title: Follow-up of gastro-intestinal stromal tumours (GIST) during treatment with imatinib mesylate by abdominal MRI.
abstract: Typical MRI findings for gastro-intestinal stromal tumours (GIST) under treatment with imatinib were evaluated. MRI was performed in 45 patients (25 responders, 20 non-responders) with metastatic or locally advanced, unresectable GIST. Target lesions were selected and re-evaluated after 2, 4, and 6 months of therapy with imatinib. The target tumour response (TTR) was classified according to RECIST criteria. TTR, signal intensity in the centre and border of the lesion and the presence and the extension of a hypervascular rim were analysed. The mean diameter of the marker lesions decreased significantly (P<0.001) from 7.1+/-2.6 cm to 5.9+/-2.3 cm after 6 months. Accuracy of RECIST criteria was 51%, 69% and 73% on MRI 2, 4 and 6 months for response assessment. In addition, responders had higher signal-to-noise ratios on T2-w images after 2 months (P<0.05) and a decrease of vascularised areas in the lesion 4 and 6 months after treatment (each P<0.01), when compared with non-responders. Beyond the size measurement for response assessment, MRI provides additional information of tumour response using SI of T2-w images and quantification of vascularised areas of GIST manifestations.
authors.affiliation: Klinik und Poliklinik für Strahlenheilkunde, Campus Virchow Klinikum, Charité Universitätsmedizin Berlin, Augustenburger Platz 1, 13353, Berlin, Germany. stros@charite.de
authors.forename: Christian
authors.initials: C
authors.lastname: Stroszczynski
authors.forename: Dominik
authors.initials: D
authors.lastname: Jost
authors.forename: Peter
authors.initials: P
authors.lastname: Reichardt
authors.forename: Petra
authors.initials: P
authors.lastname: Chmelik
authors.forename: Gunnar
authors.initials: G
authors.lastname: Gaffke
authors.forename: Albrecht
authors.initials: A
authors.lastname: Kretzschmar
authors.forename: Ulrike
authors.initials: U
authors.lastname: Schneider
authors.forename: Roland
authors.initials: R
authors.lastname: Felix
authors.forename: Peter
authors.initials: P
authors.lastname: Hohenberger
mesh_terms: D000005:Abdomen / Q000473:pathology*; D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000627:therapeutic use; D001549:Benzamides; D005260:Female; D005500:Follow-Up Studies; D046152:Gastrointestinal Stromal Tumors / Q000188:drug therapy* / Q000473:pathology*; D006801:Humans; D000068877:Imatinib Mesylate; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010879:Piperazines / Q000627:therapeutic use*; D011379:Prognosis; D011743:Pyrimidines / Q000627:therapeutic use*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016896:Treatment Outcome
chemical_list: D000970:Antineoplastic Agents; D001549:Benzamides; D010879:Piperazines; D011743:Pyrimidines; D000068877:Imatinib Mesylate