Objective: To investigate the value of MR unenhancement and dynamic enhancement scans for distinguishing non-hypervascular pancreatic neuroendocrine tumor (PNET) from pancreatic ductal adenocarcinoma (PDAC). Methods: Thirty five patients (45 lesions) with pathologically confirmed PNETs and 52 patients (53 lesions) with PDACs were retrospectively analyzed before surgery. All patients underwent MR unenhanced and dynamic enhanced scans (including arterial, venous and delayed phase). Based on arterial enhancement, PNETs were divided into hypervascular and non-hypervascular lesions. The morphologic characteristics (including location, size, quantity, margin and signal intensity) and enhancement patterns of non-hypervascular PNETs and PDACs were evaluated. Involvement of the pancreatic duct and bile duct, vascular invasion, peripancreatic infiltration and other organs metastasis were observed. Independent sample ttest was used to compare signal intensity ratio of nonhypervascular PNET and PDAC. Chi-square test was used to compare MRI characteristic and secondary signs. Results: PNET included 20 hypervascular and 25 nonhypervascular lesions. Enhancement degree of non-hypervascular PNET was higher than PDAC in the arterial, venous and delayed phase (P<0.01). Non-hypervascular PNET showed significantly higher frequencies (P<0.01) of venous hyper-or isoenhancement (20/25), delayed hyper-or isoenhancement (23/25) and a well-defined margin (17/25), but lower frequencies of ductal stricture and dilatation (P<0.01), pancreas atrophy (P<0.05), bile duct stricture (2/25), peripancreatic infiltration (8/25, P<0.01) and vascular invasion (8/25, P<0.05), when compared with PDAC. Conclusion A well-defined margin, hyper-or isoenhancement in the venous and delayed phase,and without ductal dilatation and pancreas atrophy are more common in non-hypervascular PNET, which may be distinguished from PDAC.

Objective To investigate the relationship between the MR findings of lumbar elements and chronic low back pain(CLBP).Methods The patients underwent lumbar MRI examinations and sent for a questionnaires of low back pain (LBP).Among them,139 patients whose questionnaires illustrated with CLBP were enrolled.The enrolled patients included 68 patients with nerve roots compression and 71 patients without.Meanwhile,198 hospital staffs underwent lumbar MRI examinations and were sentfor a LBP questionnaire.Among them,62 patients without LBP and nerve roots compression were enrolled.Categorical regression was used to analyze the relationship between MR findings and CLBP.The MR findings iucluded nerve roots compression,average disk degeneration scores(ADD),high-intensity zones (HIZ),Schmorlnodes,Modic Ⅰ change,average facet joints degeneration scores(AZZ),facet joint effusion,high T2 signal in interspinous ligament and subcutaneousparaspinal muscles edema.The regression model was used to analyze the MR imaging and CLBP.Results The regression model was statistically significant (F=9.478,P＜0.01).All predictors yielded an adjusted value was 0.446.Among all predictors,nerve roots compression,ADD,AZZ,subcutaneous or paraspinal muscles edema were statistically associated with the VAS degree (P＜0.05).The sum of the importance of the four predictors above was 0.983.The quantification of predicted VAS degree increased as ADD level increased.The quantification of predicted VAS degree increased to the top at the 2 AZZ level and then decreased.Nerve roots compression and Subcutaneous or paraspinal muscles edema yielded higher quantification of predicted VAS degree level.Conclusion ADD,AZZ,subcutaneousparaspinal muscles edema were probably associated with CLBP degree after adjusting for nerve roots compression.

Objective To evaluate contrast-enhanced MRI sequence for diagnosing cholangiocarcinoma.Methods Cholangiocarcinoma was confirmed by surgery and pathology in 17 cases,all underwent preoperative CT and MRI T1-VIBE scan with contrast-enhancement sequence.We retrospectively analyzed imaging signs in two scan methods,including lesion position,number,size,enhancement degree,expansion degree of bile duct,invasion of adjacent artery and portal vein,and portal vein tumor thrombosis.The differences on detecting lesions between two methods were compared.Results The contrast to noise ratio (CNR) between tumor and liver tissue in MRI T1-VIBE images was obviously superior to that in CT images.Peripheral lesion boundary in T1-VIBE enhanced images was clearer than CT.One hemorrhage lesion was shown in T1-VIBE images,and tumor thrombosis was visible in the left branch of portal vein in 1 case.Bile duct wall lesions in T1-VIBE enhanced images was more evident than CT in hilar cholangiocarcinoma and extrahepatic cholangiocarcinoma.The VIBE enhanced images find more lesions in 9 out of 11 multiple focus cases,compared with CT images.Conclusions Contrast-enhanced MRI T1-VIBE sequence can give more comprehensive and clear evaluation on cholangiocarcinoma,and has important clinical diagnostic values.

ObjectiveTo observe and analyze the synapses developing process of newly generated connections of autologus activated Schwann cells (AASCs) in combination with fetal spinal cord cell suspension(FSCS) in the surrounding area of the spinal cord injury site.MethodsA total of 42 Wistar rats underwent unilateral ligation of the saphenous nerve.The portion of nerve tissues distal to the ligation site were harvested 1 week after operation.AASCs were isolated,cultured and purified.Spinal cord injury model produced in 42 Wistar rats on T7 by modified Allen impact method.Three days after injury,20 μl FSCS with a density of 1×105/μl prepared from pregnant rats (El4) in combination with AASCs were injected into the epicenter of the traumatized cavity.Animals were sacrificed at 2,4,6,8,10,12 weeks post transplantation.Light and electronmicroscopic studies as well as immunohistochemical assay were carried out to evaluate the graft survival,its differentation and integration with the host.ResultsIn the transplantation area,AASCs showed good growth and differentiation,and glial scarring surrounding the lesions was less.The neuroblast stretched out the terminal endings 4 weeks after implantation,followed by the presenting of the pre- and post-synaptic membrane.Eight weeks post transplantation,the dense or developed projections were observed in the pre- and post-synaptic membrane,the high electron dense substance full filled the synaptic cleft.All the spherical cleat vesicles,granular vesicles,elliptical vesicles and flattened-f type vesicles were discovered under the electron microscope.Ten weeks after injury,the axosomatic,dendrosomatic,dendro-dendritic,axoaxonic,and dendro-axonic synapses coexisted.Light microscopy showed that the graft cell grew gradually.Immunohistochemical assay showed that NF,5-HT,CGRP and GFAP positive fibers were in the graft.Synapses,glia fibers and blood brain barrier integrated each other.Conclusion1) The transplanted FSCS combined with AASCs can develop mature synapses with miscellaneous synaptic vesicles in the acute injured spinal cord.2) Co-existing indicate the possibility of synaptic connection between FSCS and host.

Objective To introduce the surgical strategy of enlarged laminectomy (with partial facet joint dissection to expose the nerve root), and to discuss its benefit for cervical ossification of the posterior longitudinal ligament(OPLL) with myelopathy. Methods Totally 82 patients with cervical OPLL were treated by enlarged laminectomy from January 1998 to December 2005. There were 47 males and 35 females, with an average age of 57 years (ranged, 39-84 years). Among them, there were 31 cases of the solitary type, 40 cases of the continuous type, and 11 cases of the mixed type. JOA scoring system and the visual analogue scale (VAS) scoring were applied to evaluate the neurological function and neck/shoulder pain respectively.Ishihara method was employed to measure cervical curvature index(CCI). The degree of spinal cord backward expanding and displacement were calculated in MR1. Results The mean decompression length was 5.2 (4-6) segments. The mean follow-up duration was 41 months (ranged, 13-58 months). JOA score has improved from 10.9(7-15) preoperatively to 13.9(11-17) postoperatively (t=14.65, P＜0.01). The excellent and good rate was 98.7%. The palsy of C5 nerve root occurred in only 2 patients, both recovered after surgery. Zhe mean postoperative VAS score was 1.4(1-3), comparing with the preoperative score of 5.3 (4-6). The pain in neck/shoulder was alleviated obviously (t=15.46, P＜0.01 ). CCI decreased from 18.8% to 10.5%(t=5.03, P＜0.01 ),but did not follow by neuron function deterioration. MRI indicated that the cross-sectional area at the level of maximum compression of the dural sac increased from 85.4 mm2 preoperatively to 153.8 mm2 postoperatively (t=16.33, P＜0.01), and the mean spinal cord posterior shift was 6.2 mm (t=15.35, P＜0.01). Conclusion The enlarged laminectomy is proved to be effective in treating cervical OPLL, in terms of significant posterior shift of the spinal cord, relief of cervical/shoulder pain, lower rate of the palsy of C5 nerve root, with no recurrence of spinal cord compression symptom.

Objective To evaluate the surgical strategy of decompression via posterior-anterior approach and anterior fixation in treatment fracture-dislocation of the lower cervical spine with bilateral facet joints dislocation. Methods This study retrospectively reviewed 37 cases of lower cervical spine fracture with bilateral joints dislocation. There were 21 males and 16 females with an average age of 42 years (19-58). Distraction-flexion stage 3(DFS 3) were found in 24 cases and DFS 4 in 13 cases. All the cases were diagnosed by X-ray, CT and MRI and confirmed during the surgery. Decompression via posterior-anterior approach and anterior fixation had been adapted as the surgical strategy. The NASCIS and IMSOP standard were applied to definite the level of cervical spinal cord injury. The ASIA grading was used for evaluation the spinal cord function and the recovery rate. The X-ray and CT were used to observe reduction and bone fusion. Results The mean operative time was (4.5:±0.5) h, and the mean amount of blood loss was 360 ml (200-500 ml). All the incision healed. The two segments fixation was used in 23 cases, 3 segments fixation in 13 cases, and 4 segments fixation in 1 case. The mean follow-up period was 32 months (16-45 months).Postoperative X-ray and CT showed that bone fusion was achieved in all patients within 4-8 months, without graft displacement, or failure of implants. Spinal cord function did not aggravate, and sensory recovery ranged from 7 to 20 levels (averaged, 12.7). The ASIA grade were improved with an average of one grade. Conclusion To treat fracture-dislocation of the lower cervical spine with bilateral facet joints dislocation, the posterlor-anterior approach and anterior fixation/fusion was benefit to preservation the cervical spinal cord function and reconstruction biomechanical stability of the cervical spine.

Objective To explore the surgical strategies of thoracic spinal stenosis with dural ossification. Methods One-hundred and eight patients with thoracic spinal stenosis were treated. Dural ossification was found in 29 cases during operation from January 2004 to June 2008. There were 19 males and 10females, with an average age of 56.4 years (42-74 years). The course of disease was 13 months (2-48months). The lesion was located in T1-T4 in 4 cases, T5-T8 in 5 cases, and T9-T12 in 20 cases. All the patients were treated by posterior lamina resection. Both ossificated dural and ossificated yellow ligament were resected in 16 patients. Decompression was performed with partial ossification remaining on dural surface in 13 cases. JOA score was used to evaluate the outcomes 1, 3 and 12 months after operation. Results The average operation time was 140 min, and average bleeding was 300 ml. Dural incisions were repaired with a wound drainage in 11 cases. Seven cases appeared cerebrospinal fluid leakage which healed in 3-5 days.Dural incisions were not repaired without wound drainage in 5 cases. Cerebrospinal fluid leakage occurred in these cases healed in 5-7 days. Thirteen cases treated with floating method did not appear cerebrospinal fluid leakage. All patients did not undergo subarachnoid infection and the aggravation of original nervous system symptoms. According to JOA score, all patients were evaluated as excellent in 22 cases, good in 5 and fair in 2 cases, and excellent and good rate was 93%. Conclusion For thoracic spinal stenosis with dural ossification, resection of both ossificated dural and ossificated yellow ligament and complete decompression with partial ossification remaining on dural surface is safe and reliable. Dural ossification does not influence the prognosis, but increase operative difficulty and risk.

Objective To explore the clinical characteristics and risk factors of re-fracture in patients suffering from osteoporosis-related fractures as well as effective interventions.Methods From January 2006 to January 2008,a total of 273 patients with osteoporosis-related fracture were entered in the study,including out-patients and in-patients who were over 50 years old.The patients were divided into fracture group(n=225)and re-fracture group(n=48).The re-fracture rate was followed up for 2 years,during which 11 patients developed re-fracture.General data including age and sex,fracture types,femoral neck bone mineral density(BMD)T-scores tested by dual-energy X-rays absorptiometry(DEXA),Charlson index,timeinterval between two fractures as well as mobility skill assessment were collected and analyzed.Results The average age at the first fracture was 67.7±8.5 years vs.72.7±9.5 years for the re-fracture cases.Female accounted for 70.2% of the fracture group and 77.1% of the re-fracture group.The most common re-fracture type was vertebral fracture for the first time and femoral neck fracture for the second time during the followup.Risk factors for a second fracture in osteoporotic fractures patients include age(＞75 years,HR=1.23; ＞85years,HR=1.68),female sex(HR=1.36),prior vertebral fractures(HR=1.62),prior hip fractures(HR=1.27),BMD T-score＜-3.5(HR=1.38)and weakened motor skills(HR=1.27).The refracture rate in osteoporosis-related fractures was 4.9% followed up for 2 years.The second fracture happened 3.7 years after the first one on average.Conclusion The risks of second fracture among patients with initial brittle fracture are substantial.Mobility skill assessment is an important risk factor for osteoporosis fractures recurrence.There is adequate time between fracture and re-fracture for effective interventions to prevent or reduce the risks of refracture,especially for the old women with a vertebral or hip fracture.Medication,motor function rehabilitation and fall-down prevention training would be helpful.

Objective To describe the pathological unit and octagonal en bloc resection for the treatment of ossification ligamentum flavum(OLF)in thoracic spine with spondylotic myelopathy.Methods Ninety-five patients from January 2002 to January 2007 were diagnosed as thoracic OLF,61 males and 34 females with an average age of 53.9 years(range,31-78 years).There were upper thoracic spine OLF in 32 cases,middle thoracic spine OLF in 24 cases and lower thoracic spine OLF in 39 cases.Single-segment OLF was found in 53 cases,double segments OLF was found in 38 cases and three segments OLF was found in 4 cases.CT scan multiplanar co-localized reconstruction was employed to detect the structure of spine with OLF.The Japanese Orthopaedic Association(JOA)lower limb motor function score,sphincter function score and motor function improvement rate were used to evaluate the outcomes.Results CT scan was engaged to observe 141 OLF pathological unite.The OLF pathology unit was defined as all the spine structures between the extension lines of the lower margin of the OLF two adjacent pedicles.Each OLF associates with an OLF pathology unit.The mean follow up duration was 38.3 months(range,24-60 months).Among 86 patients with sensations disturbance before operation,67 totally recovered and 19 relieved after operation.Trunk restrictions in 69 cases before operation were completely recovered after operation.Postoperative JOA sphincter function score was 2.651±0.334,comparing with preoperation score(2.262±0.561),and the difference was statistically significant.Postoperative JOA motor function score was 3.694±0.429,which was significantly increased than preoperative score 1.539±0.873,and motor function recovery rate was 87.57%.There was excellent in 71 cases,good in 17 cases and fair in 5 cases.The excellent and good rate was 94.74%.Conclusion The octagonal en block resection is relative safe for treatment thoracic OLF with myelopathy.Pathological unit of OLF in thoracic spine is more accurate to summarize the pathological contents and features of the OLF and its adjacent structure.

Objective To study the clinical features and surgical strategies of thoracic spinal stenosis caused by ossification of posterior longitudinal ligament(OPLL).Methods From January 2004 to March 2009,21 cases of thoracic spinal stenosis casued by OPLL,including 13 males and 8 females,received surgical treatments.Those cases aged from 34 to 71 years,with an average of 51.2 years old.The courses of disease were from 2 to 50 months,averaged 11 months.The lesions located in upper thoracic(T1-T4)for 4 cases,in middle thoracic(T5-T8)for 7 cases,in lower thoracic(T9-T12)for 10 cases.Nine cases were associated with ossification of ligamentum flavum(OLF),and 8 cases combined with cervical OPLL.Eleven cases received laminectomy and 10 cases received anterolateral decompression.Results The operation time was 90 to 240 min for posterior laminectomy with an average of 140 min,and 110 to 360 min for anterolateral decompression with an average of 240 min.All cases had no worse postoperative symptoms,neurological complications,subarachnoid cavity or wound infection.Japanese Orthopaedic Association(JOA)score was 8 to 15 with an average of 9.17±1.63 in 6 months after surgery.Nerve function improvement was excellent for 8 cases,good for 6 cases,fair for 5 cases and poor for 2 cases.The excellent and good rate was 66.7%.JOA score was 8-15,averaged 10.23±1.64,in 12 months after surgery.Nerve function improvement was excellent for 8 cases,good for 7 cases,fair for 4 cases,and poor for 2 cases.The excellent and good rate was 71.4%.Conclusion Thoracic spinal stenosis result from OPLL,which often combine with cervical OPLL and OLF,often show multiple manifestations.Posterior laminectomy and anterolateral decompression are suitable for those conditions.