Is magnetic resonance imaging a useful aid in confirming the diagnosis of nonmetastatic gestational trophoblastic neoplasia?

Magnetic Resonance Imaging (MRI) of the pelvis was performed in 25 patients with rising or persistently elevated levels of human chorionic gonadotrophin (hCG) after hydatidiform mole evacuation to determine whether this type of imaging would help confirm a diagnosis of neoplasia based on hCG measurement alone. All patients had low risk disease. The images were assessed for the presence of a myometrial mass, increased uterine vascularity, increased myometrial signal and the integrity of the junctional zone. A myometrial mass was present significantly more frequently in patients with high hCG compared to those with low hCG ( P = 0.017). The junctional zone also was disrupted more frequently in patients with an hCG greater then 1500 mIU/ml although this finding is not specific for trophoblastic neoplasia. There was no correlation of the presence of vascularity or of increased myometrial signal with the level of hCG. Patients with an hCG of less than 700 mIU/ml showed only occasional MRI abnormality. One patient with an abnormal MRI during an hCG plateau achieved spontaneous regression. MRI frequently shows abnormalities of uterine architecture, but provides no superior clinical information than sequential hCG. The MRI appearance may be abnormal with spontaneous hCG remission while at persistent low levels of hCG when chemotherapy is clearly indicated the MRI appearances of the uterus show no abnormality.