Florbetapir-PET to diagnose cerebral amyloid angiopathy: A prospective study.
OBJECTIVE
We hypothesized that florbetapir, a Food and Drug Administration-approved PET tracer, could distinguish cerebral amyloid angiopathy (CAA)-related intracerebral hemorrhage (ICH) from hypertensive ICH (HTN-ICH).


METHODS
We prospectively enrolled survivors of primary ICH related to probable CAA (per Boston Criteria, n = 10) and HTN-ICH (n = 9) without dementia. All patients underwent florbetapir-PET and multimodal MRI, and patients with CAA had additional Pittsburgh compound B (PiB) PET. Amyloid burden was assessed quantitatively (standard uptake value ratio [SUVR]) and visually classified as positive or negative.


RESULTS
The CAA and HTN-ICH groups had similar age (66.9 vs 67.1), sex, and leukoaraiosis volumes (31 vs 30 mL, all p > 0.8). Florbetapir uptake and PiB retention strongly correlated in patients with CAA both globally within cerebral cortex (r = 0.96, p < 0.001) and regionally in lobar cortices (all r > 0.8, all p ≤ 0.01). Mean global cortical florbetapir uptake was substantially higher in CAA than HTN-ICH (SUVR: 1.41 ± 0.17 vs 1.15 ± 0.08, p = 0.001), as was mean occipital SUVR (1.44 ± 0.12 vs 1.17 ± 0.08, p < 0.001), even after correcting for global SUVR (p = 0.03). Visual rating for positive/negative florbetapir demonstrated perfect interrater agreement (k = 1) and was positive for all 10 patients with CAA vs 1 of 9 HTN-ICH patients (sensitivity 100%, specificity 89%).


CONCLUSIONS
Florbetapir appears to label vascular amyloid in patients with CAA-related ICH. The approved florbetapir binary visual reading method can have diagnostic value in appropriate clinical settings.


METHODS
This study provides Class II evidence that florbetapir-PET provides a sensitivity of 100% (95% confidence interval [CI] 66%-100%) and specificity of 89% (95% CI 51%-99%) for determination of probable CAA among cognitively normal patients.
From the Hemorrhagic Stroke Research Center, Department of Neurology (M.E.G., P.F., G.R., K.S., S.M.G.), and Division of Nuclear Medicine and Molecular Imaging (J.A.B., K.A.J.), Massachusetts General Hospital, Harvard Medical School, Boston. edip@mail.harvard.edu.
M Edip
ME
Gurol
From the Hemorrhagic Stroke Research Center, Department of Neurology (M.E.G., P.F., G.R., K.S., S.M.G.), and Division of Nuclear Medicine and Molecular Imaging (J.A.B., K.A.J.), Massachusetts General Hospital, Harvard Medical School, Boston.
J Alex
JA
Becker
From the Hemorrhagic Stroke Research Center, Department of Neurology (M.E.G., P.F., G.R., K.S., S.M.G.), and Division of Nuclear Medicine and Molecular Imaging (J.A.B., K.A.J.), Massachusetts General Hospital, Harvard Medical School, Boston.
Panagiotis
P
Fotiadis
From the Hemorrhagic Stroke Research Center, Department of Neurology (M.E.G., P.F., G.R., K.S., S.M.G.), and Division of Nuclear Medicine and Molecular Imaging (J.A.B., K.A.J.), Massachusetts General Hospital, Harvard Medical School, Boston.
Grace
G
Riley
From the Hemorrhagic Stroke Research Center, Department of Neurology (M.E.G., P.F., G.R., K.S., S.M.G.), and Division of Nuclear Medicine and Molecular Imaging (J.A.B., K.A.J.), Massachusetts General Hospital, Harvard Medical School, Boston.
Kristin
K
Schwab
From the Hemorrhagic Stroke Research Center, Department of Neurology (M.E.G., P.F., G.R., K.S., S.M.G.), and Division of Nuclear Medicine and Molecular Imaging (J.A.B., K.A.J.), Massachusetts General Hospital, Harvard Medical School, Boston.
Keith A
KA
Johnson
From the Hemorrhagic Stroke Research Center, Department of Neurology (M.E.G., P.F., G.R., K.S., S.M.G.), and Division of Nuclear Medicine and Molecular Imaging (J.A.B., K.A.J.), Massachusetts General Hospital, Harvard Medical School, Boston.
Steven M
SM
Greenberg
D000368:Aged; D000814:Aniline Compounds / Q000378:metabolism; D016657:Cerebral Amyloid Angiopathy / Q000000981:diagnostic imaging*; D015331:Cohort Studies; D005026:Ethylene Glycols / Q000378:metabolism; D005260:Female; D005462:Fluorine Radioisotopes / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D013844:Thiazoles
C475519:2-(4'-(methylamino)phenyl)-6-hydroxybenzothiazole; D000814:Aniline Compounds; D005026:Ethylene Glycols; D005462:Fluorine Radioisotopes; D013844:Thiazoles; C545186:florbetapir