定量动态增强MRI鉴别乳腺良恶性病变的研究

目的 探讨定量动态增强MRI鉴别乳腺良恶性病变的价值.方法 118例乳腺疾病患者行3.0 T定量动态增强MR检查,测量定量参数:容量转移常数(Ktrans)、速率常数(Kep)和血管外细胞外间隙容积比(Ve),对恶性病变、良性病变及正常腺体组间定量参数行单因素方差分析及LSD法两两比较;对浸润性癌与导管原位癌组间行独立样本t检验;最后绘制ROC曲线.结果 恶性病变组Ktrans、Ken、Ve均值分别为(1.010±0.580)min-1、(1.634±1.481)min-1、(0.735±0.273);良性病变组三者均值分别为(0.331±0.192)min-1、(0.417±0.324)min-1、(0.847±0.291);正常腺体组间三者均值分别为(0.051±0.028)min-1、(0.133±0.125)min-1、(0.597±0.354).正常腺体与良性病变、正常腺体与恶性病变及良性病变与恶性病变间Ktrans差异均有统计学意义(t值分别为9.681、11.189、5.590,P值均＜0.01);正常腺体与恶性病变、良性病变与恶性病变间Kep差异有统计学意义(t值分别为5.287、3.874,P值均＜0.05);正常腺体与良性病变、正常腺体与恶性病变间Ve差异有统计学意义(t值分别为2.932、2.562,P值均＜0.05);正常腺体与良性病变间Kep、良性病变与恶性病变间Ve差异无统计学意义(t值分别为0.760、0.832,P值均＞0.05).浸润性癌与导管原位癌组间Ktrans、Kep、Ve差异均无统计学意义(t值分别为0.834、0.075、0.454,P值均＞0.05).Ktrans、Kep、Ve三者ROC曲线下面积分别为0.934、0.941、0.659,以最大约登指数为最佳诊断切点值,则三者判断乳腺良恶性病变的敏感性分别为77.01%、91.95%、56.32%;特异性分别为95.65%、86.96%、78.26%.结论 定量动态增强参数Ktrans、Kep值可以对乳腺良恶性病变做出鉴别诊断,并表现出相对高的诊断效能,但对浸润性癌与导管原位癌鉴别效能较低.

Abstract：

Objective To evaluate the value of quantitative 3T dynamic contrast enhanced MRI in the diagnosis of breast lesions. Methods One-hundred and eighteen patients suspected of breast lesions underwent MRI examination. A 3.0 T MR scanner was used to obtain the quantitative MR pharmacokinetic parameters: Ktrans( volume transfer constant), Kep (exchange rate constant) and Ve (extravascular extracellular volume fraction). The mean Ktrans, Kep and Ve of malignant, benign and normal glandular tissues were calculated and compared each other using LSD method. Independent sample t test was used between invasive ductal carcinoma and ductal carcinoma in situ (microinvasion included). Finally, the areas under the ROC curve (AUC) of Ktrans, Kep and Ve between malignant and benign lesions were compared. Results The mean Ktrans, Kep and Ve of malignant lesions (n=87) were (1.010±0.580) min-1, (1.634 ± 1.481) min-1 and (0.735 ±0.273); the mean Ktrans, Kep and Ve of benign lesions (n=23) were (0.331±0.192) min - 1, (0.417±0.324) min - 1 and (0.847±0.291); and the mean Ktrans, Kep and Ve of normal glandular tissues (n =83) were (0.051 ±0.028) min-1, (0.133±0.125) min-1 and (0.597±0.354), respectively. There were significant differences between normal glandular tissues and benign lesions, normal glandular tissues and malignant lesions, benign and malignant lesions in Ktrans (t=9.681, 11.189, 5. 590, respectively, P ＜ 0. 01 ), normal glandular tissues and malignant lesions, benign and malignant lesions in Kep(t =5. 287, 3. 874, P＜0. 05). There were a statistic differences between normal glandular tissues and benign lesions, normal glandular tissues and malignant lesions in Ve(t =2. 932, 2. 562 ,P ＜0. 05). There were no significant differences between normal glandular tissues and benign lesions in Kep, benign and malignant lesions in Ve ( t = 0. 760, 0. 832, P ＞ 0.05 ),invasive ductal carcinoma and ductal carcinoma in situ (microinvasion included) in Ktrans, Kep and Ve(t =0.834,0.075,0.454,P＞0.05). The areas under the ROC curve (AUC) of Ktrans, Kep and Ve between malignant and benign lesions were 0. 934, 0. 941 and 0. 659. The sensitivity of Ktrans, Kep and Ve were 77.01% ,91.95% ,56. 32% and the specificity of Ktrans, Kep and Ve were 95. 65%, 86. 96%, 78.26% for the differential diagnosis of breast lesions if taken the maximum Youden's index as cut-off. Conclusion The differential diagnosis of benign and malignant breast lesions by Ktrans, Kep is applicable.     

CT及MRI在下颌下腺病变中的影像进展

下颌下腺为仅次于腮腺的第二大涎腺,邻近解剖结构复杂,病种多样。影像检查是重要的辅助检查手段,CT及MRI不仅可以提供病灶详细的解剖学信息,还能有效评估病灶性质。CT及MR灌注成像、双能量CT、扩散加权成像（DWI）及其衍生序列和体素内不相干运动（IVIM）等新技术可对肿瘤良恶性以及肿瘤性病变与感染性疾病的鉴别提供更多信息。就涎腺病变的CT和MRI研究进展予以综述,旨在探索CT及MRI新技术应用于下颌下腺成像的可能性。     

常规MRI联合DWI在腮腺常见肿瘤中的诊断价值

目的:探讨常规MRI联合DWI对腮腺常见肿瘤的诊断价值。方法:回顾性分析经病理证实的62例腮腺肿瘤的MRI图像,根据其DWI图行ADC图重建,测量肿瘤的ADC值。按发病率将62例病例分成3组:多形性腺瘤、腺淋巴瘤、恶性肿瘤。多形性腺瘤31例,全部单发;腺淋巴瘤19例,9例单发,10例多发,共30个病灶;恶性肿瘤12例,3例淋巴瘤多发,其余均为单发,共18个病灶。比较分析3种肿瘤的ADC值。结果:多形性腺瘤和腺淋巴瘤多发生于腮腺浅叶(43个,70.5%),肿瘤边界多清楚,体积一般较恶性肿瘤小;恶性肿瘤位于深叶者8个(44.4%),边界清楚或不清楚,多伴有颈部淋巴结肿大(10例,83.3%)。多形性腺瘤及恶性肿瘤平均ADC值均高于腺淋巴瘤(P=0.000、0.002),且多形性腺瘤平均ADC值高于恶性肿瘤(P=0.001)。结论:腮腺肿瘤的常规MRI征象具有一定特点,联合DWI能为腮腺常见肿瘤的诊断及鉴别诊断提供更多依据。     

磁共振波谱及扩散加权成像在唾液腺肿瘤诊断中的价值

目的 回顾性分析、评价氢质子磁共振波谱(~1H-MRS)及扩散加权成像(DWI)在鉴别唾液腺良性或恶性肿瘤中的价值.资料与方法 应用1.5 TMR成像仪,对39例唾液腺肿瘤患者进行常规MRI、DWI及~1H-MRS检查,(1)DWI采用单次激发自旋回波一回波平面成像(SE-EPI)序列,扩散敏感系数(b值)为0 s/mm~2及1000 s/mm~2,并计算每例患者平均表观扩散系数(ADC)值和高、中、低ADC值所占的比例,(2)~1H-MRS采用单体素点分辨表面线圈(PRESS)序列,TR 1500 ms,TE 136 ms,在谱线中计算胆碱与肌酸的比值(Cho/Cr).最后与肿瘤的组织病理学结果进行对比,进行非参数秩和检验.结果 39例唾液腺肿瘤患者均获得了满意的检查结果,其中良性肿瘤31例(混合瘤21例,腺淋巴瘤10例),恶性肿瘤8例(腺囊腺癌3例、黏液表皮样癌3例、混合腺癌1例、恶性淋巴瘤1例).(1)DWI:ADC图提示良性肿瘤与恶性肿瘤的平均ADC值分别为(1.65±0.41)×10~(-3)mm~2/s和(1.15±0.39)×10~(-3) mm~2/s,其间无明显差异,但良性肿瘤ADC值增高的区域则明显多于恶性肿瘤,尤其是混合瘤.(2)~1H-MRS:在TE为136 ms时共获得满意的波谱曲线35例,计算得出恶性肿瘤、腺淋巴瘤、混合瘤的Cho/Cr分别为1.69±0.51、5.89±1.42、2.81±0.72,恶性肿瘤、腺淋巴瘤、混合瘤之间均存在显著差异.结论 DWI及~1H-MRS可以作为鉴别唾液腺肿瘤的特异性检查手段,但仍需要大量研究样本来进行验证.     

Imaging of salivary gland tumours

Salivary gland neoplasms account for <3% of all tumors. Most of them are benign and parotid gland is the commonest site. As a general rule, the smaller the involved salivary gland, the higher is the possibility of the tumor being malignant. The role of imaging in assessment of salivary gland tumour is to define intra-glandular vs. extra-glandular location, detect malignant features, assess local extension and invasion, detect nodal metastases and systemic involvement. Image guided fine needle aspiration cytology provides a safe means to obtain cytological confirmation. For lesions in the superficial parotid and submandibular gland, ultrasound is an ideal tool for initial assessment. These are superficial structures accessible by high resolution ultrasound and FNAC which provides excellent resolution and tissue characterization without a radiation hazard. Nodal involvement can also be assessed. If deep tissue extension is suspected or malignancy confirmed on cytology, an MRI or CT is mandatory to evaluate tumour extent, local invasion and perineural spread. For all tumours in the sublingual gland, MRI should be performed as the risk of malignancy is high. For lesions of the deep lobe of parotid gland and the minor salivary glands, MRI and CT are the modalities of choice. Ultrasound has limited visualization of the deep lobe of parotid gland which is obscured by the mandible. Minor salivary gland lesions in the mucosa of oral cavity, pharynx and tracheo-bronchial tree, are also not accessible by conventional ultrasound. Recent study suggests that MR spectroscopy may differentiate malignant and benign salivary gland tumours as well as distinguishing Warthin's tumor from pleomorphic adenoma. However, its role in clinical practice is not well established. Similarly, the role of nuclear medicine and PET scan, in imaging of parotid masses is limited. Sialography is used to delineate the salivary ductal system and has limited role in assessment of tumour extent.     

Giant epithelial-myoepithelial carcinoma of the parotid gland

We present the case of an elderly woman with a painless giant tumor of the neck. Computed tomography (CT) demonstrated a cyst-like lesion that appeared to arise from the parotid gland. The tumor was removed in toto and histopathologically diagnosed as an epithelial–myoepithelial carcinoma. Such rare carcinomas should be considered in the differential diagnosis of parotid gland malignancies. We discuss the possibilities of imaging modalities such as CT and magnetic resonance imaging (MRI) in the differentiation between benign and malignant salivary gland tumors.     

3.0T MR动脉自旋标记对腮腺肿瘤的鉴别诊断价值

目的:初步探讨3.0T磁共振动脉自旋标记技术(ASL)对腮腺肿瘤的鉴别诊断价值。方法:前瞻性搜集2017年3月-2020年1月因腮腺肿物于本院就诊及治疗的患者作为研究对象,所有研究对象均行常规MR平扫及ASL扫描,测量ASL序列图像上肿瘤组织的肿瘤血流量(TBF),并将计算出的标准化肿瘤血流量(nTBF)与病理结果进行对比分析。结果:本研究总共纳入45例经术后病理证实的腮腺肿瘤患者。其中良性肿瘤28例,包括腺淋巴瘤14例,多形性腺瘤14例;恶性肿瘤共17例。测量并经计算得出腺淋巴瘤、多形性腺瘤、恶性腮腺肿瘤的nTBF分别为:3.71±1.65、0.89±0.25、1.55±0.60。腺淋巴瘤的nTBF明显高于多形性腺瘤(P<0.01)和恶性肿瘤(P<0.01),但是多形性腺瘤和恶性肿瘤的nTBF差异无统计学意义(P=0.073)。ASL能将腮腺腺淋巴瘤从多形性腺瘤及恶性肿瘤中鉴别出来,但是无法鉴别多形性腺瘤与恶性肿瘤。ASL诊断腮腺腺淋巴瘤的ROC曲线下面积为0.935,nTBF的诊断阈值为2.03,诊断腺淋巴瘤的敏感度和特异度分别为92.9%、93.5%。结论:3.0T MR ASL技术可以无创地、定量地评价腮腺肿瘤的TBF,并对腺淋巴瘤的诊断和鉴别诊断具有较高的价值。     

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.     

定量动态增强 MRI在脑胶质瘤术前分级中的应用研究

目的：探讨定量动态增强 MRI(T1-DCE MRI)在脑胶质瘤术前分级中的应用价值。方法经手术病理证实的80例脑胶质瘤患者(WHOⅠ级20例,Ⅱ级20例,Ⅲ级20例,Ⅳ级20例)均行3T 常规 MR 增强及 T1-DCE MRI 检查,原始灌注图像数据经 GE Omni Kinetic 软件处理,获得容量转移常数(Ktrans )、回流速率常数(Kep )和血管外细胞外间隙容积比(Ve )图,选择感兴趣区(ROI),计算 Ktrans 、Kep 和 Ve 值。不同级别胶质瘤 Ktrans 、Kep 和 Ve 值与病理分级进行 Pearson 相关性分析,不同级别胶质瘤 Ktrans 、Kep 和 Ve 值比较采用单因素方差分析。绘制受试者工作特征曲线(ROC)分析灌注参数的诊断特异性、敏感性。结果Ktrans 、Kep 和Ve 值与病理学分级具有明显相关性(r=0.951,0.804,0.766)。Ktrans 值不同级别胶质瘤患者间比较有明显的统计学差异,Kep 值除Ⅱ级和Ⅲ级间比较无差异外,余不同级别间比较均有统计学差异,Ve 值除Ⅰ级和Ⅱ级,Ⅲ级和Ⅳ级间比较无差异外,余不同级别间比较有统计学差异。根据 ROC,Ktrans 对于诊断不同级别胶质瘤具有较高的敏感性和特异性。以 Ktrans 值0.160,0.420和0.935为最佳诊断切点值,诊断不同级别胶质瘤的敏感性分别为90%,95%和95%,特异性分别为95%,95%和85%。结论通过 T1-DCE MRI 所得参数Ktrans 值对不同级别胶质瘤微血管灌注状态进行定量分析,可以评估肿瘤血管血脑屏障的破坏程度,在术前较为精确地评价胶质瘤级别。     

腮腺多形性腺瘤与沃辛瘤MRI表现对照分析

目的:探讨磁共振成像检查对腮腺多形性腺瘤与沃辛瘤的鉴别诊断价值。方法:回顾分析经病理证实的8例腮腺多形性腺瘤及10例腮腺沃辛瘤的磁共振成像检查表现,并作统计学处理。结果:腮腺多形性腺瘤为单侧腮腺单发病灶(8/8),沃辛瘤可单侧单发(5/10),亦可双侧或多发(5/10)(P<0.05);沃辛瘤多位于腮腺浅叶(13/17),腮腺多形性腺瘤可位于浅叶(6/8),亦可位于深叶或占据深浅叶(2/8)(P<0.05);多形性腺瘤在T2WI中以高信号多见(5/8),沃辛瘤以等信号或低信号为主(17/17)(P<0.05);性别分布上腮腺多形性腺瘤女性多见(6/8),沃辛瘤男性多见(7/10)(P<0.05);年龄分布上沃辛瘤为50岁以上者多见(6/10),多形性腺瘤中50岁以上与50岁以下者分布相近,各为4例(P<0.01)。结论:磁共振成像检查的特征表现和临床资料相结合对腮腺多形性腺瘤与沃辛瘤可正确诊断。     

Diagnostic value of FDG PET and salivary gland scintigraphy for parotid tumors

PURPOSE: The purpose of this study was to examine the diagnostic value of the combination of F-18 fluorodeoxyglucose (FDG) PET and Tc-99m pertechnetate salivary gland scintigraphy in parotid tumors. MATERIALS AND METHODS: Seventy-two patients with benign parotid gland tumors (n = 52), malignant parotid tumors (n = 12), and inflammation (n = 8) underwent both FDG PET and salivary gland scintigraphy within 1 week, and 66 of the patients also underwent gallium scintigraphy. All patients were negative on their first fine-needle aspiration (FNA). RESULTS: Malignant parotid tumors showed significantly higher FDG uptake (standard uptake values [SUVs]) than both benign tumors and inflammation, except in Warthin's tumor (5.82 +/- 3.95 vs. 2.07 +/- 1.33; P <0.01). Although the SUV values of Warthin's tumor and malignant parotid tumors overlapped somewhat, Warthin's tumor did demonstrate increased radiotracer uptake, and it was reliably distinguished from other parotid gland tumors by the use of salivary gland scintigraphy. Considering a SUV value >3 as being positive for malignancy and excluding Warthin's tumor on the basis of salivary gland scintigraphy, sensitivity and specificity of FDG PET were 75% and 80%, respectively. These results were superior to those of gallium scintigraphy (58% and 72%, respectively). CONCLUSIONS: Although the diagnostic value of FDG PET in the differentiation of malignant from benign parotid gland tumors was limited because of the high FDG uptake in some benign tumors, and particularly pleomorphic adenomas, combining salivary gland scintigraphy with FDG PET may help to negate this drawback, and this combination may be a more promising approach for differentiation of various parotid gland tumors in patients compared with nondiagnostic needle aspiration.     

MRI动态增强定量参数对肝细胞癌和肝良性肿瘤鉴别诊断的价值

目的：研究磁共振动态增强(DCE-MRI)定量参数在肝细胞癌和肝良性肿瘤鉴别的意义,探索定量参数对肝脏占位性病变良恶性诊断的界值及其诊断效能。方法对存在肝占位的25例患者进行 DCE-MRI 扫描,经病理证实或通过随访确诊肝细胞癌和肝良性肿瘤共28个病灶,利用 tissue4D 后处理软件测定病灶及周围正常肝组织的定量参数值(Ktrans 、Kep 、Ve 、iAUC),利用独立样本 t 检验比较肝细胞癌组、良性组病灶与周围正常肝组织的定量参数,同时比较2组病灶间的定量参数值,并通过绘制受试者工作特征曲线(ROC)来确定肝细胞癌和肝良性肿瘤间定量参数的最佳界值及其诊断效能。结果良性组、肝细胞癌组病灶的各定量参数均值大于周围正常肝组织,其中良性组 Ktrans 、iAUC 差异有统计学意义(P <0.05);肝细胞癌组 Ktrans 、Kep 、iAUC 差异有统计学意义(P <0.05);肝细胞癌组和良性组比较,肝细胞癌组病灶的各定量参数均值大于良性组,Ktrans 、Kep 及 iAUC 的差异有统计学意义(P <0.05)。其中 Ktrans =0.215 min-1时,敏感度为81.3%,特异度为66.7%,诊断效能大于 Kep (界值为0.477)、iAUC(界值为24.706)。结论DCE-MRI 定量参数能为肝细胞癌和良性肿瘤的鉴别诊断提供参考。     

腮腺囊实性肿瘤中不同成分对ADC均值的影响

目的：探讨在不同b值条件下,腮腺肿瘤中囊变区和实质区对表观扩散系数（ADC）均值的影响。方法：回顾性分析经手术病理证实并于术前行DWI检查的32例腮腺囊实性肿瘤（良性肿瘤22例,恶性肿瘤10例）的影像资料。分剐在b值为500和1000s／mm2时,对肿瘤整体、肿瘤实质区和肿瘤囊变区的ADC均值进行测量,并进行统计学分析。结果：b=500s／mm2时,肿瘤整体部分的ADC均值为（1．73±0．35）×10^-3mm^2／s,实质部分为（1．35±0．23）×10^-3mm^2／s,囊变部分为（2．44±0．31）×10^-3mm2／s。b=1000s／mm2时,肿瘤整体部分ADC均值为（1．35±0．28）×10^-3mm^2／s,实质部分为（1．12±0．22）×10^-3mm^2／s,裳变部分为（1．94±0．30）×10^-3mm^2／s。上述不同取样方法所测肿瘤ADC均值差异有统计学意义（P〈0．01）。实质部分的ADC均值在腮腺多形性腺瘤、腺淋巴瘤、其他良性肿瘤和恶性肿瘤之间差异亦有统计学意义（P〈0．01）。结论：腮腺肿瘤中囊变区和实质区ADC均值不同,从腮腺肿瘤实质区取样的ADC均值能为其鉴别诊断提供更多有益信息。     

DCE-MRI及多b值DWI对卵巢上皮源性肿瘤良恶性的鉴别诊断价值

目的:探讨动态对比增强MRI(DCE-MRI)及多b值DWI对卵巢上皮源性肿瘤良恶性的鉴别诊断价值。方法:搜集经术后病理证实为卵巢上皮源性肿瘤的39例患者,术前行常规MRI平扫及增强、多b值DWI及DCE-MRI检查,与术后病理结果进行对照,分别测量卵巢肿瘤实性区域及囊性区域的ADC值及DCE-MRI定量参数。采用ROC曲线分析良恶性肿瘤的最佳诊断阈值及相对应的诊断敏感度、特异度、阳性预测值、阴性预测值和诊断符合率(ACC)。结果:卵巢良、恶性上皮源性肿瘤实性部分各组间ADC值及囊性部分各组间ADC值差异均有统计学意义(P<0.05);DCE-MRI定量参数转移常数(Ktrans)值、速率常数(Kep)值及血管外细胞外间隙容积比(Ve)值在卵巢良、恶性上皮源性肿瘤实性部分中差异均有统计学意义(P<0.05)。ROC曲线分析结果显示,当b值=1200 s/mm 2时具有最佳诊断效能,肿瘤实性部分ADC值的最佳诊断阈值为1149.9 mm 2/s,AUC为0.874,诊断敏感度、特异度为88.2%、86.4%;肿瘤囊性部分ADC值的最佳诊断阈值为2640.2 mm 2/s,AUC为0.893,诊断敏感度、特异度为73.7%、88.2%;DCE-MRI定量参数Ktrans值在3个定量参数中具有最高诊断效能,其最佳诊断阈值为0.0925min-1,AUC为0.840,诊断敏感度、特异度为77.3%、82.4%。联合DCE-MRI、多b值DWI可明显提高卵巢上皮源性肿瘤的诊断效能,敏感度、特异度、阳性预测值、阴性预测值、诊断符合率分别为95.7%、100%、94.1%、100%、97.4%。结论:b值=1200 s/mm 2时的ADC值及Ktrans值对良、恶性卵巢上皮源性肿瘤具有较高的鉴别诊断效能,联合DCE-MRI及多b值DWI可明显提高卵巢上皮源性肿瘤的术前诊断符合率。     

磁共振肌纤维束成像在肌骨系统肿瘤诊断中的应用

目的 探讨扩散张量成像(DTI)及磁共振肌纤维束成像应用于骨肌系统肿瘤诊断的可行性及价值.资料与方法 38例骨肌系统肿瘤,均行常规MRI和DTI,计算并分析良、恶性肿瘤中心区、肿瘤周边区及邻近正常肌肉的部分各向异性值(FA)和体积比各向异性值(VrA),重组病变周围肌纤维束成像,并将MRI表现与手术病理学检查结果作对照研究.结果 良性肿瘤病变周围肌肉肌纤维束成像主要表现为肌肉推移征象.恶性肿瘤主要表现为浸润、破坏征象.良、恶性肿瘤周边区的FA值和VrA值相比差异均有统计学意义(P<0.01),良、恶性肿瘤中心区FA值和VrA值相比差异无统计学意义.结论 MR DTI能用于评价肌骨系统肿瘤的内部结构特征及与周围组织的关系,对良、恶性肌骨系统肿瘤的诊断及鉴别诊断有一定帮助.     

常规MRI及DCE-MRI在卵巢肿瘤及肿瘤样病变诊断中的应用

目的:提高常规MRI及DCE-MRI在卵巢肿瘤及肿瘤样病变的诊断准确率。方法:回顾性分析44例我院收治并经手术病理证实为卵巢肿瘤及肿瘤样病变的常规MRI及DCE-MRI影像表现。平扫参考指标:病灶大小(最大径)、形状(规则/不规则)、有无包膜、囊壁/分隔厚度、实性成分比例、T2WI信号、ADC值、盆腔积液;DCE-MRI参考Ktrans、Kep以及Ve值。结果:MRI平扫显示良、恶性肿瘤的病灶大小、形状、实性成分比例、囊壁/分隔厚度、T2WI信号混杂程度、盆腔积液量及ADC值差异有统计学意义(P<0.05);上述7项中ADC值参考价值最大,ADC取1.09×10^-3)mm^2/s为良恶性肿瘤阈值,小于阈值,考虑恶性。DEC-MRI良性肿瘤实性部分Ktrans、Kep以及Ve值显著低于恶性肿瘤,差异有统计学意义(P<0.05),Ktrans值参考价值最大,Ktrans值取0.091/min为良恶性肿瘤阈值,大于阈值,考虑恶性。分别以ADC值及Ktrans值敏感度、特异性、准确度、阳性预测值及阴性预测值代表MRI平扫及DCE-MRI各项指标,得出常规MRI敏感度85.7%、特异性91.3%、准确度88.6%、阳性预测值90.0%、阴性预测值87.5%;DCE-MRI上述各项指标为72.7%、81.8%、77.3%、80.0%、75.0%;常规MRI联合DCE-MRI检查敏感度95.2%,特异性100.0%,准确度97.7%,阳性预测值100.0%,阴性预测值95.8%。结论:常规MRI联合DCE-MRI用于卵巢肿瘤及肿瘤样疾病诊断及鉴别诊断能够提高诊断准确率。     

3.0TDCE-MRI及DTI在胶质瘤分级中的价值

目的：探讨动态增强磁共振成像(DCE-MRI)及扩散张量成像(DTI)在胶质瘤分级中的价值。方法31例胶质瘤患者行3.0T DCE-MRI 及 DTI 检查,测量定量参数包括：容量转移常数(Ktrans )、血管外细胞外间隙容积比(Ve )、速率常数(Kep )、对比剂浓度下峰面积(iAUC)及相对各向异性分数(rFA)。低级别、高级别胶质瘤组间 DCE-MRI、rFA 参数与微血管密度(MVD)、微血管结构(MVS)相关性评估采用 Spearman 相关性检验。结果胶质瘤分级与 MVD 计数和 MVS 改变呈正相关。14例低级别胶质瘤的 Ktrans 值、Kep 值、Ve 值、iAUC 值及 rFA 值分别为(0.02±0.01)min-1、1.82(0.18~8.54)min-1、0.05±0.03、2.47±1.66和0.55±0.22;17例高级别胶质瘤参数值分别为(0.11±0.02)min-1、1.31(0.12~7.58)min-1、0.28±0.10、10.84±6.46和0.28±0.08。各参数值组间除 Kep 外,其他参数差异均有统计学意义(P <0.05)。Ktrans 、Ve 、iAUC 值与 MVD 计数及 MVS 呈正相关(P <0.05),rFA 值与MVD 计数及 MVS 呈负相关(P <0.01)。结论DCE-MRI、DTI 定量参数对胶质瘤分级以及肿瘤新生血管增生、血管微结构改变都有重要的评估价值。     

CT and MR imaging findings of palatal tumors

Palatal tumors commonly arise from the minor salivary glands, and benign tumors account for approximately half of all minor salivary gland tumors. Minor salivary gland tumors have an affinity for the posterior hard palate and soft palate and virtually never arise in the midline, probably because of the distribution of palatal salivary glands. The majority of benign salivary gland tumors of the palate are pleomorphic adenomas, while the most common malignant salivary gland tumor is adenoid cystic carcinoma, followed by mucoepidermoid carcinoma, adenocarcinoma, and polymorphous low-grade adenocarcinoma. Epithelial tumors frequently arise from the soft palate. The majority of benign epithelial tumors of the palate are papillomas, while most malignant epithelial tumors are squamous cell carcinomas. Various types of mesenchymal tumors, including fibromas, lipomas, schwannomas, neurofibromas, hemangiomas, and lymphangiomas, also involve the palate. This article describes the CT and MR findings of benign and malignant palatal tumors.     

Effect of Arterial Deprivation on Growing Femoral Epiphysis: Quantitative Magnetic Resonance Imaging Using a Piglet Model

Objective

To investigate the usefulness of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion MRI for the evaluation of femoral head ischemia.

Materials and Methods

Unilateral femoral head ischemia was induced by selective embolization of the medial circumflex femoral artery in 10 piglets. All MRIs were performed immediately (1 hour) and after embolization (1, 2, and 4 weeks). Apparent diffusion coefficients (ADCs) were calculated for the femoral head. The estimated pharmacokinetic parameters (Kep and Ve from two-compartment model) and semi-quantitative parameters including peak enhancement, time-to-peak (TTP), and contrast washout were evaluated.

Results

The epiphyseal ADC values of the ischemic hip decreased immediately (1 hour) after embolization. However, they increased rapidly at 1 week after embolization and remained elevated until 4 weeks after embolization. Perfusion MRI of ischemic hips showed decreased epiphyseal perfusion with decreased Kep immediately after embolization. Signal intensity-time curves showed delayed TTP with limited contrast washout immediately post-embolization. At 1-2 weeks after embolization, spontaneous reperfusion was observed in ischemic epiphyses. The change of ADC (p = 0.043) and Kep (p = 0.043) were significantly different between immediate (1 hour) after embolization and 1 week post-embolization.

Conclusion

Diffusion MRI and pharmacokinetic model obtained from the DCE-MRI are useful in depicting early changes of perfusion and tissue damage using the model of femoral head ischemia in skeletally immature piglets.     

Oncocytoma: the vanishing parotid mass

Parotid gland oncocytoma is an uncommon, benign salivary neoplasm composed of mitochondria-rich oncocytes. The purpose of this study was to correlate MR imaging and histopathology of parotid gland oncocytomas and to define the features that may distinguish these neoplasms from other benign and malignant parotid gland tumors. The MR imaging features in 9 patients with a pathologic diagnosis of oncocytoma were retrospectively reviewed. The imaging features were strikingly similar for 8 of the 9 patients. All lesions appeared T1 hypointense but isointense to the native parotid gland on fat-saturated T2 and postcontrast T1 imaging. On MR imaging, parotid gland oncocytomas share specific imaging characteristics that have not been described for benign or malignant parotid gland tumors. Oncocytomas are isointense to native parotid gland on fat-saturated T2 and T1 postcontrast MR images. Preoperative identification of correct histology may help surgical planning.