PET imaging for the evaluation of cerebral amyloid angiopathy: a systematic review

Abstract

Purpose In the last years, the role of PET imaging in the assessment of cerebral amyloid angiopathy (CAA) is emerging. In this setting, some tracers have proven their utility for the evaluation of the disease (mainly 11C-Pittsburgh compound B [11C-PIB]), however, the value of other radiotracers has to be clarified. The aim of this systematic review is, therefore, to assess the role of PET imaging in the evaluation of CAA. Methods A wide literature search of the PubMed/MEDLINE, Scopus, Embase, Web of Science and Cochrane library databases was made to find relevant published articles about the diagnostic performance of PET imaging for the evaluation of CAA. Quality assessment including the risk of bias and applicability concerns was carried out using QUADAS-2 evaluation. Results The comprehensive computer literature search revealed 651 articles. On reviewing the titles and abstracts, 622 articles were excluded because the reported data were not within the field of interest. Twenty-nine studies were included in the review. In general, PET imaging with amyloid tracers revealed its value for the assessment of CAA, for its differential diagnosis and a correlation with some clinico-pathological features. With less evidence, a role for 18F-fluorodeoxiglucose (18F-FDG) and tau tracers is starting to emerge. Conclusion PET imaging demonstrated its utility for the assessment of CAA. In particular, amiloid tracers revealed higher retention in CAA patients, correlation with cerebral bleed, the ability to differentiate between CAA and other related conditions (such as Alzheimer's disease) and a correlation with some cerebrospinal fluid biomarkers.

The Association Between Positive Amyloid-PET and Cognitive Decline Is Not Always Supportive of Alzheimer’s Disease: Suggestions from a Case Report

“…In this regard, an author compared the occipital/whole cortex uptake between AD and sporadic CAA cases in “late phase amyloid imaging” (using PIB as tracer and SUVR, pons as reference tissue), detecting a significantly higher occipital/whole cortex ratio in CAA than in AD cases [ 25 ].These findings have been confirmed later by other authors using again PIB as tracer and cerebellar cortex as the reference region [ 26 ], whereas Planton found only a trend for an increased occipital/global ratio in CAA-ICH patients compared to MCI-AD using Florbetapir as tracer and cerebellar cortex as the reference region [ 27 ]. The use of Amy-PET in the diagnostic of CAA is also supported by recent reviews on this topic [ 22, 28 ].…”

“…Given the high sensitivity of FDG-PET to recognize AD [ 21 ], we used this visual finding to question a diagnosis of AD. Indeed, recent reports suggest the potential of FDG-PET itself to differentiate between CAA and AD [ 13 ], even if with lower strength compared to Amy-PET [ 22 ]. Nowadays a formal diagnosis of CAA is not accepted unless a brain biopsy is performed, making it hard to obtain an in vivo formal diagnosis.…”