肝内胆管上皮癌的局部治疗:定量容积ADC图对肿瘤疗效的评估

摘要目的探讨通过分析容积表观扩散系数(ADC)的变化和MR肝动脉期、门静脉期增强成像对比剂强化区域容积变化的方法评价经导管动脉化疗栓塞术(TACE)对胆管细胞癌早期疗效的可行性。材料与方法共29例不能手术切除的胆管细胞癌病人入组,包括11例男性[平均年龄(60±16.8)岁]和18例女性[平均年龄(63±11.5)岁],本研究为回顾性研究,得到伦理委员会同意并符合HIPAA标准,不需要病人签署知情同意书。在研究期间共进行69次TACE手术(1～5次TACE手术)。所有病人均没有接受TACE以外的其他治疗。     

肝脏肿瘤和正常肝组织CT灌注参数的可重复性研究

目的评估肝脏肿瘤和正常肝组织CT灌注的可重复性,以及呼吸运动和数据采集时间对参数可重复性的影响。材料与方法本前瞻性研究获得伦理委员会批准和受试者知情同意。本研究符合HIPAA要求。7例有肝脏肿瘤的病人间隔2～7d分别进行两次CT灌注扫描,每次检查有2个     

以CT阈值(HU)诊断肾脏血管平滑肌脂肪瘤:感兴趣区大小与肾实质期成像的影响

目的回顾性研究诊断肾脏血管平滑肌脂肪瘤(AML)以及与肾细胞癌(RCC)鉴别诊断时所需要的最佳CT阈值(HU)与兴趣区(ROI)的大小。材料与方法本研究经机构审查委员会批准并符合HIPAA,病人均签署知情同意书。     

胶质瘤:标准或高b值扩散加权MR成像表观扩散系数图的直方图分析——与肿瘤级别的相关性

目的基于整个肿瘤容积数据获得表观扩散系数(ADC)图的直方图,探索其在分析确定胶质瘤级别中的作用,评价标准b值(1000s/mm2)和高b值(3000s/mm2)ADC图的诊断性能。材料与方法此回顾性研究经机构审查委员会批准,无需知情同意。27例星形细胞瘤病人进行了b值为     

良性肝细胞病变的高b值扩散加权MR成像:定性与定量分析

目的分析良性肝细胞病变在高b值扩散加权MR成像中的信号强度(SI),并比较局灶性结节增生(FNH)与肝细胞腺瘤(HCA)的表观扩散系数(ADC)。材料与方法本回顾性研究获机构审查委员会批准,免除知情同意。入选标准为诊断FNH或HCA的连续病人,接受3种b值(0、150、     

肝小血管瘤与小肝癌的鉴别诊断:最新介绍的能谱CT的方法

目的研究动脉晚期和门静脉期,CT能谱成像参数在鉴别伴或不伴肝硬化的肝小血管瘤与小肝癌(≤3cm)中的应用价值。材料与方法这项前瞻性的研究得到了伦理委员会的批准,并且所有病人签署了知情同意书。49例病人(39例男性病人,10例女性病人;65个病灶部位)接受了动     

可手术的非小细胞肺癌:动态增强螺旋CT容积扫描与肿瘤缺氧免疫组化指标对照研究

摘要目的分析非小细胞肺癌(non-small cell lung cancer,NSCLC)检查中动态对比增强(dynamic contrast material-enhanced,DCE)螺旋CT结果与肿瘤缺氧免疫组化指标的关系。材料与方法本研究经过伦理委员会许可,20例临床怀疑NSCLC病人于术前24h接受全肿瘤DCECT扫描并行动力学建模(Patlak分析)。根据扫描数据,推算出胸腔引流量[mL/(100mL·min)]及血容量(mL/100mL)。     

利用CT血管成像对肾脏进行测量:与活体肾移植供者肾功能的相关性研究

摘要目的探讨CT血管成像(CTA)影像上测量供体肾脏大小的哪个参数与肾移植术前和术后的肾功能关系最密切。材料与方法伦理审查委员会批准了此项符合HIPAA的回顾性研究,且无需获得病人知情同意。在CTA影像上对111例进行活体肾移植术肾脏的长度、     

MRI和FDG PET/CT对鼻咽癌化疗和放疗后肿瘤残留和(或)复发的检出及“再分期”价值的比较

目的比较MRI和18F-FDGPET/CT单独或联合使用对治疗后的鼻咽癌残留或复发的检出及再分期价值。材料与方法本次回顾性研究得到当地医学伦理委员会批准,     

小的(≤20mm)胰腺腺癌:多期相多层螺旋CT增强方式和间接征象分析

目的评价在多期相多层螺旋CT影像上直径≤20mm胰腺癌的增强方式、间接征象出现率及组织病理学特性。材料与方法本回顾性研究被审查委员会所认可,不需签署知情同意书。作者回顾了2002年1月—2009年9月共163例连续病人的临床和影像学数据,其中130例病人(男     

Dynamic contrast-enhanced MRI in the differentiation of breast tumors: user-defined versus semi-automated region-of-interest analysis

Dynamic contrast-enhanced MR mammography is an increasingly used method of evaluating breast pathology. The purpose of this study was to compare two semi-automated methods of region of interest (ROI) analysis with a user-defined method, in the discrimination of breast tumors using dynamic contrast-enhanced MRI. Results are presented from the retrospective analysis of 81 malignant and 36 benign breast lesions. The study demonstrates the importance of a consistent ROI strategy and also shows that semi-automated approaches offer a standardized method, which may improve the discrimination of primary breast tumors. J. Magn. Reson. Imaging 1999; 10:945-949.     

Coronary artery calcium quantification at multi-detector row helical CT versus electron-beam CT

PURPOSE: To compare coronary artery calcium scores from a multi-detector row helical computed tomographic (CT) scanner with those from an electron-beam CT scanner, with emphasis on subjects with calcium scores less than 400. MATERIALS AND METHODS: Seventy-eight asymptomatic subjects (37 women, 41 men; age range, 39-78 years; mean age, 54.2 years) underwent multi-detector row CT and electron-beam CT. Volume and Agatston scores were calculated with a workstation. Statistical analyses included assessment of association between calcium scores from two scanners, calculation of percent absolute difference to assess score variability between scanners, equivalence analysis, construction of Bland-Altman plots to assess agreement between scores, and assessment of changes in score grouping and risk criteria based on score differences between scanners. RESULTS: Electron-beam CT calcium scores were higher than multi-detector row CT scores. Linear association between calcium scores obtained from paired scans was significant (r = 0.96-0.99, P <.001). Mean percent absolute differences were 67.9% and 65.0% for volume and Agatston scores, respectively (48.6% and 46.3% for corresponding natural log-transformed scores). In subjects with a score of 11 or greater, mean percent absolute differences between electron-beam CT and multi-detector row CT scores ranged from 15% to 30% (<10% for natural log-transformed calcium scores). With a 20% equivalence limit, calcium scores from the two scanners were statistically equivalent (P <.05). Score grouping would have been subject to change in 12 (11 increased and one decreased; six with scores of 11 or greater), and possible risk management decisions would have been subject to change in eight (16%) of 51 subjects who underwent electron-beam CT versus multi-detector row CT scanning. CONCLUSION: Multi-detector row CT appears to be comparable to electron-beam CT for coronary calcification screening, except in subjects with a calcium score less than 11.     

Precision and accuracy in CT attenuation measurement of vascular wall using region-of-interest supported by differentiation curve

Objectives

To evaluate the precision and accuracy in CT attenuation measurement of vascular wall using region-of-interest (ROI) supported by differentiation curves.

Study design

We used vascular models (actual attenuation value of the wall: 87 HU) with wall thicknesses of 1.5, 1.0, or 0.5 mm, filled with contrast material of 250, 348, or 436 HU. The nine vascular models were scanned with a 64-detector CT. The wall attenuation values were measured using three sizes (diameter: 0.5, 1.0, and 1.5 mm) of ROIs without differentiation curves. Sixteen measurements were repeated for each vascular model by each of two operators. Measurements supported by differentiation curves were also performed. We used analyses of variance with repeated measures for the measured attenuations for each size of the ROI.

Results

Without differentiation curves, there were significant differences in the attenuation values of the wall among the three densities of contrast material, and the attenuation values tended to be overestimated more as the contrast material density increased. Operator dependencies were also found in measurements for 0.5- and 1.5-mm thickness models. With differentiation curves, measurements were not possible for 0.5- and 1.0-mm thickness models. Using differentiation curves for 1.5-mm thickness models with a ROI of 1.0- or 1.5-mm diameter, the wall attenuations were not affected by the contrast material densities and were operator independent, measuring between 75 and 103 HU.

Conclusions

The use of differentiation curves can improve the precision and accuracy in wall attenuation measurement using a ROI technique, while measurements for walls of ≤1.0 mm thickness are difficult.     

CT attenuation correction for myocardial perfusion quantification using a PET/CT hybrid scanner.

In routine PET, a 10- to 20-min transmission scan with a rotating (68)Ge source is commonly obtained for attenuation correction (AC). AC is time-consuming using this procedure and could considerably be shortened by instead using a rapid CT scan. Our aim was to evaluate the feasibility of CT AC in quantitative myocardial perfusion PET using a hybrid PET/CT scanner. METHODS: (13)N-labeled NH(3) and PET were used to measure myocardial blood flow (MBF) (mL/min/g) at rest and during standard adenosine stress. In group 1 (n = 7), CT scans (0.5 s) of the heart area with different tube currents (10, 40, 80, and 120 mA) were compared with a standard (68)Ge transmission (20 min) and with no AC. In group 2 (n = 3), the repeatability of 8 consecutive CT scans at a tube current of 10 mA was assessed. In group 3 (n = 4), emission was preceded and followed by 3 CT scans (10 mA) and 1 (68)Ge scan for each patient. For reconstruction, filtered backprojection (FBP) was compared with iterative reconstruction (IT). RESULTS: For group 1, no significant difference in mean MBF for resting and hyperemic scans was found when emission reconstructed with (68)Ge AC was compared with emission reconstructed with CT AC at any of the different tube currents. Only emission without any correction differed significantly from (68)Ge AC. For group 2, repeated measurements revealed a coefficient of variance ranging from 2% to 5% and from 2% to 6% at rest and at stress, respectively. For group 3, similar reproducibility coefficients (RC) for MBF were obtained when (68)Ge AC(FBP) was compared with (68)Ge AC(IT) (RC = 0.218) and when CT AC(FBP) was compared with CT AC(IT) (RC = 0.227). Even better reproducibility (lower RC) was found when (68)Ge AC(FBP) was compared with CT AC(FBP) (RC = 0.130) and when (68)Ge AC(IT) was compared with CT AC(IT) (RC = 0.146). CONCLUSION: Our study shows that for the assessment of qualitative and quantitative MBF with a hybrid PET/CT scanner, the use of CT AC (with a tube current of 10 mA) instead of (68)Ge AC provides accurate results.     

Polyps: linear and volumetric measurement at CT colonography

PURPOSE: To retrospectively determine which of several computed tomographic (CT) colonography-based polyp measurements is most compatible with the linear measurement at optical colonoscopy and which is best for assessing change in polyp size. MATERIALS AND METHODS: This HIPAA-compliant study had institutional review board approval; informed consent was obtained. Prone and supine CT colonography with same-day optical colonoscopy was performed in 216 patients (147 men and 69 women; age range, 46-79 years; mean age, 59.2 years) with 338 polyps detected at CT colonography. Polyp size was measured with three linear measurements and two volume measurements. One linear measurement and one volume measurement were performed by using automated segmentation; remaining measurements were performed manually. Compatibility with linear size at optical colonoscopy and measurement reproducibility were assessed three ways: variation from size measurement at optical colonoscopy, change between prone and supine scans, and variability between observers. Confidence analysis assessed the ability of each measurement to identify polyps with an optical colonoscopy measurement of 1 cm or greater. RESULTS: Two hundred fifty-one segmentable polyps were present on both supine and prone scans. Linear polyp diameter manually measured on a three-dimensional endoluminally viewed surface (L(M3D)) indicated with 95% confidence that a polyp measured as 0.8 cm or smaller was less than 1.0 cm at optical colonoscopy. Prone and supine polyp size difference was smallest for L(M3D) and the linear diameter computed from manual and automated volume measurements, with interquartile ranges smaller than or equal to 0.3, 0.2, and 0.5 cm, respectively. Interobserver and intraobserver variability was smallest for linear polyp diameter measurements on a two-dimensional display, with a mean percentage difference of 2.8% (95% Bland-Altman limits of agreement: -17.8%, 23.4%) and 5.0% (95% Bland-Altman limits of agreement: -28.3%, 38.3%), respectively. CONCLUSION: L(M3D) best approximated polyp size measurements at optical colonoscopy. Linear diameter calculated from automated volume measurements showed the smallest variation between supine and prone scans while avoiding observer variability and may be best for assessing polyp size changes with serial examinations.     

A technique for using CT images in attenuation correction and quantification in SPECT

A technique is described for using computed tomography (CT) images for attenuation correction and quantification in SPECT. The CT images are aligned with the corresponding SPECT slices and the Hounsfield units are converted to linear attenuation coefficient values for the SPECT radionuclide. The attenuation coefficient map thus produced is used to provide the attenuation correction required in the SPECT reconstruction. The technique has been evaluated in both a non-anatomical and an anatomical phantom giving a mean accuracy in quantifying activity of various features in the phantoms of 2.6% (range 0.3%-4.0%). The value of performing scatter correction prior to attenuation correction in obtaining accurate quantification is demonstrated. The practicalities of applying the technique in patient studies are discussed.     

Sixteen-slice CT with volumetric analysis of foot fractures

Computed tomography (CT) imaging of the foot demands excellent resolution for the delineation of complex fractures and joint alignment after trauma. The quality of current multislice volumetric acquisition results in exceptional multiplanar and 3-D reconstructions, precluding the requirement for an additional acquisition in a second plane. This pictoral essay depicts fractures of various bones of the foot, with reference to recent investigative studies demonstrating the value of CT in the evaluation of foot fractures.