外周恶性神经鞘膜瘤的影像学表现

目的:总结分析外周恶性神经鞘膜瘤的影像学表现,提高鉴别诊断能力。方法:回顾性分析11例经手术或病理证实的恶性神经鞘膜瘤的影像学表现,并与手术病理对照分析,11例中行CT检查3例,行MRI检查4例,CT和MRI均检查4例。结果:CT平扫表现为等、低混合密度软组织肿块影,形态不规则,病灶边缘较光整2例,边缘毛糙5例。CT增强扫描呈不均匀强化,坏死区不强化,网格样强化2例,不均匀强化5例。T1WI呈等、略低信号,内见局灶性长T1信号影;T2WI序列以略高信号为主,内见局灶性长T2信号,周围软组织见片状浸润高信号;MRI增强扫描呈不均匀强化。结论:恶性外周神经鞘膜瘤的CT和MRI表现具有一定的特征性。     

Magnetic resonance appearance of peripheral nerve sheath tumors

Magnetic resonance imaging (MRI) was used to evaluate 22 histologically proven peripheral nerve sheath tumors, approximately two-thirds of which arose in the lower extremity. The histologic distribution was as follows: 12 schwannomas, 7 neurofibromas, and 3 malignant peripheral nerve sheath tumors (2 of which occurred in patients with neurofibromatosis). Most lesions demonstrated an intermediate to moderately bright signal on T₁-weighted images and were minimally inhomogeneous. All lesions were moderately bright on proton-density-weighted images and bright on T₂-weighted images, again with variable inhomogeneity. The extent of the tumor was best assessed on proton-density- and T₂-weighted images. Smooth margins were noted in 19 lesions. Of the 3 remaining lesions, 2 were malignant (but had been subjected to biopsy prior to MRI), and the other lesion was a plexiform neurofibroma. MRI accurately determined the relationship between the lesion and the adjacent neurovascular structures and muscles, thereby assisting surgical management. On MRI, 5 lesions demonstrated coexistent subtle muscle atrophy along the longitudinal axis of surrounding or distally innervated musculature. This latter finding, together with the presence of a tumor in the vicinity of a large nerve trunk, suggests a peripheral nerve sheath neoplasm.The opinions and assertions contained herein are the private views of the authors and do not reflect the views of the Uniformed Services University of the Health Sciences, the Department of the Army, or of the Department of Defense     

软组织神经鞘肿瘤的MRI诊断

目的 评价MR平扫及动态增强扫描对软组织神经鞘肿瘤的诊断价值。方法 回顾分析23例30个经病理证实软组织神经鞘肿瘤的MRI特征，其中15个良性神经鞘肿瘤，包括许旺瘤（神经鞘膜瘤）13个（12例），神经纤维瘤2个（2例）；15个为恶性外周神经鞘肿瘤。23例均行常规MR扫描，包括自旋回波（SE）T1WI，快速自旋回波（FSE）T2WI以及快速多平面扰相梯度回波序列（FMPSPGR）平扫和动态增强扫描。结果 （1）23例患者共30个病灶，软组织神经鞘肿瘤表现为梭形（15个），靶征（9个），神经出入征（10个），脂肪分离征（10个）；2个（2例）恶性神经鞘膜肿瘤显示周围水肿。（2）12个良性神经鞘肿瘤中9个表现为延迟强化，3个无明显强化或轻度强化；所有15个恶性外周神经鞘肿瘤及3个良性神经鞘肿瘤表现为第1期明显或中度强化，第2期和第3期持续强化或强化程度稍有下降。结论 梭形肿块、靶征、与神经关系密切及脂肪分离征是软组织神经鞘肿瘤较特征性的表现，而肿瘤的MR动态增强强化方式和周围有无水肿对神经鞘肿瘤良、恶性鉴别有一定价值。     

Gadolinium-DTPA enhancement of soft tissue tumors in magnetic resonance imaging—preliminary clinical experience in five patients

In a preliminary report of a clinical trial of gadolinium-DTPA (Gd-DTPA) for enhancement of soft tissue tumors in magnetic resonance imaging (MRI), experience of the first five cases is presented. Enhancement was found to give better delineation of the tumor in richly vascularized parts of the tumors, compressed tissue immediately surrounding the tumor, and in atrophic, but richly vascularized, muscle.     

Magnetic resonance imaging of benign soft tissue neoplasms in adults

This article reviews a spectrum of benign soft tissue tumors found in adults. Rather than presenting a complete review, the focus of this article is on benign tumors for which the diagnosis may be confidently made or strongly suggested on the basis of imaging. Diagnoses presented include nodular fasciitis, superficial and deep fibromatosis, elastofibroma, lipomatous lesions, giant cell tumor of the tendon sheath, pigmented villonodular synovitis, peripheral nerve sheath tumors, Morton neuroma, hemangioma, and myxoma.     

CT of malignant peripheral nerve sheath tumor

Malignant peripheral nerve sheath tumors are soft tissue sarcomas that typically arise from a neurofibroma. Patients with neurofibromatosis type 1 represent approximately half of the population diagnosed with these tumors. This autosomal-dominant genetic disorder is distinguished by loss-of-function mutations in the neurofibromin 1 gene, which ultimately promotes atypical cellular proliferation. These biologically aggressive tumors are associated with a poor prognosis as they are resistant to available therapies and have high rates of recurrence, progression, and mortality. In this article, we report the case of a 45-year-old male with a history of neurofibromatosis type 1 who was diagnosed with a malignant peripheral nerve sheath tumor. We focus on optimizing diagnosis and treatment through the application of radiological imaging modalities, including cinematic rendering.     

骨肿瘤的MR灌注和扩散加权成像研究

目的对临床常见的骨肿瘤进行MR灌注成像(PWI)和扩散加权成像(DWI)研究,探讨其在骨肿瘤定性诊断中的价值。方法收集恶性骨肿瘤18例,良性骨肿瘤21例,行MR PWI和MR DWI,应用Functool2软件分析,于灌注像上得到病灶时间-信号曲线(TIC)、首过期(FP)信号递减幅度、TIC最大线性斜率、两次稳态信号差值;于DWI上获得病灶表观扩散系数(ADC)值;采用SPSS13.0统计分析软件,将从良、恶性骨肿瘤两组样本中获得的各种参数用成组设计的两样本均数进行t检验,采用受试者操作特征(ROC)曲线选择良恶性肿瘤鉴别诊断的阈值,计算MR PWI和MR DWI诊断恶性骨肿瘤的敏感度、特异度、和准确度。结果MR PWI显示,17/21的良性骨肿瘤TIC表现为I型(平稳型)及II型(缓降缓升型),恶性骨肿瘤TIC表现为III型和IV型(速降型);良、恶性骨肿瘤之间的FP信号递减幅度、TIC最大线性斜率及两次稳态信号差值在良、恶性骨肿瘤之间的差异均具有显著性统计学意义,其据此诊断恶性骨肿瘤的准确度分别为82.1%、79.5%和87.2%;有4例良性骨肿瘤可根据其MR-PWI作定性判断,结果误诊为恶性肿瘤。MR DWI显示:b=300s/mm2时,良、恶性骨肿瘤的ADC值的差异具有统计学意义;若以ADC1.63×10-3mm2/s为恶性阈值,其诊断恶性骨肿瘤的准确度为79.5%。MR PWI和MR DWI诊断恶性骨肿瘤的准确度分别为89.7%和79.5%。结论MR PWI比MR DWI更有助于鉴别良、恶性骨肿瘤及肿瘤样病变,但恶性骨肿瘤与富血供良性骨肿瘤及肿瘤样病变的灌注参数存在重叠,此时结合MR DWI可以提高诊断准确度。     

Magnetic resonance imaging of malignant soft tissue neoplasms in the adult

This review addresses the spectrum of malignant soft tissue tumors frequently found in adults. Rather than presenting a complete review, the focus of this discussion is on common lesions or lesions in which the diagnosis may be suggested on the basis of imaging. Diagnoses covered include undifferentiated high-grade pleomorphic sarcoma, fibrosarcoma, dermatofibrosarcoma protuberans, liposarcoma, synovial sarcoma, malignant peripheral nerve sheath tumor, clear cell sarcoma, hemangioendothelioma, hemangiopericytoma, angiosarcoma, and leiomyosarcoma.     

Intraosseous malignant peripheral nerve sheath tumor in a patient with neurofibromatosis

Malignant peripheral nerve sheath tumors (MPNSTs) are uncommon sarcomas that almost always arise in soft tissue. They can develop in pre-existing neurofibromas or schwannomas, de novo from peripheral nerves, or following radiation therapy. Primary intraosseous MPNST is rare and has been reported most frequently in the mandible. Of the reported cases involving the long bones, none has been associated with neurofibromatosis type 1 (NF-1). We report a case of MPNST arising in the femur in a patient with NF-1.     

Low field (0.02 T) magnetic resonance imaging of bone and soft tissue tumors

Extremely low field magnetic resonance imaging (MRI) was evaluated in 16 patients with bone and soft tissue tumors, both benign and malignant. Twelve of the lesions were located in the lower extremity, 2 in the gluteal and 2 in the shoulder region. The findings were compared to the results of computed tomography (CT). Low signal-to-noise ratio and poor spatial resolution result in an image quality which is inferior to that obtained with MR imaging at higher field strengths. In spite of this, the diagnostic information seems to be at least comparable to that obtained from CT.     

Intraosseous malignant peripheral nerve sheath tumor with local recurrence,lung metastases and death

Malignant peripheral nerve sheath tumor (MPNST) is almost always seen in soft tissue. Skeletal involvement by MPNST is uncommon and usually results from secondary invasion. Primary MPNSTs are exceptionally rare. We report a surgically proven case of intraosseous MPNST, with local recurrence and lung metastasis during follow-up. The imaging and histological features of the case are described and the literature on the subject briefly reviewed.     

扩散加权成像对良恶性淋巴结鉴别的研究进展

淋巴结转移与否对于癌症病人的预后、分期及治疗方案的选择极为重要。目前常规MRI依靠淋巴结大小鉴别其良恶性的准确性不高，利用MR功能成像方法鉴别淋巴结良恶性是目前影像学研究的热点。其中扩散加权成像相较其他方法具有诸多优点。近年来非高斯模型包括双指数模型、拉伸指数模型、扩散峰度模型等逐渐应用于临床。现就传统及非高斯模型扩散加权成像在淋巴结良恶性鉴别上的研究现状及价值予以综述。     

磁共振在眼球常见恶性肿瘤诊断中的价值

目的通过分析眼球常见恶性肿瘤的磁共振影像学表现特征,以提高对眼球恶性肿瘤的认识。方法回顾分析经手术病理及临床证实27例眼球恶性肿瘤病例的磁共振影像表现。结果总计眼球恶性肿瘤27例,其中葡萄膜黑色素瘤19例,表现为突向眼球内结节状、蘑菇状影,多数T₁WI呈高信号、T₂WI呈低信号,增强后病灶轻度或中度强化;葡萄膜黑色素细胞瘤恶变1例,表现为突向眼球内结节状影,T₁WI呈高信号、T₂WI呈低信号,增强后病灶中度强化;视网膜母细胞瘤4例,表现为眼球内突向玻璃体内肿块状影,T₁WI呈等信号、T₂WI呈等低信号,增强后病灶轻度或中度强化;脉络膜转移瘤2例,表现眼球后壁半球、扁平样突起影,T₁WI呈稍高信号,T₂WI呈稍低信号,增强后病灶中度强化,边缘强化明显。眼球内淋巴瘤1例,表现为眼内T₁WI信号增高,眼球内软组织结节影,T₁WI呈等信号、T₂WI呈等低信号,增强后病灶轻度强化。结论磁共振检查能够准确反映眼内常见恶性肿瘤的发生部位、大小及范围等影像特征,为临床治疗方法的选择提供重要的影像学依据。     

Differentiation of clinically benign and malignant breast lesions using diffusion-weighted imaging

PURPOSE: To evaluate the value of diffusion-weighted imaging (DWI) in distinguishing between benign and malignant breast lesions. MATERIALS AND METHODS: Fifty-two female subjects (mean age = 58 years, age range = 25-75 years) with histopathologically proven breast lesions underwent DWI of the breasts with a single-shot echo-planar imaging (EPI) sequence using large b values. The computed mean apparent diffusion coefficients (ADCs) of the breast lesions and cell density were then correlated. RESULTS: The ADCs varied substantially between benign breast lesions ((1.57 +/- 0.23) x 10(-3) mm(2)/second) and malignant breast lesions ((0.97 +/- 0.20) x 10(-3) mm(2)/second). In addition, the mean ADCs of the breast lesions correlated well with tumor cellularity (P < 0.01, r = -0.542). CONCLUSION: The ADC would be an effective parameter in distinguishing between malignant and benign breast lesions. Further, tumor cellularity has a significant influence on the ADCs obtained in both benign and malignant breast tumors.     

Orbital benign and malignant lymphoproliferative disorders: Differentiation using semi-quantitative and quantitative analysis of dynamic contrast-enhanced magnetic resonance imaging

ObjectivesTo assess the value of dynamic contrast-enhanced MR imaging (DCE-MRI) in differentiating benign from malignant orbital lymphoproliferative disorders (OLPDs).MethodsThirty-nine patients with orbital lymphoproliferative disorders (21 malignant and 18 benign) underwent DCE-MRI scan for pre-treatment evaluation from March 2013 to December 2015. Both semi-quantitative (TTP, AUC, Slope_max) and quantitative (K^trans, k_ep, v_e) parameters were calculated, and compared between two groups. Receiver operating characteristic (ROC) curve analyses were used to determine the diagnostic value of each significant parameter.ResultsMalignant OLPDs showed significantly higher k_ep, lower v_e, and lower AUC than benign OLPDs, while no significant differences were found on K^trans, TTP and Slope_max. ROC analyses indicated that v_e exhibited the best diagnostic performance in predicting malignant OLPDs (cutoff value, 0.211; area under the curve, 0.896; sensitivity, 76.2%; specificity, 94.9%), followed by k_ep (cutoff value, 0.853; area under the curve, 0.839; sensitivity, 85.7%; specificity, 89.9%).ConclusionDCE-MRI and specially its derived quantitative parameters of k_ep and v_e are promising metrics for differentiating malignant from benign OLPDs.     

Differentiation of benign and malignant ampullary obstructions on MR imaging

Objective

To define diagnostic criteria for differentiating malignant ampullary carcinoma from benign ampullary obstruction on MR imaging.

Materials and methods

Nineteen patients with ampullary carcinoma and 22 patients with benign ampullary obstruction were enrolled. At the first session, two radiologists independently evaluated specific imaging findings, and then reached consensus decisions. At the second session, another two radiologists, who were informed about useful differentiation criteria based on the results from the first session, reviewed images and determined the causes of ampullary obstruction. Sensitivity and specificity were calculated for each interpretation session, and the Cohen κ statistic was used to evaluate interobserver agreement.

Results

Findings of the presence of an ampullary mass (P < 0.001), papillary bulging (P < 0.001), irregular (P = 0.021) and asymmetric (P < 0.001) common bile duct (CBD) narrowing, and proportional biliary dilatation (P < 0.001) were more commonly seen in patients with an ampullary carcinoma. The sensitivity and specificity of the first session were 84.2% and 86.4% after consensus. The sensitivity increased to 100% for both the readers at the second session, while the specificity decreased to 63.6% and 59.1%, respectively.

Conclusions

Identification of an ampullary mass, papillary bulging, irregular and asymmetric narrowing of the CBD, or proportional biliary dilatation may improve the diagnosis of ampullary carcinoma in patients with ampullary obstruction.     

ADC平均值及最小值在鉴别良、恶性四肢软组织肿瘤中的价值

目的:探讨ADC平均值及最小值在鉴别四肢软组织肿瘤良恶性中的价值.方法:搜集经病理证实的53例四肢软组织肿瘤患者,其中良性24例,恶性29例,53例患者均行MRI及DWI检查,分别测量病灶的ADC平均值及ADC最小值.采用独立样本t检验比较良、恶性四肢软组织肿瘤的ADC平均值及ADC最小值差异;采用受试者工作特征(RO...     

Usefulness of diffusion-weighted imaging for differentiating between desmoid tumors and malignant soft tissue tumors

Purpose

To evaluate the usefulness of diffusion‐weighted imaging (DWI) for differentiating between desmoid tumors and malignant soft tissue tumors.

Materials and Methods

Conventional MRI and DWI were performed for 8 desmoid tumors and 74 malignant soft tissue tumors. DWI was obtained with a single‐shot echo‐planar imaging sequence using a 1.5 Tesla (T) MR imager. DW images were acquired with motion‐probing gradient pulses applied along three directions (x, y, and z axes) with three b‐factors (0, 500, and 1000 s/mm²). Two observers blinded to clinical information measured three regions of interest within the solid tumor and selected a minimum apparent diffusion coefficient () in each lesion. The mean ADC of desmoid tumors was calculated and compared with that of malignant soft tissue tumors using the Mann‐Whitney U test.

Results

The mean ADC of desmoid tumors and malignant soft tissue tumors was 1.36 ± 0.48 × 10⁻³ mm²/s and 0.88 ± 0.20 × 10⁻³ mm²/s (mean ± SD), respectively. The mean ADC of the desmoid tumors was significantly higher than that of malignant soft tissue tumors (P < 0.01).

Conclusion

DWI is considered to be useful for differentiating between desmoid tumors and malignant soft tissue tumors. In the future, further investigation in a large series is necessary. J. Magn. Reson. Imaging 2011;33:189–193. © 2010 Wiley‐Liss, Inc.

     

四肢神经鞘瘤脂肪分离征和神经出入征的观察分析

目的探讨四肢软组织神经鞘瘤MRI脂肪分离征和神经出入征的关系。方法回顾性分析2014年1月至2018年7月,浙江大学医学院附属第二医院141例经手术、病理证实的四肢软组织神经鞘瘤患者的MRI资料。根据手术所见肿瘤位置,将患者分为肌内、肌间组,对两组神经鞘瘤的脂肪分离征和神经出入征进行对照分析,并以χ2检验比较两组间两种征象的分布情况。结果141例患者共有152个病灶:肌内神经鞘瘤41个,肌间神经鞘瘤111个。肌内神经鞘瘤出现脂肪分离征48处、神经出入征14处,肌间神经鞘瘤出现脂肪分离征9处、神经出入征190处。统计结果显示,两组病灶的脂肪分离征(χ2=55.545,P<0.001)、神经出入征(χ2=26.969,P<0.001)差异均有统计学意义。结论脂肪分离征多出现在肌内神经鞘瘤,神经出入征多出现在肌间神经鞘瘤。     

Computed tomography and magnetic resonance imaging findings of soft tissue perineurioma

Soft tissue perineurioma is an uncommon benign peripheral nerve sheath tumor, although it is the most common subtype of perineuriomas. We present a case of soft tissue perineurioma in the left groin of a 48-year-old man. Precontrast computed tomography showed a homogeneous hypodense mass that showed faint enhancement. The mass appeared with hypointensity on T1-weighted magnetic resonance (MR) images and heterogeneous hyperintensity on T2-weighted MR images. Slight contrast uptake was noted on enhanced T1-weighted MR images with fat suppression. Although these CT and MR imaging findings were nonspecific, the overall imaging features are similar to those of schwannomas.