3'-Deoxy-3'-[F-18]fluorothymidine positron emission tomography in patients with recurrent glioblastoma multiforme: comparison with Gd-DTPA enhanced magnetic resonance imaging.

INTRODUCTION

The accumulation of 3'-deoxy-3'-[F-18]fluorothymidine (FLT) on positron emission tomography (PET) images in patients with glioblastoma multiforme was evaluated and correlated with gadopentetate dimeglumine (Gd-DTPA) enhancement in magnetic resonance images (MRIs).

METHODS

FLT studies in 10 patients with recurrent glioblastoma multiforme were retrospectively investigated. Dynamic emission data were acquired for 60 minutes immediately after injection of FLT. The standardized uptake value (SUV) for tumor and reference tissue (contralateral hemisphere and ipsilateral cerebellum) was calculated. The volumes of the metabolically active part of the tumor (V (PET)) and that of the Gd-DTPA enhancing part of the tumor (V (MR)) were calculated.

RESULTS

FLT uptake in tumors peaked before 5 minutes and sometimes as early as 0.5 minutes, and reached a constant level at approximately 10 minutes after injection. The reference tissue time-activity curves had an early peak and reached a constant low background level. All tumors had increased FLT uptake and showed Gd-DTPA enhancement. The SUV in tumor was significantly higher than that in the reference tissue (P<0.0001). A significant correlation between V (PET) and V (MR) was found (P<0.0001) although there was a difference in the areas of Gd-DTPA enhancement and FLT uptake.

CONCLUSION

These preliminary results indicate that FLT-PET may be useful for the detection of recurrent glioblastoma multiforme. Our data in a relatively small patient population do not support a clear-cut relationship between FLT accumulation and Gd-DTPA enhancement. Further pathologic correlation will determine if it can be used for detecting recurrent tumoral disease.