Metabolic MRI may reveal tumor response to GIST drug in weeks, not months

This study tests whether a specialized MRI technique, called hyperpolarized 13C-MRI, can detect early metabolic changes in gastrointestinal stromal tumors (GIST) during treatment with imatinib. Standard scans like CT and MRI only measure tumor size, which can take months to change. By tracking how tumors process a labeled substance (pyruvate), the new method may show whether the drug is working much sooner. Thirty GIST patients starting imatinib will undergo this experimental scan along with standard imaging and blood tests, and their results will be analyzed to see if early metabolic signals predict eventual response.