ABSTRACT
Objective To investigate the diagnostic value of texture analysis derived from conventional MR imaging in differentiating benign and malignant breast lesions. Methods Thirty-six patients with malignant breast lesion and 33 patients with benign breast lesion were retrospectively analyzed in our study. All patients underwent conventional MR imaging including axial T1WI, T2WI, and contrast-enhanced T1WI before surgery. Texture features were calculated from manually drawn ROIs by using MaZda software. The feature selection methods included mutual information (MI), Fishers coefficient, classification error probability combined with average correlation coefficients (POE + ACC) and the combination of the above three methods(FPM). These methods were used to identify the most significant texture features in discriminating benign breast lesion from malignant breast lesion. The statistical methods including raw data analysis (RDA), principal component analysis (PCA), linear discriminant analysis (LDA) and nonlinear discriminant analysis (NDA) were used to distinguish malignant breast lesion from benign breast lesion. The results were shown by misclassification rate. Results In the three kinds of sequences, the texture features for differentiating malignant breast lesion and benign breast lesion were mainly from T2WI which had the lowest misclassification rate 4.35%(3/69). The misclassification rates of the feature selection methods were similar in MI, Fisher coefficient and POE+ACC (15.94%to 56.52%for MI;17.39%to 56.52%for Fisher coefficient and 17.39%to 56.52%for POE+ACC). However, the misclassification rate of the combination of the three methods (4.35%to 53.62%for FPM) was lower than that of any other kind of method. In the statistical methods, NDA (4.35% to 27.54%) had lower misclassification rate than RDA (33.33% to 56.52%), PCA (33.33% to 53.62%) and LDA (15.94% to 44.93%). Conclusion Texture analysis of conventional MR imaging can provide reliably objective basis for differentiating benign from malignant breast lesions.
ABSTRACT
Objective To study the changing of vertebral body marrow fat fraction(FF) in different age and sex and the relation-ship between FF and bone mineral densities (BMD). Methods Eighty-five healthy volunteers aged from 21 to 70 years old and twenty patients with osteoporosis based on T score after dual X-ray absorptionmetry examination underwent proton magnetic reso-nance spectroscopy (MRS) in L_3 vertebral bodies. The volunteers were divided into five groups according to the age(10 years and 16～18 cases in each group). Results The FF values in 21～30 years group,31～40 years group,41～50 years group,51～60 years group , >60 years group and the osteoporotic group were 30.7%±4.4%, 35.5%±6.8% , 41.9%±6.6%, 46.8%±5.5%, 51.7%±5.2% and 59.2%±7.4%, respectively. The FF values in L_3 vertebral bone marrow in men were high than that in women in the same age group (P<0.05) except >60 years group. There was negative correlation between marrow fat content and T score in osteoporotic group(γ=-0.6, P<0.01). Conclusion The vertebral marrow fat content in healthy adults was significantly in-creased with the aging. MRS may be used as a new way to evaluate the physiological and pathological process of bone marrow.
ABSTRACT
OBJECTIVE@#To study dynamic change and pathophysiology of airway obstruction of the soft palate in patients with obstructive sleep apnea hypopnea syndrome (OSAHS) during wakefulness and natural sleep.@*METHOD@#Sixteen patients who were diagnosed as OSAHS by sleep questionnaires, medical examination and polysomnography were enrolled in this study in Shanghai Tenth People' Hospital from May to December during 2007. All patients were requested to keep awake prior to examination. Sequential midline sagittal images of the upper airway were obtained during awake and asleep state with Cine-MRI and been transmitted to portable computer. Morphologic change of the soft palate, the anterior-posterior pendulum angle of the soft palate, the anteroposterior diameter and the length of soft palate were measured. Statistical analysis was performed with paired t-test.@*RESULT@#During wakefulness: soft palate caused obstruction by floating backwards and widening anteroposterior diameter(distance between hard palate and uvula P > 0.05, included angle of hard palate and segmental vente of uvula P 0.05, included angle of hard palate and segmental dorsum of uvula P > 0.05, difference of included angle P < 0.01). Main obstruction site was on retroglottal region.@*CONCLUSION@#Morphologic change of soft palate in patients with OSAHS is multiple, and level of obstruction is deeper during natural sleep than during wakefulness. Main reason of airway obstruction is distinct during different state. The obstruction of upper airway of patients with OSAHS during wakefulness can't replace that during natural sleep.