COMPUTED MODEL OF GADOLINIUM-ENHANCED MRI OF BREAST DISEASE

Objective: Investigation has shown that the most useful MRI finding fo r the detection of breast cancer is enhancement following intravenous contrast. However, many widely different imaging protocols have been u sed. The purpose of this study is to explicate factors that affect the signal intensity of breast lesions after intravenous gadolinium. Meth ods and materials: A computer model was developed using equations base d on published data. The effect of gadolinium on breast tissues was ca lculated using the model with appropriate values for baseline tissue r elaxation times, relaxivity of gadolinium at the given field strength and concentration of gadolinium based on published data, for the TR, T E, flip angle and field strength of several published sequences used f or enhanced breast MRI. Results: The computer model allows comparison of the performance of different sequences, which can be displayed grap hically. These vary in their performance, largely dependent on T1 weig hting. Enhancement is also affected by the baseline of the T1 of the l esion and sensitivity of the sequence to gadolinium. Malignant lesions demonstrate greater observed enhancement than predicted when assuming symmetric distribution of contrast, indicating there is greater accum ulation of gadolinium, accounting for the differential enhancement bet ween benign and malignant lesions. Conclusions: MRI sequences vary gre atly in their demonstration of enhancement after intravenous gadoliniu m contrast. Numerical diagnostic criteria such as % signal intensity c hange must be interpreted with care when using a different sequence th an that on which the criterion was developed. There is preferentially greater accumulation of contrast in malignant lesions, whether due to angiogenesis or altered permeability. (C) 1997 Elsevier Science Irelan d Ltd.