磁共振弥散加权成像评价肝纤维化的临床病理对照研究

Objective To evaluate the clinical practical value of apparent diffusion coefficient (ADC) measurements based on diffusion-weighted MR imaging (DWI) for quantification of liver fibrosis and inflammation for hepatitis viral infection.Methods Diffusion-weighted MRI with parallel imaging was prospectively performed on 85 patients with chronic hepatitis and on 22 healthy volunteers within a single breath-hold using a single-shot spin-echo echo-planar sequence at b values of 100, 300, 500,800 and 1000 s/mm2 respectively. ADC values of liver were measured with five different b values. The inflammation grades and fibrosis stages were evaluated histologically by biopsy. One-way analysis of variance and Spearman' s rank correlation test were used for statistical analysis. Receiver operating characteristics analysis was used to assess the performance of ADC in predicting the presence of stage ≥2 and stage ≥3 hepatic fibrosis, and grade ≥1 hepatic inflammation. Results There was moderate negative correlation between hepatic ADC values and fibrosis stage. And the best correlation was obtained for a b value of 800 s/mm2 (r = - 0. 697, P=0.000). At all b values there was a significant decrease in hepatic ADC in patients with stage ≤1versus stage ≥2 fibrosis and stage ≤2 versus stage ≥3 fibrosis (P <0. 05). Hepatic ADC was a significant predictor of stage ≥2 and ≥3 fibrosis. The areas under the curve were 0. 909 vs 0. 917, sensitivity 76. 6% vs 80. 0% and specificity 88. 3% vs 91.5% (ADC with a b value of 800 s/mm2, 1.26 × 10<'3> mm2/s or less and 1.19 × 10-3 mm2/s or less). There was weak to moderate negative correlation between ADCs and inflammation grade. Hepatic ADC was a significant predictor of grade ≥1 inflammation with an area under the curve of 0. 781, sensitivity of 60. 0% and specificity of 86. 4% (ADC with a b value of 500 s/mm2, 1.54 × 10-3 mm2/s or less). Conclusion The D WI measurement of hepatic ADC can be used to quantify liver fibrosis and inflammation. It will be a new approach for early diagnosis and therapeutic follow-up of hepatic fibrosis.     

肝局灶性结节增生的MRI表现

目的 对肝局灶性结节增生(FNH)的MRI表现进行分析和总结，以提高对FNH MRI表现的认识。资料与方法 经手术病理证实的FNH18例，24个病灶，均作快速多层面扰相梯度回波(FMPSPGR)动态增强，11例作SET1WI、PDWI及T2WI，7例作SET1WI及FSET2WI。结果 24个病灶中，2个有典型中心瘢痕，9个有不典型中心瘢痕；动脉期明显强化23个；门脉期7个明显强化，15个中度强化，中心线样或点状强化6个；平衡期16个病灶中度强化，8个轻度强化，中心线样或点状强化2个；延迟期17个病灶，12个轻度强化，5个与肝实质等信号，4个有中心线样或点状强化。结论 MRI可对多数FNH(83．3％)作出正确诊断，对不典型FNH应结合病史及SPIO或Gd-EOB-DTPA动态扫描综合判断。     

Mn-DPDP增强MRI胰腺强化特征以及与Gd-DTPA动态增强MRI比较的初步研究

目的　探讨Mn DPDP增强MRI胰腺强化特征 ,并与Gd DTPA动态增强比较 ,为Mn DPDP增强胰腺MRI的临床应用提供指导。资料与方法　 46例患者因肝脏局灶病变行Gd DTPA动态增强和Mn DPDP增强MRI,其中 2 9例图像及临床病史无胰腺病变者入选本研究。常规平扫及Gd DTPA动态增强 ;次日经肘静脉缓慢滴注Mn DPDP(0 .5ml/kg体重 ) ,于给药结束后 5～ 40min内每 5min以及 2 4h行SET1W及SPGRT1W扫描。结果　正常胰腺于注药结束后 5min即强化 (SNR高于平扫 ,P <0 .0 5 ) ,5～ 40min维持于一平台期 ,胰腺信号强度于 35min达到最大 ,SET1W及SPGRT1W图像上强化指数 (CEI)分别为 74%± 36和 80 %± 2 9(两者间差别无统计学意义 ,P >0 .0 5 ) ;2 4h胰腺SNR仍较平扫高 (P <0 .0 5 )。给药结束后 35minSPGRT1W图像上胰腺CEI(80 %± 2 9)低于Gd DTPA动态增强动脉期 (10 8%± 2 6 ) (P <0 .0 5 ) ,与门脉期的 85 %± 2 5相似 (P >0 .0 5 ) ,比延迟期的 6 9%± 13高 (P <0 .0 5 )。结论　正常胰腺Mn DPDP增强扫描显著强化 ,能达到Gd DTPA动态增强门脉期胰腺强化程度 ,并能提供充裕的扫描时间窗及可采用除SPGRT1W序列外SET1W序列扫描。     

超顺磁性氧化铁在肝脏局灶性病变中的定性研究

目的 探讨超顺磁性氧化铁（SPIO）增强MRI在肝脏局灶性病变的定性能力。材料与方法 43例怀疑肝占位者经常规MRI和Gd-DTPA增强后1－7后,行SPIO增强检查。其中31例经手术病理证实,12例经随访、实验室生化检查及临床资料证实。分析平扫MRI及SPIO增强后病灶的信号变化,并与Gd-DTPA动态增强结果相对照。结果 43例共12种病变、单发病灶21例,多病灶22例。包括原发性肝细胞肝癌22例,血管瘤5例,囊肿4例,转移性肝癌5例,肝硬化结节4例,局灶性结节增生（FNH）5例,其他病变6例。22例多发病灶中有8例合并1或2种病变。SPIO增强后,肝细胞肝癌T1WI为等或略高信号,T2WI为较高信号;血管瘤T1WI为较高信号,T2WI信号同平扫为高信号;囊肿T1WI、T2WI信号无改变;肝硬化结节T2WI为等信号同正常肝实质;FNH T2WI信号明显下降。其余病变的诊断SPIO增强不具有特征性,须与Gd-DTPA动态增强相结合。结论 SPIO具有一定的定性能力Gd-DTPA增强相结合,可帮助提高肝局灶性病变诊断和鉴别诊断的准确性。     

心肌梗死延迟增强三维与二维MR成像对比研究

Objective To prospectively evaluate the correlation between a single breath-hold three-dimensional (3 D) and several breath-hold two-dimensional (2D) delayed enhancement MR imaging sequences in the assessment of myocardial infarction size and the differences on image quality. Methods Fifteen patients with myocardial infarction underwent MR scan by using a single breath-hold 3D inversion-recovery fast low-angle shot (FLASH) sequence and several breath-hold 2D turbo-FLASH as the reference standard. Paired-samples t test was used to compare the ratio of the infarction areas in two sequences. Two-way ANOVA was used to assess the contrast-to-noise ratio (CNR) on 3D,2D magnitude-reconstructed and 2D phase-sensitive (PS) images. P value less than 0.05 was considered to indicate a significant difference. Meanwhile subjective visual evaluation was also performed to compare the image quality. Results The infarction ratio determined by 3D MR imaging 31.28% was no significant difference with that of 2D MR imaging 30.91% and had a good correlation (t = -0.505,P =0.621,r =0.990). The CNR was significantly higher in 3D and 2D magnitude-reconstructed groups than in 2D-PS group (3D and 2D magnitude-reconstructed images, 2D P5 image, 43.43±20.67 and 34.10±14.29, 7.59±2.59, respectively) (F = 24.376, P < 0.01). However, the contrast between normal and infracted myocardium was the highest in 2D-PS group with subjective visual evaluation (scores of 3D, 2D magnitude-reconstructed and 2D-PS images, 2.33, 2.13 and 2.73, respectively). On the other hand, the background noise on 2D-PS images was the highest in 3 groups (scores of 3 D, 2 D magnitude-reconstructed and 2 D-PS images, 2.67, 2.53 and 1.20, respectively). Conclusion The myocardial infarction ratio obtained with 3D MR imaging sequence is accurate, and the image quality is good.     

磁共振灌注成像参数图在小乳腺癌诊断中的初步应用

目的:研究小乳腺癌在各种MR灌注参数图像上的影像表现及其灌注特征,评价磁共振灌注成像参数图的临床应用价值.方法:29例女性小乳腺癌[共46个经病理证实的病灶(最大径≤2cm)]被纳入研究范畴.采用快速小角度激发(FLASH)序列行双侧乳腺动态高分辨对比增强MR成像(DCE MRI),共连续6个回合成像,绘制时间一信号强度曲线(TIC),并选取3个时间点,通过软件获得Washin、Washout、MIPt及PEI等4种乳腺灌注伪彩参数图像,分别测定整个病灶、病灶周边及中心以及对侧正常乳腺组织的各灌注参数值,分析小乳腺癌的灌注特点.结果:Washin、Washout、MIPt及PEI等4种灌注参数图像分别可以显示41个、19个、44个及45个小乳腺癌灶,检出率分别为89.1%、41.3%、95.7%及97.8%.Washin图不能检出的5个病灶中4个(80.0%)TIC为Ⅰ型曲线,Washout图检出的19个病灶中,15个(78.9%)为Ⅲ型曲线.46个小乳腺癌中,35个(76.1%)呈现明显不均匀异常灌注增强,其中26个周边灌注更明显.对各参数值的测定及分析结果显示小乳腺癌灶与正常乳腺组织之间、乳癌周边部分与中心部分间的各灌注参数值差异有统计学意义(P<0.05).结论:乳腺动态高分辨对比增强MR灌注成像参数图对乳腺癌病灶的检出率较高,大部分小乳腺癌呈明显不均匀灌注增强,且增强早期即出现异常灌注,周边部分灌注更显著.乳腺MR灌注参数图像可为小乳腺癌的诊断和鉴别提供重要的补充信息.     

肝门胆管癌的磁共振诊断

评价磁共振成像在肝门胆管癌检查中的用途肝门胆管癌的ＭＲＩ表现与组织病理学的关系。材料与方法搜集２４例经手术和病理证实的肝门胆管癌,分析肿瘤在ＭＲＩ上的表现,包括肿瘤生长类型,自旋回波（ＳＥ）Ｔ１和Ｔ２ＷＩ上的信号特点以及动态增强规律,评价用ＭＲＩ判断肿瘤累及范围的准确性,研究肿瘤的组织病理学特点。     

5.0T MR磁敏感加权成像显示脑小静脉及检测脑微出血

目的 观察5.0T MR磁敏感加权成像(SWI)显示脑小静脉及检测脑微出血(CMB)的价值。方法 前瞻性对30例疑因脑小血管病致脑卒中患者行3.0T及5.0T头颅MR检查,对比不同场强下SWI图像质量、显示脑小静脉及检出CMB效果。结果 5.0T SWI图像质量评分、信噪比、对比度噪声比、显示脑深部静脉及皮层下静脉评分、检测CMB数量及脑皮质表面铁沉积检出率均高于3.0T SWI(P均＜0.05)。3.0T及5.0T SWI评估CMB位置一致性极好(Kappa=1.0)。结论 5.0T SWI显示脑小静脉及检测CMB效果均优于3.0T SWI,可用于评估脑小血管病所致脑卒中。     

单次屏气及自由呼吸TSENSE技术对心功能测量及图像质量的评价

目的:评价TSENSE技术在不同加速因子及自由呼吸状态下测量心功能的准确性及图像质量.方法:15例患者真实稳态自由进动(trueFISP)全心短轴位电影检查.检查序列包括多次屏气trueFISP结合GRAPPA,不同加速因子(2～4)单次屏气TSENSE和自由呼吸TSENSE(R=3).测量并比较各种序列所测心脏射血分数(EF)、舒张末期容积(EDV)和收缩末期容积(ESV).结合乳头肌水平图像的对比噪声比(CNR)对各序列图像质量进行评价.结果:与GRAPPA相比,TSENSE各序列所测心功能指标差异无显著性意义(P＞0.05),两者结果具有一致性.各序列图像均具有诊断性,以GRAPPA和R=2时TSENSE图像质量最佳.结论:单次屏气和自由呼吸TSENSE技术全心扫描能准确评价左心室容积大小,以R=3时TSENSE序列最适合临床运用.     

不同程度肝纤维化背景下小肝癌的磁共振表现比较分析

目的 比较不同程度肝纤维化背景下小肝细胞癌(sHCC)(≤2 cm)的MRI表现.方法 回顾性分析经手术病理证实的216例sHCC患者234个病灶,根据镜下纤维化程度的不同,将患者分为三组:1组,轻度纤维化(F0-1);2组,中重度纤维化(F2-3);3组,肝硬化(F4).对三组病灶的形态学特征及MR信号特征进行定性定量分析.结果 分别有14、35及167名患者纳入1、2、3组.1组较2、3组患者年长(H=8.834,P=0.0121).三组病灶在T2 WI信号(P =0.383)、强化模式(P =0.559)、增强后三期信号特点(P =0.690,0.811,0.124)、(假)包膜征象(P=0.812)及表观扩散系数(ADC) (P =0.567)等方面均无统计学差异.定量分析结果显示,动态增强扫描中三组病灶间信噪比(x2 =2.119,P=0.122)及对比噪声比(x2=1.533,P=0.218)总体上不存在组间差异.T2WI等低信号、动脉期相对低信号及进展强化模式等不典型表现仅见于2、3组患者中.结论 不同程度肝纤维化背景下sHCC的MRI表现不存在显著差异.