Assessment of Aggressiveness of Breast Cancer Using Simultaneous 18F-FDG-PET and DCE-MRI

Abstract

Purpose To investigate the feasibility of using simultaneous breast MRI and PET to assess the synergy of MR pharmacokinetic and fluorine-18 fluorodeoxyglucose (18F-FDG) uptake data to characterize tumor aggressiveness in terms of metastatic burden and Ki67 status. Methods Twelve consecutive patients underwent breast and whole body PET/MRI. During the MR scan, PET events were simultaneously accumulated. MR contrast kinetic model parametric maps were computed using the extended Tofts model, including the volume transfer constant between blood plasma and the interstitial space (Ktrans), the transfer constant from the interstitial space to the blood plasma (kep), and the plasmatic volume fraction (Vp). Results Patients with systemic metastases had a significantly lower kep compared to those with local disease (0.45 vs 0.99 min−1, p=0.011). Metastatic burden correlated positively with Ktrans and standardized uptake value (SUV), and negatively with kep. Ki67 positive tumors had a significantly greater Ktrans compared to Ki67 negative tumors (0.29 vs 0.45 min−1, p=0.03). A negative correlation was found between metabolic tumor volume and transfer constant (Ktrans or Kep). Conclusion These preliminary results suggest that MR pharmacokinetic parameters and FDG-PET may aid in the assessment of tumor aggressiveness and metastatic potential. Future studies are warranted with a larger cohort to further assess the role of pharmacokinetic modeling in simultaneous PET/MRI imaging.

PET/MRI in Breast Cancer

“…In that study, K trans and SUV max correlated positively with metastatic disease, whereas K ep correlated negatively. Similarly, tumors with higher levels of Ki67, a marker for cell proliferation, showed a significantly greater K trans compared with tumors with lower levels of Ki67 . Data like these suggest the potential for K trans and SUV max to suggest patients in whom whole‐body imaging should be performed to assess for metastatic disease.…”

“…Margolis et al evaluated perfusion data K trans , K ep , and V e , and 18 F‐FDG PET data standardized uptake value (SUV) and metabolic tumor volume (MTV) in breast cancer patients with and without metastases . In that study, K trans and SUV max correlated positively with metastatic disease, whereas K ep correlated negatively.…”

“…Catalano et al investigated whether 18 F‐FDG PET/MR could differentiate between histological phenotypes of breast cancer in 21 patients with invasive ductal carcinoma (IDC) . The authors found that estrogen receptor (ER) and progesterone receptor (PR)‐negative tumors had higher SUV max and K ep than ER or PR‐positive tumors; that HER2‐negative tumors had higher apparent diffusion coefficient (ADC) mean , K ep , and SUV max values; and that tumors with lower levels of Ki67 showed lower ADC mean , but not greater K trans , as seen in the Margolis et al study . PET/MR markers correlated with immunohistochemical (IHC) phenotype in 62%, a promising beginning …”

Voxelwise analysis of simultaneously acquired and spatially correlated 18F‐fluorodeoxyglucose (FDG)‐PET and intravoxel incoherent motion metrics in breast cancer

“…Chemotherapy regimens varied accordingly with the heterogeneity in histology and prognostic factors of the tumor and included hormone therapy and cytotoxic treatment. Results from the whole body PET/MR evaluation (33) or local DCE-MRI (34) of these patients have been recently reported and in some cases provided the metastatic burden assessment considered in the present study.…”

Breast PET/MR Imaging

“…This group also looked at recurrence-free survival and found that patients with more heterogeneous FDG uptake had worse recurrence-free survival than patients with less heterogeneous tumors. 45 In a smaller study, Margolis and colleagues 47 found that metabolic tumor volume inversely correlated with Kep and K trans and that metastatic burden correlated positively with K trans and SUVmax and negatively with Kep.…”