Aiming at the subject characteristic of medical imaging,the authors summed up and analyzed the objective,thought and project in the reform of medical imaging experiment teaching in our school to probe into the direction of the reform of medical imaging experiment teaching and raise some thoughts about how to culture qualified students of medical imageology.

Objective To analyze the MRI features of chordoid meningioma (CM),and to compare with other meningiomas. Methods Clinical and MRI features of 7 patients with CM confirmed by pathology were analyzed retrospectively.Featrues of every MRI sequence were investigated qualitatively.Meanwhile normalized signal ratios of each sequence were analyzed furtherly,including normalized T1 weighted image intensity ratios (NT1 ),normalized T2 weighted image intensity ratios(NT2 ),normalized ADC ratios (NADC)and normalized T1 WI contast enhancement intensity ratios (NCE).Fisher ’s exact test and Dunnett T 3 test were employed to analyze the difference of CM and nonchordoid meningiomas (34 cases of WHO grade Ⅰ meningioma,1 6 cases of nonchordoid WHO grade Ⅱ meningioma,and 5 case of WHO grade Ⅲ meningioma).Results The CM showed hyperintensity on T2 WI and meanwhile other nonchordoid meningiomas demonstrated isointensity,hypointensity or slight hyperintensity on T2 WI.Evaluations of DWI revealed variable signal intensities of CM.But all 7 cases had no obvious restricted diffusion,and increased signal was seen on the ADC map in each patient.The solid parts of CM enhanced markedly after contrast agent injection.Quantitative indicators NT2 , NADC and NCE of CM were higher than other meningiomas(P <0.01),but NT1 showed no statistic difference between CM and other meningiomas (P =0.889).Whether there was cyst,necrosis,orflow void sign on T2 WI,and no matter with or without perifocal edema,dural tail sign and a broader base among meningiomas had no significance in differentiating CM and other meningiomas.Conclusion CM has typical MRI features.The tumors show hyperintensity on T2 WI,especially have no obvious restricted diffusion and enhance markedly after contrast.The measurement of NT2 ,NADC and NCE enables reliable preoperative prediction of the atypical histopathologic diagnosis.

Using the Medical Imaging Experimental Teaching Demonstration Center of Nanjing Medical University and related web site as a platform, we have established a case library and online learning system which fused medical imaging, pathology and anatomy images according to the human organ system. The system has achieved a“medical imaging”teaching real-time, diversified, systematic and clinical simulation technology. Medical students can perform image processing, simulate writing reports and discuss online using this system. Teachers can use the system to carry out teaching reform-problem-based learning (PBL), and the integration of teaching with horgan systems and case based curriculum.

Objective To evaluate the predictive value of MRI features in the diagnosis of placenta increta/percreta preoperative-ly.Methods We retrospectively reviewed MRI of 39 pregnant women who were suspected to have placenta increta/percreta by the ultrasound previously.1 7 patients were defined as placenta increta/percreta according to the surgical-pathological results,while 22 patients were defined without abnormal placentation.We assessed the presence or absence of the specialized MRI features of placenta increta/percreta.The binary logistic regression analysis was used to determine the valuable MRI findings for predictive of placenta increta/percreta.Results The tenting of the superior wall of bladder or the infiltration of adjacent organs were the most useful signs to predict placenta percreta,with the highest odds ratio (OR)value of 70,P =0.008.The low signal intensity bands on T2 WI and focally interrupted interface of placenta/myometrial were valuable signs to the predictive of placenta increta,with the OR value of 6.4 and 5.6 respectively according to the univariate analysis.On multivariate regression analysis,the low signal intensity bands on T2WI was independent predictive factor for placenta increta(OR 6.6,P =0.02),while the focally interrupted interface of placen-ta/myometrial was not independent factor (OR 3.1 6,P =0.1 75).Conclusion The most useful predictive MRI features for placenta increta/percreta are tenting of the superior wall of bladder and the infiltration of adjacent organs,followed by the low signal intensity on T2 WI.The focally interrupted interface of placenta/myometrial is useful factor.

Objective To study the baseline level of fraction anisotropy (FA) and the normal value of apparent diffusion coefficient (ADC) in deep white matter of preterm and its application.Methods From Oct.2010 to Dec.2013,in Department of Neonatology,Jiangsu Province Hospital,magnetic resonance imaging (MRI) (T1,T2) and diffusion tensor imaging (DTI) were done on 13 preterm infants of less than 37 weeks of corrected gestational age (CA),42 preterm infants of term-matched age,and 15 term infants.ADC and FA were measured in genu and splenium of corpus callosum (CC),anterior limb and posterior limb of internal capsule (IC).Results 1.The ADC values in genu,splenium,anterior limb of right IC,posterior limb of right IC,anterior limb of left IC,posterior limb of left IC in CA ＜ 37 weeks infants were higher than those in term-matched infants and in term infants.The ADC values in the 6 regions in term-matched infants and in term infants were significantly different with those in CA ＜ 37 weeks infant(F =5.559,5.775,21.948,19.462,30.586,15.452,all P ＜ 0.01).The differences of ADC values between CA ＜ 37 weeks infants and term-matched infants,between CA ＜37 weeks infants and term infants were significant(all P ＜0.05),except that in CC between CA ＜ 37 weeks infants and term-matched infants.2 The FA values in genu,splenium,anterior limb of right IC,posterior limb of right IC,anterior limb of left IC,posterior limb of left IC in CA ＜ 37 weeks infants were lower than those in term-matched infants and in term infants.The FA values in the 6 regions in term-matched infants and in term infants were significantly different from those in CA ＜ 37 weeks infants (F =9.835,7.500,4.811,11.430,8.674,12.666,all P ＜ 0.01).The differences of FA values between CA ＜ 37 weeks infants and term-matched infants (P ＜ 0.05),between CA ＜ 37 weeks infants and term infants were significant (all P ＜ 0.05).Conclusions The baseline values of FA and ADC in different deep white matters were obtained.As corrected gestational age of preterm babies' increased,FA values in brain white matter increased,while ADC values decreased.The myelination in most white matter of preterm infants at matched term can catch up with that of term infants.The diagnostic value of ADC and FA needs to be studied further.

Objective To explore the application value of susceptibility weighted imaging(SWI)in measuring brain iron deposition in the diagnosis and the assessment of Parkinson’s disease(PD).Methods Thirty cases with PD underwent head routine magnetic resonance imaging and SWI scanning.The unified PD rating scale(UPDRS)was used to assess the severity of PD.The phase values of substantia nigra (SN),red nucleus(RN),caudate nucleus (CA),globus pallidus(GP)and putamen (PUT)were measured manually on the phase map.The correlation between the phase values of the region of interest(ROI)and the UPDRS scores of PD was analyzed.Results There were no significant differences between the phase values of the less severe body side and those of the more severe body side (SN,P=0.120;RN, P=0.402;CA,P=0.196;GP,P=0.616;PUT,P =0.985).Significant negative correlations were found between the phase values of SN, CA,GP and the UPDRS Ⅲ scores,respectively (SN-UPDRS Ⅲ:r=-0.407,P =0.026;CA-UPDRS Ⅲ:r =-0.424,P =0.02;GP-UPDRS Ⅲ:r=-0.363,P =0.048).Significant negative correlation was found between the phase values of SN and the UPDRSⅤranks (r=-0.373 ,P =0.043 ),while the similar correlation was found between the phase values of CA and the UPDRSⅠ scores (r=-0.367,P =0.046)and the medium negative correlation was found between the phase values of GP and the gait disorder scores of UPDRS Ⅲ(r=-0.41 1,P =0.024).But no correlation was found between the phase values of other ROIs and the UPDRS scores. Conclusion SWI could quantitatively assess the brain iron deposition of the PD patient,which provided reference for clinical diagnosis and assessment of PD.

Objective To analyze CT and MRI characteristics of sellar cystic lesions.Methods Clinical and imaging data of 83 sellar cystic lesions were retrospectively analyzed.The location,size,number of the sac,thickness of the wall and some special signs,such as mural nodules,cavernous sinus invasion were observed.Results Totally 83 patients with sellar cystic lesions including cystic pituitary adenoma (n=33),craniopharyngioma (n=28),rathke cleft cyst (n-15),dermoid cyst (n =2),epidermoid cyst (n =2),arachnoid cyst (n =2) and pituitary abscess (n =1) were enrolled.The cystic pituitary adenoma and arachnoid cyst showed low signal on T1WI and high signal on T2WI.The signal of Rathke cleft cyst and craniopharyngioma displayed complex.Dermoid cysts,epidermoid cyst and pituitary abscess exhibited high signal on DWI.There were significant statistic differences of the size,number of the sac and the wall thickness among cystic pituitary adenomas,craniopharyngiomas and Rathke cleft cysts (all P＜0.05).Conclusion Observation of imaging features,including location,shape,signal intensity,characteristics of the capsule and some special signs can improve differential diagnosis of cystic lesion of sellar region.

Objective To investigate the diagnostic value of the texture analysis in differentiating adult pilocytic astrocytomas (PA)from hemangioblastomas(HB).Methods 22 adult patients with PA and 20 patients with HB which were confirmed by postoperative pathological were retrospectively reviewed.The conventional MRI features and texture parameters were analyzed.Eight texture parameters were extracted using run-length matrix(RLM),and the differences of texture parameters of the two groups were analyzed by independent-samples t test.Results The short run emphasis(SRE),grey-level non-uniformity(GLNU),run-length non-uniformity(RLNU),high grey-level run emphasis(HGRE)and short run high grey-level emphasis(SRHGE)were higher in adult PA than in HB.The long run emphasis(LRE),low grey-level run emphasis(LGRE)and short run low grey-level emphasis(SRLGE)were lower in adult PA than in HB.The eight texture parameters had significant differences between the two groups(P<0.05).Conclusion Texture analysis can provide reliably objective basis for differentiating adult PA from HB.