肺动脉血栓栓塞的MRI诊断价值

目的探讨肺动脉血栓栓塞（ＰＥ）ＭＲＩ诊断的价值和限度。方法２８例患者［男１７例,女１１例,平均（４１．１±１５．６）岁］行ＭＲＩ检查,其中急性期７例,慢性期２１例。应用心电图门控自旋回波（ＳＥ）、梯度回波（ＧＲＥ）和时间飞跃（ＴＯＦ）法二维ＭＲ血管造影（ＭＲＡ）技术。结果２４例中心型ＰＥ患者在扩张的肺动脉内显示栓子：Ｔ１ＷＩ呈中等信号或中等度高信号,Ｔ２ＷＩ均呈高信号,ＧＲＥ电影ＭＲＩ显示栓子呈中等或低信号,ＭＲＡ可见肺动脉内不规则形、中等信号的充盈缺损。４例周边型ＰＥ患者,ＭＲＩ显示肺内靠近胸膜处有斑片状异常信号。ＰＥ的继发异常征象有：右心室扩大、室壁运动减弱,伴三尖瓣返流,室间隔僵直,凸向左心室侧,左心房室缩小,主肺动脉显著扩张等。慢性期患者右心室壁均明显增厚,达（８．０±１．７）ｍｍ,而急性期无此改变。结论ＭＲＩ可准确作出中心型ＰＥ的诊断,但是周围型ＭＲＩ所见与慢性阻塞性肺心病难以鉴别,为ＭＲＩ的不足之处。     

亚急性和慢性心肌梗塞的MRI诊断和评价

目的：确定自旋回波（ＳＥ）和电影动态ＭＲＩ（ｃｉｎｅＭＲＩ）评价亚急性和慢性心肌梗塞信号变化、室壁节段运动和其他合并症的价值。材料和方法：对心肌梗塞亚急性期５例和慢性期１３例进行ＭＲ横断面、左室长／短轴Ｔ１ＷＩ，其中１３例还经Ｔ２ＷＩ，５例经Ｇｄ－ＤＴＰＡ增强。结果：前壁（包括前间壁）受累６例，下壁、侧壁和后壁受累各２例，前壁和下壁均受累６例。Ｔ１ＷＩ显示４例梗塞室壁信号略低，４例亚急性期注射Ｇｄ－ＤＴＰＡ后强化，慢性期１１例室壁厚度变薄；ｃｉｎｅＭＲＩ显示１５例室壁节段运动减低；发现合并二尖瓣返流６例、主动脉瓣返流４例、心包积液４例。结论：ＳＥ和ｃｉｎｅＭＲＩ能较好地显示心肌梗塞的部位、范围和室壁厚度，ｃｉｎｅＭＲＩ评价室壁节段运动和瓣膜返流更具优势     

高场磁共振仪评估新生儿和婴儿的正常脑髓鞘

目的：应用高场ＭＲ仪研究正常小儿不同月龄段的脑髓鞘与对应ＭＲＩ信号特征。方法：５８例正常小儿在１．５Ｔ ＭＲ仪内行头部扫描。采用自旋回波（ＳＥ０和快速自旋回波（ＴＳＥ）序列,获取Ｔ１和Ｔ２架驻像,结果：（１）髓鞘形成中的ＭＲＩ信号变化,相对于灰质信号,未的髓鞘呈短Ｔ１和长Ｔ２,在Ｔ１ＷＩ上呈高信号与灰质易区别,在Ｔ２ＷＩ上与灰质信号相近;的髓鞘呈短Ｔ１和短Ｔ２;在Ｔ２ＷＩ上呈低信号,与灰质易区别;     

子宫良性肿瘤的MRI检查和诊断

目的：分析各种子宫良性肿瘤ＭＲＩ 图像,探讨ＭＲＩ 在子宫良性肿瘤中的诊断价值。材料和方法：共收集本院１９９４ － １９９９ 年临床疑子宫良性肿瘤病人３９ 例。ＭＲＩ 检查在ＧＥ Ｖｅｃｔｒａ０ ．５Ｔ 和ＧＥｓｉｇｎａ Ｈｏｒｉｚｏｎ１ ．５Ｔ 超导成像仪上进行,采集矢状面ＦＳＥ Ｔ２ ＷＩ 像,横断面ＳＥ Ｔ１ ＷＩ 像和ＦＳＥ Ｔ２ ＷＩ 像,并对各种病变所致子宫和宫颈的位置、大小、外形与其各层结构变化进行仔细观察和分析,与手术病理对照,以确定ＭＲＩ 的诊断价值。结果：３９例ＦＳＥ Ｔ２ ＷＩ 图像均清晰显示子宫及宫颈诸层结构;矢状面更可清楚显示子宫位置和大小。３９ 例病变均经病理证实,２３ 例为子宫肌瘤,子宫形态均增大,连结层和内膜层可受压,其中１７ 例Ｔ１ ＷＩ 和Ｔ２ ＷＩ 上表现为低信号影,６ 例为低到高不均匀信号影。１２ 例为子宫腺肌瘤,Ｔ２ ＷＩ 上连结层结构不清及较低信号,且增厚。１ 例为纳氏囊肿,Ｔ１ ＷＩ 上为子宫颈后壁内低信号囊状影,边缘光滑,Ｔ２ ＷＩ 上为均匀高信号影。本组有１ 例多发性肌瘤出血ＭＲＩ 上被误诊为子宫腺肌瘤;有２ 例子宫浆膜下肌瘤似游离于盆腔内,而漏诊。结论：ＭＲＩ 横断面及矢状面ＦＳＥ Ｔ２ ＷＩ 能清晰显示     

颈动脉体瘤的MRI和MRA表现

目的 探讨颈动脉体瘤的ＭＲＩ及ＭＲＡ表现。材料与方法 １３例１５个颈动脉体瘤术前ＳＥＴ１ＷＩ检查,其中行２ＤＴＯＦ ＭＲＡ检查者１２个,ＳＥＴ１ＷＩ增强检查者１０个。结论 １５个颈动脉体瘤均位于颈动脉分叉水平,１３个骑跨于颈动脉分叉（８６．６６％）。Ｔ１ＷＩ表现为等或略高信号,Ｔ２ＷＩ表现为混合高信号。ＳＥＴ１Ｗ１３个肿块内可见流空信号（８６．６６％）,ＦＳＥ Ｔ２ＷＩ均可见流空信号（１００％）。     

心内膜心肌纤维化症的影像诊断

目的　探讨心内膜心肌纤维化症 (EMF)的影像诊断价值。方法　回顾分析 2 8例EMF影像学表现。结果　右室型 2 1例 ,左室型 1例 ,双室型 6例。平片对本病误诊率较高 ,误诊为 18/ 2 8例 ;造影及MRI均能显示右心型右室流入道变小、缩短 ,边缘不整 ,心尖闭塞 ,流出道扩张 ,三尖瓣大量返流 ,右房巨大 ,上腔静脉扩张。左室型表现为左室流出道狭窄、边缘不规则 ,室腔变形变小 ,收缩与舒张期无明显变化 ,心尖圆钝 ,二尖瓣返流。双室型表现为左右室型的特点 ,但以右室型表现为主。结论　X线平片对本病的诊断价值有限 ,造影及MRI检查均能确诊本病 ,而MRI为无创安全的检查可取代造影成为首选检查方法     

强直性脊柱炎骶髂关节影像学分析：附24例骶髂关节平片,CT和MR…

目的：旨在评估强直性脊柱炎（ＡＳ）患者骶髂关节炎的ＭＲ影像特征，并比较Ｘ线平片、ＣＴ和ＭＲ影像在诊断骶髂关节炎中的作用。材料与方法：搜集２４例ＡＳ患者，分别行Ｘ线平片、ＣＴ和ＭＲＩ检查。增强前ＭＲ扫描序列包括ＳＥ Ｔ１ＷＩ、ＦＳＥ Ｔ２ＷＩ和梯度回波的准Ｔ２ＷＩ（ＧＲ Ｔ２＾＊ＷＩ）。增强后ＭＲ扫描序列参数与增强前ＳＥ Ｔ１ＷＩ相同。另选９例志愿者，行ＭＲ平扫检查。结果：８例志愿者１６个骶髂关节的     

鼻咽癌放射治疗后脑干放射性损伤的MRI表现

目的探讨鼻咽癌放射治疗后脑干放射性损伤的ＭＲＩ表现。方法分析５１例鼻咽癌经放射治疗后，脑干放射性损伤的ＭＲＩ自旋回波Ｔ１ＷＩ及超快速自旋回波Ｔ２ＷＩ和增强后Ｔ１ＷＩ表现及临床表现。结果脑干放射性损伤的临床表现为肢体麻木、无力或瘫痪及颅神经损伤症状。ＭＲＩ显示中脑、脑桥和延髓内呈斑片状改变分别为２、７及３例；脑桥基底部广泛受累９例；脑桥基底部下份及延髓前上份者３０例。自旋回波Ｔ１ＷＩ病灶均呈低或等信号改变；超快速自旋回波Ｔ２ＷＩ呈等、高信号混杂改变，脑桥水平病灶内高信号呈横行条纹状。增强后扫描显示病灶区无强化者９例，斑点状强化者３例及不规则花环状强化者３９例。占位效应与病灶的大小不相称。１４例经治疗后ＭＲＩ复查，４例病灶消失，８例病灶形态及位置无变化，２例病灶增大。结论ＭＲＩ可显示脑干放射性脑病特征；临床症状与ＭＲＩ追踪表现可不完全一致     

缩窄性心包炎磁共振成像的诊断研究

目的评价ＭＲＩ对缩窄性心包炎的诊断和鉴别诊断价值及其限度。材料与方法２６例经临床资料、心电图、Ｘ线和（或）手术证实的缩窄性心包炎患者，行心电图门控ＳＥ和ＧＥ电影ＭＲＩ扫描，ＭＲＩ所见与３０例正常成人志愿者行对比分析。结果缩窄性心包炎的主要ＭＲＩ征象有：心包脏壁层界限不清，呈不规则增厚（厚度＞４ｍｍ），以右心房室侧多见；增厚的心包呈中等信号或中等度低信号，内部信号不均，其中可有斑状极低信号或高信号；室间隔僵直，心室内径缩小，室壁运动减弱；右心房扩大，上下腔静脉扩张，少数病例左心房扩大，肺静脉扩张；可合并房室瓣少至中等量返流。结论ＭＲＩ很容易确定缩窄性心包炎的心包增厚，具有诊断和鉴别诊断的价值，但其价格昂贵、对钙化不敏感为其主要限度。     

快速序列动态增强MRI对前列腺癌的诊断价值

目的 研究快速成像序列动态增强对前列腺癌的检出和定性价值。方法 对经活检证实的２５例,临床证实的６例,共３１例前列腺癌患者作了前瞻性增强ＭＲＩ研究。先行ＳＥＴ１ＷＩ、快速自旋回波（ＦＳＥ）Ｔ２Ｗ序列扫描,然后行快速多怪面干扰梯度回波（ＦＭＰＳＰＧＲ）序列团注增强扫描,共４个回合,研究病灶增强情况,并对增强后图像与常规ＦＳＥＴ２ＷＩ进行比较。结果 ＦＭＰＳＰＧＲ增强后扫描,共发现病灶２９个,可疑病灶     

致心律不齐性右室心肌病的MRI诊断

目的：用心脏MR新技术评价致心律不齐性右室心肌病（ARVC）的MRI征象，探讨MR扫描技术。方法：对15例临床、超声诊断或疑为ARVC的病人进行RM检查，使用GE Signa1.5TCV/iMR扫描系统，扫描序列包括黑血技术：双反转恢复快速自旋回波(double-IR FSE)和三反转自旋回波（triple-IR FSE）序列；白血技术：快速电影成像（fastcine）序列。扫描平面有短轴面、四腔面和长轴面。结果：10例诊断为ARVC，ARVC的主要MRI表现有：右室壁脂肪信号3例，右室壁变薄9例，右心室扩大6例，室壁瘤形成2例，右心腔内慢血流信号9例，右室射血分数降低6例，右房扩大3例。右室乳状肌和左室心尖部、室间隔前部累及2例。黑血技术可显示心脏解剖、形态及组织特性，白血技术主要了解心脏功能及心肌壁的运动，短轴面和四腔面显示病变较满意。结论：ARVC的RMI表现具有一定的特征，多序列、多平面成像的MR新技术对该病的诊断更准确、更可靠。     

磁共振多技术联合应用检测存活心肌的实验研究

目的　评估磁共振多技术联合应用检测心肌存活的价值。材料与方法　选择慢性心肌缺血模型猪 2 0只 ,分别于制作模型前、后 1～ 2个月行磁共振多技术联合应用扫描 (形态、电影扫描、心肌灌注和心肌活性扫描 ) ,判断心肌缺血区和坏死区的大小 ,并与病理结果对照了解其准确性。结果　MRI检查发现 2 0只猪中有 3只形态扫描见左室侧壁变薄 ;负荷电影扫描见 11(11/2 0 )只猪左心室收缩功能正常 ,有 9(9/2 0 )只静息时左室节段不同程度运动减弱 (n =7)或丧失 (n =2 )。多巴酚丁胺负荷电影扫描检测到 7只猪左室节段功能改善 ,但有 2只猪无明显改善。心肌灌注扫描有 13只猪共 4 7.8个节段缺血 ,心肌活性扫描有 8只猪共 2 3.6个节段坏死 ,病理检查发现共有 7只猪 2 3个节段坏死。与MRI延迟强化区所显示的梗死区一致 ,差异无统计学意义 (t=0 .0 4 5 ,P >0 .0 5 )。结论　磁共振多技术联合应用可有效检出缺血、坏死心肌 ,并准确判断其程度和范围     

MRI assessment of pacing induced ventricular dyssynchrony in an isolated human heart

This study demonstrates the capabilities of MRI in the assessment of cardiac pacing induced ventricular dyssynchrony, and the findings support the need for employing more physiological pacing. A human donor heart deemed non‐viable for transplantation, was reanimated using an MR compatible, four‐chamber working perfusion system. The heart was imaged using a 1.5T MR scanner while being paced from the right ventricular apex (RVA) via an epicardial placed lead. Four‐chamber, short‐axis, and tagged short‐axis cines were acquired in order to track wall motion and intramyocardial strain during pacing. The results of this study revealed that the activation patterns of the left ventricle (LV) during RVA pacing demonstrated intraventricular dyssynchrony; as the left ventricular mechanical activation proceeded from the septum and anterior wall to the lateral wall, with the posterior wall being activated last. As such, the time difference to peak contraction between the septum and lateral wall was ～125 msec. Likewise, interventricular dyssynchrony was demonstrated from the four‐chamber cine as the time difference between the peak LV and RV free wall motion was 180 msec. With the ongoing development of MR safe and MR compatible pacing systems, we can expect MRI to be added to the list of imaging modalities used to optimize cardiac resynchronization therapy (CRT) and/or alternate site pacing. J. Magn. Reson. Imaging 2010; 31: 466–469. © 2010 Wiley‐Liss, Inc.     

Accurate quantification of right ventricular mass at MR imaging by using cine true fast imaging with steady-state precession: study in dogs

PURPOSE: To assess the accuracy of cine magnetic resonance (MR) imaging with a segmented true fast imaging with steady-state precession (FISP) technique for right ventricular (RV) mass quantification. MATERIALS AND METHODS: Fourteen dogs were imaged with a 1.5-T clinical MR imaging unit by using an electrocardiographically gated true FISP sequence. Contiguous segmented k-space cine images were acquired from the base of the RV to the apex during suspended respiration (repetition time msec/echo time msec, 3.2/1.6; section thickness, 5 mm; in-plane resolution, 1.0 x 1.3 mm2). After imaging, each dog was sacrificed, and the RV free wall was isolated and weighed. Each MR imaging data set was analyzed twice by each of two independent observers who were blinded to the results of RV mass measurement at autopsy, and the mass measurements at MR imaging were compared with the autopsy results by using linear regression and Bland-Altman analysis. RESULTS: RV mass measurements calculated by using the true FISP cine MR images were nearly identical to those at autopsy (R = 0.82, standard error of the estimate = 1.7 g, P >.05), with a mean difference between the autopsy and MR imaging measurements of 0.3 g +/- 1.7 (1.9% +/- 8.2) (P >.05). Inter- and intraobserver variations were small, with a mean interobserver variability of -0.1 g +/- 2.3 and a mean intraobserver variability of 0.2 g +/- 1.6 at every-section analysis. CONCLUSION: In this animal model, true FISP cine MR imaging enabled accurate quantification of RV mass.     

磁共振成像对心膜心肌纤维化症的诊断价值

目的 探讨MRI对心内膜心肌纤维化症（EMF）的诊断价值。材料与方法 选择经超声、心血管造影或／或病理证实的10例EMF进行MRI平扫及电影MRI检查,测量各径线及心脏功能,分析心脏及室壁情况,对比3种检查方法对EMF的诊断价值。结果 右室型7例,MRI均见右室流入缩短、变形、心尖闭塞,流出道及主肺动脉扩张,右房高度扩张,右室壁运动普遍减弱,其中2例并发右房血栓。双室型3例除见右室型表现外,尚有左房扩张,左室心尖闭塞,左室功能受损。经测量右室流出道、右房、主肺动脉径线,MRI、右房造影及超声检查三者无差异。结论 MRI对EMF的诊断有独到的优越性。对EMF的检查应道选超声及MRI,必要时才选用X线心血管造影。     

Cine magnetic resonance with dobutamine following a myocardial infarct

PURPOSE: Dobutamine cine MRI is a new diagnostic imaging technique in the pretreatment (revascularization) assessment of myocardial infarction patients. We report the results of a comparative study of the diagnostic yield of dobutamine cine MRI with that of stress echocardiography in the assessment of viable myocardium. We also propose a new method for analysis of cine MR images, employing digital subtraction, aimed at decreasing subjectivity in the quantitative assessment of myocardial wall thickening. MATERIAL AND METHODS: Twenty-six patients (21 men and 5 women) with a history of myocardial infarction who were scheduled for revascularization were submitted to stress echocardiography and dobutamine cine MRI to evaluate contractile recovery of the segments considered akinetic or hypokinetic at baseline echocardiography. Dobutamine was administered in growing doses (5, 10, 15 gamma/kg/min). We considered 16 segments of the left ventricle in each patient. We performed a quantitative analysis of systolic wall thickening on individual cine MR frames both by manual measurements and by digital subtraction. RESULTS: In the 416 segments studied, we found 307 normokinetic, 64 scarred and 45 viable segments with stress echocardiography, versus 302 normokinetic, 83 scarred and 31 viable segments with dobutamine MRI. Wall thickening analysis on Cine MR images showed 268 normal, 68 scarred and 80 viable segments, versus 274 normal, 58 scarred and 84 viable segments with digital subtraction. Three months after revascularization 15 patients were examined to check contractile recovery of the segments considered as viable. Echocardiography had 79% sensitivity and 97% specificity, while cine MRI had 96% and 86%, respectively. Quantitative assessment of systolic wall thickening by cine MRI and digital subtraction had 96% sensitivity and 91% specificity, with no statistically significant differences between the two techniques. In patients with anteroseptal wall myocardial infarction stress echocardiography had 75% sensitivity and 97% specificity. In the subgroup of 13 patients with diaphragmatic or inferior wall infarction echocardiography sensitivity dropped to 68%, versus 96% of cine MRI, but its specificity was higher, namely 97 versus 86%. CONCLUSIONS: In anteroseptal infarction, echocardiography permits to distinguish viable myocardium and scarred myocardial tissue with good sensitivity and specificity, but cine MRI performs better. In inferolateral or diaphragmatic infarction, cine MRI has much higher sensitivity than stress echocardiography and thus makes the technique of choice to evaluate viable myocardium in these sites. The digital subtraction technique is as accurate as manual measurements, but reduces the error rate and permits quicker evaluation, particularly in subendocardial thickening.     

中国人心脏房室腔内径及左右心室功能正常参数的MRI研究

目的 使用MRI测量中国正常成人心脏各房室腔内径及心功能参数.方法 共269名正常志愿者,无线矢量心电门控下,采用单次激发半傅立叶快速自旋回波与真实稳态自由进动序列,分别获得标准心脏各长轴及短轴切面二维体层及电影图像.由2名医师独立分析MRI,分别测量心脏各房室腔径线及心功能后处理分析,获得包括射血分数(EF)、舒张末容积(EDV)、收缩末容积( ESV)及心肌质量(CM)等心功能参数.男性与女性相对应参数做非配对的t检验.结果 所有志愿者均完成MR扫描,平均扫描时间(15 ±3) min.心脏各房室腔主要参数为:左心房前后径(2.87±0.77) cm,右心房径(垂直于房间隔,3.61 ±0.57)cm,左心室舒张末横径(4.97±0.52) cm,右心室舒张末横径(2.65±0.48) cm,心功能主要参数为:左心室EF (60.62±7.08)％、EDV( 128.27±32.16) ml、ESV(46.02±15.72) ml、CM( 82.97±24.03)g;右心室EF (47.73±6.50)％、EDV(115.37±26.71) ml、ESV(67.7±21.07) ml、CM(48.24±13.42)g.除左心室ESV(P =0.144)、EDV指数(P=0.714)、ESV指数(P =0.113)、心脏指数(P=0.199)及右心室EF值(P=0.296)和ESV指数(P =0.093)男女差异无统计学意义外,其余各指标性别间差异均有统计学意义(P＜0.01).结论 MRI以其高度的可重复性可获得正常中国人心脏形态与功能信息.     

Severity of aortic regurgitation: interstudy reproducibility of measurements with velocity-encoded cine MR imaging.

The interstudy reproducibility of velocity-encoded cine (VEC) magnetic resonance (MR) imaging for quantification of regurgitant volume (RV) and regurgitant fraction (RF) was studied in 10 patients with chronic aortic regurgitation. Each patient underwent two VEC MR imaging studies. RV and RF were measured on the aortic flow curve by quantifying antegrade and retrograde flow per cardiac cycle. VEC MR imaging measurements for RV and RF correlated closely with volumetric measurements for both studies (r greater than .97). Interstudy reproducibility for VEC MR imaging measurement of RV and RF was high (r greater than .97), and the interstudy variability for VEC MR imaging measurements was low. These results demonstrate a high accuracy of VEC MR imaging for measurement of RV and RF in patients with chronic aortic regurgitation. The level of interstudy reproducibility of VEC MR imaging for quantitative assessment of RV and RF indicates the potential of this technique for follow-up and monitoring of response to therapy.