Hipbone biomechanical finite element analysis and clinical study after the resection of ischiopubic tumors.

OBJECTIVE: To investigate the changes of hipbone biomechanics after the resection of ischiopubic tumors and their relationships with the complications in the convalescent stage, and directing the postoperative pelvic reconstruction. METHODS: DICOM data were used to create an intact hipbone finite element model and postoperative model. The biomechanical indices on the same region in the two models under the same boundary condition were compared. The differences of displacement, stress, and strain of the two models were analyzed with statistical methods. RESULTS: The distribution areas of the hipbone nodes' displacement, stress, and strain were similar before and after the simulated operation. The sacroiliac joint nodes' displacement (P=0.040) and strain (P=0.000), and the acetabular roof nodes' stress (P=0.000) and strain (P=0.005) of two models had significant differences, respectively.But the sacroiliac joint nodes' stress (P=0.076) and the greater sciatic notch nodes' stress (P=0.825) and strain (P=0.506) did not have significant differences. CONCLUSIONS: The resection of ischiopubic tumors mainly affect the biomechanical states of the homolateral sacroiliac joint and acetabular roof. The complications in the convalescent stage are due to the biomechanical changes of the sacroiliac joint and the acetabular roof and disappearances of the stabilization and connection functions of the pubic symphysis and superior ramus of pubis.

CT findings of Madelung's disease in the head and neck region / 中华放射学杂志

Objective To investigate the CT findings of Madelung's disease in the head and neck region,and to evaluate the value of CT in demonstrating the Madelung's disease in the head and neck region.Methods CT findings of Madelung's disease in the head and neck region in 7 cases were analyzed retrospectively.All were males,with the age from 36 to 60 years,mean 51 years.All patients were underwent CT native scan,and enhanced CT scan was performed on 3 of them.Results CT images in the neck of all patients showed accumulation of nonencapsulated fat within the subcutaneous tissue and(or) deep to the platysma,and(or)within the spaces between the muscles.The fat deposits were ill-defined and symmetrical.In most cases the fat deposits involved the anterior part of the neck(infrahyoid and suprahyoid),submandibular region,the subcutaneous tissue of the nape and deep to the stenomastoid muscles.Conclusions Madelung's disease in the head and neck region have characteristic CT findings,and CT has great value in qualitative and quantitative diagnosis in Madelung's disease.

Multi-slice spiral CT urography in the diagnosis of urinary congenital abnormities / 中华放射学杂志

Objective To evaluate the imaging methods,characteristics,diagnostic value of multi- slice CT urography(MSCTU)in congenital abnormities of urinary system.Methods To collect 33 urinary congenital abnormities cases in three years and to analyses these MSCTU images.All examinations were performed with a multi-slice spiral CT scanner.The patients were intravenously injected with 90 ml of Iohexol 300 with a power injector at the rate of 3 ml/s.Nephrographic-phase images were obtained at 75 s after initiation of the injection of contrast material,the appropriate delay time is according to Kidney's enhancement extent and nephrohydrosis degree.Excretory-phase images were obtained through the abdomen and pelvis from 10 min.to 23 h after initiation of the injection of contrast material without abdominal compression.Excretory-phase images were transferred to the workstation and performed maximun intensity projection(MIP),multiplanar reconstruction(MPR),volume rendering(VR),and virtual cystoscopy (VC).Results The urinary congenital abnormities diagnosed by MSCTU in 33 cases,including 1 ectopic kidney,1 horseshoe kidney,1 renal malrotaion,2 supernumerary kidneys,2 ureteral valves,2 retrocaval ureters,4 congenital megaureters,6 ureteropelvic junction stenosis,9 pelviureteric duplication malformations and 5 bladder diverticula.The displaying rate of ureter was 91%(61/66).The scanning time of excretory-phase was less than 20 seconds in All cases.The average CT value of contrast media in displayed ureter lumens was 520 HU.The postprocessing images had clear,dimensional feature and It was satisfy the diagnosis.Conclusion MSCTU has clear,dimensional feature and has strong ability of displaying total anatomy shape and tiny pathology change of congenital abnormities in the urinary system.It is a very useful method for detecting the congenital abnormities in the urinary system.