Aetna considers magnetic resonance imaging (MRI) medically necessary for appropriate indications without regard to the field strength or configuration of the MRI unit.  Aetna considers intermediate and low field strength MRI units to be an acceptable alternative to standard full strength MRI units.

Aetna considers "open" MRI units of any configuration, including MRI units that allow imaging when standing (Stand-Up MRI) or when sitting, to be an acceptable alternative to standard "closed" MRI units.

Aetna considers repeat MRI scans in different positions (such as flexion, extension, rotation and lateral bending) and when done with and without weight-bearing to be experimental and investigational because of insufficient evidence of this approach.

See also: CPB 0094 - Magnetic Resonance Angiography (MRA) and Magnetic Resonance Venography (MRV); CPB 0105 - Magnetic Resonance Imaging (MRI) of the Breast; CPB 0171- MRI of the Extremities; CPB 0236 - MRI and CT of the Spine; CPB 0384 - Magnetic Resonance Cholangiopancreatography; CPB 0387 - Magnetic Resonance Neurography; CPB 0520 - Magnetic Resonance Imaging of the Cardiovascular System - Cardiac MRI.

Standing MRIs (e.g., The Stand-Up^TM  MRI, FONAR, Melville, NY) allows patients to walk in and be scanned while standing.

Standing MRIs are equipped with a system that positions the patient in the magnet and places the anatomy of interest at the center of the magnet gap.  The standing MRI can also rotate a patient from the vertical to the horizontal position so the patient can be scanned lying down.  MRIs have also been developed that can scan patients in a sitting position [Position MRI^TM (pMRI^TM )].

The standing MRI and sitting MRI may be an alternative to open MRI for imaging someone with claustrophobia.

Standing MRIs allows the spine, joints and other parts of the body to be imaged in the weight bearing state.  In theory, if one can scan the patient in a load-bearing position, one can more accurately identify the precise source of pain.  The standing MRI can also image someone in various positions (e.g., flexion, extension, rotation, and lateral bending).  Currently, standing radiographs are used to examine patients in the standing position or other positions.

The clinical value of standing MRI or position MRI imaging in various positions (e.g., flexion, extension, rotation and lateral bending) has not been systematically evaluated in clinical studies.  It has not been demonstrated in published prospective clinical studies that performing MRIs in these various positions can consistently detect problems that can not be detected with a standard MRI.

An assessment of standing, weight-bearing, positional, and upright MRIs by the Washington State Department of Labor and Industries (2006) concluded: "There is limited scientific data available on the accuracy and diagnostic utility of standing, upright, weight-bearing or positional MRI.  Well-designed clinical trials are necessary to effectively determine the potential benefits and value of this diagnostic imaging method. . . . Due to the lack of evidence addressing diagnostic accuracy or diagnostic utility, standing, weight-bearing, positional magnetic resonance imaging is considered investigational and experimental".

Supported by findings of a technology assessment of upright, positional and weight-bearing MRIs (Skelly et al, 2007), the Washington State Health Care Authority found that "there was insufficient scientific evidence to make any conclusions about uMRI’s effectiveness, including whether uMRI: accurately identifies an appropriate diagnosis; can safely and effectively replace other tests; or results in equivalent or better diagnostic or therapeutic outcomes".

Diefenbach et al (2013) examined if an upright positional MRI protocol could produce reliable spinal curvature images and measurements compared with traditional radiograph.  A total of 25 consecutive patients (16 females; 9 males; average age of 14.6 yrs; range of 12 to 18) with a diagnosis of adolescent idiopathic scoliosis (AIS) were enrolled in this study.  Average major curve magnitude was 30° (range of 6 to 70).  Subjects received anterior-posterior as well as lateral plain radiographical scoliosis imaging followed within 1 week by uMRI; MRI data acquisition was performed in less than 7 mins.  Two independent observers performed all Cobb angle, T5-T12 kyphosis, and vertebral rotation measurements for comparison.  The Pearson correlation method was performed to compare radiograph to uMRI measurements, while inter-rater and intra-rater correlations were performed to assess reliability.  These investigators found outstanding correlation between all plain film radiography and uMRI measurements (p = 0.01); major Cobb angles (R = 0.901), minor Cobb angles (R = 0.838), and kyphosis (R = 0.943).  Inter-rater reliability for both radiographical and MRI measurements of major Cobb angles (R = 0.959, 0.896, respectively), minor Cobb angles (R = 0.951, 0.857, respectively), and vertebral rotation (R = 0.945) were outstanding.  Intra-rater reliability for both radiographical and MRI measurements of major Cobb angles (R = 0.966, 0.966, respectively) and minor Cobb angles (R = 0.945, 0.943, respectively) were also outstanding.  The authors concluded that these results showed that uMRI is capable of producing coronal and sagittal plane measurements that highly correlate with traditional plain film radiographical measurements.  This, in addition to reliable vertebral rotation measurements, makes uMRI a valuable, radiation-free alternative/substitute for diagnostic evaluation in AIS.