Wallerian degeneration of the corticospinal tracts is the anterograde degener-ation of distal axons and myelin caused by the upper motor neuron injury or axonal injury.Stroke is the most common cause of Wallerian degeneration of the corticospinal tracts. Conventional magnetic resonance imaging (MRI) of Wallerian degeneration of the corticospinal tracts is a linear abnormal signal that connects the original lesion along the corticospinal tracts, but the conventional MRI signal does not reveal Wallerian degeneration until 4 weeks after stroke. Diffusion tensor imaging (DTI) detects early Wallerian degeneration of the corticospinal tracts, and dynamically observes the process of pathological changes from early subacute stage to chronic stage. 1his article reviews Wallerian degeneration of the corticospinal tracts on DTI after stroke, especially the effect in early Wallerian degeneration, as well as the values in predicting prognosis and late rehabilitation in patients with stroke.

Objective To evaluate the accuracy of MR diffusion weighted imaging (DWI) in the diagnosis of hyperacute cerebral infarction. Methods Twenty one patients with onset of strokelike symptoms underwent conventional MRI and DWI within 6 hours. Results DWI indicated cerebral infarction in 16 patients, all of whom had a final diagnosis of acute stroke. DWI was negative in 5 patients, all of whom had a final diagnosis of TIA. The abnormality seen at DWI was confirmed with follow up study. DWI had a sensitivity of 100% and a specificity of 100% in the diagnosis of hyperacute cerebral infarction, and conventional MRI interpretation yielded a sensitivity and specificity of 25% and 100%, respectively. Conclusion DWI is highly accurate in diagnosing hyperacute cerebral infarction and is superior to conventional MRI.

Objective To analyze CT and MR imaging features of dysembryoplastic neuroepithelial tumor(DNT),so that to improve its diagnostic accuracy.Methods CT and MRI fidnings of DNT in 10 cases proved surgically and pathologically were retrospectively reviewed.Results All lesions were located in the super-tentorial gray matter regions or involved the cererbral certex mainly.The lesions were round,lobular,triangular or irregular pseudocystic masses with definite borders mostly.The lesions were hypointense on T_1WI and hyperintense on T_2WI.On fluid attenuated inversion recovery weighted images,the hyperintense "ring sign" and septa of the lesions were seen.On diffuse-weighted images(DWI),the lesions were hypointense or slight hypointense.On MR spectroscopy,NAA of the lesions slightly decreased.There were no peripheral edema and mass effect with well-demarcated.7 lesions had no enhancement and 3 lesions had slight unhomogeneous enhancement after administration of contrast medium.The lesions in 2 cases on plain CT showed low attenuation and one had calcification inside the lesion.Conclusion DNTs are of typical neuroradiologic features,that may be helpful for the diagnosis of which preoperatively.

Objective To study the manifestations of MR of the tumor in jugular foramen area(JFA) and its diagnostic values.Methods 13 cases of tumors confirmed by pathology in JFA were reported,and the characteristics of MR of different kinds of tumor were analysed.Results There were its own MRI manifestations of different tumors in JFA,and the localizing and qualitative diagnosis of these tumors can be accurately made by MRI.Conclusion MRI is of very important diagnostic values in detecting the tumors in JFA.

Objective To evaluate the capability of Turbo inversion recovery magnitude (TIRM) magnetic resonance neurography (MRN) in the diagnosie of sacral plexus injury by comparing MRN findings with surgical results.Methods Ten patients with sacral plexus injury confirmed surgically underwent conventional T1WI,T2WI,TIRM and coronal TIRM MRN before operations from June,2011 to December,2012.The MRI data and surgical data were analyzed retrospectively to observe nerve injury.Results The coronal TIRM MRN images displayed 93 trunks of sacral plexus,of which 37 were confirmed injury by operation.The MRI findings were as follows:6 trunks involved continuous nerves,but with thickening and blurred margin,as well as abnormal high signal intensity;22 trunks were continuous,but with distortion,stiffness and adhesion accompanied by heterogeneous signal intensity and structural disorder;3 trunks showed complete loss of continuity,absence of normal signal,accompanied by retraction;and 3 trunks involved formation of traumatic neurofibroma.The coincidence of injured nerve trunks diagnosed by MRN with surgical findings amounts to 81.08％ (30/37).Conclusion MR with coronal TIRM imaging is effective in the diagnosis and depiction of sacral plexus injury,therefore it can be used as conventional sequence in sacral plexus examination to detect sacral plexus avulsion.

Objective To explore the comparative application of phase and diaphragmatic navigation in three-dimensional magnetic resonance cholangiopancreatography(3D-MRCP)thin-layer scanning in elderly patients.Methods A total of 180 elderly patients were scanned by phase and diaphragmatic navigation via Siemens Aera1.5T superconducting MR scanner.The acquired images were reconstructed by 3D reconstruction.The anatomical structure,image quality and disease diagnosis were compared between the phase and diaphragmatic navigation groups.Results In liver of anatomy,the liver of primary bile duct,the superior,middle and inferior extrahepatic bile duct and the gallbladder could be well displayed,and the difference was not statistically significant between the two groups(P＞0.05).The display of pancreatic duct and the liver of secondary bile duct of diaphragmatic navigation was significantly better than those of phase navigation(P＜0.05).In terms of image quality,the excellent rate of diaphragmatic navigation was significantly higher than that of phase navigation,and the difference was statistically significant(P＜0.05).There were no statistically significant differences in the detection rate of pancreatobiliary system diseases,the diagnostic rate of cholelithiasis,common bile duct stones,common bile duct dilatation and pancreatic duct dilatation between the two groups(P＞0.05).Conclusion Diaphragmatic navigation is signifi-cantly better than phase navigation in the display of the anatomical structure of the pancreatic duct,the liver of secondary bile duct,and the excellent rate of image quality.Diaphragmatic navigation is more suitable for thin-layer 3D-MRCP scanning in elderly patients.

OBJECTIVETo estimate the value of blastocyst culture for preimplantation genetic diagnosis (PGD).

METHODSDay 3 embryos were biopsied and analyzed with fluorescence in situ hybridization (FISH) technique. Embryos with normal FISH results were cultured into blastocysts, and the ones with better morphology scores were transferred. Fourteen embryos with abnormal FISH results were cultured into blastocysts. Part of the cells taken from the blastocysts were amplified by whole genomic amplification (WGA) and assessed by array-based comparative genomic hybridization (array-CGH) analysis.

RESULTSSix blastocysts with normal FISH results were transferred in 5 cycles. Four healthy babies of 3 cycles were delivered. Another one was a singleton pregnancy but with embryo growth arrest, whose villus karyotype was normal. Fourteen embryos with abnormal FISH results were cultured into blastocysts and analyzed by array-CGH. Six blastocysts were normal by array-CGH.

CONCLUSIONFISH combined with blastocyst culture may further ensure the accuracy of PGD result. Detection at the blastocyst stage can avoid false positive results and mosaic interferences on Day 3 stage and are therefore more authentic.

Adult ; Blastocyst ; cytology ; Comparative Genomic Hybridization ; methods ; Embryo Transfer ; Female ; Genetic Diseases, Inborn ; diagnosis ; embryology ; genetics ; prevention & control ; Humans ; In Situ Hybridization, Fluorescence ; methods ; Male ; Pregnancy ; Preimplantation Diagnosis ; methods

Objective To comprehensively analyze the clinical outcomes of total cavopulmonary connection (TCPC) in the treatment of functional single ventricle combined with heterotaxy syndrome (HS). Methods A retrospective analysis was conducted on the patients with functional single ventricle and HS who underwent TCPC (a HS group) in Guangdong Provincial People's Hospital between 2004 and 2021. The analysis focused on postoperative complications, long-term survival rates, and identifying factors associated with patient survival. Early and late postoperative outcomes were compared with matched non-HS patients (a non-HS group). Results Before propensity score matching, 55 patients were collected in the HS group, including 42 males and 13 females, with a median age of 6.0 (4.2, 11.8) years and a median weight of 17.0 (14.2, 28.8) kg. Among the patients, there were 53 patients of right atrial isomerism and 2 patients of left atrial isomerism. Eight patients underwent TCPC in one stage. TCPC procedures included extracardiac conduit (n=39), intracardiac-extracardiac conduit (n=14), and direct cavopulmonary connection (n=2). Postoperative complications included infections in 27 patients, liver function damage in 19 patients, and acute kidney injury in 11 patients. There were 5 early deaths. The median follow-up time was 94.7 (64.3, 129.8) months. The 1-year, 5-year, and 10-year survival rates were 87.2%, 85.3%, and 74.3%, respectively. After propensity score matching, there were 45 patients in the HS group and 81 patients in the non-HS group. Compared to the non-HS group, those with HS had longer surgical and mechanical ventilation time, higher infection rates (P<0.05), and a 12.9% lower 10-year survival rate. Multivariate Cox regression analysis identified asplenia was a risk factor for mortality (HR=8.98, 95%CI 1.86-43.34, P=0.006). Conclusion Compared to non-HS patients, patients with HS have lower survival rates after TCPC, and asplenia is an independent risk factor for the survival of these patients.