## 3 Experimental Results  
### Material and Procedure  
A dataset of 72 subjects of middle age (age: 35:62 years) was used in this study. The dataset includes an MRA scan and blood pressure measurements for each subject. The dataset was acquired and approved by the Institutional Review Board (IRB) at the university of Pittsburgh with accordance to relevant regulations and guidelines. Initial screening via phone calls was made with each participant to ensure eligibility. All participants provided informed consent before any study procedures. Participants were enrolled in the study with the following exclusion criteria: (1) general medical conditions: ischemic coronary artery disease, pregnancy, chronic liver disease, cancer (treatment < 12 months), diabetes mellitus (fasting blood glucose > 125 mg/dL), or chronic kidney disease (creatinine > 1.2 mg/dL); (2) neuropsychiatric conditions: multiple sclerosis, stroke, epilepsy, serious head injury, brain tumor, and major mental illness; (3) using prescription medications for hypertension \begin{table}
\begin{tabular}{p{42.7 pt} p{42.7 pt} p{42.7 pt} p{42.7 pt} p{42.7 pt} p{42.7 pt} p{42.7 pt}} \hline \hline
**Classifiers** & **Kernel** & **Features** & **Validation-Scenario** & **Whole Brain Accuracy \%** & **Anterior Accuracy \%** & **Posterior Accuracy \%** \\ \hline \multirow{3}{*}{Ensemble} & \multirow{3}{*}{Bagged Trees} & Median of diameter change, median of tortuosity change, delta MAP, delta DBP & 5-fold & 75 & 72.2 & 69.4 \\ \cline{3-8}  & & & & & & \\ \hline \multirow{3}{*}{KNN} & \multirow{3}{*}{Weighted} & Average of diameter change, Average of tortuosity change, delta MAP, delta DBP & \multirow{3}{*}{10-fold delta MAP, delta SBP, delta DBP} & \multirow{3}{*}{77.8} & \multirow{3}{*}{77.8} & \multirow{3}{*}{66.4} \\ \cline{3-8}  & & & & & & \\ \cline{3-8}  & & & & & & \\ \hline \multirow{3}{*}{KNN} & \multirow{3}{*}{Fine} & Diameter change, tortuosity change, delta MAP, delta DBP & \multirow{3}{*}{25\% hold-out} & \multirow{3}{*}{88.9} & \multirow{3}{*}{55.6} & \multirow{3}{*}{83.3} \\ \cline{3-8}  & & & & & & \\ \hline \multirow{3}{*}{Ensemble} & Subspace KNN & Diameter change, tortuosity change, delta MAP, delta DBP & \multirow{3}{*}{25\% hold-out} & \multirow{3}{*}{88.9} & \multirow{3}{*}{55.6} & \multirow{3}{*}{83.3} \\ \cline{3-8}  & & & & & & \\ \hline \multirow{3}{*}{Ensemble} & Bagged Trees & Diameter change, tortuosity change, delta MAP, delta DBP & \multirow{3}{*}{15\% hold-out} & \multirow{3}{*}{90} & \multirow{3}{*}{90} & \multirow{3}{*}{70} \\ \cline{3-8}  & & & & & & \\ \hline \multirow{3}{*}{KNN} & \multirow{3}{*}{Weighted} & Diameter change, tortuosity change, delta SBP, delta DBP & \multirow{3}{*}{15\% hold-out} & \multirow{3}{*}{90} & \multirow{3}{*}{80} & \multirow{3}{*}{60} \\ \cline{3-8}  & & Diameter change, tortuosity change, delta MAP, delta SBP, delta DBP & \multirow{3}{*}{20\% hold-out} & \multirow{3}{*}{92.9} & \multirow{3}{*}{71.4} & \multirow{3}{*}{71.4} \\ \cline{3-8}  & & Diameter change, tortuosity change, delta MAP, delta DBP & \multirow{3}{*}{20\% hold-out} & \multirow{3}{*}{100} & \multirow{3}{*}{85.7} & \multirow{3}{*}{57.1} \\ \cline{3-8}  & & Diameter change, tortuosity change, delta MAP, delta DBP & \multirow{3}{*}{100} & \multirow{3}{*}{85.7} & \multirow{3}{*}{57.1} \\ \cline{3-8}  & & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Classification Accuracy based on the whole brain, anterior compartment, and posterior compartment. and psychotropic drugs. MRA scans were acquired using a 3T Trio TIM scanner with a 12-channel phased-array head coil. Each MRA scan is composed of about 160 slices with a thickness of 0.5 mm, a resolution of 384 \(\times\) 448, a flip angle of 15 degrees, a repetition time of 21 ms, and an echo time of 3.8 ms. MRA scans were acquired two times separated by approximately 700 days. Blood pressure measurements were gathered using the auscultatory technique with cuff size appropriate to patient arm after giving him/her a seated rest of 5-min two times over the 700 days too.