Fig 5. Comparison of image quality between MP-CTA and SP-CTA. A single section of MP-CTA (A), SP-CTA (B), and MIP reconstruction of MP-CTA (C) and SP-CTA (D) is demonstrated. The MP-CTA images were acquired 10–15 minutes after the SP-CTA; therefore, we could find images at almost the same level for comparison. The phase of maximal arterial enhancement of MP-CTA was selected. Higher attenuation of the vascular opacification is easily appreciated in the MP-CTA. Note that venous contamination in the SP-CTA is greater than that in the MP-CTA, which is more obvious in MIP images; and it may interfere with the differentiation of the arteries and veins. The occlusion of right MCA can be detected in both methods. The MP-CTA is noisier, and the contour of the vessels appears coarser than that in SP-CTA. All images were presented with the same window setting (window/level = 1000/100).