Differentiating intracranial solitary fibrous tumor/hemangiopericytoma from meningioma using diffusion-weighted imaging and susceptibility-weighted imaging

Neuroradiology - Intracranial solitary fibrous tumor/hemangiopericytoma (SFT/HPC) and meningioma are difficult to distinguish owing to their overlapping imaging manifestation on routine magnetic...     

微囊型脑膜瘤的磁共振成像诊断

目的探讨微囊型脑膜瘤的磁共振成像（MRI）影像表现,以提高对本病的认识和诊断正确率。方法回顾性分析13例经病理证实的微囊型脑膜瘤的MRI平扫及增强扫描影像资料。结果 13例中病变位于额叶5例,颞叶2例,顶叶4例,右侧桥脑小脑角区1例,鞍区1例;9例平扫T₁WI呈低信号,T₂WI呈明显高信号,增强后病变呈明显不均匀强化;4例平扫时T₁WI呈不均匀等低信号,T₂WI呈不均匀等高混杂信号,增强后病变呈明显不均匀强化;6例可见脑膜尾征;8例可见中、重度瘤周水肿。结论微囊型脑膜瘤是颅内少见肿瘤,其MRI表现有一定特点,对其诊断和鉴别诊断具有重要临床价值。     

Intraosseous microcystic meningioma

Extradural ectopic meningioma is a rare tumor. We report on an example of microcystic meningioma arising in the skull of an elderly woman. Radiological examination revealed a localized osteolytic lesion in the left parietal bone. At surgery, it was discovered that the tumor was located within the skull without any evidence of extraosseous extension. The light microscopic, immunohistochemical and ultrastructural features were consistent with a microcystic variant of meningioma. To our knowledge, this is the first case of an intraosseous microcystic meningioma, and we believe that this type of meningioma should be considered in the differential diagnoses of myxoid bone tumors of the calvarium. Received: 10 January 2000 Revision requested: 21 February 2000 Revision received: 8 March 2000 Accepted: 13 March 2000     

Differentiating primary hepatic angiosarcomas from hemangiomatosis and epithelioid hemangioendotheliomas using gadoxetic acid-enhanced and diffusion-weighted MR imaging

Objectives

To assess the value of gadoxetic acid-enhanced and diffusion-weighted (DW) magnetic resonance (MR) imaging for differentiating primary hepatic angiosarcomas from hemangiomatosis and epithelioid hemangioendotheliomas (EHEs).

Methods

We reviewed MR images of seven patients with pathologically determined hepatic angiosarcomas, 11 patients with hemangiomatosis, and five patients with EHEs. Two radiologists assessed morphologic features, signal intensity (SI), enhancement patterns, and the presence of diffusion restriction by consensus and compared between angiosarcoma vs hemangiomatosis and angiosarcoma vs EHEs.

Results

Angiosarcomas more frequently showed mixed well- and ill-defined margins (6, 85.7%), mixed strong and intermediate-high SI (5, 71.4%) on T2-weighted images, mixed peripheral and/or central nodular and rim and/or target enhancement (5, 71.4%), and mixed presence and absence of diffusion restriction (7, 100%) compared with hemangiomatosis and EHEs (P < 0.05). The overall survival rate in patients with angiosarcomas was 42.9% at 3 months and 14.3% at 14 months, whereas all patients with EHEs were alive during the follow-up period from 4 to 43 months (P = 0.002).

Conclusion

Gadoxetic acid-enhanced and DW MR imaging may help differentiate primary hepatic angiosarcomas with hemangioma-like appearance, EHE-like appearance, or both; and poor prognosis from hemangiomatosis and EHEs.

     

The contribution of diffusion-weighted MR imaging to distinguishing typical from atypical meningiomas

Introduction Atypical/malignant meningiomas recur more frequently then typical meningiomas. In this study, the contribution of diffusion-weighted MR imaging to the differentiation of atypical/malignant and typical meningiomas and to the determination of histological subtypes of typical meningiomas was investigated.Methods The study was performed prospectively on 39 patients. The signal intensity of the lesions was evaluated on trace and apparent diffusion coefficient (ADC) images. ADC values were measured in the lesions and peritumoral edema. Student’s t-test was used for statistical analysis. P<0.05 was considered statistically significant.Results Mean ADC values in atypical/malignant and typical meningiomas were 0.75±0.21 and 1.17±0.21, respectively. Mean ADC values for subtypes of typical meningiomas were as follows: meningothelial, 1.09±0.20; transitional, 1.19±0.07; fibroblastic, 1.29±0.28; and angiomatous, 1.48±0.10. Normal white matter was 0.91±0.10. ADC values of typical meningiomas and atypical/malignant meningiomas significantly differed (P<0.001). However, the difference between peritumoral edema ADC values was not significant (P>0.05). Furthermore, the difference between the subtypes of typical meningiomas and atypical/malignant meningiomas was significant (P<0.001). Conclusion Diffusion-weighted MR imaging findings of atypical/malignant meningiomas and typical meningiomas differ. Atypical/malignant meningiomas have lower intratumoral ADC values than typical meningiomas. Mean ADC values for peritumoral edema do not differ between typical and atypical meningiomas.     

Magnetic resonance imaging and diffusion-weighted images of cystic meningioma: correlating with histopathology

BACKGROUND AND PURPOSE: Cystic meningiomas are quite rare, accounting for between 2% and 4% of all intracranial meningiomas. To better understand all the types of cystic meningiomas with magnetic resonance imaging (MRI), diffusion-weighted imaging (DWI) and histopathology, we attempted to correlate the MRI and DWI features of cystic meningiomas with the histopathological findings. METHODS: We collected 15 cases of cystic meningiomas diagnosed between 1993 and 2000 (5 men and 10 women, 41-80 years old). Fifteen patients had conventional MRI and 14 patients had CT scan. DWI was also performed in three patients. Apparent diffusion coefficient (ADC) images were also done. In the classification of cystic meningiomas, we adopted Worthington's classification, which divides cystic meningiomas into five groups. RESULTS: Tumor resection was performed in all patients. Tumor locations were as follows: convexity (10), falx (2), pterion (2) and lateral ventricle (1). Regarding the types of cystic lesion, type I (3), type II (3), type III (3), type IV (1) and type V (5) were found. Histopathologically, there were six atypical, four meningothelial, two malignant, one fibroblastic, one angiomatous and one transitional. Intratumoral cystic meningiomas were more common in atypical types. Peritumoral cystic meningiomas were more common in meningothelial and atypical types. The cystic portion of the three cystic meningiomas was hypointense or mildly hyperintense on DWI. ADC ratio (ADCR) of DWI for cyst part of two type I cystic meningiomas was 1.25 and 0.82; for cyst part of one type III was 4.04. CONCLUSIONS: It is important to recognize the neuroimaging features of the cystic meningiomas. Conventional MRI and DWI may play an important role in the preoperative radiological evaluation and the recognition of these types of cysts for proper surgical treatment.     

Differentiating primary CNS lymphoma from glioblastoma multiforme: assessment using arterial spin labeling, diffusion-weighted imaging, and 18F-fluorodeoxyglucose positron emission tomography

Introduction

Our purpose was to evaluate the diagnostic performance of arterial spin labeling (ASL) perfusion imaging, diffusion-weighted imaging (DWI), and ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG-PET) in differentiating primary central nervous system lymphomas (PCNSLs) from glioblastoma multiformes (GBMs).

Methods

Fifty-six patients including 19 with PCNSL and 37 with GBM were retrospectively studied. From the ASL data, an absolute tumor blood flow (aTBF) and a relative tumor blood flow (rTBF) were obtained within the enhancing portion of each tumor. In addition, the minimum apparent diffusion coefficient (ADCmin) and the maximum standard uptake value (SUVmax) were obtained from DWI and FDG-PET data, respectively. Each of the four parameters was compared between PCNSLs and GBMs using Kruskal–Wallis test. The performance in discriminating between PCNSLs and GBMs was evaluated using the receiver-operating characteristics analysis. Area-under-the-curve (AUC) values were compared among the four parameters using a nonparametric method.

Results

The aTBF, rTBF, and ADCmin were significantly higher in GBMs (mean aTBF ± SD?=?91.6?±?56.0 mL/100 g/min, mean rTBF ± SD?=?2.61?±?1.61, mean ADCmin ± SD?=?0.78?±?0.19?×?10^?3 mm²/s) than in PCNSLs (mean aTBF ± SD?=?37.3?±?10.5 mL/100 g/min, mean rTBF ± SD?=?1.24?±?0.37, mean ADCmin ± SD?=?0.61?±?0.13?×?10^?3 mm²/s) (p?<?0.005, respectively). In addition, SUVmax was significantly lower in GBMs (mean ± SD?=?13.1?±?6.34) than in PCNSLs (mean ± SD?=?22.5?±?7.83) (p?<?0.005). The AUC for aTBF (0.888) was higher than those for rTBF (0.810), ADCmin (0.768), and SUVmax (0.848), although their difference was not statistically significant.

Conclusion

ASL perfusion imaging is useful for differentiating PCNSLs from GBMs as well as DWI and FDG-PET.     

非典型脑膜瘤的MRI诊断

目的:分析非典型脑膜瘤的MRI表现及病理基础,以提高对该肿瘤的认识.方法:回顾性分析经手术病理证实的15例非典型脑膜瘤的MRI表现,探讨肿瘤的部位、形态、有无出血囊变、瘤体占位效应、瘤周水肿、瘤体信号及强化特点,并行病理对照分析.结果:本组15例非典型脑膜瘤,部位典型者13例(86.7%),典型部位以大脑镰、矢状窦旁、...     

非典型性脑膜瘤的MRI表现

目的：分析非典型性脑膜瘤MRI征象及其预后。方法：回顾性分析经手病理证实为非典型性脑膜瘤共20例;探究其预后情况。结果：20例非典型性脑膜瘤中17例部位均较典型,不典型部位在侧脑室三角区、视神经各1例,多发者1例。病灶呈类圆形或半圆形,略呈分叶状状,信号多表现不均匀,其中出血者2例,明显囊变者3例,瘤周不同程度水肿,有脑膜尾征15例,表现为均匀线状或粗细不一。4例骨质改变,术后残留或复发6例。20例术前MRI诊断为脑膜瘤者18例,误诊2例,误诊率为10%。结论：非典型性脑膜瘤的MRI表现有一定特征性,具有一定的侵袭性;充分认识非典型性脑膜瘤的MRI特点及肿瘤与邻近结构的关系,对肿瘤的定性以及制定手术方案有重要的指导作用。     

Differentiating malignant from benign hyperintense nodules on unenhanced T1-weighted images in patients with chronic liver disease: using gadoxetic acid-enhanced and diffusion-weighted MR imaging

Purpose

To evaluate value of gadoxetic acid-enhanced and diffusion-weighted (DW) MRI for distinguishing malignant from benign hyperintense nodules on unenhanced T1-weighted images (T1WIs) in patients with chronic liver disease.

Materials and methods

Forty-two patients with 37 malignant and 41 benign hyperintense nodules on unenhanced T1WIs who underwent gadoxetic acid-enhanced and DW MRI, followed by histopathological examination, were included. Qualitative and quantitative analyses were conducted. Significant findings on univariate and multivariate analyses were identified and their diagnostic performances were analyzed for predicting hyperintense hepatocellular carcinomas (HCCs).

Results

In univariate analysis, hyperintensity on T2WI, arterial enhancement, washout, hypointensity on hepatobiliary phase, and diffusion restriction were more frequently observed (P?<?0.05) in hyperintense HCCs. Tumor-to-liver SI ratio on hepatobiliary phase and minimum apparent diffusion coefficient (ADC_min) were significantly lower in hyperintense HCCs (P?<?0.05). In multivariate analysis, hyperintensity on T2WI (OR, 13.58; P?=?0.02), arterial enhancement (OR, 8.21; P?=?0.002), and ADC_min?≤?0.83?×?10^?3 mm²/s (OR, 6.88; P?=?0.008) were independently significant factors for predicting hyperintense HCCs. When two of three criteria were combined, 75.7% (28/37) of hyperintense HCCs were identified with a specificity of 92.7%, and when all three criteria were satisfied, the specificity was 97.6%.

Conclusion

Gadoxetic acid-enhanced and DW MRI may be helpful for differentiating malignant from benign hyperintense nodules on unenhanced T1WI.

     

能谱CT成像在鉴别周围型肺癌和肺炎性肿块中的价值

目的 探讨能谱CT成像定量分析在鉴别诊断周围型肺癌和肺炎性肿块中的价值.方法 对60例肺内孤立性肿块(周围型肺癌35例、肺炎性肿块25例)行宝石CT能谱模式(GSI)扫描,获得动脉期和静脉期的能谱系列图像.分别测量病灶中央区、周围区的碘浓度,计算其与同层面胸主动脉碘浓度的比值即标准化碘浓度(NIC),同时计算病灶中央区与周围区标准化碘浓度之差的绝对值(dNIC).自动获取能谱衰减曲线并计算其斜率(λHU).测量数据以M(Q1,Q3)表示,分别对上述参数进行2组独立样本Wilcoxon符号秩和检验,并绘制ROC曲线评估其诊断效能.结果 能谱模式双期扫描周围型肺癌中央区NIC值均明显低于炎性肿块:动脉期分别为0.03(0,0.05)和0.12(0.07,0.20),静脉期分别为0.14(0.12,0.19)和0.30 (0.21,0.57),差异均有统计学意义(Z值分别为-4.14、-3.70,P值均＜0.01).而周围型肺癌dNIC值明显高于炎性肿块:动脉期分别为0.08 (0.05,0.11)和0.04(-0.02,0.08),静脉期分别为0.23(0.17,0.34)和0.07(-0.04,0.08),差异均有统计学意义(Z值分别为-2.56、-4.00,P值均＜0.05).双期扫描中周围型肺癌λHU值均低于肺炎性肿块:动脉期分别为1.03(0.67,1.67)和2.75(1.61,3.19),静脉期分别为1.58 (1.30,2.17)和3.25(2.37,4.54),差异均有统计学意义(Z值分别为-3.90、-4.42,P值均＜0.01).ROC曲线显示以静脉期λHU=2.11为阈值时,对2组病变鉴别诊断的敏感度可达89％,特异度可达91％.结论 运用能谱CT成像的参数进行定量分析,对周围型肺癌和肺炎性肿块的鉴别诊断有较大价值.     

APT在胶质瘤假性进展与复发鉴别中的应用

目前,高级别胶质瘤术后常辅以放疗或同步放化疗。治疗后呈现的假性进展与肿瘤复发在常规MRI中表现极为相似,两者在临床上难于鉴别。酰胺质子转移（APT）技术通过检查组织中的酰胺质子含量对鉴别两者有较高的敏感性和特异性。就APT在胶质瘤假性进展与复发鉴别中的应用,以及相比动态磁敏感对比增强灌注加权成像（DSC-PWI）、磁共振波谱成像（MRS）、PET技术的优势予以综述。     

Assessment of patency capsule retention using MR diffusion-weighted imaging

Objectives

Evaluate the ability of MR diffusion-weighted imaging (DWI) to predict patency capsule retention in Crohn’s disease (CD).

Methods

Clinical and imaging data were prospectively reviewed for 80 CD patients following patency capsule administration and MR-DWI under institutional review board (IRB) approval with informed consent. Two radiologists separately assessed the presence/absence of restricted diffusion in the distal ileum. Apparent diffusion coefficients (ADC) from three regions of interest on the ileal wall were averaged. The association between restricted diffusion and retention, and sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated. Ability of ADC to predict retention was assessed with receiver operating characteristic (ROC) curve analysis.

Results

Restricted diffusion in the distal ileum was associated with capsule retention (p?=?0.001, p?<?0.0001). Sensitivity, specificity, PPV and NPV of restricted diffusion for capsule retention were 100.0%, 46.2%, 30.0%, 100% and 100.0%, 56.9%, 34.9%, 100%, respectively, for two radiologists. Accuracy of ADC to predict retention was high (area under the curve?=?0.851, p?<?0.0001). An ADC of 1.47 mm²/s showed 90.0% sensitivity and 50.0% specificity for retention.

Conclusions

Sensitivity and NPV of restricted diffusion for patency capsule retention were 100%, suggesting that DWI may predict gastrointestinal tract capability to pass video camera endoscopy.

Key Points

? Capsule endoscopy enables assessment of the gastrointestinal mucosa in Crohn’s disease ? Prior patency capsule administration is recommended to evaluate gastrointestinal tract patency ? MR diffusion-weighted imaging may detect pathological constriction of the ileum ? Restricted diffusion in the distal ileum was associated with capsule retention ? MR-DWI may predict gastrointestinal tract capability to pass capsule endoscopy