| Part Ⅰ Quantitative evaluation of acute pancreatitis based on dual-energy CT Purpose: Dual-source dual-energy CT was used to evaluate the parameters of dual-energy CT(DECT)for quantitative diagnosis of acute pancreatitis(AP)and its application value in severity classification.Methods: A total of 60 AP patients(38 males and 22 females)who were treated in our hospital in the past two years and met the inclusion and exclusion criteria were collected.The mean age was 47.43±13.47.According to the CT severity index,the patients were divided into two groups: group A(26 patients in the mild AP group)and group B(34 patients in the moderate and severe AP groups).All patients underwent plain scan and three enhancement scan using dual-energy mode of dual-source CT(A/B bulb tube voltage is 100 kV/sn150 kV).Iodine concentration,fat fraction and slope of spectral HU curve of three enhancement scan(arterial phase,venous phase and delayed phase)of AP in the two groups were measured,and the difference of each parameter value between the two groups was compared.For all DECT parameters,the receiver operator characteristic curve(ROC)was used to evaluate the differential diagnosis efficiency of AP in the two groups.Spearman level correlation analysis is used to evaluate the correlation between DECT parameters and AP severity CTSI score.P<0.05 was considered statistically significant.Results:1.DECT parameter values and their differences between the two groups: The intravenous iodine concentration was 2.54±0.34mg/ml in group A and 2.16±0.37mg/ml in group B.The arterial iodine concentration was 2.76±0.67mg/ml in group A and 2.18±0.49mg/ml in group B.The slope of Spectral HU Curve of the venous period was 4.61±0.60 in group A and 3.80±0.62 in group B.The slope of Spectral HU Curve of arterial e period was 5.05±1.28 in group A and 3.83±0.99 in group B.The values of the above four parameters were higher in group A than in group B(P<0.001).2.ROC display: Iodine concentration in venous phase,iodine concentration in arterial phase,slope of spectral HU curve in venous phase,and slope of spectral HU curve in arterial phase were good for differentiating AP between the two groups.The area under curve is 0.799,0.753,0.842 and 0.774,respectively.The best discriminant efficiency is the slope of spectral HU curve of the venous period.3.The values of the above four DECT parameters in AP patients decreased with the increase of CT severity index score,showing a negative correlation,and the r value was between-0.492 and-0.569(P<0.001).Conclusion: This research shows that: Dual energy CT imaging can quantitatively analyze acute pancreatitis by DECT parameters.The obtained iodine concentration and slope of spectral HU curve can be used to distinguish mild and severe acute pancreatitis,and have a good correlation.It can supplement the functional information on the basis of CT morphology for the severity and prognosis of the disease,which has good clinical application value.Part Ⅱ Quantitative evaluation of acute pancreatitis based on Intravoxel incoherent motion imagingPurpose: Intravoxel incoherent motion of diffusion-weighted imaging(IVIM-DWI)was used to evaluate the value of IVIM-DWI parameters in the quantitative diagnosis of acute pancreatitis(AP)and its application in severity classification.Methods: A total of 28 AP patients(18 males and 10 females)who were admitted to our hospital for treatment in the past two years and met the inclusion and exclusion criteria were collected.The average age was 44.36±12.90.According to the MR severity index,the patients were divided into two groups: group a(14 patients with mild AP)and group b(14 patients with moderate severe AP and severe AP).All patients were scanned with IVIM-DWI sequence using 1.5T magnetic resonance imaging.The f value,D value and D* value of the two groups were measured,and the differences of these three parameters between the two groups of AP were compared,and All parameters were analyzed by ROC for their differential diagnosis efficacy in the two groups of AP.Spearman rank correlation analysis was used to evaluate the correlation between IVIM-DWI parameters and MR severity index of acute pancreatitis.P<0.05 was considered statistically significant.Results:1.The f value of group a was 21.36±7.85%,which was significantly higher than that of group b(14.24±4.22%)(P<0.05).There was no significant difference in D value and D* value between group a and group b(P>0.05).2.The f value was good for the evaluation of differentiating the two groups(mild and severe)of acute pancreatitis,and the AUC was 0.852.D values and D* values were less effective in differentiating severe from mild acute pancreatitis.3.f value was negatively correlated with MR severity index of acute pancreatitis(r =-0.713,P=0.0003).Conclusion: This research shows that:Among all parameters of IVIM-DWI,the perfusion related f value can better distinguish mild and severe acute pancreatitis,and is negatively correlated with the severity of acute pancreatitis.This study supplemented functional information on the basis of MR morphology,which has certain clinical application value. |
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