Predicting sites of new hemorrhage with amyloid imaging in cerebral amyloid angiopathy.
OBJECTIVE
We aimed to determine whether amyloid imaging can help predict the location and number of future hemorrhages in cerebral amyloid angiopathy (CAA).


METHODS
We performed a longitudinal cohort study of 11 patients with CAA without dementia who underwent serial brain MRIs after baseline amyloid imaging with Pittsburgh compound B (PiB). Mean distribution volume ratio (DVR) of PiB was determined at the sites of new micro/macrobleeds identified on follow-up MRI and compared with PiB retention at "simulated" hemorrhages, randomly placed in the same subjects using a probability distribution map of CAA-hemorrhage location. Mean PiB retention at the sites of observed new bleeds was also compared to that in shells concentrically surrounding the bleeds. Finally the association between number of incident bleeds and 3 regional amyloid measures were obtained.


RESULTS
Nine of 11 subjects had at least one new microbleed on follow-up MRI (median 4, interquartile range [IQR] 1-9) and 2 had 5 new intracerebral hemorrhages. Mean DVR was greater at the sites of incident bleeds (1.34, 95% confidence interval [CI] 1.23-1.46) than simulated lesions (1.14, 95% CI 1.07-1.22, p < 0.0001) in multivariable models. PiB retention decreased with increasing distance from sites of observed bleeds (p < 0.0001). Mean DVR in a superior frontal/parasagittal region of interest correlated independently with number of future hemorrhages after adjustment for relevant covariates (p = 0.003).


CONCLUSIONS
Our results provide direct evidence that new CAA-related hemorrhages occur preferentially at sites of increased amyloid deposition and suggest that PiB-PET imaging may be a useful tool in prediction of incident hemorrhages in patients with CAA.
Departmentsof Neurology, Massachusetts General Hospital, Boston, USA. egurol@yahoo.com
M Edip
ME
Gurol
Gregory
G
Dierksen
Rebecca
R
Betensky
Christopher
C
Gidicsin
Amy
A
Halpin
Alex
A
Becker
Jeremy
J
Carmasin
Alison
A
Ayres
Kristin
K
Schwab
Anand
A
Viswanathan
David
D
Salat
Jonathan
J
Rosand
Keith A
KA
Johnson
Steven M
SM
Greenberg
D000368:Aged; D000369:Aged, 80 and over; D000682:Amyloid / Q000378:metabolism*; D001921:Brain / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology*; D001931:Brain Mapping; D016657:Cerebral Amyloid Angiopathy / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D020300:Intracranial Hemorrhages / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011877:Radionuclide Imaging
D000682:Amyloid