 Hello everyone. Myself Sanath, junior resident, department of radio diagnosis, Mysore Medical College and Research Institute Mysore. I would like to thank Indian radiologist for giving me this opportunity. The title of the topic is, role of MRI in evaluation of primary mob tumors in tertiary care center. Introduction. Tumor is an abnormal benign or malignant new growth of tissue that possesses no physiological function and arises from uncontrolled usually rapid cellular proliferation. Primary neoplasms of the skeleton are there, amounting for only 0.2% of overall human tumor burden. The evaluation of bone tumors often requires more than one imaging modality, including radiography, bone syndigraphy, CT, MRI and Pectin. Radiographs provide critical information regarding lesion location, margin, matrix mineralization, cortical involvement and adjacent periosteal reaction. Contrast enhanced MRI can reveal the most vascularized part of the tumor and MRI guidance makes it possible to avoid biopsying, necrotic areas. Diffusion weighted imaging shows restriction of diffusion of motor molecules in malignant tumors. MRI is very helpful in local staging and surgical planning on assessing the degree of intermedulary extension and invasion of the adjacent by cell plates, joints, muscle compartments and neuromuscular bundles. It can be used in assessing response to newer joint therapy and further pre-staging. The post therapeutic follow-up can also be done using MRI. Games and objecting to study the role of MRI in primary bone tumors to determine the MRI characteristic of different primary bone tumors. To evaluate the role of MRI in prediction of malignancy and delineation of anatomic extent of primary bone tumors, correlate and compare imaging findings with surgical and dystopathological findings wherever possible. Materials and methods. Study design is a descriptive type of study. The source of data or the patient who are suspected or diagnosed of having primary bone tumors, refer to Department of Rediagnosis, Meridio diagnosis, Care Hospital, Mysope. The sample size of the study was 40. The calculation is based on prevalence of primary bone tumor for which MRI was done is equal to 2.12% according to hospital records with level of significance of 5% and maximum allowable error as 5%. Inclusion criteria, patients with either clinically suspected or diagnosed of primary bone tumors on patients of all age groups were included. Exclusion criteria, patients with pacemakers, electromagnetic stents, patients with contraindication to contrast agents, patients having history of claustrophobia and diagnosed suspected cases of primary bone tumors which were diagnosed as metastatic or inflammatory or infective etiology on histopathological examination were excluded from the study. Recurrent cases as orthopedic implants adjacent to the tumor side scan was RTMS. Technique. Detailed history was recorded. All patients were first first evaluated with plane film examination followed by MRI. Few patients were subjected to CT scan. Patients fulfilling the inclusion and exclusion criteria underwent plane and contrast advanced MRI. MRI imaging was performed on a GE Optima MR360 1.5 Tesla MRI system. The following sequences were selected as required. Suzytel and Axial T1 weighted sequence. Suzytel and Axial T2 weighted sequence. Suzytel and Axial T2 sequence. Coronal proton density sequence. Post-contrast facts are T1 weighted images and Axial deposition weighted images. Results. In our study, 10 cases were in the age group of 10. Age group of below 10 years followed by 9 cases in 41 to 50 years. Primary bone tumors were more common in males than in females. In our study, most patients presented with pain and swelling. All the tumors which were incidentally found out were benign tumors which compressed between percent. In our study, most primary bone tumors were observed in the appendicular skeleton than in the axial skeleton. Tumor is the most commonly involved bone, followed by humerus, pylings, skull, vertebra which constitutes 10% in G. In our study of primary bone tumors, 37 cases were lytic lesions. Out of these, 22 cases were purely lytic. Six cases were lytic destructive. Nine cases were lytic sclerotic in nature. Only three cases were purely sclerotic. In our study, 25 cases had a well-defined margins. Of all were benign and 15 cases had ill-defined bottles of all were malignant except one which was a benign chain cell tumor. Margin characteristics and degree of malignancy of tumor showed significant association. Comparison of zone of transition of the bone tumor with benign and malignant characteristics. In our study, 25 cases had narrow zone of transition. Of all were benign and 15 cases had wide zone of transition. All were malignant except one which was a benign philus dysplasia. Zone of transition of lesion and degree of malignancy showed significant association. Comparison of radiography and MRI, evaluating soft tissue involvement. Tiesquare test and future exact test, strongly significant of p-value less than 0.01. In our study, 15 cases revealed soft tissue involvement on radiograph and MRI. In one case, soft tissue involvement was not identified on radiographs. While MRI revealed the soft tissue involvement and assisted the diagnosis and hence management of the patient, the lesion was a case of chain cell tumor. A significant association is obtained between soft tissue component and degree of malignancy in both MRI and radiograph. Distribution of cases showing bone marrow involvement on MRI imaging. MRI imaging determined bone marrow involvement in 36 cases. The cases which were not showing bone marrow involvement constitute 4 in number and all of them were benign except one which was periosteal osteosarcoma. Distribution of pathologies. In our study group of 40 cases, chain cell tumor was most common pathology observed in 8 cases, followed by condosarcoma and osteosarcoma comprising 6 cases each. Distribution depending upon benign and malignant characteristic. Based on imaging, in our study of 40 cases, 26 cases were benign and 14 cases were malignant lesions. Case 1, condosarcoma. Frontal radiograph of the sacrum showing ill-defined lytic lesion involving lower sacrum-frontal right side. CT bone marrow showing lytic lesion with soft tissue component and faint specks of calcification involving sacrum-frontal right side. Coronan T1, Axl T2, Axl Strip and Diffusion Weighted and Post Contest T1 Parasatimages showing an ill-defined lytic heterogeneously enhancing T1 Hypo intense T2 and still hyper intense lesion with soft tissue component showing diffusion restriction. Case of plasma cytoma, the frontal radiograph of left shoulder showing ill-defined lytic destructive lesion involving left scapula with thin specks of calcification within. Axl CT of left shoulder showing lytic destruction of left scapula with calcification and soft tissue component within. T1 coronal, proton density coronal, T2 coronal and post contrast T1 Axl images showing large, globalated, complex cystic mass lesion with heterogeneously enhancing solid component within. Involving scapula causing bone destruction, cystic component of lesion appears predominantly hyper intense on T1, T2 and proton acidivated images. Osteosarcoma, frontal radiograph and CT images on the right knee joint shows ill-defined radiopic lesion in metadipacyl region of lower end of femur with periosteal reaction forming corbin triangle. Sacrital T1, coronal T2 and coronal stubbing edges showing a low dilated mass involving lower metadipasis of femur appearing hyper intense on T1, hyper intense on T2 and still with break in the cortex and extruding soft tissue component on the middle aspect. Post contrast T1 paracetamase shows heterogeneous contrast enhancement and deputant distributed image shows deputant restriction. Case of Nconchroma, frontal radiograph of the right hand shows a well-defined expansional lytic lesion with internal tribulations and cortical break involving proximal phalanx of throat finger, coronal T1, coronal T2 and sternum edges showing a well defined altered signal intensity lesion within proximal portion of the proximal phalanx of the index finger appearing hyper intense on T1 and homogeneously hyper intense on T2 and sternum edges. Case of Giantside T1, frontal and lateral radiograph of the right knee showing well defined lytic lesion with internal tribulations involving epi metaphyseal region of lower end of femur, coronal CT image shows soft tissue component within. Sacrital T1, coronal T2 and coronal stubbing edges showing a fairly well defined, lobulated T1, hyper intense T2 and still heterogeneously hyper intense lesion, epi metaphyseal lesion of lower end of femur. Contrast coronal T1 images shows heterogeneous contrast enhancement. Case of Talar and usable bone cysts, oblique and frontal radiograph of foot and ankle. Foot with ankle shows expansion lytic lesion with internal septations within noted in talus. Coronal CT image shows cortical break, coronal T1, sagittal T2, sagittal sternum edges sequence show an expansion multiloculated lytic lesion with fluid fluid level within noted in talar bone. On post contrast, sagittal T1 fat satin edges shows no evidence of enhancing soft tissue component. Discussion. In our study, 40 cases of either suspected or diagnosed primary bone tumors were included. Age range of cases was 11 to 65 years with a mean age of 28 years and most patients were in the age group of below 20 years comprising 25% of cases. The result obtained was comparable with the previous prospective observational study conducted by Nulia Eidau in 2016. Lesions were more common in males than in females. Similar results showed in previous study conducted by Oberlamp DC Eidau in which 60% were males 39.4% were females giving a male to female ratio of 1.5 to 1. In our study group of 40 cases, 20 years cases with benign comprising 65% of and rest 14 cases were malignant. In a retrospective study by Oberlamp DC Eidau, 366 were benign while 342 were malignant which was comparable with our study. Gensel tumor was the most common pathology considering 8 cases followed by 6 cases of controsarcoma and osteosarcoma followed by incontroma comprising 5 cases. Comparable results were showed in a prospective observational study by Nulia Eidau which showed Gensel tumor of the bone was the most common histological diagnosis followed by Nulismal bone system. Conclusion and algorithmic approach that combines the radiographic and MR imaging characteristic with established demographic data helps to narrow down differential diagnosis of primary bone tumors. Conventional radiography is the first line of investigation for bone tumors. The radiographs can localize the lesion and determine the aggressiveness based on the margins zone of transition and soft tissue component. This helps the radiologist to make an informed differential diagnosis. MRI is prepared modality to image musculoskeletal system and should be obtained after a radiographic evaluation. Its multi-planar imaging capability helps to eliminate extent of tumor and invasion of the adjacent piscial blades, joints, muscle compartments, neurovascular bundles with high contrast resolution. These are my references. Thank you.