FAIR肺实质MRI灌注成像的可行性研究

目的探讨FAIR在肺实质MRI灌注成像中的可行性。方法用GE 1.5T Excite HD磁共振成像系统(GE Healthcare,Milwaukee)对20例健康志愿者,结合心电门控技术在心脏舒张中期、呼气末屏气状态下行冠状面FAIR扫描。分别计算每个志愿者不同层面右肺与左肺的灌注值(PBF)并计算其比值(PBFR/PBFL,R/L)。结果20例志愿者均能较好的配合检查。在2个不同冠状面均获得SNR较高的灌注图像,左、右两肺的灌注相对较均匀。①经胸主动脉中央层面:右肺灌注为86.83±23.91,左肺灌注为86.86±27.44;左、右两肺灌注无明显统计学差异(P=0.9806>0.05);R/L为1.0103±0.0395。②经肺门层面:右肺灌注为40.86±14.56,左肺灌注为74.35±24.99;左、右两肺灌注有明显统计学差异(P=0.0001<0.05);R/L为0.5470±0.0477。③2个不同层面R/L的差异为(45.84±5.39)%。结论FAIR用于MRI肺灌注成像是可行的,由于质子饱和效应的因素,在个别层面左、右肺的灌注有差异。     

重力对FAIR序列肺灌注成像影响的研究

目的 用FAIR序列评价重力对MRI肺灌注血流分布的影响.资料与方法 对10例健康志愿者在仰卧位时,分别对5个冠状面FAIR图像的肺血流量(PBF)间进行分析.结果 在重力方向上存在灌注梯度,5个冠状面的PBF间的差异均有统计学意义(P<0.05),PBF由后至前是逐渐减小的.在非重力方向上,肺灌注不存在灌注梯度.右肺的回归系数是-4.98,左肺的回归系数是-5.16.结论 FAIR评价肺灌注在重力方向的灌注梯度是比较敏感的,可提高灌注缺损的检出率.     

5岁以下儿童呼吸双相肺密度的CT测量

目的 采用CT测量5岁以下儿童呼气末、吸气末肺组织的平均密度值.方法 选取2010年1月至2012年3月在我院因外伤等疾病进行胸部CT扫描的正常肺患儿60例.通过随机数字表法分为吸气末扫描组与呼气末扫描组进行通气控制CT扫描,每组30例.获取胸部吸气末、呼气末CT图像.胸部CT图像中选取主动脉弓上2 cm、隆突下1 cm、膈上2cm3个层面肺组织的腹侧、背侧、外侧、内侧、中心测量肺CT值.计算左肺、右肺以及全肺的平均密度值.对单侧肺吸气末、呼气末各测量区域肺密度值的变化采用单因素方差分析,各测量区域间肺密度值变化两两比较采用LSD法.结果 吸气末左肺、右肺及全肺对应的肺密度值均为(-766±56)HU,呼气末相应的值分别为(-625±86)、(-647±85)、(-636±86)HU.吸气末,左肺腹侧、背侧、外侧、内侧、中心肺密度值分别为(-798±63)、(-733±68)、(-767±64)、(-754±65)、(-775±63)HU,右肺分别为(-796±70)、(-736±65)、(-769±64)、(-754±62)、(-776±59)HU;呼气末,左肺上述5个部位肺密度值分别为(-692±91)、(-555±116)、(-639±91)、(-598±103)、(-640±98)HU,右肺分别为(-712±90)、(-575±121)、(-657±90)、(-619±95)、(-670±87)HU,双肺5个测量部位在吸气末和呼气末肺密度值差异均有统计学意义(F值分别为12.55、11.29、23.31、25.47,P值均＜0.01).5个测量部位中,背侧肺密度平均值最高,腹侧最低,其余从高到低分别为内侧、外侧、中心.结论 本研究测量得到5岁以下儿童呼气末、吸气末肺组织的密度值,可为临床工作提供参考.     

多层螺旋CT肺功能成像在评价石棉沉着病病人肺功能的应用研究

目的应用多层螺旋CT(MSCT)肺功能成像技术评价石棉沉着病病人在疾病不同分期中肺功能指标的变化及特点。方法选取2013年1月1日—2015年12月31日间明确诊断的石棉沉着病病人21例及正常对照组21例,同时收集受检者年龄、性别、接触史、工种等基本信息。对每位受检者分别在深吸气末和深呼气末屏气行全肺扫描,采用Siemens Pulmo肺定量分析软件对CT肺容积、密度指标进行测定。采用独立样本t检验对石棉沉着病组与对照组的肺容积指标和平均肺密度指标进行比较,采用LSD-t检验对石棉沉着病不同分期组与对照组间各项肺功能指标进行多重比较,并分别采用秩和检验和Fisher确切概率检验对石棉沉着病不同分期组间的粉尘接触史和工种类型进行比较。结果 1石棉沉着病Ⅰ期组与Ⅱ期组在职业接触史时间上差异有统计学意义(Z=5.023,P0.05),并且随着职业接触史时间的延长,Ⅱ期病人的出现概率增高;而两组病人在不同工种之间差异无统计学意义(P0.05)。2石棉沉着病组吸气相肺容积(V_(in))、左肺V_(in)(LV_(in))、右肺V_(in)(RV_(in))、吸气相和呼气相的肺容积差(V_(in)-V_(ex))均较对照组减小;右肺呼气相肺容积(RV_(ex))、呼气相和吸气相的肺容积比(V_(ex)/V_(in))较对照组增大(均P0.05);而两组间V_(ex)和LV_(ex)差异无统计学意义(均P0.05)。3两组间吸气相平均肺密度(MLD_(in))、吸气相左肺平均肺密度(LMLD_(in))和吸气相右肺平均肺密度(RMLD_(in))差异无统计学意义(均P0.05)。石棉沉着病组呼气相平均肺密度(MLD_(ex))、呼气相左肺平均肺密度(LMLD_(ex))、呼气相右肺平均肺密度(RMLD_(ex))、呼气相和吸气相的平均肺密度比(MLD_(ex)/MLD_(in))均较对照组增大,而呼气相和吸气相的平均肺密度差(MLD_(ex)-MLD_(in))较对照组减小,其差异均有统计学意义(均P0.05)。4石棉沉着病Ⅱ期组较Ⅰ期组和对照组的RV_(ex)均增大;石棉沉着病Ⅰ期组和Ⅱ期组的V_(in)-V_(ex)均较对照组减小,且Ⅱ期组的V_(in)-V_(ex)低于Ⅰ期组(均P0.05);3组间其余肺容积指标和CT平均肺密度各项指标差异均无统计学意义(均P0.05)。结论石棉沉着病病人肺功能改变的特点为肺总量、左肺和右肺总量减低,双肺残气量、左肺和右肺残气量升高,用力肺活量降低,肺气肿形成,而且石棉沉着病病人的粉尘接触时间越长其病情越严重。多层螺旋CT肺功能成像技术在评价石棉沉着病病人肺功能方面具有重要作用。     

64排螺旋 CT 及三维容积测量系统对肺叶容积的定量研究

目的：探讨64排螺旋C T及三维容积测量系统对肺叶容积定量分析的价值。方法选取正常健康志愿者77例,采用64排螺旋C T于深吸气末和深呼气末分别扫描全肺,用三维容积测量系统半自动提取并测量右肺上叶,右肺中叶,右肺下叶,左肺上叶及下叶深吸气末及深呼气末各肺叶及全肺容积。结果男性吸气末和呼气末左肺上叶、右肺下叶、左肺下叶、右肺上叶、右肺中叶容积分别为1303．90mL和938．31mL、1276．90mL和737．69mL、1204．47mL和678．67mL、1048．49mL和754．83mL、519．53mL和407．86mL ;女性吸气末和呼气末左肺上叶、右肺下叶、左肺下叶、右肺上叶、右肺中叶容积分别为915．78mL和666．23mL、913．87mL和576．62mL、822．17mL和509．30mL、734．20mL和530．23mL、389．13mL和316．70mL ;同性别比较各叶肺容积在吸气末及呼气末均有显著性差异（P＜0．05）。男性与女性比较,两肺各叶吸气末与呼气末肺叶容积均有显著性差异（P＜0．05）。在男性及女性组吸气末与呼气末各肺叶容积之差值比较中,均为双肺下叶容积差值最大,其次为左肺上叶,右肺上叶及右肺中叶,说明双肺下叶在肺活量中权重最大。男性各肺叶肺容积差值显著大于女性（P＜0．05）。结论64排螺旋CT及三维容积测量系统能够对肺叶的形态及容积进行准确的定量评估。     

呼气相肺部高分辨力CT扫描的临床应用研究

目的:探讨在不增加放射剂量的情况下HRCT呼气相肺容积测定,对存在小气道异常的弥散性肺疾病的临床应用价值。方法:45例研究对象行吸气末和呼气末屏气HRCT全肺扫描(层厚1.25mm,间隔20mm,骨算法)并进行冠状面图像重组,测定肺容积。结果:45例患者呼气相HRCT表现为支气管扩张、气管及支气管软化、全小叶型肺气肿、空气潴留等。呼气相HRCT对与空气潴留区相通的气道显示率达100%,冠状面重组图像对空气潴留的范围和分布所提供的诊断信息达到90%,与吸气相HRCT相比,差异均有极显著性意义(P<0.0001)。结论:在不增加患者有效的照射剂量或不降低图像质量的情况下,HRCT呼气相肺容积测定技术可以获得容积数据对显示气道病变及空气潴留区域的范围和分布有重要价值。     

SPECT/CT肺灌注显像中肺段精确定位方法的研究

目的 研究SPECT/CT肺灌注显像中肺段横断面、矢状面及冠状面的精确定位方法.方法 分析12名健康成人的肺灌注断层图像、CT图像及二者的融合图像,按CT解剖命名标准对肺灌注横断面、矢状面及冠状面图像上肺段进行划分.即右肺10段:上叶尖段、后段、前段,中叶外侧段、内侧段,下叶背段、内基底段、前基底段、外基底段、后基底段;左肺8段:上叶尖后段、前段、上舌段、下舌段,下叶背段、前内基底段、外基底段、后基底段,并总结3个层面肺段分布的特点.结果 确定了左右肺在横断面、矢状面及冠状面上的典型层面及各个肺段的主要分布特点:(1)横断面双肺由肺尖至肺底选取11个层面:胸锁关节层面及以上,主动脉弓上缘层面,主动脉弓层面,奇静脉弓层面或气管杈层面,右肺上叶支气管层面或左肺动脉层面,左肺上叶支气管层面或右肺动脉层面,中叶或舌叶支气管层面,底干支气管层面,下肺静脉层面,上下底段静脉层面,底段静脉层面;(2)双肺由内向外分别选取6个层面,左肺:左肺门层面,左主支气管杈层面,左肺动脉叶间部层面,心尖层面,心尖左侧第一层面,心尖左侧第二层面;右肺:右肺门层面,中间支气管杈层面,叶间动脉层面,叶间动脉分杈层面或右心房右侧第一层面,右心房右侧第二层面,右心房右侧第三层面向外;(3)冠状面双肺由前向后选取7个层面:胸锁关节层面,升主动脉层面,肺动脉杈层面,气管杈层面,中间支气管层面,底段总静脉层面,胸主动脉层面.结论 按该研究方法划分肺段,可为肺灌注断层图像中肺段的精确定位提供参考依据.     

SPECT/CT肺灌注显像中肺段精确定位方法的研究

目的 研究SPECT/CT肺灌注显像中肺段横断面、矢状面及冠状面的精确定位方法.方法 分析12名健康成人的肺灌注断层图像、CT图像及二者的融合图像,按CT解剖命名标准对肺灌注横断面、矢状面及冠状面图像上肺段进行划分.即右肺10段:上叶尖段、后段、前段,中叶外侧段、内侧段,下叶背段、内基底段、前基底段、外基底段、后基底段;左肺8段:上叶尖后段、前段、上舌段、下舌段,下叶背段、前内基底段、外基底段、后基底段,并总结3个层面肺段分布的特点.结果 确定了左右肺在横断面、矢状面及冠状面上的典型层面及各个肺段的主要分布特点:(1)横断面双肺由肺尖至肺底选取11个层面:胸锁关节层面及以上,主动脉弓上缘层面,主动脉弓层面,奇静脉弓层面或气管杈层面,右肺上叶支气管层面或左肺动脉层面,左肺上叶支气管层面或右肺动脉层面,中叶或舌叶支气管层面,底干支气管层面,下肺静脉层面,上下底段静脉层面,底段静脉层面;(2)双肺由内向外分别选取6个层面,左肺:左肺门层面,左主支气管杈层面,左肺动脉叶间部层面,心尖层面,心尖左侧第一层面,心尖左侧第二层面;右肺:右肺门层面,中间支气管杈层面,叶间动脉层面,叶间动脉分杈层面或右心房右侧第一层面,右心房右侧第二层面,右心房右侧第三层面向外;(3)冠状面双肺由前向后选取7个层面:胸锁关节层面,升主动脉层面,肺动脉杈层面,气管杈层面,中间支气管层面,底段总静脉层面,胸主动脉层面.结论 按该研究方法划分肺段,可为肺灌注断层图像中肺段的精确定位提供参考依据.     

SPECT/CT肺灌注显像中肺段精确定位方法的研究

目的 研究SPECT/CT肺灌注显像中肺段横断面、矢状面及冠状面的精确定位方法.方法 分析12名健康成人的肺灌注断层图像、CT图像及二者的融合图像,按CT解剖命名标准对肺灌注横断面、矢状面及冠状面图像上肺段进行划分.即右肺10段：上叶尖段、后段、前段,中叶外侧段、内侧段,下叶背段、内基底段、前基底段、外基底段、后基底段 左肺8段：上叶尖后段、前段、上舌段、下舌段,下叶背段、前内基底段、外基底段、后基底段,并总结3个层面肺段分布的特点.结果 确定了左右肺在横断面、矢状面及冠状面上的典型层面及各个肺段的主要分布特点：（1）横断面双肺由肺尖至肺底选取11个层面：胸锁关节层面及以上,主动脉弓上缘层面,主动脉弓层面,奇静脉弓层面或气管杈层面,右肺上叶支气管层面或左肺动脉层面,左肺上叶支气管层面或右肺动脉层面,中叶或舌叶支气管层面,底干支气管层面,下肺静脉层面,上下底段静脉层面,底段静脉层面 （2）双肺由内向外分别选取6个层面,左肺：左肺门层面,左主支气管杈层面,左肺动脉叶间部层面,心尖层面,心尖左侧第一层面,心尖左侧第二层面 右肺：右肺门层面,中间支气管杈层面,叶间动脉层面,叶间动脉分杈层面或右心房右侧第一层面,右心房右侧第二层面,右心房右侧第三层面向外 （3）冠状面双肺由前向后选取7个层面：胸锁关节层面,升主动脉层面,肺动脉杈层面,气管杈层面,中间支气管层面,底段总静脉层面,胸主动脉层面.结论 按该研究方法划分肺段,可为肺灌注断层图像中肺段的精确定位提供参考依据.     

呼吸针控用于CT引导下经皮经肺穿刺近膈肝肿瘤

近膈肝肿瘤解剖位置特殊,受呼吸影响活动度大,CT引导下行经皮经肺穿刺活检或微波消融术时容易发生气胸[1],往往只有1次穿刺机会.如何有效控制患者呼吸是CT引导下经皮经肺穿刺近膈肝肿瘤成功的重要因素.虽然有学者报道[2]在对近膈肝肿瘤行CT引导下经皮经肺穿刺,训练患者呼吸使定位和穿刺始终在同一呼吸相,如在吸气末、呼气末或平静呼吸屏气,这些方法对克服呼吸影响有一定的积极作用,但患者由于受到疼痛或紧张等因素影响,很难做到每次呼吸同相.本研究采用呼吸针控法,有效地做到了定位和穿刺时呼吸同相.现报道如下.     

Demonstration of pulmonary perfusion heterogeneity induced by gravity and lung inflation using arterial spin labeling

Objective

To evaluate the effect of gravity and lung inflation on pulmonary perfusion heterogeneity in human lung using an arterial spin labeling (ASL) sequence called flow sensitive alternating inversion recovery (FAIR).

Materials and methods

Magnetic resonance imaging of lung perfusion using arterial spin labeling sequence was performed in supine position in ten healthy volunteers on a 1.5 T whole body scanner (GE Healthcare). Five coronal slices at an interval of 3 cm from dorsal to ventral (labeled as P3, P6, P9, P12, P15, sequently) were obtained when the volunteers performed breath holding on end expiration and the relative pulmonary blood flow (rPBF) was measured. Then, another coronal perfusion-weighted image of P3 slice was obtained on end inspiration. Tagging efficiency of pulmonary parenchyma with IR (ΔSI), rPBF and area of the P3 slice were analyzed.

Results

(1) Along the direction of gravity, a gradient was visually perceived as a vertical increase in rPBF. There were significant statistic differences in rPBF between any two coronal planes except that between P12 and P15. In supine position, regression coefficients of right and left lung were −4.98 and −5.16, respectively. This means that rPBF decreased 4.98 (right) and 5.16 (left) for each centimeter above the dorsal. No statistical difference was seen between ROIs placed along iso-gravitational plane. (2) For a same slice, there were significant statistic differences in ΔSI, rPBF and area at different respiratory phases (P < 0.05). Greater ΔSI and more perfusion were observed on end expiration than on end inspiration. The area was larger on end inspiration than on end expiration.

Conclusion

Both gravity and respiratory phase are important determinants of pulmonary perfusion heterogeneity. FAIR is sensitive to demonstrate gravity- and respiratory phase-dependent differences in lung perfusion. Positioning the patient so that the area of interest is down-gravity and asking patient to hold breath on end expiration may help in detection of perfusion defects.     

Comparison of arterial spin labeling and first-pass dynamic contrast-enhanced MR imaging in the assessment of pulmonary perfusion in humans: the inflow spin-tracer saturation effect.

The flow-sensitive alternating inversion recovery (FAIR) and the first-pass dynamic contrast-enhanced MR imaging (CE-MRI) techniques have both been shown to be effective in the assessment of human pulmonary perfusion. However, no comprehensive comparison of the measurements by these two methods has been reported. In this study, healthy adults were recruited, with FAIR and CE-MRI performed for an estimation of the relative pulmonary blood flow (rPBF). Regions of interest were encircled from the right and left lungs, with right-to-left rPBF ratios calculated. Results indicated that, on posterior coronal slices, the rPBF ratios obtained with the FAIR technique agreed well with CE-MRI measurements (mean difference = -0.02, intraclass correlation coefficient RI = 0.78, 95% confidence interval = [0.67, 0.86]). On middle coronal slices, however, FAIR showed a substantially lower rPBF by up to 43% in the right lung compared with CE-MRI (mean difference = -0.38, RI = 0.34, 95% confidence interval = [-0.09, 0.68]). The location-dependent discrepancy between measurements by FAIR and CE-MRI methods is attributed to tracer saturation effects of arterial inflow when the middle coronal slice contains the in-plane-oriented right pulmonary artery, whereas the left lung rPBF is less affected due to oblique orientation of the left pulmonary artery. Intrasequence comparison on additional subjects using FAIR at different slice orientations supported the above hypothesis. It is concluded that FAIR imaging for pulmonary perfusion in the coronal plane provides equivalent rPBF information with CE-MRI only in the absence of tracer saturation effects; hence, FAIR should be carefully exercised to avoid misleading interpretations.     

Effect of respiratory phases on MR lung signal intensity and lung conspicuity using segmented multiple inversion recovery turbo spin echo (MIR-TSE).

The purpose of this study was to determine the effect of respiratory phase on signal intensity of the lung. Lung images were obtained from eleven healthy human volunteers using a multiple inversion recovery segmented turbo spin echo sequence (MIR-TSE). MIR exploits the difference in T(1) between different tissues to effectively null signal contributions from fat and muscle for improved visualization of the lung. The volunteers were asked to perform breath-holding on end inspiration or end expiration. There was a significant decrease in signal intensity of the lung with average SNR of 7.3 +/- 0.9 vs. 14.4 +/- 0.8 for coronal slices, and 9.5 +/-1.5 vs. 16.0 +/-2.4 for sagittal breath-hold images acquired during end inspiration compared with end expiration. It is concluded that MRI of the lungs should be performed during end expiration in order to optimize image quality.     

Quantitative lung perfusion mapping at 0.2 T using FAIR True-FISP MRI.

Perfusion measurements in lung tissue using arterial spin labeling (ASL) techniques are hampered by strong microscopic field gradients induced by susceptibility differences between the alveolar air and the lung parenchyma. A true fast imaging with steady precession (True-FISP) sequence was adapted for applications in flow-sensitive alternating inversion recovery (FAIR) lung perfusion imaging at 0.2 Tesla and 1.5 Tesla. Conditions of microscopic static field distribution were assessed in four healthy volunteers at both field strengths using multiecho gradient-echo sequences. The full width at half maximum (FWHM) values of the frequency distribution for 180-277 Hz at 1.5 Tesla were more than threefold higher compared to 39-109 Hz at 0.2 Tesla. The influence of microscopic field inhomogeneities on the True-FISP signal yield was simulated numerically. Conditions allowed for the development of a FAIR True-FISP sequence for lung perfusion measurement at 0.2 Tesla, whereas at 1.5 Tesla microscopic field inhomogeneities appeared too distinct. Perfusion measurements of lung tissue were performed on eight healthy volunteers and two patients at 0.2 Tesla using the optimized FAIR True-FISP sequence. The average perfusion rates in peripheral lung regions in transverse, sagittal, and coronal slices of the left/right lung were 418/400, 398/416, and 370/368 ml/100 g/min, respectively. This work suggests that FAIR True-FISP sequences can be considered appropriate for noninvasive lung perfusion examinations at low field strength.     

Pulmonary perfusion assessment with respiratory gated 99mTc macroaggregated albumin SPECT: preliminary results

PURPOSE: Respiratory gated perfusion single photon emission computed tomography (SPECT) was applied to reduce respiratory lung motion effects and to reliably assess perfusion impairment in various lung diseases. METHODS: After injection of 259 MBq of 99mTc macroaggretated albumin (99mTc-MAA), gating was performed using a triple-headed SPECT unit connected to a physiological synchronizer in a total of 35 patients with either obstructive lung diseases (n = 14), pulmonary embolism (n = 8), small lung nodules (n = 7) or acute interstitial pneumonia (n = 6). Projection data were acquired in a 64 x 64 matrix, with 20 stops over 120 degrees for each detector with a preset time of 15 s for each stop. Inadequate data for the respiratory cycle were automatically eliminated. In addition to end inspiration images and end expiration images derived from 12.5% threshold data centred at peak inspiration and expiration for each respiratory cycle, respectively, an ungated image was obtained from full respiratory cycle data. RESULTS: Gated images were completed for 13.7 +/- 1.8 min in all subjects. Although the total lung radioactivity of the gated images were reduced to approximately 13% of that of the ungated images, these gated images showed uniform perfusion in the unaffected lungs and visualized a total of 94 (21.9%) additional perfusion defects against 429 defects visualized on ungated images in 31 patients with focal perfusion defects. Among the perfusion defects visualized on both gated images, the defect size was occasionally larger on the end inspiration images. The end expiration images showed significantly higher lesion-to-normal lung radioactivity ratios compared with those on the end expiration and ungated images in the affected lower lungs throughout the lung diseases. Radioactivity changes per pixel between end inspiration and end expiration images in the affected lower lungs of the obstructive lung diseases were significantly lower compared with those of pulmonary embolism and acute interstitial pneumonia (P<0.0001 and P<0.01, respectively). CONCLUSION: This technique appears to enhance the clarity of perfusion defects, and lung radioactivity changes between end inspiration and end expiration may characterize regionally impaired ventilation status.     

T1 mapping of the entire lung parenchyma: Influence of respiratory phase and correlation to lung function test results in patients with diffuse lung disease.

The T(1) values of lung parenchyma of 25 patients with fibrosis and emphysema were measured in the entire lung, and the effect of inspiration and expiration was investigated. T(1) map acquisition was based on a snapshot-fast low-angle shot (FLASH) sequence. Lung function and blood gas tests were measured. The study documents reverse respiratory phase dependence of T(1) measurements of the entire lung parenchyma in patients with emphysema and fibrosis. Furthermore, expiratory measurements showed higher and reverse differences between patient groups compared to inspiratory measurements. For the emphysema group, the average T(1) value in inspiration was 1033 +/- 74 ms. The average of the mean T(1) values in expiration was 982 +/- 56 ms. For the patients with fibrosis, the average T(1) value in inspiration was 996 +/- 103 ms. Compared to that, the average T(1) value in expiration was 1282 +/- 170 ms. Linear regression of T(1) vs. lung function parameters showed the highest regression coefficients for total lung capacity (TLC) and residual volume (RV) in expiration, the values were inversely proportionally dependent on the pooled expiratory T(1) values. These findings underline the strong but nonuniform influence of the inspirational status during T(1) measurements of the lung. T(1) maps in both emphysema and fibrosis should preferably be acquired at expiration if reliable data are to be obtained.     

放射性核素显像及心血管造影对Fontan术后肺血流灌注的随访

目的通过放射性核素显像和心血管造影,观察心外全腔静脉一肺动脉连接（ETCPC）手术后完全旷置右心对肺血流灌注的长期影响。方法回顾性分析1990年3月至2005年12月间行ETCPC手术的53例[男29例,女24例,平均年龄（10．8±6．1）岁]患者资料。其中43例随访资料完整的患者均于术后1个月内（早期）及5年（中期）随访时行”1rcmIMAA肺灌注显像和心血管造影检查,并分别计算各肺段灌注比值、PVR及肺动脉指数。采用配对t检验分析患者早、中期的肺血流分布变化。结果”TcmMAA肺灌注显像结果示,中期随访与早期随访患者的肺总放射性计数值差异无统计学意义[（701．91±8．26）×10^3计数／s和（698．93±12．0）×103计数／s;t=0．38,P〉0．05],右肺／左肺灌注比值（1．06±0．01和1．03±0．03;t=1．12,P〉0．05）及下腔静脉右肺灌注比值（0．61±0．06和0．60±0．06;t=0．74,P〉0．05）无有意义的改变,全肺上段／下段比值下降（0．72±0．20和0．75±0．01;t=2．54,P〈0．05）,肺下叶背段灌注比例升高（0．12±0．00和0．10±0．03;t=2．16,P〈0．05）。中期随访患者的PVR下降[（142．98±2．61）dyn·s·cm-5（1dyn·S·cm-5=0．1kPa·S·L-1）和（146．95±2．54）dyn·s·cm-5;t=2．08,P〈0．05],腔静脉压下降[（9．35±0．24）mmHg（1mmHg：0．133kPa）和（9．95±0．23）mmHg;t=2．69,P〈0．05],动脉血氧饱和度未见明显改变[（92．70±0．30）％和（92．86±0．29）％;t=1.12,P〉0．05]。5例患者术后早期存在肺动脉造影与核素显像明显不匹配。结论在研究功能性肺血流灌注方面,放射性核素显像效果优于心血管造影。Fontan循环的长期弱动力、无搏动血流会引起肺血流坠积性重新分布。     

Effect of lung inflation on arterial spin labeling signal in MR perfusion imaging of human lung

The effect of lung inflation on arterial spin-labeling signal in lung perfusion is investigated. Arterial spin-labeling schemes, called alternation of selective inversion pulse (ASI) and its hybrid (HASI), which uses blood water as an endogenous, freely diffusible tracer, were applied to magnetic resonance (MR) perfusion imaging of the lung. Perfusion-weighted images of the lung from nine healthy volunteers were obtained at different time delays. There was a significant signal difference in ASI images acquired at different respiratory phases. Greater signal enhancement has been observed when the volunteers performed breath holding on end expiration than on end inspiration. This is in agreement with the normal physiologic effect of lung inflation on the pressure-flow relationship of pulmonary vasculature. ASI and HASI perfusion-weighted images show similar lung features and image quality. Preliminary results from pulmonary embolism patients indicate that arterial spin labeling is sensitive for the detection of areas of perfusion deficit. J. Magn. Reson. Imaging 2001;13:954-959.     

肺灌注显像定量分析评价特发性肺动脉高压

目的探讨肺灌注显像肺血流灌注分布指数（简称P指数）定量分析法评价特发性肺动脉高压（IPAH）的应用价值。方法选取30例临床确诊的IPAH患者,行肺灌注显像和右心导管检查。应用美国国立卫生研究院开发的开源软件NIHImage进行P指数定量分析,同时选取12名年龄相匹配的健康对照者进行肺灌注显像,以得到灌注面积百分比标准曲线,并对全部30例患者的P指数和血流动力学参数进行Pearson相关性分析。按肺灌注显像特点将患者分为3组（双肺放射性分布均匀;双肺放射性分布不均匀,肺尖部放射性浓聚;双肺放射性分布明显不均匀,呈“斑片状”稀疏和缺损改变）,比较各组间P指数的差异。采用SPSS11．0软件,组间比较行student’st检验。结果P指数与平均肺动脉压（mPAP）及全肺阻力（TPR）呈直线相关性,P指数与mPAP的相关系数为0．541（P〈0．01）,与TPR的相关系数为0．573（P〈0．01）。图像定性分析3种特征性图像的P指数分别为9．47±1．06,13．77±4．57和18．97±5．93,呈递增趋势（t值分别为-2．83,-5．68和-2．65,P均〈0．05）;mPAP、TPR亦依次呈递增趋势,但差异无统计学意义（t=-1．990～0．236,P均〉0．05）。结论肺灌注显像P指数定量分析法能够准确反映肺动脉压力和TPR等血流动力学状态,对IPAH的诊断和疗效判断具有较好的应用前景。