Assessment of islet graft survival using a 3.0-Tesla magnetic resonance scanner

Some studies have recently described a magnetic resonance (MR) method for detection of iron-labeled islets transplanted into the liver. The aim of this work was to assess the survival of islet graft using a clinical 3.0-T scanner. Islets from Lewis rats were cultured in the presence of iron oxide nanoparticles. One thousand iron-labeled islets were transplanted into the portal vein of diabetic rats. Blood glucose levels were measured daily through day 14 post-transplantation. MR imaging of the same section of the liver was performed on 1, 3, 7, 10, and 14 days post-transplantation. The labeled islets were visualized by MR as distinct hypointensive spots distributed in the liver. There was a linear correlation between the relative value of delta R2* relaxometry multiplied by the cubic diameter (relative value of the iron volume, Ir) and blood glucose level on 14 days post-transplantation in allograft and isograft (P<0.05). The relative value of delta R2* relaxometry, diameter, and number of hypointensive spots could be calculated to assess the survival of the iron-labeled islet grafts. Assessment of iron-labeled islet grafts using a clinical 3.0-T magnetic resonance scanner represents a useful method that has potential for clinical use.