正常成人腰椎间盘的DWI初步研究

目的：应用DWI探讨正常成人腰椎间盘髓核平均ADC值的正常值,并分析椎间盘髓核平均ADC值随年龄及解剖位置的变化规律。方法：收集行腰椎间盘髓核MRI检查的成人健康志愿者53例。测量并记录志愿者的各椎间盘髓核ADC值。结果：53例腰椎间盘髓核平均ADC值为（1.73±0.24）×10^-3 mm²/s,不同解剖层面的腰椎间盘髓核平均ADC值差异无统计学意义（P>0.05）。18~30岁组、31~45岁组、46~60岁组的腰椎间盘髓核ADC值分别为（1.88±0.15）×10^-3 mm²/s、（1.75±0.11）×10^-3 mm²/s、（1.55±0.19）×10^-3 mm²/s,3个年龄组差异有统计学意义（P<0.05）。结论：腰椎间盘的解剖位置对正常成人腰椎间盘髓核平均ADC值影响不大,但随着年龄增长,ADC值有降低趋势。     

DWI对宫颈癌化疗效果的评价

目的：探讨ADC值在宫颈癌化疗效果预测中的应用价值。方法：收集43例Ⅱa期以上宫颈癌患者,均接受化疗,在化疗前、化疗2～3周及化疗结束后行常规MRI及DWI检查,测量治疗前后不同时间点肿瘤最大径和ADC值,分析ADC值差异性,以及与肿瘤最大径缩小率的相关性。结果：宫颈癌化疗后ADC值升高,化疗前、化疗2～3周及结束时ADC值两两比较差异均有统计学意义（均P<0.01）;化疗前与化疗2～3周的ADC值差值（T值）为（0.43±0.12）×10^-3 mm²/s,化疗前后肿瘤最大径缩小率为（80±11）%,T值与肿瘤最大径缩小率呈正相关（P<0.05）。结论：宫颈癌病灶的ADC值在化疗后升高,且早期升高幅度与肿瘤最大径缩小率呈正相关,可作为预测宫颈癌化疗效果的理想手段之一。     

3.0T磁共振扩散加权成像在前列腺癌诊断与鉴别诊断中的应用

 目的 探讨3.0T磁共振弥散加权成像(DWI)和表面弥散系数(ADC)在前列腺癌诊断及鉴别诊断中的应用价值。方法 回顾性分析65例经穿刺活检病理证实的前列腺疾病患者,其中前列腺癌组21例,前列腺炎组19例,良性前列腺增生(BPH)组25例,测量病变区及前列腺增生外周带的ADC值,并在癌与非癌组之间进行受试者操作特征曲线(ROC)分析。结果 前列腺癌组ADC值为(0.74±0.10)×10^-3 mm²/s,前列腺炎组为(0.98±0.07)×10^-3 mm²/s, BPH组中央带为(1.21±0.09)×10^-3 mm²/s,外周带为(1.38±0.14)×10^-3 mm²/s,组间ADC值两两比较,差异均有统计学意义(P<0.01)。根据ROC曲线,当ADC值为0.95×10^-3 mm²/s时,诊断的敏感性达92.8%,特异性达100%,ROC曲线下面积为0.995。结论 磁共振DWI和ADC值可用于前列腺癌的诊断和鉴别诊断,具有很高的临床应用价值。     

ADC值和相对ADC鉴别乳腺良恶性病变的价值

目的探讨ADC值和相对ADC(relative ADC,rADC)鉴别乳腺良恶性病变的价值。方法回顾性分析2011年1月~2018年12月济宁医学院附属医院通过病理或活检证实的乳腺病变,其中良性病变组31例,恶性病变组41例,测量病变区ADC值及其周围正常腺体ADC值,并计算rADC(病变ADC值/周围正常腺体ADC值),将良性病变组ADC值和恶性病变组ADC值;良性病变组rADC和恶性病变组rADC分别做独立样本t检验,比较组间差异,并绘制ROC曲线。结果良性病变组ADC(1.33±0.24)×10^-3 mm²/s,恶性病变组ADC(0.94±0.25)×10^-3 mm²/s(t=-6.755,P<0.001);良性病变组rADC 0.71±0.12,恶性病变组rADC 0.50±0.12,(t=-7.389,P<0.001)。ADC值最佳诊断分界点为1.264×10^-3 mm²/s,ROC曲线下面积为0.856,灵敏度为80.5%,特异度为80.7%,rADC最佳诊断分界点为0.624,ROC曲线下面积为0.893,灵敏度为85.4%,特异度为90.3%。结论ADC值、rADC可以鉴别乳腺良恶性病变,rADC的诊断准确性更高。     

磁共振多参数定量分析在区分卵巢-附件O-RADS MRI 4分病变良恶性的价值

目的：评价磁共振多参数定量分析对区分卵巢-附件磁共振成像报告和数据系统(O-RADS MRI)4分病变良性和恶性的价值。方法：回顾性分析41例(44个)O-RADS MRI评分为4分的病灶，测量表观弥散系数(ADC)值、T2WI信号强度比值、T1WI增强强化率及信号强度值相应标准差。根据单因素分析结果确定最佳定量参数，采用受试者工作特征(ROC)曲线分析及约登指数确定最优参数阈值并组合为不同诊断模型，计算相应诊断效能。结果：入组44个病灶中26个(59.1%)为恶性。恶性组T2WI信号强度值标准差[11.2 (5.1,23.25) vs 58.95 (32.3,78.58),P=0.001]、最低信号区ADC平均值[1.16 (1.0,1.5)×10^-3mm²/s vs 1.79(1.31,2.21)×10^-3 mm²/s,P=0.001]及最小值[(1.11±0.38)×10^-3 mm²/s vs(1.63±0.51)×10^-3 m...     

磁共振扩散加权成像早期预测肺癌化疗疗效的价值

目的：评价磁共振扩散加权成像（DWI）对肺癌化疗疗效的早期预测价值。方法：对30例经病理证实的肺癌患者,在化疗前及第一周期化疗后进行MRI检查,包括常规T1wI,T2 wI及DWI检查。根据第二周期化疗后肿瘤最大径退缩率,按RECIST标准将患者分为治疗有效组和无效组,比较两组中肿瘤的表观扩散系数（ADC值）和最大径的差异,分析ADC值变化率的受试者工作特征曲线（ROc）,获得预测治疗有效的ADC值变化率临界值（cut—offvalue）。结果：第一周期化疗后,有效组化疗前后病灶的平均ADC值的差异有统计学意义（P值d0．001）;有效组和无效组中肿瘤ADC值的差异有统计学意义（P-0．031）;肿瘤最大径在两组间的差异无统计学意义（P-0．210）。以ADC值升高8．5％作为ADC值变化率诊断分界点,预测治疗获得PR的敏感度为85．7％,特异度为72．9％。结论：ADC值可以对肺癌化疗疗效进行早期监测。     

磁共振弥散加权成像预测出血性转化实验研究

目的:探讨3.0T磁共振弥散加权成像（DWI）中表观弥散系数（ADC）值及指数表观弥散系数（e ADC）值对兔急性脑缺血性脑卒中出血性转化（HT）的预测价值。方法:37只新西兰大白兔颈内动脉注射自体血栓制备急性脑缺血性脑卒中模型,模型制备3.5h时行DWI检查,模型制备成功者,术后4h行尿激酶静脉溶栓。模型成功72h后处死动物,行HE染色。应用SPSS16.0统计学软件,采用独立样本t检验比较无HT组与HT组之间ADC值、e ADC值的差异有无统计学意义。结果:27只新西兰大白兔急性缺血性脑卒中模型制作成功,其中6例发展为HT,HI型5例,PH型1例。无HT组3.5h梗死区ADC值为（0.752±0.114）×10-3mm²/s,HT组ADC值为（0.482±0.068）×10^-3mm²/s,两组ADC值的差异有统计学意义（P=0.000）。无HT组3.5h梗死区e ADC值为0.479±0.053,HT组e ADC值为0.618±0.074,两组e ADC值的差异有统计学意义（P=0.000）。结论:缺血性脑卒中急性期ADC值、e ADC值的改变与HT的发生存在一定相关性,ADC值越低、eADC值越高则HT发生的可能性就越大,这对临床溶栓治疗的预后判断有一定的参考意义。     

IVIM-DWI对TACE序贯氩氦刀治疗肝癌疗效的评估价值

目的：探讨基于体素内不相干运动（IVIM）双指数模型肝脏多b值DWI扫描对TACE序贯氩氦刀冷冻治疗肝癌后肿瘤活性的评估价值。方法：随机选取符合纳入标准的肝癌患者40例作为研究对象，先行TACE治疗；并于TACE术后4周内行氩氦刀冷冻消融治疗。所有患者于氩氦刀冷冻消融治疗后1~4个月行肝脏IVIM-DWI、MRI多期动态增强扫描及CT增强扫描。由3位副高以上职称专家单独阅片，根据影像学表现将治疗后病灶分为坏死灶、残留灶、新发灶。临床通过病理学检查或长期随访确定坏死灶、残留灶、新发灶，通过影像学与临床判断对比，比较双指数IVIM模型DWI与单指数DWI、CT平扫加增强扫描对病灶性质的评估价值，以及扫描对肝癌TACE序贯氩氦刀治疗后活性评估的敏感度、特异度。结果：CT平扫加增强扫描、MRI平扫加增强扫描在肝癌TACE序贯氩氦刀治疗后病灶性质判断方面差异无统计学意义（P=0.076），但DWI与CT平扫加增强扫描在判断病灶性质方面差异有统计学意义（P=0.000）。肝癌介入治疗后坏死灶、残留灶、新发灶的ADC、Slow ADC及f值差异均有统计学意义（均P<0.05）；残留灶与新发灶的ADC、Slow ADC值明显低于坏死灶（均P<0.01）。DWI对TACE序贯氩氦刀治疗肝癌后活性评估，当界值ADC=1.29×10^-3 mm²/s时，对肝癌活性诊断的敏感度及特异度分别达77.0%、90.8%；IVIM模型DWI当界值Slow ADC=1.18×10^-3 mm²/s时，对肝癌活性诊断的敏感度及特异度分别达82.5%、95.9%；CT增强扫描当CT净增值界值取14.40 HU时，对肝癌活性诊断的敏感度及特异度分别达75.0%、85.7%。结论：IVIM-DWI可对肝癌TACE序贯氩氦刀治疗后活性情况进行有效评估，且其评估肝癌TACE序贯氩氦刀治疗疗效价值明显优于单指数模型DWI及CT增强扫描。     

探讨DWI对肺癌靶向治疗疗效监测的最佳时间点

目的 探讨DWI非小细胞肺癌(NSCLC)靶向治疗疗效早期监测的最佳时间点。方法 选取62例经病理确诊的NSCLC患者，对肿瘤首次靶向治疗前1周内、靶向治疗后1周、3周(第1疗程)、6周(第2疗程)行胸部MRI扫描，在第2疗程治疗结束后根据实体瘤疗效评价标准分为有效组与无效组，对比两组患者在治疗前1周内及治疗后1周、3、6周4个时间点的表观扩散系数(ADC)值及其变化。结果 有效组治疗后1周及3周的ADC值较治疗前明显升高(P>0.05);无效组治疗前后ADC值无明显差异。有效组治疗后3周的ADC值明显高于无效组(P>0.05)。ROC分析治疗后1周及3周ADC值变化的曲线下面积分别为0.756、0.870(z=2.032,P=0.042)。肿瘤缩小与肿瘤靶向治疗前ADC值呈负相关(r=-0.418),与治疗后1周和3周ADC值的增加呈正相关(r=0.30、0.501)。结论 以靶向治疗第1疗程结束时作为监测时间点，DWI可以对NSCLC的靶向治疗疗效做出较为准确的早期评估。     

磁共振弥散加权成像在125Ⅰ粒子组织间植入治疗胰腺癌疗效评估中的应用

目的探讨磁共振（MRI）弥散加权（DWI）成像对¹²⁵Ⅰ粒子组织间植入治疗人胰腺癌裸鼠移植瘤疗效的评估价值。方法将人胰腺癌SWI990细胞株接种于BABL/C裸鼠右下肢旁腹股沟区偏背侧皮下,待瘤体长至8～10 mm进行干预,共有16只裸鼠的成瘤大小适用于实验,分为实验组8只,植入¹²⁵Ⅰ粒子,和对照组8只,植入空载粒子。粒子植入前及治疗后2周和2个月时分别行MRI常规扫描及DWI成像。取瘤体标本行组织病理学检查。结果实验组肿瘤细胞坏死明显,而对照组肿瘤细胞无明显或有少许坏死。裸鼠心、肝、肺、肾及脾脏等组织无明显放射炎症表现。常规MRI成像评价¹²⁵Ⅰ粒子治疗胰腺癌疗效的价值有限。DWI显示实验组内整个肿瘤组织的表观弥散系数（ADC）值在治疗前为（0.001 15±0.000 13）mm²/s,治疗后2周为（0.00I 29±0.000 038）mm²/s,治疗后2个月为（0.002 08±0.000 14）mm²/s,与治疗前相比差异有统计学意义（P<0.05）。实验组肿瘤实质区的ADC值亦较治疗前及对照组增高,但低于坏死区ADC值。结论 ¹²⁵Ⅰ粒子组织间植入治疗人胰腺癌裸鼠移植瘤可导致肿瘤坏死.并对周围脏器是安全的。用常规MRI及DWI成像观察裸鼠皮下移植瘤可行。DWI对疗效评估有重要价值。     

Report of diffusion-weighted MRI in two cases with different cerebral hydatid disease

Purpose: To present MRI findings in two cases of cerebral hydatid disease with an emphasis on diffusion-weighted imaging (DWI) findings of Echinococcus granulosus (EG) versus Echinococcus alveolaris (EA).

Results: EG lesions were isointense with cerebrospinal fluid in all sequences including DWI. On DWI, EA lesions remained hypointense on b=1000 s/mm² diffusion-weighted images. Apparent diffusion coefficient (ADC) values of EG and EA lesions were completely different from each other, 2.88±0.24×10^-3 s/mm² and 1.33±0.15×10^-3 s/mm², respectively.

Conclusion: The ADC values could not be used to discriminate from other differential diagnoses.     

联合DWI和常规MRI征象在睾丸生殖细胞瘤中的诊断价值

目的:探讨DWI联合常规MRI征象对睾丸精原细胞瘤与非精原细胞瘤(NSGCT)的鉴别诊断价值.方法:搜集经病理证实的睾丸生殖细胞瘤患者46例,其中精原细胞瘤28例,非精原细胞瘤18例,46例患者均行MRI平扫及DWI扫描.两位医师采用双盲法行常规MRI征象观察及ADC值测量,并比较上述指标在睾丸精原细胞瘤与非精原细胞瘤...     

Diffusion-weighted magnetic resonance imaging allows monitoring of anticancer treatment effects in patients with soft-tissue sarcomas

PURPOSE: To determine if diffusion-weighted imaging (DWI) can be used as a surrogate marker of tumor response to anticancer therapy in patients with soft-tissue sarcomas. MATERIALS AND METHODS: Magnetic resonance imaging (MRI) including echo-planar DWI sequences was performed prospectively in 23 consecutive patients with soft-tissue sarcomas before and after initiation of regional or systemic chemotherapy. The mean interval between initial and follow-up MRI was 56.9 +/- 23.2 days. Tumor volumes were determined by manual segmentation of tumor borders on contrast-enhanced T1-weighted images. The apparent diffusion coefficient (ADC) was calculated from corresponding sections of ADC maps on initial and follow-up DWI. Subsequently, changes in tumor volumes and ADC were correlated using the Pearson correlation coefficient. RESULTS: A high degree of correlation was found when changes in tumor volumes and ADC values were compared (r = -0.925, P < 0.0001), regardless of the effectiveness of anticancer therapy expressed as changes of tumor volume. CONCLUSION: DWI can be used as a supplement to morphologic imaging for the evaluation of tumor response to anticancer therapy in patients with soft-tissue sarcomas. As cellular changes are expected to precede morphologic changes in treated tumors, DWI performed at an early stage of fractionated therapy may provide unique prognostic information of its effectiveness.     

Diffusion-weighted magnetic resonance imaging of treatment-associated changes in recurrent and residual medulloblastoma: preliminary observations in three children

Purpose: To emphasize a possible role of magnetic resonance (MR) diffusion-weighted imaging (DWI) for lesion conspicuity and detection of treatment effects in children with medulloblastoma.

Material and Methods: Three children with medulloblastoma (two residual and one recurrent) were examined repetitively by MR diffusion-weighted imaging. Regional assessment of the apparent diffusion coefficient (ADC) was done for tumorous lesions and periventricular white matter appearing normal on standard MR images.

Results: All lesions were clearly visible on DWI. In the case of recurrent tumor, on one scan, DWI showed lesions that were not seen on contrast-enhanced MRI. Increase (41%) of ADC was seen in one lesion, which subsequently responded completely to treatment over 27 months' follow-up. Intermediate increases (23-26%) of ADC were found with partial therapy response in three lesions. In contrast, a decrease (-11%) of ADC in two lesions was seen with tumor progression.

Conclusion: These observations may suggest a role for DWI in early detection of metastatic disease and treatment monitoring of medulloblastoma, warranting a formal study.     

Quantitative study of prostate cancer using three dimensional fiber tractography

AIM:To investigate feasibility of a quantitative study of prostate cancer using three dimensional（3D）fiber tractography.METHODS:In this institutional review board approved retrospective study,24 men with biopsy proven prostate cancer underwent prostate magnetic resonance imaging（MRI）with an endorectal coil on a 1.5 T MRI scanner.Single shot echo-planar diffusion weighted images were acquired with b = 0.600 s/mm²,six gradient directions.Open-source available software Track Vis and its Diffusion Toolkit were used to generate diffusion tensor imaging（DTI）map and 3D fiber tracts.Multiple 3D spherical regions of interest were drawn over the areas of tumor and healthy prostatic parenchyma to measure tract density,apparent diffusion coefficient（ADC）and fractional anisotropy（FA）,which were statistically analyzed.RESULTS:DTI tractography showed rich fiber tract anatomy with tract heterogeneity.Mean tumor region and normal parenchymal tract densities were 2.53 and 3.37 respectively（P < 0.001）.In the tumor,mean ADC was 0.0011 × 10^-3 mm²/s vs 0.0014 × 10^-3 mm²/s in the normal parenchyma（P < 0.001）.The FA values for tumor and normal parenchyma were 0.2047 and 0.2259 respectively（P = 0.3819）.CONCLUSION:DTI tractography of the prostate is feasible and depicts congregate fibers within the gland.Tract density may offer new biomarker to distinguish tumor from normal tissue.     

Echo-planar and gradient-echo diffusion MRI of normal brain iron in the globus pallidus

The purpose of this study was to investigate effects of normal brain iron on proton diffusion and its quantification by diffusion MRI. The studies were undertaken in 24 cases ages ranging from 15 to 74 years (mean=45 years) with normal iron deposition in the globus pallidus to characterize the appearances on diffusion imaging with differing b values and on apparent diffusion coefficient (ADC) maps. Diffusion MRI was obtained by the spin-echo echo-planar imaging sequence (n=20 patients) or by the gradient-echo diffusion sequence, PSIF (n=4). In the PSIF sequence, pixel lens calculations were performed. In the echo-planar sequence, ADC value calculations were performed by using Stejskal–Tanner formula and by direct reading from automatically generated ADC maps. ADC values obtained from the normal appearing parenchyma were used as controls. Twenty patients with acute cerebral infarction were included for comparison of ADC values with those of iron deposition. The mean ADC value in the normal cerebral parenchyma was 0.85±0.11×10⁻³ mm²/s. In the globus pallidus, mean ADC value was 48±0.12×10⁻³ mm²/s. That of regions with acute infarction was 0.34±0.11×10⁻³ mm²/s. On b=0 or 50, b=500 and b=1000 s/mm² images of the echo-planar diffusion imaging globus pallidus appeared hypointense compared to surrounding parenchymal structures. Low signal and low pixel values were evident on the PSIF imaging. This study indicates that, on diffusion MRI, normal iron deposition reveals prominent low signal on all the images of the echo-planar diffusion imaging sequence with differing b values, as well as on the gradient-echo diffusion, PSIF sequence. Low signal on ADC maps and low ADC values are evident. These represent characteristic diffusion MRI features of normal iron deposition in the brain, reflecting susceptibility effects.     

Value of apparent diffusion coefficient calculation in the differential diagnosis of parotid gland tumors

Background: The differential diagnosis of parotid gland tumors is often difficult with conventional magnetic resonance imaging.

Purpose: To determine whether the calculation of the apparent diffusion coefficient (ADC) is valuable for making the differential diagnosis of parotid tumors.

Material and Methods: Thirty parotid masses in 28 patients and 24 healthy parotid glands in 12 controls were examined in this prospective study. Diffusion-weighted magnetic resonance imaging with echo-planar spin-echo sequences was used to evaluate each subject. The ADC of each tumor and each healthy parotid gland was calculated. Tumor diagnoses were confirmed by the results of histopathologic analysis.

Results: The following types of masses were identified: 11 Warthin tumors, nine pleomorphic adenomas, seven malignant tumors, one basal cell adenoma, and two benign cysts. The mean ADC value for the Warthin tumors was 0.97±0.16×10^-3 mm²/s, for the pleomorphic adenomas was 1.74±0.37×10^-3 mm²/s, for the malignant tumors was 1.04±0.35×10^-3 mm²/s, and for the normal parotid glands was 0.34±0.20×10^-3 mm²/s. The respective ADC value for the single basal cell adenoma was 1.40×10^-3 mm²/s. Statistically significant differences were identified between the subjects with pleomorphic adenoma and those with another type of parotid tumor, and between subjects with healthy parotid glands and those with a tumor.

Conclusion: Calculating the ADC appears to be useful in differentiating pleomorphic adenomas from other types of parotid gland tumors.