Gadolinium-based contrast agents are category C drugs as determined by the FDA, with adverse effects in animal studies without adequate studies in humans, and their use in pregnancy is restricted to situations where the potential benefits of imaging far outweigh the potential risk to the fetus [98]. A study by Thomassin-Naggara et al [99] in 2017 demonstrated an overall accuracy of MRI in up to 88% in pregnant patients using the ADNEX MR score in a subset of 36 masses. In this study, 7 of 31 patients received gadolinium contrast based on radiologist discretion during the examination, with all 7 demonstrating malignant tumors on final pathology. MRI Pelvis Without IV Contrast Although MRI can accurately diagnose the presence of adnexal lesions and identify distinguishing characteristics such as the type of fluid content, presence of fat, or presence of septations in cystic lesions [16,17], it is not the first- line modality for initial evaluation. MRI does not use ionizing radiation and is deemed safe in pregnant patients [95]. Although contrast-enhanced MRI performs superiorly to both US and noncontrast MRI due to its ability to confirm the presence of internal enhancing soft tissue components [18], gadolinium-based contrast agents should not be routinely administered to pregnant patients [95]. Although not specifically assessed in the pregnant Clinically Suspected Adnexal Mass population, in a recent study of 350 lesions in a population with 15% malignant lesions, noncontrast MRI demonstrated a sensitivity of 85%, specificity of 96%, and accuracy of 94.2% to detect cancer [19]. If a pregnant patient with a suspected adnexal lesion is unable to be evaluated via US (due to large size of lesion >10 cm, poor acoustic window from adjacent viscera or body habitus, or unclear organ of origin), noncontrast MRI would be the best alternative imaging modality for evaluation.
Clinically Suspected Adnexal Mass No Acute Symptoms. Gadolinium-based contrast agents are category C drugs as determined by the FDA, with adverse effects in animal studies without adequate studies in humans, and their use in pregnancy is restricted to situations where the potential benefits of imaging far outweigh the potential risk to the fetus [98]. A study by Thomassin-Naggara et al [99] in 2017 demonstrated an overall accuracy of MRI in up to 88% in pregnant patients using the ADNEX MR score in a subset of 36 masses. In this study, 7 of 31 patients received gadolinium contrast based on radiologist discretion during the examination, with all 7 demonstrating malignant tumors on final pathology. MRI Pelvis Without IV Contrast Although MRI can accurately diagnose the presence of adnexal lesions and identify distinguishing characteristics such as the type of fluid content, presence of fat, or presence of septations in cystic lesions [16,17], it is not the first- line modality for initial evaluation. MRI does not use ionizing radiation and is deemed safe in pregnant patients [95]. Although contrast-enhanced MRI performs superiorly to both US and noncontrast MRI due to its ability to confirm the presence of internal enhancing soft tissue components [18], gadolinium-based contrast agents should not be routinely administered to pregnant patients [95]. Although not specifically assessed in the pregnant Clinically Suspected Adnexal Mass population, in a recent study of 350 lesions in a population with 15% malignant lesions, noncontrast MRI demonstrated a sensitivity of 85%, specificity of 96%, and accuracy of 94.2% to detect cancer [19]. If a pregnant patient with a suspected adnexal lesion is unable to be evaluated via US (due to large size of lesion >10 cm, poor acoustic window from adjacent viscera or body habitus, or unclear organ of origin), noncontrast MRI would be the best alternative imaging modality for evaluation.