Medical Policy


Subject: Functional Magnetic Resonance Imaging
Document #: RAD.00051 Publish Date:    02/28/2018
Status: Reviewed Last Review Date:    01/25/2018


This document addresses functional magnetic resonance imaging which is an imaging procedure where a magnetic resonance image is produced while a part of the body is in use. This type of imaging is used to evaluate the proximity of a brain lesion to brain tissue responsible for specific functions such as speech, vision, sensation and movement. Knowledge of the potentially impacted functional areas is primarily used in preoperative planning for neurosurgery.

Position Statement

Medically Necessary:

Functional magnetic resonance imaging is considered medically necessary in the evaluation of individuals for whom craniotomy is being considered, when both of the following criteria have been met:

Investigational and Not Medically Necessary:

Functional magnetic resonance imaging is considered investigational and not medically necessary for all other applications.


The use of functional magnetic resonance imaging (fMRI) has been evaluated in several studies for use in localizing eloquent brain areas prior to neurosurgery for epilepsy and tumor resection. 

A study by Woermann and colleagues in 2003 discussed the results of fMRI versus the Wada test in the determination of language dominance in 100 subjects with different localization-related epilepsies. The authors found 91% concordance between tests. The overall rate of incorrect results from fMRI was found to be 9% with a range of 3% in left-sided temporal lobe epilepsy (TLE) to 25% in left-sided extratemporal epilepsy.

One study by Medina and colleagues (2005) summarized the use of fMRI in 53 subjects undergoing surgery for seizure disorders. They reported a high degree of concordance of language lateralization of fMRI and either Wada test or intraoperative cortical stimulation (IOC). Overall, they reported that fMRI was concordant with the Wada test in 78 of 83 (94%) cases and with IOC in 23 of 26 (88%) cases. In 53 of the study participants, language mapping was performed, in 33 motor mapping, and in 7 visual mapping. The fMRI study revealed change in anatomic location or lateralization of language-receptive (Wernicke) in 28% of subjects and in language-expressive (Broca) in 21%. In 38 (63%) subjects, fMRI helped to avoid further studies, including the Wada test. In 31 (52%) and 25 (42%) subjects, intraoperative mapping and surgical plans, respectively, were altered because of fMRI results.

Sabsevitz and colleagues (2003) reported on a series of 24 consecutive subjects who underwent both fMRI and Wada testing before left anterior temporal lobectomy for seizure disorders. While both tests were predictive of language changes, in this study fMRI had a sensitivity of 100% and specificity of 57%, while results for the Wada test were 100% and 43% respectively.

Petrella and colleagues (2006) reported on the impact of fMRI preoperatively on 39 consecutive subjects with brain tumors. In 4 subjects, additional tests, for example, the Wada test, were not ordered because of the fMRI result. Treatment plans differed in 19 subjects after fMRI with a more aggressive approach recommended after imaging in 18 subjects. The impact of the altered treatment plans on health outcomes was not assessed. fMRI resulted in reduced surgical time for 22 subjects; it also led to decisions to perform craniotomy in 13 subjects where less invasive approaches had been initially planned.

The sensitivity and specificity of fMRI compared to the Wada test was calculated in a meta-analysis of 13 studies involving a total of 240 participants (Medina, 2007). When using the pooled Wada test data as the reference, fMRI was found to have a high correlation, reflected by both a sensitivity and specificity of 92.5%. The authors reported that fMRI had the highest accuracy in individuals without epilepsy regardless of hand dominance. The lowest accuracy was found in individuals without epilepsy with left hand dominancy. Concordance at 81-83% was considered high by the authors.

Studies show that fMRI is comparable to the Wada test and intraoperative cortical stimulation in localizing certain eloquent brain areas; although there are less data for direct electrical stimulation. In individuals who are to undergo neurosurgery for seizures or brain tumors, fMRI may significantly impact presurgical planning. However, the impact of fMRI on other outcomes in these individuals is uncertain.

fMRI has also been proposed for a wide variety of other medical conditions, including for various conditions of the spine. The available data on such uses is insufficient to allow reasonable conclusions regarding the safety and efficacy of fMRI in these circumstances. fMRI has also been proposed for study of autism spectrum disorders (Phillip, 2012) and Parkinson’s disease (Knight, 2015; Subramanian, 2012). However current literature is limited to small group sizes and in the case of autism, study participants have not been representative of the general population.


In specific types of brain surgery, such as for seizure disorders or removal of some types of brain tumors, there is increased potential for damage or disruption of structures adjacent to the area of surgical interest. Although the general locations of certain areas of the brain, such as language and motor centers (referred to as “eloquent areas”), are well known, there is some variability from individual to individual. Additionally, the location of these areas may be altered due to some conditions such as the presence of a tumor. Because eloquent areas of the brain are commonly found adjacent to specific types of epileptic foci and brain tumors, it is very important to be able to locate these areas to minimize or avoid damage or disruption to these areas.

There are several methods that may be used to identify eloquent areas of the brain, including the Wada test and direct electrical stimulation. The Wada test involves angiography and injection of a drug into the carotid artery, which puts part of the brain to sleep. While the brain is under the effects of the drug, a physician runs specific task-related tests. Direct electrical stimulation involves surgical placement of electrodes into the brain when the individual is on the operating table. The electrodes are used to stimulate various parts of the brain to allow the surgeons to identify and mark specific areas of importance. Both of these tests are invasive, involve significant amounts of time, and require involvement of various specialists.

fMRI has been proposed as a noninvasive alternative method for location of eloquent brain areas. fMRI measures the rapid metabolic changes that occur in the brain during activity. Images of the brain that are taken during fMRIs are done by imaging the brain using sequential MRI images collected as the individual is asked to conduct specific language, memory or motor activities. These activities cause blood flow to increase in the parts of the brain being used during these activities, allowing for their identification and location. The images are then processed by computer and interpreted by a physician. This information may then be used in surgical planning.

Other uses for fMRI have been proposed, aside from its use in neurosurgical procedures. However, such use has not been subject to robust scientific studies at this time, and the utility of fMRI results under these circumstances is unclear.


Craniotomy: A hole made in an individual’s skull that is used to gain access to the brain during neurosurgical procedures.

Eloquent cortex: Areas of the brain cortex responsible for control of speech, language, sensation, motion, visual and other complex functions.

Functional Magnetic Resonance Imaging (fMRI): An imaging procedure where an MRI is produced while a part of the body is in use. 


The following codes for treatments and procedures applicable to this document are included below for informational purposes. Inclusion or exclusion of a procedure, diagnosis or device code(s) does not constitute or imply member coverage or provider reimbursement policy. Please refer to the member's contract benefits in effect at the time of service to determine coverage or non-coverage of these services as it applies to an individual member.

When services may be Medically Necessary when criteria are met:




Magnetic resonance imaging, brain, functional MRI; including test selection and administration of repetitive body part movement and/or visual stimulation; not requiring physician or psychologist administration


Magnetic resonance imaging, brain, functional MRI; including test selection and administration of repetitive body part movement and/or visual stimulation; requiring physician or psychologist administration of entire neurofunctional testing


Neurofunctional testing selection and administration during noninvasive imaging functional brain mapping, with test administered entirely by a physician or other qualified health care professional (ie, psychologist), with review of test results and report



ICD-10 Diagnosis



Malignant neoplasm of brain


Secondary malignant neoplasm of brain


Benign neoplasm of brain


Neoplasm of uncertain behavior of brain


Neoplasm of unspecified behavior of brain


Epilepsy and recurrent seizures

When services are Investigational and Not Medically Necessary:
For the procedure and diagnosis codes listed above when criteria are not met or for all other diagnoses not listed; or when the code describes a procedure indicated in the Position Statement section as investigational and not medically necessary.


Peer Reviewed Publications:

  1. Knight EJ, Testini P, Min HK, et al. Motor and nonmotor circuitry activation induced by subthalamic nucleus deep brain stimulation in patients with Parkinson disease: intraoperative functional magnetic resonance imaging for deep brain stimulation. Mayo Clin Proc. 2015; 90(6):773-785.
  2. Medina LS, Bernal B, Dunoyer C, et al. Seizure disorders: functional MR imaging for diagnostic evaluation and surgical treatment – prospective study. Radiology. 2005; 236(1):247-253. 
  3. Medina LS, Bernal B, Ruiz J. Role of functional MR in determining language dominance in epilepsy and nonepilepsy populations: a Bayesian analysis. Radiology. 2007; 242(1):94-100.
  4. Petrella JR, Shah LM, Harris KM, et al. Preoperative functional MR imaging localization of language and motor areas: effect on therapeutic decision making in patients with potentially resectable brain tumors. Radiology. 2006; 240(3):793-802.
  5. Philip RC, Dauvermann MR, Whalley HC, et al. A systematic review and meta-analysis of the fMRI investigation of autism spectrum disorders. Neurosci Biobehav Rev. 2012; 36(2):901-942.
  6. Sabsevitz DS, Swanson SJ, Hammeke TA, et al. Use of preoperative functional neuroimaging to predict language deficits from epilepsy surgery. Neurology. 2003; 60(11):1788-1792.
  7. Shinoura N, Yamada R, Suzuki Y, et al. Functional magnetic resonance imaging is more reliable than somatosensory evoked potential or mapping for the detection of the primary motor cortex in proximity to a tumor. Stereotact Funct Neurosurg. 2007; 85(2-3):99-105.
  8. Stancanello J, Cavedon C, Francescon P, et al. BOLD fMRI integration into radiosurgery treatment planning of cerebral vascular malformations. Med Phys. 2007; 34(4):1176-1184.
  9. Subramanian L, Hindle JV, Johnston S, et al. Real-time functional magnetic resonance imaging neurofeedback for treatment of Parkinson's disease. J Neurosci. 2011; 31(45):16309-16317.
  10. Woermann FG, Jokeit H, Luerding R, et al. Language lateralization by Wada test and fMRI in 100 patients with epilepsy. Neurology. 2003; 61(5):699-701. 

Government Agency, Medical Society, and Other Authoritative Publications:

  1. American Academy of Neurology. Practice guideline summary: Use of fMRI in the presurgical evaluation of patients with epilepsy: report of the guideline development, dissemination, and implementation subcommittee of the American Academy of Neurology. Neurology. 2017; 88(4):395-402.
  2. American College of Radiology. ACR Appropriateness Criteria®. Seizures and Epilepsy. 2014. Available at: Accessed on December 21, 2017.
  3. American College of Radiology. Practice Parameter for the Performance of Functional Magnetic Resonance Imaging (fMRI) of the Brain. 2012. Revised 2017. Available at: Accessed on December 21, 2017.

Functional Magnetic Resonance Imaging
Functional MRI

Document History






Medical Policy & Technology Assessment Committee (MPTAC) review. The document header wording updated from “Current Effective Date” to “Publish Date.” Updated References section.



MPTAC review. Updated formatting in Position Statement section. Removed abbreviations from title and Position Statement section.



MPTAC review. Updated Rationale and References sections. Removed ICD-9 codes from Coding section.



MPTAC review. Updated References.



MPTAC review.



MPTAC review. Updated Rationale and References.



MPTAC review. Updated References.



MPTAC review.



MPTAC review.



MPTAC review.



MPTAC review. The phrase “investigational/not medically necessary” was clarified to read “investigational and not medically necessary.” This change was approved at the November 29, 2007 MPTAC meeting.



MPTAC review. Initial document development.