K. Orangkhadivi et al., NEW MAGNETIC-RESONANCE-IMAGING TECHNIQUES FOR THE DETECTION OF BREAST-CANCER, Breast cancer research and treatment, 32(1), 1994, pp. 119-135
The importance of contrast agents in enhancing diagnoses from magnetic
resonance images has been established in numerous cases. However, the
development of a potent tissue-specific contrast agent, as a sensitiv
e probe for early detection and investigation of the physiological cha
racteristics of a tumor, has not yet been realized in MR imaging (MRI)
. In nuclear scintigraphy the technique has been demonstrated; however
, the poor spacial resolution inherent to the modality and the substan
tial dose of radioactivity administered to the patient has hindered it
s widespread use. This article will review the different classes of co
ntrast agents in MRI, with special focus on the strategies involved in
the development of targeted tissue-specific MRI contrast agents for t
he early detection of breast cancer. The features of a new class of co
ntrast agents for targeted MR imaging will be described. Gadolinium-co
ntaining melanin polymers (GMP's) have been synthesized as MR contrast
agents in our laboratory. These GMP's demonstrate significantly highe
r relaxivities than any other paramagnetic contrast agents reported; c
onsequently, they are extremely effective contrast enhancing, imaging
agents by themselves. The successful coupling of these potent GMP's to
a monoclonal antibody specific for breast carcinoma, the 323/A3 monoc
lonal antibody, suggests that in vivo tissue-specific MR imaging, at t
he receptor level, will become feasible in the near future.