To be optimal, a peritoneal dialysis prescription should consider the peritoneal surface area recruitment. In fact, as shown by computed tomography imaging, only a fraction of the available anatomic peritoneum is in contact with the dialysate (PDF). Various factors may dynamically affect the recruitment of the wetted membrane: posture, fill volume, PDF composition (biocompatibility), and pharmacologic agents (phospholipids). To precisely determine the peritoneal membrane recruitment capacity, we developed an animal model. In 5/6 bi-nephrectomized rats on peritoneal dialysis, between week 6 and week 8 post surgery, we used MRI to assess the contact area, with the dialysate acting as the contrast medium (fill volume: 10 mL per 100-g rat body weight). The MRI protocol consisted of axially oriented, turbo spin-echo, 3-mm slice, T2 weighted sequences. The contact area was measured using an adapted three-dimensional MRI reconstruction software based on DICOM (digital imaging and communications in medicine) images. The MRI studies (n=10) were successful. They showed that only a fraction of the presumed anatomic area (30% - 40%) was in contact with the PDF Peritoneal MRI in rats is a method that shows potential for assessing peritoneal contact area and its variation under experimental conditions.