Tracheal cross-sectional area in children: CT determination

A computer method that calculates tracheal cross-sectional area by compensating for partial volume averaging was developed and validated in a study with phantoms. The program was then used to determine the tracheal cross-sectional area of 30 normal children who ranged in age from four months to 18 years. CT-derived cross sections were correlated with age, height, weight, and body-surface area, and they were compared with findings of published clinical and post-mortem studies. CT cross-sectional areas ranged from 20-275 mm2, varied by as much as 22% at the three different tracheal levels studied, and appeared to correlate most closely with body height. CT-derived tracheal cross-sectional areas are quite similar to those in published reports of postmortem and clinical studies. Measurement of tracheal cross section by CT may prove useful in quantitating tracheal compromise by intrinsic or extrinsic causes.     

Pulmonary vein varix: diagnosis with multi-slice helical CT

The diagnosis of a pulmonary vein varix with a recently introduced new CT technology, multi-slice helical CT, is discussed. The advantage of multi-slice helical CT lies in increased thin-slice coverage during a single breath hold, which is the predominant factor limiting scan time. This CT technique facilitates the diagnosis of vascular pulmonary pathology. Received: 6 September 1999; Revised: 16 December 1999; Accepted: 15 February 2000     

Correlation of carotid stenosis diameter and cross-sectional areas with CT angiography

PURPOSE: Carotid stenosis quantification traditionally uses measurements of narrowest stenosis diameter. The stenotic carotid lumen, however, is often irregularly shaped. New PACS workstation tools allow for more precise calculation of carotid geometry. We compare the narrowest stenosis diameter with 2D area stenosis measurements, with the hypothesis that the narrowest diameter is a good predictor of the more precise area measurement. METHODS: Two neuroradiologists evaluated 178 stenosed carotids in a blinded protocol. Carotid artery bulb stenosis was identified on axial CT angiography and measured in millimeters at its narrowest diameter. An AGFA Impax 4.5 Volume Tool (VT) using Hounsfield units was used to estimate the cross-sectional area of the contrast luminogram. Pearson correlation coefficients were calculated between the millimeter stenosis and the VT area, as well as between the VT area and the calculated area (radius based on narrowest diameter). Regression analysis was performed with the VT area and narrowest diameter datasets. RESULTS: Excellent interobserver correlation (correlation coefficients, 0.71-0.85; 2-tailed significance = .01) permitted averaging of measurement data. There is excellent correlation between the VT area and the narrowest diameter (correlation coefficient, 0.88; n = 176). The VT area was generally greater than the calculated area by an average of 2.77 mm2. There was excellent correlation between the VT area and the calculated area (correlation coefficient, 0.87; n = 176). Regression analysis shows the ability of the diameter measurements to predict corresponding area stenosis. CONCLUSION: Although some carotid stenoses are irregularly shaped and noncircular, measurement of the narrowest stenosis is a reasonably reliable predictor of the cross-sectional area.     

肺淋巴管癌病的多层螺旋CT分析

肺性淋巴管癌病(pulmonary lymphangitic carcinomatosis,PLC)以转移癌细胞在淋巴管内弥漫性生长为特征,是肺转移瘤中的一种特殊类型。X线表现易与其他肺间质性病变相混淆,临床确诊较困难。随着影像技术的发展,特别是多层螺旋CT的临床应用,PLC影像学诊断得以更加清晰显示。本文     

Lung tumor growth: assessment with CT--comparison of diameter and cross-sectional area with volume measurements

PURPOSE: To compare diameter and cross-sectional area measurements with volume measurements in the assessment of lung tumor growth with serial computed tomography (CT). MATERIALS AND METHODS: Patients with lung cancer who underwent at least one pair of chest CT examinations 25 or more days apart before treatment and with a tumor size of T1 (< or =3-cm diameter) at the initial CT examination were identified. A total of 63 patients (62 men, one woman) who underwent 93 pairs of CT examinations were included. Images obtained at each examination were displayed, and the maximum diameter, cross-sectional area, and volume of the tumor were measured. For each measurement, the change between examinations was assessed to determine whether the change reached a detection threshold for growth, as determined in a prior study with simulated tumors. Results were then compared between measurement methods, with volume change serving as the reference standard, by calculating Spearman rank-order coefficients between examinations. Tumor size or section width were also evaluated with the two-tailed Fisher exact probability test to determine if they affected agreement about tumor growth between measurement methods. RESULTS: Thresholds were as follows: diameter, 2.1 mm with hand-held calipers and 0.68 mm with electronic calipers; area, 9.4%; volume, 16.5%. The median time between examinations was 92 days (range, 25-1,221 days). Median diameter increased from 19.3 mm to 23.0 mm (19.2%), median area from 207 mm(2) to 267 mm(2) (29.0%), and median volume from 1,652 mm(3) to 2,443 mm(3) (47.9%). Growth assessment with these diameter (as assessed with hand-held and electronic calipers) and area thresholds disagreed with those obtained with volume in 34 (37%), 26 (28%), and 25 (27%) of the 93 pairs of CT examinations, respectively. Of diameter assessments with the hand-held caliper threshold, 28 (30%) were false-negative; false-negative results occurred with this diameter threshold and area threshold with examination intervals as long as 1 year. CONCLUSION: Growth assessment of T1 lung tumors on serial CT scans with nonvolumetric measurements frequently disagrees with growth assessment with volumetric measurements.     

门静脉内径值与CT门静脉成像密度达峰值及达峰时间的相关性研究

目的:通过测量不同门静脉内径值的CT门静脉成像密度达峰值和达峰时间,探讨门静脉内径值与门静脉成像密度达峰值及达峰时间的相关性。方法:将60例门静脉内径值介于12.0~22.0 mm的患者分为3组,每组均采取特定区域多时间点扫描。对扫描结果进行统计分析,绘制TDC。对每例门静脉扫描密度达峰值与门静脉内径值行线性相关性分析。结果:门静脉内径值12.0~15.0 mm组达峰时间为60 s,15.1~19.0 mm组为70 s,19.1~22.0 mm组为75 s。达峰时间随门静脉内径值增加而延迟。密度达峰值也随门静脉内径值的增大而降低(r~2=0.652,P0.001),门静脉内径值与达峰值回归方程:y=173.599-2.276x。结论:门静脉内径值与门静脉成像密度达峰时间呈正相关、与密度达峰值呈反向线性变化趋势。为获得最佳门静脉成像质量,应根据不同门静脉内径值选择最佳的扫描时间。     

Normative analysis of pulmonary vein drainage patterns on multidetector CT with measurements of pulmonary vein ostial diameter and distance to first bifurcation

RATIONALE AND OBJECTIVES: To document the frequency of normal and anomalous drainage patterns of the pulmonary veins, and to establish normal values for pulmonary vein ostial diameters, and distance to first bifurcation using multidetector computed tomography, as pertinent to ablation procedures for atrial fibrillation. MATERIALS AND METHODS: Two cardiothoracic radiologists retrospectively reviewed thin-section contrast material-enhanced multidetector computed tomography examinations of the thorax in 200 consecutive patients (38 females and 162 males), age 24-79 years (mean 52.8) referred for imaging before radiofrequency ablation therapy for atrial fibrillation. Pulmonary vein anatomy was based on both the number of venous ostia and the drainage patterns of pulmonary veins. Pulmonary vein ostial diameters and distance to first bifurcation of the four major pulmonary veins (right inferior and superior, left inferior and superior) and any additional pulmonary veins were measured at a workstation using both axial images and multiplanar reconstructions by two experienced cardiothoracic radiologists; the mean pulmonary vein diameter and the shortest distance to first bifurcation of the two measurements are reported. RESULTS: The majority of patients, 82% (164 patients) had four pulmonary veins, with a superior and inferior ostium on the right and a superior and inferior ostium on the left. Of the remainder, 9% (18 patients) had five veins, 4.5% (9 patients) had three veins, 3% (6 patients) had two anomalies each, and 0.5% (1 patient) had three anomalies. The middle lobe pulmonary vein drained into the right superior pulmonary vein in 83.5% of patients, directly into the left atrium in 11% of patients, and into the right inferior pulmonary vein in 5.5% of patients; 6.5% of patients had a single left pulmonary vein ostium. Mean pulmonary vein diameters with 95% confidence intervals at the ostia were as follows: right superior 17.6 (13.64-15.36) mm; left superior 16.6 (16.03-17.08) mm; right inferior 17.1 (16.58-17.55) mm; left inferior 14.8 (14.25-15.27) mm, and independent middle lobe 8.6 (8.27-8.86) mm. Mean distance to first bifurcation with 95% confidence intervals were: right superior 14.5 (17.02-18.23) mm; left superior 17.6 (16.63-18.53) mm; right inferior 7.0 (6.49-7.46) mm; left inferior 13.5 (12.83-14.16) mm, and independent middle lobe 8.4 (7.7-9.17) mm. CONCLUSION: Thin-section thoracic computed tomography demonstrates a greater variability of pulmonary venous drainage than previously described. There is greater variability of the right lung venous drainage compared to the left lung. Eighty-two percent of people have four standard pulmonary veins. There is significant variability in pulmonary vein diameter and distance to first bifurcation.     

Pulmonary involvement in Churg-Strauss syndrome: an analysis of CT,clinical, and pathologic findings

We tried to assess retrospectively thin-section CT findings of Churg-Strauss syndrome (CSS) in 25 patients and to compare these findings with clinical and histopathologic findings. Of 25 patients, 19 (76%) had parenchymal abnormalities at CT; small nodules (n = 12; 63%), ground-glass opacity (n = 10; 53%), bronchial wall thickening (n = 10; 53%), and consolidation (n = 8; 42%). Parenchymal abnormalities (n = 19) were categorizable as an airway pattern in 11 and an airspace pattern in eight. Patients with an airway pattern (n = 5) had obstructive (n = 3) or combined (n = 2) PFT results, whereas those with an airspace pattern (n = 4) had restrictive (n = 3) or obstructive (n = 1) results. Parenchymal opacities at CT corresponded histologically to areas of eosinophilic pneumonia, necrotizing granulomas, and granulomatous vasculitis; small nodules to eosinophilic bronchiolitis and peribronchiolar vasculitis; and bronchial wall thickening to airway wall eosinophil and lymphocyte infiltration. Patients with airspace pattern responded more readily to treatment than those with airway pattern. CT shows lung parenchymal abnormalities in about three-quarters of CSS patients and these abnormalities can be categorized as airspace or airway patterns. This classification helps predict PFT data, underlying histopathology, and treatment response.     

Anomalous brachiocephalic vein: CT, embryology, and clinical implications

OBJECTIVE: CT patterns of anomalous brachiocephalic veins are presented with reconsideration of the structure's embryogenesis. CONCLUSION: With advancements in central line procedures and corrective cardiac surgery, and the widespread use of noninvasive imaging techniques, the clinical importance of identification of the anomalous brachiocephalic vein is shown.     

肾移植术后肺部感染的CT特征

目的 回顾分析121例临床证实的肾移植术后肺部感染患者的临床及CT资料,以期获得肾移植术后肺部感染的特征性CT表现.方法 临床证实的肾移植术后肺部感染446例患者,行感染时间分析,其中有完整胸部CT检查资料的121例行病原种类及CT表现分析;影像结果分析采用X2检验及Fisher's精确检验.结果 (1)肺部感染时间特点:446例肾移植患者术后1个月内发病65例(14.6/),1～3个月147例(32.9/),4～6个月91例(20.4/),7～12个月23例(5.2/),1年以上120例(26.9/).移植术后1个月内细菌感染比例高(4/5);第1～6个月细菌(34/41,82.9/)、混合感染(19/41,46.3/)以及病毒感染(19/41,26.8/)为主;1年以后真菌(14/38,36.8/)、结核杆菌(5/38,13.2/)感染率明显增加.(2)病原体分布:121例行CT检查的肺部感染中细菌(34例,28.1/)和混合感染(34例,28.1/)最为常见,真菌(9例,7.4/)、结核(7例,5.8/)感染次之,病毒感染(5例,4.1/)最少.(3)CT特征:肾移植后肺部感染CT征象出现最多的是磨玻璃影(GGO)(69例,57.0/),其他依次为网格或线样影(68例,56.2/)、结节(66例,54.5/)、胸膜增厚(41例,33.9/)、实变(31例,25.6/)、树芽征(24例,19.8/)、胸腔积液(22例,18.2/)以及血管支气符束增粗(16例,13.2/)等征象,其中巨细胞病毒感染中以弥漫型GGO最常见(4例,80.0/),在细菌感染中结节最常见(23例,67.6/),树芽征在结核中最常见(4例,P=0.049),其他征象在各病原体感染中出现频率差异无统汁学意义(P值均＞0.05).结论 肾移植后肿部感染高峰为术后3个月左右;最常见的病原体足细菌,混合感染比例高;CT表现多样,需结合术后时间、实验室资料及病变分布等才能作出明确诊断.     

恶性肿瘤合并肺栓塞的CT肺动脉造影及临床表现分析

目的 探讨恶性肿瘤合并肺栓塞的CT肺动脉造影(CT pulmonary angiography,CTPA)和临床表现.方法 收集88例经CTPA诊断的肺栓塞病例,按是否伴有恶性肿瘤分成恶性肿瘤组(28例)和非肿瘤组(60例),分别测量肺动脉直径,左右心室的最大短轴直径及其比值,血栓密度,计算栓塞指数,记录栓塞部位、胸腔积液和肺内渗出性病变的发生情况.对恶性肿瘤组,按肿瘤部位分类统计,并对肺栓塞(PE)发生时间和临床表现作记录.结果 本组资料中央性肺栓塞恶性肿瘤组有22例(78%),非肿瘤组有34例(57%),P<0.05,显示恶性肿瘤合并肺栓塞者栓塞容易发生于中央性肺动脉;出现胸腔积液和肺内渗出性病变的几率恶性肿瘤组亦高于非肿瘤组;血栓密度、栓塞指数以及反映右心功能的指标2组无统计学差异.合并肺栓塞的恶性肿瘤以腺癌最多见,特别是进展期已发生转移的恶性肿瘤.结论 恶性肿瘤伴肺栓塞具有一些影像和临床特征,提高相关认识有助于临床诊断和进一步治疗.     

Mild intermittent asthma: CT assessment of bronchial cross-sectional area and lung attenuation at controlled lung volume

PURPOSE: To evaluate, with thin-section computed tomography (CT), changes in bronchial cross-sectional area and lung attenuation induced by bronchial stimulation in patients with mild intermittent asthma, at a given lung volume monitored with pneumotachography. MATERIALS AND METHODS: Twelve patients with mild intermittent asthma who were nonsmokers (National Institutes of Health staging) and six nonsmoking healthy volunteers, age and sex ratio-matched, were examined by using helical thin-collimation CT at the level of basal bronchi at 65% of total lung capacity. Three sets of acquisitions were obtained: at baseline and after inhalation of methacholine and then salbutamol. Cross-sectional areas of bronchi greater than 4 mm(2) were segmented and calculated from CT images. Lung attenuation was measured in the anterior, lateral, and posterior areas of the right lung parenchyma. Gas trapping was evaluated by using thin-section CT at residual volume in six of the patients with asthma. Statistical analysis included two factors repeated-measurement analysis of variance and Mann-Whitney and Kruskal-Wallis nonparametric tests. RESULTS: Bronchial cross-sectional areas and lung attenuation did not vary significantly compared with baseline values following bronchial challenge in healthy volunteers or patients with asthma. However, in patients with asthma, bronchial cross-sectional areas were significantly smaller than in healthy volunteers, except after inhalation of salbutamol. Lung attenuation and anteroposterior attenuation gradient were significantly higher in patients with asthma than in healthy patients (P <.001). Air-trapping scores were significantly higher after methacholine challenge. CONCLUSION: Helical thin-collimation CT at controlled lung volume and at full expiration associated with bronchial challenge may help evaluate bronchoreactivity and inflammation in mild intermittent asthma.     

Carotid stenosis degree in CT angiography: assessment based on luminal area versus luminal diameter measurements

The aim of this study was to investigate CT angiography (CTA) luminal area measurements in the assessment of carotid artery stenosis compared with the current clinically used criteria based on lumen diameter measurements. Seventy-two vessels in 36 patients were evaluated by CTA and digital subtraction angiography (DSA). Two observers measured area and diameter stenosis degrees using automated 3D CTA analysis software. The ratio of the largest/smallest luminal diameter at the level of maximal stenosis (L/S ratio) was used to describe lumen morphology. Diagnostic agreement between CTA and DSA was calculated. For the assessment of area stenosis, interobserver and intraobserver correlation coefficients were 0.898 and 0.906 (p<0.001). The correlation coefficient between the diameter stenosis and area stenosis was lower in stenoses with extremely noncircular lumen (L/S ratio 1.5) (r=0.797, p<0.001) compared with stenoses with circular lumen (LS ratio <1.2) (r=0.978, p<0.001). Only satisfactory agreement ( 0.54-0.77, p<0.001) was obtained between area stenosis on CTA and diameter stenosis on DSA. Assessment of stenosis degree with area measurements on 3D CTA proved to be reproducible. Area stenosis provides a less-severe estimate of the degree of carotid stenosis but might theoretically express the real hemodynamic significance of the lesion better than diameter stenosis, especially in stenoses with noncircular lumen.     

Pulmonary tumorlets: CT findings

OBJECTIVE: Pulmonary tumorlets are defined in pathologic terms as benign localized neuroendocrine cell proliferations a few millimeters in size that are usually associated with damaged and ectatic small airways. The purpose of this study was to determine the frequency with which pulmonary tumorlets can be seen on CT and to describe their CT appearance. CONCLUSION: In 33 patients with proven tumorlets, a nodule was visible on CT in the same region as that of the resected specimen. Despite its ominous-sounding name, a pulmonary tumorlet represents benign tissue that may manifest as a subcentimeter pulmonary nodule and should be considered in the differential diagnosis of small pulmonary nodules visible on CT.     

Pulmonary lymphangioleiomyomatosis: CT findings

Lymphangioleiomyomatosis, a rare disease occurring in women of childbearing age, is characterized by proliferation of smooth muscle in pulmonary lymphatic channels and mediastinal and abdominal lymph nodes. Chest radiographs typically reveal interstitial disease with normal lung volume. Pneumothorax and pleural effusions may be present. CT scans in eight patients with biopsy-proved pulmonary lymphangioleiomyomatosis were reviewed. The prominent feature of the disease was multiple thin-walled cysts throughout the lungs, best visualized on scans made with 1.5-mm collimation. Mediastinal and/or retrocrural lymphadenopathy, often not appreciated on the chest radiograph, was present in four of eight patients. CT can suggest a diagnosis of lymphangioleiomyomatosis when diagnosis by clinical presentation and chest radiographs is uncertain.     

Pulmonary hamartoma: CT findings

Forty-seven patients with a proved (n = 31) or presumed (n = 16) diagnosis of pulmonary hamartoma were studied prospectively by thin-section computed tomography (CT). CT criteria for hamartoma included a diameter of 2.5 cm or less, a smooth edge, and focal collections of fat or fat alternating with areas of calcification. No case of cancer (n = 283) or metastatic disease (n = 72) fulfilled these criteria. Seventeen hamartomas with no detectable calcium or fat were not diagnosed by means of CT. Two other lesions contained diffuse calcium deposits. In 28 lesions, a CT diagnosis of hamartoma was based on the detection of fat (n = 18) or calcium plus fat (n = 10). Twelve such cases were proved histologically by means of thoracotomy or needle biopsy; the remainder, including eight in asymptomatic patients aged 65 years or older, were managed with conservative follow-up.     

The occipitotemporal vein: a cadaver,MRI and CT study

The author studied a superficial temporal vein running anteroposteriorly within the occipitotemporal sulcus, the occipitotemporal vein, which, when prominent, could be thought to simulate a venous angioma on MRI. A cadaver (n=50), MRI (n=200), and CT (n=50) study was undertaken to examine the incidence, detectibility, size, location, and drainage of the occipitotemporal vein. It was an approximately 3 mm wide, 2–5 cm long structure. It was present in 83% of the cadavers (52% bilaterally), and clearly identifiable on 73% of the MRI (43% bilaterally), and 8% of the CT studies. In 18% of the cadavers the vein was totally absent, and it was not seen in 27% of the MRI examinations. The occipitotemporal vein can be distinguished from a venous angioma by its particular location and course, and by lack of intraluminal bright signal on spin-echo T2-weighted and/or contrast-enhanced T1-weighted images. In addition, venous angiomas are usually intraparenchymal, whereas the occipitotemporal vein is a superficial vessel.     

Pulmonary tuberculosis: CT and pathologic correlation

Typical CT findings of active postprimary pulmonary tuberculosis include centrilobular nodules and branching linear structures (tree-in-bud appearance), lobular consolidation, cavitation, and bronchial wall thickening. The CT findings of inactive pulmonary tuberculosis include calcified nodules or consolidation, irregular linear opacity, parenchymal bands, and pericicatricial emphysema. The typical appearance of primary tuberculosis on CT scans is homogeneous, dense, well-defined segmental or lobar consolidation with enlargement of lymph nodes in the hilum or the mediastinum. Miliary nodules may be seen in primary and postprimary tuberculosis. On CT, tuberculomas appear as a nodule with surrounding satellite nodules and internal cavitation on CT. Atypical radiologic manifestations of tuberculosis, encountered in as many as one third of the cases of adult-onset tuberculosis, are single or multiple nodules or masses, basilar infiltrates, miliary tuberculosis with diffuse bilateral areas of ground-glass opacity, and reversible multiple cysts. Underlying histopathologic findings of typical and atypical CT findings of tuberculosis are caseating granulomas or pneumonia in the active phase and fibrosis and dystrophic calcification in the inactive phase.     

肺硬化性血管瘤的X线、CT及病理对照分析

目的 探讨肺硬化性血管瘤(PSH)的影像学特点及其诊断价值.资料与方法回顾性分析经手术病理证实的20例PSH患者的胸部正、侧位片和胸部CT平扫及13例增强扫描资料.结果 20例PSH,19例为单发,1例为多发,共21个结节,胸片显示结节边缘光滑19个,边界不清2个.CT平扫结节呈圆形或类圓形,边界光滑锐利18个(86%),边界不光滑3个;密度均匀17个,不均匀4个.其中空气新月征1例,贴边血管征2例,尾征1例,肺动脉为主征1例.增强扫描病灶动脉期均匀强化10例,不均匀强化3例,静脉期仍呈渐进性强化.结论境界清晰、密度均匀、明显持续强化为PSH的主要表现.综合分析其他征象有益于提高诊断准确率.