Comparison of contrast-enhanced magnetization transfer imaging and contrast-enhanced fat saturation T1-weighted imaging in nasopharyngeal carcinoma

OBJECTIVE: The objective of this study was to evaluate the efficacy of contrast-enhanced magnetization transfer (CEMT) imaging in the study of nasopharyngeal carcinoma (NPC). METHODS: The contrast-to-noise ratio (CNR) of CEMT images was compared with the CNR of contrast-enhanced fat-saturation (CEFS) T1-weighted images in locoregional tumors and adenopathies of 50 patients with pathologically proven NPC. RESULTS: The CEMT images showed higher CNRs than CEFS images of local nasopharyngeal regions. The mean CNRs of the precontrast T1-weighted, CEFS, and CEMT images were 4.9, 15.4, and 21.2, respectively. There was a statistically significant difference (p < 0.01) in the CNRs of CEFS and CEMT images. In considering images of nodal metastasis, the mean values in these three groups were 0.7, 16.8, and 19.7, respectively, with the difference (p < 0.05) between CEFS and CEMT being statistically significant. CONCLUSIONS: The CEMT image with a larger CNR is superior to the CEFS image in detecting locoregional NPC. CEMT can be useful in imaging patients with possible small tumors and local recurrences.     

3.0T动态对比增强MRI对前列腺癌与前列腺增生的鉴别价值

目的 探讨动态对比增强磁共振成像(DCE-MRI)半定量及定量参数对前列腺癌(PCa)与前列腺增生(BPH)的鉴别价值.方法 本研究经医院伦理委员会批准,回顾性分析于本院行DCE-MRI扫描,并经病理证实的PCa患者24例(69.79岁±8.21岁)、BPH患者22例(69.77岁±10.36岁).扫描序列包括横轴位T1WI、T2WI及DCE-MRI.测量PCa及BPH病变半定量值:MxSlp、washout、AUC90、AUC180;定量值:转运常数(Ktrans)、速率常数(Kep)及血管外细胞外容积比(Ve)值.使用独立样本f检验比较以上各值,使用受试者工作特征曲线(ROC)评估各值对PCa和BPH的鉴别效能.结果 PCa与BPH的MxSlp、washout、AUC90、AUC180值间差异均无统计学意义(29.76±83.58 vs 8.65±4.51、1.29±3.36 vs 0.14±0.37、14.96±5.76 vs 12.76±4.21、28.80±14.08 vs 26.13±8.40),P值分别为0.243、0.117、0.150、0.443.PCa的Ktrans及Kep值均高于BPH[(0.36±0.11) min-1vs(0.24±0.11)min-1、(1.93±0.89) min-1vs (1.20±0.57) min-1)],P值分别为0.001、0.002.PCa与BPH的Ve值间差异无统计学意义(0.23±0.11 vs 0.25士0.18),P值为0.604.Ktrans及Kep值诊断PCa的曲线下面积(AUC)分别为0.813、0.737,当Ktrans值≥0.273 min-1,Kep值≥1.595 min-1时诊断PCa的灵敏度和特异度分别为79.2％和82.7％、62.5％和86.4％.结论 DCE-MRI可为PCa与BPH鉴别提供较可靠的定量值.     

鼻咽癌磁共振灌注定量参数及ADC值与T分期的关系

目的：探讨鼻咽癌（NPC）磁共振灌注成像（PWI）定量参数及扩散加权成像（DWI）参数ADC 值与T 分期之间的相关性。方法：对94例NPC初治患者行PWI、DWI和T分期,分析PWI参数及ADC值与T分期之间的相关性,比较高低T分期NPC之间各 MR参数值的差异。结果：T 分期分别与 Ktrans （r＝0．226,P＝0．029）和 Ve （r＝0．553,P＝0．000）呈正相关,与Kep呈负相关（r＝－0．350,P＝0．001）。未发现T 分期与 fPV（r＝－0．122,P＝0．240）及 ADC 值（r＝－0．056,P＝0．592）之间存在线性相关。Ktrans、Kep和 Ve 值在 Thigh组（T3和 T4期 NPC）分别为（0．386±0．171）、（1．333±0．436）min－1和（0．302±0．107）,在 Tlow组（T1和 T2期 NPC）分别为（0．313±0．115）min－1、（1．552±0．472）min－1和0．219±0．102,两组间的差异有统计学意义。fPV和ADC值在Thigh组分别为（0．017±0．021）和（0．935±0．144）×10－3 s／mm2,在Tlow组分别为（0．019±0．018）和（0．950±0．196）×10－3 s／mm2,两组间的差异无统计学意义。与Ktrans和Kep值相比,Ve 值在判别Thigh组和Tlow组上诊断效能最大,其敏感性为91．8％、特异性为63．2％。结论：PWI定量参数可以反映不同T分期NPC在内部微循环灌注上的差异,而ADC值难以区分不同T分期NPC之间在水分子扩散方面的差别。     

MRI differentiation of recurrent nasopharyngeal carcinoma from postradiation fibrosis

A prospective study was performed to determine the usefulness of magnetic imaging (MRI) in differentiating local recurrence versus post-irradiation fibrosis in 72 patients after radiotherapy of nasopharyngeal carcinoma (NPC). All patients had a soft-tissue mass in the nasopharynx demonstrated by computed tomography. A total of 29 patients had tumor recurrence; 40 patients had only radiation fibrosis; 1 patient had postradiation edema and 2 patients had inflammatory changes. Based on the differences in signal intensity on T2-weighted Images, MRI may be promising as a noninvasive method for differentlating radiation fibrosis from local recurrent NPC. However, the signal intensity pattern of the tumor is not specific and may be seen in radiation edema and infection.     

Differentiation between the effects of T1 and T2* shortening in contrast-enhanced MRI of the breast

The purpose of this study is to describe a technique for magnetic resonance imaging (MRI) that can potentially improve identification of malignant tissue in the human breast. The suggested MRI technique is based on the differentiation between two competing effects leading to opposite changes in image intensity, namely, T1 and T2* shortening caused by administration of gadolinium chelate. The proposed approach also allows calculation of changes in the R2* relaxation rate in breast tissue. The feasibility of the technique for in vivo MRI and increased lesion contrast is demonstrated. The results indicate that this technique may improve detection of malignant breast tissue.     

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...     

Evaluation of dynamic contrast-enhanced T1-weighted perfusion MRI in the differentiation of tumor recurrence from radiation necrosis

Introduction

To investigate if perfusion measured with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) can be used to differentiate radiation necrosis from tumor recurrence in patients with high-grade glioma.

Methods

The study was approved by the institutional review board and informed consent was obtained from all subjects. 19 patients were recruited following surgery and radiation therapy for glioma. Patients had contrast enhancing lesions, which during the standard MRI examination could not be exclusively determined as recurrence or radiation necrosis. DCE-MRI was used to measure cerebral blood volume (CBV), blood–brain barrier (BBB) permeability and cerebral blood flow (CBF). Subjects also underwent FDG-PET and lesions were classified as either metabolically active or inactive. Follow-up clinical MRI and lesion histology in case of additional tissue resection was used to determine whether lesions were regressing or progressing.

Results

Fourteen enhancing lesions could be classified as progressing (11) or regressing (three). An empirical threshold of 2.0 ml/100 g for CBV allowed detection of regressing lesions with a sensitivity of 100 % and specificity of 100 %. FDG-PET and DCE-MRI agreed in classification of tumor status in 13 out of the 16 cases where an FDG-PET classification was obtained. In two of the remaining three patients, MRI follow-up and histology was available and both indicated that the DCE-MRI answer was correct.

Conclusion

CBV measurements using DCE-MRI may predict the status of contrast enhancing lesions and give results very similar to FDG-PET with regards to differentiation between tumor recurrence and radiation necrosis.     

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.     

局部复发鼻咽癌的MRI诊断及临床意义

目的:探讨局部复发鼻咽癌(LRNPC)的MRI表现特征及其临床意义.方法:回顾性分析86例LRNPC患者的MRI资料,其中47例经病理确诊,39例无组织学证据.根据系列MRI及临床诊治确诊.结果:①复发部位:鼻咽部40例(46.5%),鼻咽部以外46例(53.5%).多部位受累67例(78%),39例(45.3%)完全...     

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     

MRI of local disease in nasopharyngeal carcinoma: tumour extent vs tumour stage

The purpose was to use MRI to study in detail local tumour extension in patients presenting with nasopharyngeal carcinoma (NPC) and to compare the extent of local disease with the current T-stage classification. MR images of 150 patients with newly diagnosed nasopharyngeal carcinoma were obtained on a 1.5 T unit. 10 extranasopharyngeal sites were analysed for tumour involvement. The number of concurrently involved sites was determined. The extent of tumour invasion was compared with staging as defined by the fifth edition of the AJCC classification. The T-stage distribution was T1 21%, T2 16%, T3 41% and T4 22%. The frequencies of tumour invasion into an individual site, and the mean number of other concurrently involved sites were as follows: skull base 63%, 3.9 sites; parapharyngeal 56%, 3.9 sites; nasal cavity 53%, 4.0 sites; oropharyngeal 17%, 5.2 sites; sphenoid sinus 27%, 5.6 sites; cranium 21%, 5.7 sites; infratemporal fossa 2%, 6.3 sites; ethmoid sinus 14%, 6.5 sites; orbit 5%, 7.0 sites; maxillary sinus 5%, 7.1 sites; and hypopharynx 0%, 0 sites. Extranasopharyngeal extension commonly occurred superiorly into the skull base rather than inferiorly to the oropharynx (p < 0.0001). Anatomical sites defined within the same T-stage category had different frequencies of involvement and different frequencies of concurrently involved sites. Oropharyngeal involvement (T2 stage) was associated with a number of concurrently involved sites comparable to structures in the T3 category. Maxillary and ethmoid sinus involvement (T3 stage) were associated with a number of involved sites comparable to the T4 stage. Invasion of the maxillary antrum and orbit are markers of the most bulky form of NPC.     

Detection of prostate carcinomas with T1-weighted dynamic contrast-enhanced MRI. Value of two-compartment model

AIM: The suitability of dynamic parameters of the two-compartment model for detecting prostate carcinomas and its correlation with tumor microvascular density were evaluated. METHODS: The study included 43 patients with biopsy-proven prostate carcinoma: 28 were examined by 1.0-T MRI (Turbo-FLASH) and 15 by 1.5-T MRI (FLASH) with infusion of 0.1 mmol/kg Gd-DTPA. Signal time curves were parametrized with an open two-compartment model in amplitude and exchange rate constants (k(ep)).The microvascular density of resected prostate carcinomas was determined. RESULTS: The microvascular density in the tumors was significantly higher than in the adjacent healthy prostate tissue and correlated in both sequences with k(ep). Prostate carcinomas of the peripheral zone were demarcated by amplitude and k(ep). In the Turbo-FLASH sequence there was a significant difference between the tumor tissue and healthy peripheral zone in terms of k(ep) and in the FLASH sequence in terms of amplitude. CONCLUSION: Prostate carcinomas can be visualized with dynamic T1-weighted MR sequences using a two-compartment model. Moreover, the parameter k(ep) reveals the microvascular density in the tumor and can thus provide valuable clinical information for characterizing the tumors.     

Dynamic contrast-enhanced MRI in the differentiation of posttreatment fibrosis from recurrent carcinoma of the head and neck

OBJECTIVE: The aim of this study was to investigate the value of dynamic contrast-enhanced magnetic resonance imaging (MRI) in the differentiation of posttreatment fibrosis from recurrent carcinoma, by comparing the dynamic contrast-enhancement characteristics of the lesions. MATERIALS AND METHODS: Twenty-six patients with previously treated carcinoma of the head and neck are studied by conventional and dynamic contrast-enhanced MRI at least 6 months after treatment by radiotherapy and/or surgery. Patients are divided into tumor-positive or -negative groups according to the radiological and clinical follow-up and biopsy. Lesion enhancement ratios at each dynamic sequence are calculated. RESULTS: The tumor-positive group consisted of 11 patients, while the tumor-negative group included 15 patients. Between the two groups, lesion enhancement ratios are found to be significantly different (P<.05). CONCLUSION: Dynamic contrast-enhanced MRI may be a valuable modality in the differentiation of recurrent tumor from posttreatment fibrotic changes of the head and neck.     

动态增强MRI时间信号强度曲线在卵巢良恶性肿瘤鉴别中的价值

目的探讨动态增强MRI时间信号强度曲线(TIC)鉴别卵巢肿瘤良恶性的价值。方法收集2016年1月—2017年8月间于我院超声检查发现盆腔附件肿块的71例女性病人,年龄14～78岁,中位年龄52岁。所有病人行MRI常规及动态增强检查后经手术获得病理结果。利用工作站在肿块实性区和正常子宫外肌层设置兴趣区获取TIC,以子宫外肌层强化曲线为基准,对卵巢肿块实性区的TIC类型进行校正,分析曲线类型与良恶性卵巢肿瘤的关系。采用χ~2检验比较良恶性肿瘤间3种TIC类型差异。结果 71例病人中包括卵巢恶性肿瘤40例,良性肿瘤26例,交界性肿瘤5例。上述3种肿瘤的TIC类型的差异有统计学意义(P0.05)。良性肿瘤以Ⅰ型TIC为主(73.1%),恶性肿瘤以Ⅲ型TIC为主(77.5%)。MRI+TIC鉴别肿瘤良恶性的敏感度、特异度、阳性预测值和阴性预测值较单独常规MRI检查各指标均有不同程度提高。结论动态增强MRI及其TIC对卵巢良恶性肿瘤具有重要的鉴别诊断价值。     

MRI and CT of nasopharyngeal carcinoma

OBJECTIVE: This article reviews the MRI and CT of nasopharyngeal carcinoma. Extension of nasopharyngeal tumors, especially into the skull base and the deep facial spaces, is well illustrated on imaging. Assessment of retropharyngeal and cervical lymphadenopathy is important for treatment planning. MRI is commonly used for monitoring patients after therapy. CONCLUSION: Imaging can detect effect of radiation on surrounding structures. The imaging findings that help to differentiate nasopharyngeal carcinoma from simulating lesions are discussed.     

Histological differentiation grade and microvascular invasion of hepatocellular carcinoma predicted by dynamic contrast-enhanced MRI

Purpose:

To explore the potential use of magnetic resonance imaging (MRI) in predicting the outcome for patients with hepatocellular carcinoma (HCC), imaging characteristics were correlated with pathological findings and clinical outcome.

Materials and Methods:

With permission from the Ethical Board, clinical data and tissues of resected HCC patients were collected, including the preoperative MRI. The role of MRI characteristics on recurrence and survival were evaluated with univariate and multivariate analyses.

Results:

Between January 2000 and December 2008, 87 patients with 104 HCCs were operated on. Microvascular invasion was present in 55 lesions (53%). HCC was characterized as well differentiated in 15 lesions (14%), as moderate in 50 lesions (48%), and as poorly differentiated in 34 lesions (33%). Due to preoperative treatment in five lesions (5%) no vital tumor was left. In 85 lesions (88%) washout of contrast was noted. Of the 87 patients, 28 (32%) with 37 lesions developed HCC recurrence; these patients had microvascular invasion significantly more often and a moderate or poorly differentiated tumor (P < 0.001 and P = 0.025, respectively). MRI more often showed washout when HCC was moderately or poorly differentiated (P < 0.001) or microvascular invasion was present (P = 0.032).

Conclusion:

Differentiation grade and microvascular invasion are significantly associated with the presence of washout demonstrated on dynamic contrast‐enhanced MRI. J. Magn. Reson. Imaging 2012;36:641–647. © 2012 Wiley Periodicals, Inc.     

MR增强扫描在鼻咽癌放疗后放射性脑损伤中的诊断价值

目的:探讨鼻咽癌放疗后颞叶放射性脑损伤的MR增强扫描表现特点及诊断价值。方法:回顾性分析36例鼻咽癌放疗后颞叶放射性脑损伤患者的临床及MR影像资料。按病变的主要发病部位及MR表现将其分为灰质型及白质型,其中白质型进一步分为白质型Ⅰ期和白质型Ⅱ期。结果:36例放射性脑损伤包括27例白质型及9例灰质型,其中27例白质型包括白质型Ⅰ期18例、白质型Ⅱ期9例。白质型Ⅰ期病例中增强扫描均表现为颞叶底部灰质内为主团块状或散在的斑点状、斑片状实质强化,强化区多位于颞叶底部内侧灰质及颞极区灰质;白质型Ⅱ期病例增强扫描主要表现为花环状强化,占强化病灶的56%,其它主要表现为坏死灶周边及颞叶底部灰质内不规则实质强化。灰质型病例中增强扫描表现为病变区斑点状或结节状强化。结论:鼻咽癌放疗后颞叶放射性脑损伤的强化部位、强化形状及强化范围均具有一定的特征性,增强扫描在放射性脑损伤的诊断及早期征象的发现中有重要价值,应作为常规扫描进行。     

Fat-saturated contrast-enhanced T1-weighted MRI in evaluation of osteosarcoma and ewing sarcoma

To assess contrast-enhanced (C+), fat-saturated (FatSat), T1-weighted (T1W) imaging in the characterization of the soft tissue mass associated with primary bone tumors, we compared it with T2-weighted (T2W) imaging in patients with osteosarcoma (n = 36) and Ewing sarcoma family of tumors (Ewing sarcoma; n = 11). Periosseous tumor compared with normal muscle had greater contrast-to-noise ratio (CNR) on the FatSat T1W C+ image than on T2W for 81% (38/47; P < .0001) of patients. The CNR of periosseous tumor compared with subcutaneous fat was greater on FatSat T1W C+ for 98% (46/47; P < .0001). Radiologists found it easier to evaluate neurovascular bundle proximity to tumor with FatSat T1W C+ images than with T2W for 64% of patients (30/47; P < .0001). They judged FatSat T1W C+ superior to T2W for periosseous tumor conspicuity and visualization of soft tissue necrosis in 62% (29/47; P < .0001). In patients with osteosarcoma or Ewing sarcoma, FatSat T1W C+ imaging may replace T2W imaging for soft tissue mass evaluation, especially if contrast is being used for dynamic enhancement.