CHOICE OF CONTRAST ENHANCEMENT INDEX FOR DYNAMIC MAGNETIC-RESONANCE MAMMOGRAPHY

Indices are often used in dynamic MRI of the breast to quantitate sign al enhancement within suspicious lesions. Two indices are commonly use d: one calculates the difference in pre- and postcontrast signal inten sity, normalised to a base-line signal intensity such as that of fat ( which does not enhance) whilst the other calculates the ratio of pre- to postcontrast signal intensity, The results of a computational simul ation are presented which demonstrate the superiority of the normalise d signal difference index, based on the criterion that the best index is that which is least influenced by initial tissue T-1. This hypothes is was tested by comparing the two indices in a group of patients with clinical or mammographic suspicion of recurrent breast carcinoma, Of 37 patient examinations using Gadolinium enhanced MRI of the breast, 1 1 patients showed 13 lesions with some degree of enhancement, which we re subsequently diagnosed histologically as either benign or malignant . The normalised signal difference index showed no overlap between the benign and malignant groups, whereas some overlap was observed with t he signal ratio index. The clinical findings are therefore consistent with the results of the computational simulation. Copyright (C) 1996 E lsevier Science Inc.