Figure 18. Retention valve. T2-weighted fast spin-echo silicone-suppressed MR image of Heyer-Schulte Style 1200 (or 1300) saline-filled breast implant with a retention valve, showing a cross section through the proximal round neck of the valve (short arrow). A peripheral fold is also seen (long arrow). A photograph of a valve of this type is shown in Figure 17, and the MR imaging appearance of the distal flat part of this valve is shown in Figure 19.