鼻咽癌复发的增强前后MRI诊断

评价Gd-DTPA增强前后MR I在鼻咽癌放疗后复发(RNPC)与放射性纤维化(RF)鉴别诊断中的作用.材料和方法:对MR平扫显示鼻咽部或邻近区域有软组织肿块的28例鼻咽癌放疗后患者行Gd-DTPA增强MR I检查.RNPC22例,RF6例,炎性肿块2例,2例颅底RNPC分别合并鼻咽侧壁RF与炎性病灶.分析病灶形态及信号强度.结果:大多数RNPC病灶表现为TIWI上低信号TZWI高信号,RF在TIWI和T2WI上均显示低或中等信号,平扫两者信号强度区别在于T2WI上,但有一定重叠.增强扫描TIWI示绝大多数RNPC病灶(90.9%)有中度以上明显强化,而RF无或轻度强化,两者信号强度有显著性差异(P<0.01),且增强后肿瘤边界显示更清楚.病灶无强化,可除外RNPC,有强化则不一定是RNPC,明显强化可见于炎性病变.结论:肿块在MR平扫T2WI和增强后TIWI上的信号强度是鉴别RNPC与RF的主要依据,Gd-DTPA增强扫描有助于确定病变性质及其侵犯范围.     

鼻咽癌放疗后复发与纤维化DE-MRI的特征及病理对照研究

目的：探讨动态增强MRI技术对鼻咽癌放疗后复发与纤维化的鉴别诊断价值。方法;本研究中鼻咽癌放疗后复发患者15例,放疗后纤维化患者20例,均行三维容积内插法MRI扫描,获取病变区的时间一信号强度曲线（TIC）,测量并分析以下指标：MRI信号值（MRI值）、最大对比增强率（MCER）、最大对比增强率的时间（Tmax）。每例患者均取活检进行病理检查。结果：TIC类型：复发组中Ⅱ型（速升-平台型）12例,Ⅲ型（速升-缓降型）3例;纤维化组中I型（速升-缓升型）6例,Ⅱ型3例,Ⅳ型（缓升型）11例。在15～210S各时间点,复发组病灶的MRI值明显高于纤维化组,差异均有统计学意义（F=34．172～370．347,P〈O．001）;而在0S时,两组的MRI值差异无统计学意义（F=1．296,P-0．263）。复发组的MCER为13．64±0．52,明显高于纤维化组（6．50±1．05）,两组间差异有统计学意义（F=30．303,P〈0．001）。复发组Tmax明显早于纤维化组。结论：应用MRI动态增强技术分析MRI值、MCER指标可以鉴别诊断鼻咽癌放疗后复发与纤维化。     

鼻咽癌MRI动态增强曲线及其时间窗

目的：探讨MRI动态增强曲线及时间窗对鼻咽癌及其放疗后改变的诊断价值。方法：原发或经放射治疗后的鼻咽癌患者57例,将其分为3组,其中未经治疗组33例,放疗后纤维化组18例,放疗后复发组6例,所有病例治疗前的病理诊断均为鳞状细胞癌。观察和分析3组病例增强前后的MRI表现,采用FLASH序列获取3组病例的时间-信号强度曲线...     

鼻咽癌放疗后局部复发与纤维化的同层动态CT增强研究

目的：探讨螺旋CT动态增强扫描在鉴别鼻咽癌放疗后局部复发与纤维化中的应用价值。方法：选择鼻咽癌放疗后复发病人35例，纤维化者40例，行同层动态CT增强研究，绘制其时间．密度曲线。结果：鼻咽癌放疗后复发与纤维化的动态增强特点明显不同。结论：螺旋CT动态增强扫描有助于鉴别鼻咽癌放疗后复发与纤维化。     

鼻咽癌多层螺旋CT灌注成像的初步研究

目的探讨CT灌注成像技术对鼻咽癌(NPC)放疗后局部复发和放疗后纤维化的鉴别诊断价值。方法对正常人对照组20例、鼻咽癌治疗前组15例、鼻咽癌放疗后局部复发组14例和鼻咽癌放疗后纤维化组22例(4组共71例)研究对象进行鼻咽部CT灌注成像扫描,分析各组病灶区局部的时间密度曲线(TDC)和灌注参数特点及其差异。结果NPC治疗前组和放疗后复发组之TDC形态与其余2组明显不同;各组血流量(BF)均数两两比较差异均有显著性(Ρ<0.01);血容量(BV)和表面通透性(PS)值均数两两比较,除纤维化组与对照组之间差异无统计学意义外,其余各组间差异均有显著性(Ρ<0.05);平均通过时间(MTT)值均数两两比较,仅对照组与其余各组间差异有显著性(Ρ<0.01)。结论NPC放疗前、后局部不同病理结构的CT灌注参数和TDC具有不同特点。CT灌注成像技术对NPC放疗后局部复发和放疗后纤维化的鉴别诊断具有重要价值。     

鼻咽癌调强适形放疗前后动态增强特征的研究

目的探讨鼻咽癌调强适形放疗前后MRI动态增强灌注成像的时间-信号变化特征。方法选择初诊未治疗鼻咽癌患者326例,于调强放疗前后行MRI动态增强扫描,分析病灶放疗前后的时间-信号强度变化的曲线特征。结果鼻咽癌放疗前动态增强曲线多呈速升-速降型或速升-平台型,放疗后动态增强曲线多呈缓慢上升型或缓升-平台型。结论调强适形放疗不仅可以缩小鼻咽癌的肿瘤体积,治疗其局部侵犯和淋巴结转移,同时可有效抑制肿瘤的血管生成,降低肿瘤活性。     

鼻咽癌放疗后局部复发和纤维变的CT动态增强研究

目的探讨鼻咽癌放疗后局部复发和纤维变的CT动态增强特征。材料与方法放疗后纤维变组(RF组)86例，男54例，女32例。年龄21～62岁。放疗后复发组(RNPC组)52例，男37例，女15例．年龄27岁～68岁。先行鼻咽部平扫，然后选择“兴趣区”行同层动态增强扫描。采用ELSCINTCT-FLASH双螺旋CT扫描机，自动压力注射器注药。分别测量平扫与增强后不同时刻的CT值，进行统计学处理并描绘密度—时间曲线。结果(1)RF组动态增强曲线呈“缓升-缓降”型。(2)RNPC组动态增强曲线呈“速升-缓升-缓降”型。(3)注射造影剂后40～300s期间，RF组与RNPC组间各对应时刻点CT值均数均有显著性差异，RNPC组明显高于RF组。结论RF与RNPC的CT动态增强曲线及病变区CT值的明显差异可作为两者鉴别诊断的新依据。     

MRI动态增强扫描在前列腺癌诊断及鉴别诊断中的价值

目的　探讨动态增强MRI对前列腺癌诊断及鉴别诊断的价值。方法　对经病理证实的前列腺癌 10例及前列腺增生 30例行常规平扫及动态增强和延迟增强扫描 ,观察病灶的信号变化并绘制时间 /信号强度曲线。结果　前列腺癌在动态增强过程中 5例为早期强化 ,4例虽强化不显著 ,但与周围组织的信号差别增大 ,其时间 /信号强度曲线峰值位于早期及中期 ,1例灶性癌变者增强前后均未见明确癌灶 ;而前列腺增生表现为逐渐强化 ,峰值多位于晚期。结论　动态增强MRI使前列腺癌与周围组织的信号差别增大 ,有助于观察病灶 ;时间 /信号强度曲线在前列腺癌与增生的鉴别方面有一定价值     

肝再生性结节的MRI诊断

目的:总结肝再生性结节(RN)的MRI平扫及动态增强的表现,以与其它结节进行鉴别.方法:搜集行Gd-DTPA动态增强磁共振检查的RN病例共30例,全部病例均经手术切除病理或穿刺活检证实.MRI均行平扫、动态增强及延迟增强扫描,分析结节的信号特征及动态增强曲线.结果:肝再生性结节包括弥漫分布的小结节18例(铁质沉着性结节6例和非铁质沉着性结节12例)和大结节12例17个病灶.铁质沉着性结节在增强各期均无强化,时间-信号强度曲线较平直;大部分非铁质沉着性结节在T1WI上和T2WI上均为中等信号,周围纤维间隔为偏低信号,动态及延迟增强扫描结节轻度强化,时间-信号强度曲线与正常肝组织类似.本组所选大结节为直径大于0.5 cm、T1WI高信号、T2WI低信号的病灶,其中10个病灶(占58.8%)在T1W/WATS上信号高于T1W/IP.动态增强各期病灶无明显强化,时间-信号强度曲线显示病灶的曲线为缓慢上升型.结论:肝再生性结节有不同类型及表现形式,其中孤立的大结节型RN需与肝内其它结节鉴别.     

MRI多序列扫描技术在乳腺良恶性肿瘤诊断中的应用

目的 探讨磁共振多种检查序列和动态增强技术在乳腺检查中的应用价值.方法 对62例乳腺肿块病灶分别行常规横断位平扫:SE T1WI序列、脂肪抑制FSE T2WI序列、脂肪抑制T1WI SPGR(扰相梯度回波)序列;注射 Gd-DTPA后使用SPGR序列动态增强扫描.比较分析增强前后病灶的形态学特征,强化速率和强化峰值出现时间,时间-信号强度曲线(STC)的类型.结果 良性病变38例,恶性肿瘤24例.良性病变信号均匀35例, T1WI多为等低信号,T2WI为稍高信号或高亮信号.动态增强后绘制病灶感兴趣区的时间-信号强度曲线以无强化型28例、缓慢上升型9例.恶性病变信号不均23例,T1WI多呈低信号,T2WI为高和低信号混杂存在,动态增强后病灶时间-信号强度曲线快进快出型22例、快进平台型1例、快进慢升型1例.结论 MRI多序列及动态增强扫描技术对鉴别乳腺良恶性病变有重要价值.     

Dynamic contrast-enhanced MRI of benign prostatic hyperplasia and prostatic carcinoma: correlation with angiogenesis

AIM: To investigate the diagnostic and differential diagnostic values of dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) in prostatic diseases, and to investigate the correlation between the parameters of SI-T curves and angiogenesis. MATERIALS AND METHODS: Twenty-one patients with proven prostatic carcinoma (Pca) and 29 patients with proven benign prostatic hyperplasia (BPH) were examined using DCE MRI. Diagnostic characteristics for differentiation were examined using threshold values for maximum peak time, enhancement degree, and enhancement rate. Then, the signal intensity-time curves (SI-T curves) were analysed, and the correlations between the parameters of SI-T curves and the expression levels of vascular endothelial growth factor (VEGF) and microvascular density (MVD) were investigated. All patents underwent prostatectomy. DCE MRI and histological findings were correlated. RESULTS: Pca showed stronger enhancement with an earlier peak time, higher enhancement, and enhancement rate (p<0.05). Regarding the type of SI-T curves, in the BPH group six were type A, 10 were type B, and 13 were type C, whereas in the Pca group, 14 were type A, six were type B, and only one was type C (Chi-square test, chi2=13.57, P<0.005). The VEGF and MVD expression levels of Pca were higher than those of BPH. Peak time was negatively correlated with the expression levels of VEGF and MVD, whereas the enhancement degree and enhancement rate showed positive correlations (Pearson correlation, p<0.05). CONCLUSION: Based on T2-weighted imaging, DCE MRI curves can help to differentiate benign from malignant prostate tissue. In the present study the type C curve was rarely seen with malignant disease, but these results need confirmation.     

The value of dynamic MRI studies in parotid tumors

RATIONALE AND OBJECTIVES: To evaluate the ability of dynamic contrast-enhanced magnetic resonance imaging (MRI) to differentiate several tumor entities of the parotid gland in a prospective clinical trial. MATERIALS AND METHODS: A total of 112 patients with parotid tumors were examined with dynamic contrast-enhanced 1.5 T MRI. Precontrast axial T1-weighted imaging was used to select five slices for the dynamic study. Subsequently, a T1-weighted FLASH sequence was used for the dynamic contrast study (0.2 ml Gd/kg x body weight). Contrast agent application and the FLASH sequence were started simultaneously. Ten acquisitions of 10 seconds' scan time each were performed (total acquisition time 1:40 minutes). Signal intensity versus time (SIvT) curves was obtained for all tumors. After correlation of the categorized SIvT curves, these were compared with histopathology. Finally, all MRIs together with the tumor specific SIvT curves were re-read and correlated with histopathologic diagnosis. All reading sessions were done by three experienced radiologists. RESULTS: Four characteristic intensity-time curves were observed: pleomorphic adenoma showed a gradual increase in signal intensity, followed by a plateau phase on a low intensity level. Cysts showed a vacillating course at a low signal intensity level. Adenolymphomas as well as carcinomas showed a rapid increase in signal intensity followed by a plateau phase. Statistic significance was found for the time-to-peak values for adenolymphomas and pleomorphic adenomas and for the maximum peak signal intensity values for carcinomas. Together with other morphologic MRI criteria (contrast enhancement, border characteristics) and clinical features, a differentiation between adenolymphoma and carcinoma was possible. CONCLUSIONS: With additional dynamic contrast-enhanced MRI, a more reliable differentiation between common parotid tumors is possible before surgery.     

MRI在鼻咽癌肿瘤分期中的价值

目的 :探讨MRI在鼻咽癌 (NPC)肿瘤分期中的价值。方法 :回顾性分析了 2 4 0例经病理证实的NPC ,MRI平扫后增强扫描并加扫冠状扫描和矢状面。结果 :依NPC浸润方式分为内外、前后、上下 6个方向对肿瘤行MRI分期 :T1期 (向内 ) :肿瘤局限在鼻咽壁 2 5例 ;T2期 (向外和向后 )侵及咽旁浅间隙 80例 ,侵及咽旁深间隙 37例 ,侵及咽后间隙 2 6例 ;T3期 (向前和向下 )侵及鼻腔、上颌窦、蝶窦和口咽 4 4例 ;T4期 (向上侵及颅底、颅内 ) 2 8例。结论 :MRI有助于鼻咽癌的诊断和准确肿瘤分期。     

鼻咽缝间隙的解剖学基础及其影像学表现和意义

目的 在影像上提出鼻咽缝间隙的概念，介绍其CT和MRI表现及其意义。方法 正常CT组43例，正常MRI组36例，均进行鼻咽轴面平扫，其中加做鼻咽冠状面CT和MR扫描各5例，7例加做鼻咽后壁矢状面MR薄层扫描；2例鼻咽轴位断面标本作对照；鼻咽癌（NPC）组30例，同时进行CT与MR扫描，对鼻咽后软组织结构影像学表现进行详细观察分析。结果 鼻咽缝间隙位于椎前并列的头长肌或颈长肌之间，咽后壁后方，枕骨及颈椎前方，它包括上述肌肉之间的咽缝、咽后间隙、危险间隙、椎前间隙部分和组成这些间隙的筋膜，以及其中的纤维结缔组织、脂肪和淋巴结等结构，在CT上表现为三角形不均匀低密度影，在MRI上，呈三角形不均匀高信号影，其正中有粗细不一的低信号咽缝。正常CT组43例均在椎前肌之间出现1个层面以上的、呈低密度的两侧对称的三角形影，为鼻咽缝间隙；在斜坡和硬腭水平之间均见鼻咽缝间隙者22例，部分层面显示鼻咽缝间隙者14例，鼻咽缝间隙达口咽水平者7例。正常MRI组36例，在轴面像上35例在椎前肌之间可见两侧对称的呈不均匀高信号的三角形鼻咽缝间隙；从斜坡至硬腭水平均见鼻咽缝间隙者13例，部分可见11例，鼻咽缝间隙达口咽水平者11例；矢状面像上，鼻咽缝间隙止于C2椎体上部者4例、下部者3例；冠状面像上，鼻咽缝间隙呈纵行条带状影2例，倒置梯形3例。2具鼻咽断面尸体标本均见鼻咽后壁后方并列的头长肌或颈长肌之间三角形疏松纤维结缔组织。NPC组30例中鼻咽缝间隙对称存在者14例，不对称性变窄1例，消失者15例。结论 鼻咽部椎前并列的头长肌或颈长肌之间的结构在CT和MRI上统称为鼻咽缝间隙是合适的；NPC患者的鼻咽缝间隙消失和不对称性变窄多提示肿瘤侵犯椎前肌，而对称存在时，肿瘤多位于鼻咽顶后壁浅层。     

Predicting survival and early clinical response to primary chemotherapy for patients with locally advanced breast cancer using DCE‐MRI

Purpose

To evaluate dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI) as a tool for early prediction of response to neoadjuvant chemotherapy (NAC) and 5‐year survival in patients with locally advanced breast cancer.

Materials and Methods

DCE‐MRI was performed in patients scheduled for NAC (n = 24) before and after the first treatment cycle. Clinical response was evaluated after completed NAC. Relative signal intensity (RSI) and area under the curve (AUC) were calculated from the DCE‐curves and compared to clinical treatment response. Kohonen and probabilistic neural network (KNN and PNN) analysis were used to predict 5‐year survival.

Results

RSI and AUC were reduced after only one cycle of NAC in patients with clinical treatment response (P = 0.02 and P = 0.08). The mean and 10th percentile RSI values before NAC were significantly lower in patients surviving more than 5 years compared to nonsurvivors (P = 0.05 and 0.02). This relationship was confirmed using KNN, which demonstrated that patients who remained alive clustered in separate regions from those that died. Calibration of contrast enhancement curves by PNN for patient survival at 5 years yielded sensitivity and specificity for training and testing ranging from 80%–92%.

Conclusion

DCE‐MRI in locally advanced breast cancer has the potential to predict 5‐year survival in a small patient cohort. In addition, changes in tumor vascularization after one cycle of NAC can be assessed. J. Magn. Reson. Imaging 2009;29:1300–1307. © 2009 Wiley‐Liss, Inc.     

MRI in recurrent nasopharyngeal carcinoma

In this study, we retrospectively reviewed the MRI features of recurrent nasopharyngeal carcinoma (NPC) in 72 patients who underwent MRI before and after gadolinium injection. Recurrent NPC exhibited a high degree of regional spread and a variety of signal intensities and contours. MRI showed a nasopharyngeal mass in 50 patients (69.4 %); other sites of involvement included the parapharyngeal space (44.4 %), nasal cavity (12.5 %), paranasal sinuses (27.8 %), oropharynx (4.2 %), orbit (8.3 %), infratemporal fossa (18.1 %), skull base (59.8 %), intracranial area (51.4 %) and regional lymph nodes (15.3 %). On T2-weighted images, the nasopharyngeal mass gave high signal in 9 of 50 cases (18 %), intermediate in 27 (54 %), mixed in 8 (16 %) and low signal in 6 (12 %). Contrast enhancement was strong in 12 cases (24 %), moderate in 29 (58 %) and heterogeneous in 9 (18 %). The lesion was convex in 31 cases (62 %) and concave or straight in 19 (38 %). Recognition of the distribution and the appearance of recurrent NPC on MRI is essential for timely diagnosis and appropriate treatment. Received: 20 August 1998 Accepted: 2 February 1999