Amyvid Injection Dosage

Recommended Dosage

The recommended amount of radioactivity of AMYVID is 370 MBq (10 mCi) in a total volume of up to 10 mL, administered as a single intravenous bolus. The maximum mass dose is 50 mcg. Follow the injection with an intravenous flush of approximately 10 mL of 0.9% sodium chloride injection.

Patient Preparation

Instruct patients to hydrate before and after AMYVID administration and to void following AMYVID administration before imaging and frequently thereafter.

Administration

• Use aseptic technique and radiation shielding when withdrawing and administering AMYVID.
• Visually inspect AMYVID for particulate matter and discoloration prior to administration. Do not use AMYVID if it contains particulate matter or if it is discolored.
• Do not dilute AMYVID.
• Assay the dose in a dose calibrator prior to administration.
• Inject AMYVID through a short intravenous catheter (approximately 1.5 inches or less) to minimize the potential for adsorption of the drug to the catheter. Portions of the AMYVID dose may adhere to longer catheters.
• Dispose of unused product in a safe manner in compliance with applicable regulations.

Image Display

• Display images in the transaxial orientation with access as needed to the sagittal and coronal planes.
• In reviewing the images, include all transaxial slices of the brain using a black-white scale set to the maximum intensity of all the brain pixels.
• Initially locate the brain slice with the highest levels of image contrast (highest signal intensity) and adjust the contrast appropriately.
• Start image interpretation by displaying slices sequentially from the bottom of the brain to the top. Periodically refer to the sagittal and coronal plane image display as needed to better define the signal intensity and to ensure that the entire brain is displayed.

Visual Assessment

AMYVID images should be interpreted only by readers who successfully complete the training program provided by the manufacturer.

Perform image interpretation independently of the patient's clinical features, relying on the recognition of unique image features.

Interpret AMYVID images based upon the distribution of signal intensity within the cerebral cortex by comparing the signal intensity in the cortical gray matter and the adjacent white matter. The signal intensity in the cerebellum does not contribute to the scan interpretation. For example, a positive scan may show retained cerebellar gray-white contrast even when the cortical gray-white contrast is lost.

Some scans may be difficult to interpret due to image noise, atrophy with a thinned cortical ribbon, or image blur. For cases where there is uncertainty as to the location of cortical signal, use co-registered anatomical imaging to improve localization of signal.

Positive AMYVID Scan

Positive scans show cortical areas with reduction or loss of the normally distinct gray-white contrast. These scans will have one or more areas with increased cortical gray matter signal which results in reduced (or absent) gray-white contrast. Specifically, a positive scan will have either:

a)

Two or more brain areas (each larger than a single cortical gyrus) in which there is reduced or absent gray-white contrast. This is the most common appearance of a positive scan.
or

b)

One or more areas in which cortical gray matter signal is intense and clearly exceeds the signal in adjacent white matter.

A positive scan establishes the presence of moderate to frequent amyloid beta neuritic plaques. Neuropathological examination has shown that moderate to frequent amyloid beta neuritic plaques are present in patients with AD, but may also be present in patients with other types of neurologic conditions as well as older people with normal cognition.

Figures 1, 2, and 3 provide examples of negative and positive scans.

Figure 1: Examples of AMYVID negative scans (top two rows) and positive scans (bottom two rows). Left to right panels show sagittal, coronal, and transverse PET image slices. Final panel to right shows an enlarged picture of the brain area under the box. The top two arrows are pointing to normal preserved gray-white contrast with cortical signal intensity less than the adjacent white matter. The bottom two arrows indicate areas of decreased gray-white contrast with increased cortical signal intensity that is comparable to the intensity in the adjacent white matter.

Figure 2: Typical Negative Scan. The upper (top) and lower (bottom) transverse slices both show good gray-white matter contrast. The dotted lines illustrate the edge of the cortical gray matter (outer line) and the gray-white border (inner line) and highlight the contrast between less intense signal in the gray matter and more intense signal in the white matter. The arrows illustrate the following points: A. White matter tracts can be delineated from the frontal lobe to parietal lobe. B. White matter tracts are clearly identified throughout the occipital / temporal area. C. Scalloped appearance is seen with “fingers” of white matter in the frontal cortex. D. Low levels of signal in scalp or skull are distinguished from gray matter signal by the shape and position.

Figure 3: Typical Positive Scan: The upper (top) and lower (bottom) transverse slices show loss of gray-white matter contrast in multiple brain regions. The dotted lines illustrate the edge of the cortical gray matter. Compared to the images from the negative case in Figure 2, the gray matter signal is similar to white matter signal and the gray-white matter border is more difficult to discern. The arrows show the following points: A. White matter tracts are difficult to fully identify as they travel from frontal to parietal lobe. B. Borders of white matter tracts in occipital / temporal area are lost in places. C. Gray matter in medial parietal cortex (precuneus) has increased signal. D. Low levels of signal in scalp or skull are distinguished from gray matter signal by the shape and position.

​Quantitative Analysis

​Quantification of amyloid beta neuritic plaque levels (e.g., Centiloid scale or standardized uptake value ratio (SUVR)) can be used in conjunction with visual assessment and performed with FDA-authorized software indicated for quantification of brain amyloid beta PET scans. Refer to the drug manufacturer's training materials for qualitative and quantitative assessment and software manufacturers' documentation for software operation.