 Good evening everyone, my paper title is characterization of cystic intracranial brain lesions using diffusion tensor imaging matrix. Background, cystic intracranial lesions are common findings in MR imaging, the differential diagnosis ranging from simple arachnoid cyst to high grade tumors is cystic component where the management grocery differs from cyst which requires no treatment to surgery. Intracranial cyst can be divided into non-neoplastic and neoplastic lesions. And this differentiation of intracranial cystic lesions is sometimes difficult by conventional MR imaging alone. So, such conventional scans are not sensitive to microstructural architecture of tissue. For DTI, it is an advanced MRI sequence based on diffusion weighted imaging that non-invasively displays the pathophageological changes of altered brain structures. In this, the brain tissue water can not move freely in all directions as surrounding tissue structures limit its movement and hence shows preferential movement along certain directions. Likewise, it is easier for water to diffuse along the course of a white matter fiber rather than perpendicular to it. As external membranes and myelin teeth act as a barrier to the movement of water molecules, this property of preferential movement is diffusion anisotropy. The DTI technique basically capture mean diffusivity and fracture anisotropy by placing the cursor on the ROI. Aims characterization of intracranial cystic lesions using diffusion tensor imaging matrix. Total sample size taken is 15. Now cases. First is epidermoid cyst. In this, an ill-defined irregular, lobulated extra axial cystic lesion is seen in the right cerebellum pontine angle, appearing hypointense on T1, hyperintense on T2 with partial separation on flare images, causing mass effect on bones and cerebral peduncle and showing diffusion restriction on the DWI and thin peripheral rim of enhancement on post-contrast scan. The FA value fraction anisotropy is highest that is 327. Now second is dermoid cyst. In this, a well-marginated extra axial fat containing midline lesion is seen in the anterior inter hemispheric fissure, appearing T1 heterogeneous signal with few hyperintense area, showing signal separation on fat set images and T2 hyperintense and diffusion restriction on DWI and no post-contrast enhancement is seen. In this also, FA is 157 and because of the heterogeneous content in the dermoid cyst. Now third is a recnoid cyst. In this, a well-defined extra axial, well-defined drown lesion seen in the retro cerebellum location posterior to the right cerebellar hemisphere, showing CSF attenuation on all sequences and no diffusion restriction is seen on DWI. Here ADC value is highest because there is no, because it is water CSF density. So moment of water molecules is easy. Now fourth is colloid cyst. In this, a well-defined drown lesion is seen at the foremen of Monroe, appearing iso-intense on T1, T2 and hyperintense on flare. Here FA value is around 150 due to the increased muscine content. So FA value is highest, is little less than the epidermoid cyst. Now fifth is racemos neurocystisarchosis. In this multiple well-defined inter-communicating cystic T1 hyperintense, T2 hyperintense lesion seen along the inter hemispheric fissure showing complete separation on flare images and few cells of A2 segment are seen traversing through the cystic space and no abnormal post-contas enhancement is seen. Sixth is vestibular swenoma. In this, a large, low-related extra axial mass of size 4 into 3 into 2 is noted in the left cerebellum-contine system with inter-canalicular extension of the left internal acoustic canal via porous equestricus. The lesion is hypo-intense on T1, heterogeneously hyperintense on T2 and few areas suppressed on flare, suggestive of cystic changes. Few areas in the mass appears bright on DWI and dark on ADC, suggestive of restriction. Blooming foci are also seen in the mass. Now seventh is pyrocystic astrocytoma. It is a heterogeneously enhancing T2 hyperintense lesion seen in the anterior para-felsine right frontal region with mild perifocal edema. On post-contrast, lesions shows non-enhancing cystic necrotic area and enhancing solid component. ADC value is higher in this because of the CSF nature. Now corollate plexus cyst in this a multi-lubulated cystic lesion noted within the body of lateral ventricle causing moderate dilatation and irregular ependymal lining of lateral ventricles. The lesion shows CSF signal on own sequences. Corollate plexus not visualized separately within the lateral ventricle and mark thinning of the corpus callosum is seen. The next is abscess. An area of altered signal intensity is noted in the left medial temporal lobe adjacent to the left cavernous sinus appearing hypo-toisone T2 flare with smooth peripheral post-contrast enhancement. And in abscess, ADC value is low. Tuberculoma, there are few irregular variable size conglomerated peripherally enhancing lesion seen largest of size 16 to 19 seen in the right cerebellar hemisphere, appearing T1, T2, hypo intense with surrounding peri-lesional edema. No diffusion restriction is seen on the DWI. Centrelurocytoma, a well-defined cystic lesion located in the body of right lateral ventricle, causing its expansion and sifting the septum pallicidum to the left. On SWI images, it shows blooming with hyper intense signal on face as to hemorrhage. The solid areas of lesion source diffusion restriction on post-contrast and the lesion source nodular enhancement with enhancing septa with non-enhancing necrotic area within. Next is cystic pituitary macrodinoma. It is a well-marginated lesion cellar mass with supra-cellar extent, not supra-cellar. It is a well-marginated lesion seen in the cellar and appearing homogenously hyper intense on T2 flare with known visualization of anterior pituitary separately. And the lesion enhances peripherally on post-contrast scan. Now, anaplastic oligodendroglioma. It is a well-delinated peripherally cortical-based interaxial mass that is seen in right parieto temporal region involving cortex and subcortical white matter. It appears hyper intense on T1, hyper intense on T2, iso-hyper intense on flare with few areas of blooming on SWI as to hemorrhage. It shows patchy areas of restriction and shows post-contrast heterogeneous enhancement with non-enhancing area as to necrosis. Now, craniopharyngeoma. It is a multilobulated solid cystic mass noted predominantly in the supra-cellar region. And it is the cystic component of the mass is hyper intense on T1 and T2 and not completely suppressed on flare. Solid component of the mass is iso intense on T1 and hypo intense on T2. Blooming foci are seen peripherally around the lesion on SWI. Solstice of calcification, no evidence of diffusion restriction is seen and on post-contrast scan the mass is showing peripheral enhancement and MRSO's large leptate peak. Hemangioblastoma. It is a well-defined predominantly cystic lesion with enhancing neural nodule seen in the right cerebellar hemisphere with mass effect as described. Now, results are the studies revealed that fractional isotope and mean diffusivity values helps in differentiating various cystic brain lesions. And epidermoid cysts found to have increased FA value but ADC values similar to that of the normal white matter. So, basically, FA is increased because of the creatinine content which leads to compact internal architecture. Neurosystic sarcosis showed high FA next to epidermoid cyst and DTI helpful in characterizing various stages of NCC. Brain abscess showed decreased ADC values while cystic tumor showed increased ADC and low FA values. Brain abscess showed decreased diffusion due to the inflammatory cells and debris within. While tumor cyst showed increased diffusivity due to clear fluid and less inflammatory cells. Arachnoid cyst, coratlexus cyst showed high ADC values and low FA value because of the CSF nature and less hindrance to the water molecules. Low-grade tumor cyst showed decreased FA and high ADC values and high-grade tumor cyst showed increased FA and decreased ADC due to more cellular component. Tuberkloma showed decreased ADC values and dermoid cyst and colloid cyst showed increased FA. The ADC values were found to be higher than that of the normal brain parenchyma but less than that of the CSF. The viscous nature of the content inside the colloid cyst leads to increased diffusion. Hence, diffusion tensor imaging derived matrix helpful in distinguishing cystic brain lesions. Conclusion. DTI with calculated FA MD values that is ADC values add more information to the MRI in differentiation of cystic brain lesions and help in therapeutic decision making and eventually patient outcome. Thank you.