The New Indian Journal of OBGYN. Epub Ahead of Print

Utility of magnetic resonance imaging in differentiating T1 fat saturated hyperintense lesions

Suhail Rafiq,Sheema Posh,Inayat Ellahi,Shabir Bhat

ABSTRACT

Background: Endometriosis is defined as non- neoplastic endometrial glands and stroma residing outside of the uterine cavity and myometrium. Magnetic resonance (MR) imaging has been shown to have higher specificity than ultrasonography (US) for diagnosis of endometriomas. “T2 shading” is the classic MR feature of an endometrioma and is defined as a cystic lesion with hyperintense signal on a T1-weighted image that demonstrates T2 shortening resulting in relative hypointensity on T2-weighted images. A new sign T2 dark spot defined as discrete, markedly hypointense foci within the cyst on T2weighted images with or without T2 shading was found to have higher specificity. Objectives: To assess sensitivity and specificity of T2 shading and T2 dark spot for diagnosing endometriomas. Methods: This was a prospective study done in collaboration by department of radiodiagnosis and imaging and department of gynecology and obstetrics from January 2019 to December 2019. 56 Females with T1 hyperintensity lesions on fat sat sequences on magnetic resonance imaging with pathologic diagnosis or follow up ultrasound revealing involution or significant decrease in size were assessed for finding sensitivity and specificity of T2 dark spot and T2 shading. Results: Multiplicity was found in 58% cases of endometriomas and only 4.1% of hemorrhagic cysts demonstrated multiplicity (p value<0.001). The sensitivity, specificity, positive and negative predictive values for T2 shading are 90.1%, 55.1%, 80.8% and 72.7% respectively. The sensitivity, specificity, positive and negative predictive values for T2 dark spot are 39.3%, 93.1%, 92.3% and 42.1% respectively. Conclusion: Both T2 shading and T2 dark spot increase the diagnostic confidence of radiologists in diagnosing endometriomas. T2 shading is sensitive while as T2 dark spot is more specific for endometriomas. Multiplicity of lesions is also in favor of endometriomas. This is particularly helpful to gynecologists in starting early treatment for endometriomas rather than waiting for pathological biopsies.