Donanemab — age59–86 years
Donanemab — MMSEMMSE 20–28
Lecanemab — age50–90 years
Lecanemab — MMSE/qualifiersMMSE ≥22; CDR global 0.5 or 1.0; CDR‑SB ≥0.5 and/or Memory Box ≥0.5
Dementia documentation before structural imagingEstablished dementia with documentation of 6 months cognitive decline (or appropriate neuro/bedside testing) required
Baseline MRI timing for amyloid therapiesBaseline MRI within 3 months prior to medication initiation (MRI 70551 or 70553) — amyloid PET (78811/78814) optional per pathway
MRI monitoring on donanemabMRI prior to 2nd, 3rd, 4th and 7th infusions; MRI for ARIA or neurologic symptoms; amyloid PET at 6,12,18 months
MRI monitoring on lecanemabMRI prior to 5th, 7th and 14th infusions; MRI for ARIA or neurologic symptoms; amyloid PET at 18 months
ARIA / neurologic symptom acute imagingIf neurologic signs/symptoms during therapy: CT head noncontrast (70450) OR MRI brain (70551/70553); follow-up MRI as indicated
Orbital metallic fragment screeningPlain x‑ray orbit films (2 views) generally sufficient; CT orbital rarely necessary; x‑ray detects ≥0.12 mm, CT ≥0.07 mm
CTA/MRA coding noteIf arterial and venous CT/MR performed same session, report single CTA/MRA CPT code; MRA/CTA head/neck codes listed for vascular evaluation