Diffusion weighted imaging for quantification of liver fibrosis in patients using normalized apparent diffusion coefficient values at 3.0 T MR / 中华放射学杂志

ObjectiveThe purpose of this study is to discuss the diagnostic accuracy of nornalized liver ADC using the spleen and renal cortex as reference organs for the diagnosis of liver fibrosis.Methods Forty three patients with liver disease (chronic liver disease group) at compensated stage and 10 healthy volunteers (control group) were retrospectively assessed with diffusion-weighted imaging at a 3.0 T MR unit.Liver ADC,spleen ADC,renal ADC and normalized ADC (defined as the ratio of liver ADC to spleen ADC or renal cortex ADC,S-ADC and R-ADC for short) were measured in patients stratified by fibrosis stage.Spearman analysis was used to see the correlation between fibrosis stages and ADC,one-way ANOVA was used to compare the ADCs in different fibrosis stages.Logistic regression analysis was used to determine the performance of ADC for prediction of liver fibrosis,and show the area under the curve ( AUC),sensitivity and specificity choosing the optimal cutoff value that maximized the Youden index.ResultsTen volunteers belonged to SO stage.From SO to S4 stage,there were 2,5,9,12 and 15 patients,correspondingly,liver ADCwere (1.37±0.13) ×10-3,(1.33±0.16) ×10 -3,(1.17±0.16) ×10-3,(1.23±0.14) ×10-3and ( 1.12 ±0.11 ) × 10-3mm2/s,S-ADC were 1.86 ±0.18,1.68 ±0.12,1.34 ±0.14,1.48 ±0.15 and 1.34±0.10,R-ADC were 0.71 ±0.08,0.68 ±0.12,0.61 ±0.09,0.64 ±0.11 and 0.60 ±0.08respectively,and the differences among them were significant ( F =6.48,18.70 and 3.04,P ＜0.05 ).The correlation between fibrosis stage and S-ADC was stronger than between fibrosis stage and liver ADC,R-ADC (r =- 0.71,- 0.51,- 0.41 ;P ＜ 0.01 ).S-ADC was superior to liver ADC and R-ADC for detection of S2,S3 and S4 fibrosis stage (Youden index:0.91,0.58,and 0.59).ConclusionSpleen normalized liver ADC improves diagnostic accuracy for detection of liver fibrosis than liver ADC and renal normalized liver ADC.

Optimal window width and center level settings in 256-slice spiral CT diagnosis of costal cartilage fracture / 中国医学影像技术

Objective To investigate the optimal window level and center level settings in the diagnosis of costal cartilage fracture with 256-slice spiral CT through ROC analysis. Methods Thirty patients with suspected costal cartilage fractures underwent 256-slices chest spirals CT scaning. CT value of costal cartilage was measured by three experienced radiologists. The soft copy images of three kinds of window level and window width (-100 HU/1120 HU, 100 HU/1120 HU, 300 HU/1120 HU) were analyzed independently in PACS with dual-blind method, and the diagnosis results were taken ROC analysis with SPSS 16.0 software. The diagnostic accuracy of three physicians were evaluated and compared according to the area under the ROC curve (Az). Results A total of 8 patients of costal cartilage fractures were confirmed by CT diagnosis combined with clinical follow-up. The mean CT value of 30 patients was (98.78±32.86) HU. The area under the ROC curve with the window level and center level settings of (100 HU/1120 HU) were bigger than that of other window level and window width (P=0.045,P=0.002). Kappa identity test showed that there was a powerful conformability between the diagnostic results of three physicians. Conclusion 256-slice spiral CT is a good way for the diagnosis of costal cartilage fractures with suitable window level and center level settings.

CT manifestations of patients with swine-origin influenza A H1N1 QI / 中华放射学杂志

Objective To explore the manifestations of chest multi-slice spiral CT in patients with initial infection of swine-origin influenza A (H1N1) virus (S-OIV). Methods The chest multi-slices spirals CT images of 19 firstly diagnosed patients with swine-origin influenza A (H1N1) in our institution were retrospectively studied. CT manifestations were evaluated by three experienced radiologists. Location, appearance of lung abnormalities, abnormal distribution, pleural effusion and others (pericadiaum, lymphadenopathy and pleural thickening) were observed and quantitatively analyzed. The correlation of ground-glass and consolidation CT scores with the fever time was studied. Results The abnormal CT findings were observed bilaterally in 18 of 19 subjects including ground-glass (n= 3), consolidation (n=3 ), consolidation accompanied with ground-glass (n=12). Most of these lesions were distributed diffusively (n=14) while the others located in the middle and low lobes (n= 4). Unilateral (n=3) or bilateral (n=2) pleural effusion were observed. Lymphadenopathy (n=2), effusion of pericadium (n=1), pleural thickening (n=1) and cardiac enlargement (n=2) were also found in patients with H1N1. CT scores of ground-glass were 4. 25(n=2),3.75 (n=1),2.25(n=1),1.75(n=1),1.00(n=6),0.75(n=2), 0.50(n=2),0(n=4).CT scores of consolidation were4.25(n=1),4.00(n=1),3.75 (n=1), 2.75(n=1),1.25(n=3),1.00(n=2),0.75(n=2),0.50(n=1),0.25(n=3),0(n=4). CT scores of ground-glass were significantly correlated with the fever time (r= 0.776, P < 0.01), CT scores of consolidation had no correlation with the fever time(r=0.322,P > 0.01). Conclusions The most common CT findings in patients with S-OIV infection are diffuse distribution of bilateral ground-glass opacities with or without associated focal or multifocal areas of consolidation. The increasing of ground-glass's range could be the marker of progression of H1N1 pulmonary infection at initial stage.

MR diffusion weighted imaging for quantification of liver fibrosis in patients with chronic viral hepatitis / 中华放射学杂志

Objective The study was to evaluate DWI for quantifying liver fibrosis. Methods A total of 12 volunteers, 47 patients who had chronic HBV or HCV hepatitis and underwent liver biopsy [Scheuer score for fibrosis(S) and inflammation(G)] were enrolled in this study. They were scanned using a 1.5 T MR unit with b value of 0,250,500,750, 1000 s/mm~2. ADCs at b_(250-1000) and b_(500-1000) were the average ADCs of b=250, 500, 750, 1000 s/mm~2 and b=500, 750, 1000 s/mm~2. The studied the correlation between Scbeuer scores and ADC values, and conducted Mann-Whitney U test and Logistic regression to evaluate ADC for prediction of fibrosis scores. Results The average ADCs were (1.41± 0.11),(1.37±0.09), (1.27±0.05), (1.26±0.04), (1.22±0.06) mm~2/s respectively from SO to S4, stage at b=750 s/mm~2 (F=18.31, P<0.01). With the increase of fibrosis score, the average ADC decreased gradually, the two were better negatively correlated at b_(250-1000)(r=-0.727, P<0.01) than other b values. Using b_(750) and the two combined b values, the found significantly lower ADCs in S2 or greater versus S1 or less and in S3 or greater versus S2 or less fibrosis (P<0.01). The best predictor for S2 or greater was b_(750) with the largest AUC of 0.909, sensitivity of 85.7%, and specificity of 100.0% (ADC ≤1.35×10~(-3) mm~2/s). The best predictor for S3 or greater was b_(250-1000) with the largest AUC of 0.864, sensitivity of 69.6%, and specificity of 95.8% (ADC≤1.53×10~(-3) mm~2/s). Conclusion DWI can be a good predictor for scoring liver fibrosis for S2 or S3 stage above, while b_(750) and the combined b values are suitable for evaluation.

Application of energy subtract angiography of dual source CT in diagnosis of arterial diseases of the lower extremities / 中国医学影像技术

Objective To observe the value of dual source CT (DSCT) dual energy subtract method in diagnosis of lower extremity arterial occlusion. Methods Thirty-two patients with lower extremity arterial occlusive diseases underwent DSCT direct bone removal CT angiography (DE-BR-CTA) and digital subtraction angiography (DSA) within 2 weeks. Raw data were reconstructed with techniques including MIP and VR. Arterial visibility of DE-BR-CTA was analyzed by two experienced radiologists taking DSA as the standard. Results A total of 328 arterial segments were selected in 32 patients with lower extremity arterial occlusive diseases. The correlation between DSA and DE-BR-CTA was good. There was no significant difference in arterial visibility between DE-BR-CTA and DSA (P＞0.05). Compared with DSA, 12 of the segmental stenosis were overestimated and 6 were underestimated with DE-BR-CTA. When stenosis was over 10%, the accuracy, sensitivity, specificity, positive predictive value and negative predictive value of DE-BR-CTA was 94.51%, 96.15%, 93.02%, 92.59% and 96.39%, respectively. Conclusion DSCT energy subtraction angiography is an accurate diagnostic method and non-invasive imaging technology in the assessment of lower extremity arterial occlusive diseases. It may provide precious information for pre-surgery evaluation and screening the arterial diseases of the lower extremities.