微创非切除法肺减容术的研究进展

微创治疗是肺减容术(LVRS)治疗重度肺气肿的发展方向,随着新方法和新器械的不断出现及改进,这种治疗将成为重度肺气肿病人的另一个重要选择。该文回顾了目前肺气肿治疗的概况,就微创肺减容术的方法、器械以及初步研究成果和最新进展等进行了综述。     

Preliminary application of dynamic pulmonary xenon-133 single-photon emission tomography in the evaluation of patients with pulmonary emphysema for thoracoscopic lung volume reduction surgery

Dynamic pulmonary xenon-133 single-photon emission tomography (SPET) with three-dimensional (3D) displays was preliminarily applied to select resection targets for thoracoscopic lung volume reduction surgery (LVRS) and to assess regional ventilatory changes following surgery. Dynamic SPET was performed using a triple-detector SPET system in 14 patients with pulmonary emphysema before and after LVRS. After reconstructing colour-illuminated, surface-rendered 3D images of equilibrium (EQ) and 3-min washout (WO₃), a single 3D fusion display was created from these two different time-course image sets, in which the 3D WO₃ image indicating ¹³³Xe retention was visible through the overlying 3D EQ image delineating lung contours. Volumetric extent of retention on this display was quantified by a ¹³³Xe retention index, defined as the ratio (%) of total pixel numbers of segmented 3-min WO data to those of EQ data. ¹³³Xe SPET and appropriately thresholded 3D displays efficiently localized a total of 36 retention sites; 19 (52.7%) of these sites were not localized by CT because they were within the widely or homogeneously spreading non-bullous emphysematous lung tissues. The 3D displays enhanced the perception of anatomical configurations and the extent of ¹³³Xe retention compared with multislice tomograms. Postoperatively, 3D fusion display visualized the details of regional changes in retention, and changes in the retention index on the 3D display with a standardized threshold correlated well with changes in ¹³³Xe clearance time (T _1/2) and %FEV₁ (r = 0.881 and 0.856, respectively; P<0.0001). This preliminary study indicates that ¹³³Xe SPET and appropriately thresholded, topographic 3D displays are of potential use in selecting resection targets for LVRS, and in evaluating the treatment effects on regional ventilation. Received 23 September and in revised form 11 November     

Semi-quantitative ventilation/perfusion scintigraphy and single-photon emission tomography for evaluation of lung volume reduction surgery candidates: description and prediction of clinical outcome

Ventilation/perfusion scans with single-photon emission tomography (SPET) were reviewed to determine their usefulness in the evaluation of lung volume reduction surgery (LVRS) candidates, and as a predictor of outcome after surgery. Fifty consecutive planar ventilation (^99mTc-DTPA aerosol) and perfusion (^99mTc-MAA) scans with perfusion SPET of patients evaluated for LVRS were retrospectively reviewed. Technical quality and the severity and extent of radiotracer defects in the upper and lower halves of the lungs were scored from visual inspection of planar scans and SPET data separately. An emphysema index (EI) (extent × severity) for the upper and lower halves of the lung, and an EI ratio for upper to lower lung were calculated for both planar and SPET scans. The ratios were compared with post-LVRS outcomes, 3, 6 and 12 months after surgery. All perfusion and SPET images were technically adequate. Forty-six percent of ventilation scans were not technically adequate due to central airway tracer deposition. Severity, extent, EI scores and EI ratios between perfusion and SPET were in good agreement (r = 0.52–0.68). The mean perfusion EI ratio was significantly different between the 30 patients undergoing biapical LVRS and the 17 patients excluded from LVRS (3.3±1.8 versus 1.2±0.7; P<0.0001), in keeping with the anatomic distribution of emphysema by which patients were selected for surgery by computed tomography (CT). The perfusion EI ratio correlated moderately with the change in FEV₁ at 3 months (r = 0.37, P = 0.04), 6 months (r = 0.36, P = 0.05), and 12 months (r = 0.42, P = 0.03), and the transition dyspnea index at 6 months (r = 0.48, P = 0.014) after LVRS. It is concluded that patients selected to undergo LVRS have more severe and extensive apical perfusion deficits than patients not selected for LVRS, based on CT determination. SPET after aerosol V/Q imaging does not add significantly to planar perfusion scans. Aerosol DTPA ventilation scans are not consistently useful. Perfusion lung scanning may be useful in selecting patients with successful outcomes after LVRS. Received 9 October 1998 and in revised form 31 January 1999     

Clinical evaluation of99mTc-Technegas SPECT in thoracoscopic lung volume reduction surgery in patients with pulmonary emphysema

^99mTc-Technegas (Tcgas) SPECT is useful for evaluating the patency of the airway and highly sensitive in detecting regional pulmonary function in pulmonary emphysema. The aim of this study is to evaluate regional ventilation impairment by this method pre and post thoracoscopic lung volume reduction surgery (LVRS) in patients with pulmonary emphysema.Methods: There were 11 patients with pulmonary emphysema. The mean age of patients was 64.1 years. All patients were males. LVRS was performed bilaterally in 8 patients and unilaterally in 3 patients. Post inhalation of Tcgas in the sitting position, the subjects were placed in the supine position and SPECT was performed. Distribution of Tcgas on axial images was classified into 4 types, A: homogeneous, B: inhomogeneous, C: hot spot, D: defect. Three slices of axial SPECT images, the upper, middle and lower fields were selected, and changes in deposition patterns post LVRS were scored (Tcgas score).Results: Post LVRS, dyspnea on exertion and pulmonary function tests were improved. Pre LVRS, inhomogeneous distribution, hot spots and defects were observed in all patients. Post LVRS, improvement in distribution was obtained not only in the surgical field and other fields, but also in the contralateral lung of unilaterally operated patients. In 5 patients some fields showed deterioration. The Tcgas score correlated with improvements in FEV_1.0, FEV_1.0% and %FEV_1.0.Conclusion: Tcgas SPECT is useful for evaluating changes in regional pulmonary function post LVRS.     

多层螺旋CT三维重组对肺减容术前的形态学评估

目的探讨多层螺旋CT（MSCT）容积再现技术（VRT）显示肺气肿组织最佳的重组阈值区间，及其作为肺减容术（LVRS）靶区（拟行切除的肺气肿组织）显示手段的价值。方法对56例拟行LVRS的肺气肿患者行呼气相肺部扫描，按照CT检查时间的先后将患者分为A组和B组。以-1024～-960HU、-1024～-910HU分别作为LVRS手术靶区的重组阈值区间，对A组的原始薄层图像行VRT重组，并将2种重组阈值的VRT图像分别与轴面图像、多平面重组（MPR）图像对比，确定显示LVRS靶区的最佳重组阈值区间。B组根据A组选定的重组阈值区间进行VRT重组，计数并对比VRT与二维图像中直径≥3cm的肺大泡在各肺叶的分布，应用配对t检验验证2种计数结果。结果A组中以-1024 — -960HU作为肺气肿重组阈值区间的VRT图像对LVRS手术靶区显示较佳，与相对正常肺组织对比较鲜明，病变的程度、范围与二维图像符合程度高。B组中VRT图像与原始图像分析结果一致，对肺大泡的定位及计数结果与原始图像基本一致，肺右上、右中、右下、左上、左下叶计数对比，二维图像分别显示：（4．22±2．09）、（4、44±2．59）、（2．18±0．92）、（3．54±2．03）和（4．40±2．42）个；VRT分别显示：（4．12±2．12）、（4．44±2．59）、（2．18±0．87）、（3．50±1．99）和（4．28±2．28）个（t值分别为1．98、0．00、1．77、1．76、1．81，P值均〉0．05）。结论以-1024～-960HU作为肺气肿组织的重组阈值，VRT成像可以准确显示肺气肿的分布类型，立体直观的显示LVRS手术靶区，为术前形态评估和术后效果预测提供了新方法。     

X线透视引导下碘化油肺减容的动物实验研究

目的:研究X线影像引导下碘化油灌注联合丙烯酸树脂骨水泥封堵支气管实现肺减容的可行性。方法:20只健康新西兰白兔分为试验组12只,对照组8只,常规麻醉消毒,行气管切开,在数字多功能X线机下,置入导管,60%碘普罗胺支气管造影,然后选择性支气管插管,先后将适量的40%碘化油和骨水泥注射到所选肺叶内,对照组不注射骨水泥。常规喂养,术后20 d处死,肺组织病理切片。结果:试验组死亡4例,术后轻度发热6例,精神萎靡、活动减少、呼吸急促8例。胸部X线片示:术后见封堵肺叶内大片高密度影8例,第3～14天范围逐渐缩小,其余肺叶内有散在高密度影5例。解剖见封堵肺叶不张、体积缩小约2/3左右。病理切片:封堵肺组织弥漫性不张、机化,大量炎性渗出物和炎细胞浸润,胸膜明显增厚,未见脓肿形成。对照组:死亡1例,轻度发热2例,精神萎靡、活动减少6例,呼吸急促3例,3 d后症状消失。胸部X线片示:多处肺野散在点片状高密度影,7 d后减少,14 d后大部分消失。病理切片未见明显异常。结论:X线影像引导下,使用碘化油加骨水泥封堵支气管可导致肺炎变、机化和不张,从而实现微创下肺减容。     

平阳霉素碘油乳剂栓塞肺减容术的初步研究

目的探讨平阳霉素碘油乳剂栓塞结合近端支气管骨水泥封堵肺减容术的可行性及安全性。方法①平阳霉素碘油乳剂组12只成年兔经气管选择性插管至段支气管后,经导管向肺段(靶区)内注入平阳霉素碘油乳剂(分3个亚组,每组4只,平阳霉素用量分别为4、8和16mg加入1ml碘油中);②碘油对照组2只兔用同样方法向靶区内注入单纯碘油,碘油用量为1ml。两组于药物栓塞后,均用骨水泥(0.5ml)对近端支气管封堵。术后3d、1、2、4周行影像随访,并按预定时间取全肺作病理检查。结果碘油组与平阳霉素碘油乳剂各亚组表现相似,栓塞肺段明显膨胀不全,胸片及CT示靶区充有碘油并逐渐缩小。病理检查显示早期靶区呈急性渗出性炎症改变;4周后各组靶区均形成轻度纤维化,其周围见平行排列的萎陷肺泡,间质内以嗜酸粒细胞及淋巴细胞浸润为主伴大量肺巨噬细胞聚集,部分靶区出现小灶性坏死或化学性小脓肿(6/14,或43%)。靶区胸膜面光整,胸腔无渗液、脏壁层胸膜间无粘连。非靶区未发生明显的肺炎。结论经导管支气管平阳霉素碘油乳剂栓塞加骨水泥封堵及单纯碘油栓塞加骨水泥封堵皆是安全的,可引起稳定的肺减容。单纯碘油与平阳霉素碘油乳剂两组的肺纤维化程度未见显著差异,可能与样本较小和观察时间较短有关。     

重视介入性肺减容术的研究

介入性肺减容术是在外科切除肺减容术和内镜下非外科切除肺减容术的基础上发展起来的。它是一项X线导引下的经导管治疗技术,在靶肺叶经支气管行博来霉素(或无水乙醇)碘油乳剂栓塞的同时并对其近端支气管用骨水泥封堵,可获得稳定的肺纤维化和肺减容,即所谓的功能性肺叶切除。虽然此项介入治疗技术目前仍处于动物实验阶段,但已经显露出其临床应用潜力和广阔的前景。     

Visual classification of emphysema heterogeneity compared with objective measurements: HRCT vs spiral CT in candidates for lung volume reduction surgery

The aim of this study was to investigate whether spiral CT is superior to high-resolution computed tomography (HRCT) in evaluating the radiological morphology of emphysema, and whether the combination of both CT techniques improves the evaluation in patients undergoing lung volume reduction surgery (LVRS). The material consisted of HRCT (with 2-mm slice thickness) and spiral CT (with 10-mm slice thickness) of 94 candidates for LVRS. Selected image pairs from these examinations were evaluated. Each image pair consisted of one image from the cranial part of the lung and one image from the caudal part. The degree of emphysema in the two images was calculated by computer. The difference between the images determined the degree of heterogeneity. Five classes of heterogeneity were defined. The study was performed by visual classification of 95 image pairs (spiral CT) and 95 image pairs (HRCT) into one of five different classes of emphysema heterogeneity. This visual classification was compared with the computer-based classification. Spiral CT was superior to HRCT with 47% correct classifications of emphysema heterogeneity compared with 40% for HRCT-based classification ( p<0.05). The combination of the techniques did not improve the evaluation (42%). Spiral CT is superior to HRCT in determining heterogeneity of emphysema visually, and should be included in the pre-operative CT evaluation of LVRS candidates.     

Intraobserver and interobserver agreement of volume perfusion CT (VPCT) measurements in patients with lung lesions

Objectives

To evaluate intraobserver and interobserver agreement of manually encompassed lung lesions for perfusion measurements using volume-perfusion computed tomography (VPCT).

Materials and methods

Institutional review board approval and informed consent were obtained. HIPAA guidelines were followed. A 65-s dynamic study was acquired with scan parameters 80 kV, 60 mA s (80 mA s for patients ≥70 kg), 128 × 0.6 mm collimation. Blood flow (BF), blood volume (BV) and K^trans parameters were determined by syngo volume perfusion CT body with 88 lesions analyzed retrospectively.

Results

Within-subject coefficients of variation for intraobserver agreement (range 6.59–12.82%) were superior to those for interobserver agreement (range 21.75–38.30%). Size-dependent analysis revealed lower agreements for lesions <4 cm as compared to larger lesions. Additionally, agreements of the upper, middle and lower lung zones were different.

Conclusions

Intraobserver agreement was substantial for VPCT lung cancer perfusion measurements encouraging the use for tumor characterization and therapy response monitoring. Interobserver agreement is limited and unexperienced readers should be trained before using this new method.     

Co-registered perfusion SPECT/CT: Utility for prediction of improved postoperative outcome in lung volume reduction surgery candidates

Purpose

To directly compare the capabilities of perfusion scan, SPECT, co-registered SPECT/CT, and quantitatively and qualitatively assessed MDCT (i.e. quantitative CT and qualitative CT) for predicting postoperative clinical outcome for lung volume reduction surgery (LVRS) candidates.

Materials and methods

Twenty-five consecutive candidates (19 men and six women, age range: 42-72 years) for LVRS underwent preoperative CT and perfusion scan with SPECT. Clinical outcome of LVRS for all subjects was also assessed by determining the difference between pre- and postoperative forced expiratory volume in 1 s (FEV₁) and 6-min walking distance (6MWD). All SPECT examinations were performed on a SPECT scanner, and co-registered to thin-section CT by using commercially available software. On planar imaging, SPECT and SPECT/CT, upper versus lower zone or lobe ratios (U/Ls) were calculated from regional uptakes between upper and lower lung fields in the operated lung. On quantitatively assessed CT, U/L for all subjects was assessed from regional functional lung volumes. On qualitatively assessed CT, planar imaging, SPECT and co-registered SPECT/CT, U/Ls were assessed with a 4-point visual scoring system. To compare capabilities of predicting clinical outcome, each U/L was statistically correlated with the corresponding clinical outcome.

Results

Significantly fair or moderate correlations were observed between quantitatively and qualitatively assessed U/Ls obtained with all four methods and clinical outcomes (−0.60 ≤ r ≤ −0.42, p < 0.05).

Conclusion

Co-registered perfusion SPECT/CT has better correlation with clinical outcome in LVRS candidates than do planar imaging, SPECT or qualitatively assessed CT, and is at least as valid as quantitatively assessed CT.     

320层动态容积CT血管成像在肺动脉栓塞中的诊断价值

目的探讨320层动态容积CT血管成像在诊断肺动脉栓塞中的价值。方法回顾性分析30例临床确诊为肺动脉栓塞的320层动态容积CT肺动脉成像资料,并用最大密度投影(MIP)、多平面重组(MPR)、容积再现(VR)等方法显示肺动脉。结果 30例患者中,其中左右肺动脉栓塞有15支,叶肺动脉栓塞30支,段及亚段肺动脉栓塞60支。偏心型45支,闭塞型40支,中央型12支,附壁环形型5支。结论 320层动态容积CT肺动脉成像可作为肺动脉栓塞诊断的首选方法。     

单侧肺减容术肺切除量对兔阻塞性肺气肿疗效的影响

目的　评价单侧肺减容术 (LVRS)肺切除量对兔阻塞性肺气肿疗效的影响。方法　建立新西兰大白兔阻塞性肺气肿模型 ,将 5 0只肺气肿兔随机分为肺气肿组 (A组 )、小量LVRS组 (B组 )、中量LVRS组 (C组)、大量LVRS组(D组 )和假手术组(E组 ) 5组 ,每组各 10只 ,8周后进行肺功能和肺组织学检查。结果　与A组比较 ,C组的潮气量、0 3s用力呼气容积 (FEV0 3 )、FEV0 3 /FVC(用力肺活量)、PaO2 、平均肺泡数和肺泡隔面密度增加 ,功能残气量、PaCO2 、肺总容积和肺泡直径降低 (P <0 0 5 ) ,而B、D、E组无明显变化 (P >0 0 5 )。组织学检查C组气道炎症减轻 ,肺气肿明显改善。结论　单侧适量LVRS可有效改善兔阻塞性肺气肿。     

PET-CT靶区勾画方式对肺癌治疗计划的影响

目的 研究肺癌放射治疗中应用PET-CT定位时不同靶区勾画方式对靶区体积以及正常组织受量的影响。方法选择2例肺癌患者。扫描后进行图像融合,并根据不同阈值勾画靶区并设计治疗计划,比较各个靶区大小以及正常组织受量。勾画靶区时采用的3个阈值分别为K_max(50%)、K_max(40%)和SUV_2.5。K_max(50%)和K_max(40%)分别是最大单位体积摄取值的50%和40%,SUV_2.5是标准摄取值2.5。根据上述特定阈值勾画大体肿瘤体积(GTV),考虑到器官运动和摆位误差,在GTV基础上外放1.5cm作为计划靶体积(PTV)。勾画的正常组织包括肺和脊髓,并用剂量体积直方图加以比较。结果3个阈值勾画的结果不同,2例患者GTV分别为23.1、34.9、49.2 cm³和58.1、80.3、163.4cm³,PTV分别为169.5、222.1、261.9cm³和286.8、349.7、560.5cm³;全肺受量超过20Gy的体积分别为14.4%、17.2%、19.5%和15.2%、16.0%、20.2%,全肺平均剂量分别占16.2%、19.4%、21.4%和12.7%、14.4%、19.4%。≤1cm³脊髓的受量分别占30.6%、34.3%、44.9%和27.3%、35.2%、67.1%。结论应用PET-CT定位时采用不同靶区勾画方式对GTV、PTV和正常组织受量影响很大。在正常组织能够耐受情况下,应考虑采用靶区覆盖较好的阈值勾画靶区。     

自制气道封堵器在经支气管镜肺减容术中的应用

目的 探讨自制内塞式支气管封堵器在经支气管镜肺减容术(BLVR)中的应用效果.方法 选择2例稳定期重度慢性阻塞性肺疾病(COPD)患者,在支气管镜引导下于靶位支气管置入1或2枚自制的镍钛合金封堵器,比较患者术前、术后7个月的肺功能、动脉血气、圣·乔治呼吸疾病问卷(SGRQ)、胸部CT及并发症等指标的差异,评价BLVR的疗效.结果 置入的封堵器无一脱落或移位;局部黏膜仅见轻度肉芽组织增生;被封堵的靶位肺组织出现不张或膨胀不全.术前和术后7个月,病例1、2的静态肺容积(VC)分别从3.08L上升至3.57L,2.19L上升至2.58L;用力肺活量(FVC)分别从2.87L上升至3.57L,2.60L上升至2.58L;SGRQ调查显示患者的呼吸困难症状显著改善,分值分别从62降低至26,48降低至23;但动脉氧分压提高均不明显.2例患者均未发生阻塞性肺炎、气胸等严重并发症.结论 本课题组自行研制的封堵器在两例重度COPD患者中初步应用已显示出其置入简便、稳定性好、封堵效果确实、并发症少的优点,能够达到肺减容及改善肺功能的目的.     

单肺移植治疗终末期肺气肿的围手术期影像学改变

目的 气肿、肺功能重度减损的患者进行左肺移植，使用X线及CT观察手术前后影像学变化。结果 术后移植肺大片雪白致密影，呈完全不透亮的肺再植反应，第4天曾一度出现急性对侧患肺过度膨胀，纵隔左移、压迫移植肺，术后93h顺利脱机，第5天出现对侧肺感染，术后第9天胸片示移植肺片状模糊影，呈磨玻璃样改变，经活检为急性排异，经大剂量甲基泼尼松龙冲击治疗后症状消退，术后40d胸部CT示左肺扩张良好，左肺血液灌注良好，术后肺功能明显改善，术后47d出院，现已恢复工作。结论 单肺移植术后影像学改变对术后并发症的诊断与处理有非常重要的指导价值。     

螺圈加胶水法封堵兔肺支气管的实验研究

目的评价对于兔支气管最佳的螺圈加胶水封堵组合。方法分别以3mm螺圈 生物蛋白胶(A组)、3mm螺圈 NBCA胶(B组)、2mm螺圈 NBCA胶(C组)及4mm螺圈 NBCA胶(D组)封堵兔两肺前叶支气管,每组共8个部位。分别观察螺圈咳出、移位、肺叶萎陷、炎症程度及螺圈处异物肉芽肿的状况(分别记为0~2分)。结果B组评分明显高于其他组,与A组差异有显著性(P=0.009),与C组、D组差异亦有显著性(P值均为0.015)。结论适当大小的螺圈(直径3mm)可减少咳出、移位率和并发症;此外,NBCA胶比生物蛋白胶能更有效地造成肺萎陷。     

低剂量条件下全模型迭代重建技术的肺容积定量研究

目的 探讨低剂量条件下全模型迭代重建法(IMR)、混合迭代重建法(iDose4)和滤波反投影(FBP)3种重建技术对肺容积定量测量的影响,并比较不同重建方法的图像噪声大小.方法 应用飞利浦256层CT对70例体检者行低剂量胸部CT扫描,原始数据分别用IMR(算法:Routine、SharpPlus、Soft Tissue,等级:1～3,共9种)、iDose4以及FBP技术进行重建,设定CT值<-950 HU的区域为肺气肿区,分别计算各组的总肺容积(TLV)、总肺气肿容积(TEV)、肺气肿指数(EI)以及客观图像噪声(OIN),并比较各组的差异.结果 肺容积定量参数中,除TLV各组间定量结果无明显统计学差异外(P=1.000),TEV、EI组间均有明显统计学差异(P=0.000).IMR中SharpPlus算法(等级1～3)所测定的TEV、EI高于其余组别.对于噪声,IMR中SharpPlus算法水平1(IMR-S-L1)的OIN最高,其次为FBP,iDose4算法的OIN低于SharpPlus算法但高于Routine和Soft Tissue算法.结论 在低剂量条件下,IMR中SharpPlus算法会影响肺容积参数的测定,且图像噪声大,因此不推荐使用SharpPlus算法进行肺容积定量分析,IMR中Routine与Soft Tissue算法均不影响肺容积参数测定,且较FBP和iDose4能明显降低图像噪声.     

Automated lung segmentation in X-ray computed tomography: development and evaluation of a heuristic threshold-based scheme

RATIONALE AND OBJECTIVES: To develop and evaluate a reliable, fully-automated lung segmentation scheme for application in X-ray computed tomography. MATERIALS AND METHODS: The automated scheme was heuristically developed using a slice-based, pixel-value threshold and two sets of classification rules. Features used in the rules include size, circularity, and location. The segmentation scheme operates slice-by-slice and performs three key operations: (1) image preprocessing to remove background pixels, (2) computation and application of a pixel-value threshold to identify lung tissue, and (3) refinement of the initial segmented regions to prune incorrectly detected airways and separate fused right and left lungs. RESULTS: The performance of the automated segmentation scheme was evaluated using 101 computed tomography cases (91 thick slice, 10 thin slice scans). The 91 thick cases were pre- and post-surgery from 50 patients and were not independent. The automated scheme successfully segmented 94.0% of the 2,969 thick slice images and 97.6% of the 1,161 thin slice images. The mean difference of the total lung volumes calculated by the automated scheme and functional residual capacity plus 60% inspiratory capacity was -24.7 +/- 508.1 mL. The mean differences of the total lung volumes calculated by the automated scheme and an established, commonly used semi-automated scheme were 95.2 +/- 52.5 mL and -27.7 +/- 66.9 mL for the thick and thin slice cases, respectively. CONCLUSION: This simple, fully-automated lung segmentation scheme provides an objective tool to facilitate lung segmentation from computed tomography scans.