La. Admin. Code tit. 48 § I-11533

Current through Register Vol. 50, No. 11, November 20, 2024

Section I-11533 - Magnetic Resonance Imaging

A. Definition/Description

1. Magnetic resonance imaging (MRI), also referred to as Nuclear magnetic resonance, is a diagnostic technique that employs magnetic and radio frequency fields to image body tissue and monitor body chemistry noninvasively. The basic principle of this modality involves the magnetizing of the hydrogen nuclei of the body which then become aligned, while spinning, in the direction of the magnetic field. A variable wobble is produced in the nuclei spin by a pulsating radio frequency current directed at a 90 degree angle to the magnetic field. The small voltage of a resulting electrical current is detected by a surface coil receiver and relayed to a computer for analysis.

2. Although different in principle there is some similarity between magnetic resonance imaging and computer assisted tomography (CT). These similarities are associated with the purposes, uses, and output of the two modalities. Both are diagnostic modalities. Both are imaging devices capable of soft tissue scanning, although each demonstrates advantages specific to certain tissues, organs, and lesions. Finally, both produce cross-sectional images. Because of these similarities there is some overlap in capabilities of the two and the extent of this overlap appears to be increasing as magnetic resonance imaging becomes more refined. This has led to some speculation that MRI may supplant CT in the future.

3. However, there also exist some fundamental differences between the modalities. Among these differences are the facts that 1) MRI is not a radiation-based technology, 2) MRI has no moving parts, 3) parameters measured by MRI relate to tissue chemistry and 4) MRI is superior in lesion detection while CT provides greater anatomical information.

4. In applying planning strategies in the area of magnetic resonance imaging, there are several critical definitions which must be established. These are:

a.MRI Procedure or Scan is one discrete MRI study of one patient in one visit regardless of the number of tissues, organs or lesions examined in that one study.

b.MRI Unit is considered to be all of the essential equipment and facilities necessary to operate one MRI suite.

c.Service Area is defined as the health planning district in which the MRI is or will be located.

B. Use

1. MRI has been used in chemical analysis for some 30 years. Medical application has a much shorter history and the potential of the technique in this field has not been fully realized. An examination of its use, then, must distinguish between those applications which have been demonstrated to be efficacious and those which seem to have the potential to become efficacious. Addressing the first category, MRI, as an imaging device, has been demonstrated to be superior for scanning selected body parts such as the brain, brain stem, and spinal cord. MRI has the capability of providing better differentiation of gray and white matter than does CT scanning. Contributing to this capability is the fact that the Min image is unobstructed by bone. This property makes it particularly useful for head scans and, thus, for assessing neurological disease. This property also gives MRI an advantage over other imaging techniques in certain spinal cord and back injury cases including disc disease. A final property of MRI that bears mentioning in respect to its demonstrated clinical applications is its ability to image along the sagittal plane as well as the coronal and oblique planes. CT scanners do not enjoy this versatility, although their computer programs can reformat data to provide a sagittal view.

2. Moving to the category of potential uses of MRI, those receiving the greatest attention are related to the modality's capacity to analyze biochemical states. It is felt that, with additional research, it should become possible to distinguish between healthy and malignant tissues and to monitor chemical changes during therapy. Other potential applications include the detection of metastasis, measurement of blood flow rates from various organs, diagnosis of liver and kidney disease, determination of rejection of transplants and non-invasive heart studies.

C. Issues

1. Perhaps reflective of the relative recency of MRI's medical applications, there are a number of issues involved in its use. One of the more prominent categories of these issues consists of those related to safety and risks.

2. Because of the noninvasive quality of the modality, some feel that risks may be minimal. However, this quality is not an unmitigated asset, as it results in the technology falling outside the authority of such regulatory bodies as the Nuclear Energy Division of the Nuclear Regulatory Commission.

3. The Food and Drug Administration has the responsibility of determining whether an MRI device presents serious risks or a potential for serious risk to the health, safety or welfare of a subject. This agency has classified MRI as a Class III device, subject to the greatest degree of control. Formal premarket approval for each model is required prior to its being marketed in order to assure its safety and effectiveness. A number of safety issues escape this mechanism of protection, however. As examples, the magnetic field may interfere with cardiac pacemakers and produce movement of ferromagnetic aneurysm clips and heart valves which attempt to align with the magnetic field much as a compass needle does. It is also possible that the attraction of the magnetic field for metal objects such as hemostats, scissors, wrenches, and knives may be so strong that they may become dangerous projectiles as they move through the field. Additionally, the magnetic field may induce electrical currents within the body of the subject. Some risk may also be attributable to the radio-frequency field which, in the case of subjects with large ferrometal prostheses, may cause an elevation in temperature, and empirical evidence suggests that the testes and the lens of the eye may be particularly vulnerable to adverse effects.

4. Issues related to costs constitute another category. These issues include the large initial cost both of the device and the unit. Related issues, however, must include the extent to which such an investment in new technology should be condoned when there is existing technology that can provide many of the same functions; whether the technology should be considered a regional rather than a facility resource; and how the cost is to be reimbursed, especially prior to the time that the modality is declared safe and effective in the diagnosis and treatment of patients. Also related to cost, is the possibility that when MRI receives the approval of the Food and Drug Administration, the approval will probably be for specific clinical applications, thus raising the question of whether these limited procedures will generate enough volume to warrant the establishment of MRI units for clinical, nonresearch purposes in all types of hospitals.

D. Costs

1. The actual costs of MRI units are considerable and vary according to unique considerations. The most critical cost factor is the type of magnet purchased, with quoted costs ranging from $1 million to $1.7 million. Added to this are site preparation costs which may range from $300,000 to $1 million, again, depending partly on the type of magnet selected as well as the nature of the renovation or construction required. These several values suggest that the start-up costs for an MRI unit should not exceed $2.7 million. However, it is not uncommon for actual costs to exceed this amount. Operating costs can be expected to vary from $220,000 to $400,000 per year and the cost per procedure is projected to be around $500.

E. Resource Goals

1. The applicant shall document a projection of an annual utilization of at least 2,000 MRI procedures.

2. Demographics, patient referral patterns, patient accessibility and relationships with existing providers and facilities within the proposed primary service area are important determinants for MRI site selection.

a. A written plan specifically addressing MRI referrals must be presented with the application, in which it is established that the applicant is committed to accept appropriate referrals from other local providers and to provide feedback of patient information to the referring physician and facility.

b. The above documentation must establish that patients will be prioritized according to standards of need and appropriateness rather than source of referral.

3. Proposed MRI units must be located in facilities which have, either in-house or through formal referral arrangements, the resources necessary to treat most of the conditions diagnosed or confirmed by MRI. The following medical specialties must be available during normal working hours on-site, or by formal referral arrangements: neurology, neurosurgery, oncology and cardiology.

4. Applicants must demonstrate proposed staffing patterns appropriate to the nature of the unit. All units must be staffed by: a diagnostic radiologist familiar with a range of imaging techniques, who must have a background in MRI; a physicist knowledgable in the operational parameters of MRI systems; technicians trained in MRI procedures; and a medical statistician or data base manager. Units to be used for experimental research must also be staffed by specialists in the particular field of experimentation.

5. Applicants must demonstrate adequate safety precautions and these must include: documentation that the proposed model has been approved by the Food and Drug Administration as a class I, class II or class III device under 21 USC 360 c-k; itemized safety precautions including screening of at-risk patients, metal detection, and emergency procedures; assurance that all safety recommendations of the manufacturer of the MRI unit will be complied with; a safety manual; and a plan for inservice training. Utilization must be subject to adequate peer review.

La. Admin. Code tit. 48, § I-11533

Promulgated by the Department of Health and Human Resources, Office of Management and Finance, LR 13:246 (April 1987).

AUTHORITY NOTE: Promulgated in accordance with P.L. 93-641 as amended by P.L. 96-79, and R.S. 36:256(b).