Accelerated ¹⁹F·MRI Detection of Matrix Metalloproteinase-2/-9 through Responsive Deactivation of Paramagnetic Relaxation Enhancement

Table 2

Relaxation times for MMP probes (0.1 mM) with MMP-2/-9 and generic sequence specificity at 14.1 T and at 298 K using v/v 9 : 1 H₂O/D₂O as a solvent.

	Cleavage state	T1 (ms)	(ms)^a
MMP-2/-9-specific sequence	Pre	15.1	<2.6^b
	Post	961	18.2
Generic MMP sequence	Pre	12.8	<2.3
	Post	960	23.8

^aThe value was calculated using the relation, , where is the linewidth of the fluorine peak at full width half maximum. ^bThe inability to properly identify the exact linewidth of the precleaved state due to the broad linewidth; hence, the maximum linewidth is used, yielding a minimum value.