Triple-phase contrast-enhanced MRI for the prediction of preoperative chemotherapeutic effect in patients with osteosarcoma: comparison with (99m)Tc-MIBI scintigraphy.

OBJECTIVE: This study aims to determine whether (99m)Tc-MIBI scintigraphy and triple-phase contrast-enhanced magnetic resonance imaging (TCE-MRI) performed during and after preoperative chemotherapy have the power to predict final chemotherapeutic effects in patients with osteosarcoma (OS).

MATERIALS AND METHODS: Seventeen patients underwent (99m)Tc-MIBI scintigraphy and TCE-MRI before and after the middle and last courses of preoperative chemotherapy. As for (99m)Tc-MIBI scintigraphy, an uptake ratio (UR) and a reduction rate of UR (ΔUR(MIBI)) were calculated. As for TCE-MRI, a ratio of contrast to background (CTB) was calculated in the whole tumor area (WA) at each phase on dynamic T1-weighted fat suppression images. Then a ratio of signal (R(WA)) was calculated by dividing CTB at triple-phase by CTB at pre-phase.

RESULTS: Nine and eight patients showed good and poor response in histopathologic evaluation. The sensitivity, specificity, and accuracy for the prediction of histopathological chemotherapeutic effect was 44, 100, 69% in R(WA) at the first phase, 100, 75, 88% in ΔUR(MIBI) after the middle course, 88, 100, 94% in R(WA) at the first phase, and 100, 75, 88% in ΔUR(MIBI) after the last course of the preoperative chemotherapy, respectively.

CONCLUSION: Both (99m)Tc-MIBI scintigrapy and TCE-MRI can predict the tumor response in patients with OS after the completion of the preoperative chemotherapy.