轻度狭窄与无狭窄颈动脉斑块高分辨率MRI特征

目的 探讨脑血管病患者轻度狭窄或无狭窄颈动脉粥样硬化（AS）斑块的高分辨率MRI（HRMRI）特征。方法 对103例近期出现脑血管病症状且伴颈动脉AS斑块的患者行颈动脉HRMRI。排除图像质量差或颈动脉严重狭窄（狭窄程度≥50%）者。对颈动脉斑块进行定性和定量分析,比较无狭窄（无狭窄组）与轻度狭窄（轻度狭窄组,狭窄程度1%～49%）颈动脉AS斑块的负荷及成分特征差异。结果 最终86例患者共155支颈动脉血管纳入研究,轻度狭窄组24支,无狭窄组131支。无狭窄与轻度狭窄组颈动脉管腔面积[（53.40±15.29）mm² vs （41.30±11.57）mm², P<0.001]和最大管壁厚度[（2.16±0.90）mm vs （3.30±1.25）mm, P=0.014]差异均有统计学意义,而管壁面积[（31.69±6.80）mm² vs （32.80±9.33）mm², P=0.581]差异无统计学意义。无狭窄组和轻度狭窄组存在中度风险斑块、高风险斑块者分别占10.69%（14/131）、6.11%（8/131）和20.83%（5/24）、20.83%（5/24）。颈动脉最大管壁厚度与管腔狭窄程度之间呈正相关（r=0.430,P<0.001）。结论 无狭窄或轻度狭窄的颈动脉血管仍存在发生不稳定斑块的风险。     

高分辨率MRI评估早期颈动脉粥样硬化患者双侧颈动脉分叉几何形态差异

目的 采用颈动脉高分辨MRI评估早期颈动脉粥样硬化患者左右侧颈动脉分叉几何形态的差异。方法 对92例早期颈动脉粥样硬化患者采集颈动脉管壁高分辨MRI，观察双侧颈动脉管壁厚度及斑块分型，计算并比较左右侧颈动脉分叉几何参数的差异。结果 左侧颈动脉管壁厚度[1.24（1.09，1.46）mm]与右侧[1.29（1.10，1.57）mm]差异无统计学意义（Z=－1.12，P=0.26）；左右侧斑块分型差异无统计学意义（P=0.22）。左侧颈内动脉（ICA）平面角（Z=－2.69）、近端面积比（Z=－3.43）、颈总动脉（CCA）扩张面积比（Z=－2.87）、ICA₅~CCA₃弯曲度（Z=－3.17）及二维CCA弯曲度（Z=－2.14）均大于右侧（P均<0.05）；左右侧颈动脉分叉角（Z=－1.23）、ICA角（Z=－8.89）差异无统计学意义（P均>0.05）。结论 早期颈动脉粥样硬化患者左右侧颈动脉分叉几何结构存在显著差异，可能导致左右侧颈动脉斑块发生率不同。     

3D-T2-FFE序列在腰骶丛神经成像中的应用

目的 探讨三维T2加权快速梯度回波（3D-T2-FFE）图像对显示腰骶丛神经的应用价值。方法 收集腰骶丛神经病变患者29例，行常规腰骶椎MRI后加扫3D-T2-FFE及MR选择性水激励脂肪抑制技术（MR-PROSET）序列成像。测量并计算2个序列图像的神经信噪比（SNR_神经）、肌肉SNR（SNR_肌肉）、对比噪声比（CNR_{神经/肌肉}），比较2个序列图像对腰骶丛神经病变的诊断效能。结果 所有病例3D-T2-FFE图像CNR（0.21±0.08）高于MR-PROSET图像（0.11±0.04，P<0.01），SNR_肌肉（66.99±24.62）低于MR-PROSET（108.92±42.28，P<0.01），SNR_神经（150.34±14.98）与MR-PROSET图像（138.02±11.17）差异无统计学意义（P>0.05）；3D-T2-FFE图像显示骶丛、股神经、闭孔神经的评分 （2.32±0.13、1.63±0.60、1.84±0.38）均高于MR-PROSET图像（1.95±0.14、0.11±0.32、1.16±0.38，P均<0.05），而腰丛、腰骶干、坐骨神经的评分（2.95±0.05、1.79±0.42、1.84±0.09）与MR-PROSET图像差异均无统计学意义（2.79±0.42、1.63±0.50、1.74±0.10，P均>0.05）。结论 3D-T2-FFE序列图像可有效评估腰骶丛神经病变，为临床提供更客观、准确的信息。     

超声评价放疗对颈动脉溃疡斑块形成的影响

目的 探讨超声在评价放疗对颈动脉溃疡斑块形成的影响的价值。方法 回顾性收集经病理学证实为头颈部肿瘤、放疗前后的颈动脉超声资料以及其他基线资料完整的患者93例,比较放疗前后放疗侧颈动脉和非放疗侧颈动脉粥样硬化斑块和溃疡斑块的总数量、平均内膜-中膜厚度、最大斑块面积、最大溃疡斑块的面积、最大溃疡口的面积。结果 放疗前后颈动脉超声检查的平均间隔时间为（6.1±1.9）年;放疗前放疗侧斑块总数量、平均内膜-中膜厚度、最大斑块面积、溃疡斑块的总数量、最大溃疡斑块的面积、最大溃疡口的面积与非放疗侧比较差异均无统计学意义（P均>0.05）;放疗后放疗侧斑块总数量、平均内膜-中膜厚度、最大斑块面积、溃疡斑块的总数量、最大溃疡斑块的面积、最大溃疡口的面积均较非放疗侧加重,差异有统计学意义（P均<0.05）。结论 放疗可导致头颈部肿瘤患者颈动脉粥样硬化斑块的形成和进展,且斑块具有易损性特点。     

基于DANTE预脉冲SPACE MR序列定量评价蛛网膜颗粒

目的 评价基于DANTE预脉冲SPACE定量评价蛛网膜颗粒的价值。方法 纳入头颅影像学检查证实存在蛛网膜颗粒的30例患者，分别进行SPACE序列成像和基于DANTE预脉冲的SPACE序列成像。评价SPACE序列图像和DANTE-SPACE序列图像中静脉窦内和颅板下蛛网膜颗粒分布特征，并进行定量测量，包括最大横截面积、最长径、SNR和CNR。比较两种方法获得各测量指标的统计学差异。结果 采用SPACE序列发现43个蛛网膜颗粒，位于静脉窦内29个，颅板下14个；DANTE-SPACE序列检出45个蛛网膜颗粒，其中位于静脉窦内31个，颅板下14个。SPACE和DANTE-SPACE序列显示蛛网膜颗粒分布特征差异无统计学意义（χ²=0.155，P=0.997）。SPACE和DANTE-SPACE序列测量静脉窦腔内蛛网膜颗粒最大横截面积[（32.55±17.08） mm²，（29.15±16.24） mm²]、最长径[（7.13±2.00） mm，（6.42±1.81） mm]、SNR （88.82±29.57，83.30±32.11）、CNR （45.99±28.57，65.33±30.96）差异均有统计学意义（P均<0.05），测量颅板下蛛网膜颗粒最大横截面积[（21.62±9.01） mm²，（21.83±9.04） mm²]、最长径[（6.74±2.83） mm，（6.66±2.87） mm]、SNR （86.91±35.48，76.82±36.20）、CNR （16.87±6.32，20.07±12.76）差异均无统计学意义（P均>0.05）。结论 基于DANTE预脉冲SPACE序列可有效抑制静脉窦内的慢血流伪影，更精准地显示蛛网膜颗粒。     

实时剪切波弹性成像定量评价颈动脉粥样硬化斑块

目的 应用剪切波弹性成像技术（SWE）定量评估颈动脉粥样硬化斑块软硬度。方法 对183例颈动脉粥样硬化斑块患者行SWE检测,获得不同回声颈动脉粥样硬化斑块的平均、最小和最大弹性模量值,比较不同位置（前壁、后壁和侧壁）的强回声斑块和低回声斑块的弹性模量值。结果 共检出强回声斑块133个,低回声斑块128个;强回声斑块的平均、最小、最大弹性模量值分别为（52.67±14.09）kPa、（40.94±15.94）kPa和（62.39±20.38）kPa,低回声斑块分别为（16.83±6.47）kPa、（10.14±5.82）kPa和（24.76±8.56）kPa,差异均有统计学意义（P均<0.01）。前壁、后壁和侧壁斑块间强回声斑块以及低回声斑块的平均、最小、最大弹性模量值差异均无统计学意义（P均>0.05）;2名操作者测得的弹性模量值的差异无统计学意义（P均>0.05）。结论 SWE可根据弹性模量值评价斑块软硬度,为定量评估动脉粥样硬化斑块提供更多信息。     

超声联合微泡对不同凝龄富血小板血栓和富红细胞血栓的溶栓效果

目的 探讨超声联合微泡对不同凝龄富血小板血栓（PRT）和富红细胞血栓（ERT）的溶栓效果。方法 分别于体外和大鼠体内颈总动脉制备不同凝龄的PRT和ERT。离体及在体实验均分为4组,即离体PRT 3 h组、离体PRT 24 h组、离体ERT 3 h组、离体ERT 24 h组及在体PRT 3 h组、在体PRT 24 h组、在体ERT 3 h组、在体ERT 24 h组;分别于体外循环装置和大鼠颈总动脉血栓模型中进行超声联合微泡溶栓实验,并采集超声图像。行病理组织学检查以验证血栓成分。离体实验主要分析溶栓后管腔横截面积增加百分比及溶栓率,在体实验主要分析溶栓后血管再通率及颈总动脉血流速度。结果 溶栓治疗后,离体及在体实验显示：PRT 3 h组与ERT 3 h组管腔横截面积增加百分比[（121.12±13.21）% vs （130.09±15.34）%]、溶栓率[（39.83±7.09）% vs （42.14±5.17）%]、血管再通率（83.33% vs 91.67%）及颈总动脉血流速度[（0.21±0.02）m/s vs （0.22±0.01）m/s]差异均无统计学意义（P均>0.05）。PRT 24 h组与ERT 24 h组比较、PRT 24 h组与PRT 3 h组比较、ERT 24 h组与ERT 3 h组比较,管腔横截面积增加百分比、溶栓率、血管再通率、颈总动脉血流速度均下降（P均<0.05）。与ERT 24 h组比较,PRT 24 h组管腔横截面积增加百分比、溶栓率、血管再通率及颈总动脉血流速度均下降（P均<0.05）。结论 超声联合微泡对溶解离体及在体大鼠颈总动脉PRT和ERT的效果随血栓凝龄的增加而下降,且以PRT为著。     

FBP、iDose4和IMR重建算法对低剂量双下肢CTA图像质量的影响

目的 探讨滤波反投影（FBP）、混合迭代重建（iDose⁴）和基于模型的迭代重建（IMR）技术对低剂量双下肢CTA图像质量的影响。方法 对56例成年患者行双下肢CTA扫描,分别用FBP、iDose⁴和IMR方法重建,测量下肢各段血管（腹主动脉分叉处、髂总动脉分叉处、股动脉近端、股动脉中段和腘动脉近端）的CT值、图像噪声及对比噪声比（CNR）,并采用4分法对3组图像质量分别进行主观评分。结果 FBP、iDose⁴和IMR重建图像的下肢各段血管平均CT值分别为（511.07±195.05）HU、（492.63±178.74）HU、（487.63±197.20）HU,三者间差异无统计学意义（F=1.175,P>0.05）。图像噪声分别为（76.24±20.85）HU、（39.16±11.75）HU、（13.09±2.55）HU,三者间差异有统计学意义（F=1 460.000,P<0.05）。CNR分别为6.35±3.14、12.97±5.10、33.83±15.85,三者间差异有统计学意义（F=646.122,P<0.05）。图像质量主观评分IMR（3.75±0.46）、FBP（1.39±0.51）、iDose⁴（2.61±0.81）差异有统计学意义（χ²=476.79,P<0.05）,膝关节以上、下段动脉可诊断率IMR（98.66%）明显高于FBP（1.34%）、iDose⁴（56.70%）,差异均有统计学意义（χ²=427.9,P<0.05）。结论 行低辐射剂量双下肢CTA扫描时,相比FBP和iDose⁴,IMR可以显著降低图像噪声,提高图像质量,且能满足诊断要求。     

经导管主动脉瓣置换术前实时三维经食管超声自动测量主动脉瓣环径

目的 探讨经导管主动脉瓣置入术（TAVR）中应用实时三维经食管超声心动图（3D-TEE）自动测量主动脉瓣环的可行性与准确性。方法 对21例拟接受TAVR患者于术前分别采用3D-TEE和多排CT（MDCT）测量主动脉瓣环面积、周长、最大径和最小径。对比3D-TEE测值与MDCT测值间的差异及相关性,记录3D-TEE自动测量主动脉瓣环参数所需的时间。结果 3D-TEE所测主动脉瓣环面积为（445.74±62.60）mm²,周长为（76.16±5.30）mm,最大径为（26.29±1.97）mm,最小径为（21.40±1.68）mm,MDCT测值分别为（456.85±75.70）mm²、（77.17±5.90）mm、（26.76±2.83）mm、（20.98±1.76）mm。MDCT与3D-TEE所测主动脉瓣环面积、周长、最大径及最小径差异均无统计学意义（P均>0.05）。3D-TEE与MDCT所测主动脉瓣环面积、周长、最大径、最小径均呈高度相关（r=0.89、0.91、0.85、0.79,P均<0.01）。采用3D-TEE自动测量主动脉瓣相关径线所需时间为（1.54±0.21）min。结论 3D-TEE自动测量主动脉瓣环能准确、快速获得主动脉瓣环相关径线,可作为替代MDCT的影像学方法。     

全模型迭代重建算法评价125I粒子植入术后CT图像

目的 探讨全模型迭代重建（IMR）算法评价¹²⁵I粒子植入术后图像的应用价值。方法 收集接受¹²⁵I粒子植入术及术后CT随访的16例腹部肿瘤患者,对扫描原始数据分别以滤波反投影法（FBP）、IMR和高级重建迭代（iDose⁴）算法进行重建,比较3种重建方法图像的噪声、伪影指数（AI）、CNR和主观评分。结果 FBP重建图像的噪声、CNR及AI分别为（58.65±4.03） HU、1.09±0.43和51.60±9.23,iDose⁴图像分别为（48.38±5.34） HU、1.29±0.48和43.77±4.91,IMR图像分别为（41.46±3.44） HU、1.58±0.56和38.51±4.64,3种重建方法图像的噪声、CNR及AI两两比较差异均有统计学意义（P均<0.05）。IMR图像的主观图像质量评分显著高于FBP和iDose⁴算法图像（调整后P<0.001,P=0.011）。结论 IMR算法获得的图像质量较高,可有效减少¹²⁵I粒子伪影,为¹²⁵I粒子植入术后随访与疗效评估提供了更佳方法。     

Experimental evaluation of the detectability of submillimeter atherosclerotic lesions in ex vivo human iliac arteries with ultrahigh-field (7.0 T) magnetic resonance imaging

Background To evaluate the ability of ultrahigh-field magnetic resonance imaging (MRI) to accurately depict the composition of the human arterial vessel wall ex vivo and to detect early atherosclerotic lesion formation in comparison to histology. Methods Eight iliac artery specimens with low-grade atherosclerotic lesions obtained from human organ donors were studied. Three-dimensional, high-resolution MRI (spatial resolution: 79 × 79 × 109 μm) was performed using T1-, T2- and proton density (PD)-weightings (7.0 Tesla MR system, Bruker Pharmascan). A total of 36 MR slices and corresponding histological sections were matched for comparative evaluation of area measurements of lumen, media and adventitia and—if present—plaque size. Statistical correlation between histology and MR measurements was tested and a ROC-analysis was performed to determine the plaque size being predictive of correctly identifying atherosclerotic lesions with MRI. Results The areas of vessel lumen and media as measured on T1-, T2- and PD-weighted MR images showed a strong correlation with the corresponding histological measurements (r = 0.84 to r = 0.89; P < 0.01), however, a systematic overestimation of 34–41% was found. For the area of adventitia, only a moderate, though significant, correlation (r = 0.55 to r = 0.62; P < 0.01) could be demonstrated with a similar overestimation by MRI (38–43%). With T1-weighted MRI, sensitivity and specificity for the detection of plaques > 4.0 mm² were 79% and 91%, respectively. With T2- and PD-weighted MRI, however, sensitivity and specificity for the detection of plaques > 0.4 mm² were 93% and 89%. Conclusions In an experimental ex vivo setting, ultrahigh-field MRI of the human arterial vessel wall resulted in an accurate visualization of vessel wall composition when compared to histology and, thus, allowed for a quantitative assessment. T2- and PD-weighted MRI proved capable of reliably detecting submillimeter atherosclerotic lesions. Cosima Jahnke and Thore Dietrich contributed equally to the work.     

Characterization of carotid artery plaques with USPIO-enhanced MRI: assessment of inflammation and vascularity as in vivo imaging biomarkers for plaque vulnerability

To evaluate ultra small superparamagnetic iron oxide particles (USPIO) enhanced magnetic resonance (MR) imaging for characterization of atherosclerotic carotid plaques by assessing vascularity and plaque inflammation, besides contrast-enhanced MR angiography (CE-MRA) of the carotid artery stenosis. Twelve patients with severe carotid artery stenosis, scheduled for endarterectomy, underwent MRI of the carotid artery bifurcation using SHU 555 C at a dose of 40 μmol Fe/kg BW. The MR imaging protocol comprised pre- and post-contrast T2*-w, a first-pass CE-MRA and dynamic T1-w sequences. For quantitative data analysis, the signal intensities (SI) were measured and SNR-data (SNR = SI_{blood/plaque/bone marrow}/standard deviation_noise) as well as ΔSI-data (SNR_post–SNR_pre) were calculated. In addition, two radiologists rated the diagnostic performance of first-pass MRA according to a four level decision scale. Staining of anti-dextran (SHU 555 C) and anti-CD68 (macrophages) was performed for immunohistological confirmation. Plaque sections with a T2*-w signal decline (intracellular USPIO accumulation in macrophages) showed significantly changes (mean −14%, 95% CI, −5 to −20%; P < 0.01) and corresponding plaque regions had significantly higher (15.15 ± 1.76 vs. 5.22 ± 1.50; P < 0.01) T1-w enhancement data (global estimation of vascularity). The first-pass MRA of the supra-aortal vessels provided images of diagnostic quality. Representative immunohistology sections revealed colocalization of dextran- and CD68-immunoreactive cells. USPIO-enhanced MRI is feasible for in vivo assessment of vascularity and macrophage content in atherosclerotic carotid plaques, determining an association of these potential imaging biomarkers of plaque vulnerability. Diagnostic MRA of the supra-aortal vessels can be imaged additionally with a single administration of SHU 555 C.     

大脑中动脉粥样硬化责任斑块与非责任斑块的高分辨磁共振对比研究

目的 探讨高分辨磁共振成像(HR-MRI)评估大脑中动脉(MCA)粥样硬化患者高危斑块的价值。方法 选取88例症状性MCA粥样硬化患者(症状组)和23例无症状狭窄者(无症状组),行头颅TOF磁共振血管成像(MRA)、覆盖MCA的M1段的轴位T1WI、T2WI和对比剂增强T1WI(CE-T1),以及脑DWI。定量分析狭窄率、最小管腔面积、斑块负荷以及各序列中斑块的信号强度指数。结果 症状组中,责任斑块88个,非责任斑块20个;无症状组非责任斑块23个。症状组责任病变的狭窄率和斑块负荷均明显高于无症状组非责任病变者(狭窄率:63.61%±24.13% vs 55.61%±24.83%,P=0.002;斑块负荷:86.24%±13.83% vs 75.40%±17.08%,P<0.0001);且责任病变的最小管腔面积明显低于非责任病变[(0.95±0.70)mm² vs (2.22±0.65)mm²,P<0.0001]。责任斑块与非责任斑块间斑块的T2WI和T1WI信号强度指数差异均无统计学意义(P均>0.05),但责任斑块呈混杂信号者所占比例明显高于非责任斑块(P均<0.05),症状组责任病变的CE-T1信号强度指数也明显高于无症状组非责任斑块(1.66±0.59 vs 1.37±0.62,P=0.0002)。结论 与单纯应用狭窄率对MCA动脉粥样硬化患者进行评价相比,HR-MRI的MCA管壁成像能够提供更多有价值的信息。评价MCA粥样硬化责任斑块时除了狭窄率,还应结合斑块负荷、斑块信号和强化等形态学指标进行综合考虑。     

Bilateral symmetry of human carotid artery atherosclerosis: a multi-contrast weighted MR study

The systemic nature of atherosclerotic disease may entail an association in disease severity between left and right carotid arteries. However, the etiology of plaque features in high-risk lesions is presumably attributed to local risk factors. We explored the symmetry of plaque morphology and composition across a broad range of atherosclerotic disease severities. All participants underwent carotid MR imaging on a 3.0 T scanner with a bilateral four-element phased-array surface coil. Vessel boundary and plaque components [calcification, lipid-rich necrotic core (LRNC) and intraplaque hemorrhage (IPH)] of bilateral carotid arteries were outlined. Normalized wall index (NWI) was calculated as follows: NWI?=?wall volume/total vessel volume. Carotid atherosclerosis score (CAS) was computed for plaque risk stratification. Associations of volume measurements between sides were evaluated using Pearson’s correlation. Cohen’s kappa was used to assess agreement between dichotomous variables. In the 177 participants with images of sufficient quality, there were very strong correlations between left and right lumen volumes (r?=?0.85), total vessel volumes (r?=?0.88), and strong correlations between wall volumes (r?=?0.79), mean wall thickness (r?=?0.66) and NWI (r?=?0.71), and a moderate correlation between max wall thickness (r?=?0.56) (all P?<?0.001). There were moderate between-side agreements for the presence of calcification (κ?=?0.54) and LRNC (κ?=?0.49), but only fair agreement for IPH (κ?=?0.31). The correlation of volume between left and right carotid arteries was strong for calcification (r?=?0.62, P?<?0.001) and weak for LRNC (r?=?0.39, P?<?0.001), but there was no significant correlation for IPH (r?=?0.01, P?=?0.99). Fair agreement (κ?=?0.34) for CAS between paired carotid arteries was observed. Only 16 of 47 participants with CAS?=?4 on at least one side had the same CAS on the contralateral side. Plaque morphology, calcification, and LRNC may develop symmetrically, but there is a relatively poor correlation for lipid content between sides. The weak symmetry of IPH and CAS indicates that the development of atherosclerosis into high-risk lesions may be regulated by local rather than systemic factors.     

Association of high-density lipoprotein levels and carotid atherosclerotic plaque characteristics by magnetic resonance imaging

A low level of high-density lipoprotein cholesterol (HDL-C) is a risk factor for atherosclerotic disease. Magnetic resonance imaging (MRI) can provide detailed information on carotid atherosclerotic plaque size and composition. The purpose of this study was to correlate HDL levels with carotid plaque burden and composition by MRI. Thirty-four patients with coronary artery disease (CAD) receiving simvastatin plus niacin or placebo for both drugs for three years were randomly selected to undergo MRI of carotid arteries. Atherosclerotic plaque wall volumes (WVs) and plaque components including lipid rich/necrotic core (LR/NC), calcium, fibrous tissue, and loose matrix were measured. Mean WV or atherosclerotic burden was significantly associated with total HDL-C levels (r = −0.39, P = 0.02), HDL₂ (r = −0.36, P = 0.03), HDL₃ (r = −0.34, P = 0.04), and LDL/HDL ratio (r = 0.42, P = 0.02). Plaque lipid composition or LR/NC was significantly associated with HDL₃ (r = −0.68, P = 0.02). Patients with low HDL levels (≤35 mg/dL) had increased WV (97 ± 23 vs. 81 ± 19 mm³, P = 0.05) compared with patients with HDL levels > 35 mg/dL. Among CAD patients, low HDL-C levels were significantly associated with increased carotid atherosclerotic plaque burden and lipid content by MRI.     

MRI评价兔动脉粥样硬化模型

目的 探讨1.5T MR仪检测兔颈动脉粥样硬化模型中粥样硬化斑块的形成。 方法 用动脉球囊扩张法损伤兔一侧颈总动脉血管内膜后高脂饲养15周,行MRI及损伤血管的病理学检查。 结果 15周后,MRI表现为损伤血管壁高信号区增厚并管腔狭窄,对应病理学检查显示:血管腔狭窄;损伤侧颈总动脉明显粥样斑块形成,符合动脉粥样硬化特点。MR成像与病理学所测血管壁厚度之间有相关关系(r＝0.953)。 结论 临床应用型1.5T MRI可成功检测兔颈动脉粥样硬化的形成。     

Neonate Leigh disease: Case report北大核心CSCD

目的 观察MR三维颅内血管解剖成像(3D-IVAS)技术显示大脑中动脉(MCA)的价值。方法 回顾性分析137例接受3D-IVAS及三维时间飞跃法MR血管成像(3D-TOF MRA)检查的患者,共纳入274支MCA,包括动脉粥样硬化组197支、动脉粥样硬化性烟雾综合征组23支、烟雾病组8支及正常组46支;对比3D-IVAS、3D-TOF MRA显示MCA效果评分,于3D-IVAS图像上测量各组MCA起始部血管外径,并进行比较。结果 3D-IVAS显示MCA的效果评分小于3D-TOF MRA(P<0.01)。动脉粥样硬化组、动脉粥样硬化性烟雾综合征组、烟雾病组及正常组MCA外径分别为(2.87±0.56)、(1.99±0.50)、(1.97±0.74)及(2.75±0.43)mm,组间总体差异有统计学意义(F=24.16,P<0.01),且动脉粥样硬化性烟雾综合征组、烟雾病组均小于正常组及动脉粥样硬化组(P均<0.05)。结论 利用3D-IVAS技术可清晰显示大脑中动脉外廓,有助于鉴别诊断相关疾病。     

In-vivo quantitative T2 mapping of carotid arteries in atherosclerotic patients: segmentation and T2 measurement of plaque components

Background

Atherosclerotic plaques in carotid arteries can be characterized in-vivo by multicontrast cardiovascular magnetic resonance (CMR), which has been thoroughly validated with histology. However, the non-quantitative nature of multicontrast CMR and the need for extensive post-acquisition interpretation limit the widespread clinical application of in-vivo CMR plaque characterization. Quantitative T₂ mapping is a promising alternative since it can provide absolute physical measurements of plaque components that can be standardized among different CMR systems and widely adopted in multi-centre studies. The purpose of this study was to investigate the use of in-vivo T₂ mapping for atherosclerotic plaque characterization by performing American Heart Association (AHA) plaque type classification, segmenting carotid T₂ maps and measuring in-vivo T₂ values of plaque components.

Methods

The carotid arteries of 15 atherosclerotic patients (11 males, 71 ± 10 years) were imaged at 3 T using the conventional multicontrast protocol and Multiple-Spin-Echo (Multi-SE). T₂ maps of carotid arteries were generated by mono-exponential fitting to the series of images acquired by Multi-SE using nonlinear least-squares regression. Two reviewers independently classified carotid plaque types following the CMR-modified AHA scheme, one using multicontrast CMR and the other using T₂ maps and time-of-flight (TOF) angiography. A semi-automated method based on Bayes classifiers segmented the T₂ maps of carotid arteries into 4 classes: calcification, lipid-rich necrotic core (LRNC), fibrous tissue and recent IPH. Mean ± SD of the T₂ values of voxels classified as LRNC, fibrous tissue and recent IPH were calculated.

Results

In 37 images of carotid arteries from 15 patients, AHA plaque type classified by multicontrast CMR and by T₂ maps (+ TOF) showed good agreement (76% of matching classifications and Cohen’s κ = 0.68). The T₂ maps of 14 normal arteries were used to measure T₂ of tunica intima and media (T₂ = 54 ± 13 ms). From 11865 voxels in the T₂ maps of 15 arteries with advanced atherosclerosis, 2394 voxels were classified by the segmentation algorithm as LRNC (T₂ = 37 ± 5 ms) and 7511 voxels as fibrous tissue (T₂ = 56 ± 9 ms); 192 voxels were identified as calcification and one recent IPH (236 voxels, T₂ = 107 ± 25 ms) was detected on T₂ maps and confirmed by multicontrast CMR.

Conclusions

This carotid CMR study shows the potential of in-vivo T₂ mapping for atherosclerotic plaque characterization. Agreement between AHA plaque types classified by T₂ maps (+TOF) and by conventional multicontrast CMR was good, and T₂ measured in-vivo in LRNC, fibrous tissue and recent IPH demonstrated the ability to discriminate plaque components on T₂ maps.     

磁共振定量测定儿童及青少年戈谢病肝脾脏体积及脂质含量

目的 探讨MRI定量分析儿童及青少年戈谢病患者肝脏、脾脏体积及脂质含量的价值。方法 对经骨髓穿刺证实的42例戈谢病患者（其中12例已行脾脏切除）行腹部MR检查,序列为冠状位三维梯度回波Dixon水脂分离（3D FFE mDIXON）和T2WI-STIR序列。所有患者均正在接受酶替代治疗。评估患者肝脏、脾脏脂质含量的差异及相关性。结果 42个肝脏校正的体积值为25.15~48.99 ml/kg,平均（33.66±6.03）ml/kg,脂质含量4.63%~10.09%,平均（5.90±1.10）%;30个脾脏校正的体积值为4.48~56.04 ml/kg,平均（16.36±10.65）ml/kg,脂质含量4.78%~19.39%,平均（6.63±2.62）%。同一患者脾脏脂质含量高于肝脏（t=2.16,P=0.04）。结论 采用MRI测量肝脾脏体积及脂质含量具有一定的可行性,可用于监测儿童及青少年戈谢病患者的病情及治疗效果。