Contrast enhancement can be quantified in terms of the dynamic MRI parameters initial rate of enhancement (IRE), maximum enhancement (ME), and number of voxels (Nvox) with Plateau and Washout pattern. These parameters are extracted by examining individual signal intensity versus time curves derived from defined regions of interest.
Nvox indicates the number of voxels showing enhancement patterns. It is representative of the size or volume of enhancement and representative of underlying inflammation. The higher the value, the higher the volume .
ME and IRE values quantify the intensity of signal within the enhancing voxels. The absolute values and changes from Baseline in the MRI parameters of IRE, ME, and Nvox of the selected hand and wrist were estimated at Weeks 1, 2, 4, 8, and 16.
The values presented are for Proximal Interphalangeal (PIP) and Metacarpophalangeal (MCP) joints combined. A negative value in Nvox change from Baseline score indicates an improvement.