[Clinical value of MRI in the diagnosis of Brucellosis spondylitis]

Objective: To analyze the MRI characteristics of Brucellosis spondylitis (BS) and evaluate the clinical value of MRI in the diagnosis of BS. Methods: A total of 47 patients clinically diagnosed as BS from General Hospital of Jizhong Energy Xingtai Mining Industry Bloc and Xingtai Second Hospital from January 2015 to December 2017 were collected, including 32 males and 15 females, aged 24-77 years, with an average age of (57±11) years, and the course of disease was 1 month-2 years. Routine spinal MRI sequence were acquired for patients. Images were assessed by two senior imaging diagnostic physician independently. The evaluation included signal changes in the affected area of the vertebral body, vertebral body and intervertebral disc, the signal of paravertebral soft tissue, the signal of abscess around the vertebral body, whether the dural sac, spinal cord and nerve root were compressed or not, and its signal changes. Results: (1) Spinal involvement, in 47 patients with BS, 112 vertebral bodies were involved, including 11 cervical vertebrae (9.8%), 5 thoracic vertebrae (4.5%), 91 lumbar vertebrae (81.2%), and 5 sacral vertebrae (4.5%), the lumbar vertebrae was dominant. (2) MRI features, 112 vertebral bodies were involved, including 105 (93.8%) vertebral bodies morphology showed no significant changes, only 7 (6.2%) vertebral bodies showed mild collapse changes; 71 vertebral bodies showed diffuse destruction (63.4%), and 41 vertebral bodies showed localized destruction (36.6%). Among the 47 cases, 40 cases were continuous destruction of adjacent vertebral bodies, 6 cases showed non-adjacent damage; 37 cases of intervertebral disc involvement; 29 cases of narrowing of intervertebral space; 11 cases of paravertebral soft tissue swelling and 28 cases showed paravertebral abscess. Conclusion: MRI has certain characteristics in the diagnosis of Brucella spondylitis and has a high clinical value in the differential diagnosis of spinal disease.

[Quantitative evaluation of the relationship between femoral trochlear dysplasia and the degeneration of the patellofemoral cartilage by using T2mapping]

Objective: To evaluate the relationship between the femoral trochlear dysplasia(FTD) and the degeneration of the patellofemoral cartilage by using MR T2mapping technique. Methods: Sixty two subjects with FTD(aged 18-45 years) were enrolled in Tianjin First Center Hospital from January 2016 to December 2017,the controls which both age and gender were matched.T2mapping scan were aquired for each subject and control. Compare the differences of the T2mapping values for each area between subjects and controls, and compare Dejour types of femoral trochlear in different age groups, respectively. Results: The T2mapping value of subjects was significant lower than controls: the superficial-femoral-lateral layer (sFL) (P=0.000) and the superficial-patella-lateral layer (sPL) (P=0.009). In the group of age less than 30 years, the T2mapping value of subjects was significant lower than controls:sFL (P=0.001) and sPL (P=0.015). In group of age greater than 30 years, the T2mapping value of subjects was significant lower than controls: sFL (P=0.035). In difference Dejour types of FTD, the T2mapping value of type B-D was lowest in sFL(P=0.014),sPL(P=0.000), the superficial-patella-medial layer (sPM) (P=0.020) and the the T2mapping value of type B-D was highest in the deep-femoral-medial layer (dFM) (P=0.006). The difference was statistically significant, P<0.05. Conclusion: The FTD might cause the early degeneration of patellofemoral cartilage, which significantly appear in the young age; The type B-D of FTD is more likely to cause the wider range of superficial cartilage injure and involved some part of deep layer; the injure shows dehydration change in superficial cartilage and edema in deep layer.

Spin-reorientation critical dynamics in the two-dimensional XY model with a domain wall

In recent years, static and dynamic properties of non-180^{∘} domain walls in magnetic materials have attracted a great deal of interest. In this paper, spin-reorientation critical dynamics in the two-dimensional XY model is investigated with Monte Carlo simulations and theoretical analyses based on the Langevin equation. At the Kosterlitz-Thouless phase transition, the dynamic scaling behaviors of the magnetization and the two-time correlation function are carefully analyzed, and critical exponents are accurately determined. When the initial value of the angle between adjacent domains is slightly lower than π, a critical exponent is introduced to characterize the abnormal power-law increase of the magnetization in the horizontal direction inside the domain interface, which is measured to be ψ=0.0568(8). In addition, the relation ψ=η/2z is analytically deduced from the Langevin dynamics in the long-wavelength approximation, well consistent with numerical results.

[Value of mDIXON-Quant sequence, diffusion-weighted imaging in quantitatively diagnosing the sacroiliitis stages]

Objective: To evaluate the value of mDIXON-Quant sequence, diffusion-weighted imaging (DWI) in quantitative diagnosing of the sacroiliitis stages in patients with ankylosing spondylitis (AS). Methods: Based on the Bath Ankylosing Spondylitis Activity Index (BASDAI) and laboratory parameters, a total of 51 patients were diagnosed with AS. They were divided into two groups as early active group (n=20) and chronic active group (n=31), and at the same time, 25 healthy people from Tianjin were included as control group. The regular MRI sequences and mDIXON-Quant sequence, DWI were obtained. The apparent diffusion coefficient (ADC) and fat-signal fraction (FF) value of bone marrow with edema of the sacroiliac joints in early active group and chronic active group and of subchondral bone marrow of sacroiliac joint in control group all were measured by ADC maps and FF maps. Mean (FF, ADC) values were compared between groups. Results: The ADC value of the early active group, chronic active group and the control group is (1.07±0.20)×10(-3)mm(2)/s, (1.00±0.22)×10(-3)mm(2)/s, (0.25±0.07)×10(-3)mm(2)/s, respectively, and the differences of ADC value between early active group and control group, chronic active group and control group were significant (P<0.01), but the difference of the ADC value between early active group and chronic active group was not significant (P=0.394). That is to say, the ADC value can't distinguish the early active group and chronic active group. The differences of FF value between groups was significant (P<0.01), and the FF value of bone marrow with edema in chronic active group were higher than that in early active group. Conclusions: The mDIXON-Quant sequence can quantitatively diagnose early active group and chronic active group, and the diagnostic value is better than DWI. Thus, it can provide guidance for clinical treatment and prognosis.

[Predictive value of dynamic enhanced MR synovial wash in rate in progression to rheumatoid arthritis in patients with undifferentiated arthritis]

Objective: To investigate the predictive value of dynamic enhanced MR synovial wash in rate (WASHIN) in progression to rheumatoid arthritis (RA) in patients with undifferentiated arthritis (UA). Methods: The data of dynamic enhanced MR synovial WASHIN and C- reactive protein (CRP) of 33 patients with UA were analyzed between October 2014 and January 2016 from Tianjin First Center Hospital, so as to evaluate the correlation between the two indicators. According to the value of CRP, the patients were divided into two groups, the CRP>8 mg/L for CRP positive group (18 cases), CRP≤8 mg/L for CRP negative group (15 cases). Ranked sum test was used to compare the difference of WASHIN between two groups. The ROC curve analysis was carried out to test the diagnostic power of WASHIN. Results: In 33 patients with UA, the correlation between WASHIN and CRP was positive, r=0.767, P<0.01; as for the WASHIN, there was significant difference between CRP positive group(49.51±19.79)/s and CRP negative group(19.90±14.51)/s (P<0.01). 9 cases were clinically diagnosed with RA during follow-up, of which 8 cases for CRP positive group and 1 case for CRP negative group. The biggest area under the ROC curve of synovial WASHIN was 0.944, the biggest Youden index was 0.85, sensitivity was 100.0%, specificity was 87.5%. 2 cases were clinically diagnosed with osteoarthrosis during follow-up, synovial WASHIN respectively of 18.42 and 21.48 /s. Conclusion: Synovial WASHIN can improve the sensitivity and specificity to predict the prognosis from UA to RA, and can provide certain guiding significance for clinical work.

Short-time critical dynamics and aging phenomena in the two-dimensional XY model

With Monte Carlo methods, we simulate dynamic relaxation processes of the two-dimensional XY model at the Berezinskii-Kosterlitz-Thouless phase transition temperature and below, starting from both ordered and disordered initial states. The two-time correlation function A(t',t) is measured, and aging phenomena are investigated. The power-law correction in the spatial correlation length xi(t) for relaxation with an ordered initial state and the logarithmic correction for relaxation with a disordered initial state are carefully analyzed. The scaling functions of A(t',t) are then extracted.