Mismatch between intratumoral blood perfusion and glucose metabolism in same patients with cancer by ¹⁸FDG PET/CT scans: A Pilot human study

Objectives ¹⁸FDG accumulated in less blood perfused hypoxic regions of tumors in ex vivo animal studies ( J Nucl Med 2010;51:632-8; J Nucl Med 2012; 53:1262-1268; Transl Oncol 2014;7:240-247). The study was to test the hypothesis that high glucose demand and blood perfusion were spatially exclusive in cancers of patients.

Methods Patients with pretreated cancer were fasted for 4-6h with serum glucose level less than 6 mmol/L were included in the study. The patient was first positioned on the bed of the Discovery ST¹⁶ PET/CT scanner, regional low dose CT scan was performed where tumors were included, dynamic PET (2sec per frame for 30 frames, then 30sec per frame for 10 frames and followed 1min per frame for 2 frames) was performed immediately after intravenous bolus injection of ¹⁸FDG (3.7MBq/kg). After approximately 60 minutes of ¹⁸FDG uptake, routine PET/CT was performed in the same patient. Tumor blood perfusion by early dynamic ¹⁸FDG PET was compared with tumor glucose demand by static PET 60 min after ¹⁸FDG injection.

Results Dynamic PET scans during 0-8min after ¹⁸FDG injection detected blood perfusion of tumors, static PET scans approximately 60 min after ¹⁸FDG injection visualized intratumoral glucose metabolism. In the cancer, regions with high ¹⁸FDG accumulation in 60 min-PET always associated with low blood perfusion (0-8min PET). On the other hand, high perfused regions had low ¹⁸FDG in the 60min-PET imaging.

Conclusions In cancer of patients, high glucose demand (¹⁸FDG accumulation) occurs in less perfused regions (likely hypoxia); well perfused tumor tissues may associate with low glucose demand. The combination of dynamic PET immediately after bolus injection of ¹⁸FDG with static PET 60 min later may provide both blood perfusion and glucose metabolism information for better cancer care.

Research Support Inner Mongolia Natural Science Foundation (China) awards (2012MS1153) Jiangsu Province Nuclear medicine Key Laboratory funding (KF201303)