技术。结果　 2D图可显示周围型肺癌内部结构、分叶征、毛刺征、病灶周围血管、胸膜、纵隔结构的关系 ,但不能立体、直观显示肿瘤与周围器官的关系。SSD可多方向立体、直观清楚显示肿瘤表面征象和肿瘤与周围组织的关系。结论　以 2D螺旋CT图为基础 ,结合SSD对诊断周围型肺癌有重要的临床应用价值。     

多层螺旋CT小肝癌和小血管瘤扫描技术探讨

CT机单层螺旋CT发展到今天、多层螺旋CT(64层螺旋CT)。多层螺旋CT具有优良密度辨率和空间分辨率,受检者受线量少。多层螺旋CT已广泛应用于肝脏疾病检查。如何正确地运用多层螺旋CT扫描技术,对小肝癌、小血管瘤的检出率、鉴别诊断具有重要意义。     

螺旋CT诊断周围型小肺癌的价值

肺癌是目前最常见的恶性肿瘤之一,而且有不断上升之趋势.周围型小肺癌是指起源于肺段以下支气管,直径小于3cm的恶性结节[1],其临床症状出现较晚,确诊时多属中晚期,已失去根治机会,因此,早期诊断至关重要.CT特别是螺旋CT扫描在周围型小肺癌诊断中起着重要作用.本研究收集我院近3年来经手术病理证实的24例周围型小肺癌病例,对其CT表现进行分析、总结,以探讨螺旋CT对其诊断价值.     

Theoretical basis for long-term measurements of equilibrium factors using LR 115 detectors

In this paper, we propose a method to determine the equilibrium factor using a bare LR 115 detector. The partial sensitivities ρ_i of the LR 115 detector to ²²²Rn and its alpha-emitting short-lived progeny, ²¹⁸Po and ²¹⁴Po, were investigated. We first determined the distributions of lengths of major and minor axes of the perforated alpha tracks in the LR 115 detector produced by ²²²Rn, ²¹⁸Po and ²¹⁴Po through Monte Carlo simulations. The track parameters were calculated using a track development model with a published V function, by assuming a removed active layer of 6.54 μm. The distributions determined for different alpha emitters were found to completely overlap with one another. This implied equality of partial sensitivities for radon and its progeny, which was also confirmed through analytical considerations. Equality of partial sensitivities makes possible convenient measurements of the proxy equilibrium factor F_p, which is defined in the present work as (F₁+F₃) and is equal to the ratio between the sum of concentrations of the two alpha emitting radon progeny (²¹⁸Po+²¹⁴Po) to the concentration of radon gas (²²²Rn). In particular, we have found F_p=(ρ/ρ_itC₀)−1, where ρ (track/m²) is the total track density on the detector, ρ_i=0.288×10⁻² m, t is the exposure time and C₀ (Bq/m³) is the concentration of ²²²Rn. If C₀ is known (e.g. from a separate measurement), we can obtain F_p. The proxy equilibrium factor F_p is also found to be well correlated with the equilibrium factor between radon gas and its progeny through the Jacobi room model. This leads to a novel method for long-term determination of the equilibrium factor.     

Influence of a TcN core on the biological and physicochemical behavior of Tc complexes of L,L-EC and L,L-ECD

^99mTc-nitrido complexes of L,L-ethylene dicysteine (^99mTcN-L,L-EC) and ^99mTcN-L,L-ethylene dicysteine diethylester (^99mTcN-L,L-ECD) were prepared and their characteristics compared to those of the respective ^99mTc-oxo complexes. ^99mTcN-L,L-EC and ^99mTcO-L,L-EC migrate to similar extents during electrophoresis at pH 12, but, at pH 6, ^99mTcN-L,L-EC migrates further than ^99mTcO-L,L-EC. Renal excretion of ^99mTcN-L,L-EC is inferior to that of ^99mTcO-L,L-EC, indicating that the TcN-glycine sequence has lower affinity for the renal tubular system. Both ^99mTcO-L,L-ECD and ^99mTcN-L,L-ECD are neutral, but ^99mTcN-L,L-ECD is hydrophilic and shows minimal brain uptake in both mice and the baboon.     

Effects of increased ventilation and improved pulmonary gas-exchange on maximal oxygen uptake and power output

Recent reports suggest that aerobic performance at very high levels may be limited by the pulmonary system. The purpose of the present study was to compare respiratory functions at rest and during graded maximal aerobic exercise (cycle ergometry) between well-trained (TR, n = 11) and untrained (UT, n = 14) individuals while breathing atmospheric air, normoxic helium (He) and oxygen-enriched mixture. When the subjects breathed air, TR exhibited lower exercise ventilatory reserve (MVV-VE_max), ratio between minute ventilation (VE) and oxygen uptake (V_o2) and SaO₂ than UT. Breathing HE resulted in an increase in VE and V_o2max in both groups but in an increased VE/V_o2 and SaO₂ and maximal mechanical cycle ergometer load, only in TR. Compared with air, breathing an oxygen-enriched mixture resulted in increased peak exercise SaO₂ and maximal mechanical load in both groups. It is concluded that arterial O₂ desaturation secondary to a relative hypoventilatory response may limit V_o2max and aerobic performance capacity at high work levels.     

Assessment of the skeletal status by MR relaxometry techniques of the lumbar spine: comparison with dual X-ray absorptiometry

Purpose: To measure lumbar spine T2*, T2, T2′ and T1 MR relaxometry parameters and compare them with lumbar spine bone mineral density (BMD) in a group of postmenopausal women. Materials and methods: Lumbar spine T2*, T2, T2′ and T1 MR relaxometry parameters and BMD values were assessed in 101 postmenopausal women (mean age: 61.8±7.1 (1 S.D.) years); of them 63 referred to as control subjects (group A, BMD T-scores ≥ −2.5 S.D.) and 38 as osteoporotic (group B, BMD T-scores < −2.5 S.D.). All magnetic resonance imaging (MRI) examinations were performed on an 1.5 T imaging system using: (a) a 2D single slice multi echo (32 echoes) gradient echo (MEGRE) sequence (TR/TE1/TE32/FA: 160/2.7/74.93 ms/25°) for the T2* measurement, (b) a respiratory gated 2D single slice Multi Echo (16 echoes) Spin Echo (MESE) sequence (TR/TE1/TE16/FA: 2000–2500/22.5/360 ms/90°) for the T2 measurement and (c) a 2D single slice multi TI (18 repeats) turbo Fast Low Angle Shot (turbo FLASH) sequence (TR/TE/TI1/TI16/FA: 11/4.2/10/5000 ms/10°) for the T1 measurement. T2′ was calculated from its definition equation: (1/T2′ = 1/T2* − 1/T2). Lumbar spine BMD was assessed using DXA. Results: All measured parameters showed statistically significant differences between groups A and B (from P<0.05 to <0.001). All parameters showed significant associations with subject’s age ranging from r=0.245 (P<0.05) for the T2 up to r=0.377 (P<0.001) for the T2*. All parameters showed significant associations with subject’s BMD measurements ranging from r=−0.184 (P<0.05) for the R1 = (1/T1) up to r=−0.345 (P<0.0005) for the T2. Conclusion: Among the MR relaxometry parameters studied, T2* and T2 showed better discrimination of patients with osteoporosis from control subjects.     

Maximal oxygen uptake as a predictor of performance ability in women and men elite cross-country skiers

Maximal oxygen uptake (O_2max) was measured in 51 females and males classified as either world-class, medium-class or less successful elite skiers. The O_2max in the male world-class skiers was significantly higher (mean 85.6 ml·kg⁻¹·min⁻¹ or 355 ml·min⁻¹ kg⁻²³) than in the other elite skiers. World-class and medium-class female skiers had identical mean O_2max expressed in ml·kg⁻¹·min⁻¹ (70.7 and 70.6, respectively), but the values differed significantly when the unit ml·min⁻¹kg^−2/3 was used (274 and 264, respectively). O_2max expressed as ml·min⁻¹·kg^−2/3 reflects differences in performance capability among elite skiers better than the unit ml·kg⁻¹·min⁻¹.     

A comparative study of 188Re(V)-meso-DMSA and 188Re(V)-rac-DMSA: preparation and in vivo evaluation in nude mice xenografted with a neuroendocrine tumor

Dimercaptosuccinic acid (DMSA) exists in meso and racemic (rac) forms. Unlike a meso isomer, rac-2,3-DMSA is very soluble in water, strongly acidic solutions and organic solvents. Despite these differences, rac-2,3-DMSA has not been studied as a radiopharmaceutical. In this study, ¹⁸⁸Re complexes with diastereomeric DMSA were prepared to compare the properties of ¹⁸⁸Re(V)-rac-DMSA with those of ¹⁸⁸Re(V)-meso-DMSA in in vitro and in vivo models.

Methods

rac-2,3-DMSA was synthesized and radiolabeled with ¹⁸⁸Re. The biodistribution and gamma camera imaging of ¹⁸⁸Re(V)-meso-DMSA and ¹⁸⁸Re(V)-rac-DMSA were performed in nude mice subcutaneously implanted with PC-12 cell lines.

Results and conclusions

Both ¹⁸⁸Re(V)-meso-DMSA and ¹⁸⁸Re(V)-rac-DMSA showed excellent radiochemical purity and stability at room temperature. Compared with ¹⁸⁸Re(V)-meso-DMSA, ¹⁸⁸Re(V)-rac-DMSA needed a higher concentration of rac-DMSA and metabisulfite for maximum yields. ¹⁸⁸Re(V)-meso-DMSA showed high labeling efficiency at pH 2, whereas ¹⁸⁸Re(V)-rac-DMSA showed maximum yields at pH 5. The tumor uptake of ¹⁸⁸Re(V)-rac-DMSA was 3.5 times higher than that of ¹⁸⁸Re(V)-meso-DMSA at 1 h (P<.01). Gamma camera images showed that ¹⁸⁸Re(V)-rac-DMSA was more selectively localized than ¹⁸⁸Re(V)-meso-DMSA at the tumor region in a xenograft model. These results demonstrate that ¹⁸⁸Re(V)-rac-DMSA may have better potential than ¹⁸⁸Re(V)-meso-DMSA as a therapeutic agent against neuroendocrine tumors.