[Clinical applications of apparent diffusion coefficient value for evaluation of hip joint of ankylosing spondylitis active lesions].

OBJECTIVE: To evaluate the apparent diffusion coefficient (ADC) value in differential diagnosis of ankylosing spondylitis active lesions. METHOD: A total of 68 patients with AS involving hip joint who were diagnosed in Third Affiliated Hospital of Southern Medical University form March 2010 to December 2014 were evaluated by MRI. The ADC values of the hip joint lesions were measured and compared in 38 cases of ankylosing spondylitis active lesions (active group) and 30 cases of ankylosing spondylitis in stable period (stable group), all cases were confirmed by clinical diagnosis. RESULTS: There are 238 lesions were detected demonstrating hyperintens in DWI and ADC picture. The mean ADC values of active group and stable group were (1.00 ± 0.13) × 10⁻³ mm²/s and (0.65 ± 0.12) × 10⁻³ mm²/s (t=-11.85, P=0.00). The correlation coefficient between ADC and BASDAI score is 0.831 (P<0.01). ROC curve showed that the threshold ADC value differentiating active group and stable group was 0.81 × 10⁻³ mm²/s, with a sensitivity of 94.7%and specificity of 90%. CONCLUSION: The ADC value of hip joint lesion of AS patient can help to determine the nature of the ankylosing spondylitis.

[Multiple linear regression and ROC curve analysis of the factors of lumbar spine bone mineral density].

OBJECTIVE: To investigate the correlation between the lumbar vertebra bone mineral density (BMD) and age, gender, height, weight, body mass index, waistline, hipline, bone marrow and abdomen fat, and to explore the key factor affecting the BMD. METHODS: A total of 72 cases were randomly recruited. All the subjects underwent a spectroscopic examination of the third lumber vertebra with single-voxel method in 1.5T MR. Lipid fractions (FF%) were measured. Quantitative CT were also performed to get the BMD of L3 and the corresponding abdomen subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT). The statistical analysis were performed by SPSS 19.0. RESULTS: Multiple linear regression showed except the age and FF% showed significant difference (P<0.05) , the gender, height, weight, BMI, waistline, hipline, SAT and VAT showed no significant difference (P>0.05). The correlation of age and FF% with BMD was statistically negatively significant (r=-0.830, -0.521, P<0.05). The ROC curve analysis showed that the sensitivety and specificity of predicting osteoporosis were 81.8% and 86.9%, with a threshold of 58.5 years old. And it showed that the sensitivety and specificity of predicting osteoporosis were 90.9% and 55.7%, with a threshold of 52.8% for FF%. CONCLUSION: The lumbar vertebra BMD was significantly and negatively correlated with age and bone marrow FF%, but it was not significantly correlated with gender, height, weight, BMI, waistline, hipline, SAT and VAT. And age was the critical factor.

[Correlation between vertebral bone marrow fat and abdomen fat: a prospective study].

OBJECTIVE: To investigate the correlation between the lumbar bone marrow fat and abdominal fat. METHODS: A total of 68 individuals (32 men and 36 women, aged 21-74 years with a median of 49.5 years) were included in this study. All the subjects underwent spectroscopic examination of the third lumber vertebra with the single voxel method on a 1.5T MR scanner to measure the fat fraction (FF%). Quantitative CT was also performed for measurement of the abdomen subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT). The measurements were compared between subjects aged ≥50 years and those below 50 years, respectively,in male or female subjects. RESULTS: In male subjects, BMI, FF%, VAT or SAT showed no significant differences between the two age groups (P>0.05), and FF% was not correlated with BMI, VAT or SAT (r=0.109, 0.034, 0.066, respectively; P>0.05). In the female subjects, BMI, FF%, VAT and SAT differed significantly between the two age groups (P<0.05), and in ≥50 years group, FF% showed a positive correlation with VAT (r=0.499, P<0.05) but was not correlated with SAT (r=0.221, P>0.05); in<50 years group, FF% was not correlated with VAT or SAT (r=0.076, -0.067, respectively; P>0.05). CONCLUSION: FF% is positively correlated with VAT in female subjects aged beyond 50 years, but is not correlated with VAT or SAT in male subjects or in younger female subjects.