 Hello, I am Dr. Rushali Thakkar, junior resident at Sir JJ Group of Hospitals and Grand Government Medical College, Mumbai. My topic is role of MRI in characterization of ovarian lesions. Ovarian masses are frequently encountered in routine clinical practice, often detected incidentally or in symptomatic patients. When symptomatic, they can present with a range of non-specific symptoms that vary depending on the size of the lesion. Of these, the most common symptoms are abdominal or pelvic pain and abdominal distension. And the most commonly done serum marker is CA-125. Ultrason is often the first imaging modality performed because it is widely available, non-invasive and of low cost. However, MRI helps to confirm and provide additional information in characterization of lesions. Urats helps to determine the risk of malignancy, however, based on morphological appearance and tissue composition, further characterization is possible. Based on morphological appearance, adnexil masses can be divided into four main groups which is ureolocular cyst, multilocular cyst complex which contains both solid and cystic components and predominantly solid. The lesions can be further characterized by signal intensity features that is hemorrhagic areas, elevated protein content, fat, collagenous tissue and enhancement pattern. Now I have a few commonly encountered cases of which the first case is of a 48-year-old unmarried nulligravada with occasional pain in abdomen since 7 months. The images show a large abdominopelvic unilocular cystic lesion with enhancing volume. There is no fat content differential intensity within the cyst or solid component which favours serocystidinoma. Case 2 is a 27-year-old P2L2A1 patient with intermittent pain over left side of the lower abdomen since 3 months and which was aggravated since past 8 days. The images show bulky left ovary with two cysts showing fluid-fluid levels and appearing hyperintense on T1 which suggests presence of blood. Left ovary does not show post-contrast enhancement features therefore suggest endometriotic cyst with necrosis and chronic torsion of left ovary. Case 3 is a 65-year-old female with complaints of abdominal pain and tenderness since 1 month. Images show multi-loculated cystic left in exilesion with variable signal intensity in the locutes on both T2 and T1 weighted images giving typical stained glass appearance and which also suggests mucinous content within. Features favours mucinous cystidinoma, carcinoma. Case 4 is a 39-year-old female with irregular menses since 3 years. These show a well-defined thin wall lesion in the left ovary where peripheral aspect appears hyperintense on T1 and T2 weighted images and show fat suppression on T1 saturation sequence. Presence of fat intensity favours mature cystic teratoma. Case 5 is a 64-year-old post-menopausal female with abdominal pain, bloating and abdominal distention since 15 days. So one can see large solid cystic tumours arising from bilateral adnexam. The solid component shows diffusion restriction and post-contrast enhancement. Mild acitis with diffuse omental caking and nodular deposits were also present on abdominal screening and features favours cirrus cystidinocarcinoma. Case 6 is a 26-year-old unmarried nulligravada who came with gradually progressive pain in abdomen since 1 month which was aggravated during menses. Images show a large, multi-loculated solid cystic abdominal pelvic mass with stick component of various intensities, peripheral contrast enhancement and solid component showing diffusion restriction and heterogeneous post-contrast enhancement. Features favours musinocystidinocarcinoma. Case 7 is a 40-year-old female with pain and abdomen and fever on and off since 2 months. Patient was first diagnosed as PID with tubo ovarian abscess, however on further investigation abdominal cox was ruled out. So MRI was done which showed a solid cystic lesion with solid component showing diffusion restriction. There is also post-contrast enhancement of the cyst wall and the solid component. Similar lesion was also seen on the left side. Gross acitis omental caking, peritonal deposits and gross right-sided pleural effusion was also present. Features therefore favoured neoplastic etiology and patient was later diagnosed as seris cystidinocarcinoma. Case 8 is a 39-year-old female who had come with abdominal pain and abdominal wall abscess with ulcer and pus discharge from the ulcer side. The images show a solid cystic right-egg nexal lesion with cystic component showing central diffusion restriction and solid component having post-contrast enhancement without diffusion restriction. Features favoured infection. Now transsectal biopsy was later done which ruled out malignancy and patient which was eventually started on anti-tubricular regimen. Case 9 is a 60-year-old postmenopausal female with pain in abdomen and low-grade fever since two months. Images show a large abdominopelvic T2T1 weighted hypo intense solid lesion with patchy areas of diffusion restriction and contrast enhancement. Features favoured fibroma, ticoma, changes of diffuse adenomyases are also seen. Now ovarian masses can thus exhibit a diverse area of morphological characteristic. Some of the key imaging features that could be of help in differential diagnosis of ovarian masses are. So, we divided morphologically as ovarian lesions as cystic complex with both solid and cystic component and predominantly solid. Now when cystic it can be unilocular or multi-locular. In unilocular when they are less than 3 cm they are functional cyst more than 3 cm it can be a simple cyst and when they are extremely large diagnosis of cyst adenoma is considered. Presence of T1 hyper intensity within the cyst indicates a hemorrhagic or endometriotic cyst. When multi-locular it is a cyst adenoma. Now epithelial ovarian tumors are the most common of which cyst adenomas are the most common benign epithelial tumors which typically manifest as thin walled unilocular or multi-locular cyst. Now see the cyst adenoma typically are unilocular with thin walls often appearing bilaterally while musin-assisted adenomas tend to be larger and multi-locular featuring cystic locus with musin pendant and thus resembling a stained glass appearance. Distinguishing between a borderline and malignant cystic tumor is difficult however it relies on the presence of solid components irregular thick wall and septum. These features are more frequently observed in malignant tumors whereas borderline tumors typically lack secondary signs of malignancy such as acitis and omenial caking. Now when complex lesion has a solid component which shows heterogeneous enhancement and diffusion restriction it indicates epithelial cell tumors of which cyst adenoma and cyst adenocarcinoma are the most common. Now if the cystic component shows diffusion restriction it points towards abscess suggesting tubo ovarian abscess and due to high prevalence of tuberculosis in India tubo ovarian abscess needs to be considered and differentiated from malignancy as acitis and omenial caking are overlapping features. If the solid component shows fat intensity terratoma is to be considered. If it is a predominantly solid lesion with very low signal intensity on T2 weighted images it suggests presence of fibrotic component indicating ticoma, fibroma, cyst adenofibromas or brenant tumor. If the solid component shows fat intensity it is terratoma and if it is a complex enhancing mass which is present in both the ovaries and eventually if an unknown primary is identified it is metastasis. So while characterizing the lesion may not always be feasible necessitating histopathological conformation commonly encountered tumors often manifest distinctive features that aid in the diagnosis through MRI making it a valuable diagnostic tool for pre-operative evaluation of ovarian masses. Thank you.