Objective To investigate the value of ultrasound in differential diagnosis of benign and malignant thyroid lesions with rimlike peripheral calcification.Methods Seventy-three patients of thyroid nodules with rimlike peripheral calcification were analyzed retrospectively.All cases were confirmed by surgery and pathology.The efficacy of sonographic features on diagnosis of thyroid nodules was analyzed.Results Among 73 patients,58 (58/73,79.45％) were benign and 15 (15/73,20.55％) were malignant.Among the sonographic features mentioned,the mean size,margin,internal echo and presence of halo showed no significant differences between malignant and benign nodules (all P＞0.05).Proportion of thyroid nodules coexisting with nodular goiter,irregular thickness and interruption of rimlike peripheral calcification had significant differences between malignant and benign nodules (all P＜0.05).The sensitivity,specificity,positive predictive value and negative predictive value of coexisting with nodular goiter for diagnosing benign nodules were 77.59％ (45/58),60.00％ (9/15),88.24 ％ (45/51),40.91％ (9/22),respectively.The sensitivity,specificity,positive predictive value and negative predictive value of irregular thickness for diagnosing malignant nodules were 53.33 ％ (8/15),87.93％ (51/58),53.33％ (8/15),87.93％ (51/58),respectively.The sensitivity,specificity,positive predictive value and negative predictive value of interruption of rimlike peripheral calcification for diagnosing malignant nodules were 73.33％ (11/15),68.97％ (40/58),37.93％ (11/29),90.91％ (40/44),respectively.Conclusion Ultrasonography is helpful to diagnosis of thyroid nodules with rimlike peripheral calcification.Irregular thickness and interruption of calcification are associated with malignancy.

Objective To evaluate morphological structure of uterosacral ligament (USL) and cardinal ligament (CL) in patients with severe pelvic organ prolapse (POP) by MRI technology, and to analysis and discuss its clinical significance. Methods From November 2013 to February 2014 in Peking University People′s Hospital, 26 elderly patients withⅢ-Ⅳdegree of POP were selected as the POP group and 18 healthy elderly volunteers were selected as the control group during the same period. Pelvic MRI examination were performed in the two groups. The morphological characteristics of left and right side of the uterosacral-cardinal ligament on MRI and the attachment site of the starting and ending points between two group were described and compared. Results In POP group, 25 cases of left USL starting point were located in the sacrospinous ligament/coccygeal muscle complex [58% (15/26)] or coccygeal muscle [38%(10/26)], ending point were located in the cervix and vagina [58%(15/26)] or cervix [38%(10/26)];24 cases of right USL starting point were located in the sacrospinous ligament/coccygeal muscle complex [31%(8/26)]or coccygeal muscle [62%(16/26)], 26 cases of right USL ending point were located in the cervix and vagina [62% (16/26)] or cervix [38% (10/26)]; the left and right CL in the POP group and the control group were both from the sacroiliac joint at the top of the greater sciatic foramen from the ipsilateral pelvic side wall;1 case (4%, 1/26) of left CL in the POP group completely connected to the bladder, 10 cases (38%, 10/26) partly connected to the bladder;14 cases (54%, 14/26) of right CL partly connected to the bladder, the rest ending points of left and right CL were located in cervix and (or) vagina. In the control group, 17 cases of left USL starting point were located in the sacrospinous ligament/coccygeal muscle complex (10/18) or coccygeal muscle (7/18), ending point were located in the cervix and vagina (12/18) or cervix (6/18);18 cases of right USL starting point were located in the sacrospinous ligament/coccygeal muscle complex (10/18) or coccygeal muscle (8/18), ending point were located in the cervix and vagina (13/18) or cervix (5/18);8 cases (8/18) of left CL partly connected to the bladder;15 cases (15/18) of right CL partly connected to the bladder, the rest ending points of left and right CL were located in cervix and (or) vagina. There was no significant difference between the two groups on the starting and ending points (P>0.05). Conclusions The observation of MRI could be consistent with the clinical anatomy on the starting and ending points, direction of travel in the uterosacral-cardinal ligament. The starting and ending points of the left and right side USL and the ending points of the left and right side CL are not completely symmetrical, the variation degree is large, some CL could be completely or partly inserted to the bladder.

Objective To establish the finite element model of uterosacral ligament (USL) and cardinal ligament (CL) and analyze the stress distribution and deformation with USL and CL under different working conditions. Methods Patients with stage Ⅲ-Ⅳpelvic organ prolapse (POP) and healthy female volunteers were selected for research subject, and divided into anterior uterus group and posterior uterus group. Two POP patients and two volunteers were selectd into the anterior uterus group and posterior uterine group respectively. Pelvic MRI scan was performed in two groups. Based on the original MRI data sets, the finite element model of USL and CL was constructed by using the software such as the Mimics, and the stress distribution and deformation of USL and CL were simulated. Results Under the premise of the elastic modulus fixed and three different working conditions such as 60 cmH2O, 99 cmH2O and 168 cmH2O (1 cmH2O=0.098 kPa) with abdominal pressure generated by maximum Valsalva maneuver, according to the present conditions and the simulation, the trend was analyzed: the stress and deformation of the uterus, anterior vaginal wall, USL and CL in two groups were mainly distributed in the middle and lower part of the anterior vaginal wall or the ligament and the cervix-vagina junction, the maximum stress and the maximum displacement were mainly concentrated in the lower region of the anterior vaginal wall. With increasing of abdominal pressure generated by the maximum Valsalva maneuver, the maximum stress values of the POP patient in anterior uterus group under three different working conditions were: 0.027 9, 0.046 0, 0.078 0 MPa, and the maximum displacement values were: 9.145 5, 15.090 0, 25.607 0 mm. The maximum stress values of the volunteer in anterior uterus group under three different working conditions were:0.012 6, 0.020 8, 0.035 3 MPa, and the maximum displacement values were: 1.816 7, 2.997 5, 5.086 7 mm. The maximum stress values of the POP patient in posterior uterine group under three different conditions were: 0.069 4, 0.114 6, 0.194 5 MPa, and the maximum displacement values were:11.658 0, 19.236 0, 32.643 0 mm. The maximum stress values of the volunteer in posterior uterus group under three different working conditions were:0.009 1, 0.015 1, 0.025 6 MPa, and the maximum displacement values were:2.581 6, 4.259 6, 7.228 4 mm. The maximum stress values and the maximum displacement values were all increased with increasing of abdominal pressure in the two groups. The maximum stress values and the maximum displacement values of the POP patients were greater than those of volunteers. Under different working conditions, the maximum stress values and maximum displacement values of the posterior uterus POP patient were all greater than those of the anterior uterus POP patient. Conclusions The finite element model of USL and CL is completely based on the MRI technology and the model is real and reliable. The increase of abdominal pressure will produce a larger stress and deformation of USL and CL, which is one of the reasons causing the injury of the ligament.

Objective To investigate the influence of gravity levels on lower limb motions during human walking. Methods A suspended microgravity simulation system was designed for the experiment. Kinetic parameters from lower limb joints of twelve volunteers during walking were measured by the motion capture system and 3D force plate under simulated Mars gravity (1/3 G), lunar gravity (1/6 G) and earth gravity (1 G). Results Under simulated Mars and lunar gravity, the ranges of motion (ROMs) of hip and knee joints in sagittal plane significantly decreased (P＜0.01) while the ROMs of ankle joints obviously increased (P＜0.05). The ROMs of hip, knee and ankle joints in sagittal plane under earth gravity were 45.2°, 67.7°, 32.5°, respectively, while the ROMs of hip, knee and ankle joints under lunar gravity were 25.1°, 50.8°, 42.4°, respectively. In addition, the force and torque of lower limb joints in sagittal plane under lower gravity also decreased significantly (P＜0.01). Conclusions The results obtained by this study were almost the same as the research findings obtained by using treadmill. Astronauts can use the treadmill and microgravity simulation system for walking exercises under lunar gravity on the earth.