Tumor hypoxia and microscopic diffusion capacity in brain tumors: A comparison of 62Cu-Diacetyl-Bis (N4-Methylthiosemicarbazone) PET/CT and diffusion-weighted MR imaging

Objectives

The aim of this study was to clarify the relationship between tumor hypoxia and microscopic diffusion capacity in primary brain tumors using ⁶²Cu-Diacetyl-Bis (N4-Methylthiosemicarbazone) (⁶²Cu-ATSM) PET/CT and diffusion-weighted MR imaging (DWI).

Methods

This study was approved by the institutional human research committee and was HIPAA compliant, and informed consent was obtained from all patients. ⁶²Cu-ATSM PET/CT and DWI were performed in a total of 40 primary brain tumors of 34 patients with low grade glioma (LGG, n?=?13), glioblastoma (GBM, n?=?20), and primary central nervous system lymphoma (PCNSL, n?=?7). ⁶²Cu-ATSM PET/CT parameters and apparent diffusion coefficient (ADC) obtained by DWI were compared.

Results

High intensity signals by ⁶²Cu-ATSM PET/CT and DWI in patients with GBM and PCNSL, and low intensity signals in LGG patients were observed. An inverse correlation was found between maximum SUV (SUV_max) and minimum ADC (ADC_min) (r?=??0.583, p?ratio) and ADC_min for all tumors (r?=??0.532, p?max and T/B_ratio in GBM were higher than LGG (p?p?p?=?0.033 and p?=?0.044). The ADC_min was lower in GBM (p?=?0.011) and PCNSL (p?=?0.01) than in LGG, while no significant difference was found between GBM and PCNSL (p?=?0.90).

Conclusion

Tumor hypoxia assessed by ⁶²Cu-ATSM PET/CT correlated with microscopic diffusion capacity obtained by DWI in brain tumors. Both ⁶²Cu-ATSM PET/CT and DWI were considered feasible imaging methods for grading glioma. However, ⁶²Cu-ATSM PET/CT provided additional diagnostic information to differentiate between GBM and PCNSL.