Correlation between 18FDG PET SUV with Partial Volume Correction and MRS Choline signal integral in breast cancer

Aim: Diagnostic tools in breast cancer (BC) diagnosis have, in general, evolved independently and reached maturity. The purpose of this study is to assess the diagnostic confidence of an integrated approach to BC patient management, by the combined use of: a) the quantification of glucose uptake as measured by 18FDG PET and b) the quantization of the choline levels as measured by Magnetic Resonance Spectroscopy (MRS). Methods: 17 women with biopsy proven BC have been enrolled in the study. All patients were examined with 18FDG PET-CT and 1H MRS before surgical resection of breast lesion. Averaged body-weight SUV with Partial Volume Correction (PVC) was calculated using a Recovery Coefficient-based method [Gallivanone et al, IEEE Trans Nucl Sci 2011, vol.58(3):736-47]. Absolute choline concentration has been quantified using water as internal reference and integral of choline signal (Cho) has been calculated with the AMARES algorithm [Vanhamme et al, J of Magn Res 1997, vol.129:35-43]. Correlation between SUV and Cho was evaluated using Pearson's correlation coefficient. Results: Invasive Ductal Carcinoma (IDC) was found in 14 patients and Invasive Lobular Carcinoma (ILC) in 3 patients. All IDC patients were choline positive at MRS (Cho > 0.002) and at PET (SUV> 3.32g/cc, average SUV = 8.58 g/cc), except one who was choline negative at MRS (cholin signal not present) but positive at PET (SUV = 8.6 g/cc). All ILC patients were choline negative at MRS and at PET and, except one who was positive at PET (SUV =3.22g/cc) but choline negative at MRS. SUV and Cho values were found correlated in both IDC (rho=0.57, p=0.031) and ILC patients (rho~1, p<0.001). Conclusion: The presence of the choline signal and/or an SUV > 3.32g/cc was found discriminating IDC from ILC. Although obtained from a limited number of patients, an integrated approach based on PET 18FDG SUV (with PVC) and MRS Cho was found enhancing the diagnostic confidence of BC.