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Official Description

Brain imaging, positron emission tomography (PET); metabolic evaluation

© Copyright 2026 American Medical Association. All rights reserved.

Common Language Description

Brain imaging using positron emission tomography (PET) is a sophisticated diagnostic procedure that allows for the visualization of metabolic processes in the brain. This technique employs a radiolabeled isotope tracer, commonly fluorodeoxyglucose (FDG), which is a glucose analog. The PET scan detects the emission of positrons from this radioactive substance, enabling the assessment of brain metabolism in real-time. The procedure generates three-dimensional (3-D) images that illustrate how different regions of the brain utilize glucose, which is crucial for understanding various neurological conditions. The varying uptake of the radiolabeled tracer by brain tissues is represented in the PET images through a spectrum of colors and brightness levels, indicating areas of high and low metabolic activity. To initiate the procedure, an intravenous line is established, and the radiolabeled tracer is injected into the patient's circulatory system. Following a specific waiting period to allow the tracer to localize in the brain, the patient is positioned on the imaging table, and the PET scanner is aligned over the head and neck to capture detailed tomographic views of the brain. The physician then interprets the resulting images and compiles a comprehensive written report detailing the findings of the metabolic evaluation.

© Copyright 2026 Coding Ahead. All rights reserved.

1. Indications

The procedure of brain imaging using positron emission tomography (PET) is indicated for various clinical scenarios where metabolic evaluation of the brain is necessary. The following conditions may warrant the use of this imaging technique:

  • Evaluation of Brain Tumors This procedure is utilized to assess the presence, size, and metabolic activity of brain tumors, aiding in diagnosis and treatment planning.
  • Assessment of Neurodegenerative Diseases PET imaging is indicated for the evaluation of conditions such as Alzheimer's disease and other forms of dementia, providing insights into metabolic changes associated with these disorders.
  • Investigation of Seizure Disorders The procedure can help localize areas of abnormal metabolic activity in patients with epilepsy, assisting in surgical planning or management.
  • Evaluation of Cerebral Ischemia PET imaging is used to assess brain metabolism in cases of suspected stroke or transient ischemic attacks, helping to determine the extent of brain tissue affected.

2. Procedure

The procedure for brain imaging using positron emission tomography (PET) involves several critical steps to ensure accurate imaging and evaluation of brain metabolism. The following outlines the procedural steps:

  • Step 1: Establishing Intravenous Access An intravenous line is established in the patient to facilitate the administration of the radiolabeled isotope tracer. This step is crucial for ensuring that the tracer can be delivered directly into the circulatory system efficiently.
  • Step 2: Injection of Radiolabeled Isotope Tracer The radiolabeled isotope tracer, typically fluorodeoxyglucose (FDG), is injected through the established intravenous line. This tracer is designed to mimic glucose, allowing for the assessment of metabolic activity in the brain.
  • Step 3: Waiting Period After the injection, a prescribed waiting period is observed to allow the radiolabeled tracer to circulate and localize in the brain tissue. This period is essential for optimal imaging results, as it ensures that the tracer has adequately reached the target areas of interest.
  • Step 4: Positioning the Patient Once the waiting period is complete, the patient is positioned on the imaging table. The PET scanner is then aligned over the head and neck to prepare for imaging. Proper positioning is vital to obtain clear and accurate tomographic views of the brain.
  • Step 5: Acquisition of Tomographic Views The PET scanner acquires detailed tomographic images of the brain, capturing the emission of positrons from the radiolabeled tracer. These images reflect the metabolic activity of different brain regions, providing valuable diagnostic information.
  • Step 6: Interpretation and Reporting After the imaging is complete, the physician interprets the acquired images and compiles a written report detailing the findings. This report is essential for guiding further clinical management and treatment decisions.

3. Post-Procedure

Post-procedure care following a brain imaging PET scan typically involves monitoring the patient for any immediate reactions to the radiolabeled tracer. Patients are generally advised to hydrate well to help flush the tracer from their system. There are usually no significant restrictions following the procedure, and patients can typically resume normal activities unless otherwise directed by their physician. The results of the PET scan will be discussed with the patient during a follow-up appointment, where the physician will explain the findings and any necessary next steps in their care.

Short Descr BRAIN IMAGING (PET)
Medium Descr BRAIN IMAGING PET METABOLIC EVALUATION
Long Descr Brain imaging, positron emission tomography (PET); metabolic evaluation
Status Code Carriers Price the Code
Global Days XXX - Global Concept Does Not Apply
PC/TC Indicator (26, TC) 1 - Diagnostic Tests for Radiology Services
Multiple Procedures (51) 0 - No payment adjustment rules for multiple procedures apply.
Bilateral Surgery (50) 0 - 150% payment adjustment for bilateral procedures does NOT apply.
Physician Supervisions 09 - Concept does not apply.
Assistant Surgeon (80, 82) 0 - Payment restriction for assistants at surgery applies to this procedure...
Co-Surgeons (62) 0 - Co-surgeons not permitted for this procedure.
Team Surgery (66) 0 - Team surgeons not permitted for this procedure.
Diagnostic Imaging Family 99 - Concept Does Not Apply
APC Status Indicator Procedure or Service, Not Discounted when Multiple
ASC Payment Indicator Radiology service paid separately when provided integral to a surgical procedure on ASC list; payment based on OPPS relative payment weight.
Type of Service (TOS) 4 - Diagnostic Radiology
Berenson-Eggers TOS (BETOS) I1E - Standard imaging - nuclear medicine
MUE 1
CCS Clinical Classification 209 - Radioisotope scan and function studies
26 Professional component: certain procedures are a combination of a physician or other qualified health care professional component and a technical component. when the physician or other qualified health care professional component is reported separately, the service may be identified by adding modifier 26 to the usual procedure number.
PI Positron emission tomography (pet) or pet/computed tomography (ct) to inform the initial treatment strategy of tumors that are biopsy proven or strongly suspected of being cancerous based on other diagnostic testing
TC Technical component; under certain circumstances, a charge may be made for the technical component alone; under those circumstances the technical component charge is identified by adding modifier 'tc' to the usual procedure number; technical component charges are institutional charges and not billed separately by physicians; however, portable x-ray suppliers only bill for technical component and should utilize modifier tc; the charge data from portable x-ray suppliers will then be used to build customary and prevailing profiles
ME The order for this service adheres to appropriate use criteria in the clinical decision support mechanism consulted by the ordering professional
X5 Diagnostic services requested by another clinician: for reporting services by a clinician who furnishes care to the patient only as requested by another clinician or subsequent and related services requested by another clinician; this modifier is reported for patient relationships that may not be adequately captured by the above alternative categories; reporting clinician service examples include but are not limited to, the radiologist's interpretation of an imaging study requested by another clinician
GC This service has been performed in part by a resident under the direction of a teaching physician
MG The order for this service does not have applicable appropriate use criteria in the qualified clinical decision support mechanism consulted by the ordering professional
MH Unknown if ordering professional consulted a clinical decision support mechanism for this service, related information was not provided to the furnishing professional or provider
GA Waiver of liability statement issued as required by payer policy, individual case
PS Positron emission tomography (pet) or pet/computed tomography (ct) to inform the subsequent treatment strategy of cancerous tumors when the beneficiary's treating physician determines that the pet study is needed to inform subsequent anti-tumor strategy
KX Requirements specified in the medical policy have been met
QQ Ordering professional consulted a qualified clinical decision support mechanism for this service and the related data was provided to the furnishing professional
GZ Item or service expected to be denied as not reasonable and necessary
59 Distinct procedural service: under certain circumstances, it may be necessary to indicate that a procedure or service was distinct or independent from other non-e/m services performed on the same day. modifier 59 is used to identify procedures/services, other than e/m services, that are not normally reported together, but are appropriate under the circumstances. documentation must support a different session, different procedure or surgery, different site or organ system, separate incision/excision, separate lesion, or separate injury (or area of injury in extensive injuries) not ordinarily encountered or performed on the same day by the same individual. however, when another already established modifier is appropriate it should be used rather than modifier 59. only if no more descriptive modifier is available, and the use of modifier 59 best explains the circumstances, should modifier 59 be used. note: modifier 59 should not be appended to an e/m service. to report a separate and distinct e/m service with a non-e/m service performed on the same date, see modifier 25.
AQ Physician providing a service in an unlisted health professional shortage area (hpsa)
52 Reduced services: under certain circumstances a service or procedure is partially reduced or eliminated at the discretion of the physician or other qualified health care professional. under these circumstances the service provided can be identified by its usual procedure number and the addition of modifier 52, signifying that the service is reduced. this provides a means of reporting reduced services without disturbing the identification of the basic service. note: for hospital outpatient reporting of a previously scheduled procedure/service that is partially reduced or cancelled as a result of extenuating circumstances or those that threaten the well-being of the patient prior to or after administration of anesthesia, see modifiers 73 and 74 (see modifiers approved for asc hospital outpatient use).
53 Discontinued procedure: under certain circumstances, the physician or other qualified health care professional may elect to terminate a surgical or diagnostic procedure. due to extenuating circumstances or those that threaten the well being of the patient, it may be necessary to indicate that a surgical or diagnostic procedure was started but discontinued. this circumstance may be reported by adding modifier 53 to the code reported by the individual for the discontinued procedure. note: this modifier is not used to report the elective cancellation of a procedure prior to the patient's anesthesia induction and/or surgical preparation in the operating suite. for outpatient hospital/ambulatory surgery center (asc) reporting of a previously scheduled procedure/service that is partially reduced or cancelled as a result of extenuating circumstances or those that threaten the well being of the patient prior to or after administration of anesthesia, see modifiers 73 and 74 (see modifiers approved for asc hospital outpatient use).
76 Repeat procedure or service by same physician or other qualified health care professional: it may be necessary to indicate that a procedure or service was repeated by the same physician or other qualified health care professional subsequent to the original procedure or service. this circumstance may be reported by adding modifier 76 to the repeated procedure or service. note: this modifier should not be appended to an e/m service.
77 Repeat procedure by another physician or other qualified health care professional: it may be necessary to indicate that a basic procedure or service was repeated by another physician or other qualified health care professional subsequent to the original procedure or service. this circumstance may be reported by adding modifier 77 to the repeated procedure or service. note: this modifier should not be appended to an e/m service.
CR Catastrophe/disaster related
GV Attending physician not employed or paid under arrangement by the patient's hospice provider
GW Service not related to the hospice patient's terminal condition
GY Item or service statutorily excluded, does not meet the definition of any medicare benefit or, for non-medicare insurers, is not a contract benefit
MB Ordering professional is not required to consult a clinical decision support mechanism due to the significant hardship exception of insufficient internet access
MC Ordering professional is not required to consult a clinical decision support mechanism due to the significant hardship exception of electronic health record or clinical decision support mechanism vendor issues
MF The order for this service does not adhere to the appropriate use criteria in the clinical decision support mechanism consulted by the ordering professional
Q0 Investigational clinical service provided in a clinical research study that is in an approved clinical research study
Q1 Routine clinical service provided in a clinical research study that is in an approved clinical research study
Q6 Service furnished under a fee-for-time compensation arrangement by a substitute physician or by a substitute physical therapist furnishing outpatient physical therapy services in a health professional shortage area, a medically underserved area, or a rural area
QJ Services/items provided to a prisoner or patient in state or local custody, however the state or local government, as applicable, meets the requirements in 42 cfr 411.4 (b)
XS Separate structure, a service that is distinct because it was performed on a separate organ/structure
Date
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Notes
1994-01-01 Added First appearance in code book in 1994.
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