FLT PET/MR for Evaluation of Pseudoprogression in Patients With Brain Lesions

Identifying imaging biomarkers of metastatic brain tumor treatment response could allow early
modification of treatment by determination of tumor progression vs. treatment related effects
(pseudo-progression, radiation necrosis). Earlier treatment response assessment could reduce
cost, improve clinical trial efficiency and allow better assessment of prognosis. The
development of PET/MRI offers the possibility of combining the functional imaging of PET with
the exquisite soft tissue contrast and physiologic imaging capabilities of MRI. Combining
FLT-PET imaging with MRI may allow better evaluation of new and unclear lesions in brain
metastatic disease. The goal of this study is to explore FLT-PET imaging combined with
dynamic MR imaging techniques for the identification of tumor response markers in metastatic
brain tumors.

Inclusion Criteria:

- Known brain lesion in central nervous system (CNS) scheduled to have surgical biopsy
of the lesion, identified by the UNC Brain Tumor Board as having clinical question of
radiation necrosis vs. recurrence

- At least one measurable lesion greater than 1 cm in diameter

- ≥ 18 years of age

- Study-specific informed consent reviewed and signed

Exclusion Criteria:

- Pregnant, nursing, or planning to become pregnant within 30 days of anticipated
PET-MRI scan

- Condition that makes MRI unsafe (e.g., cardiac pacemaker, epicardial pacemaker leads,
cochlear implants, metal aneurysm clips, metal halo devices)

- Inability to tolerate MRI (e.g., unable to lie flat for > 1 hour, severe
claustrophobia)

- Allergy to MRI contrast agent (Magnevist, Multihance, Ablavar, Dotarem, Eovist,
Gadavist)

- Known allergy to fluorothymidine

- Study participation would cause significant delay (> 2 weeks) in scheduled standard of
care therapy

- Creatinine clearance < 60 ml/min, as estimated by the Cockcroft-Gault formula

- Body Mass Index (BMI) > 35

- Poorly controlled diabetes mellitus (fasting blood glucose > 200 mg/dl)