早期糖尿病肾病大鼠模型磁共振弥散加权成像的初步研究

目的:探讨早期糖尿病肾病(Diabetic nephropathy,DN)模型大鼠磁共振弥散加权成像(Diffusion Weight Imaging,DWI)肾实质ADC值变化规律。方法:将20只清洁级雄性SD大鼠随机分成两组,糖尿病肾病组(DN组)12只,正常对照组(NC组)8只;DN组给予60 mg/kg链尿佐菌素腹腔注射诱导糖尿病肾病模型,NC组按照相同方法、相同剂量柠檬酸缓冲液腹腔注射;并对最终糖尿病模型造模成功并且存活的8只DN大鼠、8只NC大鼠进行MRI扫描,包括常规轴位T1WI、T2WI扫描及DWI扫描;扫描结束后收集血液送血肌酐及双肾组织进行病理检查。并测量每只大鼠双肾皮、髓质的ADC值。结果:造模后,DN组大鼠血糖明显升高、尿量明显增加、体重明显减低,DN组大鼠肾脏出现不同程度病理损伤,符合早期DN病理改变。DN组大鼠肾脏皮、髓质ADC值分别为1.522±0.913×10^-3 mm^2/s、1.268±0.388×10^-3 mm^2/s,较NC组肾脏皮、髓质ADC值1.276±0.341×10^-3 mm^2/s、1.011±0.217×10^-3 mm^2/s增高,两组比较有统计学意义(P<0.05)。结论:DWI成像ADC值可能反映早期糖尿病肾病肾脏功能的变化。     

磁共振全身扩散加权成像在不同类型淋巴瘤中的应用价值研究

目的:探讨磁共振全身扩散加权成像(WB-DWI)在不同病理类型淋巴瘤的筛查、诊断及治疗中的应用价值。方法:选择2015年1月~2017年6月经我院病理证实的淋巴瘤患者60例作为淋巴瘤组,另选择同期健康志愿者43例作为对照组,所有对象均进行磁共振WB-DWI检查(淋巴瘤组于治疗前和治疗后检查),测量其淋巴结表观扩散系数(ADC)值,比较淋巴瘤组与对照组、淋巴瘤组不同部位、不同病理类型及治疗前后不同疗效淋巴瘤患者的淋巴结ADC值差异。结果:淋巴瘤组平均ADC值为(755.37±48.42)×10-6 mm~2/s,低于对照组的(1185.92±66.53)×10-6 mm~2/s,差异有统计学意义(P0.05);不同部位、不同病理类型(包括不同细胞来源)淋巴瘤患者的ADC值比较,差异无统计学意义(P0.05);不同疗效淋巴瘤患者的ADC值治疗前与治疗后比较,差异有统计学意义(P0.05);治疗前、治疗后不同疗效淋巴瘤患者的ADC值比较,差异有统计学意义(P0.05)。结论:淋巴瘤患者WB-DWI的ADC值较健康者显著降低,而且不同疗效的淋巴瘤患者具有不同的ADC值,因此,WB-DWI检查可作为淋巴瘤的筛查、诊断及疗效评估的方法。     

磁共振体素内不相干运动扩散加权成像在肺癌所致肺不张影像诊断中的初步应用

目的:探讨磁共振体素内不相干运动扩散加权成像(intravoxel incoherent motion diffusion weighted MR Imaging,IVIM-DWI)在肺癌所致肺不张的影像诊断中的初步应用。方法:选取独立肺段肺不张病变患者43例,其中肺癌致肺不张31例(肺癌组),局部炎症致肺不张12例(炎症组)。所有患者在药物治疗或手术前均行3.0T磁共振IVIM-DWI检查,b值取0、50、100、200、400、600、800、1000 s/mm~2,分别测量灌注分数(perfusion fraction,f)、真实扩散系数(diffusion coefficient,D)以及关注相关扩散系数(diffusion coefficient from the perfused compartment,D*),对上述参数值进行相关统计学分析,并依据受试者工作特征曲线(Receiver Operating Characteristic,ROC)对各参数的评价效能进行分析。结果:肺癌组的D值、D*值以及f值分别为(0.64±0.16)×10~(-3)mm~2/s、(19.77±6.16)×10~(-3)mm~2/s以及(29.62±9.74)%,而炎症组的D值、D*值以及f值分别为(0.67±0.14)×10~(-3) mm~2/s、(21.14±8.32)×10~(-3)mm~2/s以及(47.62±11.46)%;经比较,肺癌组D值、D*值与炎症组无统计学差异(P0.05),而二者f值差异显著,有统计学意义(P0.01)。f值最佳阈值为38.42%,此时曲线下面积(Area Under Curve,AUC)为0.94,诊断肺癌的特异度为0.89,敏感度为0.93,阳性预测值为0.92,阴性预测值为0.89。结论:磁共振IVIM-DWI技术在肺癌所致肺不张的影像诊断中具有一定的应用价值。     

磁共振弥散加权成像在兔良恶性淋巴结鉴别中的价值

目的:采用动物模型研究MR弥散加权成像评价转移性淋巴结与反应增生性淋巴结的价值。方法:24只新西兰兔随机分成两组,分别制作转移性淋巴结与反应增生性淋巴结模型,比较两组淋巴结的表观弥散系数(ADC),同时在DWI图上测量并比较两组淋巴结与肌肉的相对信号强度,并进行病理结果分析。结果:两组淋巴结的DWI相对信号强度无显著性差异(P>0.05)。转移性淋巴结组ADC值大于反应性增生组ADC值,分别为0.82±0.10×10-3mm2/s和1.17±0.14×10-3mm2/s,差异有统计学意义(P<0.05)。结论:MR弥散加权成像ADC值测量有助于转移性淋巴结与反应增生性淋巴结的鉴别     

MRI多b值DWI序列在孤立性肺结节良恶性鉴别诊断中的价值

目的:评价MRI多b值DWI序列在孤立性肺结节(SPN)良、恶性鉴别诊断中的价值。方法:选取2015年9月-2016年6月于我院行CT检查发现并未经治疗的78例SPN患者,在穿刺活检或手术前行MRI胸部检查,根据结节直径分为三组:D1≤10mm、10 mmD2≤20 mm、20 mmD3≤30 mm,DWI扫描b值(0 s/mm~2、400 s/mm~2、600 s/mm~2、800 s/mm~2)。分别测量不同b值下结节DWI图的信号评分和拟合ADC图的表观扩散系数(ADCtot值),参照病理结果进行对比分析。结果:在b值为400 s/mm~2时,良恶性结节DWI信号差异在D1组间无统计学意义(P0.05);当b值为600 s/mm~2时,良恶性结节DWI信号差异在(D1、D2、D3)组间均具有统计学意义(P0.05),且结节信号强度越高其恶性可能性越大;在b值为800 s/mm~2时,良恶性结节DWI信号差异在D3组间无统计学意义(P0.05);在良恶性结节ADCtot值对比分析中发现,不同良性结节的ADCtot值均较恶性结节偏高,差异具有统计学意义(P0.05);以3为信号阈值,1.50×10~(-3) mm~2/s为ADCtot阈值,对SPN的特异性、准确性、阳性预测值、阴性预测值均较信号强度评分升高(P0.05)。结论:MRI弥散加权成像评价SPN过程中,多b值拟合ADCtot值对病变良恶性鉴别能力较好。在b值为600 s/mm~2时,其信号强度差异对SPN的良恶性信号评价效能最佳,多b值DWI序列对SPN良恶性的鉴别诊断具有重要价值。     

磁共振弥散加权成像预测宫颈癌早期放化疗疗效及预后

目的:探讨磁共振弥散加权成像(DWI)在预测宫颈癌患者早期放化疗效果及预后的应用价值。方法:选择2011年2月~2014年2月在我院住院并接受同期放化疗的宫颈癌患者共74例,于放化疗前、放化疗中、放化疗结束时进行磁共振(MR)扫描及DWI检查。记录不同时间段的肿瘤体积和宫颈癌表观弥散系数(ADC)变化,依据实体瘤的疗效评价标准(RECIST)标准比较放化疗前后不同疗效组ADC值及其变化率。对患者进行18个月的随访,以病理切片检查结果为金标准,分析DWI对宫颈癌复发诊断的灵敏度和特异度。结果:放化疗前、中、结束时患者的肿瘤体积和ADC值差异具有统计学意义(P0.05);与放化疗前相比,不同疗效组放化疗后的ADC值均明显升高(P0.05),且放化疗后各组ADC值和ADC变化率之间差异均具有统计学意义(P0.05);DWI对宫颈癌复发诊断的灵敏度和特异度分别为95.83%和95.45%。结论:DWI可以预测宫颈癌早期放化疗临床疗效,并对患者预后评估具有较高的灵敏度和特异度,值得在临床上广泛推广。     

MR 弥散加权成像对鉴别诊断良恶性椎体压缩性骨折的临床价值研究

目的：探讨MR弥散加权成像(DWI)鉴别诊断良恶性椎体压缩性骨折的临床价值。方法：对57 例经临床或病理证实的椎体 良恶性压缩性骨折患者行矢状位T1WI、T2WI、T2WI/FS 及DWI扫描,研究其在常规序列和DWI序列上的表现,将常规MR 序列 和DWI序列检出率进行比较,测量正常椎体及病变椎体的表观弥散系数(ADC)值,并进行统计学分析。结果：(1)MR 常规序列和 DWI序列(b=500s/mm2)表现：良性椎体压缩性骨折呈长T1 长或等T2 改变,T2WI/FS 呈高信号,DWI 可以呈高信号、等信号及低 信号;恶性椎体压缩性骨折呈长T1 长T2 信号,大部分病灶T2WI/FS 及DWI呈高信号,少数变现为低信号;(2)MR 常规序列和 DWI 序列(b=500s/mm2)病灶检出率的比较：T1WI、T2WI/FS 及DWI序列病灶检出率均高于T2WI 序列,其间的差别有显著性意 义(P<0.01),T1WI、T2WI/FS 及DWI序列病灶检出率之间无显著性差异(P>0.01);(3)ADC 值比较：在DWI(b=500 s/mm2)上,良性组 ADC 值为(2.03± 0.83)× 10-3mm2/s,恶性组ADC 值为(1.37 ± 0.75)× 10-3mm2/s,正常组ADC值为(0.36± 0.21)× 10-3mm2/s,成像条 件相同时,良性组高于恶性组,两组间有明显的统计学意义(P<0.05)。结论：DWI可较好的反映椎体的弥散特征,ADC值作为量化 指标可对良恶性椎体压缩性骨折进行可靠鉴别。     

MR弥散加权成像对鉴别诊断良恶性椎体压缩性骨折的临床价值研究

目的：探讨MR弥散加权成像（DWI）鉴别诊断良恶性椎体压缩性骨折的临床价值。方法：对57例经临床或病理证实的椎体良恶性压缩性骨折患者行矢状位T1M、T2WI、T2WI／FS及DWI扫描,研究其在常规序列和DWI序列上的表现,将常规MR序列和DWI序列检出率进行比较,测量正常椎体及病变椎体的表观弥散系数（ADC）值,并进行统计学分析。结果：（1）MR常规序列和DWI序列（b=500s／mm2）表现：良性椎体压缩性骨折呈长T1长或等T2改变,T2WI／FS呈高信号,DWI可以呈高信号、等信号及低信号;恶性椎体压缩性骨折呈长T1长T2信号,大部分病灶T2WUFS及DWI呈高信号,少数变现为低信号;（2）MR常规序列和DWI序列（b=500s／mm2）病灶检出率的比较：T1WI、T2WI／FS及DWI序列病灶检出率均高于T2WI序列,其间的差别有显著性意义（P〈0．01）,T1WI、T2WI／FS及DWI序列病灶检出率之间无显著性差异（P〉0．01）;（3）ADC值比较：在DWI（b=500s／mm2）上,良性组ADC值为（2．03±0．83）×10^3mm^2/s,恶性组ADC值为（1．37±0．75）×10^-3mm^2/s,正常组ADC值为（0．36±0．21）×10^-3mm^2／s,成像条件相同时,良性组高于恶性组,两组间有明显的统计学意义（P〈0．05）。结论：DWI可较好的反映椎体的弥散特征,ADC值作为量化指标可对良恶性椎体压缩性骨折进行可靠鉴别。     

扩散加权成像在宫颈癌诊断中的应用及与病理相关性分析

目的:分析宫颈癌扩散加权成像特征及与病理相关性。方法:选取100例宫颈癌患者为观察组,100例健康志愿者为对照组,均接受磁共振检查。观察组患者均行病理学检查,并测定微血管密度。观察宫颈癌磁共振特征,并分析其与病理相关性。结果:1.磁共振共确诊宫颈癌97例,诊断符合率为97.0%。与病理分期比较,磁共振分期正确84例,正确率为84%。2.观察组宫颈癌病变区ADC值平均为(0.893±0.098)s/mm2,显著低于对照组的(1.623±0.132)s/mm2,差异具有统计学意义(P0.05)。病理分期Ⅲ、Ⅳ其病变ADC值及MVD值显著低于Ⅰ、Ⅱ期病变,差异具有统计学意义(P0.05)。经pearson相关分析,宫颈癌ADC值与MVD值间呈显著负相关(r=-0.502,P=0.011)。结论:在宫颈癌的诊断中,磁共振具有很高应用价值。宫颈癌病变于扩散加权成像呈高信号,其ADC值显著低于正常宫颈组织,且与MVD呈显著负相关。     

MSCT、DWI结合IL-10及CXCR7鉴别甲状腺乳头状癌与甲状腺腺瘤的诊断价值研究

摘要 目的：探讨多层螺旋计算机断层扫描（MSCT）、弥散加权成像（DWI）结合白介素-10（IL-10）及趋化因子受体7（CXCR7）对甲状腺乳头状癌（PTC）和甲状腺腺瘤（TA）的鉴别诊断效能以及最佳诊断方式。方法：纳入我院2019年3月至2021年10月甲状腺乳头状癌患者55例,甲状腺腺瘤患者32例。所有患者术前行MSCT、磁共振DWI影像检查,术后获取肿瘤组织,通过免疫组织化学方法检测肿瘤组织中IL-10及CXCR7表达情况。采用独立样本t检验比较两组间磁共振DWI、IL-10及CXCR7差异。应用ROC曲线比较磁共振DWI不同b值（300、500、800 s/mm²）对应的ADC值的诊断效能。分别对比MSCT、磁共振DWI、IL-10及CXCR7单独和联合检测对甲状腺乳头状癌与甲状腺腺瘤鉴别的诊断效能。结果：PTC组ADC值均低于TA组（P＜0.05）。当b值=500 s/mmP,PTC组和TA组ADC值分别为（1.509±0.546）×10^-3 mm/s和（2.477±0.667）×10^-3 mm/s,ROC曲线分析具有最佳诊断效能。当ADC截断值取1.529×10^-3 s/mmP时,其曲线下面积（AUC）为0.864（95％CI：0.783～0.945;P＜0.05）。IL-10、CXCR7在PTC组阳性表达率分别为81.82%、72.73%,均高于TA组6.25%、15.63%（P＜0.05）。所有CT征象（形态,边缘,密度,囊变,强化方式,增强后边界模糊与缩小改变,淋巴结肿大情况）在两组间均有差异（P＜0.05）。相比于单项检查方式,MSCT、磁共振DWI结合IL-10及CXCR7检查方式具有最高的敏感度89.09%、特异度88%、阳性预测值98.0%、阴性预测值83.78%、准确率91.95%以及约登指数0.860。结论：b=500 s/mm²的ADC值具有最高的诊断效能,相对于单一检查方式,MSCT、磁共振DWI结合IL-10及CXCR7对鉴别甲状腺乳头状癌与甲状腺腺瘤具有更优的诊断价值。     

动态对比增强磁共振成像在鼻咽癌分期中的应用价值

目的:分析动态对比增强磁共振成像(DCE-MRI)在鼻咽癌分期中的应用价值。方法:选取2016年6月至2018年4月我院经病理证实的初诊鼻咽癌患者104例为研究对象,均行DCE及扩散加权成像(DWI)检查,比较不同鼻咽癌分期患者的DCE-MRI定量参数[转运常数(Ktrans)、血管外细胞外间隙体积百分数(Ve)、速率常数(Kep)、容积分数(f PV)]及表观扩散系数(ADC)值,分析各DCE-MRI参数与临床分期的相关性,并评估DCE-MRI对鼻咽癌分期的诊断价值。结果:随总分期增加,鼻咽癌患者Ktrans、Ve增加,且Ve随T分期增加而增加,M1分期者Ktrans、Ve大于M0分期者(P0.05),不同N分期患者各DCE-MRI参数比较差异无统计学意义(P0.05),Kep、f PV在各分期中比较差异也无统计学意义(P0.05);随总分期增加,鼻咽癌患者ADC值减少(P0.05);Spearman相关分析发现,鼻咽癌患者Ktrans与总分期、M分期呈正相关,Ve与总分期、T分期呈正相关,ADC值与总分期呈负相关(P0.05);各参数中,Ktrans诊断鼻咽癌总分期的曲线下面积(AUC)最大,为0.925,Ktrans诊断鼻咽癌早期(Ⅱ期)、晚期(Ⅲ期与Ⅳ期)的AUC分别为0.909、0.921,均较ADC(AUC=0.864、0.815)高。结论:DCE-MRI在鼻咽癌临床分期中有较高应用价值,其中Ktrans的诊断效能最好且高于DWI诊断,肿瘤分期越高,Ktrans越大,可作为肿瘤分期的一个指标。     

Differentiating Laryngeal Carcinomas from Precursor Lesions by Diffusion-Weighted Magnetic Resonance Imaging at 3.0 T: A Preliminary Study

Background

Diffusion-weighted magnetic resonance imaging (DWI) has been introduced in head and neck cancers. Due to limitations in the performance of laryngeal DWI, including the complex anatomical structure of the larynx leading to susceptibility effects, the value of DWI in differentiating benign from malignant laryngeal lesions has largely been ignored. We assessed whether a threshold for the apparent diffusion coefficient (ADC) was useful in differentiating preoperative laryngeal carcinomas from precursor lesions by turbo spin-echo (TSE) DWI and 3.0-T magnetic resonance.

Methods

We evaluated DWI and the ADC value in 33 pathologically proven laryngeal carcinomas and 17 precancerous lesions.

Results

The sensitivity, specificity, and accuracy were 81.8%, 64.7%, 76.0% by laryngostroboscopy, respectively. The sensitivity, specificity, and accuracy of conventional magnetic resonance imaging were 90.9%, 76.5%, 86.0%, respectively. Qualitative DWI analysis produced sensitivity, specificity, and accuracy values of 100.0, 88.2, and 96.0%, respectively. The ADC values were lower for patients with laryngeal carcinoma (mean 1.195±0.32×10⁻³ mm²/s) versus those with laryngeal precancerous lesions (mean 1.780±0.32×10⁻³ mm²/s; P<0.001). ROC analysis showed that the area under the curve was 0.956 and the optimum threshold for the ADC was 1.455×10⁻³ mm²/s, resulting in a sensitivity of 94.1%, a specificity of 90.9%, and an accuracy of 92.9%.

Conclusions

Despite some limitations, including the small number of laryngeal carcinomas included, DWI may detect changes in tumor size and shape before they are visible by laryngostroboscopy. The ADC values were lower for patients with laryngeal carcinoma than for those with laryngeal precancerous lesions. The proposed cutoff for the ADC may help distinguish laryngeal carcinomas from laryngeal precancerous lesions.     

CT增强结合多b值DWI对胆总管炎性狭窄与肿瘤性病变所致狭窄的鉴别诊断研究

摘要 目的：探讨计算机断层扫描（CT）增强结合多b值弥散加权成像（DWI）对胆总管炎性狭窄与肿瘤性病变所致狭窄的鉴别诊断价值。方法：回顾性分析2017年4月-2021年10月于我院经手术病理或逆行胰胆管造影（ERCP）证实为胆总管炎性或肿瘤性狭窄的106例患者的临床资料,术前均行CT增强、多b值（200、400、600、800、1000 s/mm²）DWI的磁共振成像（MRI）检查并测量其多b值DWI下的ADC值,分析胆总管炎性狭窄与肿瘤性狭窄的影像表现,比较CT增强、多b值DWI单独及结合对胆总管炎性狭窄与肿瘤性狭窄的鉴别诊断效能。结果：106例患者中胆总管炎性狭窄共43例,肿瘤性狭窄患者共63例。当b值分别为200、400、600、800、1000 s/mm²时,胆总管肿瘤性病变ADC值均显著低于胆总管炎性狭窄,差异均具统计学意义（P＜0.05）,随着b值增加,其ADC值均减小。当b值分别取200、400、600、800、1000 s/mm²时,对应曲线下面积（AUC）分别为0.574、0.705、0.715、0.781、0.726,b值为800 s/mm²时诊断胆总管炎性狭窄与肿瘤性狭窄的效能最佳。CT增强结合多b值DWI对比CT增强或多b值DWI对胆总管炎性狭窄与肿瘤性狭窄的诊断效能最佳。结论：当多b值DWI取800 s/mm²时,CT增强结合多b值DWI可以显著提高胆总管炎性狭窄与肿瘤性狭窄的鉴别诊断价值,具有一定的临床应用价值。     

Dependence of apparent diffusion coefficient measurement on diffusion gradient direction and spatial position – A quality assurance intercomparison study of forty-four scanners for quantitative diffusion-weighted imaging

PurposeTo propose an MRI quality assurance procedure that can be used for routine controls and multi-centre comparison of different MR-scanners for quantitative diffusion-weighted imaging (DWI).Materials and methods44 MR-scanners with different field strengths (1 T, 1.5 T and 3 T) were included in the study. DWI acquisitions (b-value range 0–1000 s/mm²), with three different orthogonal diffusion gradient directions, were performed for each MR-scanner. All DWI acquisitions were performed by using a standard spherical plastic doped water phantom. Phantom solution ADC value and its dependence with temperature was measured using a DOSY sequence on a 600 MHz NMR spectrometer. Apparent diffusion coefficient (ADC) along each diffusion gradient direction and mean ADC were estimated, both at magnet isocentre and in six different position 50 mm away from isocentre, along positive and negative AP, RL and HF directions.ResultsA good agreement was found between the nominal and measured mean ADC at isocentre: more than 90% of mean ADC measurements were within 5% from the nominal value, and the highest deviation was 11.3%. Away from isocentre, the effect of the diffusion gradient direction on ADC estimation was larger than 5% in 47% of included scanners and a spatial non uniformity larger than 5% was reported in 13% of centres.ConclusionADC accuracy and spatial uniformity can vary appreciably depending on MR scanner model, sequence implementation (i.e. gradient diffusion direction) and hardware characteristics. The DWI quality assurance protocol proposed in this study can be employed in order to assess the accuracy and spatial uniformity of estimated ADC values, in single- as well as multi-centre studies.     

Preoperative Axillary Staging with 3.0-T Breast MRI: Clinical Value of Diffusion Imaging and Apparent Diffusion Coefficient

The axillary staging in newly diagnosed breast cancer is under major evolution. The aims of this study were to define the diagnostic performance of 3.0-T diffusion-weighted imaging (DWI) in the detection of axillary metastases in newly diagnosed breast cancer, to assess apparent diffusion coefficients (ADCs) for histopathologically confirmed metastatic lymph nodes in a clinical setting. Altogether 52 consecutive breast cancer patients underwent magnetic resonance imaging and DWI in addition to axillary ultrasound. ADCs of axillary lymph nodes were analysed by two breast radiologists and ultrasound-guided core biopsies were taken. In a separate reading by one radiologist two types of region of interests were used for a smaller group of patients. Altogether 56 axillae (121 lymph nodes) were included in the statistical analysis. Metastatic axillae (51.8%) had significantly lower ADCs (p<0.001). Mean ADCs were 0.663–0.676 x 10^-3 mm²/s for the histologically confirmed metastatic LNs and 1.100–1.225 x 10^-3 mm²/s for the benign. The sensitivity, specificity, and accuracy of DWI were 72.4%, 79.6%, and 75.9%, respectively with threshold ADC 0.812 x 10^-3 mm²/s. Region of interest with information on the minimum value increased the diagnostic performance (area under the curve 0.794 vs. 0.619). Even though ADCs are significantly associated with histopathologically confirmed axillary metastases the diagnostic performance of axillary DWI remains moderate and ultrasound-guided core biopsies or sentinel lymph node biopsies cannot be omitted.     

Non-Gaussian Analysis of Diffusion Weighted Imaging in Head and Neck at 3T: A Pilot Study in Patients with Nasopharyngeal Carcinoma

Purpose

To technically investigate the non-Gaussian diffusion of head and neck diffusion weighted imaging (DWI) at 3 Tesla and compare advanced non-Gaussian diffusion models, including diffusion kurtosis imaging (DKI), stretched-exponential model (SEM), intravoxel incoherent motion (IVIM) and statistical model in the patients with nasopharyngeal carcinoma (NPC).

Materials and Methods

After ethics approval was granted, 16 patients with NPC were examined using DWI performed at 3T employing an extended b-value range from 0 to 1500 s/mm². DWI signals were fitted to the mono-exponential and non-Gaussian diffusion models on primary tumor, metastatic node, spinal cord and muscle. Non-Gaussian parameter maps were generated and compared to apparent diffusion coefficient (ADC) maps in NPC.

Results

Diffusion in NPC exhibited non-Gaussian behavior at the extended b-value range. Non-Gaussian models achieved significantly better fitting of DWI signal than the mono-exponential model. Non-Gaussian diffusion coefficients were substantially different from mono-exponential ADC both in magnitude and histogram distribution.

Conclusion

Non-Gaussian diffusivity in head and neck tissues and NPC lesions could be assessed by using non-Gaussian diffusion models. Non-Gaussian DWI analysis may reveal additional tissue properties beyond ADC and holds potentials to be used as a complementary tool for NPC characterization.     

Tubo-Ovarian Abscess (with/without Pseudotumor Area) Mimicking Ovarian Malignancy: Role of Diffusion-Weighted MR Imaging with Apparent Diffusion Coefficient Values

Objective

To assess the added value of diffusion-weighted magnetic resonance imaging (DWI) with apparent diffusion coefficient (ADC) values compared to MRI, for characterizing the tubo-ovarian abscesses (TOA) mimicking ovarian malignancy.

Materials and Methods

Patients with TOA (or ovarian abscess alone; n = 34) or ovarian malignancy (n = 35) who underwent DWI and MRI were retrospectively reviewed. The signal intensity of cystic and solid component of TOAs and ovarian malignant tumors on DWI and the corresponding ADC values were evaluated, as well as clinical characteristics, morphological features, MRI findings were comparatively analyzed. Receiver operating characteristic (ROC) curve analysis based on logistic regression was applied to identify different imaging characteristics between the two patient groups and assess the predictive value of combination diagnosis with area under the curve (AUC) analysis.

Results

The mean ADC value of the cystic component in TOA was significantly lower than in malignant tumors (1.04 ± 0 .41 × 10⁻³ mm²/s vs. 2.42 ± 0.38 × 10⁻³ mm²/s; p < 0.001). The mean ADC value of the enhanced solid component in 26 TOAs was 1.43 ± 0.16×10⁻³mm²/s, and 46.2% (12 TOAs; pseudotumor areas) showed significantly higher signal intensity on DW-MRI than in ovarian malignancy (mean ADC value 1.44 ± 0.20×10⁻³ mm²/s vs.1.18 ± 0.36 × 10⁻³ mm²/s; p = 0.043). The combination diagnosis of ADC value and dilated tubal structure achieved the best AUC of 0.996. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of MRI vs. DWI with ADC values for predicting TOA were 47.1%, 91.4%, 84.2%, 64%, and 69.6% vs. 100%, 97.1%, 97.1%, 100%, and 98.6%, respectively.

Conclusions

DW-MRI is superior to MRI in the assessment of TOA mimicking ovarian malignancy, and the ADC values aid in discriminating the pseudotumor area of TOA from the solid portion of ovarian malignancy.     

Differentiation of Central Lung Cancer from Atelectasis: Comparison of Diffusion-Weighted MRI with PET/CT

Objective

Prospectively assess the performance of diffusion-weighted magnetic resonance imaging (DW-MRI) for differentiation of central lung cancer from atelectasis.

Materials and Methods

38 consecutive lung cancer patients (26 males, 12 females; age range: 28–71 years; mean age: 49 years) who were referred for thoracic MR imaging examinations were enrolled. MR examinations were performed using a 1.5-T clinical scanner and scanning sequences of T1WI, T2WI, and DWI. Cancers and atelectasis were measured by mapping of the apparent diffusion coefficients (ADCs) obtained with a b-value of 500 s/mm².

Results

PET/CT and DW-MR allowed differentiation of tumor and atelectasis in all 38 cases, but T2WI did not allow differentiation in 9 cases. Comparison of conventional T2WI and DW-MRI indicated a higher contrast noise ratio of the central lung carcinoma than the atelectasis by DW-MRI. ADC maps indicated significantly lower mean ADC in the central lung carcinoma than in the atelectasis (1.83±0.58 vs. 2.90±0.26 mm²/s, p<0.0001). ADC values of small cell lung carcinoma were significantly greater than those from squamous cell carcinoma and adenocarcinoma (p<0.0001 for both).

Conclusions

DW-MR imaging provides valuable information not obtained by conventional MR and may be useful for differentiation of central lung carcinoma from atelectasis. Future developments may allow DW-MR imaging to be used as an alternative to PET-CT in imaging of patients with lung cancer.     

磁共振成像对非小细胞肺癌的诊断价值分析

目的:探讨磁共振成像(Magnetic resonance imaging,MRI)对非小细胞肺癌的诊断价值。方法:选择2016年9月-2019年4月南京医科大学附属脑科医院(胸科院区)放射科收治的肺部结节患者74例,包括病理证实为肺部良性病变54例(良性组)和非小细胞肺癌20例(肺癌组)。所有患者都给予常规MRI、增强MRI与磁共振扩散加权成像(Diffusion weighted imaging,DWI),记录影像学特征并评估其诊断价值。结果:肺癌组的病灶形态、边缘等MRI特征与良性组对比差异无统计学意义(P0.05)。在b值=0、600、800、1000 s/mm~2条件下,肺癌组的病灶表观扩散系数(Apparent diffusion coefficient,ADC)值都显著低于良性组(P0.05)。肺癌组的病灶MRI增强Ⅰ型+Ⅱ型比例显著高于良性组(P0.05)。MRI鉴别诊断非小细胞肺癌的敏感性与特异性为98.1%和94.4%。结论:MRI用于非小细胞肺癌的诊断能反映病灶组织的血流动力学与水分子活动状况,具有较高的诊断敏感性与特异性。     

Prophylactic dendritic cell vaccination controls pancreatic cancer growth in a mouse model

PurposePancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer-related deaths with high recurrence after surgery due to a paucity of effective post-surgical adjuvant treatments. DC vaccines can activate multiple anti-tumor immune responses but have not been explored for post-surgery PDAC recurrence. Intraperitoneal (IP) delivery may allow increased DC vaccine dosage and migration to lymph nodes. Here, we investigated the role of prophylactic DC vaccination controlling PDAC tumor growth with IP delivery as an administration route for DC vaccination.MethodsDC vaccines were generated using ex vivo differentiation and maturation of bone marrow–derived precursors. Twenty mice were divided into four groups (n = 5) and treated with DC vaccines, unpulsed mature DCs, Panc02 lysates or no treatment. After tumor induction, mice underwent three magnetic resonance imaging scans to track tumor growth. Apparent diffusion coefficient (ADC), a quantitative magnetic resonance imaging measurement of tumor microstructure, was calculated. Survival was tracked. Tumor tissue was collected after death and stained with hematoxylin and eosin, Masson's trichrome, terminal deoxynucleotidyl transferase dUTP nick end labeling and anti-CD8 stains for histology.ResultsDC-vaccinated mice demonstrated stronger anti-tumor cytotoxicity compared with control groups on lactate dehydrogenase assay. DC vaccine mice also demonstrated decreased tumor volume, prolonged survival and increased ΔADC compared with control groups. On histology, the DC vaccine group had increased apoptosis, increased CD8+ T cells and decreased collagen. ΔADC negatively correlated with % collagen in tumor tissues.DiscussionProphylactic DC vaccination may inhibit PDAC tumor growth during recurrence and prolong survival. ΔADC may be a potential imaging biomarker that correlates with tumor histological features.