Functional Magnetic Resonance Imaging of the Brain for Presurgical Mapping or Seizure Focus Localization

POLICY NUMBER

L.6.01.423

DESCRIPTION

Functional magnetic resonance imaging (fMRI) is a noninvasive method for localizing areas of brain function and has been used for the presurgical evaluation of eloquent brain areas. Using this method, images are collected while specific activities are performed to assist in the localization of critical cortical areas, as well as the evaluation of language lateralization. Functional magnetic resonance imaging is also being investigated in combination with diffusion tensor imaging and electroencephalography (EEG) to identify seizure focus.

Functional Magnetic Resonance Imaging

Functional magnetic resonance imaging (fMRI) is an activation method that uses sequences based on T2-weighted blood oxygen level-dependent response. These studies are often done on magnetic resonance scanners with field strengths of 1.5 tesla or greater. The interhemispheric difference between activated volumes in the left and right hemispheric regions of interest is calculated as the laterality index, which ranges from -1 to 1. A positive laterality index is considered left-dominant, while a negative laterality index is right-dominant. Laterality indexes determined by fMRI may be derived for several different functional areas (regions of interest) that include either the Broca area (language production) or the Wernicke area (language comprehension). Various thresholds (e.g., -0.1 to +0.1, or -0.5 to +0.5) have been proposed to differentiate laterality from bilaterality. Bilateral activation patterns can result from the detection of the language-associated, but not the language-essential cortex. Therefore, bilateral activation is not necessarily indicative of a bilateral distribution of language-essential cortex and may be task-dependent. In addition, sensitivity and specificity may change with the application of different statistical thresholds.

Simultaneous electroencephalography (EEG) and fMRI are being investigated for the localization of seizures. Simultaneous EEG-fMRI combines the temporal resolution of EEG and the spatial resolution of fMRI. Simultaneous EEG-fMRI may allow for the detection of cerebral hemodynamic changes associated with seizures and interictal epileptiform discharges that are identified on scalp EEG. Another potential use of simultaneous EEG-fMRI is to facilitate the implantation strategy of invasive subdural electrodes.

Several fMRI hardware (eg, fMRI Hardware System; NordicNeuroLab AS) and fMRI software packages (eg, BrainAcquireRx™/BrainProcessRx™ Data Suite; Kyron Clinical Imaging) have been cleared for marketing by the U.S. Food and Drug Administration (FDA) through the 510(k) process for use with an MRI scanner to perform fMRI.

POLICY

Functional MRI may be considered medically necessary as a complementary test in the preoperative evaluation of individuals with refractory epilepsy or brain tumors who are candidates for neurosurgery when the lesion is in close proximity to an eloquent area of the brain (e.g., controlling verbal or motor function) and testing is expected to have an important role in assessing the spatial relation between the lesion and eloquent brain area.

Functional MRI is considered investigational for all other applications.

POLICY EXCEPTIONS

Federal Employee Program (FEP) may dictate that all FDA-approved devices, drugs or biologics may not be considered investigational and thus these devices may be assessed only on the basis of their medical necessity.

POLICY GUIDELINES

The coverage guidelines outlined in the Medical Policy Manual should not be used in lieu of the Member's specific benefit plan language.

Medically Necessary is defined as those services, treatments, procedures, equipment, drugs, devices, items or supplies furnished by a covered Provider that are required to identify or treat a Member's illness, injury or Mental Health Disorders, and which Company determines are covered under this Benefit Plan based on the criteria as follows in A through D:

A.  consistent with the symptoms or diagnosis and treatment of the Member's condition, illness, or injury; and

B.  appropriate with regard to standards of good medical practice; and

C.  not solely for the convenience of the Member, his or her Provider; and

D.  the most appropriate supply or level of care which can safely be provided to Member. When applied to the care of an Inpatient, it further means that services for the Member's medical symptoms or conditions require that the services cannot be safely provided to the Member as an Outpatient.

For the definition of medical necessity, “standards of good medical practice” means standards that are based on credible scientific evidence published in peer-reviewed medical literature generally recognized by the relevant medical community, and physician specialty society recommendations, and the views of medical practitioners practicing in relevant clinical areas and any other relevant factors. BCBSMS makes no payment for services, treatments, procedures, equipment, drugs, devices, items or supplies which are not documented to be Medically Necessary. The fact that a Physician or other Provider has prescribed, ordered, recommended, or approved a service or supply does not in itself, make it Medically Necessary.

Investigative is defined as the use of any treatment procedure, facility, equipment, drug, device, or supply not yet recognized as a generally accepted standard of good medical practice for the treatment of the condition being treated and; therefore, is not considered medically necessary. For the definition of Investigative, “generally accepted standards of medical practice” means standards that are based on credible scientific evidence published in peer-reviewed medical literature generally recognized by the relevant medical community, and physician specialty society recommendations, and the views of medical practitioners practicing in relevant clinical areas and any other relevant factors. In order for equipment, devices, drugs or supplies [i.e, technologies], to be considered not investigative, the technology must have final approval from the appropriate governmental bodies, and scientific evidence must permit conclusions concerning the effect of the technology on health outcomes, and the technology must improve the net health outcome, and the technology must be as beneficial as any established alternative and the improvement must be attainable outside the testing/investigational setting.

POLICY HISTORY

12/21/2006: Policy added.

3/22/2007: Reviewed and approved by the Medical Policy Advisory Committee (MPAC).

6/19/2009: Policy reviewed, policy statement re-written for clarity.

07/09/2010: Policy description updated regarding use of functional MRI. Added "as a complementary test" to the policy statement; intent unchanged. FEP verbiage added to the Policy Exceptions section.

08/02/2011: Policy reviewed; no changes.

07/17/2012: Policy reviewed; no changes.

10/17/2013: Policy reviewed; no changes.

07/31/2014: Policy reviewed; description updated regarding direct intracortical electrical stimulation and the Wada test. Medically necessary policy statement revised to change "is considered" to "may be considered."

08/28/2015: Medical policy revised to add ICD-10 codes. Code descriptions updated for CPT code 96020 and ICD-9 diagnosis code 198.3 in the Code Reference section.

10/20/2015: Policy description updated regarding the use of EEG-fMRI. Policy statements unchanged. Policy guidelines updated to add medically necessary and investigative definitions.

05/31/2016: Policy number A.6.01.47 added.

10/13/2016: Policy title changed from "Functional Magnetic Resonance Imaging (MRI)" to "Functional Magnetic Resonance Imaging of the Brain." Policy description updated. Policy statements unchanged.

10/18/2017: Policy description updated regarding presurgical brain mapping. Policy statements unchanged.

10/05/2018: Policy reviewed; no changes.

10/22/2019: Policy description revised. Policy statements unchanged.

10/14/2020: Policy reviewed; no changes.

12/30/2021: Policy reviewed. Policy statements unchanged. Policy Guidelines updated to change "Nervous/Mental Conditions" to "Mental Health Disorders" and "Medically Necessary" to "medical necessity."

12/01/2022: Policy reviewed. Policy statement updated to change "patients" to "individuals."

09/29/2023: Code Reference section updated to add new ICD-10 diagnosis codes G40.C01, G40.C09, G40.C11, and G40.C19, effective 10/01/2023.

10/12/2023: Policy reviewed; no changes.

01/31/2025: Policy title changed from "Functional Magnetic Resonance Imaging of the Brain" to "Functional Magnetic Resonance Imaging of the Brain for Presurgical Mapping or Seizure Focus Localization." Medical policy number changed from "A.6.01.47" to "L.6.01.423." Policy reviewed. Policy statements unchanged.

SOURCE(S)

Blue Cross Blue Shield Association Policy # 6.01.47

CODE REFERENCE

This may not be a comprehensive list of procedure codes applicable to this policy.

The code(s) listed below are ONLY medically necessary if the procedure is performed according to the "Policy" section of this document.

Covered Codes

CPT copyright American Medical Association. All rights reserved. CPT is a registered trademark of the American Medical Association.