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Objective To establish a platform by using carotid MRI and computational fluid dynamics (CFD) to assess hemodynamic changes around carotid atherosclerotic plaques. Methods Thirteen patients with carotid atherosclerosis were recruited in this study. Six volunteers were regarded as normal controls. All the patients and volunteers underwent carotid MRI and contrast-enhanced magnetic resonance angiography (CEMRA). Carotid MRI was used to visualize the plaque structures and components. All plaques were divided into different types according to plaque components. CEMRA images were used to obtain three-dimensional (3D) models of carotid bifurcations, whose boundary conditions were specified using CFD front-end software, and then the mesh file of the 3D models were obtained to import to CFD software to visualize hemodynamic maps, including wall shear stress (WSS), static pressure and blood velocity. Results Fifteen diseased internal carotid arteries (ICAs) were assessed. According to the MRI appearance of the plaques, the types of these plaques were from IV-V to VIII. All of these were vulnerable plaques which caused irregular stenosis of ICAs. The WSS, static pressure and blood velocity were (79.86 ± 57.83) Pa, (- 7586.81 ± 9313.83) Pa, (2.76±1.81) m/s, respectively in the diseased ICAs group and (2.52 ± 0.58) Pa, (- 71.65 ± 30.89) Pa, (0.21 ± 0.06) m/s, respectively in the normal control group. In the diseased ICAs group WSS was elevated heterogenously and static pressure was decreased heterogenously near the plaques. The blood velocity near the plaques was increased but still streamlined. Statistical significant differences were shown for WSS, static pressure and blood velocity between 2 groups (P = 0.000, for all). Conclusions The platform combining MRI and CFD can be used to analyze the plaque structures and fluid dynamic change near the plaques, suggesting hemodynamics plays an important role in the plaque progression and vulnerability. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the association between dynamic progressive enhancing foci ('dynamic spot sign') in acute haematoma on CT perfusion source images (CTP-SI) and haematoma expansion. Methods: One hundred twelve consecutive patients with spontaneous intracerebral haemorrhage according to unenhanced CT, CTP and CT angiography within 6 h of symptom onset were prospectively evaluated. Patients were dichotomised according to the presence/absence of the dynamic spot sign on CTP-SI in haematoma. The predictive value of haematoma expansion was analysed. Results: Haematoma expansion was detected in 28 patients (25.0 %) on follow-up unenhanced CT images. Thirty patients (26.8 %) demonstrated the dynamic spot sign on CTP-SI, about 83.3 % of patients with haematoma expansion ( P < 0.001). Sensitivity, specificity, positive predictive value, negative predictive value and kappa value for expansion were 89.3 %, 94.0 %, 96.3 %, 83.3 % and 0.814, respectively. In multiple regression, the presence of the CTP dynamic spot sign within acute haematomas independently predicted haematoma expansion; the univariate analysis OR value was 131.667 (29.386-590.289), P < 0.0001. Moreover, the multivariate analysis CTP dynamic spot sign OR value was 203.996 (32.123-1295.488), P < 0.0001. Conclusions: The CTP-SI dynamic spot sign is associated with acute haematoma expansion, is more direct in showing active ongoing bleeding and has a higher predictive value than the CTA spot sign. Key Points: • It is important to identify potential progression of spontaneous intracerebral haemorrhage. • Dynamic enhancement within CT perfusion source images is associated with haemorrhage expansion. • The CTP dynamic spot sign may be present throughout arterial to venous phase imaging. • The CTP dynamic spot sign carries a higher predive value for haematoma expansion than CTA. [ABSTRACT FROM AUTHOR]

Computed tomography perfusion (CTP) map can sensitively and accurately distinguish between infarct core and ischemic penumbra. However, CTP mapping software might not generate a perfusion map because of head movement; thus, analysing CTP source images (CTP-SI) is necessary in this situation to provide information for stroke diagnosis and therapy. In our work, 'one-stop shop' computed tomography (CT) examination including non-contrast-enhanced CT (NCCT), CTP, CT angiography (CTA) were performed in 24 patients with symptoms of acute stroke less than 9 hours. We divided patients into two groups (with and without delayed perfusion on CTP-SI), and compared the Alberta Stroke Program Early CT Score (ASPECTS) on CTP-SI and CTA-SI with follow-up imaging. Using follow-up imaging ASPECTS as the final infarct size, our results suggests that the ASPECTS of both CTP-SI and CTA-SI effectively predict final infarct core in the group without delayed perfusion, whereas CTP-SI has a potential advantage over CTA-SI in being able to predict final infarct core in the group with delayed perfusion. In conclusion, CTP-SI provides useful complementary information when CTP map software could not generate perfusion maps. [ABSTRACT FROM AUTHOR]