MR扩散加权成像中ADC值对肝脏肿瘤性病变的定性评估

目的评估MR扩散加权成像(DWI)对肝脏肿瘤性病变、特别是影像学表现不典型肿瘤性病变的诊断价值及其良恶性鉴别诊断价值。资料与方法对2010年8月至2011年5月的55例患者(34例为肿瘤患者怀疑有肝脏转移,21例CT、B超等影像学检查拟诊肝脏占位性病变无法进行定性诊断)行MR常规序列及DWI,共发现92个病灶(25个原发性肝癌,27个肝转移瘤,3个肝胆管细胞癌,2个肝硬化结节,2个肝脏局灶性结节增生,7个肝血管瘤,26个肝囊肿)。通过分析肝脏病灶信号强度随b值不同的变化及病灶表观扩散系数(ADC)值的大小(平均数±标准差)等对肝脏肿瘤性病变、特别是不典型肿瘤性病变的良恶性进行诊断及鉴别诊断,以病理结果或随访结果为标准计算其敏感性及特异性。结果 MR DWI上,b=50 s/mm2、500s/mm2及b=50 s/mm2、1000 s/mm2时,良性病变的信号衰减程度高于恶性病变,即b为50 s/mm2、1000 s/mm2时,恶性病变为高信号,而良性病变呈相对等信号或低信号,良恶性病灶信号强度差异明显。恶性病变的ADC值(b值为50 s/mm2、1000 s/mm2时计算)[(0.845±0.0110)×10-3mm2/s,n=55]明显低于良性病变的ADC值(b值为50 s/mm2、1000 s/mm2时计算)[(2.230±0.0497)×10-3mm2/s,n=37],经秩和检验差异具有统计学意义(Z=-7.905,P<0.01),敏感性及特异性分别为96.36%和83.78%。结论 DWI对肝脏肿瘤性病变、特别是影像学表现不典型肿瘤性病变具有较大诊断价值,对肝脏肿瘤性病变的良恶性鉴别诊断是一种简单、实用的影像学检查方法。     

b值对肝脏磁共振扩散加权成像ADC值及其可重复性的影响

目的 研究b值大小及数量对肝脏磁共振扩散加权成像(DWI)表观扩散系数(ADC)值大小及其可重复性的影响.资料与方法 对39例健康志愿者行肝脏DWI扫描,使用膈肌导航单次激发平面回波序列扫描2次,分别生成b值为(0、100)、(0、500)、(0、800)、(0、100、500)和(0、100、500、800) s/mm2的ADC图像.分别在左、右肝选取3个层面,然后在每个层面各选3个圆形感兴趣区(ROI)测量ADC值,分别以左、右肝9个ROI的平均ADC值代表左、右肝的ADC值.结果 b值相同时,左肝ADC值大于右肝(P＜0.001).b=0、100 s/mm2时ADC值最大;b=0、100、500、800 s/mm2时ADC值最小.Bland-Altman分析显示,b=0、100、500、800 s/mm2时可重复性最好(右肝:LOA=10.5％;左肝:LOA=13.9％).结论 b值越小,ADC值越大;使用多个b值计算的ADC值可重复性最高,在临床中测量肝脏DWI的ADC值时使用多个b值计算更为精确.     

磁共振成像对输尿管病变的诊断价值

目的:探讨MRI对输尿管病变的诊断价值。方法:回顾性分析经手术和病理证实的输尿管病变19例的MRI资料(均行平扫T1WI、T2WI,其中行增强扫描7例,行MRU检查11例),MRI结果与手术病理结果进行对照分析。结果:19例输尿管病变中原发性输尿管癌7例,膀胱癌侵及输尿管3例,肾结核累及输尿管4例,输尿管畸形4例,输尿管息肉1例。MRI对输尿管病变诊断的定位准确率为100%,定性准确率为94.7%。结论:MRI是用于输尿管疾病的一种很好的诊断方法,对肿瘤与炎症和良性与恶性肿瘤的鉴别、恶性肿瘤的TNM分期及输尿管畸形的详细情形可提供更全面的信息。     

子宫内膜癌的MRI诊断价值

目的：分析子宫内膜癌病人的MRI表现,评价MRI对子宫内膜癌的诊断价值。方法：对36例手术证实子宫内膜癌病人的MRI进行回顾性分析,依据FIGO分期原则,将术前MRI分期与术后病理结果进行比较研究。结果：以病理结果为基准,MRI判断肌层侵犯的准确率为77．8％（28／36）,分期准确率为86．1％（31／36）。结论：MRI能够清晰地显示子宫内膜癌的病灶范围及肌肉侵犯情况,术前诊断及分期价值较高,建议常规检查。     

The Relationship Between ADC of Diffusion-Weighted Magnetic Resonance Imaging and SUV of 18F-FDG PET/CT Metabolic Imaging in Lung Carcinoma

目的 研究肺癌MR扩散加权成像(DWI)表观扩散系数(ADC)与PET/CT代谢成像标准摄取值(SUV)的相关性.方法 搜集本院行胸部MR DWI和PET/CT代谢成像的26例肺癌患者的影像资料,分别测量MR DWI和PET/CT代谢成像对应层面病变实质部分的ADC最小值(ADCmin)、ADC平均值(ADCmean)和SUV最大值(SUVmax)、SUV平均值(SUVmean),计算相对ADC(rADC)(ADCmin/ADCmean)和相对SUV( rSUV)(SUVmax/SUVmean),分析ADCmin与SUVmax,ADCmean与SUVmean以及rADC与rSUV之间的相关性.结果 26例肺癌MR DWI的ADCmin为(0.891±0.167)×10-3mm2/s,ADCmean为(1.244±0.351)×10-3mm2/s,rADC为0.74±0.14;PET/CT代谢成像SUVmax为10.5±4.6,SUVmean为5.6±1.8,rSUV为1.80±0.28.ADCmin与SUVmax没有相关性(P =0.207 ＞0.05),ADCmean与SUVmean没有相关性(P=0.331 ＞0.05),rADC与rSUV呈负相关性(P =0.021 ＜0.05),相关系数为-0.451.结论 肺癌的MR DWI rADC与PET/CT代谢成像rSUV存在一定的负相关性,ADC与SUV在肺癌的临床应用中可以互为补充.     

Role of Interface Sign and Diffusion-Weighted Magnetic Resonance Imaging in Differential Diagnosis of Exophytic Renal Masses

PurposeWe aimed to investigate the role of interfaces of exophytic solid and cystic renal masses on magnetic resonance imaging (MRI) and the added value of diffusion-weighted imaging in differentiating benign from malignant lesions.MethodsThe Institutional Review Board approved this retrospective study, and informed consent was waived. A total of 265 patients (109 [41%] women and 156 [59%] men) with a mean age of 57 ± 12 (standard deviation) years were enrolled in this study. Preoperative MRI (n = 238) examinations of patients with solid or cystic renal masses and MRI (n = 27) examinations of patients with Bosniak IIF cysts without progression were reviewed. Solid/cystic pattern, interface types and apparent diffusion coefficient (ADC) values were recorded by 2 radiologists. The diagnostic performance of combining normalized ADC values with interface sign were evaluated.ResultsAmong 265 renal lesions (109 cystic and 156 solid), all malignant lesions (n = 192) had a round interface. No malignant lesions showed an angular interface. For prediction of benignity in cystic lesions, sensitivity (82.86% vs 56.16%), negative predictive value (92.50% vs 85.71%), and accuracy (94.50% vs 87.92%) ratios of angular interface were higher compared to all (solid plus cystic) lesions. The best normalized ADC cutoff values for predicting malignancy in lesions with round interface were as follows: for all (solid plus cystic), ≤ 0.75 (AUROC = 0.804); solid, ≤ 0.6 (AUROC = 0.819); and cystic, ≤ 0.8 (AUROC = 0.936).ConclusionsAngular interface can be a predictor of benignity for especially cystic renal masses. The evaluation of interface type with normalized ADC value can be an important clue in differential diagnosis especially in patients avoiding contrast.     

Diffusion-Weighted Magnetic Resonance Imaging Findings in a Patient with Trigeminal Ganglioneuroma

A case of intracranial ganglioneuroma arising from the trigeminal nerve in the pontine and cerebellopontine angle cistern, in a 44-year-old female, is presented with an emphasis on diffusion-weighted imaging findings. We will discuss on how the tumor in the very unusual location should be differentiated particularly focused on diffusion-weighted imaging findings.     

磁共振波谱成像对颅脑肿瘤的鉴别诊断价值

目的:分析脑肿瘤的氢质子磁共振波谱成像(1H-MRSI)改变,评价1H-MRSI对颅内常见肿瘤的诊断和鉴别诊断价值.方法:本组共42例颅内肿瘤患者行1H-MRSI检查,其中胶质瘤17例、脑膜瘤14例、脑转移瘤11例.测量比较3种肿瘤的实质强化区、周围水肿区和对侧正常脑组织的代谢物浓度(包括N-乙酰天门冬氨酸、肌酸和胆碱)并进行分析比较.结果:常规MRI检查T1WI上肿瘤多为等、低信号,T2WI上呈不均匀高信号,伴有不同程度强化和周围水肿.脑肿瘤的主要MRS袁现为NAA/Cho、NAA/Cr下降,Cho/Cr升高;3纽肿瘤周围水肿区的NAA/Cho分别为1.0167±0.314,1.4250±0.326和2.2900±1.186,组间比较差异均有显著性意义(P＜0.05);其它代谢物指标(NAA/Cr和Cho/Cr)在3种肿瘤间的差异无显著性意义(P＞0.05).3组肿瘤实质强化区各代谢物比值间差异无显著性意义(P＞0.05).结论:1H-MRSI可无创地分析脑肿瘤的代谢状况,对脑肿瘤的诊断、鉴别诊断均有很大的价值.     

肺癌MR扩散加权成像ADC与18F-FDG PET/CT代谢成像SUV的相关性研究

目的研究肺癌MR扩散加权成像(DWI)表观扩散系数(ADC)与PET/CT代谢成像标准摄取值(SUV)的相关性。方法搜集本院行胸部MR DWI和PET/CT代谢成像的26例肺癌患者的影像资料,分别测量MRDWI和PET/CT代谢成像对应层面病变实质部分的ADC最小值(ADCmin)、ADC平均值(ADCmean)和SUV最大值(SUVmax)、SUV平均值(SUVmean),计算相对ADC(rADC)(ADCmin/ADCmean)和相对SUV(rSUV)(SUVmax/SUVmean),分析ADCmin与SUVmax,ADCmean与SUVmean以及rADC与rSUV之间的相关性。结果 26例肺癌MR DWI的ADCmin为(0.891±0.167)×10-3mm2/s,ADCmean为(1.244±0.351)×10-3mm2/s,rADC为0.74±0.14;PET/CT代谢成像SUVmax为10.5±4.6,SUVmean为5.6±1.8,rSUV为1.80±0.28。ADCmin与SUVmax没有相关性(P=0.207>0.05),ADCmean与SUVmean没有相关性(P=0.331>0.05),rADC与rSUV呈负相关性(P=0.021<0.05),相关系数为-0.451。结论肺癌的MR DWI rADC与PET/CT代谢成像rSUV存在一定的负相关性,ADC与SUV在肺癌的临床应用中可以互为补充。     

Reduced Field-of-View Diffusion-Weighted Magnetic Resonance Imaging of the Pancreas: Comparison with Conventional Single-Shot Echo-Planar Imaging

ObjectiveTo investigate the image quality (IQ) and apparent diffusion coefficient (ADC) of reduced field-of-view (FOV) di-ffusion-weighted imaging (DWI) of pancreas in comparison with full FOV DWI.ResultsOn qualitative analysis, reduced FOV DWI showed better anatomic structure visualization (2.76 ± 0.79 at b = 0 s/mm² and 2.81 ± 0.64 at b = 400 s/mm²), lesion conspicuity (3.11 ± 0.99 at b = 0 s/mm² and 3.15 ± 0.79 at b = 400 s/mm²), IQ score (8.51 ± 2.05 at b = 0 s/mm² and 8.79 ± 1.60 at b = 400 s/mm²), and higher clinical utility (3.41 ± 0.64), as compared to full FOV DWI (anatomic structure, 2.18 ± 0.59 at b = 0 s/mm² and 2.56 ± 0.47 at b = 500 s/mm²; lesion conspicuity, 2.55 ± 1.07 at b = 0 s/mm² and 2.89 ± 0.86 at b = 500 s/mm²; IQ score, 7.13 ± 1.83 at b = 0 s/mm² and 8.17 ± 1.31 at b = 500 s/mm²; clinical utility, 3.14 ± 0.70) (p < 0.05). Artifacts were significantly improved on reduced FOV DWI (2.65 ± 0.68) at b = 0 s/mm² (full FOV DWI, 2.41 ± 0.63) (p < 0.001). On quantitative analysis, there were no significant differences between the 2 DWI sequences in ADCs of various pancreatic lesions and parenchyma (p > 0.05). ADCs of adenocarcinomas (1.061 × 10^-3 mm²/s ± 0.133 at reduced FOV and 1.079 × 10^-3 mm²/s ± 0.135 at full FOV) and neuroendocrine tumors (0.983 × 10^-3 mm²/s ± 0.152 at reduced FOV and 1.004 × 10^-3 mm²/s ± 0.153 at full FOV) were significantly lower than those of parenchyma (1.191 × 10^-3 mm²/s ± 0.125 at reduced FOV and 1.218 × 10^-3 mm²/s ± 0.103 at full FOV) (p < 0.05).ConclusionReduced FOV DWI of the pancreas provides better overall IQ including better anatomic detail, lesion conspicuity and subjective clinical utility.     

Clear Depiction of Inflammatory Abdominal Aortic Aneurysm with Diffusion-Weighted Magnetic Resonance Imaging

We report the case of an inflammatory abdominal aortic aneurysm incidentally detected clearly with diffusion-weighted magnetic resonance imaging (DW-MRI) during the examination of a patient with myelofibrosis with myeloid metaplasia that later converted to acute myeloid leukemia. DW-MRI revealed a hyperintense halo surrounding the abdominal aorta with aneurysmatic dilatation, establishing the diagnosis.     

急性阑尾炎MRI诊断的临床意义

目的 探讨急性阑尾炎的MRI表现及其临床意义.资料与方法 采用MRI SsH/T_2W-DRIVE序列、SsH/T_2WI序列、STIR/TSE序列和B-SPIR-TFE序列对20例临床诊断为急性阑尾炎和21例右下腹疼痛原因待查的患者进行MRI,采用统计学方法比较两组间差异,并与随后的手术结果进行对照.结果 急性阑尾炎在临床明确诊断组中,阑尾腔外径平均为(0.605±0.205)cm、平均壁厚(0.318±0.106)cm;在腹痛原因待查组中,阑尾腔外径平均为(0.613±0.185)cm、阑尾平均壁厚(0.354±0.179)cm,两者间差异无统计学意义.与手术结果对比,急性单纯性阑尾炎主要表现为阑尾壁T_2信号增高和无阑尾周局部积液;化脓性阑尾炎主要表现为阑尾腔扩张、阑尾腔T_2信号增高、阑尾壁增厚、阑尾壁T_2信号增高或有阑尾周围局部积液;而坏疽性阑尾炎表现与化脓性阑尾炎相似;阑尾脓肿则表现为阑尾消失和回盲部包裹性高信号.MR图像能清晰地显示阑尾的具体位置.结论 采用MRI不同序列检查,能在定位与分期诊断上为临床选择治疗方案和采取预防并发症的措施提供重要依据.     

Measurement of Water Diffusion in Hormone-Treated Rat Uteri by Diffusion-Weighted Magnetic Resonance Imaging

In this study, apparent water diffusion coefficients in hormone-treated rat uteri were measured by diffusion-weighted NMR imaging. Four groups of ovariectomized, mature young rats were treated with estrogen, progesterone, estrogen plus progesterone, or saline (as control). It was found that water diffusion is anisotropic in the myometrium, but not in the endometrium, and that it depends on hormonal conditions in the endometrium, but not in the myometrium. The anisotropy of water diffusion can be exploited to improve image contrast among the various uterine tissue types. The hormonal response suggests that diffusion imaging of human uterus may be useful in detecting endometrial pathology.     

SENSE基础上扩散加权成像诊断肝脏占位性病变的价值

目的探讨SENSE基础上扩散加权成像在诊断肝占位性病变中的应用价值以及表面扩散系数(ADC)评估肝占位病变的价值。方法对161例共有224个肝占位病灶患者在SENSE基础上行扩散加权成像。224个肝占位病灶中原发性肝癌80个,肝血管瘤45个,肝囊肿49个,转移性肝癌50个。应用梯度因子b值为0和50的扩散图像,并获取ADC值。结果原发性肝癌、肝血管瘤、肝囊肿和转移性肝癌的平均ADC值分别为(0.99±0.33)×10-3mm2/s、(1.99±0.30)×10-3mm2/s、(3.80±0.37)×10-3mm2/s和(1.08±0.29)×10-3mm2/s,前三者差异有极显著性意义(P<0.01)。原发性肝癌和转移性肝癌之间差异无显著性意义(P>0.05)。结论SENSE基础上扩散加权平面回波成像对肝癌(包括原发性肝癌和转移性肝癌)、肝血管瘤和肝囊肿的鉴别诊断具有较高的价值。     

大前庭水管综合征CT和MRI的应用价值

目的:探讨CT和MRI在诊断大前庭水管综合征(LVAS)中的应用价值。方法:10例LVAS患者行CT和MRI检查,在CT多平面重组(MPR)图像上分别测量前庭水管(VA)中点最宽径及外口直径,并应用容积再现(VR)技术进行三维重组;MRI检查均使用3D-FIESTA序列,在MPR图像上分别测量内淋巴囊(ES)骨内部分中点最宽径及外口直径,并应用VR三维重组技术。2组中点最宽径及外口直径分别行相关性检验和配对t检验。结果:10例LVAS患者CT均显示双侧扩大的VA,MRI显示双侧扩大的ES。CT测得VA中点及外口平均直径分别为1.935和2.935 mm,MRI相应测量值为1.880和3.115mm.2组的这2项测量结果均具有相关性(P<0.05)。VR图像能立体直观地显示扩大的VA及ES。结论:CT和MRI检查均可以正确诊断LVAS,MPR及VR重组图像可清晰地显示扩大的VA和ES。     

Diffusion-Weighted Magnetic Resonance Imaging of the Breast: Standardization of Image Acquisition and Interpretation

Diffusion-weighted (DW) magnetic resonance imaging (MRI) is a rapid, unenhanced imaging technique that measures the motion of water molecules within tissues and provides information regarding the cell density and tissue microstructure. DW MRI has demonstrated the potential to improve the specificity of breast MRI, facilitate the evaluation of tumor response to neoadjuvant chemotherapy and can be employed in unenhanced MRI screening. However, standardization of the acquisition and interpretation of DW MRI is challenging. Recently, the European Society of Breast Radiology issued a consensus statement, which described the acquisition parameters and interpretation of DW MRI. The current article describes the basic principles, standardized acquisition protocols and interpretation guidelines, and the clinical applications of DW MRI in breast imaging.     

Distal Embolization After Stenting of the Vertebral Artery: Diffusion-Weighted Magnetic Resonance Imaging Findings

Purpose We retrospectively evaluated our experience with stenting of the vertebral artery in an effort to determine the risk of distal embolization associated with the procedure. Methods Between June 2000 and May 2005, 35 patients with 38 stenting procedures for atherosclerotic disease of the vertebral origin in our institution were identified. The average age of the patients was 60.3 years (range 32–76 years). Sixteen of these patients (with 18 stents) had MR imaging of the brain with diffusion-weighted imaging and an apparent diffusion coefficient map within 2 days before and after procedure. Results On seven of the 16 postprocedural diffusion-weighted MR images, a total of 57 new hyperintensities were visible. All these lesions were focal in nature. One patient demonstrated a new diffusion-weighted imaging abnormality in the anterior circulation without MR evidence of posterior circulation ischemia. Six of 16 patients had a total of 25 new lesions in the vertebrobasilar circulation in postprocedural diffusion-weighted MR images. One patient in this group was excluded from the final analysis because the procedure was complicated by basilar rupture during tandem stent deployment in the basilar artery. Hence, new diffusion-weighted imaging abnormalities were noted in the vertebrobasilar territory in 5 of 15 patients after 17 stenting procedures, giving a 29% rate of diffusion-weighted imaging abnormalities per procedure. No patient with bilateral stenting had new diffusion-weighted imaging abnormalities. Conclusion Stenting of stenoses of the vertebral artery origin may be associated with a significant risk of asymptomatic distal embolization. Angiography, placement of the guiding catheter, inflation of the stent balloon, and crossing the lesion with guidewires or balloon catheters may potentially cause distal embolization. Further studies to evaluate measures to increase the safety of vertebral artery stenting, such as the use of distal protection devices or short-term postprocedural anticoagulation, should be considered for patients with clear indications for this procedure.     

双b值扩散加权成像在脑梗死诊断中的应用

目的:比较双b值DWI对脑梗死体积及ADC值测量的影响,探讨较高b值DWI在脑梗死诊断中的应用价值。方法:回顾性研究30例脑梗死患者,年龄44～84岁,平均67岁,发病时间3～6d,DWI取b值1000和2000s/mm2,分析脑梗死DWI及ADC图,测量兴趣区与对侧正常部位的扩散系数(ADC)并计算相对扩散系数(rADC),测量并计算梗死灶体积。结果:急性和亚急性脑梗死灶均扩散受限,DWI呈高信号、ADC图呈低信号。与b值1000s/mm2相比,b值2000s/mm2DWI示脑灰白质对比度增加,病灶显示更清晰,还能发现新病灶。不同b值下rADC比较没有统计学意义(P=0.884,P>0.05),同侧ADC有统计学意义(P=0.005,P<0.05);对侧ADC有显著统计学意义(P<0.001)。较高b值下梗死体积较低b值增加,且有统计学意义(P=0.04,P<0.05)。结论:DWI是检测脑梗死的重要技术手段,rADC不受b值影响,rADC降低可指导脑梗死诊断;较高b值DWI上脑梗死灶体积测量更准确,有利于观察病灶演变和指导临床治疗。