3.0T磁共振扩散加权成像诊断直肠癌最适b值的选取

目的对直肠癌患者行3.0T磁共振不同b值的扩散加权成像,选取显示直肠癌的最适b值。方法对75例术后确诊的直肠癌患者分别行b=800、1 000、1 200、1 500 s/mm2与1 800 s/mm2五组扩散加权成像,分别将不同b值的各组间肿瘤本身SNR、肿瘤与肌肉的对比噪声比CNR和肿瘤与脂肪的CNR作比较。结果 SNR、CNR值均呈正态分布,b值为1 200 s/mm2与1 500 s/mm2时SNR、CNR差异无显著性意义(P>0.05),但低于b值1 200 s/mm2及高于1 500 s/mm2的差异均有显著性意义(P<0.05)。结论超高场3.0T磁共振扩散加权成像诊断直肠癌的b值选取1 200 s/mm2和1 500 s/mm2较合适。     

直肠癌3.0T磁共振扩散加权成像中b值的选择

目的:选择直肠癌3.0T磁共振扩散加权成像(DWI)的合适b值,以利于DWI对直肠癌病灶的检出.方法:对63例直肠癌患者行多b值DWI检查(b值为300、600、900、1200、1500、1800、2100 s/mm2)及常规MRI平扫(T2 WI、T1 WI).测量不同b值时直肠癌的ADC值;计算直肠癌的信噪比(SNR)及膀胱的信号强度比(SIR);根据HE染色病理图片记录直肠癌的细胞密度,并进行统计学分析.结果:随着b值的增大,直肠癌ADC值及SNR呈逐渐降低趋势,差异有统计学意义(P＜0.05).当b值≤1200 s/mm2时,DWI图像中直肠癌SNR均高于T2 WI图像(P＜0.05).各不同b值的DWI图像中膀胱SIR均低于T2WI图像(P＜0.05),随着b值的增大膀胱SIR逐渐减低,当b值≥1200 s/mm2时,膀胱SIR明显减低接近于1.不同b值时直肠癌ADC值与细胞密度之间均呈负相关(P＜0.05),b=1200 s/mm2时,其相关度最高(r=-0.76,P＜0.05).结论:直肠癌3.0T磁共振扩散加权成像中的合适b值应为1200 s/mm2.     

直肠癌术前3.0T MR扩散加权成像b值的优化

目的 比较不同扩散敏感系数(b值)对直肠癌病变的显示及对背景的抑制能力,探讨直肠癌术前3.0TMR扩散加权成像(DWI)的合理b值.方法 经病理证实直肠癌36例,术前行3.0 T MR DWI,b值取500、800、1000、1200、1500 s/mm2.分析各b值对肿瘤信号强度(ST),肿瘤信噪比(SNR),肿瘤与直肠系膜(CNRT/F)、肿瘤与盆壁肌肉(CNRT/M)等对比噪声比(CNR)的影响,以及各b值对肿瘤病变的显示及对背景的抑制能力.结果 ST、SNR、CNRT/F及CNRT/M分别在b值为1000 s/mm2～1200 s/mm2之间差异无明显统计学意义(P =0.22,P=0.119,P=0.102,P=0.161),而在b值＜1000或＞1200 s/mm2时差异有明显统计学意义(P＜0.05).在各b值对肿瘤病变的显示及对背景的抑制能力判定中,主观评分在b值为1000 s/mm2～ 1200 s/mm2之间及1200 s/mm2～1500s/mm2之间差异无明显统计学意义(P =0.067、P--0.110),而在b值＜1000 s/mm2时差异有明显统计学意义(P＜0.05).结论 当b值取1000或1200 s/mm2时,既能获得良好的DWI图像,又能满足诊断需求,可作为直肠癌术前3.0 TMR扩散加权成像的合理b值.     

MRI及MR扩散加权成像对诊断局部复发性直肠癌的价值

目的评价标准MRI、MR扩散加权成像(DWI)及融合影像对于一些临床怀疑肿瘤复发病人的局部直肠癌复发的诊断的准确性。方法对临床怀疑肿瘤复发的42例病人应用1.5TMR设备进行检查,包括标准T2加权快速回波序列(3个方向)及横断位DWI序列(b=0,500,1000)。2名阅片者(R1,R2)独立对下列3组影像进行阅片并对肿瘤复发的     

磁共振扩散加权成像对前列腺癌的诊断价值

目的:评价MR扩散加权成像对前列腺癌的诊断价值。方法:搜集有手术或穿刺病理结果的前列腺疾病患者15例,其中前列腺癌10例,前列腺炎5例。所有病例均行MR常规T1WI、T2WI及DWI扫描。回顾性分析各组病例的MR常规表现及DWI表现。结果:在MR扩散加权图像上,8例前列腺癌表现为外周带内局限性显著高信号,其余病变在扩散加权成像上为低信号或等信号。结论:MR扩散加权成像对前列腺癌有重要的鉴别诊断价值。     

磁共振扩散加权成像在直肠肿瘤性病变诊断中的价值

目的：通过对不同类型直肠肿瘤病例DWI图像分析和ADC值的测量探讨扩散加权成像对直肠肿瘤性病变的诊断价值。方法比较8例直肠腺瘤,30例中分化腺癌,6例低分化腺癌,7例黏液腺癌,6例淋巴瘤及5例间质瘤的ADC值的差异。结果①直肠淋巴瘤的ADC值明显低于直肠癌、直肠腺瘤,差异有统计学意义（ P＜0．05）,淋巴瘤与间质瘤之间差异无统计学意义（ P ＞0．05）;②直肠腺瘤ADC值低于粘液腺癌（ P ＜0．05）,与间质瘤、腺癌之间差异无统计学意义（ P＞0．05）;③间质瘤 ADC值低于粘液腺癌（ P ＜0．05）,与淋巴瘤、腺癌、腺瘤之间差异无统计学意义（ P ＞0.05）;④粘液腺癌ADC值高于中分化腺癌（ P ＜0．05）,与低分化腺癌之间差异无统计学意义（ P ＞0．05）,中分化、低分化腺癌之间差异无统计学意义（ P ＞0．05）。结论扩散加权成像对不同类型直肠肿瘤、不同类别的直肠腺癌具有一定的鉴别诊断价值,联合MR常规扫描可提高诊断效能。     

薄层MRI联合MR扩散加权成像对直肠癌术前局部分期的价值

目的 以病理分期作为金标准,探讨薄层MRI联合MR扩散加权成像(DWI)对直肠癌术前局部分期的价值.资料与方法 对首诊直肠癌的40例患者进行前瞻性研究.40例均行常规MRI、薄层MRI和DWI后手术治疗并行病理分期.结果 薄层MRI较常规MRI能更好地显示肠壁的各层解剖结构及肿瘤对肠壁及邻近结构的侵犯范围和程度.常规MRI、薄层MRI联合DWI两种检查方法行IN分期的准确性分别为45％和67.5％,差异有统计学意义(P =0.044);T分期的准确性分别为65％和85％,差异有统计学意义(P=0.040);N分期的准确性分别为65％和75％,差异无统计学意义(P=0.332).结论 薄层MRI联合DWI在直肠癌术前局部分期(TN分期)方面优于常规MRI,特别是在T分期方面,薄层MRI联合DWI更具优势,准确性提高到85％;在N分期方面,薄层MRI联合DWI与常规MRI相比无明显差别.     

3.0 T磁共振扩散加权成像在直肠癌诊断中的价值

目的 探讨MR扩散加权成像(DWI)在直肠癌诊断中的临床应用价值.资料与方法对50例直肠癌患者和17名无直肠病变的自愿者行盆腔T2WI和DWI,由两名放射诊断医师采用肓法随机进行MRI阅片后对比分析单纯T2WI与T2WI结合DWI对直肠癌诊断的特异性和敏感性差异,并对直肠癌和正常肠壁的表观扩散系数(ADC)值进行定量分析.结果两名医师单纯应用T2WI与T2WI结合DWI检出直肠癌的ROC曲线下面积(Az)值分别为0.873与0.978(P＜0.05)、0.905与0.986(P＜0.05).Kappa一致性检验表明两名医师具有良好的一致性(Kappa值分别为0.860和0.828,P＜0.05).直肠癌和其癌周正常肠壁ADC值的平均值±标准差分别为(0.93±0.14)×10-3 mm2/s、(1.40±0.17)×10-3 mm2/s,直肠癌与正常肠壁的ADC值间差异有统计学意义(t=17.43,P＜0.01).结论 3.0 T MR DWI能较直观地显示直肠癌,其作为常规T2WI的补充检查序列可以明显提高对直肠癌的检出率.     

MRI平扫结合扩散加权成像在直肠癌中的临床应用价值

目的:探讨MRI平扫结合扩散加权成像(DWI)在直肠癌中的临床应用价值.方法:对28例直肠癌患者行MRI平扫及DWI检查,评价肿瘤形态、T分期、淋巴结转移、环周切缘(CRM)状态、肿瘤下缘距肛缘的距离,并与术后病理结果进行对照.MRI与病理对T分期、N分期及环周切缘受累评估的一致性采用Kappa检验.结果:MRI平扫及DWI能准确显示肿瘤的部位及形态.MRI平扫结合DWI对28例直肠癌T分期总的诊断符合率为78.57％(22/28),T1～T2期、T3期、T4期的诊断符合率分别为85.71％、78.57％、92.86％,MRI与病理对T分期的诊断具有较高的一致性(Kappa值=0.656).MRI平扫结合DWI对判断N分期的符合率为71.43％ (20/28),判断淋巴结转移的敏感度为66.67％(6/9),特异度为73.68％(14/19),MRI与病理对N分期的诊断具有中度一致性(Kappa值=0.489).MRI判定CRM状态的总体符合率为85.71％ (24/28),敏感度为90.90％(10/11),特异度为82.35％(14/17),阳性预测值为76.92％(10/13),阴性预测值为93.33％(14/15),MRI与病理对环周切缘受累的评估具有较高的一致性(Kappa值=0.710).MRI矢状面图像能测量18例下段直肠癌肿瘤下缘距肛缘的曲线距离.结论:MRI平扫结合DWI对直肠癌、T分期、环周切缘状态的判断及肿瘤下缘距肛缘的距离的测量有重要临床价值.     

磁共振扩散加权成像在胆管癌诊断中的价值研究

目的:探讨磁共振扩散加权成像(DWI)对胆管癌及肝良、恶性占位性病变的鉴别诊断价值。材料和方法:对50例健康志愿者、25例胆管癌患者及59例肝局灶性占位性病变患者行DWI检查,并测量表观扩散系数(ADC值)。本研究胆管癌组仅包括肝内胆管细胞癌及肝门部胆管癌,肝良、恶性占位组包括肝细胞癌10例,肝转移瘤11例,肝血管瘤20例及肝囊肿18例。所有患者同时作多期动态增强MRI,通过观察病灶各期强化特点,进一步为定性诊断提供依据。结果:正常肝组织ADC值(单位:mm2/1000s)为1.46±0.23,胆管癌、肝细胞癌及肝转移瘤的ADC值分别为1.31±0.09,1.24±0.16,1.26±0.22,三者之间差异无统计学意义(P>0.05);肝血管瘤、肝囊肿ADC值分别为1.83±0.33,3.34±0.59;以上恶性肿瘤ADC值均低于良性病变,即胆管癌的ADC值与肝良性病变之间有显著性差异(P<0.01)。在动态增强扫描中,35.2%肝癌、80%胆管癌与36%转移瘤病灶可见门静脉期及延迟期强化。结论:DWI分析及ADC值测量对胆管癌及肝局灶性良性病变的鉴别诊断有一定价值,可作为一种肝、胆脏器MRI的补充检查序列。     

The value of diffusion-weighted imaging in combination with T2-weighted imaging for rectal cancer detection

OBJECTIVE: To evaluate the clinical value of diffusion-weighted imaging (DWI) in combination with T(2)-weighted imaging (T(2)WI) for the detection of rectal cancer as compared with T(2)WI alone. MATERIALS AND METHODS: Forty-five patients with rectal cancer and 20 without rectal cancer underwent DWI with parallel imaging and T(2)WI on a 1.5 T scanner. Images were independently reviewed by two readers blinded to the results to determine the detectability of rectal cancer. The detectability of T(2)W imaging without and with DW imaging was assessed by means of receiver operating characteristic analysis. The interobserver agreement between the two readers was calculated with kappa statistics. RESULTS: The ROC analysis showed that each of two readers achieved more accurate results with T(2)W imaging combined with DW imaging than with T(2)W imaging alone significantly. The A(z) values for the two readers for each T(2)WI and T(2)WI combined with DWI were 0.918 versus 0.991 (p=0.0494), 0.934 versus 0.997 (p=0.0475), respectively. The values of kappa were 0.934 for T(2)WI and 0.948 for T(2)WI combined with DWI between the two readers. CONCLUSION: The addition of DW imaging to conventional T(2)W imaging provides better detection of rectal cancer.     

MRI在直肠癌术前T分期中的误判分析

目的:探讨MRI在直肠癌术前T分期中的常见误判原因。方法:选择32例经手术病理证实的直肠癌患者,术前均行MRI检查,MRI序列包括常规T1WI、T2WI及STIR。分析直肠癌患者MRI分期,并对照患者术后病理学分期,评估其一致性。结果:直肠癌的术前MRI分期与术后病理学分期的一致性较好(Kappa=0.64,P<0.001)。MRI术前分期误判率为25%,其中,4例pT2期(病理分期为T2期)过度分期为T3期;3例pT3期(病理分期为T3期)低分期为T2期,1例pT3期过度分期为T4期。结论:在直肠癌MRI术前T分期中,正确认识常见误判原因有利于临床治疗方案的制定。     

直肠癌术前MRI对异时远处转移的预测价值评估

目的:探讨直肠癌术前MRI对异时远处转移的预测价值.方法:回顾性分析291例经手术病理证实为直肠癌患者治疗前的MR资料及随访资料,分析直肠癌MR征象与异时远处转移的相关性,分析异时远处转移的独立危险因素,并与病理结果进行对照.结果:291例患者中69例(23.7％)发生异时远处转移.单因素分析结果表明治疗前癌胚抗原(CEA)水平(P＜0.001)、mrT分期(P=0.037),mrN分期(P＜0.001)和环周切缘状态(mrCRM) (P＜0.001)与直肠癌异时远处转移具有相关性.多因素分析结果显示CEA升高(P＜0.001)、mrN2期(P=0.013)和mrCRM(P=0.001)受侵是直肠癌异时远处转移的独立危险因素.相比于mrN0患者,mrN1和mrN2期患者发生异时远处转移的危险比值比(OR值)分别为1.93和2.60.病理结果亦证实N分期为远处转移的危险因素.结论:直肠癌术前mrN分期是直肠癌异时远处转移的独立危险因素,有助于筛选远处转移的高危患者,从而采取个性化治疗,以提高预后.     

Diffusion MRI for rectal cancer staging: ADC measurements before and after ultrasonographic gel lumen distension

ObjectivesTo compare Apparent Diffusion Coefficient (ADC) measurements in rectal neoplastic lesions before and after lumen distension obtained with sonography transmission gel.MethodsFrom January 2014 to July 2016, 25 patients (average age 63.7, range 41–85, 18 males) were studied for pre-treatment rectal cancer staging using a 1.5 T MRI. Diffusion MRI was obtained using echo-planar imaging with b = 800 value; all patients were studied acquiring diffusion sequences with and without rectal lumen distension obtained using sonography transmission gel. In both diffusion sequences, two blinded readers calculated border ADC values and small ADC values, drawing regions of interest respectively along tumour borders and far from tumour borders. Mean ADC values among readers − for each type of ADC measurement − were compared using Wilcoxon matched pairs signed rank test. Correlation was assessed using Pearson analysis.ResultsBorder ADC mean value for diffusion MR sequences without endorectal contrast was 1.122 mm²/sec, with 95% Confidence Interval (CI) = 1.02–1.22; using gel lumen distension, higher border ADC mean value of 1.269 mm²/s (95% CI = 1.16–1.38) was obtained. Wilcoxon matched pairs signed rank test revealed statistical difference (p < 0.01); a strong Pearson correlation was reported, with r value of 0.69. Small-ADC mean value was 1.038 mm²/s (95% CI = 0.91–1.16) for diffusion sequences acquired without endorectal distension and 1.127 mm²/s (95% CI = 0.98–1.27) for diffusion sequences obtained after endorectal gel lumen distension. Wilcoxon analysis did not show statistical difference (p = 0.13). A very strong positive correlation was observed, with r value of 0.81.ConclusionsADC measurements are slightly higher using endorectal sonographic transmission gel; ROI should be traced far from tumour borders, to minimize gel filled-pixel along the interface between lumen and lesion. Further studies are needed to investigate better reliability of ADC in rectal cancer MRI using sonographic gel intraluminal distension.     

直肠癌MRI术前评估价值与术后病理对比研究

目的 探讨MRI对直肠癌术前评估的价值。方法 选取84例行外科手术治疗的直肠癌患者的MRI、病理、临床资料。用卡方检验评价MRI对诊断肿瘤T分期、N分期、环周切缘（CRM）受累情况、壁外血管浸润的准确性,用配对t检验评估MRI分析病灶与齿状线位置关系的准确性。结果 MRI可较准确地评估对诊断肿瘤T分期、N分期、环周切缘受累情况、壁外血管浸润状态（P<0.01）,可大致评估低位直肠癌病灶距齿状线距离（P> 0.05）。结论 MRI可较准确地评估对诊断肿瘤T分期、N分期、环周切缘受累情况、壁外血管浸润状态。受测量习惯、测量误差、肠管走行等因素的影响,MRI可大致评估病灶距齿状线距离,且测量误差在外科可接受范围内。MRI为临床手术选择及术前评估提供了有价值的影像学依据。     

Value of diffusion-weighted images in diagnosis of locoregionally recurrent rectal tumors

IntroductionTo assess the value of referring to Diffusion-weighted images in evaluation of T2-weighted images of patients clinically suspicious of locoregional rectal cancer recurrence.MethodsAfter ethics committee approval and informed consent were obtained, 37 consecutive patients (male/female of 22/15; mean age 56 ± 13.5 SD) clinically suspicious of recurrent rectal tumor were prospectively included in the study over a two-year period. T2-weighted images of the patients were reviewed and the results were recorded. Right after that, the corresponding DWI images were provided for the radiologist and new ratings were given to the patients after taking into account the DWI findings. Finally, the patients underwent tissue biopsy. Receiver Operating Characteristic (ROC) analysis was performed, and Area Under the Curve (AUC) of the “T2-weighted alone” and “T2-weighted + DWI” methods were calculated and compared.Results“T2-weighted alone” and “T2-weighted + DWI” methods had an AUC of 0.64 (95% CI 0.47 to 0.79) and 0.75 (95% CI 0.58 to 0.88), respectively. The Difference between the two AUCs was 0.11 (P = 0.16). In the subgroup of patients having equivocal ratings in T2-weighted images, DWI images correctly identified 81% (13/16) of patients with true tumor recurrence and 66% (8/12) of patients without recurrence.ConclusionOur results suggest that referring to DWI does not significantly change the overall diagnostic performance of T2-weighted images. However, DWI is of great value in evaluation of the subgroup of patients with equivocal findings in T2-weighted images. Studies with larger sample sizes are needed to confirm these findings.Implications for practiceWhen T2-weighted images are equivocal, DWI images may be helpful in evaluation of patients with suspected locoregional recurrence of rectal tumor.     

直肠MRI对直肠癌术前T分期评估的研究进展

直肠MRI是直肠癌术前分期的首选检查方法。高分辨T2WI可显示直肠癌的位置、形态及信号,通过判别肿瘤的浸润深度来评估直肠癌的T分期;还可以识别直肠癌壁外血管内侵犯、环周切缘阳性等预后不良因素,从而指导选择最佳治疗方案。增强T1WI可显示病变区是否存在完整的黏膜下强化带,结合形态学特征准确地区分T1及T2期肿瘤。基于直肠壁各层及周围结构的MRI征象,对直肠MRI评估直肠癌术前局部T分期的研究进展进行综述。     

高分辨率MRI扩散加权成像对直肠癌术前T、N分期及环周切缘判断的价值

目的 探讨高分辨率MRI扩散加权成像(DWI)对直肠癌患者术前T、N分期与环周切缘的判断价值.方法 对收治的直肠癌127例患者行MRI与DWI检查,根据术后病理结果,分析MRI与DWI对直肠癌术前T分期与N分期的诊断价值以及对环周切缘的判断价值.结果 MRI诊断T1期敏感度92.00％、特异度99.02％;T2期敏感度...