Hyperpolarised 3He MRI and 81mKr SPECT in chronic obstructive pulmonary disease

Purpose During recent years, magnetic resonance imaging (MRI) using hyperpolarised (HP) ³He gas has emerged as a promising new method for the imaging of lung ventilation. However, systematic comparisons with nuclear medicine techniques have not yet been performed. The aim of this study was to compare ventilation imaging methods in 26 patients with chronic obstructive pulmonary disease (COPD) and nine lung healthy volunteers.Methods HP ³He MRI, ^81mKr single-photon emission computed tomography (SPECT), high-resolution computed tomography (HRCT) and pulmonary function tests were performed. The three scans were scored visually as percentage of non-ventilated/diseased lung, and a computer-based objective measure of the ventilated volume in HP ³He MRI and ^81mKr SPECT and an emphysema index in HRCT were calculated.Results We found a good correlation between HP ³He MRI and ^81mKr SPECT for both visual defect score (r=0.80, p<0.0001) and objective estimate of ventilation (r=0.45, p=0.0157). In addition, both scans were well correlated with reference methods for the diagnosis of emphysema (pulmonary function test and HRCT). The defect scores were largest on ^81mKr SPECT (the score on HP ³He MRI was one-third less than that on ^81mKr SPECT), but the difference was reduced after normalisation for different breathing depths (HP ³He MRI at total lung capacity; ^81mKr SPECT at tidal breathing at functional residual capacity).Conclusion HP ³He MRI provides detailed ventilation distribution images and defect scores are comparable on HP ³He MRI and ^81mKr SPECT. Additionally, new insights into the regional pulmonary microstructure via the apparent diffusion coefficient measurements are provided by HP ³He MRI. HP ³He MRI is a promising new diagnostic tool for the assessment of ventilation distribution.     

慢性阻塞性肺疾病病人右心室功能改变的影像学研究进展

慢性阻塞性肺疾病（COPD）是临床常见的慢性呼吸系统疾病,常继发右心功能不全,增加病人死亡风险。COPD病人右心室功能改变的精准及多方式影像评价已成为研究的热点。超声心动图、CT、心脏MR成像、放射性核素等成像技术是目前无创性评价COPD右心室功能改变的主要方法。就COPD导致右心室功能改变的机制以及各种影像技术的应用进展及其优劣予以综述。     

Imaging phenotypes of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is one of the leading causes of morbidity and mortality worldwide. COPD is defined by irreversible airflow obstruction. It is a heterogeneous disease affecting the airways and/or the parenchyma with different severity during the course of the disease. These different aspects of COPD can be addressed by imaging using a combination of morphological and functional techniques. Computed tomography (CT) is the technique of choice for morphological imaging of the lung parenchyma and airways. This morphological information is to be accomplished by functional information about ventilation and perfusion, mainly provided by magnetic resonance imaging (MRI). The comprehensive diagnostic possibilities of CT complemented by MRI will allow for a more sensitive detection, phenotype-driven characterization, and dedicated therapy monitoring of the disease.     

多层螺旋CT灌注成像对慢性阻塞性肺疾病的诊断价值

目的 研究CT灌注成像对慢性阻塞性肺疾病(COPD)的诊断价值.方法 20例COPD患者和20例志愿者行8层螺旋CT灌注成像,采用电影扫描(cine)方式,层厚5 mm,扫描时间0.5 s/层,注射对比剂后延时5 s,总扫描时间为45 s,测量感兴趣区血流量、血容量、平均通过时间及表面通透性和时间-密度曲线.结果 COPD患者的时间-密度曲线较志愿者曲线平坦,峰值明显降低.COPD患者血流量[(24.77±11.49)ml·min-1·100 g-1]、血容量[(2.48±1.02)ml/100 g]及表面通透性[(2.75±1.13)ml·min-1·100 g-1]明显低于志愿者[血流量(290.14±107.59)ml·min-1·100 g-1、血容量(16.51±5.98)ml/100 g、表面通透性(8.80±3.03)ml·min-1·100 g-1];平均通过时间[(10.58±4.85)s]高于志愿者[(4.50±1.71)s],差异均具有统计学意义(P<0.01).结论 多层螺旋CT肺灌注扫描对COPD的诊断有一定的辅助作用.     

慢性阻塞性肺疾病右心室功能影像学研究新进展

右心室功能的准确评估对慢性阻塞性肺疾病（COPD）的临床诊断及治疗至关重要。鉴于右心室几何形状复杂,传统影像检查方法对于其功能评价的准确性受到制约。近年来随着超声心动图组织多普勒成像(TDI)及应变率成像（SRI）技术的临床应用,多层螺旋ＣＴ时间分辨率提高及对比剂注射方案的优化,CMRI电影及相位对比技术的发展,放射性核素的各种新技术在心脏形态和功能评价中取得突破,使得影像技术客观、准确、定量地评估COPD病人右心室功能成为可能。     

CT双相扫描三维定量分析慢性阻塞性肺疾病CT肺功能与常规肺功能的关系

目的 应用64层螺旋CT双相扫描三维定量分析慢性阻塞性肺疾病(COPD)患者CT定量肺功能与常规肺功能(PFT)之间的关系,并评估CT定量分析肺功能在COPD患者中的应用价值.方法 收集84例COPD患者,采用64层螺旋CT扫描机,于深吸气末和深呼气末分别对患者行全肺扫描.采用全自动后处理软件,三维定量分析CT肺气肿参数和空气潴留评估参数.应用Spearman相关系数和多元线性回归分析CT肺功能参数与PFT之间的关系.结果 CT肺气肿评估参数最低1％衰减值[Perc1,(-984.28±17.93)HU]、最低15％衰减值[Perc15,(-948.35±22.26) HU]与片力呼气容积实测值与预计值百分比(FEV1％,48.69±23,47),第1秒用力呼气容积与用力肺活量比[FEV1/FVC,(45.89±15.36)％呈正相关(r=0.45 ～0.67,P＜O.01),与残气比[RV/TLC,(61.32±14.48)％]呈负相关(r=-0.33～-0.42,P＜0.01).CT评估肺气肿指数(EI)和空气潴留评估参数:-860～-950 HU范围内呼气相、吸气相衰减区占全肺容积百分比的差值[RVC-860～-950,(17.66±22.36)％]、呼气相与吸气相CT平均肺密度比值(MLDex/in,0.93 ±0.06)、呼气相与吸气相CT全肺容积比(LVeex/im,0.71 ±0.14)与FEV1％、FEV1/FVC呈负相关(r=-0.48～-0.69,P＜0.01);CT评估肺气肿参数[EI,(18.43±13.60)％]和空气潴留评估参数(RVC-860 ～-950、MLDex/in、LVeex/in)与RV/TLC呈正相关(r=0.41 ～0.66,P＜0.01).随后一元线性回归分析表明,CT肺气肿评估参数(EI 、Perc1、Perc15)和CT空气潴留评估参数(RVC-860～-950、MLDeex/in、LVeex/in)的变化与常规PFT参数间具有关联性(R2值0.27 ～O.66,P＜0.01);进一步将CT肺气肿与空气潴留参数两两结合成CT肺功能模型,进行多元线性回归分析(R2=0.66～0.85,P＜0.01),较单独分析时明显提高.结论 COPD患者CT肺气肿和空气潴留参数二者分别与PFT具有线性相关性,能够有效反映患者肺功能变化.CT肺气肿参数和空气潴留参数组成相关模型联合分析,与PFT相关性更好,更精确地反映了COPD患者肺功能的变化.     

合并左心室受累的致心律不齐性右室型心肌病的组织学和MRI表现

目的：探讨终末期致心律不齐性右室型心肌病（ARVC）组织学特点和MRI特征。方法9例患者接受心脏移植，移植后离体心脏行组织病理学检查。7例移植前行MR扫描。结果：病理学检查显示所有心脏双室受累，右心室腔显著扩张7例，大致正常2例。右心室壁均显示严重透壁性肌肉丧失，其中3例几乎完全被脂肪组织替代，6例几乎完全被纤维脂肪组织替代。左心室中重度扩张8例、轻度扩张1例。左心室游离壁受累者7例，室间隔和左心室游离壁同时受累者2例。5例以脂肪细胞浸润为主伴小灶性纤维化；4例以弥漫性纤维化为主，伴灶性脂肪细胞浸润。7例MRI显示左心室射血分数平均（21．66±7．05）％，左心室轻度扩张3例，中度扩张2例，高度扩张2例。右心室腔明显扩大、壁薄者5例，其中3例可见线状高信号脂肪浸润；其余2例右心室形态、大小及信号均无明显异常，仅突出地表现为左心室受累。2例显示心外膜下脂肪信号浸润，选择性累及左心室，心尖和侧、后壁；3例左心室节段性变薄伴运动功能丧失分别累及室间隔、心尖和侧后壁；4例左心室游离壁变薄，厚度不足5mm。5例心肌灌注延迟显像均表现为不同程度的增强，左心室侧后壁强化者4例，其中透壁性和心外膜下各2例；室间隔肌壁间强化者2例；左心室心尖部强化者2例，灶性和透壁性各1例。4例患者右心室壁亦可见透壁性增强，其中累及右心室游离壁者2例，累及右心室心尖和后壁各1例。结论：ARVC合并左心室受累是该组患者的特点，MRI不仅能够准确地反映ARVC继发性的心室扩张及室壁运动的节段性变化，而且能检出心室壁的脂肪浸润以及纤维化等，因此能够在一定程度上反映生理状态下心脏组织学特征。     

Evaluation of right ventricular function by 64-row CT in patients with chronic obstructive pulmonary disease and cor pulmonale

Purpose

The aim of this study was to investigate the clinical application value of right ventricle (RV) function measured by 64 multi-detector row CT (MDCT) in patients with chronic obstructive pulmonary disease (COPD) and cor pulmonale.

Materials and methods

Sixty-three consecutive patients with COPD and cor pulmonale were referred for electrocardiographically gated MDCT for evaluation of suspected or known coronary artery disease. Magnetic resonance imaging (MRI) for cardiac function analysis was performed on the same day. The MDCT and MRI examinations were successfully completed in 58 patients. Forty-six patients with COPD were divided into three groups according to the severity of disease by the pulmonary function test (PFT). Twelve patients diagnosed as cor pulmonale and 32 control subjects were also included. The RV function and myocardial mass (MM) were obtained by 64-MDCT and 1.5 T cardiac MRI in all of the groups. The results were compared among the groups using the Newman–Keuls method. Pearson's correlation was used to evaluate the relationship between the right ventricular ejection fraction (RVEF) and MM with the PFT results in COPD and cor pulmonale patients.

Results

The RVEF was significantly lower in patients with severe COPD and cor pulmonale than it was in those patients with mild or moderate COPD (P < 0.01). There were strong correlations between MDCT and MRI (r = 0.826 for RV MM, r = 0.982 and 0.969 for RV EDV and RV ESV, r = 0.899 for RVEF) and between MDCT results and forced expiratory volume in 1 s (r = 0.787 for RVEF, r = −0.774 for RV MM) in all patients.

Conclusion

MDCT can accurately quantify RV function and MM. The RVEF and RV MM measured by MDCT correlate well with the severity of disease as determined by PFT in patients with COPD and cor pulmonale. The assessment of right ventricular function is clinically important for evaluation of the severity of COPD, which may provide an objective basis for therapeutic strategy.     

组织多普勒成像技术在慢性阻塞性肺病患者左室功能评价中应用

目的探讨组织多普勒成像(TDI)技术的时间间隔指标在评价慢性阻塞性肺病(COPD)患者左室功能中的应用。方法选取临床确诊且病情稳定的COPD患者68例为COPD组,计算常规超声心动指标和TDI时间间隔指标,包括收缩时间(ST),射血时间(ET),充盈时间(FT)等容收缩时间(IVCT),并计算IVCT/ET,IVRT/FT和心肌组织性能指标(MPI),即(IVCT+IVRT)/ET。选择同期健康老人(年龄>60岁)50例为对照组。结果在常规超声心动指标中,COPD患者较对照组E峰速度减低,A峰速度升高,E/A比值减小,E峰减速时间(EDT)延长,差异有统计学意义(P<0.05)。TDI时间间隔指标中,IVCT与IVRT明显延长,ET、ST、FT明显缩短,IVCT/ET及IVRT/FT均明显增加,MPI明显增大,差异有统计学意义(P<0.05)。结论 TDI技术时间间隔指标能够为评价COPD患者左室功能提供有价值信息。     

Comparison between tagged MRI and standard cine MRI for evaluation of left ventricular ejection fraction

Global left ventricular function is a prognostic indicator and is used to evaluate therapeutical interventions in patients with heart failure. Regional left ventricular function can be determined with tagged MRI. Assessment of global left ventricular function using the tagging data may have additional clinical value without incurring extra scanning time, which is currently a limiting factor in cardiac imaging. Direct determination of end-diastolic volume is not possible with conventional tagged MRI. However, end-systolic volume can be directly measured because myocardium–blood contrast improves through a tagged image series. We investigated the potential of tagged MRI using frequency-domain analysis software to retrospectively track end-diastolic contour from end-systolic contour and subsequently calculate the ejection fraction. Tagged MRI was compared with the standard bright-blood cine MRI in healthy volunteers (n=20) and patients with previous myocardial infarction (n=8). Left ventricular ejection fraction derived from tagged MRI is linearly correlated to left ventricular ejection fraction obtained by standard cardiac cine MRI (y=1.0x+1.31, r>0.98, p=0.014). In addition, the inter-observer and intra-observer coefficient of variation for left ventricular ejection fraction measurements was low (CV_intra=0.4%, CV_inter=1.3%). With tagged MRI, only end-systolic volume needs to be manually determined, and accurate estimation of left ventricular ejection fraction is obtained because end-diastolic and end-systolic volumes are determined using identical anatomical points. Our data indicate that tagged MRI can be used to quantitatively assess both regional and global left ventricular function. Therefore, tagged MRI may be a valuable clinical tool for determining the prognosis and evaluating the effect of therapeutical intervention using a single imaging session in patients with left ventricular dysfunction.     

64层螺旋CT与1.5 T MRI在慢性阻塞性肺病患者右心功能测定中的临床应用

分别与第1秒用力呼气容积有很好的相关性(rRVEF=0.781,rMM=-0.824).结论 重度COPD患者有严重右心功能损伤,与MRI结果比较,MSCT心功能检查可以正确定量评价右心室容积和功能.     

Diffusion‐weighted hyperpolarized 129Xe MRI in healthy volunteers and subjects with chronic obstructive pulmonary disease

Given its greater availability and lower cost, ¹²⁹Xe apparent diffusion coefficient (ADC) MRI offers an alternative to ³He ADC MRI. To demonstrate the feasibility of hyperpolarized ¹²⁹Xe ADC MRI, we present results from healthy volunteers (HV), chronic obstructive pulmonary disease (COPD) subjects, and age‐matched healthy controls (AMC). The mean parenchymal ADC was 0.036 ± 0.003 cm² sec^?1 for HV, 0.043 ± 0.006 cm² sec^?1 for AMC, and 0.056 ± 0.008 cm² sec^?1 for COPD subjects with emphysema. In healthy individuals, but not the COPD group, ADC decreased significantly in the anterior–posterior direction by ～22% (P = 0.006, AMC; 0.0059, HV), likely because of gravity‐induced tissue compression. The COPD group exhibited a significantly larger superior–inferior ADC reduction (～28%) than the healthy groups (～24%) (P = 0.00018, HV; P = 3.45 × 10^?5, AMC), consistent with smoking‐related tissue destruction in the superior lung. Superior–inferior gradients in healthy subjects may result from regional differences in xenon concentration. ADC was significantly correlated with pulmonary function tests (forced expiratory volume in 1 sec, r = ?0.77, P = 0.0002; forced expiratory volume in 1 sec/forced vital capacity, r = ?0.77, P = 0.0002; diffusing capacity of carbon monoxide in the lung/alveolar volume (V_A), r = ?0.77, P = 0.0002). In healthy groups, ADC increased with age by 0.0002 cm² sec^?1 year^?1 (r = 0.56, P = 0.02). This study shows that ¹²⁹Xe ADC MRI is clinically feasible, sufficiently sensitive to distinguish HV from subjects with emphysema, and detects age‐ and posture‐dependent changes. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.     

MRI of the lungs in children

Lung diseases of children often need diagnostic imaging beyond X-ray. Although CT is considered the gold standard of lung imaging, MRI is sufficient to answer most of the questions raised. After all, the exposure to radiation caused by one CT examination corresponds to approximately the effective dose of 200 chest radiographs.     

低剂量CT扫描及肺功能检查对COPD小气道参数的研究

目的 探讨低剂量CT扫描和肺功能检查在评价COPD患者气道重塑方面的作用和关系.方法 选取COPD患者60例为观察组,同时选择与观察组患者年龄匹配的健康体检者30例为对照组.应用低剂量CT扫描并观察患者肺部影像学表现,运用后处理软件测量COPD患者气道壁厚度(T)、气道壁面积(WA)及气道外径(D)等参数,评估气道重塑...     

超声心动图评估稳定期慢性阻塞性肺疾病患者右心功能的价值

目的 :应用美国超声心动图学会推荐的右心功能超声指标评估稳定期慢性阻塞性肺疾病的右心功能,并寻找一个可靠敏感指标运用于常规检查中。方法:64例轻中度慢性阻塞性肺疾病患者,按照严重程度分为肺功能Ⅱ级29例,Ⅲ级35例;另选择33例同期健康体检者作为对照组,3组无年龄及性别差异。测量3组19项指标,探讨慢性阻塞性肺疾病Ⅱ级、Ⅲ级同健康成人之间的差异性。结果:右室流出道(RVOT)近端内径对照组(29.08±2.12)mm,肺功能Ⅱ级(31.04±2.95)mm,Ⅲ级(32.00±3.45)mm,对照组与肺功能Ⅱ、Ⅲ级比较差异均有统计学意义(均P0.05);右室基底径对照组(31.15±4.83)mm,肺功能Ⅱ级(33.86±3.75)mm,Ⅲ级(34.06±4.41)mm,对照组与肺功能Ⅱ、Ⅲ级比较差异均有统计学意义(均P0.05);右室壁厚度对照组(4.53±0.50)mm,肺功能Ⅱ级(5.15±1.07)mm,Ⅲ级(5.27±0.91)mm,对照组与肺功能Ⅱ、Ⅲ级比较差异均有统计学意义(均P0.05);下腔静脉塌陷率对照组(56.23±4.23)%,肺功能Ⅱ级(31.51±10.13)%,Ⅲ级(28.25±11.01)%,对照组与肺功能Ⅱ、Ⅲ级比较差异均有统计学意义(均P0.05);组织多普勒三尖瓣侧壁部瓣环收缩期峰值流速(S’)对照组(10.74±1.08)cm·s-1,肺功能Ⅱ级(9.62±1.37)cm·s-1,Ⅲ级(9.24±0.91)cm·s-1,对照组与肺功能Ⅱ、Ⅲ级比较差异均有统计学意义(均P0.05);3组间E/A、Tei指数差异均有统计学意义(对照组1.53±0.25、肺功能Ⅱ级0.93±0.28、Ⅲ级0.65±0.20;对照组0.46±0.14、肺功能Ⅱ级0.54±0.87、Ⅲ级0.63±0.14;均P0.05)。结论 :随着肺功能的恶化,右心功能减低,Tei指数和S’能够较敏感地反映右心功能。     

速度向量成像技术评估猪右室压力负荷对左室短轴收缩同步性的影响

目的应用速度向量成像(velocity vector imaging,VVI)技术探讨右室压力负荷对左室短轴收缩同步性的影响。方法 6只开胸实验猪,采用肺动脉环缩术成功制备肺动脉狭窄模型。分别于基础状态,术后1个月后,采集胸骨旁左心室短轴乳头肌水平连续3个心动周期的二维灰阶图像,应用VVI技术分别测量胸骨旁短轴观收缩期径向速度达峰时间(Tvr)、环向应变达峰时间(Tsc)、计算节段达峰时间的标准差(Tvr-SD,Tsc-SD)及任意两节段间最大达峰时间差值(Tvr-diff,Tsc-diff)。同时采用经胸超声心动图计算左室射血分数(LVEF)。分别进行各参数间比较。结果与基础状态比较,左室心肌收缩不同步指标Tvr-SD,Tsc-SD及Tvr-diff,Tsc-diff均显著增加(P<0.05)。左室射血分数(LVEF)较基础状态相比无显著性差异(P>0.05)。结论右室压力过负荷时左室心肌在径向与环向上均存在显著的收缩不同步。     

Comparison of the reproducibility of quantitative cardiac left ventricular assessments in healthy volunteers using different MRI scanners: a multicenter simulation

PURPOSE: To derive reproducibility assessments of ejection fraction (EF) and left ventricular mass (LVM) from short-axis cardiac MR images acquired at single and multiple time-points on different 1.5T scanner models. MATERIALS AND METHODS: Images of 15 healthy volunteers were acquired twice using a Magnetom Avanto scanner (Siemens, Erlangen, Germany) and once using a Signa Excite scanner (General Electric, Milwaukee, WI, USA) over four months, and analyzed using ARGUS and MASS Analysis+ software, respectively. Two physicists independently segmented the myocardial borders in order to derive intra- and interobserver assessments of EF and LVM for single and multiple time-points on the same and different scanners. RESULTS: For EF, the coefficient of repeatability (CoR) increased as different observers, multiple time-points, and different scanners were introduced. The CoR ranged from 2.8% (intraobserver measurements, single time-point, same scanner) to 10.0% (interobserver measurements, different time-points, different scanners). For LVM, intraobserver CoR parameters were consistently smaller than interobserver values. The CoR ranged from 7.8 g (intraobserver measurements, single time-point, same scanner) to 39.5 g (interobserver measurements, different time-points, different scanners). CONCLUSION: Reproducible EF data can be obtained at single or multiple time-points using different scanners. However, LVM is notably susceptible to interobserver variation, and this should be carefully considered if similar evaluations are planned as part of multicenter or longitudinal investigations.