18F Florbetapir (Amyvid)
Positive Amyvid and Negative scans courtesy of Lillydiagnostics.com
TRACER INFORMATION AND INDICATION
Amyvid was approved in 2012 as a PET imaging agent for the brain to estimate β-amyloid neuritic plaque density in adult patients with cognitive impairment who are being evaluated for Alzheimer’s Disease and other causes of cognitive decline.
Florbetapir works by diffusing across the human blood-brain barrier and is retained in areas that contain β-amyloid aggregates.
CONTRAINDICATIONS
None. Make sure to check with the appropriate MD regarding pregnancy and breastfeeding. Drug interaction studies have not been performed in patients to establish the extent, if any, of altered Amyvid image results. In the in vitro tests done, no drug used was found to interfere with the tracer binding to its target.
PATIENT PREPARATION
None.
RADIOPHARMACEUTICAL
10mCi (370MBq) administered as a bolus in a total volume of 10mL or less. Injection should be followed with an intravenous saline flush. The dose should not be administered if it contains any particulate matter or is discolored.
IMAGING PROTOCOL AND ACQUISITION PARAMETERS
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Imaging can begin 30-50 minutes post Amyvid injection.
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Patient should be supine with the head secured to avoid movement during the exam. The entire brain, including the cerebellum, should be in the field of view.
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Acquire the image for 10 minutes.
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Image reconstruction should include attenuation correction with resulting transaxial pixel sizes between 2 and 3 mm.
BIODISTRIBUTION
One of the limitations of use for Amyvid is that a positive scan does not establish a diagnosis of AD or other cognitive disorder. Therefore, the objective of this scan is to provide an estimate of β-amyloid neuritic plaque density instead of a clinical diagnosis. In other words, a negative scan is inconsistent with a neuropathological diagnosis of AD at the time of image acquisition, and reduces the likelihood of AD. A positive scan may indicate AD, but may also be present in patients with other types of neurologic conditions as well as older people with normal cognition.
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Images are interpreted as positive or negative by comparing the radioactivity in cortical grey matter with the activity in the adjacent white matter. Negative scans show more radioactivity in the white matter compared to the grey matter and positive scans show cortical areas with a reduction or loss of the normally distinct grey-white contrast. Typically, a positive scan will have either two or more brain areas in which there is reduced or absent grey-white contrast or one or more areas in which grey matter has intense tracer uptake that clearly exceeds that of neighboring white matter. Interpretation is also only based on uptake in the cerebral cortex as the uptake in the cerebellum does not contribute to the interpretation.
IMAGE INTERPRETATION
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All lesions with an uptake greater than background are considered as positive, meaning there is evidence of the presence of estrogen receptors ligand-binding function of estrogen receptors. The most commonly used SUV threshold for calling a lesion positive is 1.5, with a range from 1 to 1.8. However, interpretation based solely on quantitative measures should be avoided as many factors such as recent treatments and the partial volume effect can alter SUV values.
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In addition, it should be noted that the uptake of Cerianna is not specific for breast cancer and may occur in a variety of ER-positive tumors that arise outside of the breast. Cerianna should not be used in lieu of biopsy.
HELPFUL INFORMATION FOR TECHNOLOGISTS
For procedure coding for all settings and payers other than medicare, SNMMI recommends one of two CPT codes based on the protocol and equipment utilized. CPT 78811 Positron emission tomography (PET) imaging; limited area (eg, chest, head/neck) or CPT 78814 Positron emission tomography (PET) with concurrently acquired computed tomography (CT) for attenuation correction and anatomical localization imaging; limited area (eg, chest, head/neck). For Radiopharmaceutical coding, with dates of service January 1, 2013 and later, hospital outpatient departments IDTFs, physician offices, and TPPs use the new in 2013 HCPCS Level II code A9586 Florbetapir F-18, diagnostic, per study dose, up to 10 millicuries for F-18 florbetapir. The NDC number for this radiopharmaceutical, #00002-1200-01, may also be requested.
References
CERIANNA (F-18 Fluoroestradiol Injection)[package insert]. Marlborough, MA. Zionexa US Corp. 2022.
CERIANNATM (F-18 labeled Fluoroestradiol, Injection) - SNMMI. (n.d.). https://www.snmmi.org/IssuesAdvocacy/QandADetail.aspx?ItemNumber=33939
Zionexa US Corp. Cerianna Full prescribing information. https://www.cerianna.com/wp-content/uploads/2020/05/cerianna-prescribing-information.pdf. Revised July 2020