Imaging of gastrointestinal stromal tumors before and after imatinib mesylate therapy.

Gastrointestinal stromal tumors (GISTs) account for the majority of gastrointestinal mesenchymal tumors. Recent advances in treatment using the molecular targeting agent imatinib mesylate have shown startling response rates and variegated imaging findings. We present the various imaging appearances of GIST on computed tomography (CT) and magnetic resonance imaging (MRI), both before and after treatment.