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PurposeTo identify differences in CT imaging and clinical features between COVID-19 and influenza pneumonia in the early stage, and to identify the most valuable features in the differential diagnosis. Materials and MethodA consecutive cohort of 73 COVID-19 and 48 influenza pneumonia patients were retrospectively recruited from five independent institutions. The courses of both diseases were confirmed to be in the early stages (2.66 {+/-} 2.62 days for COVID-19 and 2.19 {+/-} 2.10 days for influenza pneumonia after onset). The chi-square test, students t-test, and Kruskal-Wallis H-test were performed to compare CT imaging and clinical features between the two groups. Spearman or Kendall correlation tests between feature metrics and diagnosis outcomes were also assessed. The diagnostic performance of each feature in differentiating COVID-19 from influenza pneumonia was evaluated with univariate analysis. The corresponding area under the curve (AUC), accuracy, specificity, sensitivity and threshold were reported. ResultsThe ground-glass opacification (GGO) was the most common imaging feature in COVID-19, including pure-GGO (75.3%) and mixed-GGO (78.1%), mainly in peripheral distribution. For clinical features, most COVID-19 patients presented normal white blood cell (WBC) count (89.04%) and neutrophil count (84.93%). Twenty imaging features and 6 clinical features were identified to be significantly different between the two diseases. The diagnosis outcomes correlated significantly with the WBC count (r=-0.526, P<0.001) and neutrophil count (r=-0.500, P<0.001). Four CT imaging features had absolute correlations coefficients higher than 0.300 (P<0.001), including crazy-paving pattern, mixed-GGO in peripheral area, pleural effusions, and consolidation. ConclusionsAmong a total of 1537 lesions and 62 imaging and clinical features, 26 features were demonstrated to be significantly different between COVID-19 and influenza pneumonia. The crazy-paving pattern was recognized as the most powerful imaging feature for the differential diagnosis in the early stage, while WBC count yielded the highest diagnostic efficacy in clinical manifestations.
ABSTRACT
Objective@#To investigate the changes of 31P-MRS in denervated skeletal muscle at 7.0 T MR system.@*Methods@#In the experiment group, a total of 18 male Sprague-Dawley rats aged 6-8 weeks old and weighing 200-250 g were obtained. The right posterior femoral nerve were transected, and the proximal stumps were ligated by using 5-0 nylon stitches to preclude spontaneous repair. A sham surgery (incision and exploration of the nerve) was performed at the same time (n=6). Before rat model established and at varying times after initial surgery (3 d, and 1, 2, 4, 6, and 8 weeks). 31P-MR spectra of rat quadriceps femoris were acquired on 7.0 T Agilent small animal MR imaging system. We quantified the phosphocreatine (PCr), adenosine triphosphate(β-ATP), and inorganic phosphate (Pi) using Creatine phosphate disodium salt(10 mmol/L) as an external standard. The ratios, include PCr/Pi, Pi/β-ATP, PCr/β-ATP, PCr/(PCr+Pi) and Pi/(PCr+Pi) were quantified in jMRUI. All data were analyzed by one way analysis of variance (ANOVA) with posttest inter-group comparisons using Bonferroni test. Comparative analysis methods between the experimental and control group were performed via independent samples t test. P<0.05 was considered as statistically significance.@*Results@#The average measured concentrations of β-ATP, PCr, and Pi in control groups were (6.654±0.178) μmol/g, (25.656±0.738) μmol/g, and (1.594±0.096) μmol/g, respectively. There were significant statistically differences in β-ATP, PCr, Pi, PCr/Pi, PCr/PCr+Pi,Pi/PCr+Pi between the study and control group(P<0.05) at any measurement time point after denervation. Pi/β-ATP,PCr/β-ATP and pHi in the experimental group significantly statistically differed from those of the control group (all P<0.05)at each time point except on day 3 after operation. The total concentrations of β-ATP and PCr were reduced by 11.5% and 19.7% respectively on day 3. Thereafter, β-ATP and PCr declined rapidly by 63.1% and 68.8% at week 4 respectively, then decreased slowely by 74.0%和82.3% till week 10. The change of PCr/Pi is similar to β-ATP and PCr, but more remarkable. Pi, Pi/PCr+Pi, Pi/ATP showed a progressively increase till week 10. The intra-cellular pH (pHi) of normal rat muscles was 7.033±0.017, While the pHi gently in experiment rat muscles decreased during the entire experiment.@*Conclusion@#31P-MRS with 7.0 T can quantify the temporal changes of energy metabolism and pHi in normal and denervated rat muscles. It shows that the dysfunction of energy metabolism are progressive with time and that they begin within a short period following the nerve section, the change of β-ATP, PCr, PCr/Pi take place primarily within 4 weeks after denervation. β-ATP, PCr, and PCr/Pi may be potential biomarkers of energy metabolism in the evaluation of denervated muscle atrophy.
