Objective To investigate the value of permeability surface (PS) in predicting hemorrhagic transformation (HT) in acute ischernic stroke (AIS) using CT peffusion (CTP).Methods The study included 31 consecutive patients who presented symptoms suggestive of an AIS for 3-9 h. All patients underwent CT examination (noncontrast CT,CTP).HT was determined by follow-up CT images.According to presence of HT,the AIS was divided into HT group (PSHT,11 patients) and non-HT group(PSNo-HT,20 patients).PS,cerebral blood flow (CBF),cerebral blood volume (CBV) and mean transit time (MTT) on both sides of brains were measured.The relative PS(rPS),relative CBF (rCBF),relative CBV(rCBV) and relative MTT(rMTT) were obtained by calculating the ratio of the values of bilateral regions.The rPS between PSHT and PSNo-HT was compared with an exact Wilcoxon signed-rank test. The rCBF,rCBV,rMTT and the PS of the ischemic side between PSHr and PSNo-HT were compared with independent-sample t test.Meanwhile,Spearman rank correlation analysis was conducted to analyze the relationship between the CTP parameters and HT.ResultsThe PS value of ischemic side was (1.61±0.77) ml · min - 1 · 100 g-1 for the PSHT group,and the value was (0.91 ± 0.49) ml · min - 1 · 100 g- 1 for the PSNo-HT group.For the PSHT group,rPS,rCBF,rCBV,rMTT were 2.76 ±0.78,0.32 ±0.18,0.66 ±0.31,2.67 ±0.71,and for the PSNo-HT group,rPS,rCBF,rCBV,rMTT were 1.35 ±0.19,0.50±0.21,0.91 ±0.28,2.62 ± 1.31.Compared with PSNo-HT,PSHT had higher rPS and PS value,and there were significant statistical differences (U =0.000,t =3.070,P ＜0.01).But rCBF and rCBV values were lower in the PSHT group compared to the PSNo-HT group,and there were significant statistical differences (trCsF =2.343,trCBV =2.210,P ＜ 0.05).There was no significant statistical difference in rMTT between the two groups(t =0.118,P ＞ 0.05).Significant positive correlations were detected between the rPS and PS with HT(r=0.496,0.821,P ＜0.01).ConclusionsThe value of rPS is helpful in predicting HT in AIS.And it can be used as a predictor in determining clinical personalized treatment and thus reduce the incidence of adverse events.

Objective To explore the CT and MRI characteristics of hepatic epithelioid angiomyolipomas (H EA)in order to improve recognition and diagnostic accuracy of the disease.Methods The CT and MR imaging data of 8 patients with HEA proved by pathology were analyzed retrospectively.Among these patients,4 cases underwent plain and enhanced CT scans,2 plain and enhanced MRI scans and 2 both CT and MRI scans.Results In the 8 cases,7 were female.All lesions were solitary and well-defined,with maximum diameters ranging from 42 mm to 68 mm.6 leions on plain CT displayed slightly low density,of which 1 showed fat density and other 2 showed patchy cystic areas.MRI showed 4 masses with slight hypointensity on T1 WI,slight hyperintensity or hyperintensity on T2 WI,of which one demonstrated decreased signal on out-phase of T1 WI.On enhanced MR images,7 masses were significantly inhomogeneous in arterial phase,5 showed "fast wash-in and slow wash-out",2 "fast wash-in and wash-out"and 1 "slow wash-in and wash-out".6 showed"central vascular sign"in arterial phase and 2 displayed incomplete pseudocapsule in the portal venous and delayed phases.Conclusion Inhomogeneous enhancement in arterial phase,central vascular sign,fast wash-in and slow wash-out enhancement and no pseudocapsule are imaging features of HEA,which can help to improve the diagnostic accuracy.Its diagnosis still depends on histopathology and immunohistochemistry.