MRI双向反转恢复序列在心肌瘢痕钆增强成像中延迟血液信号减少的应用

摘要目的研究3.0TMRI上的标准反转恢复(IR)序列相比,双向IR预脉冲在心肌瘢痕钆延时增强检查中是否提高瘢痕-血液对比和专家的诊断信心及一致性。方法这项研究得到当地伦理委员会的批准,所有病人均签署了书面知情同意书。12例有心肌瘢痕的男性病人[平均年龄(63±8)岁]在注射0.2mmol/kg钆布醇10、20和30min后分别使用标准的和双向IR序列进行MR成像。     

3T MR肾脏灌注成像:动脉自旋标记和动态增强技术的对比研究

目的评价3T MR动脉自旋标记和动态增强技术测量肾脏血流量的可行性和两者的相关性。材料与方法研究获机构审查委员会批准,19名健康志愿者(7名女性,12名男性;年龄25～68岁)入组,均签署知情同意书。采用3T     

对28078例钆特醇增强MR成像病人的不良反应率的评估

目的测定应用钆特醇作为常规MR成像对比剂在第3期临床使用情况的不良反应率。材料与方法本研究经机构伦理委员会同意,病人签署知情同意书,符合HIPAA     

改良的延迟钆增强MR成像在植入心脏除颤器病人中的应用

正目的提出并测试改良宽带的延迟钆增强(LGE)MR成像在去除植入心脏除颤器病人中高信号伪影的效果。材料与方法本研究经机构审查委员会批准并符合HIPAA     

肝细胞癌病灶特征:单中心MR系统改善前后,多期钆增强MR成像临床诊断效能的回顾性对照研究

目的评价最新技术和多期钆增强MRI检测肝细胞肝癌(HCC)的诊断效能,并与本机构前期研究结果对照。材料与方法本回顾性研究获得当地伦理委员会同意。病人均签署了知情同意书。2008年1月—2010年4月,101例病人     

去神经化和神经再支配骨骼肌的连续性MR成像与功能结果的相关性

摘要目的前瞻性评估病人的去神经化和神经再支配骨骼肌的短反转时间反转恢复(STIR)MR信号强度随时间出现的变化。材料与方法本研究得到了机构评审委员会的支持,所有病人均签署了知情同意书。23例前臂正中神经或尺神经创伤性横断伤病人,外科神经修补术后接受了前瞻性的12个月随访,神经修补后1、3、6、9、12个月采集选择性手部肌肉内的STIRMR影像,半定量分析去神经化以及神经再支配的肌肉信号强度。     

心肌灌注MR成像收缩期与舒张期采集的比较

目的比较收缩期与舒张期心肌血流量(MBF),并确定两期对可疑冠状动脉疾病(CAD)病人诊断的准确性。材料与方法此项研究经本地区伦理委员会批准,并且所有病人签署知情同意书。接受冠状动脉成像后,40例病人[男27例,平均(64±8)岁]采用1.5TMR设备行应力及静息态MR     

由MR成像数据计算机自动生成的前列腺体积:影像学医师利用MR成像计算体积和病理标本体积的对比

目的以病理标本作为参考标准,比较3TMR成像自动计算多功能活动形状模型(MFA)的前列腺体积(PV)与其他方法评估的前列腺体积。材料与方法本研究符合HIPAA法案,获得机构审查委员会批准,所有受试者均签署了知情同意书。91例病人(42~84岁,平均59岁)新鲜切除的     

CO中毒后迟发性帕金森症:应用反转恢复MR成像评价黑质

摘要目的应用灰质(GM)抑制反转恢复序列(IR)MRI定量研究CO中毒后迟发性帕金森症病人的黑质信号改变。材料与方法本前瞻性研究经当地伦理审查委员会批准且所有受试者均签署知情同意书。     

联合钆和超顺磁性氧化铁对比剂MR增强成像评估多发性硬化的活动性

摘要目的应用钆和超微超顺磁性氧化铁(USPIO)颗粒作为对比剂,比较多发性硬化病变随时间变化的MR成像特征。方法该研究获得当地伦理委员会批准,所有受试者签署知情同意书。对24例多发性硬化病人(10例复发型、14例进展型)给予钆和USPIO增强MRI检查并随访6个月。采用Pearsonχ2或Fisher确切检验比较单独使用钆增强强化的病变、USPIO增强强化的病变及两者都强化的病变数量,用U检验比较病变大小。     

Acute, subacute, and chronic myocardial infarction: quantitative analysis of gadolinium-enhanced MR images

The value of gadolinium enhancement to enable detection of infarcted myocardium at T1-weighted magnetic resonance (MR) imaging was assessed in 84 patients after acute myocardial infarction (AMI). Five healthy subjects served as controls. All patients underwent MR imaging before and 20 minutes after administration of gadopentetate dimeglumine. Contrast enhancement of normal myocardium varied 7% +/- 4 after administration of gadopentetate dimeglumine. Mean intensity ratio after gadolinium enhancement in group 1 (imaging less than 1 week after AMI), group 2 (imaging 1-3 weeks after AMI), and group 3 (imaging 3-6 weeks after AMI) was significantly higher than before gadolinium enhancement. In group 4 (imaging more than 6 weeks after AMI), no significant difference was observed. After gadolinium enhancement, the intensity ratio was abnormally increased in 82% of the MR examinations in group 1, in 62% of group 2, in 58% of group 3, and in 12% of group 4. Gadolinium enhancement improved visualization of myocardial infarction at MR imaging up to 6 weeks after onset of symptoms and had a maximal effect within 1 week after AMI.     

Cardiac MRI left ventricular global function index and quantitative late gadolinium enhancement in unrecognized myocardial infarction

PurposeTo compare left ventricular global function index (LVGFI) and quantitative late gadolinium enhancement (LGE) in patients with unrecognized myocardial infarction (UMI), recognized myocardial infarction (RMI) and without myocardial infarction (MI).Material and methodsUnder waiver of the Institutional Review Board 235 patients (age 63.5 ± 10.5 years, 57 female) were retrospectively evaluated. All patients had undergone cardiac MRI at 1.5T for symptoms of CAD. 67 patients (29%) had suffered a known RMI before. Functional imaging and full-intensity late gadolinium enhancement (LGE) imaging were evaluated for LVGFI and quantitative LGE mass.ResultsOf 168 patients without history of RMI, 48 patients (29%) had UMI, 120 patients had no MI. LVGFI was lower in RMI patients (34 ± 8% [range 16;52]), and UMI patients (35 ± 8% [range 10;51]), compared to patients with no MI (38 ± 7% [range 16;55]) respectively and similar between RMI and UMI patients. RMI patients had full-intensity LGE in 11 ± 6% of left ventricular myocardial mass (LVMM). UMI patients had LGE in 9 ± 5% of LVMM. RMI patients had significantly more LGE than UMI patients (p = 0.0096).ConclusionLGE quantification is effective to assess infarction scar size in RMI and UMI patients. LVGFI provides information on cardiac function and morphology but does not allow for a reliable differentiation between patients with and without history of MI, due small differences and wide overlap of LVGFI values for all three patient groups. This may be a reason why LVGFI is not applied in clinical routine.     

Acute myocardial infarction: evaluation with first-pass enhancement and delayed enhancement MR imaging compared with 201Tl SPECT imaging

PURPOSE: To evaluate acute myocardial infarction by using first-pass enhancement (FPE) and delayed enhancement (DE) magnetic resonance (MR) imaging compared with thallium 201 ((201)Tl) single photon emission computed tomography (SPECT). MATERIALS AND METHODS: Contrast material-enhanced FPE MR, inversion-recovery DE MR, and rest-redistribution (201)Tl SPECT images were obtained in 60 consecutive patients (53 men, seven women; mean age [+/- SD], 56 years +/- 13; range, 30-78 years) at 6 days +/- 3 after reperfused first myocardial infarction. Presence of microvascular obstruction was determined on FPE MR images. Infarct size was defined on DE MR images as percentage of left ventricular (LV) area and compared with uptake defect on redistribution (201)Tl SPECT images. Differences in continuous data were analyzed with Student t test. Linear regression and Bland-Altman analysis were used to compare measurements of infarct size. RESULTS: Mean infarct size was not significantly different between DE MR imaging (20.7% +/- 11.5% of LV area) and (201)Tl SPECT (19.4% +/- 14.3% of LV area; P =.26); good correlation (r = 0.73; P <.001) and agreement were found, with a mean difference of +1.3% +/- 9.8% of LV area. (201)Tl SPECT failed to depict infarct in six (20%) of 30 patients with inferior myocardial infarction (mean size, 6.4% +/- 5.7% of LV area on DE MR images), whereas DE MR images showed the infarct in all patients (P <.01). FPE MR images depicted microvascular obstruction in 23 (38%) of 60 patients; these patients had larger infarctions at DE MR imaging than did patients without microvascular obstruction (30.4% +/- 9.0% vs 15.1% +/- 8.4% of LV area, P <.001). (201)Tl SPECT showed larger infarcts in patients with microvascular obstruction (26.7% +/- 16.2% vs 15.0% +/- 11.2% of LV area, P <.01). CONCLUSION: Good correlation and agreement with (201)Tl SPECT indicate DE MR imaging may be used to estimate infarct size 6 days after reperfused acute myocardial infarction. DE MR imaging is more sensitive for detection of inferior infarction than is (201)Tl SPECT. Patients with microvascular obstruction on FPE MR images have larger infarcts.     

肥厚性心肌病:对比剂增强心血管MRI延迟强化定量分析

目的确定重复性最好的半自动灰阶阈值技术对大样本肥厚性心肌病(HCM)病人钆延迟强化(LGE)的定量。材料与方法研究由参与机构的内部审查委员会核准,所有     

Acute myocardial infarction: comparison of T2-weighted and T1-weighted gadolinium-DTPA enhanced MR imaging

Magnetic resonance images were obtained from 32 patients with acute myocardial infarction, using a four-echo technique (echo time (TE) = 30, 60, 90, and 120 ms) pregadolinium(Gd)-DTPA injection and a TE = 30 ms sequence pre- and post-Gd-DTPA. Intensity ratios of infarcted and normal myocardium were calculated, as were contrast-to-noise and signal-to-noise ratios. The four intensity ratios pre-Gd-DTPA were 1.20 +/- 0.15, 1.42 +/- 0.22, 1.78 +/- 0.38, and 1.99 +/- 0.60 for TE = 30, 60, 90, and 120 ms, respectively, and 1.42 +/- 0.19 post-Gd-DTPA (p = NS for post-Gd-DTPA vs TE = 60, p = 0.007 for TE = 90 vs TE = 120, p less than 0.0001 for all other comparisons). The four contrast-to-noise ratios pre-Gd-DTPA were 1.69 +/- 0.97, 2.69 +/- 1.13, 3.17 +/- 1.15, and 2.90 +/- 1.09 for TE = 30, 60, 90, and 120 ms, respectively, and 2.71 +/- 1.26 post-Gd-DTPA (p = NS for post-Gd-DTPA vs TE = 60, 90, and 120, p = NS for TE = 120 vs TE = 60 and 90, p less than 0.01 for all other comparisons). The four signal-to-noise ratios pre-Gd-DTPA were 8.67 +/- 1.47, 6.52 +/- 0.76, 5.20 +/- 0.64, 4.17 +/- 0.53 for TE = 30, 60, 90, and 120 ms, respectively, and 9.17 +/- 1.92 post-Gd-DTPA (p = 0.03 for post-Gd-DTPA vs TE = 30, p less than 0.0001 for all other comparisons). In conclusion, the detectabilities of acute myocardial infarction were similar at TE = 60 ms and at Gd-DTPA enhanced short-TE MR imaging. However, image quality proved to be superior using the Gd-DTPA enhanced short-TE technique.