# Positron Emission Tomography in Cerebral Amyloid Angiopathy: A Scoping Review
## 3 Results
### CAA-Related ICH and SAH  
Studies consistently demonstrate that patients with probable CAA exhibit elevated amyloid uptake on PET imaging, particularly in the occipital regions. For example, [PERSON] et al. [27] highlighted a 40% higher occipital standardized uptake value ratio (SUVR) in probable CAA compared to AD, underscoring the regional specificity of amyloid deposition in CAA. Conversely, [PERSON] et al. [28] reported an occipital-to-global SUVR of 1.8 \(\pm\) 0.3, significantly higher than in AD patients (\(p\) < 0.001).  
Probable CAA patients with ICH consistently show higher regional amyloid burdens. Amyloid PET findings predicted ICH recurrence with 85% sensitivity and 82% specificity, indicating its prognostic utility [29]. Similarly, a significant association was found between recurrent ICH and elevated global SUVR (1.7 \(\pm\) 0.3, \(p\) = 0.02) [30].  
Amyloid PET has proven effective in distinguishing probable CAA from mimicking conditions like hypertensive ICH, with an area under the curve (AUC) of 0.87 for amyloid PET in differentiating CAA from hypertensive ICH [31]. These findings support amyloid PET as a valuable diagnostic adjunct when traditional imaging is inconclusive.  
The Boston criteria for CAA diagnosis [5,18] are further refined by amyloid PET, particularly for probable cases with lobar ICH. In fact, one study found that 73% of probable CAA cases demonstrated occipital-dominant amyloid deposition, significantly higher than in AD patients (\(p\) < 0.001) [32]. This regional specificity helps to differentiate CAA from other amyloidosis and guides patient management.  
Amyloid PET findings correlate with the distribution and burden of cerebral microbe-leeds in probable CAA, with a strong correlation (r = 0.62, \(p\) < 0.001) between occipital amyloid deposition and lobar microbe-leeds [33], and a higher amyloid SUVR in recurrent ICH cases [34].  
Amyloid PET enhances the sensitivity of CAA diagnosis and helps to stratify patients based on ICH risk. For example, [PERSON] et al. [35] reported an 87% sensitivity and 78% specificity for diagnosing probable CAA in ICH patients.  
The main findings of the selected studies are summarized in Table 3.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Reference** & **Population** & **Details** & **Findings** & **Comments** \\ \hline \multirow{6}{*}{
\begin{tabular}{} \end{tabular} } & & Probable CAA was defined by & - Occipital lobe amyloid & \multirow{6}{*}{- The findings establish the occipital amyloid burden as a hallmark of CAA.} \\  & & Boston criteria [18], and confirmed by imaging findings (including MRI and [11]C]PIB PET). & & - Occipital lobe amyloid & \multirow{6}{*}{- The findings establish the occipital amyloid burden as a hallmark of CAA.} \\  & & and & AD patients were included to & & - The findings suggest that regional \\  & & AD: 75 & investigate differences in amyloid & - Regional amyloid & \multirow{6}{*}{- The findings establish the occipital amyloid burden as a hallmark of CAA.} \\  & & HC: 20 & regionality, particularly occipital involvement. & & - Regional amyloid patterns can predict \\  & & HCs were used to analyze regional & - patterns correlated with clinical manifestations & \multirow{6}{*}{- The findings establish the occipital amyloid burden as a hallmark of CAA.} \\  & & amyloid patterns compared to CAA patients. & & - Regional amyloid patterns can predict \\ \hline \hline \end{tabular}
\end{table}
Table 2: _Cont._