role of MAGNETIC RESONANCE spectroscopy and diffusion weighted imaging in EVALUATION OF OVARIAN TUMORS

Abstract

varian cancer is the most lethal gynecological malignancy and the fifth leading cause of cancer-related deaths in women. Final diagnosis of ovarian tumors is based on histological examination, however it is important preoperatively to differentiate benign from malignant lesions, to avoid unnecessary operations, and to decide the appropriate type of surgery. Ultrasound is the primary imaging modality for the characterization of adnexal lesions; however the high soft tissue contrast resolution of MRI helps in the characterization of indeterminate adnexal lesions. Functional imaging is becoming increasingly important in the evaluation of cancer patients because of the limitations of morphologic imaging. Diffusion weighted magnetic resonance imaging (DW-MRI) is sensitive to molecular diffusion which is due to random microscopic translational motion of water molecules (known as Brownian motion). And thus contributes to differentiation between benign and malignant masses, especially when used in correlation with conventional MRI findings as previously described, with sensitivity 93% and specificity 89%. DWI also plays additional role in the detection of tumor recurrence, nodal affection and detection of metastasis. Apparent diffusion coefficients (ADC mapping) derived from DWI provides a quantitative parameter of the diffusivity of the imaged tissue. MRS is a noninvasive diagnostic tool for the investigation of tumor metabolism and is a meaningful supplement to conventional MRI. In the application of ovarian tumors, 1H-MRS is still in the preliminary stage, However in vivo 1H-MRS can quantitatively evaluate the metabolite concentration in ovarian tumors , which is helpful in differentiating benign from malignant ones ,thereby provide assistance in surgical planning In conclusion, The combination of DWI and Magnetic resonance spectroscopy to conventional MRI for discrimination between benign and malignant ovarian neoplasms, may improve the specificity of MRI and thus increases the radiologists confidence in image interpretation and provides a reliable predictive tool for the surgical outcome in ovarian neoplasms.