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。     

Nodular fasciitis: correlation of MRI findings and histopathology

OBJECTIVE: To compare the histopathology of nodular fasciitis (NF) with the magnetic resonance imaging (MRI) findings in order to evaluate the basis of the MR signal characteristics. DESIGN AND PATIENTS: Ten patients with NF, nine females and 1 male, with an age ranging from 13 to 58 years (mean 26.8 years) were studied. MRI findings, available in all 10 patients, were compared with the histopathology in nine patients, and an area-to-area comparative study of the whole specimen section histopathology and MRI was performed in two patients. RESULTS: On the basis of an excisional biopsy or resection specimen, the nine lesions were classified into myxoid ( n=4), cellular ( n=3) and fibrous ( n=2) subtypes. Four myxoid lesions with a subcutaneous location showed a homogeneous SI comparable with muscle on T1-weighted images, high SI on T2-weighted images, and had homogeneous enhancement. One cellular lesion presented with homogeneous, slightly higher SI than muscle on T1-weighted images and inhomogeneous, high SI on T2-weighted images. Alcian blue stain of the whole specimen section revealed the lesion had two parts corresponding to different enhancement patterns on MRI. The blue-stained myxoid part showed markedly diffuse enhancement, while the non-stained cystic space had only peripheral enhancement. Two other cellular lesions had the same appearance on both T1- and T2-weighted images and showed inhomogeneous, diffuse enhancement. One fibrous subtype lesion presented with inhomogeneous, overall slightly higher SI than muscle on T1-weighted images, lower SI at the periphery and high SI in the center on STIR images and only peripheral enhancement. Microscopy and CD-31 staining of the lesion showed more extracellular matrix, with poor vascularity in the center and more collagenous matrix with higher vascularity at the periphery. CONCLUSION: Although similar findings were found in some lesions, the large histologic variability of NF hampers the definition of a prototype of NF on MRI. However, the MRI appearance of the myxoid subtype is rather characteristic. Histologic findings reflect the different SI characteristics and enhancement pattern on MRI.     

The value of magnetic resonance imaging in the differentiation between malignant peripheral nerve-sheath tumors and non-neurogenic malignant soft-tissue tumors

Objective To assess the sensitivity and specificity of MRI criteria in the differentiation between malignant peripheral nerve sheath tumors (MPNST) and non-neurogenic malignant soft-tissue tumors (MSTT).Design and patients MRI examinations of 105 patients with pathologically proven malignant soft-tissue lesions (35 MPNST and 70 MSTT) were retrospectively reviewed, the reviewers being unaware of the pathological diagnosis. Using a standardized protocol, the tumors were evaluated for multiple parameters regarding morphology and appearance on different sequences before and after gadolinium contrast administration (location, distribution, delineation, homogeneity, size, shape, relationship to bone and neurovascular bundle, intralesional hemorrhage, necrosis, perilesional edema, lymphangitis and signal intensities). Results were compared using a chi-square or Fisher’s exact test.Results MRI findings suggestive of MPNST (p<0,05) were intermuscular distribution, location on the course of a large nerve, nodular morphology, and overall non-homogeneity on T1-weighted images, T2-weighted images and T1-weighted images after gadolinium contrast injection. MRI findings in favor of MSTT were intramuscular distribution, ill-delineated appearance of more than 20% of the lesion’s circumference, and presence of intralesional blood vessels, perilesional edema and lymphangitis. There is no significant difference for degree and pattern of enhancement after gadolinium contrast injection, nor for presence of bone involvement or cystic or necrotic areas.Conclusion MRI provides several features that contribute to the differentiation between MPNST and non-neurogenic malignant soft-tissue tumors. MRI findings suggestive of MPNST should be helpful to pathologists in the strategy for further examination.     

Schwannoma in neurofibromatosis type 1: a pitfall for detecting malignancy by metabolic imaging

Neurofibromatosis type 1 (NF1) is a neurocutaneous syndrome characterized by the development of multiple peripheral nerve sheath tumors, the majority of which are benign neurofibromas. However, malignant peripheral nerve sheath tumors (MPNSTs) occur with a 10 % lifetime risk in patients with NF1, often developing within a neurofibroma. When clinical suspicion for an MPNST arises, imaging with FDG PET and MRI is performed to characterize a peripheral tumor for potential malignancy. In this report, we describe a patient with NF-1 who had two peripheral tumors with similar features by PET, both suspicious for MPNST, but differing features by MRI, one of which was subsequently determined to be an MPNST and the second to be a schwannoma.     

四肢软组织平滑肌肉瘤的磁共振诊断

目的：探讨四肢软组织平滑肌肉瘤的MRI表现及其临床诊断价值。方法：回顾性分析10例经手术病理证实的四肢软组织平滑肌肉瘤的MRI表现。10例均行MRI平扫及增强扫描。结果：肿瘤位于浅筋膜深部8例,其中位于大腿4例,小腿3例,上臂1例;浅部病灶2例,其中位于肘关节周皮下1例,髂部皮下脂肪中1例。T1WI均以等信号为主,7例信号不均匀;T2WI以斑片状略高信号为主,9例信号不均匀。8例病灶内有坏死囊变区。5例病灶的少部分边缘可见假包膜。2例病灶内合并出血。2例瘤周有轻度水肿。增强后9例肿瘤实质呈中度不均匀斑片状强化,1例明显强化。结论：四肢平滑肌肉瘤的MRI表现缺乏特异性但在一定程度上能反映其恶性特点,对术前定性诊断及手术方案的制订有一定意义。     

Subdural enhancement on postoperative spinal MRI after resection of posterior cranial fossa tumours

In malignant brain tumours which may disseminate staging, usually by cranial and spinal MRI is necessary. If MRI is performed in the postoperative period pitfalls should be considered. Nonspecific subdural contrast enhancement on spinal staging MRI is rarely reported after resection of posterior fossa tumours, which may be mistaken for dissemination of malignancy. We investigated the frequency of spinal subdural enhancement after posterior cranial fossa neurosurgery in children. We reviewed 53 postoperative spinal MRI studies performed for staging of paediatric malignant brain tumours, mainly infratentorial primitive neuroectodermal tumours 2–40 days after surgery. There was contrast enhancement in the spinal subdural space in seven cases. This was not seen in any of eight patients who had been operated upon for a supratentorial tumour. After resection of 45 posterior cranial fossa tumours the frequency of subdural enhancement was 15.5%. MRI showing subdural enhancement was obtained up to 25 days postoperatively. No patient with subdural enhancement had cerebrospinal fluid (CSF) examinations positive for tumour cells or developed dissemination of disease in the CSF. Because the characteristic appearances of subdural contrast enhancement, appropriate interpretation is possible; diagnosis of neoplastic meningitis should rarely be impeded. Because of the striking similarity to that in patients with a low CSF-pressure syndrome and in view of the fact that only resection of tumours of the posterior cranial fossa, usually associated with obstructive hydrocephalus, was followed by this type of enhancement one might suggest that rapid changes in CSF pressure are implicated, rather the effects of blood introduced into the spinal canal at surgery.     

恶性外周神经鞘膜瘤的CT和MRI表现

目的回顾性分析恶性外周神经鞘膜瘤的CT和MRI表现,提高对该病的诊断准确性。方法搜集恶性外周神经鞘膜瘤病人12例,术前均进行了CT或MRI检查。结果CT表现平扫上为等、低密度混合的软组织肿块影,外形不规则,边界清楚(n=9)或模糊(n=3);增强扫描时呈不均性强化,坏死区不强化。MRI表现边界模糊,信号混杂。T1WI序列上多与肌肉等信号(n=11),内示局灶性长T1信号影;T2WI抑脂序列上以略高信号为主,边界清楚(n=2)或模糊(n=10),内示局灶性长T2信号,周围软组织浸润表现为片状高信号;增强扫描时呈不均性强化。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。     

MRI with mangafodipir trisodium in the detection of pancreatic tumours: comparison with helical CT

The aim was to compare spiral CT and MRI enhanced with mangafodipir trisodium (Mn-DPDP) in the detection and staging of pancreatic lesions. 20 patients with suspected pancreatic cancer were included in a phase III study. Triphasic spiral CT (4 ml s-1) and MRI (axial T1 weighted turbo spin echo with and without fat suppression, T1 weighted gradient echo and T2 weighted turbo spin echo at 1.5 T) were performed. All sequences were repeated following contrast medium using the same instrument settings as in the unenhanced sequences. Mn-DPDP was administered by slow injection of 5 mumol kg-1 body weight. Imaging results were correlated with surgery, laparoscopy, biopsy and/or follow-up. Eight pancreatic adenocarcinomas were present. Ten patients had chronic pancreatitis, and two showed a stenosing papillitis. CT detected eight malignant lesions and MRI detected seven. One pancreatic cancer was not detected with MRI. CT and MRI excluded malignancy in nine patients. MRI and CT returned three false positive results. Mn-DPDP improved delineation of the lesion, resulting in a higher level of diagnostic confidence. Differentiation between pseudotumorous lesions in chronic pancreatitis and pancreatic carcinoma was difficult due to similar slight contrast enhancement. Owing to better delineation of the lesion and the higher confidence in diagnosis, MRI with Mn-DPDP may have the potential to improve the detection rate and the staging accuracy of focal pancreatic lesions. These results need to be confirmed in a larger patient trial.     

神经纤维瘤病I型的MRI研究

目的：回顾神经纤维瘤病I型（NF1）患者MRI表现，分析MR扫描序列及其诊断价值，以建立合适的MR成像方案，为NF1影像诊断提供有价值的依据。方法：对30例临床确诊为NF1患者采用本组MR成像方案进行扫描，主要包括：轴面SE序列T2WI；平扫矢状面SE脉冲序列T1WI；增强轴面或矢状面SE脉冲序列T1WI；轴面或冠状面液体衰减反转恢复（FLAIR）序列，同时分析病变的发病部位、数目、形态、信号的变化和病变的强化情况等。结果：MRI可见下列3种表现：（1）多发性脑内错构瘤：30例中25例在SE脉冲序列T2WI和FlAIR脉冲序列见高信号病灶，病灶主要位于苍白球、小脑和脑干。另外，25例中20例可见海马回、海马旁回等区晕状高信号改变。（2）视通道或下丘脑胶质瘤：视神经、视交叉增粗、扭曲；视交叉或下丘脑肿块，SE脉冲序列T2WI和FlAIR序列表现为不规则分叶状混杂信号肿块，在增强SE脉冲序列T1WI有明显不规则强化。（3）脊柱多发性神经纤维瘤：SE脉冲序列T2WI和脂肪抑制短时反转恢复（STIR）序列显示高信号沿脊神经分布的多发性肿瘤。结论：MRI能够作为1种 常规的影像检查方法对NF1患者进行诊断和追踪。本组MR成像方案能较好地显示NF1的多发性或多灶性病变。     

Extracerebral neoplastic manifestations in neurofibromatosis 1: integrated diagnostic imaging

PURPOSE: To analyze the extracerebral manifestations of type 1 neurofibromatosis (NF-1), with special reference to peripheral nerve tumors. MATERIAL AND METHODS: The findings of 376 NF-1 patients (194 men and 182 women; age range: 0.1-48 years, mean: 8.1) were retrospectively reviewed. The patients had been submitted to abdominopelvic and superficial US and, in case of abnormal US findings or in the presence of symptoms, to CT and/or MRI. In addition, we considered 5 more patients (2 men and 3 women; age range: 50-72 years, mean: 64.4) with incomplete forms of NF-1 diagnosed after the finding of nerve sheath tumors. Biopsy (12 cases), surgery (10 cases), or clinical-instrumental follow-up were the study criteria. RESULTS: In the first group of patients we identified 91 cutaneous, 222 subcutaneous, 11 pendulous and 25 internal neurofibromas. Plexiform neurofibromas were found in the neck (1 case), chest (6 cases), abdomen (16), pelvis (8). We also found 1 benign and 1 malignant Schwannomas, 2 nerve sheath fibrosarcomas, 1 dopamine-producing sympatoma and 1 spermacytoma. As for the second group of patients, we had 2 Schwannomas, 1 pulmonary neurofibroma, and 2 multiple plexiform neurofibromas. The neurofibromas exhibited homogeneous US hypoechogenicity or slight echogenicity, with little contrast enhancement at CT. MR showed peripheral hyperintensity and central hypointensity on T2-weighted sequences and marked contrast enhancement after gadolinium, sometimes with mostly central uptake. The plexiform neurofibromas, which are typical of NF-1, had poorly-defined or infiltrating margins, with similar findings to the previous ones but sometimes with less homogeneous patterns at both US and CT. The Schwannomas, which are a less common finding in NF-1, exhibited different features at MRI and CT, namely pseudo-liquid or solid-inhomogeneous patterns with irregular and inhomogeneous contrast enhancement relative to the Antoni A/B tumor component. In the malignant lesions we observed infiltrating patterns, with irregular and inhomogeneous contrast enhancement, arranged asymmetrically relative to the contralateral lesion. CONCLUSIONS: Extra-axial neoplasms are a frequent finding in NF-1. Despite the extremely variable appearances of some lesions (particularly Schwannomas), the typical plexiform neurofibroma exhibits characteristic patterns. The diagnosis of malignancy often requires bioptic confirmation.     

[<Superscript>18</Superscript>F]FDG PET/CT in the diagnosis of malignant peripheral nerve sheath tumours in neurofibromatosis type-1

Purpose  The detection of malignant peripheral nerve sheath tumours (MPNSTs) in patients with neurofibromatosis 1 (NF1) remains a clinical challenge. The purpose of this study was to evaluate the use of [¹⁸F]2-fluoro-2-deoxy-d-glucose PET/CT (FDG PET/CT with early and delayed imaging) in patients with symptomatic neurofibromas, to revalidate current cut-off values for identification of malignant change within neurofibromas and to examine the relationship between SUV and tumour grade. Methods  Patients with symptomatic neurofibromas underwent FDG PET/CT imaging at 90 and 240 min. Semiquantitative analysis using maximum standardized uptake value (SUVmax) was performed and correlated with histology. Result  In 69 patients, 85 lesions were identified for analysis, including 10 atypical neurofibromas and 21 MPNSTs. Sensitivity of FDG PET/CT in diagnosing NF1-associated MPNST was 0.97 (95% CI 0.81–0.99) and the specificity was 0.87 (CI 0.74–0.95). There was a significant difference in SUVmax between early and delayed imaging and in SUVmax between tumours identified as benign and malignant on PET/CT. There was also a significant difference in SUVmax between tumour grades. Conclusion  FDG PET/CT is a highly sensitive and specific imaging modality for the diagnosis of MPNST in NF1 patients. We recommend performing early (90 min) and delayed imaging at 4 h for accurate lesion characterization and using a cut-off SUVmax of 3.5 on delayed imaging to achieve maximal sensitivity.     

Breast augmentation and reconstructive surgery: MR imaging of implant rupture and malignancy

The purpose of this study was to assess the diagnostic accuracy of MRI in detecting prosthesis integrity and malignancy after breast augmentation and reconstruction. Forty-one implants in 25 patients were analyzed by MRI before surgical removal. Imaging results were compared with ex vivo findings. Magnetic resonance imaging of the breast was performed on a 1.5-T system using a dedicated surface breast coil. Axial and sagittal T2-weighted fast spin-echo as well as dynamic contrast-enhanced T1-weighted gradient-recalled-echo sequences were acquired. The linguine sign indicating collapse of the silicone shell or siliconomas indicating free silicone proved implant rupture, whereas early focal contrast enhancement of a lesion was suspicious for malignancy. The sensitivity for detection of implant rupture was 86.7% with a specificity of 88.5%. The positive and negative predictive values were 81.3 and 92.0%, respectively. The linguine sign as a predictor of intracapsular implant rupture had a sensitivity of 80% with a specificity of 96.2%. Magnetic resonance imaging revealed two lesions with suspicious contrast enhancement (one carcinoma, one extra-abdominal fibromatosis). Magnetic resonance imaging is a reliable and reproducible technique for diagnosing both implant rupture and malignant lesions in women after breast augmentation and reconstruction.     

多发椎体压缩骨折良恶性MRI鉴别诊断

目的MRI鉴别多发椎体良恶性压缩骨折。方法171个椎体压缩骨折（良性77个、恶性94个）,16个经椎体活检,其余经3～6个月MRI追踪确诊。行T     

Focal hepatic lesions: differentiation with MR imaging at 0.5 T

Magnetic resonance (MR) examinations of 43 patients with 95 focal hepatic lesions (diameter, greater than 1 cm) were analyzed for lesion shape, homogeneity, and relative signal intensity compared with normal liver parenchyma, spleen, and skeletal muscle. On T1-weighted, balanced, and T2-weighted images, most metastases (74%), cavernous hemangiomas (76%), and cysts (82%) were smooth and round or oval, while the hepatocellular carcinomas all had irregular borders (40%) or were lobulated (60%). All lesions with irregular borders were malignant. Seventy percent of metastatic lesions, 85% of cavernous hemangiomas, and 100% of simple hepatic cysts were of homogeneous signal intensity, while 60% of hepatocellular carcinomas were inhomogeneous. Logistic regression analysis of multiple lesion characteristics showed that inhomogeneous lesions had a high likelihood of malignancy, while markedly hyperintense lesions had a very low probability of being malignant, regardless of other traits. Homogeneous lesions that were isointense or hyperintense compared with spleen on balanced images but were not markedly hyperintense on T2-weighted images also had a high likelihood of malignancy.     

毛细胞型星形细胞瘤的CT、MRI表现及病理学基础

目的:探讨脑内毛细胞型星形细胞瘤(PA)的CT、MRI表现及病理学基础,以提高对此病的认识.材料和方法:回顾性分析经手术病理证实的脑内典型PA 13例的CT与MRI表现.结果:位于小脑半球4例、小脑蚓部7例、右侧大脑半球2例.病变大小2.3cm×2.0cm×2.7cm～4.5cm×4.8cm×5.6cm.实性病变3例,CT平扫呈等密度软组织肿块,T1WI呈等信号,T2WI呈长信号或长信号中见少量短信号的混杂信号,CT及MRI增强后均表现为均质或不均质明显增强,其中2例病灶中心见少量无增强的低信号区,1例CT平扫见钙化灶.囊实性10例,MRI平扫显示肿瘤囊性部分呈长T1、长T2信号,实性部分呈等T1长T2信号,增强扫描实性部分明显增强,囊性部分无增强,3例见明显增强壁结节,2例病变呈多房性,增强后分隔明显增强,其中1例见短T1、长T2出血灶 .结论:脑内PA的CT与MRI表现具有一定的特征性,结合临床资料有助于术前诊断.     

鼻腔及鼻窦内翻性乳头状瘤的MRI诊断

目的 探讨鼻腔、鼻窦内翻性乳头状瘤的MRI表现,提高其诊断准确性.方法 回顾性分析36例经组织学证实的鼻腔、鼻窦内翻性乳头状瘤的MRl资料.结果 36例内翻乳头状瘤源于鼻腔外侧壁25例,上颌窦4例,筛窦2例,额、筛窦2例,筛、蝶窦2例,额窦1例;其中11例为复发病例,3例伴恶变.26例呈分叶状,10例形状不规则.病灶最大径22～82 mm,平均38 mm.36例边界均清楚.与邻近肌肉比较,MR T1WI呈等信号32例,稍高信号4例;T2WI呈不均匀高信号34例,不均匀等信号2例(伴恶变).与鼻中隔黏膜比较,增强后呈明显不均匀强化34例;32例病变在T2WI或增强T1聊上病变内部呈较规整的栅栏状,2例旱不规整的栅栏状(伴恶变).8例行MR动态增强扫描,其中7例时间-信号强度曲线(TIC)为速升缓降型,另1例局部区域的曲线呈速升速降型(伴恶变).结论 MR T2WI或增强T1WI上呈较规整的栅栏状外观是诊断鼻腔、鼻窦内翻性乳头状瘤的可靠征象,形态不规整可能提示伴发恶变.     

MRI in methotrexate-related leukoencephalopathy: Disseminated necrotising leukoencephalopathy in comparison with mild leukoencephalopathy

We report two fatal cases of methotrexate (MTX)-induced disseminated necrotising leukoencephalopathy (DNL) in which MRI was repeated from the onset. Initial T2-weighted images showed multiple areas of high signal, mainly in deep cerebral white matter, which on follow-up, spread and coalesced to involve the entire white matter. Small irregular low-signal foci on T2-weighted images were seen within the high-signal lesions. Multiple areas of contrast enhancement corresponded to these low-signal foci. The condition of both patients deteriorated and they died. We compared their MRI findings with those of seven patients with mild MTX-related leukoencephalopathy, six of whom were asymptomatic; one had transient neurological symptoms. They showed no contrast enhancement, but rather mild-to-moderate diffuse high signal in deep white matter, which later disappeared. These findings suggest that multiple low-signal foci on T2-weighted images with contrast enhancement may be characteristic of DNL, and that contrast-enhanced imaging is useful to differentiate this condition from mild leukoencephalopathy.     

<Superscript>18</Superscript>F-DOPA positron emission tomography for the detection of glomus tumours

The purpose of this study was to evaluate (18)F-DOPA whole-body positron emission tomography ((18)F-DOPA PET) as a biochemical imaging approach for the detection of glomus tumours. (18)F-DOPA PET and magnetic resonance imaging (MRI) were performed in ten consecutive patients with proven mutations of the succinate dehydrogenase subunit D ( SDHD) gene predisposing to the development of glomus tumours and other paragangliomas. (18)F-DOPA PET and MRI were performed according to standard protocols. Both methods were assessed under blinded conditions by two experienced specialists in nuclear medicine (PET) and diagnostic radiology (MRI). Afterwards the results were compared. A total of 15 lesions (four solitary and four multifocal tumours, the latter including 11 lesions) were detected by (18)F-DOPA PET. Under blinded conditions, (18)F-DOPA PET and MRI revealed full agreement in seven patients, partial agreement in two and complete disagreement in one. Eleven of the 15 presumed tumours diagnosed by (18)F-DOPA PET were confirmed by MRI. The correlation of (18)F-DOPA PET and MRI confirmed three further lesions previously only detected by PET. All of them were smaller than 1 cm and had the signal characteristics of lymph nodes. For one small lesion diagnosed by PET, no morphological MRI correlate could be found even retrospectively. No tumour was detected by MRI that was negative on (18)F-DOPA PET. All tumours diagnosed by MRI showed a hyperintense signal on T2-weighted images and a distinct enhancement of contrast medium on T1-weighted images. The mean tumour size was 1.5+/-0.5 cm. (18)F-DOPA PET seems to be a highly sensitive metabolic imaging procedure for the detection of glomus tumours and may have potential as a screening method for glomus tumours in patients with SDHD gene mutations.     

MR imaging-detected breast lesions: histopathologic correlation of lesion characteristics and signal intensity data

OBJECTIVE: The aim of our study was to differentiate benign from malignant breast lesions that had been detected exclusively on MR imaging by analyzing qualitative and quantitative lesion characteristics. MATERIALS AND METHODS: We performed 51 MR imaging-guided breast interventions (41 preoperative lesion localizations and 10 large-core needle biopsies) in 45 patients with exclusively MR imaging-detected lesions. All patients had previously undergone diagnostic dynamic contrast-enhanced MR imaging of the breast with a double breast coil at 1.0 T (n = 36) or 1.5 T (n = 15). The diagnostic MR images were evaluated on a workstation. Lesion morphology (size, shape, margin type, enhancement pattern), signal intensity parameters (time to peak enhancement, maximum slope of enhancement curve, washout, relative water content), and scores analogous to the Breast Imaging Reporting and Data System (BI-RADS) categories were correlated with histology. RESULTS: Histology revealed malignancy in 37.3% (19/51) of the lesions. The positive predictive value for malignancy of exclusively MR imaging-detectable lesions increased as the analogous BI-RADS category increased. Late inhomogeneous contrast enhancement was the only morphologic criterion that was statistically significantly correlated with malignancy. Malignant and benign lesions did not differ significantly in any of the quantitatively evaluated signal intensity parameters. Carcinomas showed a tendency toward faster and stronger enhancement and stronger washout. CONCLUSION: The classification of exclusively MR imaging-detectable breast lesions according to a combination of morphologic and perfusion parameters including the late enhancement pattern helps identify the lesions for which interventional MR imaging is required. Quantitative signal intensity data alone do not suffice.     

Diagnostic Accuracy of Multiparametric Magnetic Resonance Imaging for Differentiation Between Parotid Neoplasms

PurposeThis study was designed to evaluate the role of multiparametric magnetic resonance imaging (MRI) for differentiation of parotid gland neoplasms.MethodsProspective study was conducted upon 52 consecutive patients (30 men, 22 women; aged 24–78 years; mean, 51 years) with parotid tumours that underwent multiparametric MRI using combined static MRI, dynamic contrast enhanced (DCE) MRI, and diffusion-weighted imaging (DWI). The static MRI parameter, time signal intensity curves (TIC) derived from DCE-MRI, and apparent diffusion coefficient (ADC) values of parotid tumours were correlated with histopathological findings.ResultsStatic MRI revealed a significant difference between both benign and malignant lesions in regards to margin definition (P < .001) and T2 hypointensity (P < .013), with a diagnostic accuracy 95% and 78.33% respectively. Study of the TIC type on DCE-MRI revealed statistically significant difference between benign and malignant lesions (P < .001) and diagnostic accuracy 96.55%. There was no statistically significant difference (P = .181) between the ADC values of benign and malignant lesions. ROC curve analysis revealed that by using ADC cut-off value of 1 × 10^?3 mm²/s had accuracy of 84.62% respectively for differentiating Warthin from malignant tumours that could be modified to higher value (94.28%) by excluding lymphoma from malignant lesions. By using cutoff value of 1.3 × 10^?3 mm²/s to differentiate pleomorphic adenoma from malignancy, ROC curve analysis had high accuracy of 97.06%.ConclusionMultiparametric MRI can be used for differentiation of malignant from benign parotid tumours and characterization of some benign parotid tumours.