肝脏磁共振扩散加权成像对肝癌化疗栓塞后疗效评价的实验性研究

目的应用MR扩散加权成像(diffusion weighted imaging,DWI)技术评价兔肝癌化疗栓塞疗效。材料与方法首先建立兔VX2肝癌模型,采用Seldinger’s法经股动脉插管行选择性肝动脉造影成功后,行肝动脉化疗栓塞术(TACE),治疗前后行MR DWI,记录表观扩散系数(apparent diffusion coefficient,ADC)值。结果 DWI图像质量随b值增加而明显下降。整个肿瘤ADC值TACE术前为(1.48±0.36)×10 s/mm2,TACE术后为(1.78±0.15)×10 s/mm2,两者差异有统计学意义(t=2.885,P<0.05)。结论 MR DWI作为无创性检查方法,可以用于评价肝癌化疗栓塞疗效。     

弥散加权成像联合普美显磁共振成像在肝癌TACE术后疗效评估中的应用

目的 探讨弥散加权成像(DWI)联合普美显(Gd-EOB-DTPA)MR成像在肝癌TACE后疗效评估中的应用价值.方法 20例确诊肝癌患者于TACE术前、术后行上腹部DWI及Gd-EOB-DTPA动态增强扫描,定性分析TACE术前、术后肝癌活性成分,坏死和复发转移情况.测量TACE术前、术后病灶的表观弥散系数(ADC)值和信号值(signal intensity,SI),并计算术前、术后病灶的动脉期对比增强比(CER)和动脉期的信号比(SIR),对定量参数ADC、CER和SIR值进行配对样本t检验.结果 本组20例患者共检出肝癌病灶45个.TACE术后瘤灶内残存及复发部分在DWI图像上呈高信号,ADC图上信号低于正常肝组织,动脉期可见明显强化,门脉期及平衡期强化减退,肝胆特异期呈明显低信号;瘤灶内坏死部分DWI序列呈低信号,ADC图上为高信号,增强扫描后无强化,肝胆特异期亦呈明显低信号.肝癌病灶术前、术后ADC值分别为(1.52±0.16)×10-3 mm2/s和(1.70±0.28)×10-3 mm2/s,术后肝癌病灶的ADC值普遍升高,两者的差异有统计学意义.肝癌TACE术后的CER动脉期和SIR动脉期值减小,与术前相比,两者的差异有统计学意义.有效组肝癌病灶的术后ADC值大于无效组,而其CER动脉期和SIR动脉期值均小于无效组,两者术后的ADC、CER动脉期和SIR动脉期值的差异均有统计学意义.结论 联合应用DWI和Gd-EOB-DTPA增强MR成像能有效评估肝癌TACE术后病灶存活及坏死情况,检出早期复发、新发灶及转移灶,对制定下一步治疗方案具有重要意义.     

前列腺癌的MR扩散成像初步研究

目的初步评价MR扩散成像(DWI)对前列腺癌的诊断可行性。方法28例前列腺癌患者及20例前列腺正常的对照组受试者行MR DWI检查,使用回波平面扩散张量成像序列,b值为1000s/mm2。测量正常前列腺外周带及前列腺癌区域的表观扩散系数(ADC)值。同时测量每位受检者膀胱区域的ADC值。结果48例中44例(91.7%)获得前列腺外周带和膀胱的ADC值。24例前列腺癌灶的ADC值为(0.35±0.06)×10-3mm2/s,20例正常前列腺外周带的ADC值为(1·35±0.30)×10-3mm2/s,前列腺癌灶较正常前列腺外周带ADC值低(t=11.99,P=0.00)。前列腺癌患者膀胱的ADC值为(1.27±0.21)×10-3mm2/s,对照组膀胱ADC值为(1.29±0.30)×10-3mm2/s,2组之间差异无统计学意义(t=1.15,P=0.48)。结论MR DWI可用于前列腺的检查。前列腺癌灶与正常前列腺外周带ADC值的差别有可能用于前列腺癌的鉴别诊断。     

颅内表皮样囊肿ADC值的测量

目的分析颅内表皮样囊肿(ECs)的DWI特征,评价“T2shine-through”效应。方法手术病理证实15例ECs,其中3例术后复查残留。测量ECs、深部脑白质、脑脊液(CSF)的表观弥散系数(ADC)值;比较DWI与FLAIR对病灶的显示。结果(1)15例病灶DWI均呈高信号,ADC值(0.80~1.23)×10-3mm2/s,平均(1.05±0.14)×10-3mm2/s;深部脑白质ADC值(0.74~1.09)×10-3mm2/s,平均(0.88±0.09)×10-3mm2/s;CSF的ADC值(2.98~3.78)×10-3mm2/s,平均(3.31±0.21)×10-3mm2/s;ECs的ADC值低于CSF(P<0.001),高于脑白质(P=0.005),与脑灰质近似。(2)15例病人中,在FLAIR上6例病灶轮廓清楚,DWI上12例病灶轮廓清楚,对病灶轮廓勾画存在显著性差异,P=0.025(χ2值5.00)。(3)5例复查病人中,2例DWI上没有显示高信号病灶,3例病变区小的高信号病灶。结论颅内表皮样囊肿ADC值降低不明显,与DWI高信号不匹配,是由于增强T2效应。DWI能最好的显示病灶,对小病灶检测、术后评估优于其它成像序列。     

MR扩散加权成像诊断膝关节骨关节病髌骨软骨病变的价值

目的探讨 MR 扩散加权成像(DWI)在膝关节软骨早期病变诊断中的临床应用价值。方法 18例正常健康志愿者36个膝关节、10例骨关节炎(OA)患者18个膝关节行常规序列及 DWI序列扫描。测量髌软骨各个感兴趣区的表观扩散系数(ADC)值,比较各组间的差异。结果正常健康志愿者组36个髌软骨 ADC 均值(ADCav)为(7.8±2.3)×10~(-4)mm~2/s,髌软骨上、中、下部的 ADC值分别为(7.9±2.3)×10~(-4)mm~2/s、(7.7±2.7)×10~(-4)mm~2/s、(7.9±2.5)×10~(-4)mm~2/s,之间差异无统计学意义(F=0.050,P=0.951)。OA 患者髌软骨 ADCav 为(10.5±4.1)×10~(-4)mm~2/s,髌软骨上、中、下部的 ADC 值分别为(10.8±4.1)×10~(-4)mm~2/s、(10.4±4.4)×10~(-4)mm~2/s、(10.5±4.2)×10~(-4)mm~2/s,之间差异无统计学意义(F=0.940,P=0.910)。但 OA 组的 ADC 值明显高于正常组,两组间差异有统计学意义(t=-2.577,P=0.017),其中以髌软骨内侧份 ADC 值改变最为显著。结论MR DWI 能发现常规 MR 软骨信号尚未改变的更早期软骨病变。     

大鼠C6胶质瘤的MR扩散加权成像及病理对照研究

目的观察大鼠脑C6胶质瘤模型的MR扩散加权成像(DWI)表现,并与肿瘤细胞密度等病理学变化进行对照,分析胶质瘤DWI表现的病理学基础。方法肿瘤细胞接种后12～18d分别对16只肿瘤生长良好的大鼠C6胶质瘤模型进行MR增强及DWI检查,观察胶质瘤MR增强及DWI表现,并与病理学改变进行对照分析。结果7例肿瘤灶增强MRI呈环行强化,表观扩散系数(ADC)图均显示肿瘤中心区域信号明显升高,肿瘤中心与周围区域ADC值分别为[(106.5±11.9)×10-5]、[(78.2±9.2)×10-5]mm2/s,两者之间差异有统计学意义(t=8.26,P<0.01);病理学显示该7只肿瘤灶内部明显坏死,细胞密度明显下降,肿瘤中心及周围区域细胞密度分别为(13±8)%、(40±5)%,两者间差异有统计学意义(t=6.55,P<0.01)。另外9只MR增强扫描肿瘤强化均匀,但其中6只ADC图信号不均匀,中心区及周围区ADC值分别为[(94.1±12.6)×10-5]、[(75.8±11.4)×10-5]mm2/s,两者之间差异有统计学意义(t=5.38,P<0.05)。镜下观察肿瘤中心区域细胞密度下降,肿瘤中心区域及周围区域肿瘤细胞密度分别为(29±4)%、(41±8)%,两者之间差异有统计学意义(t=3.92,P<0.05)。3只ADC图显示信号均匀的肿瘤灶中,其中心区及周围区ADC值分别为[(86.7±9.0)×10-5]、[(84.2±7.6)×10-5]mm2/s,两者之间差异无统计学意义(t=3.41,P>0.05)。镜下肿瘤中心及周围细胞密度分别为(38±7)%、(40±5)%,两者间差异无统计学意义(t=1.92,P>0.05)。结论DWI及ADC的信号差异可以反映胶质瘤内部细胞密度的差异,区别肿瘤内部坏死后的细胞稀疏区和肿瘤增殖旺盛的细胞密集区,为从微观角度观察胶质瘤的结构变化提供了基础。     

ADC值在髓母细胞瘤瘤周浸润及复发评估中的价值

【摘要】目的：探讨ADC值在髓母细胞瘤（MB）瘤周浸润及复发评估中的价值。方法：将具有手术病理证实、术前常规MRI平扫、增强和DWI检查,且术后至少2次MRI随访的29例MB患者,根据术后随访结果分为复发组与未复发组,将两组患者的肿瘤实质区、瘤周区最小ADC值,瘤周相对ADC值（瘤周区与对侧正常脑组织区最小ADC值的比值,即rADC）进行统计学分析,同时绘制ROC曲线,评估ADC值预测肿瘤浸润及复发的诊断效能。结果：29例MB患者中,复发组15例,未复发组 14例。复发组的瘤周区最小ADC值［（0.558±0.053）×10-3mm2/s］小于未复发组［（0.637±0.043）×10-3mm2/s］,两者差异具有统计学意义（Z=3.295,P<0.05）;复发组的rADC值（0.853±0.065）小于未复发组（0.933±0.073）,两者差异具有统计学意义（Z=2.581,P<0.05）;瘤周区最小ADC值取0.606×10-3mm2/s时,预测MB瘤周细胞浸润的诊断敏感度为78.6%,特异性为73.3%。结论：ADC值对预测MB瘤周浸润及复发有辅助诊断价值。     

ADC直方图在椎体压缩性骨折时间判定中的应用

【摘要】目的：探讨表观扩散系数（ADC）直方图在椎体压缩性骨折时间判断中的可行性。方法：搜集42例胸腰椎压缩性骨折病例,在30d和90d时行磁共振扩散加权成像（DWI）,在AW4.6上后处理得到ADC图,计算基于感兴趣区（ROI）的平均ADC值,对骨折整体进行ADC直方图分析,计算ADC值直方图的平均值、中位数、标准差、峰度值和偏度值。采用t检验比较30d和90d时的各参数之间是否存在差异,并利用受试者特性曲线（ROC曲线）评价存在统计差异的参数诊断效能。结果:骨折30d时,基于ROI的ADC平均值,直方图ADC平均值以及中位数分别为(1.14±0.34)×10-3mm2/s、(1.22±0.38)×10-3mm2/s及(0.97±0.26)×10-3mm2/s,而骨折90d时,上述参数分别为(0.81±0.44)×10-3mm2/s、(0.75±0.42)×10-3mm2/s及(0.72±0.34)×10-3mm2/s。90d时的上述参数均低于30d时的参数,有显著统计学差异（P<0.05）,其ADC值分别为0.811、0.902和0.870。结论:直方图ADC平均值能鉴别新鲜骨折及陈旧骨折,为临床确定骨折时间提供了一定的依据。     

磁共振弥散加权成像观察胰腺癌冷冻术后近期疗效的应用价值

目的 探讨采用磁共振弥散加权成像(MRI-DWI)评估胰腺癌冷冻术后肿瘤坏死及肿瘤残存的应用价值.方法 对接受冷冻治疗的26例胰腺癌患者行T1WI、T2WI常规MRI平扫、DWI序列及动态增强扫描.观察胰腺癌冷冻前后MRI信号改变.测量并比较正常胰腺、术前肿瘤组织及术后残存、坏死组织的表现弥散系数(ADC)值.评价肿瘤组织ADC值与肿瘤大小的相关性,不同肿瘤直径、肿瘤位置及分期表现ADC值的差异.结果 26例患者中16例肿瘤完全坏死,冷冻坏死的胰腺肿瘤组织在T1WI图像上呈低信号,T2WI呈高信号,DWI呈低信号,动态增强无强化.活性肿瘤组织残留9例(其中7例肿瘤直径＞5.0 cm),残留率为34.6％.ADC值由低到高依次为:术前胰腺肿瘤组织(1.022±0.126)×10-3 mm2/s、术后残存肿瘤组织(1.130±0.155)×10-3 mm2/s、正常胰腺组织(1.924±0.124)×10-3 mm2/s及术后坏死组织(2.312±0.214)×10-3 mm2/s.术前胰腺肿瘤组织ADC值与术后残存肿瘤组织相比,差异无统计学意义(P=0.452),与正常胰腺组织、术后坏死组织相比,差异有显著统计学意义(P＜0.001).胰腺肿瘤ADC值与肿瘤大小呈负相关(R=-0.43,P=0.027 2),与肿瘤位置、肿瘤分期无关(P=0.738 8,P=0.089 5).结论 DWI能有效鉴别胰腺癌冷冻治疗后的病灶坏死及残存,为进一步临床诊治提供依据.     

DWI对直肠黏液腺癌与非黏液腺癌的鉴别诊断价值

目的:探讨磁共振扩散加权成像(DWI)及其表现扩散系数(ADC)值对直肠黏液腺癌与非黏液腺癌的鉴别诊断价值.方法:回顾性分析经手术病理证实的16例直肠黏液腺癌与64例非黏液腺癌患者的MR资料,观察所有肿瘤的DWI信号强度,测量肿瘤ADC值及相对ADC(rADC)值,并绘制受试者工作特性(ROC)曲线,计算ADC值及rADC值对直肠黏液腺癌与非黏液腺癌的鉴别诊断效能.结果:16例直肠黏液腺癌中4例在DWI图像上呈低号,12例呈高信号,64例非黏液腺癌中1例呈低信号,63例呈高信号,两者DWI信号强度差异有统计学意义(x2=8.333,P=0.004).黏液腺癌的ADC值[(1.48±0.25)×10 3 mm2/s]及rADC值(1.22±0.18)均高于非黏液腺癌[(1.08±0.11)×101 mm2/s,(0.95±0.11)],差异均具有统计学意义(t=6.162,P＜0.001;t=5.810,P＜0.001).以ADC值=1.209×10 3mm2/s鉴别诊断黏液腺癌与非黏液腺癌的效能最高(AUC 0.923,敏感度93.8％,特异度89.1％).结论:DWI及ADC值在直肠黏液腺癌与非黏液腺癌的鉴别诊断中具有重要价值.     

Guest Lecture (GL) Honorary Lectures (HL) Categorical Courses (CC) Refresher Courses (RC) Workshops (WS) State-of-the-Art Symposia (SA) Special Focus Sessions (SF)

European Radiology -     

(3)He-particle-induced reactions on (nat)Sb for production of (124)I.

Excitation functions of the reactions (nat)Sb((3)He,xn)(124,123,121)I were measured from their respective thresholds up to 35 MeV, with particular emphasis on data for the production of the medically important radionuclide (124)I. The conventional stacked-foil technique was used. From the experimental data the theoretical yields of the three investigated radionuclides were calculated. The yield of (124)I over the energy range E9(30He) = 35 --> 13 MeV amounts to 0.95 MBq/microA h. The radionuclidic impurities are discussed. A comparison of (3)He- and alpha-particle-induced reactions on antimony for production of (124)I is given. The alpha-particle-induced reaction on enriched (121)Sb and the (3)He-particle-induced reaction on enriched (123)Sb would lead to comparable (124)I yields, but the level of impurities in the latter case would be somewhat higher.     

家族性多发性神经纤维瘤病(附5例报告)

本文报道了家族性神经纤维瘤病5例,着重讨论了本病较少见的胸部X线改变,主要表现为:(1)胸廓畸形及部分肋骨纤细扭曲;(2)肺间质纤维变;(3)纵膈神经源性肿瘤;(4)心脏改变。并述及其它部分骨的异常X线改变和有关的鉴别诊断。     

Excitation functions of (alpha,xn) reactions on (nat)Rb and (nat)Sr from threshold up to 26 MeV: possibility of production of (87)Y, (88)Y and (89)Zr.

Excitation functions were measured by the stacked-foil technique for (nat)Rb(alpha,xn)(87m,87m+g,88)Y and (nat)Sr(alpha,xn)(86,88,89)Zr reactions from their respective thresholds up to 26 MeV. The samples for irradiation were prepared by sedimentation and pellet pressing techniques. The measured data were compared with those available in the literature. From the excitation functions, integral yields of the products were calculated. The suitable energy ranges for the production of (87)Y and (88)Y via (nat)Rb(alpha,xn) processes and of (89)Zr via the (nat)Sr(alpha,xn) process are E(alpha)=26-->20 MeV, E(alpha)=26-->5 MeV and E(alpha)=20-->8.5 MeV, respectively. The respective yields amount to 8.2, 0.08 and 0.9 MBq/microA h. Production of (88)Y is feasible if a waiting time of about 2 months is allowed to let the impurities decay out. Also, (87)Y can be produced with a relatively low impurity of (88)Y. The yields of both (88)Y and (87)Y via the present routes are, however, appreciably lower than those via the (nat)Sr(p,xn) processes. There is a possibility to produce (89)Zr via the alpha-particle irradiation of (nat)Sr. The yield is rather low but would be considerably increased if enriched (86)Sr would be used as target material. The radionuclidic impurity levels in all the three products are discussed.     

PEG coating reduces NMR relaxivity of Mn(0.5)Zn(0.5)Gd(0.02)Fe(1.98)O4 hyperthermia nanoparticles

Purpose:

To investigate both T1 and T2 MR relaxation enhancement of Gd substituted Zn‐Mn ferrite magnetic nanoparticles. Both uncoated and polyethylene glycol (PEG) coated particles were used.

Materials and Methods:

Chemical co‐precipitation was used to synthesize particles in the form Mn_0.5Zn_0.5Gd_0.2Fe_1.98O₄ suitable for hyperthermia applications. Physical characterization of the magnetic nanoparticles included SEM, TEM, ICP, and SQUID. T1 and T2 measurements were performed at 1.5 Tesla (T).

Results:

The saturation magnetization was 12.86 emu/g while the particle's magnetic moment was 1.86 × 10^?19 J/T. The particle size increased due to coating, while 1/T1 and 1/T2 relaxivities (26°C) decreased from 2.5 to 0.7 and from 201.3 to 76.6 s^?1 mM^?1, respectively, at a magnetic field 1.5T.

Conclusion:

The reduction in both 1/T1 and 1/T2 is attributed to increased distance of closest approach between the protons and the magnetic core caused by the shielding provided by the high molecular weight PEG. 1/T2 data are compared with existing theoretical models using a modified radius that takes into account both possible agglomeration of the particles and increased inter‐particle separation induced by PEG coating. J. Magn. Reson. Imaging 2011;. © 2011 Wiley Periodicals, Inc.

     

Uptake of hexakis(t-butylisonitrile) technetium (I) and hexakis(isopropylisonitrile) technetium (I) by neonatal rat myocytes and human erythrocytes

The uptake mechanism of two potential cardiac imaging agents [99mTc]hexakis(t-butylisonitrile) technetium (I) (TBI) and [99mTc]hexakis(isopropylisonitrile) technetium (I) (IPI) has been studied using neonatal rat myocytes and human erythrocytes. Uptake of these complexes was rapid, of greater magnitude than seen previously for 42K, and was unaffected by either 0.15 mM ouabain or 10 mM KCI. Both [99mTc]isonitrile complexes had a high affinity for the membranes of the myocytes and erythrocytes. The data suggest that the uptake is not dependent on the membrane Na+/K+ ATPase but may be related to the lipophilicity of these agents as evidenced by the rapidity, tenacity, and quantity of the binding observed.