DYNAMIC CONTRAST-ENHANCED MRI WITH SUBTRACTION OF AGGRESSIVE SOFT-TISSUE TUMORS AFTER RESECTION

Objective. To report the application of dynamic contrast-enhanced subt raction MRI for detecting recurrences in aggressive or malignant soft tissue tumors. Design. The imaging studies consisted of static (T1- an d T2-weighted spin-echo) acquisitions, followed by dynamic conventiona l spin-echo short TR/TE images (at 45 s, 1 min 30 s and 5 min) after a bolus of intravenous contrast medium. Contrast images were subtracted from the precontrast scan on the console. Patients. Ninety-eight pati ents were studied who had had aggressive or malignant soft tissue tumo rs treated by surgery, and were followed up to assess recurrences. Res ults. Subtraction MRI characterized recurrences better than routine se quences in 10 patients (1 lesion was seen only with this technique, 6 were better delineated, and 3 inflammatory pseudotumors were identifie d), and less well in 4 cases. Conclusion. As the number of levels stud ied on dynamic images is limited, and all but one recurrence were dete cted on T2-weighted images, it remains logical to start the examinatio n with T2-weighted spin-echo images, and to use the dynamic study only if contrast injection is required.