Dural tail sign in spinal meningiomas

OBJECTIVE: To study the association between the "dural tail sign" and spinal meningiomas on MR imaging. METHODS: Retrospective review of MR examinations of all pathologically proven spinal meningiomas from 1998 to 2005 was performed. Lesions were evaluated for size, signal intensity, enhancement pattern, and presence or absence of dural tail. The dural tail length and direction in reference to the meningioma were also evaluated. RESULTS: Seven spinal meningiomas were identified in seven patients. One lesion was purely extradural, while the remaining were intradural extramedullary. Dural tail was present in four cases (57%) and its length ranged between 5 and 21 mm. The tail was seen cranial and caudal to the meningioma in three cases and only cranially in one. Coronal images were available in three cases and in two of these; the dural tail was clearly depicted. CONCLUSIONS: "Dural tail sign" is as common in spinal meningiomas as in cranial meningiomas.     

脑膜尾征”：与脑膜瘤相关的MR强化表现

目的分析脑膜瘤脑膜尾征的MR表现及组织学特点。方法对32例脑膜瘤患者均行MR平扫及增强扫描。结果32例34个脑膜瘤病灶中有23个病灶（67.6%）显示脑膜尾征,且与肿瘤的大小与位置无关。结论脑膜尾征是脑膜瘤在MR增强扫描时较常见和特有的表现,而且脑膜尾征与肿瘤侵犯脑膜部分相关。     

A review on dural tail sign

"Dural tail sign" (DTS) which is a thickening of the dura adjacent to an intracranial pathology on contrast-enhanced T1 MR Images, was first thought to be pathognomonic of meningioma, however, many subsequent studies demonstrated this sign adjacent to various intra- and extra-cranial pathologies and in spinal lesions. In this paper we outline the history, accompanying pathologies and the differentiation and probable pathophysiology of DTS. We also discuss whether we can predict tumoral involvement of the dural tail before surgery and whether the dural tail adjacent to a tumor should be resected.     

Application of arterial spin labeling perfusion MRI to differentiate benign from malignant intracranial meningiomas

PurposeDifferentiating WHO grade I–III of meningioma by non-invasive imaging is challenging. This study investigated the potential of MR arterial spin labeling (ASL) to establish tumor grade in meningioma patients.Material and methodsPseudo-continuous ASL with 3D background suppressed gradient and spin echo (GRASE) was acquired on 54 patients with newly diagnosed or recurrent intracranial meningioma. Perfusion patterns characterized in CBF color maps were independently evaluated by three neuroradiologists blinded to patient history, and correlated with tumor grade from histo-pathological review.ResultsThree perfusion patterns could be discerned by visual evaluation of CBF maps. Pattern 1 consisted of homogeneous hyper-perfusion of the entire tumor; pattern 2 demonstrated heterogeneous hyper-perfusion; pattern 3 showed no substantial hyper-perfusion. Evaluation of the perfusion patterns was highly concordant among the three readers (Kendall W = 0.9458, P < 0.0001). Pattern 1 was associated with WHO Grade I meningioma of (P < 0.0001). Patterns 2 and 3 were predictive of WHO Grade II and III meningioma (P < 0.0001), with an odds ratio (OR, versus pattern 1) of 49.6 (P < 0.01) in a univariate analysis, and an OR of 186.4 (P < 0.01) in a multivariate analysis.ConclusionQualitative evaluation of ASL CBF maps can help differentiate benign (WHO Grade I) from higher grade (WHO Grade II and III) intracranial meningiomas, potentially impacting therapeutic strategy.     

An observational study of skier compliance with posted “slow” signs and ski patrollers

ObjectivesTo examine the efficacy of “slow” signs and patroller presence at “slow” signs to reduce speeds of snowsports participants, compared to a condition where no sign or patroller are present, independent of other factors that may contribute to skier slowing (such as prior knowledge, trail convergence, etc.).Design and methodsSnowsports participant speeds were measured on “more difficult” trails using a radar gun at two ski areas with: (1) no-sign — the usual condition for the trail, and (2) slow-sign — a large “slow” sign was posted in the middle of the trail. At one ski area, a third condition was also tested: (3) slow + patroller — a ski patroller stood at the slow sign. Participant equipment type and estimated ability were also recorded.ResultsAt one ski area, there was no significant difference in speed between conditions. At the second ski area, the differences in mean (SD) speeds were small but significant for the no-sign, slow-sign, and slow + patroller conditions: 10.9 (3.0), 10.3 (2.9), and 9.8 (2.6) m/s. Effects were driven by non-beginner skiers; on average, beginner skiers and all snowboarders were slower than non-beginner skiers and did not adjust their speed in response to the signage conditions.ConclusionsReductions in speed for the slow-sign and slow + patroller conditions compared to the no-sign condition were small (0.5 and 1.1 m/s) compared to the variation in chosen skier speed reported in other studies. The small differences in chosen speeds make it unlikely that slow sign and patroller presence alone would produce meaningful reductions in collision likelihood or severity of impacts.     

Magnetic resonance imaging spectrum of spinal meningioma

PurposeTo evaluate magnetic resonance (MR) imaging findings of spinal meningioma and to determine the radiological subtypes based on the MR imaging findings and their respective clinical features.Material and methodsData for 105 patients with surgically treated and histopathologically diagnosed spinal meningiomas at our hospital between May 1, 2003 and May 1, 2017 were evaluated in this study. Two radiologists reviewed the characteristics of spinal meningiomas on MR images and categorized the spinal meningiomas into subtypes based on MR imaging findings.ResultsMost spinal meningiomas showed higher signal intensity than that of the spinal cord but lower than that of the subcutaneous fat on T2-weighted images (WI). 56 cases (54%) showed adjacent spinal cord signal changes. Meningiomas could be categorized according to MR imaging findings into type A: dural-based tumors with a homogeneous signal intensity and intense contrast enhancement (81 cases, 77%); type B: round or oval-shaped tumors with an internal hypointense portion on T2-weighted images (18 cases, 17%); type C: en plaque tumors (three cases, 3%); and type D: tumors with unusual findings and a heterogeneous appearance (three cases, 3%). All type C patients showed spinal cord signal changes.ConclusionsSpinal meningioma showed slightly high signal intensity rather than high signal intensity on T2-weighted images. Spinal cord signal changes were present in more than half of the cases. Clinical differences were observed among the different MR imaging types.     

Intracranial hemangiopericytomas: MR and CT features.

PURPOSETo describe the MR and CT imaging features of hemangiopericytoma and to identify the characteristics that might distinguish them from meningioma.METHODSWe retrospectively reviewed the CT and MR findings in 34 pathologically proved cases of hemangiopericytoma. We evaluated the size, shape, and location of the tumor; the presence of hydrocephalus, edema, and mass effect; the type of dural attachment (broad-based or narrow-based) and bone changes (erosion, hyperostosis); and the tumor''s density, signal, and contrast-enhancement characteristics.RESULTSThirty of 34 tumors were 4 cm or more in greatest dimension, 32 were lobular, and only seven were in the posterior fossa. Hydrocephalus was present in 18, edema in 30, and mass effect in 33. Twenty-three had broad-based dural attachment and 11 had narrow-based attachment. All 26 unenhanced CT scans showed hyperdense tumors; 19 were heterogeneous and seven homogeneous. All 27 contrast-enhanced CT scans showed enhancement; 17 were heterogeneous and 10 homogeneous. Bone erosion was present in 17 of 29 hemangiopericytomas imaged with CT. None had hyperostosis or tumor calcifications. On T1-weighted MR images, 13 of 17 tumors were isointense with cortical gray matter; on T2-weighted image, 10 of 17 were isointense. All 14 tumors imaged with contrast enhanced T1-weighted MR imaging showed enhancement, and 13 of these were heterogeneous; eight of the 14 had a "dural tail" sign.CONCLUSIONIntracranial hemangiopericytomas are multilobulated, extraaxial tumors, sometimes associated with narrow-based dural attachment and bone erosion. Unlike with meningiomas, hyperostosis and intratumoral calcification are not present.     

Implications of CT imaging for postplan quality assessment in prostate brachytherapy

PurposePostplan quality assurance using CT shows considerable interobserver contour variability. We examined CT postplans of four experienced brachytherapists for comparison with MR-determined prostate volumes.Methods and MaterialsSeventy-five patients had CT and MR scans 1 month post-¹²⁵I prostate brachytherapy. CT scans were contoured by the treating physician and dosimetry calculated. The prostate was contoured independently on MR by one observer with extensive MR experience, the scans were fused and dosimetric parameters compared.ResultsThe mean prostate volume on CT was 38.3 cc (17.5–78.6 cc), on MR 33.3 cc (16.3–66.1 cc). On average, the volume on CT was 16.1% larger than on MR (range, 8% smaller to 64% larger). Craniocaudal discordance of the CT vs. MR prostate contours ranged from 4 mm cranial to 10 mm caudal to MR base and from 6 mm cranial to 14 mm caudal to MR apex. The CT prostate volume not only included an average of 90% of the MR prostate (range, 75–99%) but also included normal tissue (mean, 8.3 cc; range, 2.9–17.1 cc). The average difference between the calculated D₉₀ from CT contours vs. MR contours was 10.0 Gy (standard deviation, 8.8; range, ?37.6 to +41.6 Gy).ConclusionsOn average, only 90% of the MR-defined prostate is included in CT contours, while a volume of normal tissue is erroneously designated as prostate. Lack of awareness of this deficiency in planning and/or operative technique gives a false sense of appreciation of the true conformality, delays implementation of corrective measures, and risks unnecessary side effects.     

椎管内脊膜瘤及神经源性肿瘤MRI增强影像的特征性分析

目的:分析椎管内脊膜瘤及神经源性肿瘤MR增强影像的特征。方法:搜集经手术病理证实的椎管内脊膜瘤11 例,神经源性肿瘤12例,全部病例均行MR平扫及增强扫描。结果:椎管内脊膜瘤MR增强影像特征为“肿瘤周边重度环状增强”、脊膜“尾巴征”;神经鞘瘤MR增强影像特征为多灶样不增强;神经纤维瘤MR增强影像特征为病灶内星芒状不增强。结论:椎管内脊膜瘤及神经源性肿瘤都有各自的MR增强影像特征,其对定性诊断有重要价值     

Dural "tail" associated with meningiomas on Gd-DTPA-enhanced MR images: characteristics, differential diagnostic value, and possible implications for treatment

Gadolinium-enhanced magnetic resonance (MR) imaging studies of 30 histologically proved cranial meningiomas revealed a linear enhanced structure or "tail" extending away from the tumor mass along the dural surface in 18 cases (60%). Contrast material-enhanced computed tomographic studies available in 10 of these 18 cases did not depict this structure. Characteristic features of this MR finding were reviewed, and criteria were defined to distinguish this tail from other enhanced structures. To assess the differential diagnostic value of this finding, gadolinium diethylenetriaminepentaacetic acid-enhanced MR studies of a control group of other extraaxial lesions as well as superficial intraaxial tumors that abut the meninges were reviewed. These cases failed to show this MR feature. Pathologic correlation was available in three meningiomas with the finding of a tail, and these demonstrated meningothelial tumor nodules in the samples taken from areas corresponding to the enhanced regions on MR images. This is in agreement with other recent pathologic studies of the dura mater surrounding meningiomas. The authors believe that the linear enhanced structure described may represent tissue containing tumoral nodules. Awareness of this MR sign may be useful in distinguishing meningiomas from other lesions and in planning total resection of the infiltrated dura mater.     

鞍结节脑膜瘤与向前上生长的垂体腺瘤MRI鉴别诊断

目的 探讨鞍结节脑膜瘤与向前上生长的垂体大腺瘤的影像学鉴别要点。资料与方法 分析17例经手术证实的鞍结节脑膜瘤的MRI征象,并与同期病理确诊的14例垂体大腺瘤进行对照。结果 17例脑膜瘤：均显著强化,包绕颈内动脉13例,长脑膜尾征14例、瘤周较多流空信号5例,蝶鞍扩大9例,垂体柄不能辨认11例,肿块与垂体分界不清7例,无腰征。14例垂体大腺瘤：7例显著强化、但不均匀,颈内动脉包绕14例,短脑膜尾征9例,较多流空信号2例,蝶鞍扩大14例,垂体柄不能辨认14例,见不到垂体结构13例,腰征12例。鞍结节脑膜瘤的瘤体显著及均匀强化、脑膜尾征粗大、瘤内星状改变均明显不同于垂体大腺瘤,其中长脑膜尾征、明显及均匀强化价值最大。结论 长脑膜尾征和肿瘤明显及均匀强化、无腰征是鞍结节脑膜瘤的特征性表现,对于鉴别鞍结节脑膜瘤与向前上生长的垂体大腺瘤具有重要价值。     

“Dural tail” adjacent to a giant posterior cerebral artery aneurysm: case report and review of the literature

The “dural tail” sign on gadolinium (Gd-DTPA)-enhanced MRI has been described in association with meningiomas. Various series with histopathological correlation have shown that in some cases there is tumour invasion into the dura mater, but in the majority of cases it represents a hypervascular, non-neoplastic reaction. While this sign was originally thought to be specific for meningioma, subsequent case reports have described the presence of a dural tail in other intra- and extra-axial lesions. We present a patient with a giant aneurysm arising from the P2 segment of the right posterior cerebral artery, adjacent to the tentorium, with a prominent dural tail on Gd-DTPA-enhanced MRI. In this location, differentiation of an aneurysm from a meningioma was critical. Received: 24 September 1996 Accepted: 7 October 1996     

Contribution of dynamic contrast MR imaging to the differentiation between dural metastasis and meningioma

Purpose To determine the perfusion-sensitive characteristics of cerebral dural metastases and compare them with the data on meningiomas.Methods Twenty-two patients presenting with dural tumor underwent conventional and dynamic susceptibility-contrast MR imaging: breast carcinoma metastases, two patients; colorectal carcinoma metastasis, one patient; lung carcinoma metastasis, one patient; Merkel carcinoma metastasis, one patient; lymphoma, one patient; meningiomas, 16 patients. The imaging characteristics were analyzed using conventional MR imaging. The cerebral blood volume (CBV) maps were obtained for each patient and the relative CBV (rCBV) in different areas was calculated using the ratio between the CBV in the pathological area (CBVp) and in the contralateral white matter (CBVn).Results The differentiation between a meningioma and a dural metastasis can be difficult using conventional MR imaging. The rCBVs of lung carcinoma metastasis (1 case: 1.26), lymphoma (1 case: 1.29), breast carcinoma metastasis (2 cases: 1.50,1.56) and rectal carcinoma metastasis (1 case: 3.34) were significantly lower than that of meningiomas (16 cases: mean rCBV = 8.97±4.34, range 4–18). Merkel carcinoma metastasis (1 case: 7.56) showed an elevated rCBV, not different from that of meningiomas.Conclusion Dural metastases are sometimes indistinguishable from meningiomas using conventional MR imaging. rCBV mapping can provide additional information by demonstrating a low rCBV which may suggest the diagnosis of metastasis.     

Magnetic resonance-guided focused ultrasound surgery using an enhanced sonication technique in a pig muscle model

The purpose of this studyTo evaluate the safety and efficacy of an enhanced magnetic resonance-guided focused ultrasound (MRgFUS) emission protocol that results in more extensive treatment by increasing the volume of each focal ablation using the same energy.Materials and methodsSix pigs were treated with an MRgFUS system combined with real-time MR, for imaging and temperature mapping, with 102 “enhanced” and 97 “regular” focal ablations performed on both buttock muscles. Real-time imaging, temperature mapping, and acoustic reflected spectrum data enabled immediate evaluation of the results. MR contrast-enhanced images and pathology examinations were used for confirmation.ResultsThe location of the ablated volume by “enhanced” sonication is predictable, with a maximum possible shift of 6 mm toward, and 3 mm away, from the transducer. The ablated volume after enhanced sonication was, on average, 1.8 times larger than after a regular sonication of the same energy. Pathology results showed the same thermally induced damage patterns in the enhanced sonications and the regular sonications.ConclusionAccelerated MRgFUS with enhanced sonication is a safe, controllable, and more effective tissue ablative modality than standard sonication. This new technology may significantly reduce the length of tumor ablation procedures. (Isn’t the new technology you’re talking about MRgFUS? If so, you don’t need to repeat it at the end of this sentence.)     

Clustering of screen time behaviours in adolescents and its association with waist circumference and cardiorespiratory fitness

ObjectivesTo identify the association of clusters of screen time (ST) behaviours with waist circumference (WC) and cardiorespiratory fitness (CRF) among adolescents.DesignCross-sectional study of 574 adolescents (53% girls, 13 years), conducted in 2017.MethodsWaist circumference was measured, a shuttle run was performed to assess CRF, and a questionnaire was applied. Sex, age, socioeconomic status was reported, and daily duration of ST indicators for television viewing, computer use, videogame playing, and cellphone use, in weekdays and weekend days. Latent class analysis was performed to identify typologies of ST behaviours. Mixed-effects linear regressions were used to test the association of ST clusters with WC and CRF.ResultsParticipants’ WC was 66.9 ± 8 cm and CRF was 39.5 ± 4 ml O₂/kg/min. Four clusters were identified: “Low ST” (25%); “High ST” (20%); “Gamers” (17%); and “High cellphone” (39%). No significant associations were found between ST clusters and WC. Maximum oxygen uptake was higher in those in the “Low ST” cluster compared to the other clusters. No significant interactions for sex were observed.ConclusionsTypologies of ST behaviours do not seem to be related to WC; however, those in the Low ST cluster had higher CRF compared to their peers in the other clusters, suggesting that total ST may be more important for CRF than specific indicators.     

Quantification accuracy of neuro-oncology PET data as a function of emission scan duration in PET/MR compared to PET/CT

ObjectivesTo evaluate and compare the effect of reduced acquisition time, as a surrogate of injected activity, on the PET quantification accuracy in PET/CT and PET/MR imaging.MethodsTwenty min ¹⁸F-FDG phantom measurements and 10 min ¹⁸F-FET brain scans were acquired in a Biograph-True-Point-True-View PET/CT (n = 8) and a Biograph mMR PET/MR (n = 16). Listmode data were repeatedly split into frames of 1 min to 10 min length and reconstructed using two different reconstruction settings of a 3D-OSEM algorithm: with post-filtering (“OSEM”), and without post-filtering but with resolution recovery (“PSF”). Recovery coefficients (RC_max, RC_A50) and standard uptake values (SUV_max, SUV_A50) were evaluated.ResultsRC_max (phantom) and SUV_max (patients) increased significantly when reducing the frame duration. Significantly lower deviations were observed for RC_A50 and SUV_A50, respectively, making them more appropriate to compare PET studies at different number of counts. No statistical significant differences were observed when using post-filtering and reducing the frame time to 4 min (RC_A50, reference 20 min, phantom) and to 3 min (SUV_A50, reference 10 min, patients).ConclusionsFor hybrid aminoacid brain imaging, frame duration (or injected activity) can potentially be reduced to 30% of the standard used in clinical routine without significant changes on the quantification accuracy of the PET images if adequate reconstruction settings and quantitative measures are used. Frame times below 4 min in the NEMA phantom are not advisable to obtain quantitative and reproducible measures.     

Dural invasion of meningiomas adjacent to the tumor margin on Gd-DTPA-enhanced MR images: histopathologic correlation

In intracranial meningiomas a flat, contrast-enhancing, dural structure adjacent to the tumor can occasionally be observed on gadolinium-DTPA-enhanced MR images. We wished to evaluate whether there is a correlation between MR images and meningeal invasion of intracranial meningiomas. The study included 54 patients with intracranial meningioma and the meningeal sign. MR studies included T2-weighted and gadolinium-DTPA-enhanced T1-weighted images in axial, coronal, and sagittal planes. Histopathologic examinations were done on the meningiomas adjacent to the dura mater. The meningeal sign on MRI was observed from 2 up to 35 mm from the main tumor mass in 31 (57 %) of the 54 patients. In 20 of these 31 the histopathologic examination showed tumor invasion, while 11 patients had no tumor invasion but tissue proliferation, hypervascularity, and vascular dilatation. Seven of the 23 meningiomas without the meningeal sign had histologically proven infiltration of the adjacent dura. MR imaging is not able to determine definitive whether or not there is dural infiltration of the meningiomas. In conclusion, resection of the tumor with a wide margin is necessary to achieve complete excision of meningioma and to avoid recurrence. Received 23 July 1997; Revision received 10 October 1997; Accepted 17 October 1997     

Pneumosinus dilatans in anterior skull base meningiomas

Introduction

Skull base meningiomas are often missed on non-contrast CT or MR examinations due to their close proximity to bone and low lesion to brain contrast. The purpose of this study is to illustrate that pneumosinus dilatans can be an indicator of anterior skull base meningiomas.

Methods

A retrospective search of the radiology information system and picture archiving and computing system database was performed. Search terms were “meningioma” in association with “pneumosinus dilatans.” Medical records and imaging studies were reviewed independently by two experienced neuroradiologists and were read in consensus. We recorded the patient age at the time of discovery of the meningioma, main presenting symptom(s), location of the tumor, and imaging characteristics. We also performed a comparative literature search for pneumosinus dilatans and its association with meningiomas.

Results

Ten patients (six women; four men) were identified in whom a meningioma of the anterior skull base was associated with a pneumosinus dilatans. Three patients had multiple meningiomas, so a total of 14 intracranial tumors were identified. Mean age at discovery was 59 years with an age range of ±20 years. All meningiomas were diagnosed by MRI and/or CT.

Conclusion

Pneumosinus dilatans can be a helpful sign to indicate the presence of a meningioma of the anterior skull base.     

The dural tail sign--beyond meningioma

There have been somewhat conflicting reports published about the significance of linear meningeal thickening and enhancement adjacent to peripherally located cranial mass lesions on contrast-enhanced magnetic resonance (MR) images. Most of the authors consider this so-called "dural tail sign" or "flare sign" almost specific for meningioma. This review illustrates the MR imaging findings of a wide spectrum of disorders that show this dural sign. Causes include other extra-axial lesions and also peripherally located intra-axial lesions such as neuromas, chloromas, metastases, lymphoma, gliomas, pituitary diseases, granulomatous disorders, and also cerebral Erdheim-Chester disease. The dural tail sign is not specific to a particular pathological process. Nevertheless, useful conclusions can be drawn from the morphology of the lesion, its enhancement pattern, and its solitary or multifocal presentation. The final diagnosis must be based on cerebrospinal fluid studies or histological studies after biopsy.