3.0T磁共振DWI结合T2WI鉴别前列腺移行区的良恶性结节

目的 探讨分别应用T2WI、DWI以及综合应用2种成像序列对前列腺移行区良恶性结节的鉴别诊断价值.方法 收集2006-08-2010-04在本院3.0T磁共振行常规及DWI扫描(b值分别为0 s/mm2和800 s/mm2)的前列腺疾病患者,其中70例前列腺移行区见到结节样异常信号者被纳入本研究,本组患者后来均行超声引导下经直肠前列腺穿刺活检术.分析良恶性结节的MRI表现,比较其ADC值.采用5分制评分,将所得结果与病理结果对照,用SPSS11.5分别做受试者工作特征曲线(ROC),分析比较各组方法诊断的敏感度和特异度.结果 病理证实54例患者为前列腺移行区良性结节,16例为移行区前列腺癌(prostate cancer,PCa),良性和恶性结节的ADC值分别为(1.352±0.088 5)×10-3 mm2/s和(0.931±0.079 5)×10-3 mm2/s,恶性结节的ADC值明显低于良性结节(P<0.05).联合DWI和T2WI 2种成像序列鉴别前列腺移行区良恶性结节的ROC曲线下面积(AUC)最大(0.993,95%CI:0.935~0.995),其与单独应用T2WI 的AUC之间的差异有统计学意义(Z=2.093,P<0.05),但是与单独应用DWI的AUC之间的差异无统计学意义(Z=0.905,P=0.365);T2WI鉴别前列腺移行区良恶性结节的AUC低于DWI的,但两者之间的差异无统计学意义(Z=1.629,P=0.103),2种序列结合鉴别前列腺移行区良恶性结节的特异度和敏感度最高.结论 前列腺移行区恶性结节的ADC值明显低于良性结节;联合应用DWI和T2WI鉴别诊断良恶性结节的特异度和敏感度最高.     

MRI动态增强扫描联合DTI对前列腺中央区良恶性结节的诊断价值

目的：探讨MRI动态增强扫描（DCE-MRI）、DTI联合检查对前列腺中央区良恶性结节的诊断价值。方法：选取行前列腺MRI扫描的50例泌尿外科患者,共发现59个结节,其中前列腺癌（PCa）结节20个（PCa组）,良性前列腺增生（BPH）结节39个（BPH组）,均行T₂WI、DCE及DTI扫描,观察检查结果。结果：PCa组的ADC值显著低于BPH组,各向异性分数值均显著高于BPH组（均P<0.05）,2组峰值时间值及曲线斜率值比较差异均有统计学意义（均P<0.05）,而强化率比较差异无统计学意义（P>0.05）;2组TIC比较差异有统计学意义（P<0.05）;DTI、DCE及两者联合诊断良恶性结节的特异度均>80%,DCE扫描的敏感度较低,3种诊断技术的ROC曲线下面积比较,联合诊断最大。结论：DTI与DCE联合检查对前列腺中央区良恶性结节的诊断具有更高的临床价值,值得推广应用。     

ADC直方图分析法鉴别中央带前列腺癌与T2WI低信号增生结节的研究

目的:探讨表现扩散系数(ADC)直方图分析法鉴别诊断中央带前列腺癌和T2 WI低信号增生结节的效能.方法:回顾性分析29例中央腺体(CG)前列腺癌患者(前列腺癌组)和24例T2WI低信号增生结节患者(增生结节组)的MRI图像,所有患者行磁共振DWI检查,b值为0、1000 s/mm2.在MR上确定前列腺癌和增生结节病灶,并与病理结果对照.计算并比较两类病变的平均ADC(ADCmean)值和第10百分位数ADC值(10％ ADC).用受试者工作特性曲线(ROC)分析10％ ADC和ADCmean鉴别CG前列腺癌与T2 WI低信号增生结节的效能.结果:共计32处前列腺癌病灶和28处增生结节纳入研究,增生结节的10％ ADC和ADCmean值分别为(0.81±0.14)×101、(1.03±0.17)×10-3mm2/s,前列腺癌10％ ADC和ADCmean值为0.64±0.12和0.83±0.15,均明显低于增生病变(P＜0.05).10％ADC值鉴别前列腺癌和增生结节的ROC曲线下面积(AUC)为0.87,明显高于ADCmean(0.81) (P＜0.05).结论:表观扩散系数直方图有助于提高中央带前列腺癌与T2 WI低信号增生结节的鉴别诊断.     

T2WI低信号的前列腺外周带病变的MR诊断研究

目的：探讨磁共振T2加权相（T2WI）表现为低信号的前列腺外周带病变的诊断研究。方法：对83例前列腺外周带病变,其中前列腺炎症25例、前列腺腺癌45例、前列腺增生10例、纤维化病灶3例,进行T1WI、T2WI、DWI扫描,其中55例进行了增强扫描,分析前列腺外周带病变的信号表现。所有病例均经手术或穿刺活检病理证实。同时分析83例患者的PSA值。结果：前列腺外周带炎症T2WI的低信号影大部呈斑片状,无占位效应,增强后时间-信号曲线呈平台型,DWI呈稍高信号,ADC值稍减低,血PSA值处于正常值上限附近;前列腺外周带癌灶T2WI的低信号影以结节状为主,增强后时间-信号曲线呈速升速降型,DWI呈明显高信号影,ADC值明显降低,血PSA值明显增高;前列腺外周带良性前列腺增生T2WI的低信号呈斑片状或结节状,增强后早期无明显强化,后期不均匀强化,DWI呈稍高或高信号,ADC值稍低,介于腺癌与炎症之间,常可见中央带增生表现,血PSA值稍高;前列腺外周带纤维化病灶T2WI的低信号呈斑条状,界清,DWI呈低信号,增强后无强化,血PSA值正常。结论：前列腺外周带的炎症、腺癌、增生、纤维化病灶T2WI均可表现为低信号,增强扫描及DWI检查,ADC值测量,并结合PSA值,有较大诊断价值。     

MR波谱脂峰对前列腺中央腺体谱线的影响

目的探讨MR波谱（MRS）中脂峰对前列腺中央腺体谱线的影响。方法对17例因良性前列腺增生（BPH）行经尿道前列腺切除术（TURP）患者的MRS谱线作回顾性分析，根据病理结果分为3组：中央腺体偶发癌（IDPC）组4例、腺体增生为主的BPH（glandular BPH，GBPH）组7例，基质增生为主的BPH（stromal BPH，SBPH）组6例。统计中央腺体感兴趣区内出现脂峰的体素，并与病理结果对照，分析脂峰在中央腺体出现的常见位置及对MRS谱线识别产生的干扰。结果位于中央腺体的MRS体素共3567个，有脂峰体素834个，占中央腺体总体素的22．8％。其中，GBPH、SBPH和IDPC组测量的体素数分别为1477、1434和656个，有脂峰体素分别为397、396和41个。上述3组患者有脂峰体素所占比率的中位数分别为23．6％、27．2％和6．4％。有脂峰体索多位于中央腺体的边缘，3组所占比率的中位数分别为79．6％、68．6％和72．4％。脂峰多不会对谱线识别造成干扰，3组所占比率中位数分别为82．8％、98．0％和96．4％。结论前列腺中央腺体的MRS谱线中，脂峰可能与腺体周围脂肪组织有关，而且大多数未影响到谱线的识别。     

前列腺中央腺体癌肿MRI多项技术成像的影像诊断

目的 探讨MRI多项技术成像应用在前列腺中央腺体癌肿的诊断与鉴别诊断中的价值.方法 收集并分析经过手术、穿刺后病理或经临床治疗后证实的21例前列腺中央腺体有癌肿患者的资料,所有患者均进行多项MRI技术成像：T2WI、扩散加权成像、波谱及动态增强扫描.结果 多项技术成像检查上能够显示前列腺中央腺体癌灶的形态、侵犯的范围,准确定性且能预测恶性程度;主要依据为常规T2WI序列上显示欠清,在DWI图像上则为高信号,在相应ADC图上呈低信号改变,波谱成像Cho峰明显升高,Cit峰下降,两峰呈倒置状态,病灶在增强后出现早期明显强化,时间-强化曲线为流出型.结论 MRI多项技术影像具有特征性,可提高前列腺中央腺体癌肿检出率及诊断率,在临床上有较高的应用价值.     

前列腺中央腺体偶发癌与中央腺体癌的MR扩散加权成像

目的:运用MR扩散加权成像对前列腺中央腺体偶发癌和中央腺体癌的表现扩散系数值(ADC值)进行定量分析.方法:回顾性分析8例前列腺中央腺体偶发癌和32例中央腺体癌患者病例资料,比较两者ADC值.结果:①中央腺体ADC值:前列腺中央腺体偶发癌组与中央腺体癌组分别为(1.48±0.18)×10-3mm2/s、(1.20±0....     

前列腺外周带癌T 2 WI影像特征的多因素分析

目的：探讨前列腺外周带癌 T2 WI 影像特征的诊断价值。方法回顾性分析经病理证实的56例外周带前列腺癌的T2 WI图像,另选取75例前列腺增生、7例前列腺炎作为对照组,应用χ2检验对各影像特征进行筛选,再采用多因素Logistic回归分析。结果 T2 WI上病灶的信号强度、形态、均匀度、患侧外周带体积、患侧外周带与移行区分界、前列腺包膜在外周带前列腺癌与对照组的差异均有统计学意义(P<0.05),病灶的边界、包膜在2组间的差异无统计学意义(P>0.05)。多因素Logistic回归发现影响外周带前列腺癌的危险因素为病灶的形态、患侧外周带体积、前列腺包膜、外周带与移行区分界。结论 T2 WI 上病灶的形态、患侧外周带体积及前列腺包膜是诊断外周带前列腺癌的独立危险因素。     

磁共振DWI结合T_2WI在前列腺疾病诊断中的价值

目的：探讨磁共振DWI结合T2WI在前列腺良恶性疾病诊断中的价值。方法：53例经组织病理学及随访证实的前列腺疾病患者,其中前列腺癌（PCa）15例,前列腺增生（BPH）38例,行磁共振平扫及DWI,测量其表观扩散系数（ADC）及病灶与周围正常外围带ADC值的相对比值,经2名有经验的医师进行双盲阅片,比较T2WI及DWI结合T2WI对PCa、BPH的定性诊断准确率。结果：T2WI对PCa、BPH的定性诊断准确率分别为73.3%、65.8%,DWI结合T2WI对PCa、BPH的定性诊断准确率分别为86.7%、92.1%。结论：DWI结合T2WI能提高前列腺疾病的定性诊断准确率,DWI及ADC值在一定程度上有助于前列腺良恶性病变的鉴别。     

前列腺中央腺体癌3.0 T MRS的初步研究

目的 :分析前列腺中央腺体癌3.0 T MRS表现,探讨其诊断价值。方法 :回顾性分析经手术病理证实的11例前列腺中央腺体癌的3.0 T MRI及MRS表现,比较中央腺体癌区及非癌区(胆碱+肌酸)/枸橼酸盐[(Cho+Cre)/Cit]的比值。结果:MRI检查11例均表现为中央腺体增大;2例中央腺体区信号不均匀,见不规则低信号;8例中央腺体区示低、稍高混杂信号结节;1例中央腺体区弥漫性低、等混杂信号结节,侵入外周带。MRS测得中央腺体癌区(Cho+Cre)/Cit值为2.75±1.34,范围1.12~5.67;非癌区(Cho+Cre)/Cit值为0.65±0.32,范围为0.17~0.98,两者差异有统计学意义(P<0.05)。结论:前列腺中央腺体癌3.0 T MRI信号复杂多样,常规序列不易检出、定性困难;MRS能提供中央腺体癌的代谢信息,有助于提高中央腺体癌的诊断水平。     

Diffusion-weighted MRI in cervical lymph nodes: Differentiation between benign and malignant lesions

Objective

Purpose of our study was to assess the potential role of diffusion-weighted imaging (DWI) in the differential diagnosis between benign and malignant nodes.

Subject and methods

We enrolled 32 subjects: 14 with benign lymphadenopathy, 17 patients with histologically proved malignant disease before beginning treatment and 1 patient with lymphoma after chemotherapeutic treatment.In all patients we used fast spin echo T2-weighted images in axial and coronal planes, fast spin echo T1-weighted images before and after contrast medium of administration in axial and coronal planes.Before contrast administration diffusion sequences were acquired on the axial and coronal plane (b factor of 0.500 and 1000 s/mm²) and then apparent diffusion coefficient (ADC) maps were reconstructed.

Results

On diffusion images, 13/14 patients with benign nodes showed low signal intensity and had high signal on ADC maps, whereas all patients with malignant diseases appeared hyperintense on diffusion images and with low signal intensity on ADC maps. Only a patient with tuberculosis showed a low ADC value. The mean ADC value of malignant nodes was about 0.85 × 10⁻³ mm²/s, the mean value of benign nodes was 1.448 × 10⁻³ mm²/s; this difference was statistically significant (p < 0.01). The mean ADC value of treated nodes was 1.75 × 10⁻³ mm²/s. The best threshold value was 1.03 × 10⁻³ mm²/s, obtaining a sensitivity of 100% and a specificity of 92.9%.

Conclusions

Diffusion imaging could be considered an important supportive tool for the diagnosis of enlarged cervical lymphadenopathies.     

The association of enlarged periportal lymph nodes on T2 WI with chronic hepatitis B

目的:探讨T2 WI肝门区淋巴结与慢性乙肝炎症活动度(G)和纤维化程度(S)的关系.方法:经病理证实的慢性乙型肝炎32例,健康成人18例(对照组).在MR脂肪抑制T2 WI上观察肝门区短径＞5 mm淋巴结的数目、大小和相对信号强度,并分析其与慢性乙型肝炎G和S的关系.结果:肝门区短径＞5 mm的淋巴结预示G2及以上炎症活动(P＜0.05),淋巴结数目≥2为最佳诊断点,敏感度和特异度分别为79.31％和90.47％;淋巴结的存在与S无关.淋巴结的大小与G有相关性(r=0.362,P=0.010),与S无相关性(r=-0.046,P=0.753);淋巴结的相对信号强度与G(r=0.260,P=0.071)和S(r=0.031,P=0.831)均无相关性.淋巴结的大小预示G2及以上炎症活动准确性较高(ROC曲线下面积=0.920,P＜0.001),以＞90 mm2为最佳诊断点,敏感度和特异度分别为89.66％和80.95％.结论:MR脂肪抑制T2 WI能显示慢性乙肝肝门区肿大淋巴结.肝门区出现2个及以上、短径＞5 mm淋巴结或淋巴结大小＞90 mm2提示G2及以上炎症活动.     

Differential diagnosis of intracranial lesions with high signal on T1 or low signal on T2-weighted MRI

Magnetic resonance imaging (MRI) is the preferred technique for examining intracranial pathology in the non-acute setting in most cases. The aim of this review is to demonstrate the imaging appearances on unenhanced spin-echo MRI of lesions that show characteristic, unusual signal changes, which occur due to the presence of fat, cholesterol, paramagnetic substances, rapidly flowing fluids, air, cortical bone or calcification. The nature of the MRI signal, together with the anatomical location of the lesion should allow the provision of a narrow differential diagnosis, before the use of intravenous contrast medium or additional imaging sequences.     

磁共振快速T1加权序列在腹部疾病中的应用选择

目的　探讨磁共振快速T1加权序列各成像技术及其在腹部疾病中的应用。方法　对 45例可疑腹部疾病的患者先采用T2 加权快速自旋回波 (T2 WI/TSE)序列扫描 ,再加扫快速多层绕相梯度回波 (DUAL/FFE)、选择水激励梯度回波 (sT1WI/WATS/FFE)及三维超快速梯度回波 (3D/T1WI/TFE)序列进行扫描。结果　 45例中 6例正常 ,3 9例异常。 3种快速T1WI序列中 ,DUAL/FFE(OP)序列对检测腹部含脂质病变较为敏感。sT1WI/WATS/FFE序列对检测胰腺病变较为敏感 ,3D/T1WI/TFE序列对于肝脏结节性病变较为敏感。结论　在MRIT2 WI/TSE序列的基础上合理地结合与DUAL/FFE(OP)、sT1WI/WATS/FFE、3D/T1WI/TFE序列 ,可更好地显示腹部各病变的特征 ,提高诊断准确率。     

The detection and discrimination of malignant and benign focal hepatic lesions: T2 weighted vs diffusion-weighted MRI

Objective

The purpose of this study was to evaluate the use of diffusion-weighted imaging (DWI) for the detection and characterisation of focal hepatic lesions compared with the use of T₂ weighted imaging.

Method

45 patients with 97 hepatic lesions (51 malignant lesions and 46 benign lesions) were included in this retrospective study. Malignant hepatic lesions included 12 hepatocellular carcinomas, 26 metastases and 13 intrahepatic cholangiocarcinomas. Benign hepatic lesions included 19 haemangiomas and 27 cysts. The MRI protocol for the upper abdomen included T₂ weighted images, in- and opposed-phase T₁ weighted images and dynamic T₁ weighted images. Breath-hold fat-suppressed single-shot echo planar DWI was performed with the following parameters: 1338/66; b factors, 0, 50 and 800 s mm^–2. Two independent observers reviewed the T₂ weighted images and the DWI to detect and to characterise the hepatic lesions.

Results

For detection of malignant hepatic lesions, the use of DWI showed a significantly higher detection rate than the use of T₂ weighted images (p<0.05). However, there was no significant difference between the use of DWI and T₂ weighted images for benign hepatic lesions. For the differentiation between malignant and benign hepatic lesions, there was no significant difference in sensitivity, specificity and accuracy between the use of T₂ weighted images and the use of DWI.

Conclusion

The use of DWI was better for the detection of malignant hepatic lesions than the use of T₂ weighted images. However, for detection of benign hepatic lesions and characterisation of hepatic lesions, the use of DWI was equivalent to the use of T₂ weighted images.Accurate detection and characterisation of focal hepatic lesions is important for treatment planning in patients with hepatic tumours. For the detection and characterisation of hepatic lesions, CT and MRI are usually employed [1^,2]. MRI, T₁ weighted, T₂ weighted and gadolinium-enhanced T₁ weighted imaging have been commonly utilised [3^,4].With rapid progress of the use of parallel imaging techniques such as sensitivity encoding (SENSE), the quality of diffusion weighted single-shot echo-planar imaging has improved [5]. Diffusion-weighted MRI of the abdomen has become possible by the use of this technique, which reduces acquisition time, minimises echo-planar imaging artefacts and improves the quality of images [5].Several studies have characterised focal hepatic lesions by measurement of the lesion apparent diffusion coefficient (ADC) [6-11] and have evaluated detection of focal hepatic lesion by use of diffusion-weighted imaging (DWI) [12-16]. However, there is still controversy regarding the value of DWI for the characterisation of focal hepatic lesions as the ADC values of different types of lesions overlap [6-11]. Furthermore, a limited number of studies have been performed using DWI for the detection of hepatic lesions [12-16].The purpose of this study was to evaluate the use of DWI for the detection and characterisation of focal hepatic lesions compared with the use of T₂ weighted imaging.     

T2WI MRI and MRI-MDCT correlations of the osteoporotic vertebral compressive fractures

Purpose

The purpose of this study was to present the various vertebral bone signal and configuration patterns on T2WI MRI in osteoporotic benign fractures. The appearances were also assessed with thin slice MPR CT images.

Materials and methods

66 patients (43 women, 23 men; age range, 34–97 years; mean age, 76 years) with 100 vertebral compression fractures due to osteoporosis were included in our study. All cases are acute or subacute phase fractures which occurred within 1 month. Multiple fractures were observed in 29 patients, in 8 cases multiple concurrent fractures were proved by past radiograph or MRI. Three planes of T2WI (sagittal, coronal, axial) section images were correlated with the corresponding MDCT images.

Results

In our retrospective study, various signals and forms of vertebral body fractures were observed. The fracture zone (line) was classified 3 signal intensity patterns. (high; n = 24, low to intermediate; n = 16, low intensity; n = 38) on T2WI. The signal of the peri(para) fractured area were high (n = 6), intermediate to low (n = 41), low (n = 53)intensity. With CT correlative study, high, low to intermediate area were considered to be corresponded to the bone marrow edema, fibrous reparative tissue with/without the bony callus formation. The localization were as follows: sub-end plate band like lesion in 53, central in 16, anterior in 13, sub-endplate + anterior in 10, and complete (diffuse) in 8. In 10 cases, adjacent Schmorl's nodules were observed.

Conclusion

The various vertebral body signal patterns were observed in osteoporotic compressive fracture on T2WI. By MRI-CT correlations, high signal and low signal area on T2WI corresponded to the bone marrow edema, and the fibrous tissue or callus formation respectively.