Objective To observe the value of nomogram based on echocardiographic functional parameters of left atrium(LA)for identifying atrial fibrillation(AF).Methods Sixty-six adult patients with AF and 65 individuals without AF were retrospectively enrolled and randomly divided into training set(n=79)and test set(n=52).Four-dimensional LA volumetric echocardiography was performed,and LA volume and strain parameters were measured using four-dimensional left atrial automatic quantification(4D LAQ)technology.Echocardiographic parameters were compared between AF group(n=38)and non-AF group(n=41)in training set,and a logistic regression model for identifying AF was constructed.The performance of the model was evaluated with receiver operating characteristic(ROC)curve and the area under the curve(AUC).Then a nomogram was developed based on the logistic regression model,and the calibration was assessed using a calibration curve,as well as the clinical net benefit was evaluated through decision curve analysis(DCA).Results In training set,compared to those in non-AF group,LA diameter(LAD),the minimum LA volume(LAVmin),the maximum LA volume(LAVmax)and the maximum LA volume index(LAVImax)increased,while the left ventricular ejection fraction(LVEF),LA emptying volume(LAEV),LA emptying fraction(LAEF),and the magnitude of LA reservoir longitudinal strain(LASr)and LA reservoir circumferential strain(LASr_c)decreased in AF group(all P＜0.05).LASr(OR[95％CI]=0.780[0.636,0.956])and LAEF(OR[95％CI]=0.850[0.757,0.954])were both independently associated with AF.The logistic regression model constructed for identifying AF achieved an AUC of 0.950 in training set and 0.955 in test set.The nomogram demonstrated good calibration and provided a certain level of net clinical benefit.Conclusion Nomogram constructed on basis of LASr and LAEF was effective for identifying AF.

Objective To observe the value of nomogram based on echocardiographic functional parameters of left atrium(LA)for identifying atrial fibrillation(AF).Methods Sixty-six adult patients with AF and 65 individuals without AF were retrospectively enrolled and randomly divided into training set(n=79)and test set(n=52).Four-dimensional LA volumetric echocardiography was performed,and LA volume and strain parameters were measured using four-dimensional left atrial automatic quantification(4D LAQ)technology.Echocardiographic parameters were compared between AF group(n=38)and non-AF group(n=41)in training set,and a logistic regression model for identifying AF was constructed.The performance of the model was evaluated with receiver operating characteristic(ROC)curve and the area under the curve(AUC).Then a nomogram was developed based on the logistic regression model,and the calibration was assessed using a calibration curve,as well as the clinical net benefit was evaluated through decision curve analysis(DCA).Results In training set,compared to those in non-AF group,LA diameter(LAD),the minimum LA volume(LAVmin),the maximum LA volume(LAVmax)and the maximum LA volume index(LAVImax)increased,while the left ventricular ejection fraction(LVEF),LA emptying volume(LAEV),LA emptying fraction(LAEF),and the magnitude of LA reservoir longitudinal strain(LASr)and LA reservoir circumferential strain(LASr_c)decreased in AF group(all P＜0.05).LASr(OR[95％CI]=0.780[0.636,0.956])and LAEF(OR[95％CI]=0.850[0.757,0.954])were both independently associated with AF.The logistic regression model constructed for identifying AF achieved an AUC of 0.950 in training set and 0.955 in test set.The nomogram demonstrated good calibration and provided a certain level of net clinical benefit.Conclusion Nomogram constructed on basis of LASr and LAEF was effective for identifying AF.

Objective To evaluate the feasibility of T2 *mapping T2 *value combined with DWI ADC value in quantitative assessment of the activity of sacroiliitis.Methods 30 patients diagnosed with ankylosing spondylitis (AS)were divided into 2 groups as acute group (n=17)and chronic group (n=13)according to the BASDAI scores of the clinical severity of disease.And 20 healthy adults were recruited as control group.All groups were examined by MR with traditional sequence,T2 *mapping and DWI in the sacroiliac joint.The T2 *value and ADC value of the bone marrow edema region and normal region were measured.Furthermore,the imaging data and the clinical scores were statistical analysis and compared among three groups.Results T2 *values and ADC values in acute group of AS patients were higher than chronic group (P<0.05),as well as compared with healthy volunteers (P<0.05).There was no statistically significant difference between the chronic group of AS patients and control group (P>0.05).Positive correlation between ADC value and BASDAI was observed in patients group.Conclusion T2 *mapping combined with DWI imaging in AS is beneficial for early diagnosis and quantitative analysis of the activity of sacroiliitis.