Preliminary Clinical Study Of LDCTP And ULDCTP Combined With IMR In The Diagnosis Of Cerebral Stroke

Part one.Assessing the image quality of low-dose CT cerebral perfusion imaging combined with IMRObjective To investigate the feasibility of low-dose CT examination combined with IMR in cerebral CT perfusion(CTP)imaging.Materials and Methods Patients with clinical suspicion of cerebral infarction underwent the cerebral CTP imaging were enrolled in this study.60 patients who had normal CTP imaging in one of cerebral hemispheres were divided into group A(30 cases,80Kv-150 m As with FBP reconstruction)and group B(30 cases,80Kv-30 m As with FBP,i Dose44,IMR1,IMR2,IMR3 reconstruntion respectively).At the level of the most superior margin of the ganglionic structures(ASPECTS 2),quantitative and qualitative analysis of CTP images was performed by one radiologist.And CTDIvol,DLP was recorded and effective dose(ED)was calculated.CT and SD values,SNR,CNR,perfusion parameters(CBV,CBF,MTT,TTP),subjective CTP imaging scores were compared among 6 reconstruction sets using ANOVA or Kruskal Wallis test.Results(1).CT and SD values at grey matter(GM)and white matter(WM)were significantly higher and the SNR,CNR were significantly lower between group A and group B reconstructed with FBP and i Dose44(P<0.05).All of subjective CTP imaging scores with FBP and i Dose44 were 0 in group B.(2).There was no statistical significance in CT and SD values,SNR,CNR,and subjective CTP imaging scores between group A and group B reconstructed with IMR1(P>0.05).The CT values of GM,SD values of GM and WM were significantly lower,SNR,CNR of of the GM and WM were significantly higher between group A and group B reconstructed with IMR2,IMR3(P<0.05).(3).There was no statistical significance in the perfusion parameters at ROIs of GM and WM between group A and group B reconstructed with i Dose44,IMR1,IMR2,IMR3 and group A(P>0.05).(4).The ED in group B was 0.50 m Sv,decreased by 80% compared to ED in group A which was 2.52 m Sv.Conclusion There are stable perfusion parameters,stable imaging quality and lower radiation dose using LDCTP(80Kv-30 m As)examination combined with IMR.It is considerd that LDCTP could become a routine cerebral CTP method.Part two.Preliminary clinical study of ULDCTP combined with IMR in the diagnosis of cerebral strokeObjective To investigate the clinical application of ultra-low-dose CT Perfusion(ULDCTP)examination combined with IMR in the diagnosis of cerebral stroke.Materials and Methods 95 patients with clinical suspicion of ischemic stroke who underwent the cerebral CT perfusion imaging and MRI within 3 days were enrolled in this study.These patients were divided into group A(45 cases,80Kv-30 m As with IMR2 reconstruction)and group B(50 cases,80Kv-10 m As with IMR2 reconstruction).The relative normal perfusion imaging at ASPECT2 level were chosen for quantitative and qualitative analysis.CTDIvol,DLP was recorded and effective dose(ED)was calculated in each case.CT and SD values,SNR,CNR,perfusion parameters(CBV,CBF,MTT and TTP),subjective CTP imaging scores were compared respectively between two groups by using Independent-Samples T test or Mann-Whitney U test depending on the homogeneity of variance.The detection rate of different size of cerebral infarcts on CTP imaging was also compared in two groups.Results(1).Subjective CTP imaging scores in group A and group B was were high and moderate and the Kappa were 0.70 and 0.51 respectively.(2).There was no statistical significance in CT values of GM and WM between two groups(P>0.05).SD values in group B were larger than those in group A(P<0.05).SNR and CNR in group B was smaller than that in group A(P<0.05).(3).There was no statistical significance in the CBV of the GM and WM,MTT of the GM and TTP of the GM and WM between two groups(P>0.05).There was statistical significance in the CBF of GM and WM and MTT of WM between two groups(P<0.05).(4).The detection rate of lacunars,focal and massive ischemic cerebral infarctions in group A was 4.44%,100%,100%,those in group B was 4.00%,100%,100%,respectively.(5).The ED in group A and group B was 0.50 m Sv,0.17 m Sv.(6)."Concentric circles" and "black holes" artifacts at CTP images were seen obviously in group B.Conclusion The characteristics of ULDCTP using 80Kv-10 m As with IMR were ultralow radiation,fair CTP imaging quality,and more imaging artifacts,et al.But focal and massive cerebral infarction could be diagnosed based on ULDCTP imaging.