With this method irregular RR intervals in cardiac gating during cardiovascular imaging are rejected and then repeated to improve the image quality, whereby the cardiac frequency is used as a basis of the normal heart rate.
The RR interval window determines the percentage variation of the heart rate. Variations of the acquired data outside the window are rejected and not used in the image reconstruction. Also one interval after the arrhytmic beat will be rejected.
Arrhythmia rejection may be inappropriate for patients with certain pathologies, because if the RR interval is constant long, short, long, - all intervals would be rejected. Also a disadvantage is the time consume, but in some cases this function is mandatory, e.g. for diverse retrospective triggered sequences.

From GE Healthcare;
The Signa SP 0.5T™ is an open MRI magnet that is designed for use in interventional radiology and intra-operative imaging. The vertical gap configuration increases patient positioning options, improves patient observation, and allows continuous access to the patient during imaging. The magnet enclosure also incorporates an intercom, patient observation video camera, laser patient alignment lights, and task lighting in the imaging volume.

From GE Healthcare;
the Signa Ovation™ is a patient-friendly open MRI scanner designed not only to handle a typical patient mix, but to accommodate larger patients, patients who are claustrophobic, and others who have difficulty tolerating the close quarters of conventional MR machines.

From Millennium Technology Inc. This open C-shaped MRI system eases patient comfort and technologist maneuverability. This low cost scanner is build for a wide range of applications. The Virgo™ patient table is detachable and moves on easy rolling castors. Able to accommodate patient weights up to 160 kg, the tabletop has a range of motion of 30 cm in the lateral direction and 90cm in the longitudinal direction. Images generated with this scanner can only be viewed (without data loss) on Millennium's proprietary viewing software.

From GE Healthcare;
the New Signa Profile/i is a patient friendly open MRI system that virtually eliminates patient anxiety and claustrophobia, without compromising diagnostic utility.