【作者】 常青；

【导师】 吴宁； 欧阳汉；

【作者基本信息】 中国协和医科大学 ， 影像医学与核医学， 2008， 博士

【摘要】 第一部分：3．0T MR胸部不同扫描序列的图像质量分析目的：比较FSE-T1、FSE-T2、FSE-T2-FS、T2^*序列及LAVA增强扫描序列对胸部扫描的图像质量，以摸索3．0T MR进行胸部扫描的合理扫描序列及序列组合。材料和方法：采用3．0T MR对53例肺部肿瘤的患者进行胸部扫描，其中1例伴阻塞性炎症或阻塞性肺不张。均进行FSE-T1、FSE-T2及FSE-T2-FS扫描，其中48例进行T2^*扫描，48例进行LAVA增强扫描，就各序列对整体图像质量、病变、支气管、纵隔大血管、胸壁的显示情况、伪影及肿物与阻塞性病变的边界显示情况分别进行评分和比较。结果：五个序列间在图像整体质量、对病变、支气管及分支、纵隔大血管的显示及伪影的差异有极显著性意义（P=0．000），对胸壁的显示情况差异有显著性意义（P=0．018）。FSE-T2、FSE-T2-FS及LAVA序列的图像整体质量较高，优于FSE-T1及T2^*序列（P<0．01），但FSE-T2-FS序列对大血管的显示能力不及FSE-T2及LAVA序列（P<0．05）；T2^*序列对支气管的显示不及其他四个序列（P<0．01）；LAVA序列的伪影程度最轻，均为无或轻度伪影；FSE-T1的伪影明显，与LAVA序列间差异有显著性意义（P<0．05）。19例伴阻塞性炎症或阻塞性肺不张者，FSE-T2、FSE-T2-FS及LAVA序列均能区分肿物与阻塞性病变的边界，而FSE-T1及T2^*序列仅能对2例患者作出区分。结论：应用3．0T超高场强MR进行胸部扫描应常规选择FSE-T2序列和LAVA增强序列。FSE-T1及FSE-T2-FS序列图像质量不及FSE-T2序列和LAVA增强序列，但有助于组织类型判断。T2^*序列由于图像质量不佳，在肺癌MR扫描中应用价值有限。第二部分：3．0T MR肺癌动态增强特征及在放化疗前后的变化目的：前瞻性研究肺癌在3．0T MR动态增强扫描的特点及其与组织病理学和MVD的相关性；分析肺癌放化疗治疗前后MR动态增强扫描参数及曲线形态的动态变化，为探索3．0T MR在肺癌放化疗早期疗效评价中的作用奠定基础。材料和方法：应用3．0T MR对37例经病理证实为肺癌的患者进行胸部动态增强扫描，采用LAVA序列间断扫描至注射造影剂后4min，计算增强扫描各期肿瘤相对强化度（SI％），绘制T-SI％曲线，将曲线形态分为A型（速升下降型）、B型（速升平台型）、C型（速升-缓升型）和D型（持续低平型），计算强化参数：早期强化峰值(SI_EP％)、早期峰值强化时间(T_EP)、最大强化峰值(SI_peak％)、最大强化峰值时间(T_peak)。比较不同大小（≤5cm和>5cm）、部位（中央型和周围型）、组织学类型（鳞癌和腺癌）、分化程度（高、中、低分化）、分期（早中期和晚期）间T-SI％曲线形态及强化参数；对10例行手术治疗者切除的组织进行CD31和CD34染色，分析肿瘤强化参数与MVD的相关性；对17例接受放化疗者，比较放化疗前后T-SI％曲线形态及强化参数的变化。结果：肿瘤最大径≤5cm和最大径>5cm者间强化参数的差异有显著性意义，肿瘤最大径≤5cm者SI_EP％、SI_peak％均高于肿瘤最大径>5cm者，其他各组间SI_EP%、SI_peak％均无统计学差异。SI_EP％、SI_peak％与MVD呈正相关。17例行放化疗治疗患者，近期疗效缓解者与未缓解者之间，增强扫描强化参数无统计学意义。放化疗前、中、后肿瘤强化参数SI_EP％、SI_peak％无统计学意义，但放疗后T_peak较放疗前明显延迟（P=0．005）。T-SI％曲线形态放疗前呈速升-下降型4／17和速升-平台型13／17，而放疗后呈速升-平台型3／10和速升-缓升型7／10。结论：SI_EP％、SI_peak％与肿瘤大小有关，肺癌最大径≤5cm者SI_EP％、SI_peak％明显高于最大径>5cm者。SI_EP％、SI_peak%与MVD呈正相关，提示其可以反映肿瘤MVD情况。本组小样本结果显示肺癌放化疗后动态增强T_peak较治疗前延迟，动态增强MR曲线形态疗后发生变化。第三部分：3．0T MR肺癌扩散成像特点及放化疗前后的变化目的：前瞻性研究3．0T MR在肺癌的扩散特点；观察其在放化疗前后的变化，以期对肺癌疗效评估发挥作用。材料和方法：对36例病理证实为肺癌的患者进行DWI成像，放化疗治疗后重复DWI成像。DWI图像质量分为好（病变清楚，无明显磁敏感伪影）、一般（病变周围见高信号，或出现轻度磁敏感伪影）、差（病变不清，变形严重，出现严重磁敏感伪影），DWI图像变形严重者为失败：比较不同病理类型肺癌的ADC值差异；观察治疗前后ADC值变化。结果：36例患者中22例（61．1％）DWI图像质量评价为优或一股，其中鳞癌10例，ADC值为1．41×10^-3mm²／s±0．26×10^-3mm²／s：腺癌9例，ADC值为1．42×10^-3mm²／s±0．63×10^-3mm²／s，两者ADC值差异无显著性意义（P=0．970）。14例（38．9％）评价为失败，未能进一步评价。7例放化疗前后DWI图像均为优或一般者，放疗前ADC值为1．13×10^-3mm²／s±0．25×10^-3mm²／s，放疗后ADC值为1．81×10^-3mm²／s±0．25×10^-3mm²／s，放疗前后ADC值的差异有显著性意义（P=0．000）。结论：放化疗后肺癌ADC值明显增高，提示DWI成像在监测肺癌放化疗后早期功能学变化方面有潜在应用价值，但目前DWI成像图像质量尚不能满足临床常规应用。更多还原

【Abstract】 PartⅠImage Analysis of 3.0T MR Sequences in the Chest.PURPOSE: To compare the image quality of FSE-T1, FSE-T2, FSE-T2-FS, T2^* and LAVA-enhanced sequences with 3.0T MR in the chest. MATERIALS ANDMETHODS: Fifty-three patients with suspected lung cancer underwent chest MRI. Nineteen out of them combined with obstructive atelectasis or pneumonia at the examination time. The FSE-TI, FSE-T2 and FSE-T2-FS sequences were obtained in all patients. T2^* and LAVA-enhanced sequences were obtained in 48 patients, respectively. The quality of MR images was evaluated and scored according to overall image quality, the image quality of masses, of bronchi, of vessels, of chest wall and of the artifacts. The borders of masses and obstructive lesions were evaluated, too.RESULTS: The overall MR image quality, the image quality of masses, of bronchi, of vessels, of chest wall and of the artifacts were significantly different in five sequences （P<0.05）. The overall MR image quality of FSE-T2, FSE-T2-FS and LAVA-enhanced sequences was significantly better than that of FSE-T1 and 12^* sequences （P<0.01） , and the image quality of FSE-T2-FS sequences was no better than that of FSE-T2 and LAVA-enhance sequences on vessel displays （P<0.05）. T2^* sequence was inferior to other four sequences on airway displays （P<0.01）. There were more artifacts in FSE-T1 sequence than in LAVA-enhanced sequence （P<0.05）, in which no or little artifacts were encountered. The tumor and adjacent obstructive lesions could be differentiated on FSE-T2. FSE-T2-FS, and LAVA-enhanced sequences in all 19 patients with obstructive atelectasis or pneumonia but only in 2 cases on FSE-T1 and T2^* sequences. CONCLUSION: FSE-T2 and LAVA-enhanced sequences with 3.0T MR could render images with good quality in patients with lung cancer. The image quality of FSE-T2-FS and FSE-T1 is inferior to FSE-T2 and LAVA-enhanced sequence, but they can be used as supplement in the tissue identification. The use of T2^* sequence is limited in the chest MRI examinations because of dissatisfied image quality. PartⅡ3.0T Dynamic Contrast-enhanced Magnetic Resonance Imagingof Lung Cancer: Characterization and Monitoring after Chemoradiation.PURPOSE: To prospectively investigate enhancing characteristics of lung cancer, correlate them with pathology and tumor microvessel density, monitor the enhancing parameters and the T-SI% curve types of lung cancer after chemoradiation, and assess early response after chemoradiation with dynamic contrast-enhanced magnetic resonance （DCE-MR） imaging. MATERIALS AND METHODS: Thirty-seven patients with pathologically proven lung cancer underwent DCE-MR with LAVA sequence. DCE-MR images were acquired intermittently for a total of 4 minitues on 3.0T MR scanner. The relative enhancing percentage （Sl%） of each time point was measured. The shapes of T-SI% curves were defined as A （rapidly ascending followed with descending branch）, B （rapidly ascending branch followed with plateau） and C （rapidly ascending followed with slowly ascending branch） and D （ persistently low and flat）. The early peak enhancement (SI_EP>%). early peak time (T_EP), maximum enhancement (SI_peak%), and peak time (T_peak) were recorded and compared according to different dimension, location, histological types, clinical stages and differentiation grades of lung cancer. The SI_EP% and SI_peak% were correlated with microvessel density in ten patients who underwent the resection of tumor. Seventeen patients who underwent chemoradiation were examined repeatedly pre-, mid- and post-chemoradiation, the shapes of T-SI% curves, SI_EP% and SI_peak% of pre-, mid-and post-treatment were compared. RESULTS: The SI_EP% and SI_peak% of tumors with smaller dimension （≤5cm） were significantly higher than those with larger dimension （>5cm）. The SI_EP% and SI_peak% were positively correlated with microvessel density. In 17 patients who underwent chemoradiation. no significant differences were observed in the enhancing parameters between response group and nonresponse group. The SI_EP% and SI_peak% of pre-, mid- and post-chemoradiation were not significantly different, but T_peak increased after the treatment （P=0.005）. The T-SI% curves were type A （4/17） and type B （13/17） before chemoradiation. however they were type B （3/10） and type C （7/10） after chemoradiation. CONCLUSION:The SIep% and SI_peak% of lung cancer with smaller dimension are higher than those with larger dimension. The SIep% and SI_peak% are positively correlated with the tumor MVD. The small sample research demonstrates the T_peak delayed and T-SI% curve type changed after chemoradiation. PartⅢ3.0T MR Diffusion-weighted Imaging in Assessment of TumorResponse after Chemoradiation in Patients with Lung Cancer.PURPOSE: To investigate characteristics of diffusion weighted imaging （DWI） of lung cancer, monitor the apparent diffusion coefficient （ADC） after chemoradiation and assess the value of DWI in early response of lung cancer after chemoradiation.MATERIALS AND METHODS: Thirty-six patients with pathologically proven lung cancer underwent DWI. Fifteen patients who underwent chemoradiation were scaned prior to and post chemoradiation. The quality of diffusion weighed images were evaluated on 3-level grades as good, moderate and failed. ADCs of the lung cancers which were graded as good and moderate were measured from ADC mapping. ADCs were compared among the different types of lung cancers and pre- and post-chemoradiation. RESULTS: The quality of diffusion weighed images was graded as moderate or good in 22 patients, and as failure in 14 patients. ADCs were 1.41×10^-3 mm²/s±0.26×10^-3mm²/s （mean±standard deviation） for squamous cell carcinoma, and 1.42×10^-3mm²/s±0.63×l0^-3mm²/s for adenocarcinoma. There were no significant differences between squamous cell carcinoma and adenocarcinoma （P=0.970）. The quality of diffusion weighted images of 7 patients were graded as good or moderate pre- and post-chemoradiation. ADCs were 1.13×10^-3 mm²/s±0.25×10^-3mm²/s for pre-therapy, 1.81×10^-3mm²/s±0.25×10^-3mm²/s for post-therapy. The differences of ADC values before and after chemoradiation were statistically significant （P=0.000）. CONCLUSION: The ADCs of lung cancer are markedly increased after chemoradiation. The DWI has potential value for monitoring early response of lung cancer after chemoradiation, but the image quality of DWI is not satisfied for routine clinical application rencently.更多还原