Contribution of perfusion-weighted magnetic resonance imaging in the differentiation of meningiomas and other extra-axial tumors: case reports and literature review

Imaging of supratentorial intraventricular masses in children:a pictorial review- part 1

PURPOSE

This article is the first in a two-part series designed to provide a comprehensive overview of the range of supratentorial intraventricular masses observed in children. Our primary objective is to discuss the diverse types of intraventricular masses that originate not only from cells within the choroid plexus but also from other sources.

METHODS

In this article, we review relevant epidemiological data, the current genetics/molecular classification as outlined in the fifth edition of the World Health Organization's Classification of tumours of the Central Nervous System and noteworthy imaging findings. We conduct an exhaustive analysis of primary choroid plexus tumours as well as other conditions such as choroid plexus hyperplasia, choroid plexus cyst, choroid plexus xanthogranuloma, atypical teratoid rhabdoid tumour, meningioma, arteriovenous malformation and metastasis.

RESULTS

We comprehensively evaluated each supratentorial intraventricular mass, providing an in-depth analysis of their unique clinical and histological characteristics. The fifth edition of the World Health Organization Classification of Tumours of the Central Nervous System introduces major modifications. These important changes could potentially have a profound impact on the management strategies and subsequent outcomes of these tumours.

CONCLUSION

Intraventricular masses in children can arise from various sources. Surgical intervention is key for certain supratentorial intraventricular masses in paediatric patients, with preoperative neuroimaging essential to decide the best treatment approach, surgical or otherwise, as some cases may not require surgery.

Preoperative Magnetic Resonance Elastography (MRE) of Skull Base Tumours: A Review

Conventional magnetic resonance imaging (MRI) can detect tumors consistency, but it can't predict tumor stiffness or adherence of the tumor to nearby structures. Magnetic resonance elastography (MRE) is a known non-invasive MRI based imaging technique used to assess the viscoelasticity of the tissues particularly liver fibrosis. This study discussed the importance of preoperative MRE in skull base tumors and the future implications of this new imaging modality. We did review of the English literature (by searching PubMed) regarding the use of MRE in preoperative assessment of skull base tumours stiffness and adherence to surrounding tissues. Recent research demonstrated that MRE can detect the stiffness and adherence of skull base tumors to surrounding structures by recording the spread of mechanical waves in the different tissues. In addition to non-radiation exposure, this technique is fast and can be incorporated into the conventional (MRI) study. MRE can palpate skull base tumours by imaging, allowing the stiffness of the tumour to be assessed. Preoperative assessment of brain tumours consistency, stiffness, and adherence to surrounding tissues is critical to avoid injury of important nearby structures and better preoperative patient counselling regarding surgical approach (endoscopic or open), operative time, and suspected surgical complications. However, the accuracy of MRE is less in small and highly vascular tumors. Also, MRE can't accurately detect tumour-brain adherence, but the new modality (slip-interface imaging) can. Hence, adding MRE to the conventional MRI study may help in preoperative diagnosis and treatment of skull base tumours.

Update on meningioma: Clinical-radiological and radio-pathological correlation

Meningiomas are tumors that originate in the arachnoid villi and are the most common non-glial neoplasm in the central nervous system. The clinical manifestations associated with meningioma depend, fundamentally, on its location. The location in the cerebral convexity is the most frequent, especially in the frontal lobes, manifesting with headache, motor disturbances, seizures and even neurocognitive disorders. There are 15 histologic subtypes of meningioma and three histologic grades. Within these, grades two and three have a worse prognosis and a higher rate of recurrence, as well as a radiological behavior that is generally more aggressive. Although there are some imaging features that can suggest a specific subtype, the definitive diagnosis will always require histological/molecular confirmation.

Extra- and Intracranial Diffuse Large B-Cell Lymphoma (DLBCL) Mimicking Meningioma: A Case Report and Literature Review

Primary central nervous system lymphomas (PCNLSs) are malignant non-Hodgkin lymphomas solely affecting the central nervous system (CNS). Here, we present a rare case of extra- and intracranial manifestation without adjacent calvarial infiltration. We report a 67-year-old woman who presented with right leg paresis and hypoesthesia, facial hypoesthesia, focal epileptic seizures, and an indolent tumor on the left parietal scalp. MRI showed a left paramedian extra- and intracranial contrast-enhancing tumor with infiltration of the superior sagittal sinus, but without osseous infiltration on CT. The tumor was radiologically suspected to be a meningioma and resection was performed. Histological examination, however, revealed a diffuse large B-cell lymphoma (DLBCL). Thus, the patient received adjuvant treatment according to the MATRix protocol. We provide a detailed analysis of this rare case with a focus on preoperative radiological findings and differential diagnoses. To the best of our knowledge, this is one of only four published cases of DLBCL with extra- and intracranial manifestation without bone affection.

Evaluation of the Value of Perfusion-Weighted Magnetic Resonance Imaging in the Differential Diagnosis of Sellar and Parasellar Tumors

The purpose of this study was to assess the value of perfusion-weighted imaging (PWI) in the differential diagnosis of sellar and parasellar tumors, as an additional sequence in the magnetic resonance imaging (MRI) protocol. Analysis was based on a substantial group of subjects and included 124 brain and pituitary MRI examinations with a dynamic susceptibility contrast (DSC) PWI sequence. The following perfusion parameters were determined for the tumors: relative cerebral blood volume (rCBV), relative peak height (rPH) and relative percentage of signal intensity recovery (rPSR). To ensure greater repeatability, each of the aforementioned parameters was calculated as: arithmetic mean of the values of the whole tumor, arithmetic mean of the maximum values on each axial slice within the tumor and maximum values derived from the whole tumor. In our study, we established that meningiomas compared to both non-functional and hormone-secreting pituitary adenomas (pituitary neuroendocrine tumors-PitNET) had significantly higher values of rCBV with cut-off points set at 3.45 and 3.54, respectively (mean rCBV). Additionally, meningiomas presented significantly higher maximum and mean maximum rPH values compared to adenomas. DSC PWI imaging adds significant value to conventional MRI examinations and can be helpful in differentiating equivocal pituitary tumors.

Utility of dynamic susceptibility contrast MRI for differentiation between paragangliomas and meningiomas in the cerebellopontine angle and jugular foramen region

PURPOSE

Differentiation of paragangliomas and meningiomas can be a challenge. This study aimed to assess the utility of dynamic susceptibility contrast perfusion MRI (DSC-MRI) to distinguish paragangliomas from meningiomas.

METHODS

This retrospective study included 40 patients with paragangliomas and meningiomas in the cerebellopontine angle and jugular foramen region between March 2015 and February 2022 in a single institution. Pretreatment DSC-MRI and conventional MRI were performed in all cases. Normalized relative cerebral blood volume (nrCBV), relative cerebral blood flow (nrCBF), relative mean transit time (nrMTT), and time to peak (nTTP) as well as conventional MRI features were compared between the 2 tumor types and between meningioma subtypes as appropriate. Receiver operating characteristic curve and multivariate logistic regression analysis were performed.

RESULTS

Twenty-eight meningiomas including 8 WHO grade II meningiomas (12 males, 16 females; median age 55 years) and 12 paragangliomas (5 males, 7 females; median age 35 years) were included in this study. Paragangliomas had a higher rate of cystic/necrotic changes (10/12 vs 10/28; P = 0.014), a higher rate of internal flow voids (9/12 vs 8/28; P = 0.013), higher nrCBV (median 9.78 vs 6.64; P = 0.04), and shorter nTTP (median 0.78 vs 1.06; P < 0.001) than meningiomas. There was no difference in conventional imaging features and DSC-MRI parameters between meningioma subtypes. nTTP was identified as the most significant parameter for the 2 tumor types in the multivariate logistic regression analysis (P = 0.009).

CONCLUSIONS

In this small retrospective study, DSC-MRI perfusion differences were observed between paragangliomas and meningiomas, but not between grade I and II meningiomas.

The Vestibulocochlear Nerve: Anatomy and Pathology

The vestibulocochlear nerve is the eighth cranial nerve, entering the brainstem in the medullopontine sulcus after crossing the internal auditory canal and cerebellopontine angle cistern. It is a purely sensitive nerve, originating from the Scarpa's and spiral ganglions, responsible for balance and hearing. It has 6 nuclei located in the lower pons. Magnetic resonance imaging (MRI) is useful for evaluating the vestibulocochlear nerve, although computed tomography may have a complementary role in assessing bone lesions. A heavily T2-weighted sequence, such as fast imaging employing steady-state acquisition (FIESTA) or constructive interference steady state (CISS), is crucial in imaging exams to depict the canalicular and cisternal segments of the vestibulocochlear nerve, as well as the fluid signal intensity in the membranous labyrinth. The vestibulocochlear nerve can be affected by several diseases, such as congenital malformations, trauma, inflammatory or infectious diseases, vascular disorders, and neoplasms. The purpose of this article is to review the vestibulocochlear nerve anatomy, discuss the best MRI techniques to evaluate this nerve and demonstrate the imaging aspect of the main diseases that affect it.

Tumors of Choroid Plexus and Other Ventricular Tumors

Tumors arising inside the ventricular system are rare but represent a difficult diagnostic and therapeutic challenge. They usually are diagnosed when reaching a big volume and tend to affect young children. There is a wide broad of differential diagnoses with significant variability in anatomical aspects and tumor type. Differential diagnosis in tumor type includes choroid plexus tumors (papillomas and carcinomas), ependymomas, subependymomas, subependymal giant cell astrocytomas (SEGAs), central neurocytomas, meningiomas, and metastases. Choroid plexus tumors, ependymomas of the posterior fossa, and SEGAs are more likely to appear in childhood, whereas subependymomas, central neurocytomas, intraventricular meningiomas, and metastases are more frequent in adults. This chapter is predominantly focused on choroid plexus tumors and radiological and histological differential diagnosis. Treatment is discussed in the light of the modern acquisition in genetics and epigenetics of brain tumors.

Imaging Characteristics of Meningiomas

Contemporary neuroimaging of meningiomas has largely relied on computed tomography, and more recently magnetic resonance imaging. While these modalities are frequently used in nearly all clinical settings where meningiomas are treated for the routine diagnosis and follow-up of these tumors, advances in neuroimaging have provided novel opportunities for prognostication and treatment planning (including both surgical planning and radiotherapy planning). These include perfusion MRIs, and positron emission tomography (PET) imaging modalities. Here we will summarize the contemporary uses for neuroimaging in meningiomas, and future applications of novel, cutting edge imaging techniques that may be routinely implemented in the future to enable more precise treatment of these challenging tumors.

Central neurocytoma-positive and differential diagnosis: An example through a case report

Central neurocytoma is a rare intraventricular tumor, occurring typically in the lateral ventricle of young adults. It is considered as a neuronal-glial benign tumor with favorable prognosis. Imaging is a cornerstone allowing the accurate preoperative diagnosis on the basis of several characteristic features. We report the case of a 31-year-old man who has been complaining of progressive headaches and in whom brain magnetic resonance imaging revealed a central neurocytoma. We remind then, through a literature review, the main criteria to set the diagnosis of this tumor and rule out the other possible diagnoses.

Dural lymphoma misdiagnosed as subdural hematoma following head trauma after an episode of syncope

Primary dural lymphoma is a rare subtype of primary central nervous system lymphoma. Primary dural lymphoma may be radiologically misdiagnosed as it shares similar imaging characteristics with several pathologies, including meningiomas and subdural or epidural hematomas. We present a patient who was originally diagnosed with a subdural hematoma following a syncopal episode on computed tomography. Follow-up magnetic resonance imaging of the brain demonstrated heterogeneously enhancing dural-based mass overlying the left frontoparietal convexity associated with bidirectional dural tails, suggestive of a malignant meningioma. Neurosurgical histopathology revealed marginal zone B-cell lymphoma. This case represents the potential difficulty in diagnosing primary dural lymphoma, especially in the setting of uncertain clinical history and obscured imaging features.

Intracranial paragangliomas versus schwannomas: Role of dynamic susceptibility contrast perfusion and diffusion MRI

BACKGROUND AND PURPOSE

Differentiating paragangliomas from schwannomas and distinguishing sporadic from neurofibromatosis type 2 (NF 2)-related schwannomas is challenging but clinically important. This study aimed to assess the utility of dynamic susceptibility contrast perfusion MRI (DSC-MRI) and diffusion-weighted imaging (DWI) in discriminating infratentorial extra-axial schwannomas from paragangliomas and NF2-related schwannomas.

METHODS

This retrospective study included 41 patients diagnosed with paragangliomas, sporadic schwannomas, and NF2-related schwannomas in the infratentorial extra-axial space between April 2013 and August 2021. All cases had pretreatment DSC-MRI and DWI. Normalized mean apparent diffusion coefficient (nADCmean), normalized relative cerebral blood volume (nrCBV), and normalized relative cerebral blood flow (nrCBF) were compared between paragangliomas and schwannomas and between sporadic and NF2-related schwannomas as appropriate.

RESULTS

nrCBV and nrCBF were significantly higher in paragangliomas than in sporadic/NF2-related schwannomas (nrCBV: median 11.5 vs. 1.14/3.74; p < .001 and .004, nrCBF: median 7.43 vs. 1.13/2.85; p < .001 and .007, respectively), while nADCmean were not. The corresponding diagnostic performances were area under the curves (AUCs) of .99/.92 and 1.0/.90 with cutoffs of 2.56/4.22 and 1.94/3.36, respectively. nADCmean were lower, and nrCBV and nrCBF were higher in NF2-related than in sporadic schwannomas (nADCmean: median 1.23 vs. 1.58, nrCBV: median 3.74 vs. 1.14, nrCBF: median 2.85 vs. 1.13; all p < .001), and the corresponding diagnostic performances were AUCs of .93, .91, and .95 with cutoffs of 1.37, 2.63, and 2.48, respectively.

CONCLUSIONS

DSC-MRI and DWI both can aid in differentiating paragangliomas from schwannomas and sporadic from NF2-related schwannomas.

FDG avid cerebellar atypical meningioma masquerading as solitary brain metastases in a recently diagnosed breast malignancy: a toss between MR and CT

Background

SUV Max is a glycolytic index obtained from PET imaging, relates to tumour cell proliferation. FDG uptake (i.e. SUV max) is found to be high in aggressive tumours and is used to identify malignant from benign pathologies. Meningiomas are intracranial tumours which display varying grades of FDG avidity based on its biological aggressiveness. Benign grade I meningiomas are FDG non-avid, while the rest of the typical and atypical meningiomas show varying degrees of FDG avidity. Uptake of FDG can be high in certain infectious and inflammatory brain etiologies and pose a diagnostic challenge in differentiating benign brain lesions from neoplasms. MRI is the preferred modality for accurately identifying meningiomas, providing superior contrast differentiation and its ability to differentiate extra-axial from intra-axial brain lesions. CT is said to be superior in specific types of meningioma where there is calcification and adjacent changes in calvarium. Although typical meningiomas have characteristic MRI features, care must be taken to avoid misleading diagnosis between brain tumours and atypical meningiomas.

Case presentation

We are presenting a recently diagnosed case of invasive breast carcinoma (Ca) referred for staging by PET/MR imaging. Based on atypical DWI and ADC map findings, MRI falsely reported an atypical meningioma as a brain metastasis. Abnormal intense FDG uptake was noted in a well-defined homogeneously enhancing mass lesion in posterior fossa in left paramedian aspect and broad base to left transverse sinus protruding into left cerebellar hemisphere. Atypical meningioma Grade III, i.e. papillary meningioma was later histologically proven.

Conclusions

We wish to highlight the inconsistency of DWI and ADC map MR findings in papillary meningioma masquerading as solitary brain metastases in a Ca breast patient on 18F FDG PET/MR imaging. From an imaging standpoint, it is important to recognize the variable and pleomorphic features exhibited by meningiomas in MR based on atypical location, histological subtypes, and biologic behaviours. Further FDG PET was incremental in displaying a high SUV max indicating biologic aggressiveness of lesion and correlating with the CT diagnosis of papillary meningioma.

Precise discrimination between meningiomas and schwannomas using time-to-signal intensity curves and percentage signal recoveries obtained from dynamic susceptibility perfusion imaging

BACKGROUND AND PURPOSE

Meningiomas and schwannomas are common extra-axial brain tumors. Discrimination is challenging in some locations when characteristic imaging features are absent. This study investigated the accuracy of percentage signal recoveries obtained from dynamic susceptibility contrast perfusion imaging (DSC-PI) in discriminating meningiomas and schwannomas.

MATERIAL AND METHODS

Retrospective database research was conducted. Sixty nine meningioma and 15 schwannoma having DSC-PI between January 2016 and February 2020 were included. Time to signal intensity curves (TSIC) were analyzed and grouped as T1-dominant leakage, T2*-dominant leakage and return to baseline. Relative cerebral blood volume (rCBV), relative mean transit time (rMTT), percentage signal recovery 1 (PSR 1) and PSR 2 values were calculated. The differences between the groups were investigated. Receiver operating characteristic curves were operated.

RESULTS

rCBV, rMTT, PSR 1 and PSR 2 values were statistically different between meningiomas and schwannomas. PSR 2 provided the best discrimination. With the cut off value of 1.08 for PSR 2, meningiomas and schwannomas were differentiated with 95.7% sensitivity and 93.3% specificity. TSICs were also different between two groups. Most of meningiomas showed T2*-dominant leakage (78.2%), whereas most of shwannomas showed T1-dominant leakage (93.3%).

CONCLUSION

DSC-PI is a useful imaging tool for non-invasive discrimination of meningiomas and schwannomas. Particularly, percentage signal recoveries discriminates meningiomas and schwannomas with high sensitivity and specificity.

Additional diagnostic role of MRI spectroscopy, diffusion and susceptibility imaging in differentiation of CPA masses: our experience with emphasis on schwannomas and meningiomas

Background

CPA masses are uncommon lesions and usually have quite distinctive imaging features. Still, diagnosis can be challenging in some cases, carrying a significant impact on the choice of treatment and surgical approach. The purpose of this study was to validate the usefulness of MRI spectroscopy, diffusion, and susceptibility in the characterization of CPA masses with the emphasis on the two commonest lesions: schwannomas and meningiomas.

Results

The study included a total of 27 cases: schwannomas (n = 12), meningiomas (n = 7), epidermoid cysts (n = 2), two chondrosarcomas (n = 2), arachnoid cyst (n = 1), glomus tumor (n = 1), a meningeal metastasis (n = 1), and an endolymphatic sac tumor (n = 1). DWI revealed: eight lesions showed low ADC (<1 × 10−3 mm2/s), 15 lesions with intermediate ADC values (1–1.8 × 10−3 mm2/s), and 4 lesions had high ADC (>1.8 × 10−3 mm2/s.) Meningiomas showed low to intermediate ADC values while schwannomas showed intermediate to high ADC values. A cut-off ADC value of (1 × 10−3 mm2/s) is statistically significant in the differentiation of meningioma from schwannoma. A myoinositol peak was in all 12 schwannomas and single meningioma while 6 meningiomas displayed alanine peak, with a very good statistical significance. Remaining lesions revealed non-specific spectra. SWI made in 18 lesions revealed signal voids in three schwannomas and glomus.

Conclusions

Though MRI features of CPA masses are distinctive in most clinical settings; MRI spectroscopy, diffusion, and susceptibility can provide highly informative additional data in problematic cases. An intermediate to high ADC value plus myoinositol peak and signal voids of micro-bleeds are highly suggestive of schwannomas. This is in contrary to meningiomas displaying low to intermediate ADC and an alanine peak with no micro-bleeds. The less common lesions revealed non-specific data.

Recent advances in MRI of the head and neck, skull base and cranial nerves: new and evolving sequences, analyses and clinical applications

MRI is an invaluable diagnostic tool in the investigation and management of patients with pathology of the head and neck. However, numerous technical challenges exist, owing to a combination of fine anatomical detail, complex geometry (that is subject to frequent motion) and susceptibility effects from both endogenous structures and exogenous implants. Over recent years, there have been rapid developments in several aspects of head and neck imaging including higher resolution, isotropic 3D sequences, diffusion-weighted and diffusion-tensor imaging as well as permeability and perfusion imaging. These have led to improvements in anatomic, dynamic and functional imaging. Further developments using contrast-enhanced 3D FLAIR for the delineation of endolymphatic structures and black bone imaging for osseous structures are opening new diagnostic avenues. Furthermore, technical advances in compressed sensing and metal artefact reduction have the capacity to improve imaging speed and quality, respectively. This review explores novel and evolving MRI sequences that can be employed to evaluate diseases of the head and neck, including the skull base.

Utility of Percentage Signal Recovery and Baseline Signal in DSC-MRI Optimized for Relative CBV Measurement for Differentiating Glioblastoma, Lymphoma, Metastasis, and Meningioma

BACKGROUND AND PURPOSE

The percentage signal recovery in non-leakage-corrected (no preload, high flip angle, intermediate TE) DSC-MR imaging is known to differ significantly for glioblastoma, metastasis, and primary CNS lymphoma. Because the percentage signal recovery is influenced by preload and pulse sequence parameters, we investigated whether the percentage signal recovery can still differentiate these common contrast-enhancing neoplasms using a DSC-MR imaging protocol designed for relative CBV accuracy (preload, intermediate flip angle, low TE).

MATERIALS AND METHODS

We retrospectively analyzed DSC-MR imaging of treatment-naïve, pathology-proved glioblastomas (n = 14), primary central nervous system lymphomas (n = 7), metastases (n = 20), and meningiomas (n = 13) using a protocol designed for relative CBV accuracy (a one-quarter-dose preload and single-dose bolus of gadobutrol, TR/TE = 1290/40 ms, flip angle = 60° at 1.5T). Mean percentage signal recovery, relative CBV, and normalized baseline signal intensity were compared within contrast-enhancing lesion volumes. Classification accuracy was determined by receiver operating characteristic analysis.

RESULTS

Relative CBV best differentiated meningioma from glioblastoma and from metastasis with areas under the curve of 0.84 and 0.82, respectively. The percentage signal recovery best differentiated primary central nervous system lymphoma from metastasis with an area under the curve of 0.81. Relative CBV and percentage signal recovery were similar in differentiating primary central nervous system lymphoma from glioblastoma and from meningioma. Although neither relative CBV nor percentage signal recovery differentiated glioblastoma from metastasis, mean normalized baseline signal intensity achieved 86% sensitivity and 50% specificity.

CONCLUSIONS

Similar to results for non-preload-based DSC-MR imaging, percentage signal recovery for one-quarter-dose preload-based, intermediate flip angle DSC-MR imaging differentiates most pair-wise comparisons of glioblastoma, metastasis, primary central nervous system lymphoma, and meningioma, except for glioblastoma versus metastasis. Differences in normalized post-preload baseline signal for glioblastoma and metastasis, reflecting a snapshot of dynamic contrast enhancement, may motivate the use of single-dose multiecho protocols permitting simultaneous quantification of DSC-MR imaging and dynamic contrast-enhanced MR imaging parameters.

Usefulness of Histogram-Profile Analysis in Ring-Enhancing Intracranial Lesions

BACKGROUND

Several intracranial pathologies present as a ring-enhancing lesion on conventional magnetic resonance imaging (MRI), creating diagnostic difficulty. We studied the characteristics of the anatomical border of gadolinium enhancement on T1-weighted imaging (WI) and hypointensity on T2WI to employ a simple technique of histogram-profile analysis of MRI for differentiation of various ring-enhancing intracranial lesions.

METHODS

After approval from the institutional review board, preoperative MRI (T2WI, postcontrast T1WI) scans were analyzed retrospectively in 18 patients with histologically confirmed brain abscess, 66 glioblastomas, 46 brain-metastases, and 16 tumefactive multiple sclerosis (MS). T2WI and postcontrast T1WI were overlapped, and histogram-profile analysis was performed with in-house image-fusion software. The pattern of differential-peaks in histogram-profile was assessed visually. Kaplan-Meier survival analysis incorporating histogram-profile patterns was performed in patients with glioblastoma.

RESULTS

The histogram-profile study revealed 4 distinct patterns. Pattern 1 showed no differential T2-hypointensity trough, pattern 2 had T2-hypointensity trough inside, whereas pattern 3 had T2-hypointensity trough overlapping the enhanced margin. Pattern 4 had T2-hypointensity trough immediately external to the enhanced margin. Pattern 1 was specific for tumefactive MS (93.3%), whereas pattern 4 was specific for glioblastoma (40.7%). Pattern 4 glioblastoma was subdivided into rim (T2-hypointensity ≥50% of circumference of contrast-enhanced tumor) and arc (T2-hypointensity <50% of circumference of contrast-enhanced tumor). Pattern 4 glioblastoma was further subdivided into group A (edema: T2-hyperintensity ≥50% of circumference of contrast-enhanced tumor) and group B (less edema: T2-hyperintensity <50% of circumference of contrast-enhanced tumor). Patients with pattern 3 glioblastoma (37.6%) had better survival compared with others (P = 0.0341) and pattern 4B had decreased survival compared with pattern 4A (P = 0.0001) and others (P = 0.0003).

CONCLUSIONS

Tumefactive MS and a subset of glioblastomas show specific patterns in histogram-profile analysis. The difference in anatomical border also determines difference in survival in glioblastoma. Histogram-profile analysis is a simple and efficient technique to differentiate these pathologies.

Noninvasive Differentiation of Meningiomas and Dural Metastases Using Intratumoral Vascularity Obtained by Arterial Spin Labeling

Purpose

Using conventional magnetic resonance imaging (MRI) techniques, the imaging features of meningiomas and dural metastases overlap and a differentiation between these tumor entities therefore remains difficult, particularly in patients with a known primary neoplasm. The purpose of this study was to explore the potential role of normalized vascular intratumoral signal intensity values (nVITS) obtained from pulsed arterial spin labeling (PASL) to differentiate between meningiomas and dural metastases.

Methods

In this study PASL was performed in 46 patients with meningiomas (n = 30) and dural metastases (n = 16) on a 3T scanner, in addition to the routine diagnostic imaging protocol. The ratio between the vascular signal intensity of the tumor and the contralateral normal white matter obtained by PASL images was defined as nVITS.

Results

Meningiomas showed significantly higher nVITS values compared to dural metastases (p < 0.001). The optimal nVITS cut-off value to differentiate between the 2 tumor entities was 1.989, with 100% sensitivity and 81.2% specificity.

Conclusion

The nVITS values obtained by PASL provide a fast and noninvasive MRI technique with which to differentiate between meningiomas and dural metastases in a routine clinical setting based on tumor vascularity.

Dural masses: meningiomas and their mimics

Meningiomas are the most common dural tumour. They are regularly being seen as an incidental finding on brain imaging and treated conservatively. However, there are many other dural masses which mimic their appearances, including primary neoplastic processes, metastases, granulomatous diseases and infection. While some of these are rare, others such as metastases and tuberculosis arise relatively frequently in practice. Although not pathognomonic, key features which increase the probability of a lesion being a meningioma include intralesional calcifications, skull hyperostosis, local dural enhancement and increased perfusion. It is important to have an awareness of these entities as well as their main imaging findings, as they have a wide range of prognoses and differing management strategies. This review outlines several of the most important mimics along with their imaging findings on both standard and advanced techniques with key features which may be used to help differentiate them from meningiomas.

The role of diffusion and perfusion magnetic resonance imaging in differentiation of haemangioblastomas and pilocytic astrocytomas

Purpose

Haemangioblastomas (HABLs) and pilocytic astrocytomas (PAs) are brain tumours presenting similar appearance and location in conventional magnetic resonance (MR) imaging. The purpose of our study was to determine whether a detailed analysis of diffusion (DWI) and perfusion (PWI) characteristics can be useful in preoperative differentiation of these tumours.

Material and methods

The study group consisted of biopsy proven six HABLs and six PAs, which underwent preoperative standard MR examinations including PWI and DWI. In PWI relative cerebral blood volume (rCBV) and the shape of perfusion curves (parameters of peak height - rPH and percentage of signal recovery - rPSR) were analysed. All perfusion parameters were measured for the entire tumour core (mean rCBV, mean rPH, mean rPSR) and in regions with maximal values (max rCBV, max rPH, max rPSR). In DWI parameters of apparent diffusion coefficient (ADC) from the entire tumour core (mean ADC) and in regions with minimal values (min ADC) were evaluated.

Results

Compared to PAs, HABLs presented significantly higher rCBV and rPH values and lower mean rPSR value. PAs showed significantly lower rCBV and rPH values and higher mean rPSR value. Mean rCBV showed no overlap in the values between HABLs and PAs, and thus it provided the highest accuracy in differentiating between them. Max rPSR, mean ADC, and min ADC did not show any significant differences.

Conclusions

High rCBV values and deep perfusion curves with only partial return to the baseline are characteristic features of HABLs differentiating them from PAs, which show lower rCBV values and perfusion curves overshooting the baseline. Diffusion parameters are not useful in differentiation of these tumours.

Diagnostic challenges in meningioma

Advances in molecular profiling and the application of advanced imaging techniques are currently refreshing diagnostic considerations in meningioma patients. Not only technical refinements but also sophisticated histopathological and molecular studies have the potential to overcome some of the challenges during meningioma management. Exact tumor delineation, assessment of tumor growth, and pathophysiological parameters were recently addressed by "advanced" MRI and PET. In the field of neuropathology, high-throughput sequencing and DNA methylation analysis of meningioma tissue has greatly advanced the knowledge of molecular aberrations in meningioma patients. These techniques allow for more reliable prediction of the biological behavior and clinical course of meningiomas and subsequently have the potential to guide individualized meningioma therapy. However, higher costs and longer duration of full molecular work-up compared with histological assessment may delay the implementation into clinical routine.This review highlights the diagnostic challenges of meningiomas from both the neuroimaging as well as the neuropathological side and presents the latest scientific achievements and studies potentially helping in overcoming these challenges. It complements the recently proposed European Association of Neuro-Oncology guidelines on treatment and diagnosis of meningiomas by integrating data on nonstandard imaging and molecular assessments most likely impacting the future.

A semi-automated volumetric software for segmentation and perfusion parameter quantification of brain tumors using 320-row multidetector computed tomography: a validation study

PURPOSE

We developed a semi-automated volumetric software, NPerfusion, to segment brain tumors and quantify perfusion parameters on whole-brain CT perfusion (WBCTP) images. The purpose of this study was to assess the feasibility of the software and to validate its performance compared with manual segmentation.

METHODS

Twenty-nine patients with pathologically proven brain tumors who underwent preoperative WBCTP between August 2012 and February 2015 were included. Three perfusion parameters, arterial flow (AF), equivalent blood volume (EBV), and Patlak flow (PF, which is a measure of permeability of capillaries), of brain tumors were generated by a commercial software and then quantified volumetrically by NPerfusion, which also semi-automatically segmented tumor boundaries. The quantification was validated by comparison with that of manual segmentation in terms of the concordance correlation coefficient and Bland-Altman analysis.

RESULTS

With NPerfusion, we successfully performed segmentation and quantified whole volumetric perfusion parameters of all 29 brain tumors that showed consistent perfusion trends with previous studies. The validation of the perfusion parameter quantification exhibited almost perfect agreement with manual segmentation, with Lin concordance correlation coefficients (ρ _c) for AF, EBV, and PF of 0.9988, 0.9994, and 0.9976, respectively. On Bland-Altman analysis, most differences between this software and manual segmentation on the commercial software were within the limit of agreement.

CONCLUSIONS

NPerfusion successfully performs segmentation of brain tumors and calculates perfusion parameters of brain tumors. We validated this semi-automated segmentation software by comparing it with manual segmentation. NPerfusion can be used to calculate volumetric perfusion parameters of brain tumors from WBCTP.

Perfusion magnetic resonance imaging provides additional information as compared to anatomical imaging for decision-making in vestibular schwannoma

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DSC/ASL-MRI can be acquired in growing VS with sufficient image quality.

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In most patients DSC and ASL techniques provide similar qualitative scores.

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These techniques can be of importance in future decision-making.

Objective

The added value of perfusion MRI for decision-making in vestibular schwannoma (VS) patients is unknown. MRI offers two perfusion methods: the first employing contrast agent (dynamic susceptibility contrast (DSC)-MRI) that provides information on cerebral blood volume (CBV) and cerebral blood flow (CBF), the second by magnetic labeling of blood (arterial spin labeling (ASL)-MRI), providing CBF-images. The goal of the current study is to investigate whether DSC and ASL perfusion MRI provides complimentary information to current anatomical imaging in treatment selection process of VS.

Methods

Nine patients with growing VS with extrameatal diameter >9 mm were included (>2 mm/year and 20% volume expansion/year) and one patient with 23 mm extrameatal VS without growth. DSC and ASL perfusion MRI were obtained on 3 T MRI. Perfusion in VS was scored as hyperintense, hypointense or isointense compared to the contralateral region.

Results

Seven patients showed hyperintense signal on DSC and ASL sequences. Three patients showed iso- or hypointense signal on at least one perfusion map (1 patient hypointense on both DSC-MRI and ASL; 1 patient isointense on DSC-CBF; 1 patient isointense on ASL). All patients showed enhancement on post-contrast T1 anatomical scan.

Conclusion

Perfusion MR provides additional information compared to anatomical imaging for decision-making in VS.

Imaging of skull base pathologies: Role of advanced magnetic resonance imaging techniques

Imaging plays a vital role in evaluation of skull base pathologies as this region is not directly accessible for clinical evaluation. Computerized tomography (CT) and magnetic resonance imaging (MRI) have played complementary roles in the diagnosis of the various neoplastic and non-neoplastic lesions of the skull base. However, CT and conventional MRI may at times be insufficient to correctly pinpoint the accurate diagnosis. Advanced MRI techniques, though difficult to apply in the skull base region, in conjunction with CT and conventional MRI can however help in improving the diagnostic accuracy. This article aims to highlight the importance of advanced MRI techniques like diffusion-weighted imaging, susceptibility-weighted imaging, perfusion-weighted imaging, and MR spectroscopy in differentiation of various lesions involving the skull base.

Choroid Plexus Neoplasms: Toward a Distinction between Carcinoma and Papilloma Using Arterial Spin-Labeling

Pediatric choroid plexus papillomas and carcinomas are highly vascularized neoplasms, which are difficult to distinguish with conventional imaging. We aimed to analyze the diagnostic accuracy of PWI, by using both pseudocontinuous arterial spin-labeling and DSC-PWI. We reviewed the PWI of 13 children with choroid plexus neoplasms (7 papillomas and 6 carcinomas). We quantified CBF, relative CBF, and relative CBV in each lesion and compared papillomas and carcinomas. Relative CBF values by using arterial spin-labeling were significantly higher for carcinomas (P = .028). The median value of relative CBF was 1.7 (range, 1.4-1.9) for carcinomas and 0.4 (range, 0.3-0.6) for papillomas. The CBF median value was 115 mL/min/100 g (range, 90-140 mL/min/100 g) for carcinomas and 41 mL/min/100 g (range, 10-73 mL/min/100 g) for papillomas (P = .056). Measures with DSC-PWI were more variable and not significantly different (P = .393). Arterial spin-labeling is a promising technique to differentiate choroid plexus carcinomas and papillomas.

Intracranial Lesions with Low Signal Intensity on T2-weighted MR Images - Review of Pathologies

In this article we presented intracranial pathological substances and lesions with low signal intensity on T2-weighted images. Eight groups of substances were discussed i.e. 1. Gadolinium-based contrast materials, 2. hemoglobin degradation products 3. melanin, 4. mucous- or protein-containing lesions, 5. highly cellular lesions, 6. lesions containing mineral substances such as: calcium, copper and iron, 7. turbulent and rapid blood or CSF flow 8. air-containing spaces. Appropriate interpretation of signal intensity as well as analysis of lesion location and clinical symptoms enable a correct choice of a further diagnostic algorithm or, in many cases, final diagnosis based exclusively on an MRI examination.

Central nervous system lymphoma in a 3-year-old male suffering from a severe juvenile xanthogranuloma - the usefulness of perfusion weighted imaging and diffusion weighted imaging in the diagnostics of pediatric brain tumors

Background

Primary Central Nervous System Lymphomas (PCNSLs) are rare, malignant brain tumors derived from lymphocytes B. Juvenile xanthogranuloma (JXG) is a non-Langerhans histiocytic cell disorder in children which mostly affects the skin. Rare fatalities have been reported in extracutaneous manifestation. Brain magnetic resonance imaging (MRI) is a method of choice in the diagnostics of all neoplastic CNS lesions. Perfusion weighted imaging (PWI) and diffusion weighted imaging (DWI) allow for more detailed analysis of brain tumors including the rate of neoangiogenesis and cellularity. We presented a pediatric patient suffering from JXG with CNS involvement and the role of brain MRI including DWI and PWI in the evaluation of brain focal lesions.

Case Report

A 3-year-old male with severe JXG underwent two stem cell transplantations with a development of neurological complications. The patient underwent emergency CT and MRI which revealed a non-specific enhancing focal brain lesion. In DWI it showed restricted diffusion while PWI revealed low values of rCBV and the signal intensity curve returning above the baseline level. Advanced MRI techniques such as DWI and PWI suggested PCNSL. Stereotactic biopsy confirmed PCNSL due to Ebstein-Barr virus reactivation.

Conclusions

The use of advanced MRI sequences is important to differentiate brain lesions in pediatric patients. The use of PWI and DWI facilitated the diagnosis of PCNSL. It is important to remember that PCNSLs show a very typical pattern of changes visualized with MRI such as: usually strong homogenous enhancement, restricted diffusion and low perfusion.

Surgical resection of sporadic and hereditary hemangioblastoma: Our 10-year experience and a literature review

Background:

Hemangioblastomas (HBLs) are benign neoplasms that contribute to 1-2.5% of intracranial tumors and 7-12% of posterior fossa lesions in adult patients. HBLs either evolve hereditarily in association with von Hippel–Lindau disease (vHL) or, more prevalently, as solitary sporadic tumors. Only few authors have reported on the clinical presentation and the neurological outcome of HBL.

Methods:

We retrospectively analyzed the clinical, radiological, surgical, and histopathologic records of 24 consecutive patients (11 men, 13 women; mean age 51.3 years) with HBL of the posterior cranial fossa, who had been treated at our center between 2001 and 2012. We reviewed the current literature, and discussed our findings in the context of previous publications on HBL. The study protocol was approved by the local ethics committee (14-101-0070).

Results:

Mean time to diagnosis was 14 weeks. The extent of resection (EOR) was total in 20 and near total in 4 patients. Four patients required revision within 24 h because of relevant postoperative bleeding. One patient died within 14 days. One patient required permanent shunting. At discharge, 75% of patients [n = 18, modified Rankin scale (mRS) 0-1] showed no or at least resolved symptoms. Mean follow-up was 21 months. Two recurrences were detected during follow-up.

Conclusions:

In comparison to other benign entities of the posterior fossa, time to diagnosis was significantly shorter for HBL. This finding indicates the rather aggressive biological behavior of these excessively vascularized tumors. In our series, however, the rate of complete resection was high, and morbidity and mortality rates were within the reported range.

Imaging of brain tumors

Neuroimaging plays a crucial role in diagnosis of brain tumors and in the decision-making process for therapy. Functional imaging techniques can reflect cellular density (diffusion imaging), capillary density (perfusion techniques), and tissue biochemistry (magnetic resonance [MR] spectroscopy). In addition, cortical activation imaging (functional MR imaging) can identify various loci of eloquent cerebral cortical function. Combining these new tools can increase diagnostic specificity and confidence. Familiarity with conventional and advanced imaging findings facilitates accurate diagnosis, differentiation from other processes, and optimal patient treatment. This article is a practical synopsis of pathologic, clinical, and imaging spectra of most common brain tumors.

Microvascular decompression surgery: surgical principles and technical nuances based on 4000 cases

BACKGROUND

As an etiological treatment of trigeminal neuralgia (TN) and hemifacial spasm (HFS), microvascular decompression (MVD) has been popularized around the world. However, as a functional operation in the cerebellopontine angle (CPA), this process can be risky and the postoperative outcomes might not be good enough sometimes.

OBJECTIVE

In order to obtain a better result with less complication, this surgery should be further addressed.

METHODS

With experience of more than 4000 MVDs, we have gained knowledge about the operative technique. Through abundant intraoperative photos, each step of the procedure was demonstrated in detail and the surgical strategy was focused.

RESULTS

The principle of MVD is to separate the nerve-vessel confliction rather than isolate it with prostheses. A prompt identification of the conflict site is important, which hinges on a good exposure. A satisfactory working space can be established by an appropriate positioning of the patient's head and a proper craniectomy as well as a rational approach. A sharp dissection of arachnoids leads to a maximal visualization of the entire intracranial course of the nerve root. All the vessels contacting the trigeminal or facial nerve should be treated. Intraoperative electrophysiological mentoring is helpful to distinguish the offending artery for hemifacial cases.

CONCLUSION

MVD is an effective treatment for the patient with TN or HFS. Immediate relief can be achieved by an experienced neurosurgeon with good knowledge of regional anatomy. A safe surgery is the tenet of MVD, and accordingly, no single step of the procedure should be ignored.

Comparison of 18F-FET PET and perfusion-weighted MR imaging: a PET/MR imaging hybrid study in patients with brain tumors

PET using O-(2-(18)F-fluoroethyl)-L-tyrosine ((18)F-FET) provides important diagnostic information in addition to that from conventional MR imaging on tumor extent and activity of cerebral gliomas. Recent studies suggest that perfusion-weighted MR imaging (PWI), especially maps of regional cerebral blood volume (rCBV), may provide similar diagnostic information. In this study, we directly compared (18)F-FET PET and PWI in patients with brain tumors.

METHODS

Fifty-six patients with gliomas were investigated using static (18)F-FET PET and PWI. For comparison, 8 patients with meningiomas were included. We generated a set of tumor and reference volumes of interest (VOIs) based on morphologic MR imaging and transferred these VOIs to the corresponding (18)F-FET PET scans and PWI maps. From these VOIs, tumor-to-brain ratios (TBR) were calculated, and normalized histograms were generated for (18)F-FET PET and rCBV maps. Furthermore, in rCBV maps and in (18)F-FET PET scans, tumor volumes, their spatial congruence, and the distance between the local hot spots were assessed.

RESULTS

For patients with glioma, TBR was significantly higher in (18)F-FET PET than in rCBV maps (TBR, 2.28 ± 0.99 vs. 1.62 ± 1.13; P < 0.001). Histogram analysis of the VOIs revealed that (18)F-FET scans could clearly separate tumor from background. In contrast, deriving this information from rCBV maps was difficult. Tumor volumes were significantly larger in (18)F-FET PET than in rCBV maps (tumor volume, 24.3 ± 26.5 cm(3) vs. 8.9 ± 13.9 cm(3); P < 0.001). Accordingly, spatial overlap of both imaging parameters was poor (congruence, 11.0%), and mean distance between the local hot spots was 25.4 ± 16.1 mm. In meningioma patients, TBR was higher in rCBV maps than in (18)F-FET PET (TBR, 5.33 ± 2.63 vs. 2.37 ± 0.32; P < 0.001) whereas tumor volumes were comparable.

CONCLUSION

In patients with cerebral glioma, tumor imaging with (18)F-FET PET and rCBV yields different information. (18)F-FET PET shows considerably higher TBRs and larger tumor volumes than rCBV maps. The spatial congruence of both parameters is poor. The locations of the local hot spots differ considerably. Taken together, our data show that metabolically active tumor tissue of gliomas as depicted by amino acid PET is not reflected by rCBV as measured with PWI.

Unique presentation of cerebellopontine angle choroid plexus papillomas: case report and review of the literature

Objectives We present the case of a choroid plexus papilloma (CPP) in the cerebellopontine angle (CPA), describe the different appearances of CPPs with a variety of imaging techniques, and discuss the differential diagnosis of CPA tumors.

Participant and Design We report the case of a 52-year-old woman with headache, tinnitus, and unilateral hearing impairment whose preoperative magnetic resonance imaging revealed a heterogeneously enhancing CPA mass that extended into the internal auditory canal.

Main Outcome Measures, Results, and Conclusion The preoperative imaging appearance of the lesion was most consistent with that of a schwannoma. Postoperative histopathologic examination found the tumor to be a CPP with cuboidal epithelial cells overlying fibrovascular stroma. CPPs are rare benign central nervous system neoplasms arising from choroid plexus epithelium. The most common site of presentation is in the fourth ventricle in adults and the lateral ventricles in children. CPPs rarely occur in the CPA, and when they do, clinical-radiologic diagnosis is difficult due to both the rarity of this presentation and to nonspecific radiological features.

Perfusion imaging in brain disease

Perfusion CT or MRI have been extensively developed over the last years and are accessible on most imaging machines. Perfusion CT has taken a major place in the assessment of a stroke. Its role has to be specified for the diagnosis and treatment of the vasospasm, complicating a subarachnoid hemorrhage. Perfusion MRI should be included in the assessment of any brain tumor, both at the time of the diagnosis as well as in the post-treatment monitoring. It is included in the multimodal approach required for the optimum treatment of this disease. The applications in epilepsy and the neurodegenerative diseases are in the evaluation process.

Classification methods for the differentiation of atypical meningiomas using diffusion and perfusion techniques at 3-T MRI

The purpose was to investigate the contribution of machine learning algorithms using diffusion and perfusion techniques in the differentiation of atypical meningiomas from glioblastomas and metastases. Apparent diffusion coefficient, fractional anisotropy, and relative cerebral blood volume were measured in different tumor regions. Naive Bayes, k-Nearest Neighbor, and Support Vector Machine classifiers were used in the classification procedure. The application of classification methods adds incremental differential diagnostic value. Differentiation is mainly achieved using diffusion metrics, while perfusion measurements may provide significant information for the peritumoral regions.

Sporadic intracranial haemangioblastomas: surgical outcome in a single institution series

BACKGROUND

Haemangioblastomas are benign vascular tumours that may appear sporadically or in von Hippel-Lindau disease. Despite their higher incidence, sporadic haemangioblastomas have been less studied than syndromic ones. In this article, we evaluate the specific features, outcome and quality of life of patients with intracranial sporadic haemangioblastomas (ISHs) operated on in our institution.

METHODS

Between 1998 and 2010, 38 patients harbouring 38 ISHs were operated on in our department. Their clinical, biological, radiological and surgical features were retrospectively reviewed. All patients were contacted for a quality-of-life (QOL) survey assessed by the Short Form 36 questionnaire (SF36). The mean duration of follow-up was 40 months (13-108 months).

RESULTS

ISH represented 0.9 % of primary intracranial neoplasms treated in our centre during this period. Patients comprised 23 men and 15 women with a mean age of 47 years. None had polycythaemia. Cerebellar locations accounted for 79 % of ISHs, and brainstem ISH with involvement of the floor of the fourth ventricle represented 11 % of ISHs. At last follow-up, two patients harbouring solid medulla oblongata haemangioblastoma had died following severe bulbar syndrome and five patients had died of unrelated causes. One patient had multiple surgeries for three recurrences. Tumoral control was achieved in all cases at last follow-up. Results of the SF-36 questionnaire were as follows: median physical functioning score 100 (range 0-100), median physical problems score 100 (range 0-100), median bodily pain score 100 (range 45-100), median social functioning score 100 (range 25-100), median general mental health score 84 (range 40-92), median emotional problems score 100 (range 0-100), median vitality score 70 (range 35-80) and median general health perceptions score 70 (range 35-100). Mean QOL scores were similar to the general healthy population.

CONCLUSION

Surgery of ISH provides good QOL and tumoral control except for those located in the medulla oblongata. We recommend considering a careful multimodal therapeutic approach, including radiosurgery for these specific locations.

Usefulness of perfusion weighted magnetic resonance imaging with signal-intensity curves analysis in the differential diagnosis of sellar and parasellar tumors: preliminary report

PURPOSE

The most common pituitary tumors are adenomas, which however may be mimicked by other tumors that can show a very similar appearance in plain MRI. The aim of our study was to evaluate the usefulness of perfusion weighted MR imaging (PWI), including signal-intensity curves analysis in the differential diagnosis of sellar/parasellar tumors.

METHODS

Forty-one patients with sellar/parasellar tumors (23 macroadenomas, 10 meningiomas, 5 craniopharyngiomas, 1 intrasellar hemangioblastoma, 1 intrasellar prostate cancer metastasis, 1 suprasellar glioma), underwent plain MRI followed by PWI using a 1.5T unit. In each tumor, the mean and maximum values of relative cerebral blood volume (rCBV), as well as the relative peak height (rPH) and the relative percentage of signal intensity recovery (rPSR) were calculated.

RESULTS

The high perfusion tumors were: macroadenomas, meningiomas, squamous-papillary type of craniopharyngiomas, hemangioblastoma, glioma and metastasis. The low perfusion neoplasms included adamantinomatous type of craniopharyngiomas. By comparing adenomas and meningiomas, we found statistically significant differences in the mean and maximum rCBV values (p=0.026 and p=0.019, respectively), but not in rPH and rPSR. The maximum rCBV values >7.14 and the mean rCBV values >5.74 with the typical perfusion curve were very suggestive of the diagnosis of meningioma. There were differences between adenomas and other high perfusion tumors in rPH and rPSR values.

CONCLUSIONS

PWI can provide additional information helpful in differential diagnosis of sellar/parasellar tumors. In our opinion PWI, as an easy to perform and fast technique should be incorporated into the MR protocol of all intracranial neoplasms including sellar/parasellar tumors.

Prospective evaluation of the clinical profile and referral pattern differences of vestibular schwannomas and other cerebellopontine angle tumors

OBJECTIVE

To evaluate the clinical profile, referral pattern, delay in diagnosis, and impact of tumor size of cases involving vestibular schwannomas (VS) versus other cerebellopontine angle (CPA) tumors in an Egyptian population.

STUDY DESIGN

Case series study.

SETTING

Tertiary referral center.

PATIENTS

A prospective study of possible retrocochlear lesions was conducted from 2008 to 2010.

INTERVENTION(S)

Patients were subjected to a full clinical history, complete otorhinolaryngological examination, a basic audiologic evaluation, auditory brainstem response assay, and gadolinium-enhanced magnetic resonance imaging. According to the findings of magnetic resonance imaging, patients with retrocochlear lesions were divided into 2 groups: those with VS (n = 17) and those with other CPA lesions (n = 14).

MAIN OUTCOME MEASURE(S)

Diagnostic delay and criteria of VS and CPA tumors.

RESULTS

Unilateral hearing loss and tinnitus were presented in 52.9% of VS cases with a diagnostic delay of 15.5 months. For cases involving other CPA lesions, a combination of otologic symptoms was observed in 9 (64%) of 14 cases, and a diagnostic delay of 47.5 months was experienced. An absence of auditory brainstem response waves was identified significantly (p < 0.05) for the affected ears of both groups. Only differences in Wave V latency were significant between the 2 groups (p < 0.05).

CONCLUSION

A longer diagnostic delay was associated with cases involving other types of CPA lesions versus cases of VS, and tumor size and volume did not affect the diagnostic delay of the former. Moreover, the only significant difference in clinical presentation for these 2 groups of intracranial tumor involved Wave V latency.

Quantitative Evaluation of Changes in the Selected White Matter Tracts Using Diffusion Tensor Imaging in Patients with Alzheimer's Disease and Mild Cognitive Impairment

This study evaluated the damage to the extensive range of white matter tracts in patients with Alzheimer's disease (AD) and mild cognitive impairment (MCI). Thirty-four patients with AD (mean age 71.5 yrs, MMSE 17.6), 23 patients with MCI (mean age 66 yrs, MMSE 27.4) and 15 normal controls (mean age 69 yrs, MMSE 29.8) were enrolled. Diffusion tensor imaging (DTI) was performed in 25 directions on 1.5 T MR scanner. Fractional anisotropy (FA) values were obtained with a small ROI method in several association tracts including posterior cingulum fibers, in commissural tracts (genu and splenium of corpus callosum) and projection tracts (middle cerebellar peduncles and posterior limbs of internal capsules). In MCI significant reductions of FA were found in the inferior longitudinal fascicles, left superior longitudinal fascicle and posterior cingulum fibers compared to normal controls. In AD significantly decreased FA values were detected in the same fascicles as in MCI and additionally in inferior fronto-occipital tracts and commissural tracts. In both AD and MCI the most severe changes were found within posterior cingulum fibers. No abnormalities were detected in projection tracts in both groups. Accuracy of DTI in detecting AD and MCI reached 0.95 and 0.79, respectively. FA measurements strongly correlated with neuropsychological tests. DTI is capable of depicting microstructural changes within white matter fiber tracts in dementia and may aid the differential diagnosis of AD and MCI.