As such, MRI has the potential to provide important information for treatment planning. Local parametrial invasion, vaginal involvement, and pelvic extension are all better assessed with MRI than US [44]. Because the primary tumor and GTN metastases are typically vascular, IV contrast enhancement is useful to improve lesion detection. Vaginal gel may be useful to distend the vagina, optimizing the delineation of any masses or extension, if present. The majority of patients with postmolar GTN not treated with hysterectomy will have locally invasive disease [17]. Given the rare nature of ETT and PSTT, there are few consistent descriptions of imaging features, limited to small series and case reports [15,52,65]. MRI assessment of lymph node status is important to treatment planning in patients with PSTT and ETT, but other forms of GTN predominantly spread via hematogenous routes. FDG-PET/CT Skull Base to Mid-Thigh The role of FDG-PET/CT in the evaluation of patients with GTN is inconclusive and evolving given the uncommon nature of the disease. There is some evidence that FDG-PET/CT may be useful to precisely map tumor extent prior to chemotherapy, as well as to monitor tumor response and identify sites of persistent disease following therapy [66-69]. One systematic review included 19 papers totaling 81 cases of GTN, with FDG- PET/CT used in the initial staging in 59 of 81 patients and in the follow-up after initial chemotherapy in 22 of 81 patients [47]. The largest study included in this review (41 patients) showed concordance between FDG-PET or PET/CT and conventional studies that ranged from 81% to 91% with the highest discordance in chest CT, all false-negative [68].
Gestational Trophoblastic Disease. As such, MRI has the potential to provide important information for treatment planning. Local parametrial invasion, vaginal involvement, and pelvic extension are all better assessed with MRI than US [44]. Because the primary tumor and GTN metastases are typically vascular, IV contrast enhancement is useful to improve lesion detection. Vaginal gel may be useful to distend the vagina, optimizing the delineation of any masses or extension, if present. The majority of patients with postmolar GTN not treated with hysterectomy will have locally invasive disease [17]. Given the rare nature of ETT and PSTT, there are few consistent descriptions of imaging features, limited to small series and case reports [15,52,65]. MRI assessment of lymph node status is important to treatment planning in patients with PSTT and ETT, but other forms of GTN predominantly spread via hematogenous routes. FDG-PET/CT Skull Base to Mid-Thigh The role of FDG-PET/CT in the evaluation of patients with GTN is inconclusive and evolving given the uncommon nature of the disease. There is some evidence that FDG-PET/CT may be useful to precisely map tumor extent prior to chemotherapy, as well as to monitor tumor response and identify sites of persistent disease following therapy [66-69]. One systematic review included 19 papers totaling 81 cases of GTN, with FDG- PET/CT used in the initial staging in 59 of 81 patients and in the follow-up after initial chemotherapy in 22 of 81 patients [47]. The largest study included in this review (41 patients) showed concordance between FDG-PET or PET/CT and conventional studies that ranged from 81% to 91% with the highest discordance in chest CT, all false-negative [68].