Neurology & Pain Management Coding Alert

Although physicians wishing to bill Medicare for positron emission tomography (PET) scans face a web of ever-changing and seemingly ever-multiplying guidelines, the restrictions may benefit neurologists (in a sense) because they limit PET scan billing to one indication and a single applicable code.

As defined by Medicare decision memorandum CAG-00065N, which anticipates national Medicare policy for PET scans, positron emission tomography "is a noninvasive diagnostic imaging procedure that assesses the level of metabolic activity and perfusion in various organ systems of the human body." For example, a physician can use PET scans of the brain to evaluate patients who have memory disorders of an undetermined cause, who have suspected or proved brain tumors, or (as explained below) who have seizure disorders that are not responsive to therapy and are therefore candidates for surgery.

Since 1995, when CMS (then HCFA) issued its first coverage decision on the technology, Medicare has covered PET scans for more and more indications, including various cancers (lung, skin, breast, etc.), lipomas and metastases. Medicare's increasingly liberal policy toward PET scans reflects in part the continued maturity of the technology (the availability of whole-body scanners and increased computer processing capability, which have improved PET image reconstruction and  display, for example). But at present, the only Medicare-approved indication for PET scans in neurology practice is the presurgical management of patients with refractory seizures, a transient disturbance of cerebral function caused by an abnormal neuronal discharge. According to the Medicare decision memorandum, "Approximately 25 percent of patients with seizure disorders have intractable (or refractory) seizures [and] 12-25 percent of these patients, in turn, are candidates for surgery, having failed medical therapy."

The memorandum goes on to note, "Several non-invasive diagnostic parameters include brain imaging, clinical/physical examination, neuropsychological testing, and surface electroencephalogram (EEG) testing; however, inconclusive testing can warrant invasive monitoring such as EEG with depth and grid electrodes. Therefore, if PET can provide additional non-invasive confirmation of seizure focus localization, then more patients might avoid preoperative invasive EEG."

Medicare has created its own code to report this service: G0229 (PET imaging; metabolic brain imaging for pre-surgical evaluation of refractory seizures). Medicare payers will not reimburse for CPT PET scan codes most closely associated with G0229 78608 (Brain imaging, positron emission tomography [PET]; metabolic evaluation) and 78609 (... perfusion evaluation) although many private payers will.

Although Medicare will cover PET scan presurgical evaluation for refractory (that is, nonresponsive to medication) seizures, it will do so only under rigidly defined conditions. Primarily, the patient record must indicate medical necessity. Specifically, the record must show a history of seizures unresponsive to medical therapy, and "The entity submitting claims for payment must keep such patient records as Medicare requires on file for each patient for which a PET scan claim is made," according to CMS regulations.

The most common diagnosis necessitating presurgical PET scan for refractory seizure is idiopathic epilepsy (345.9x), says Carolyn Cidis Meltzer, MD, associate professor of radiology, psychiatry and neurology, and chief of neuroradiology at the University of Pittsburgh Medical Center in Pittsburgh. Note that 345.9x requires a fifth digit of either "0" (without mention of intractable epilepsy) or "1" (with mention of intractable epilepsy) of course, a diagnosis of intractability is required for reimbursement of PET scans.

Additionally, Medicare coverage as defined by CMS guidelines only allows for PET scans that do not unnecessarily duplicate other covered diagnostic tests and do not involve investigational drugs (or procedures using investigational drugs) as determined by the U.S. Food and Drug Administration, says Melody Mulaik, MSHS, CPC, RCC, a coding specialist with Atlanta-based Coding Strategies Inc.

Finally, as outlined in program memorandum AB-01-168, issued Nov. 27, 2001, the physician must use a PET scan (full-ring or partial-ring) that the FDA has either approved or cleared for marketing to image radionuclides in the body. FDA approval assumes that the system has been cleared to image radionuclides in the body and that "coincident systems" must have the following features: