CT评价胸腔积液量准确性的实验研究

目的评价CT测算胸腔积液量的准确性。方法采用GE—sytec 4000i全身CT扫描系统，对注水肺脏模型进行扫描。选取右侧肺脏共作15次测量。由一名熟练的CT操作人员在积液最明显的一层上用轨迹手工圈划出积液的完整轮廓，预设感兴趣区的CT值上下限范围0-20 HU，采用计算机体积测算功能，计算出各层满足上述要求的感兴趣区图像总体积。结果肺脏模型体积CT测值与实际注水量的散点图呈直线趋势，R^2=1.000。回归系数t检验的t值=681、077，P=0．0001（P〈0.001），可认为肺脏模型体积CT测值与实际注水量之间有直线关系；直线回归方程为：Y=-0．238＋0．999X。肺脏模型体积的标准差为893．27504，实际注水量的标准差为894．42719。肺脏模型体积CT测值与实际注水量的相关分析表明，肺脏模型体积CT测值与实际注水量高度相关（P〈0．001）。结论CT能够准确测量胸腔积液量，它有可能替代传统X线的粗略估算。     

CT评价气胸后肺组织压缩体积(百分比)准确性的研究

目的评价CT计算气胸后肺脏体积压缩的准确性.方法①采用岛津SCT-7000TH全身CT扫描系统对17个肺脏模型进行扫描,利用CT机的面积计算功能计算肺脏模型体积.②肺脏模型的实际体积通过注入水达到标定刻度所需水的容量来计算.结果肺脏模型实际体积为(2893.47±29.22)ml,CT计算值为2894.32±28.47.CT的计算值与模型的实际测值无显著性差异(Ρ＞0.05),两者有高度相关性(γ=0.9860,Ρ＜0.001).结论CT能够准确计算肺脏体积,是测量气胸患者肺脏压缩程度的准确方法.     

胸腔积液量的多层螺旋CT定量研究

目的探讨多层螺旋CT轴位测量数据预测胸腔积液量的准确性方法。方法回顾性分析129例胸腔积液患者的胸部CT扫描数据,用VR胸水体积测量其胸腔积液的量;在轴位图像上分别于膈顶、隆突下及主动脉弓下3个平面测量胸腔积液的厚度并分别用A、B、C值代表;将体积与各个平面胸腔积液的厚度分别进行1次回归(线性回归)、2次回归和3次回归分析,并从中挑选出模型和系数显著且解释度最大的回归方程式。结果所有回归模型均具有统计学意义(P<0.01)。膈顶平面预测胸腔积液方程式为:胸腔积液量(ml)=22.804×A-0.061×A2-106.399,R2=0.898;隆突下平面预测胸腔积液方程式为:胸腔积液量(ml)=37.841×B-0.204×B2-235.935,R2=0.924;主动脉弓下平面胸腔积液方程式为:胸腔积液量(ml)=31.825×C-0.140×C2-17.278,R2=0.846。结论胸腔积液的厚度均能预测胸腔积液的量,尤其是隆突下平面的径线能更准确地反映积液的量。     

64层螺旋CT容积再现测量胸腔积液体积及与测量参数的相关性

目的探讨64层螺旋CT容积再现(VR)技术精确测量胸腔积液体积及胸腔积液各径线之间的相关性。资料与方法 64层螺旋CT检出胸腔积液26例,其中双侧胸腔积液6例,通过AW4.4工作站VR技术进行图像处理,并利用其自动容积测量工具测得胸腔积液体积(V),分析胸腔积液体积与胸腔积液最大左右径(l)、最大上下径(h)和最大前后径(d)之间的相关性。结果利用CTVR技术测得胸腔积液体积(V)为(543.66±643.81)cm3,V与d的直线回归方程:V=158.16×d-116.01(r=0.91,P<0.01)。结论利用64层螺旋CT容积再现技术测得胸腔积液体积与积液最大前后径存在明显直线相关,并可得到相应的直线回归方程。     

多层螺旋CT测量胰腺体积的准确性评价

目的研究多层螺旋CT测量胰腺体积的准确性。资料与方法多层螺旋CT扫描胰腺模型及胰腺正常患有其他疾病的患者,由有5年以上CT工作经验的放射科医师测量胰腺体积并记录。结果胰腺模型体积CT测量值与实际值差异无统计学意义(t=1.648,P=0.134),这两者间的一致性很高(ICC=1.000,P=0.000);可重复性分析中,CT测量胰腺体积观察者内的差异及观察者间的差异无统计学意义(P>0.05),一致性很高(所有ICC>0.99,P=0.000)。结论多层螺旋CT测量胰腺体积准确、可靠,可重复性较高。     

Evaluation on Accuracy of Pancreatic Volume Using Multislice Spiral CT

目的 研究多层螺旋CT测量胰腺体积的准确性.资料与方法 多层螺旋CT扫描胰腺模型及胰腺正常患有其他疾病的患者,由有5年以上CT工作经验的放射科医师测量胰腺体积并记录.结果 胰腺模型体积CT测量值与实际值差异无统计学意义(t=1.648,P=0.134),这两者间的一致性很高(ICC=1.000,P=0.000);可重复性分析中,CT测量胰腺体积观察者内的差异及观察者间的差异无统计学意义(P＞0 05),一致性很高(所有ICC ＞0 99,P=0 000).结论 多层螺旋CT测量胰腺体积准确、可靠,可重复性较高.     

肿瘤靶体积测量16层CT成像参数的选择

目的:探讨16层CT在肿瘤靶体积测量中的应用.方法:在西门子Somatom Sensation16层CT机上以不同准直宽度(0.75mm、1.5mm)和不同螺距(0.5、1.0、1.5)对埋入蜡块中的实体瘤模型进行扫描,分别获取6组原始数据,每组数据采用2、3、5、8及10mm不同的重建间隔共计5组重建不同层厚的图像,在治疗计划系统上对所获图像勾画靶区,利用TPS的州量软件测得模体的体积数据.结果:不同重建层厚(2、3、5、8和10mm)所测量模体体积之均值分别为(25.55±0.08)、(25.44±0.11)、(25.36±0.17)、(21.72±0.77)和(20.55±0.03)cm3,与实际体积值(25.62 cm3)配对t检验,2、3、5 mm相对应之P值均大于0.05,8、10mm相对应之P值均小于0.01.不同准直及不同螺距在2mm重建层厚条件下的测量结果误差的直线回归分析y=0.028x 25.55(r=1.00,P＜0.01),3、5、8、10mm重建层厚之直线回归方程的斜率分别为0.031、0.027、0.034、0.011(r=1.00,P＜0.01).结论:多层螺旋CT模拟对肿瘤靶体积的测量误差与准直宽度和螺距无关,而与重建层厚有关,且2mm、3mm和5mm的重建层厚所获之体积数据最接近实际值.     

宝石能谱CT在结核性胸腔积液和癌性胸腔积液鉴别诊断中的应用

目的 探讨宝石能谱CT在结核性胸腔积液和癌性胸腔积液鉴别诊断中的应用价值.资料与方法 经临床确诊的8例结核性胸腔积液和8例癌性胸腔积液患者行宝石能谱扫描,分别测定结核性胸腔积液和癌性胸腔积液的混合能量CT值、能谱曲线斜率、脂基密度值、血基密度值及有效原子序数值,并进行比较.结果 结核性胸腔积液和癌性胸腔积液的能谱曲线互相交叉、重叠,无特定的分布规律；结核性胸腔积液和癌性胸腔积液的混合能量CT值、能谱曲线斜率、脂基密度值、血基密度值及有效原子序数比较,差异均无统计学意义(t=-0.891、0.69、0.085、0.581、0.201,P＞0.05).结论 宝石能谱CT的能谱成像中混合能量CT值、能谱曲线斜率、脂基密度值、血基密度值及有效原子序数尚不能用于鉴别诊断结核性胸腔积液和癌性胸腔积液.     

低剂量64层螺旋CT测定冠状动脉钙化积分的准确性评价

目的 探讨低剂量64层螺旋CT测定冠状动脉钙化积分的准确性。方法 2006年8月至2009年9月间对43名冠状动脉钙化的患者连续进行2次64层螺旋CT扫描,管电流时间积分别为常规剂量(100 mAs)和低剂量(55 mAs),其余参数不变,由2名放射科副主任医师测定钙化积分并测量升主动脉CT值的均数及标准差。结果 低剂量与常规剂量钙化总积分和独立血管钙化积分取平方根转换后均直线相关(r =0.998、0.997)。低剂量管电流时间积所测升主动脉根部的CT值的均数与2倍标准差之和小于130 HU,可满足所要求的信噪比,与常规剂量扫描辐射剂量(1.32±0.08)mSv相比较,低剂量扫描有效剂量降低0.6 mSv(P <0.05)。结论 低剂量前瞻性心电门控64层MDCT钙化积分扫描图像能满足测量需要,测量结果具有较高的准确性。     

基于CUBE-FSE-FLEX序列的体外模型脂肪定量研究

目的采用CUBE-FSE-FLEX序列测量水脂混合溶液模型的脂肪浓度、猪瘦肉及肥肉容积,研究基于此技术的脂肪浓度定量及容积测量准确性。方法(1)水脂混合模型:分别制作浓度范围2%~30%、浓度梯度为2%的脂肪乳溶液和浓度范围0%~100%、浓度梯度为10%的水脂溶液,分别采用CUBE-FSE-FLEX和IDEAL-IQ序列扫描水脂溶液和脂肪乳溶液模型,获得两组序列所测脂肪分数,采用配对t检验分别比较两组测量值与实际脂肪分数的差异,采用线性回归方法及Bland-Altman散点图分析两组测量值与实际脂肪浓度的相关性及一致性;(2)肥瘦肉模型:采用CUBE-FSE-FLEX序列扫描肥瘦肉模型,分别获得手工分割(MS)和半自动分割算法[多维阈值法(MDT)及区域增长法(RG)]测量的肥肉和瘦肉样本的体积,采用配对t检验、Pearson相关法及Bland-Altman散点图行3种方法容积测量值与实际容积的差异性、相关性及一致性检验;对肥瘦肉模型采用的MDT测得值进行Pearson相关法及Bland-Altman散点图分析。结果(1)水脂溶液:CUBE-FSE-FLEX-FaF与实际脂肪浓度无显著性差异(t=0.113,P=0.913),IDEAL-IQ-FaF与实际浓度差异显著(t=-41.084,P<0.001),两种测量值与实际脂肪浓度均有高度直线相关,分别为0.941(CUBE-FSE-FLEX)与1(IDEAL-IQ)。测量值与实际值差值的95%置信区间为:CUBE-FSE-FLEX(-19.1708,18.5199),IDEAL IQ(-4.7593,-3.4589)。(2)脂肪乳溶液:CUBE-FSE-FLEX及IDEAL-IQ测量值与实际脂肪浓度均有显著性差异,(t=34.668,P<0.001)、(t=21.363,P<0.001),与实际脂肪浓度均呈高度直线相关,R^2分别为0.999(CUBE-FSE-FLEX)与1(IDEAL-IQ),测量值与实际值差值的95%置信区间为:CUBE-FSE-FLEX(-4.1762,-2.68),IDEAL-IQ(-2.0076,0.990)。(3)肥瘦肉模型:配对t检验示肥瘦肉模型MS测量值与实际值均无显著差异(t=0.777,P=0.443;t=1.727,P=0.94);MDT及RG测量值与实际值均有显著差异(P<0.001)。肥瘦肉模型中三种测量值均与实际容积值高度相关(R^2均>0.98),MS与实际值偏差最小(bias=1.49%,bias=2.88%),MDT次之(bias=14.7%,bias=12.8%),RG最大(bias=-27.31%,bias=-33.99%),测量值与实际差值的95%置信区间分别为:肥肉模型-19.73%,-22.70%(MS);-22.76%,-52.15%(MDT),-40.84%,-13.79%(RG);瘦肉模型-15.62%,-21.38%(MS);-8.12%,-33.71%(MDT),-51.43%,-22.55%(RG)。对肥瘦肉采用MDT测量方法两次测量值统计分析,两次采用MDT方法的测量值相关性及一致性高。结论应用CUBE-FSE-FLEX序列能客观反映体外模型的脂肪浓度变化,推荐该序列脂像或水像图结合MDT可相对准确、便捷的实现软组织容积测量,可满足临床中组织器官的脂肪含量定量及容积测量的需要。     

Estimating normal lung weight measurement using postmortem CT in forensic cases

PurposeThe aim of this study is to estimate the lung weight using postmortem CT in well aerated lung autopsy cases. The correlation coefficients to the lung weight were also evaluated for the cadavers’ height, weight, whole body surface area (WBSA), body mass index, and estimated lung volume.Materials and methodsFrom October 2015 to July 2016, 31 cadavers (male 12, female 19, age 20–98 (mean 66.9) y.o., postmortem interval 0.3–75.0 (5.7) days) were compared as regards body weight, height, whole body surface area (WBSA), body mass index (BMI), lung volume on CT, and total lung volume classified into several CT number categories, with their lung weight in autopsy.ResultsThe lung weight (mean ± SE) was 284.9 ± 14.8 g in right lung and 249.3 ± 12.9 g in left lung. The %ALV was 79.9 ± 0.9 HU (mean ± standard error (SE)) in both lungs, 80.3 ± 1.3 HU in right lung, and 77.6 ± 2.0 HU in left lung. Using a simple linear regression test, there was no statistically significant correlation between the lung weight and the categories (R²: body height 0.234, weight 0.224, WBSA 0.309, BMI 0.046, lung volume 0.059). The volume for each individual CT density category showed no significant correlation, but the stepwise regression test yielded an excellent correlation coefficient (R² = 0.840).ConclusionThe well aerated lung weight was 284.9 ± 14.8 g in right lung and 249.3 ± 12.9 g in left lung, and the postmortem CT could estimate the lung weight with high correlation coefficient.     

Interstitial Myocardial Fibrosis Assessed as Extracellular Volume Fraction with Low-Radiation-Dose Cardiac CT

Purpose: To develop a cardiac computed tomographic (CT) method with which to determine extracellular volume (ECV) fraction, with cardiac magnetic resonance (MR) imaging as the reference standard. Materials and Methods: Study participants provided written informed consent to participate in this institutional review board-approved study. ECV was measured in healthy subjects and patients with heart failure by using cardiac CT and cardiac MR imaging. Paired Student t test, linear regression analysis, and Pearson correlation analysis were used to determine the relationship between cardiac CT and MR imaging ECV values and clinical parameters. Results: Twenty-four subjects were studied. There was good correlation between myocardial ECV measured at cardiac MR imaging and that measured at cardiac CT (r = 0.82, P < .001). As expected, ECV was higher in patients with heart failure than in healthy control subjects for both cardiac CT and cardiac MR imaging (P = .03, respectively). For both cardiac MR imaging and cardiac CT, ECV was positively associated with end diastolic and end systolic volume and inversely related to ejection fraction (P < .05 for all). Mean radiation dose was 1.98 mSv ± 0.16 (standard deviation) for each cardiac CT acquisition. Conclusion: ECV at cardiac CT and that at cardiac MR imaging showed good correlation, suggesting the potential for myocardial tissue characterization with cardiac CT. ? RSNA, 2012.     

Automatic evaluation of total lung capacity and of emphysema involvement with spiral computerized tomography (CT) in obstructive pneumonia

OBJECTIVE: To evaluate, in patients with chronic obstructive lung disease or chronic bronchitis, inspiratory helical CT with 3D postprocessing, to measure lung volumes and the amount of emphysema and to compare these measurements with lung function tests. MATERIAL AND METHODS: Seventeen patients with chronic obstructive lung disease disease or chronic bronchitis underwent pulmonary function tests and helical CT after a full inspiration with 3D postprocessing (lower threshold -1024 HU, upper thresholds -200, -300 and -400 HU). Lung inspiratory volumes (TLC-CT) were determined for each model; the amount of emphysema was evaluated by means of an automatic score and a visual score with HRCT. RESULTS: There is a good correlation between automatic and visual scores (p < 0.001); the automatic score had a good correlation with lung function tests, above all with total lung capacity (r = -0.56; p = 0.01) but the visual score had a much closer correlation with DLCO (r = -0.70; p < 0.001). TLC-CT had a significant correlation with pletismographic TLC (TLC-P); the upper threshold -200 HU was more correct (TLC-P = 8011 cc.; TLC-CT 200 = 7138 cc.; r = 0.83; p < 0.001). The volume change of 3D model was about 230 cc. per 100 HU (p < 0.001) modifying upper thresholds, but no change was observed in the volume occupied by emphysema and the percentage of emphysema presented minimal, clinically non significant modifications. DISCUSSION AND CONCLUSIONS: In emphysematous patients, the helical CT with 3D model construction is a good technique to evaluate lung volumes and to quantify emphysema with automatic score; this one, however, probably underscores the extent of pathology; therefore, the addition of a visual score with HRCT is probably worthwhile.     

Hydrocephalus: Ventricular Volume Quantification Using Three-Dimensional Brain CT Data and Semiautomatic Three-Dimensional Threshold-Based Segmentation Approach

ObjectiveTo evaluate the usefulness of the ventricular volume percentage quantified using three-dimensional (3D) brain computed tomography (CT) data for interpreting serial changes in hydrocephalus.Materials and MethodsIntracranial and ventricular volumes were quantified using the semiautomatic 3D threshold-based segmentation approach for 113 brain CT examinations (age at brain CT examination ≤ 18 years) in 38 patients with hydrocephalus. Changes in ventricular volume percentage were calculated using 75 serial brain CT pairs (time interval 173.6 ± 234.9 days) and compared with the conventional assessment of changes in hydrocephalus (increased, unchanged, or decreased). A cut-off value for the diagnosis of no change in hydrocephalus was calculated using receiver operating characteristic curve analysis. The reproducibility of the volumetric measurements was assessed using the intraclass correlation coefficient on a subset of 20 brain CT examinations.ResultsMean intracranial volume, ventricular volume, and ventricular volume percentage were 1284.6 ± 297.1 cm³, 249.0 ± 150.8 cm³, and 19.9 ± 12.8%, respectively. The volumetric measurements were highly reproducible (intraclass correlation coefficient = 1.0). Serial changes (0.8 ± 0.6%) in ventricular volume percentage in the unchanged group (n = 28) were significantly smaller than those in the increased and decreased groups (6.8 ± 4.3% and 5.6 ± 4.2%, respectively; p = 0.001 and p < 0.001, respectively; n = 11 and n = 36, respectively). The ventricular volume percentage was an excellent parameter for evaluating the degree of hydrocephalus (area under the receiver operating characteristic curve = 0.975; 95% confidence interval, 0.948–1.000; p < 0.001). With a cut-off value of 2.4%, the diagnosis of unchanged hydrocephalus could be made with 83.0% sensitivity and 100.0% specificity.ConclusionThe ventricular volume percentage quantified using 3D brain CT data is useful for interpreting serial changes in hydrocephalus.     

Quantitative diagnosis of fatty liver with dual-energy CT. An experimental study in rabbits

OBJECTIVES: To explore the correlation between fatty content of fatty liver and the difference of CT attenuation value in dual-energy CT, and to evaluate the value of dual-energy CT in the quantitative diagnosis of fatty liver in rabbits. MATERIAL AND METHODS: Dual-energy CT at 120 kVp and 90 kVp was performed in 16 rabbits of experimental groups that were induced to various degrees of fatty liver by feeding carbon tetrachloride (CCl4). Four healthy rabbits in the control group underwent dual-energy CT at the same time. The CT attenuation values of liver tissues at 120 kVp (H120), 90 kVp (H90) and the difference (Delta H) between them were obtained. The specimens of liver tissues were examined with freeze section (9 microm) and an oil red O stain histologically. The ratio of fatty content in liver to the liver volume (VP value) was measured using the image analyzer system. RESULTS: The change of CT attenuation values between 120 kVp and 90 kVp was not obvious (Delta H between -0.4 HU and 1.4 HU) in the control group. The density of the liver in the experimental groups decreased differently, and the change in CT attenuation values between high and low energy levels were very clear. H120 values were between 51.0 HU and 91.7 HU and H90 values were between 37.0 HU and 89.2 HU. Delta H values were between 2.5 HU and 14.0 HU. Significant negative linear correlation (r = -0.92, -0.93, t = 8.51, 9.76, p < 0.001, 0.001, respectively) were found between VP values and H120 and H90, respectively, while significant positive linear correlation (r = 0.95, t = 11.89, p < 0.001) was found between VP values and Delta H. CONCLUSION: The amount and degree of fat in the fatty liver can be assessed exactly by dual-energy CT. It will be a potential new effective method for quantitative diagnosis of fatty livers.     

16层螺旋CT灌注成像强化指标和肿瘤微血管密度与肺癌淋巴结转移的关系

目的 应用16层MSCT灌注成像定量评价肺癌肿瘤血管生成,并探讨CT灌注成像强化指标和肿瘤微血管密度(MVD)与肺癌淋巴结转移的关系及其价值.方法 对53例周围型肺癌行CT灌注扫描,根据首过期肿块强化的时间-密度曲线(TDC)计算肿瘤的灌注强化指标,根据病理结果分为有淋巴结转移组和无淋巴结转移组,并对肿瘤MVD计数.淋巴结转移组与无转移组各观察指标的差异采用t检验或t'检验;将CT灌注强化指标分别与MVD做相关性分析;利用ROC曲线分析MVD和CT灌注强化指标评价肺癌淋巴结转移的诊断效能.结果 (1)肺癌淋巴结转移组(26例)MVD计数高于无淋巴结转移组(27例),MVD分别为(64.69±16.34)、(42.67±16.78)个/0.74 mm~2(t=4.84,P<0.01).淋巴结转移组肿块的强化峰值(PH)、肿块与主动脉PH之比(M/A)、灌注值(PV)均高于无淋巴结转移组[PH分别为(41.79±15.50)、(29.99±10.91)HU;M/A分别为0.24±0.09、0.15±0.06;PV分别为(2.14±1.09)、(1.27±0.53)ml·min~(-1)·ml~(-1)];差异均有统计学意义(t值分别为3.21、3.95、3.66,P均<0.01).(2)PH、M/A、PV均与MVD呈正相关,其中PV与MVD的相关系数最高(r=0.716,P<0.01).(3)利用ROC曲线分析,MVD、PV判断肺癌淋巴结转移有较高的诊断价值(曲线下面积分别为0.828、0.849,P>0.05);当以MVD>52个/0.74 mm~2或PV>1.52 ml·min~(-1)·m~l(-1)作为强烈提示肺癌淋巴结转移的可能性时,其敏感性、特异性、诊断符合率均较高(分别为80.8%、81.5%、81.1%和84.6%、85.2%、84.9%).结论 CT灌注强化指标PV及MVD与肺癌淋巴结转移存在密切关系,PV可作为术前判断肺癌淋巴结转移的重要指标之一.     

迭代模型重建技术在肺动脉“双低”成像中的应用研究

目的：探讨迭代模型重建(IMR)技术在肺动脉低剂量、低对比剂成像中的应用价值。方法对60例临床怀疑肺动脉栓塞(PE)患者行256层螺旋CT肺动脉成像,根据随机表法将患者随机分为实验组、对照组,每组30例。实验组原始数据分别采用滤波反投射(FBP)、IMR技术重建图像(A、B组),对照组原始数据采用 FBP 重建(C 组)。采用5分制方法评价肺动脉主干及其分支的图像质量,测量并计算肺动脉强化值(CT 值)、图像噪声值、图像信噪比(SNR)、对比噪声比(CNR),记录 CT 容积剂量指数(CTDIvol)、剂量长度乘积(DLP),计算有效剂量(ED)。比较 A组与 B组,B组与 C组肺动脉 CT值、图像噪声、SNR、CNR 及主观图像质量。结果实验组与对照组体质量指数(BMI)差异无统计学意义(P=0.096)。实验组CTDIvol、ED低于对照组(P<0.001)。A、B组肺动脉CT值差异无统计学意义(P=0.999),B组肺动脉CT值高于C组(P=0.005)。B组图像噪声明显低于A组(P<0.001),B组图像噪声高于C组(P<0.001)。B组 SNR、CNR高于 A组(P<0.001),B、C组 SNR、CNR差异无统计学意义(P=0.831,P=0.958)。B组图像可诊断率、优良率高于 A组(P<0.001),B、C 2组图像优良率差异无统计学意义(P=1.000)。结论肺动脉“双低”成像扫描模式联合更优化的迭代重建技术的应用,能够保证图像质量的同时大幅度降低患者辐射剂量及对比剂应用。     

Correlation of lung parenchymal MR signal intensity with pulmonary function tests and quantitative computed tomography (CT) evaluation: a pilot study

PURPOSE: To evaluate the effect of ventilatory impairment on MR signal intensity of the lung parenchyma. MATERIALS AND METHODS: Subjects were five normal volunteers (age = 30 +/- 7.9 years, mean +/- SD) and 19 male patients with chronic obstructive lung disease (COPD) (mean age = 70.4 +/- 6.5 years). Coronal MR images were obtained over entire lung fields at full inspiration and full expiration with cardiac triggering on a 1.5T system. Changes in the mean lung intensity between the two respiratory states were normalized by each intercept of the linear regression lines of the signal changes, and the slope of the relationship was calculated. Computed tomography (CT) images were also obtained in COPD patients at full inspiration using a multidetector row CT scanner. Attenuation values less than -950 Hounsfield units (HU) (RA-950) represented the percentage of relative lung area on the CT. RESULTS: The mean slope of COPD patients (0.365 +/- 0.074) was less steep than that of the normal subjects (0.570 +/- 0.124, P < 0.001). In COPD patients, the slope correlated significantly with forced expiratory volume in one second (FEV1, r = 0.508, P = 0.026), but not with RA-950. CONCLUSION: In COPD patients, lung signal change measured by MRI correlates with airflow obstruction, but not with volume of the emphysema measured by lung CT.