MR Imaging of Gene Expression
Ralph Weissleder, MD, PhD

MR image of a mouse with ETR+ (left arrowhead) and ETR- (right arrowhead) flank tumors.. The image is a composite of a T1 weighted spin echo image obtained for anatomic detail with superimposed R2 changes after Tf-MION administration displayed in a color map. Note the difference in R2 changes between the ETR+ and ETR- tumors (asterisks).

This is the first demonstration of using internalizing receptors to image gene expression by MR imaging