3.0T心脏磁共振成像在儿童心肌炎中的技术及临床应用研究

发布时间：2018-04-28 12:20

本文选题：双源射频发射 + 心脏磁共振　；参考：《山东大学》2017年博士论文

【摘要】：第一部分3.0T双源射频发射技术在儿童心脏磁共振成像中的价值目的利用3.0 T双源射频发射技术对心脏行适形射频匀场,并与传统的单源射频系统比较,评估其在儿童心脏磁共振(cardiac magnetic resonance,CMR)成像B1射频场均匀性及电影图像质量(图像对比度及失谐共振伪影)中的价值。研究背景同成人相比,儿童CMR成像存在一系列技术难题:儿童心脏解剖结构小,心率快,扫描过程中不能保持静止以及不能配合屏气扫描等。高场强心脏磁共振成像能够满足儿童CMR成像所需的高时间、空间分辨率,多信号采集技术可以减少儿童呼吸运动伪影及不自主运动伪影,但其应用又会带来磁场均匀性减低、图像质量下降等问题。材料与方法本研究纳入60位儿童,均在双源及传统单源两种射频适形发射技术进行CMR成像,其中30位儿童在自由呼吸条件下进行扫描,30位在屏气条件下扫描。心脏B1射频场均匀性采用水平长轴位Bl-map图所达到翻转角的平均百分比及翻转角变异系数(coefficient of variation,CV)进行评估。由双源射频发射技术及传统单源所得的B1射频场均匀性以及心脏电影图像的对比度采用T检验进行比较。两位经验丰富的放射科医生分别对电影图像中的伪影进行1-4级评分,伪影评分的结果进行Mann-Whitney U检验,观察者间的一致性分析采用Kappa检验。结果同传统单源射频技术相比,双源射频适形发射技术明显提高了 B1射频场实际平均翻转角百分比(自由呼吸组:104.2±4.6 VS 95.5±6.3,P0.001;屏气组:101.5±5.1 VS 92.5±6.3,P0.001),减小了反转角的 CV(自由呼吸组:0.06±0.02 VS 0.09±0.03,P0.001;屏气组:0.07±0.03 VS 0.10±0.04,P=0.005)。双源射频技术显著提高了心脏电影左、右心室心腔血池-室间隔的对比度(P值均0.05)。心脏水平长轴位电影图像的失谐伪影明显减少(P值均0.05),观察者间的一致性较好(kappa:0.68-0.74)。结论同传统单源射频技术相比,双源射频适形发射技术能够显著改善3.0 T儿童CMR成像B1射频场的均匀性,提高电影图像质量。这项技术有待于应用到儿童CMR成像中。第二部分3.0 T心脏磁共振成像在儿童爆发性心肌炎诊断及短期预后中的价值目的本研究的目的为分析不同时期儿童爆发性心肌炎(Fulminant myocarditis,FM)的心脏磁共振(Cardiac magnetic resonance,CMR)表现,评估儿童FM的短期预后并找出其预后因子。研究背景FM是一种起病急骤,可迅速导致心室收缩功能明显异常及心衰的心肌炎性疾病。目前,CMR检查已经成为心肌炎诊断及评估的重要非侵入性检查工具。但CMR在FM诊断及预后中的价值鲜有报道。材料与方法本研究纳入8位进行两次CMR检查的FM儿童。首次CMR检查于FM发病10天(范围,7-20天)时进行,随访检查于发病55天(范围,33-75天)时进行。采用配对T检验及Mann-Whitney U检验对FM儿童首次及随访CMR检查时的心脏形态、功能及心肌组织特性进行比较。从临床表现、血清学及CMR表现三方面分析儿童FM的短期预后。对预后不同的FM儿童,比较其首次CMR检查时的临床信息及CMR表现,找出FM儿童的短期预后因子。结果8位FM儿童的中位年龄为8.5岁(范围,3-14岁)。在首次CMR检查中,早期心肌强化(early gadolinium enhancement,EGE)是儿童FM最常见的CMR表现(100.0%);87.5%的儿童FM表现为心肌T2信号增加及心肌延迟强化(late gadolinium enhancement,LGE);心肌增厚见于75.0%儿童FM,左心室射血分数(left ventricle ejection fraction,LVEF)增加见于 50.0%的儿童 FM。在随访 CMR检查中,仅有3位儿童FM表现为心肌LGE(37.5%),1位表现为心肌T2信号增加(12.5%),LVEF增加仅见于1位FM儿童(12.5%)。首次及随访CMR表现中的心肌厚度、左心室舒张末期横径、收缩末期容积、LVEF、左心室质量、T2信号对比及LGE面积具有明显统计学差异(P=0.011,P=0.042,P=0.016,P=0.001,P=0.003,P=0.011,P=0.020)。5位FM儿童的临床表现、血清学及CMR表现完全恢复正常。短期预后好的FM儿童更常表现111°房室传导阻滞(5例VS 0例)及小面积的 LGE(104.0±14.5 mm2 VS 138.0±25.2 mm2)。结论儿童FM的CMR表现具有特征性,CMR成像对FM早期诊断的敏感性高。FM儿童短期预后较好,Ⅲ°AVB的发生及LGE面积大小可能有助于FM儿童的短期预后评估。CMR成像在儿童FM的早期诊断及短期预后中均表现出巨大价值。第三部分采用定量T1及T2 mapping技术评估心肌炎儿童"正常,"心肌的潜在心肌损害目的探究T1及T2 mapping技术是否能够识别出心肌炎儿童"正常"心肌中的潜在心肌损害,并评估T1及T2值同左心室心功能间的关系。研究背景传统的心脏磁共振(cardiac magnetic resonance,CMR)成像对心肌炎局限性心肌损害的诊断准确性较高,而对于弥漫性心肌损害的敏感性可能略有下降。新的CMR成像技术-T1,T2 mapping技术能够对心肌信号进行量化评估,并可以发现传统CMR表现正常的心肌中所存在的弥漫性心肌损害。材料与方法本研究纳入46位受试者-20位急性心肌炎(acutemyocarditis,AM)儿童,11位慢性心肌炎(chronic myocarditis,CM)儿童及15位健康儿童(normal controls,NC)。采用线性回归分析比较AM,CM及NC三组受试者水平长轴(Horizontal long axis,HLA)位和短轴(Short axis,SA)位"正常"心肌的T2值,初始T1值,强化后T1值和细胞外容积(extracellular volume,ECV)。强化后T1值、ECV同左心室心功能之间的关系采用多元线性回归分析进行评估。结果同NC组比较,AM组病人"正常"心肌的强化后T1值明显低于NC组(HLA:718.3±65.3 ms VS 776.5±62.4 ms,P=0.005;SA:723.9±61.2 ms VS 787.7±62.3 ms,P=0.002)。CM组病人"正常"心肌的强化后T1值明显低于NC组(HLA:693.0±77.7 ms VS 776.5±62.4 ms,P=0.001;SA:710.9±75.9 ms VS 787.7±62.3 ms,P=0.001),而ECV 值明显增高(SA:30.1 ±2.8 VS 27.0±2.4,P=0.004)。在 CM 组,强化后 T1 值及ECV同左心室射血分数(left ventricle ejection fraction,LVEF)及每搏输出量(stroke volume,SV)间具有显著关联(P0.05)。结论强化后T1值和ECV能够识别出心肌炎儿童"正常"心肌中的潜在心肌损害,并在CM病人中同LVEF及SV具有显著关联。Mapping技术能够增加心肌炎CMR诊断的敏感性,可以作为心肌炎病情进展评估及疗效评估的一种有效手段。
[Abstract]:The value of 3.0T dual source radiofrequency (RFID) technique in children's cardiac magnetic resonance imaging (fMRI) in the first part is to use 3 T dual source radiofrequency emission (RFID) technique to homogenate the conformal radiofrequency of the heart. Compared with the traditional single source radio frequency system, the uniformity of the radio frequency field of the cardiac magnetic resonance (CMR) imaging in children and the film map of the radio frequency field are evaluated. Compared with adults, there are a series of technical problems in children's CMR imaging: the children's heart structure is small, the heart rate is fast, the scanning process can not keep still, and the breath holding scan can not be matched. High field cardiac magnetic resonance imaging can meet the needs of children's CMR imaging. The high time, spatial resolution, multi signal acquisition technology can reduce the artifact of children's breathing motion and the immobile artifact, but its application will bring about the reduction of magnetic field uniformity and the decline of image quality. Materials and methods are included in the study of 60 children with two radio-frequency adaptive emission techniques of dual source and single source in CMR imaging. 30 children were scanned under free breathing conditions, and 30 were scanned under breath holding conditions. The average percentage of the B1 radiofrequency field uniformity by the horizontal long axis Bl-map map and the variable coefficient of variation (coefficient of variation, CV) were evaluated by the horizontal long axis position. The dual source radiofrequency emission technology and the traditional single source B1 shot were used. The frequency field uniformity and the contrast of the heart film images were compared by T test. Two experienced radiologists scored 1-4 grades on the artifact in the film images, the results of the artifact score were tested by Mann-Whitney U test, and the consistency analysis between the observers was tested by the Kappa test. The actual average turning angle percentage of B1 radio frequency field (free breathing group: 104.2 + 4.6 VS 95.5 + 6.3, P0.001, 101.5 + 5.1 VS 92.5 + 6.3, P0.001), decreased the CV (free breathing group: 0.06 + 0.02 VS 0.09 + 0.03, P0.001, and breath holding group: 0.07 + 95.5 + VS + + P=0.005). Dual source radiofrequency technology significantly enhanced the contrast of left and right ventricular septum interventricular septum (P value of 0.05). The detuning artifacts of the long axis image of the heart were significantly reduced (P value was 0.05) and the consistency between the observers was better (kappa:0.68-0.74). Conclusion compared with the traditional single source radio frequency technology, the dual source radio frequency adaptive emission technique was compared. It can significantly improve the uniformity of the B1 radiofrequency field of 3 T children's CMR imaging and improve the quality of the film image. This technique needs to be applied to children's CMR imaging. The purpose of the second part 3 T cardiac magnetic resonance imaging in the diagnosis and short-term prognosis of children with explosive myocarditis Cardiac magnetic resonance (Cardiac magnetic resonance, CMR) manifestations of Fulminant myocarditis (FM), to assess the short-term prognosis of children's FM and to identify its prognostic factors. Background FM is an acute onset, which can rapidly cause obvious ventricular systolic dysfunction and heart failure of cardiac myositis. Currently, CMR examination has become a diagnosis of myocarditis. An important noninvasive examination tool for the assessment. But the value of CMR in the diagnosis and prognosis of FM was rarely reported. Materials and methods were included in 8 FM children with two CMR examinations. The first CMR examination was performed at 10 days (range, 7-20 days) of FM, followed up for 55 days (range, 33-75 days). Paired T test and Mann-W were used. Hitney U test compared the heart shape, function and myocardial tissue characteristics of FM children at the first and follow up CMR examination. The short-term prognosis of children's FM was analyzed from three aspects of clinical manifestation, serology and CMR performance. The clinical information and CMR manifestations of the first CMR examination were compared to the FM children with different prognosis, and the short-term prognosis of FM children was found out. Results the median age of 8 FM children was 8.5 years (range, 3-14 years). In the first CMR examination, early myocardial enhancement (early gadolinium enhancement, EGE) was the most common CMR performance of children FM (100%); 87.5% of children FM showed increased myocardium T2 signal and myocardial extension Chi Qianghua (late gadolinium); myocardial thickening was found in 75. 0% children FM, left ventricular ejection fraction (left ventricle ejection fraction, LVEF) increased in 50% of children FM. in the follow-up CMR examination. Only 3 children showed FM in LGE (37.5%), 1 showed increased myocardial T2 signal (12.5%), LVEF increased only in 1 children (12.5%). Shi Shuzhang terminal transverse diameter, end systolic volume, LVEF, left ventricular mass, T2 signal contrast and LGE area had significant statistical differences (P=0.011, P=0.042, P=0.016, P=0.001, P=0.003, P=0.011, P=0.020).5 bit FM children. The serology and manifestations were completely restored to normal. The children with good short-term prognosis were more often characterized by 111 degrees of atrioventricular conduction resistance. Stagnation (5 cases of VS 0 cases) and small area LGE (104 + 14.5 mm2 VS 138 + 25.2 mm2). Conclusion the CMR expression of FM in children is characteristic. CMR imaging for early diagnosis of FM.FM children has better short-term prognosis. The occurrence of III degree AVB and the size of LGE area may help the short-term prognosis evaluation of children. The third part uses quantitative T1 and T2 mapping techniques to evaluate the potential myocardial damage of myocarditis in children with myocarditis by using quantitative T1 and T2 techniques to explore whether T1 and T2 mapping technology can identify potential cardiac damage in the "normal" myocardium of children with myocarditis, and evaluate the value of T1 and T2 value to the left ventricular cardiac function. The diagnostic accuracy of traditional cardiac magnetic resonance (CMR) imaging for myocarditis localized myocardial damage is higher, and the sensitivity to diffuse myocardial damage may be slightly decreased. The new CMR imaging technique -T1, T2 mapping technology can quantify the myocardial signal and can find the transmission of myocardium. CMR showed diffuse myocardial damage in normal myocardium. Materials and methods were included in 46 subjects with acutemyocarditis (AM), 11 chronic myocarditis (chronic myocarditis, CM) and 15 healthy children (normal controls, NC). Linear regression analysis was used to compare AM, CM, and three groups. The Horizontal long axis, HLA position and the short axis (Short axis, SA) position of the "normal" cardiac muscle T2 value, initial T1 value, enhanced T1 value and extracellular volume (extracellular volume). The T1 value of normal myocardium was significantly lower than that in group NC (HLA:718.3 + 65.3 MS VS 776.5 + 62.4 MS, P=0.005; SA:723.9 + 61.2 MS VS 787.7 + 62.3 MS, P=0.002) There was a significant increase (SA:30.1 + 2.8 VS 27 + 2.4, P=0.004). In group CM, there was a significant correlation between T1 value and ECV with left ventricular ejection fraction (left ventricle ejection fraction, LVEF) and stroke output (stroke). Damage, and a significant association with LVEF and SV in CM patients,.Mapping technique can increase the sensitivity of CMR diagnosis of myocarditis, which can be used as an effective means for evaluating the progression of myocarditis and evaluating the efficacy of the myocarditis.

【学位授予单位】：山东大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：R445.2;R725.4

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