 Hello everyone. My paper presentation topic is various presentation of meningioma under the guidance of Yogendra Sajdev, Sir, Professor and Head of Department of Radio Diagnosis, Pravaradu Hospital, Loni. I, Dr. Gheera Janeshgiri present this paper. Meningiomas are the most common non-glial tumor of the CNS, central nervous system. There are a number of characteristics imaging features of meningiomas on magnetic resonance imaging that is on MRI that allow an accurate diagnosis. However, there are a number of atypical features that may be diagnostically challenging. Furthermore, a number of other non-neoplastic and neoplastic conditions that may mimic meningiomas. This pictorial review discusses the typical and atypical features of meningiomas on MRI and their mimics. Meningiomas are the most common non-glial tumors of the central nervous system, accounting for between the 16 to 20 percent of intracranial tumors. Magnetic resonance imaging is the modality of choice for the investigation of meningiomas, providing superior contrast differentiation and usually the ability of differentiation between intracranial regions. In addition to MRI, computer tomography that is CT has a useful role in a specific cases where there is a calcification and adjacent changes to the calvarium. Although atypical meningiomas have characteristics imaging features, there are multiple atypical variants that may be diagnostically challenging and the value of MRI is predicting WHO grades in meningiomas is limited. A number of benign and malignant pathologies may also mimic some of the features of meningioma. It is important for the radiologists to have an understanding of the typical and atypical features of meningioma to aid their recognition and suggestion of a correct diagnosis. The typical and atypical imaging features of meningioma is this. Meningiomas may be found along any of the external surfaces of the brain as well as within the ventricular system where they arise from the stromal arachnoid cells of the coroid plexus. The most common location include a parasurgical aspect of the cerebral convexity, the lateral hemisphere convexity, the spinoid wing, middle cranial fossa and the olfactory groove. Meningiomas at the skull base may extend through foramina for example into the orbit and along the course of the trigeminal nerve. Meningioma represent the second most common mass lesion of the cerebellopontine angle secondary to the acoustic shamanoma. Less common location include the optic nerve sheath 0.4 to 1.3 percent of cases the coroid plexus 0.5 to 3 percent of cases most commonly in the trigon of the lateral ventricle in adults and the cellular tersica. Approximately 10 percent of the meningiomas arise in the spine very rarely representing approximately 1 percent of cases they may arise entirely outside the dura and may be purely extracalvaryl, calvaryl and calvaryl with extracalvaryl extension with sites including the temporal bone, mandible, mediastinum and the lung describe. The etiology of this ectopic location is thought to be due to a meningocytes or arachnoid capsules trapped in the cranial sutures during remoulding of the brain at birth as a result of trauma or as a result of meningoepithelial differentiation from multi-potential mesenchymal cell precursors. Ends an objective to evaluate the patients for the presence of meningioma in a patients refers to the department of radio diagnosis with the neurological symptoms inclusion criteria, patients giving consent for study, patients refers to radiology department with symptoms of headache, anosmia, gidiness, difficulty in vision and blurring of vision. Extrusion criteria, patients not giving consent for study, patients with contraindication for MRI such as claustrophobia, metallic implants, aneurysm, cleave, pacemakers, prosthetic hurt balls. Materials and methods cross-sectional study was performed, 12 patients were studied, assessment of the patients were done by using a three tesla philips ingenia illusion, imaging features of meningioma. meningioma typically appear as a lobular x-raxial mass with well differentiated margins. They typically have a broad base dural attachment and if sufficiently large cause a inward displacement of cortical gray matter. They may occasionally however exhibit a more infiltrating growth pattern over the dura commonly occur along the spinoid ridge or the convexity. The typical MRI signal intensity characteristics consist of iso intensity to slight hypo intensity relative to gray-white matter on the T1 weighted sequence and iso intensity to slight hyper intensity relative to gray-white matter on two sequence. After contrast administration, meningiomas typically demonstrate avid homogenous enhancement however they may occasionally have areas of central necrosis or calcification that do not enhance. Calcification is typically best demonstrated on CT with variable reported rates of occurrence on MRI. Calcification is best identified on susceptibility weighted images as areas of low signal intensity. However calcification may also be appreciated on T2 weighted sequences as areas of low signal intensity. Contrast is especially useful in delineating n-plug meningiomas that are typically seen as asymmetric thickened sheets of enhancing dura. Various locations of meningiomas. Most common location is a supra-tentorial. 85 to 90 percent occurs in a supra-tentorial region. Parasazetil convexity is 45 percent. The symptoms is caesars and hemiparesis, spinoid reach 15 to 20 percent. All-factory grew or platinum-spinoidal 10 percent. The symptoms is anasminia, usually not recognized. Foster-canady syndrome. Next is juxtasilar, 5 to 10 percent. In these, visual field defects or cranial now deficits are seen. Second most common is infratentorial. It occurs in 5 to 10 percent of cases. Obstructive, it causes obstructive hydrocopilus or cranial now deficits. Third is miscellaneous that is intradural less than 5 percent. Intraventricular meningioma or uptake now meningioma. Various signs in meningioma. CSF cleft sign which is not specific for meningioma but helps to establish the mass to be extra axial. Loss of these can be seen in a grade 2 and grade 3 which may suggest brain panchamic invasion. Second is dural tail sign is seen in 60 to 72 percent. Not that the dural tail is also seen in other processes. Sunbursts or scope will sign appearance of the vessels. White matter buckling sign, arterial narrowing, typically seen in meningioma which encases the arteries. Useful sign in paracellular tumors in distinguishing a meningioma from a pitidary macrodinoma. The lateral typically does not narrow vessels. Now we see the images. This is a spoke wheel sign then the cleft sign dural sign then white matter buckling sign MR spectroscopy. The findings in MR spectroscopy meningioma cases increase in alanine increase glutamine glutamate increase cooling absent or significantly reduce in acetyl aspirated non-neural origin absent or significantly reduce creatinine. In certain circumstances the presence of a dural tail may be useful to distinguish meningiomas from other potential etiologies. For example, in distinguishing meningioma from shanoma in the cerebellum pontine angle as the letter is not typically associated with the dural tail. Although common with meningioma the dural tail sign is not specific as it is also described in some metastases glial tumors and lymphoma. Another important imaging feature suggestive of an extra axial location is the presence of a CSF cleft between the tumor and the underlying brain cortex. The cleft may contain CSF or the cortical basal entrapped between the tumor and the underlying cortex. Bone changes associated with the meningiomas. Bone changes associated with the meningiomas include osteolysis or hypostasis with the later most common described in 20 percent of cases and most common with the plaque form. There may also be an enlargement of the skull base for a menon. The bone changes associated with the meningiomas are the base depicted and assessed on CT however they may be appreciated on MRI. Hypostasis is most common in tumors arising from the skull base and anterior canal fossa and the degree of hypostasis is not proportional to the tumor size. The pathological causes described include a direct tumor invasion of the bone and reactive hyper muscularity of the periosteum leading to benign bone formation. It made difficult to distinguish radiologically between the hypostasis associated with an n-plac meningioma and primary introsius meningiomas that is osteoblastic reported in 59 percent of cases particularly given that the later may be associated with underlying behavioral enhancement. Homogeneous dense enhancement of the tumor within the skull may help distinguish a primary introsius meningioma from a meningioma n-plac. Meningiomas located at the skull base by virtue of their position have the potential to contact and entice vessels particularly the carotid arteries. Supracellar meningioma with involvement of clenoid portion of ICL. Left enterium meningioma, seen in this. Then meningioma in cleft hyperatel region. Rightcipiangle meningioma, meningioma extends to the to involves fifth, sixth, seventh, eighth, ninth cranial nerves on right side it involves right vertebral artery and basilar artery. In these images of MRI we see rightcipiangle meningioma. Now on conclusion meningiomas are the commonest extra axial tumor of the CNS that can have a varied appearance on imaging. There are a number of typical and are typical MRI features of meningiomas that are described and it is important for the reporting radiologist to have a broad understanding of their variable potential appearance in order to differentiate the legions from the numerous legions that can mimic their appearance. Bibliography. Thank you.