POTENTIAL FOR IMAGING CEREBRAL AMYLOID DEPOSITS USING I-123 LABELED SERUM AMYLOID-P COMPONENT AND SPET

The systemic and cerebral accumulation of I-123-labelled serum amyloid P component (I-123-SAP) was studied in patients with hereditary cereb ral amyloid angiopathy-Dutch type (HCHWA-D) to determine the usefulnes s of I-123-SAP imaging in cerebral amyloidosis. Whole-body and SPET sc intigraphic imaging was performed in two patients with HCHWA-D and fou r controls after the intraveous injection of I-123-SAP. Venous I-123-S AP clearance was also determined. Accumulation of the tracer was obser ved in the cerebral cortex of both patients, whereas no accumulation w as seen in the controls. Blood clearance of radioactivity was similar in the patients and controls, suggesting that the amount of uptake of I-123-SAP in the cerebral amyloid deposits is relatively small. We bel ieve this to be the first demonstration of cerebral amyloid deposits i n vivo. Our findings indicate that I-123-SAP scintigraphy has possibil ities for the diagnosis of patients with cerebral amyloid diseases, in addition to its use in patients with systemic amyloid deposition.