磁共振弥散加权成像在诊断膀胱肿瘤恶性程度中的价值

目的:探讨磁共振弥散加权成像(diffusion weighted imaging,DWI)对膀胱肿瘤的诊断价值。方法:对36例膀胱肿瘤患者进行常规膀胱磁共振平扫检查及DWI检查,选取病灶感兴趣区测出膀胱肿瘤病灶区域大小,拟合出表观扩散系数(ADC)图,并在ADC图上直接测量不同b值(b=1 200、1 500s/mm2)及其膀胱肿瘤病灶的平均ADC值,进行量化分析。随后患者在1周内行经尿道膀胱肿瘤电切术,部分患者行根治性膀胱切除术,术中切除组织送病理检查。结果:36例患者中,b值为1 500、1 200s/mm2。在同一b值下,膀胱恶性肿瘤组的平均ADC值低于良性肿瘤组,分别为748.12±93.60、1 190.88±86.47,803.40±103.91、1 266.93±89.15(P0.05);膀胱高级别乳头状尿路上皮癌组的平均ADC值明显低于低级别乳头状尿路上皮癌组,分别为651.15±24.82、817.39±51.71,699.54±24.13、877.57±24.13(P0.05)。结论:DWI及ADC值在诊断膀胱肿瘤恶性程度中具有一定的价值。     

MRI增强扫描及DWI扫描在肝脏良恶性肿瘤鉴别诊断中的应用

目的探讨腹部磁共振成像(MRI)增强扫描及弥散加权成像(DWI)技术在行手术治疗肝脏肿瘤患者良恶性鉴别诊断中的应用。方法研究纳入2018年1月至2021年6月行手术治疗肝脏结节患者共160例，均行腹部MRI增强扫描及DWI扫描检查，根据肿瘤类型分组，分析各类病灶DWI序列下表观弥散系数(ADC)值，比较腹部MRI增强扫描及DWI扫描单用或联用诊断肝脏良恶性肿瘤符合率。结果在弥散敏感系数(b)值分别设置为50 s/mm³、400 s/mm³及800 s/mm³条件下，肝细胞癌及肝转移癌病灶ADC值均显著低于肝血管瘤、肝囊肿(P<0.05);b值设置为800 s/mm³条件下肝脏良恶性病灶ADC值均显著低于50 s/mm³、400 s/mm³(P<0.05)；同时b值设置为400 s/mm³条件下肝脏良恶性病灶ADC值均显著低于50 s/mm³(P<0.05)；腹部MRI增强扫描联合DWI扫描用于肝...     

3.0T磁共振扩散加权成像诊断肾血管 平滑肌脂肪瘤

目的探讨MR扩散加权成像（DWI）及相应的表观扩散系数（ADC）对肾血管平滑肌脂肪瘤（AML）的诊断价值。方法收集经手术病理证实的肾脏AML患者15例,其中典型AML 10例,不典型AML 5例;正常对照组15名,对病变区域行DWI及常规MRI,测量b=50～1000 s/mm^2时肾脏AML及正常对照组的ADC值。结果肾脏典型AML、不典型AML及正常对照组的ADC值（×10^-3mm^2/s）分别为（0.87±0.08）、（1.55±0.34）、（1.82±0.18）,差异有统计学意义（P〈0.05）。结论3.0T磁共振DWI及ADC值测定可为诊断肾脏AML提供帮助。     

高弥散敏感因子(b)值DWI 及ADC 值对前列腺癌与前列腺炎鉴别诊断的应用对比分析

目的:探讨高弥散敏感因子(b)值扩散加权成像(DWI)及表面扩散系数(ADC)在前列腺癌和前列腺炎鉴别诊断的应用价值。方法:回顾性分析2018年4月—2019年9月经手术、活检病理或随访证实最终诊断的前列腺癌21例(25个病灶)和前列腺炎20例(28个病灶)。所有患者于手术或穿刺前行MRI扩散加权成像,b值选择1000、2000、3000 s/mm^2,观察不同b值的DWI及ADC值对前列腺癌和前列腺炎的定性诊断准确率。比较不同b值的DWI及ADC值在前列腺癌和前列腺炎病变诊断中有无统计学意义,分别计算出不同的b值DWI诊断前列腺癌和前列腺炎的诊断效能。结果:b值选择为1000、2000、3000 s/mm^2 DWI在前列腺癌和前列腺炎病变鉴别诊断中均有统计学意义(P<0.05),b值选择1000、2000、3000 s/mm^2在DWI诊断前列腺癌和前列腺炎的特异性、准确度分别为71.4%、84.9%,92.9%、92.5%,100.0%、96.2%,b值选择2000、3000 s/mm^2 DWI诊断前列腺癌和前列腺炎的特异性、准确度高于b值选择1000 s/mm^2 DWI。b值选择为1000、2000、3000 s/mm^2时,前列腺癌的ADC值均低于前列腺炎,并且b值选择为1000、2000、3000 s/mm^2所测得的ADC值前列腺癌和前列腺炎组间差异有统计学意义(P<0.05)。结论:采用高b值DWI及ADC值可以准确区分前列腺癌和前列腺炎,具有良好的定性诊断价值。     

DKI及DWI对乳腺疾病良恶性诊断的效能分析

目的探讨磁共振弥散峰度成像(DKI)及弥散加权成像(DWI)对乳腺疾病良恶性诊断的效能分析。方法选取2019年12月至2020年12月期间本院收治60名乳腺出现占位性病变患者进行研究。所有患者入院后均进行常规MR检查及DKI及DWI扫描,分析患者DWI测定表观弥散系数(ADC)、DKI测定的平均峰度(MK)、平均弥散系数(MD)值,评估患者病灶良性或恶性等情况,并采用受试者工作特征曲线(ROC曲线)评价诊断效能。结果良性病变患者ADC、MD值明显高于恶性病变患者,MK值明显低于恶性病变患者(P0.05);恶性病变患者,MD的曲线下面积(AUC)明显高于ADC的AUC(P0.05);MK的AUC与ADC的AUC相比(P0.05);联合MD、MK对恶性病灶的AUC明显高于ADC的AUC(P0.05)。结论 DKI对乳腺疾病良恶性的诊断效能明显优于DWI,值得推广应用。     

MR弥散加权成像对泡型肝包虫病的评估价值研究

目的分析泡型肝包虫病的磁共振(MR)弥散加权成像(DWI)的特征,评估表观弥散系数(ADC)在泡型肝包虫病中的潜在应用价值。方法回顾性分析2013年11月至2015年1月期间青海大学附属医院根据流行病学、实验室检验和影像学检查及外科手术确诊为泡型肝包虫病的26例患者的临床资料,行3.0 T MR肝脏平扫,DWI序列的b值分别为0、600、1 000、1 200 s/mm~2。所有数据储存至PACS系统,经两名副主任医师参与评定病灶的分型、大小、分布、位置、钙化(CT检查)特征,测量不同b值下包虫中心区、边缘区、周边区肝实质的ADC值并进行比较。结果 1 26例患者共有29个病灶,多累及多个肝段,21个(72%)病灶分布于右半肝,同时累及左、右叶者有4个。24个病灶侵犯肝静脉或门静脉,20个病灶侵犯肝内胆管,10个病灶侵犯右侧肾上腺。7例患者出现肝门区、腹膜后多发增大淋巴结,5例患者出现肺转移,3例患者出现脑转移,同时有肺转移及脑转移患者3例。2液化坏死性病灶20个,其中5个病灶的T2WI边缘有多发小囊,15个病灶的T2WI边缘均为实性成分并未见小囊;12个病灶的中心区DWI呈明显高信号,8个病灶的中心区DWI呈低信号。实性病灶9个,其中有2个病灶的边缘T2WI有小囊,有7个病灶的T2WI为实性成分;实性病灶的DWI为均匀一致的低信号,边缘有均匀少量较连续或不连续环形高信号。3在同一b值下,液化坏死性病灶中心区的ADC值均明显高于实性病灶(P0.01)。在液化坏死性病灶内不同b值下,周边区的ADC值均明显低于边缘区(P0.01)和中心区(P0.05);在实性病灶内不同b值下,周边区和边缘区的ADC值均明显低于中心区(P0.05)。结论 MR的DWI能清晰分辨泡型肝包虫的结构及成分,对区别肝脏其他疾病有较高的价值。液化坏死性病灶中心区的平均ADC值明显高于实性病灶中心区的ADC值。     

静脉注射Gd-DTPA肝脏局灶性病变弥散加权成像的定量对照研究

目的:探讨静脉注射Gd-DTPA前后肝脏局灶性病变(FLLs)弥散加权成像(DWI)的信噪比(SNR)、对比噪声比(CNR)及表观弥散系数(ADC)值的变化。方法:26例26个病灶中,肝脏海绵状血管瘤6个,肝细胞癌20个。所有病灶静脉注射Gd-DTPA前后分别进行DWI检查,b值600s/mm2。病灶的SNR、CNR在DWI测量及计算得出,ADC值的测量在ADC图完成。结果:静脉注射Gd-DTPA后病灶的SNR、CNR均增大,前后差异均有统计学意义(P=0.036,P=0.008)。病灶的ADC值减小,前后差异有统计学意义(P=0.019)。结论:尽管静脉注射Gd-DTPA后FLLs的DWI图像质量有所提高,但是FLLs的ADC值显著减小,从ADC值定量研究考虑,DWI应在注射Gd-DTPA前进行。     

超声造影对肾脏占位病变的诊断意义

目的评价超声造影对彩色多普勒超声诊断肾肿瘤的临床意义。方法应用彩超检查２７个（２６例）肾脏占位病变,观察超声造影前后病变内血流显示情况。结果超声造影后：（１）肾癌病灶内血流信号明显增强,显著增强者占７２％;（２）肾错构瘤７５％无增强,肾囊肿均无增强;（３）肾柱肥大增强与肾实质一致。造影前后诊断敏感性分别为７４％与１００％。结论超声造影有助彩超更准确评价肾肿瘤血供状况,对肾占位病变诊断与鉴别有重要临床意义。     

螺旋CT扫描在乏脂肪肾错构瘤、小肾癌的鉴别诊断中的应用价值研究

目的 探讨螺旋CT在鉴别诊断乏脂肪肾错构瘤和小肾癌的应用价值.方法 收集2011年1月至2014年12月在本院治疗的肾脏小肿瘤患者临床和影像资料,其中小肾癌患者42例,乏脂肪肾错构瘤23例,分析各患者螺旋CT扫描表现,测量肿瘤感兴趣点(ROI) CT值,评价肿瘤平扫密度、强化程度等.结果 小肾癌平扫期ROI CT值为(33.24±10.24) Hu,明显高于乏脂肪肾错构瘤的(9.87±2.87)Hu,差异有统计学意义(P＜0.05);小肾癌和乏脂肪肾错构瘤皮质期、实质期ROI CT值差异比较无统计学意义(P＞0.05);小肾瘤和乏脂肪肾错构瘤CT影像表现在是否存在钙化、强化是否均匀、肿瘤边缘是否整齐光滑中,比较差异无统计学意义(P＞0.05);是否存在假包膜、肿瘤的强化形式在小肾瘤和乏脂肪肾错构瘤CT影像表现比较时差异有统计学意义(P＜0.05);平扫期ROI CT值ROC曲线下面积为0.970,P＜0.05,当以平扫期ROI CT值≤16.19Hu诊断乏脂肪肾错构瘤时,诊断的灵敏度为90.50％,特异度为100.00％.结论 螺旋CT在鉴别诊断乏脂肪肾错构瘤和小肾癌有重要价值,肿瘤的平扫密度、强化形式等是鉴别诊断中有价值的CT表现特点,测量平扫期ROI CT值对鉴别诊断有比较高的价值.     

磁共振DWI及动态增强对前列腺癌的诊断

目的 探讨磁共振弥散加权成像及动态增强在前列腺癌诊断中的价值.方法 分别对24例前列腺癌（PCa）患者、30例前列腺增生（BPH）患者行前列腺DWI及动态增强扫描,15名健康志愿者进行前列腺DWI扫描.分析3组DWI图、ADC图的信号表现,测量ADC值,比较PCa组及BPH组动态增强曲线.所有PCa病例、BPH病例均经手术或穿刺活检病理证实.结果 DWI上PCa表现为高信号影,BPH呈混杂信号,志愿者外周带呈稍高信号.PCa癌灶平均ADC值0.98×10-3mm2/s,增生结节平均ADC值1.46×10-3mm2/s,志愿者前列腺外周带平均ADC值1.85×10-3mm2/s,三者之间的差异互有统计学意义（P＜0.05）.动态增强PCa主要表现为早期强化,BPH主要表现为逐渐强化,PCa与BPH的时间-信号强度曲线类型差异有统计学意义（P＜0.05）.结论 在DWI图像上,PCa癌灶信号较高.PCa癌灶的ADC值低于正常前列腺外周带及前列腺增生.动态增强时PCa癌灶以早期强化为主.这二者均可作为前列腺癌的诊断依据.     

Congestive myelopathy due to cervical perimedullary arteriovenous fistula evaluated by apparent diffusion coefficient values - case report

A 22-year-old woman presented with a cervical perimedullary arteriovenous fistula (AVF) manifesting as right upper and lower extremity weakness. T2-weighted magnetic resonance (MR) imaging showed intramedullary hyperintensity believed to be caused by venous congestion. Preoperative diffusion-weighted MR imaging showed increased apparent diffusion coefficient (ADC) value. Spinal angiography demonstrated an AVF fed mainly by the right C-5 radicular artery. Complete obliteration of AVF was achieved by endovascular embolization and microsurgical shunt occlusion. The ADC value was normalized and her neurological deficits improved after endovascular surgery, whereas T2-weighted MR imaging still demonstrated the lesion. The high preoperative ADC value probably indicated reversible vasogenic edema and immediate normalization of the ADC value suggests a good clinical outcome.     

Prediction of tissue survival after middle cerebral artery occlusion based on changes in the apparent diffusion of water

OBJECT: In this study the authors tested the hypothesis that the estimate of the apparent diffusion coefficient (ADC) of water is a reliable pathophysiological index of the viability of ischemic brain tissue. METHODS: Cerebral blood flow (CBF) and the cerebral metabolic rates of oxygen and glucose (CMRO2 and CMRglc, respectively) were measured using positron emission tomography (PET) scanning before and after permanent middle cerebral artery occlusion (MCAO) or reperfusion in pigs. The ADC value, which was measured using diffusion-weighted magnetic resonance (DW MR) imaging was compared with physiological variables obtained by PET scanning and with histological findings. After both permanent MCAO and reperfusion, the decrease in the ADC was significantly correlated with decrease in the CMRO2 and CMRglc. The infarction coincided with a CMRO2 threshold of 50% of the value measured on the contralateral side. Thus, an ADC value of 80% or 75% of the contralateral value reflected the CMRO2 threshold after permanent MCAO or reperfusion, respectively. On DW MR images, lesions with ADC values above 80% of the contralateral value are potentially reversible until 6 hours after MCAO, whereas lesions with ADC values below 75% of the contralateral value are irreversible as early as 2 hours after MCAO. CONCLUSIONS: The ADC of water provides a reliable pathophysiological index for tailoring therapy to the condition of individual stroke patients in clinical practice.     

Diffusion-weighted imaging of traumatic subdural hematoma in the subacute stage

Five cases of traumatic subdural hematomas in the subacute stage (from 7 to 20 days after head injury) were treated in one male and four females, aged from 63 to 82 years, with evacuation via craniotomy in three and aspiration via burr hole surgery in two. All hematomas were evaluated by T1-, T2-, and diffusion-weighted magnetic resonance imaging, and measurement of the apparent diffusion coefficient (ADC). Diffusion-weighted imaging showed the hematoma as a crescent high intensity area with a low intensity rim close to the brain surface (two-layered structure) in four cases and as high intensity with low intensity components in one case. The high intensity areas under the dura mater on diffusion-weighted imaging appeared as homogeneous high intensity on T1- and T2-weighted imaging in four cases, and inhomogeneous high intensity on T1- and isointensity on T2-weighted imaging in one case. The mean ADC value of the high intensity areas was 0.58 +/- 0.23 (mean +/- standard deviation) x 10(-3) mm2/sec. The operative findings revealed the high intensity areas as solid clots. The low intensity areas on diffusion-weighted imaging appeared as homogeneous high intensity in four cases and inhomogeneous isointensity with high intensity components in one case on T1- and T2-weighted imaging. The mean ADC value of the low intensity areas was 2.03 +/- 0.27 x 10(-3) mm2/sec. The operative findings revealed the low intensity areas as mixtures of resolved clot and cerebrospinal fluid. Diffusion-weighted imaging showed the characteristic two-layered structure in traumatic subdural hematomas in the subacute stage, and analysis of the ADC values was useful for differentiating solid from liquid hematoma and for selection of the surgical procedure.     

Efficacy of diffusion-weighted magnetic resonance imaging in detecting infected cysts in a case of polycystic kidney disease

Hepatic and/or renal cyst infection is a major complication in patients with polycystic kidney disease. In many cases, drainage of infected cysts is necessary, although accurate detection of infected cysts from among the numerous hepatic or renal cysts present is often difficult, because the findings of infected cysts on computed tomography and T1- and T2-weighted magnetic resonance imaging resemble those of normal cysts. We describe here a case of polycystic kidney disease complicated by hepatic cyst infection. On diffusion-weighted magnetic resonance imaging (DWMRI), which is occasionally used in the diagnosis of cerebral abscesses, infected hepatic cysts showed higher signal intensity than other cysts, facilitating differentiation of the cysts requiring drainage from numerous other cysts. Infected cysts showed a marked decrease of the apparent diffusion coefficient (ADC) values compared with those of normal cysts. DWMRI was very effective in detecting infected cysts in our patient and may be of value in other such cases with polycystic kidney disease.     

Non-convulsive status epilepticus and consciousness disturbance after star fruit (Averrhoa carambola) ingestion in a dialysis patient

Star fruit ingestion may induce severe neurological complications in chronic renal failure patients. We present a case on maintenance dialysis therapy who developed a consciousness disturbance without convulsion after eating star fruit. The symptoms became aggravated after haemodialysis. The brain computed tomography scan showed no abnormal findings, but the electroencephalogram found active focal sharp waves in the left central regions and diffusion-weighted magnetic resonance imaging also showed hyperintense lesions in the left central regions that were compatible with non-convulsive status epilepticus. His condition improved dramatically after anticonvulsant therapy and regular haemodialysis. The patient was discharged 20 days later without neurological sequela.     

Contemporary imaging of the renal mass

Contemporary imaging techniques for renal mass evaluation are essential to clinical management and surgical planning. Ultrasonography can be used to distinguish cystic from solid lesions but is less sensitive and accurate in renal mass characterization than computed tomography (CT) and magnetic resonance imaging (MRI). Multiphase CT imaging before and after administration of contrast is the primary imaging modality for characterization and staging of renal lesions. MRI is increasingly used as a problem solving tool. Advanced MRI techniques such as diffusion-weighted imaging and perfusion-weighted imaging are being explored in assessment of renal lesions. These techniques are discussed in this article.     

Subdural hyperintense band on diffusion-weighted imaging of chronic subdural hematoma indicates bleeding from the outer membrane

The diffusion-weighted magnetic resonance (MR) imaging characteristics of chronic subdural hematoma and the correlation between hematoma liquidity and apparent diffusion coefficient (ADC) were investigated in 26 consecutive patients, 16 males and 10 females aged 42 to 92 years (mean +/- SD 73.3 +/- 13.1 years), with 31 chronic subdural hematomas. The chronic subdural hematomas were divided into homogeneous, separate, and trabecular types based on diffusion-weighted MR imaging findings. Almost all hematomas were low intensity on diffusion-weighted imaging, and the mean ADC value was 1.81 +/- 0.79 x 10(-3) mm2/sec. The high intensity areas in the subdural hematomas consisted of several types: high intensity line along the dura mater (subdural hyperintense band), high intensity along the intrahematoma septum, and laminar shape along the inner membrane. The subdural hyperintense bands accounted for almost all high intensity areas in the subdural hematomas. The mean ADC value of the high intensity areas was 0.76 +/- 0.24 x 10(-3) mm2/sec, close to that of the normal brain. The subdural hyperintense bands were considered to be intracellular and/or extracellular methemoglobin based on the T1- and T2-weighted imaging and intraoperative findings. The subdural hyperintense band is an important finding indicating relatively fresh bleeding from the outer membrane. Diffusion-weighted imaging shows liquid subdural hematoma as low intensity, and measurement of the ADC values can differentiate between liquid and solid components of the chronic subdural hematoma.     

Detection and characterization of the evolution of cerebral abscesses with diffusion-weighted magnetic resonance imaging--two case reports

A 57-year-old man and a 45-year-old woman presented with cerebral abscesses. Diffusion-weighted magnetic resonance (MR) imaging and conventional MR imaging clearly showed the different stages of the course of the brain abscesses. As the abscess matured, the signal intensity of the center gradually increased to the typical high value with a low apparent diffusion coefficient (ADC) on diffusion-weighted MR imaging, and enhancement of the capsule on T1-weighted MR imaging with gadolinium. Healing of the abscess was revealed by the signal intensity of the center returning to isointense and an increase in ADC to the baseline. Surrounding edema showed an increase in ADC, followed by a return to the baseline. These changes probably reflect the pathological processes occurring in the abscesses.     

磁共振成像扩散加权成像技术在鉴别原发性胆囊癌和肝细胞癌中的价值

目的 探讨MRI扩散加权成像(DWI)技术对侵犯肝脏的原发性胆囊癌和侵犯胆囊的原发性肝细胞癌进行鉴别诊断的价值.方法 回顾性分析2009年1月至2010年10月解放军总医院收治的11例原发性胆囊癌和19例原发性肝细胞癌患者的临床资料.采用MRI DWI技术对两种疾病进行鉴别诊断.选择扩散敏感梯度场参数(b值)为800 s/mm2时进行扫描,绘制受试者工作特征曲线(ROC),比较原发性肝细胞癌和原发性胆囊癌的表观弥散系数(ADC)阈值.利用独立样本t检验比较两组ADC值之间的差异.结果 30例患者共30个肿瘤,所有肿瘤在DWI图像上呈高信号,T1WI呈稍低信号,T2WI呈稍高信号,原发性胆囊癌累及肝脏的边界欠清楚.11例原发性胆囊癌患者的肿瘤主要位于胆囊窝区,其中10例累及肝脏,平均ADC值为(0.89±0.14)mm2/s;19例原发性肝细胞癌患者中,15例肿瘤位于肝右叶,4例肿瘤位于肝左叶,平均ADC值为(1.04±0.18)mm2/s,两者ADC值比较,差异有统计学意义(t=2.425,P＜0.05).ROC曲线下面积为0.756(95%CI:0.577～0.935),当阈值为0.96 mm2/s时,敏感性为68.4%,特异性为81.8%.结论 b值为800 s/mm2时,原发性胆囊癌的ADC值低于原发性肝细胞癌,有利于两种疾病的鉴别诊断.

Abstract：

Objective To investigate the value of diffusion-weighted magnetic resonance imaging in the differential diagnosis of primary gallbladder cancer with liver invasion and primary hepatocellular carcinoma (HCC) with gallbladder invasion. Methods From January 2009 to October 2010, 11 patients with primary gallbladder cancer and 19 patients with primary HCC were admitted to the PLA General Hospital. The clinical data of the 30 patients were retrospectively analyzed. All patients underwent diffusion-weighted magnetic resonance imaging with b value of 800 s/mm2, and the receiver operating curve (ROC) was drawn. The apparent diffusion coefficient (ADC) values of the patients with gallbladder cancer and HCC were compared by independent sample t test. Results Thirty tumors were detected in the 30 patients. All tumors showed high signal on DWI, slightly low signal on T1 WI and slightly high signal on T2 WI. The foci of 11 patients with primary gallbladder cancer were at the gallbladder fossa, and 10 of them had liver involvement. The mean ADC value of the 11 patients was (0.89 ±0. 14)mm2/s. Of the 19 patients with primary HCC, the foci of 15 patients were at the right lobe of liver, and 4were at the left lobe. The mean ADC value of the 19 patients was (1.04 ±0.18)mm2/s. There was a significant difference in the ADC value between patients with primary gallbladder cancer and those with primary HCC ( t =2.425, P＜0. 05). The area under the ROC was 0. 756 (95% confidence interval: 0.577-0. 935), and the sensitivity and specificity were 68.4% and 81.8%, respectively, when the threshold value was 0.96 mm2/s.Conclusion The ADC value of patients with primary gallbladder cancer is lower than those with primary HCC when the b value is 800 s/mm2, which is helpful in the differential diagnosis of primary gallbladder cancer and primary HCC.