Objective To study the imaging findings of atypical thymoma.Methods 16 patients with atypical thymomas confirmed by pathology were involved in this study.Results In 16 cases,the all tumors appeared as soft tissue masses in anterior mediastinum,other imaging findings included lobulated sign in 12,calcification with in the tumors in 9,directly invasion to adjacent fatty tissue in 13 and mediastinum pleural and anterior chest wall in 7.The ipsilateral mediastinum pleural planting in 8,vascular involvement in 7 and pleural effusion in 6,pericardium effusion in 3 were showed.The tumors with smooth margins and clear surrounding fatty tissue were seen in 3,that were really simulating the benign thymoma.Conclusion Atypical thymoma are of certain imaging characteristics.

Objective To evaluate the clinical application value of multislice spiral CT (MSCT) in diagnosis andclinical treatment of the chronic suppurative otitis media(CSOM). Methods Multislice spiral CT with direct axial plane and saggitalmultiplanar reformation(MPR) were performed in 61 cases including 76 ears.The results from those images were comparedwith that of operations. Results The sagittal MPR images preferably could delineate the anatomical details of the temporal bone and theadjacent relationship,and could display the tympanicand mastoid segment of the facial nerve,sigmoid sinus plate and the glomusjugular better.On the sagittal MPR images,the disruption of the ossicular chain and bony erosion in the tympanic cavity and antrum weredisplayed in 38 ears.The destruction of the facial nerve canal was severe in the type of cholesteatoma compared with the type of granuloma of chronic suppurative otitis media.The congenital abnormities were showed in 8 ears of the sigmoid sinus plate and 2 ears of the glomus jugular.Conclusion CT sagittal MPR images are of significant clinical value in showing the degree and location of destruction of the canal of facial nerve , and the relation between around structures in chronic suppurative otitis media.

Objective To study the value of MRI sequence and MRA in the diagnosis of reversible cerebral vasoconstriction syn-drome (RCVS).Methods MRI and MRA of 5 patients with RCVS were reviewed retrospectively.Abnormal distribution,morpholo-gy,signal intensity of the affected arteries and complication of RCVS on MRI and MRA were analyzed.Results All patients showed multifocal segmental vasoconstriction and dilatation of cerebral arteries on MRA,which sometimes was described as “string and beads”.There were 4 patients with cerebral parenchyma lesions,in which posterior reversible encephalopathy syndrome was showed in one case,cortical subarachnoid hemorrhage in one case,and watershed infarcts in 3 cases.Five patients recovered after 3 months. Conclusion MRI and MRA can clearly show cerebrovascular morphology and observe parenchymal secondary lesions,which have an important guiding significance for clinical treatment and prognosis assessment.

Objective To investigate the MSCT characteristics of peritoneal pseudomyxoma. Methods CT findings of peritoneal pseudomyxoma proved by surgery and pathology in 11 cases were retrospectively analyzed. Results On MSCT,the peritoneal pseud-omyxomas were irregular intraperitoneal cystic-solid masses, the CT attenuation was 18.5 ～ 27.6 HU, there were scallop-like, wavy and nodule-like indentations on the liver and/or spleen surface,large amount of mucinous ascites within abdominal, pelvic an-domentum cavity , thickening of peritoneum. On post-contrast administration , mild enhancement of peritoneum,cystic wall and omentum could be revealed. Conclusion MSCT examination has important value in diagnosis and differential diagnosis of peritoneal pseudomyxomas

Objective To explore the application value of 3.0T MR diffusion tensor imaging (DTI)in 3D reconstruction of the knee peripheral nerve.Methods DTI with 25 motion probing gradients (MPGs)was performed on the left knee in 22 healthy young volunteers;By choosing the original images scaned in the vertical direction,three post-processing methods including maximum intensity proj ection (MIP),volume rendering (VR)and diffusion tensor tractography (DTT)were used.Two radiologists evaluated these images visually.For the same nerve,MIP,VR and DTT were compared using Friedman test.Intraclass correlation coefficient (ICC )analysis was used to compare the correlation among the three imaging methods.Score consistency between two observers was calculated by using the Kappa statistic.Results For the same nerve,there was no significant statistical difference for the MIP,VR and DTT imaging quality scores(P>0.05).The I CC value and the k value were 0.718-0.856,0.668-0.705,respectively.Conclusion Stereoscopic and clear displaying the tibial nerve/the common peroneal nerve in the knee can be achieved by using MIP,VR and DTT post-processing methods based on DTI original images.The reconstruction of MIP,VR is simple and efficient,in which the objectivity is better than DTT.The reconstruction of MIP,VR can be used as effective preview methods before the DTT reconstruction with complexity and strong subjective dependence.

Objective:To explore the application values of arterial transit artifact (ATA) showed by 3D arterial spin labeling (3D-ASL) combined with hyperintense vessel sign (HVS) showed by T2-magnetic resonance fluid attenuation inversion recovery (T2-FLAIR) in evaluating collateral circulation and clinical prognoses in patients with acute ischemic stroke (AIS).Methods:One hundred and one AIS patients admitted to our hospital from September 2017 to November 2019 were included in the study. According to the degrees of vascular stenosis, these patients were divided into middle cerebral artery (MCA) positive group (stenosis degree≥50%, n=60) and MCA negative group (stenosis degree<50%, n=41); according to whether there was ATA, the MCA-positive patients were divided into ATA(+) group ( n=33) and ATA(-) group ( n=27). The cerebral blood flow (CBF) of the ischemic penumbra (IP) and National Institute of Health stroke scale (NIHSS) scores at admission and at discharge in patients from different groups were recorded; the relative CBF (rCBF) and drop degrees of NIHSS scores at discharge were calculated; a comparative analysis of the relations of ATA and HVS with clinical prognoses was performed. Results:There were significant differences in HVS grading, rCBF, NIHSS scores at admission and at discharge and drop degrees of NIHSS scores at discharge between MCA positive group and MCA negative group ( P<0.05). Among the 60 patients from MCA-positive group, 16 were classified as HVS grading 0, 14 as HVS grading I, 17 as HVS grading II, and 13 as HVS grading III; there were statistical differences in rCBF and drop degrees of NIHSS scores at discharge among patients with different HVS grading ( P<0.05); the higher the HVS grading was, the greater the decrease of rCBF and drop degrees of NIHSS scores were. Spearman correlation analysis showed that there was a high positive correlation between HVS grading and rCBF ( r s=0.808, P=0.000), and a moderate positive correlation between HVS grading and drop degrees of NIHSS scores at discharge ( r s=0.737, P=0.000). Patients in the ATA(+) group had significantly greater decrease of rCBF and drop degrees of NIHSS scores, and significantly lower NIHSS scores at discharge as compared with patients from the ATA(-) group ( P<0.05). Spearman correlation analysis showed that ATA had moderate positive correlations with rCBF and drop degrees of NIHSS scores ( r s=0.403, P=0.001; r s=0.550, P=0.000); there was a highly positive correlation between rCBF and drop degrees of NIHSS scores ( r s=0.827, P=0.000). Receiver operating characteristic curve showed that the sensitivities of ATA and HVS to assess cerebral blood perfusion changes were 83.3% and 66.7%, and the specificities were 52.1% and 89.6%, respectively; the combined sensitivity of the two was 83.3% and the specificity was 64.6%. Conclusion:HVS combined with ATA can effectively evaluate the perfusion in IP region and prognoses of AIS patients.

Objective To investigate the clinical manifestation and imaging features of diabetic striatopathy(DS).Methods A retrospective analysis was conducted on the clinical,laboratory,and imaging data of 8 patients with DS,which was then summarized in conjunction with relevant literature.Results Random blood glucose(8.39-24.80 mmol/L)and glycated hemoglobin(HbA1c)(9.0%-21.50%)were elevated in 8 patients.One case had positive urine ketone bodies(++),while 7 cases had negative urine ketone bodies(-).Hemichorea was present in 7 cases,while 1 case did not exhibit hemichorea.A total of 7 cases showed unilateral striatum T1WI hyperintensity on MRI,and 8 cases showed iso/hyper-density on CT scans.Following blood glucose control and other related treatments,involuntary movement disappeared in 2 cases,and symptoms improved in 5 cases.Conclusion DS mainly occurs in diabetic patients with poorly controlled blood glucose,presenting with typical clinical manifestation and neuroimaging features.It manifests exclusively in the contralateral striatum of the affected limb.The diagnosis should be based on a combination of clinical,laboratory,and imaging findings to prevent missed or misdiagnoses.