To improve the teaching effect of head and neck imaging and to further train most high quality talents majoring in head and neck imaging,some teaching experiences were summarized in this article. First,the‘step teaching method’was put forward for students to master the head and neck imag-ing anatomy. Second,students were taught to familiarize the imaging modalities of head and neck and to know the optimal imaging pathway and protocol of this region. Last, students were taught to develop good ideas for analyzing imaging of head and neck disease including localization diagnosis and characteri-zation diagnosis. Additionally,teaching supervision system,including taking notes,attending morning shifts,following up patients and reading literatures,was established for students.

Main problems for radiology teaching have always been less lectures and weaker imaging knowledge and lower interest of students in traditional Chinese medicine universities.Though "flipped classroom" has become the focus of education reform,and PACS system has become a platform in imaging diagnosis,it is rare to combine the two methods in radiology teaching.This paper mainly introduces features of flipped classroom and PACS system,analyzes the feasibility of combing the two teaching methods,and puts forward the teaching conception.Procedures are as follows.Before class,teachers design teaching objective,prepare teaching material and make the list;students study before class in different groups.During class,students exchange their ideas,start inter-group discussion and use the PACS system for case studies;teachers instruct the key and difficult point.After class,the comprehensive evaluation is conducted.The combining teaching hopes to promote students' learning interest,improve their learning effectiveness,cultivate their self-study ability and broaden their clinical minds.At the same time,this method also can provide experience for radiological teaching reform.

Objective To study the feasibility and value of magnetic resonance diffusion tensor imaging (DTI) to monitor non?arteritic anterior ischemic optic neuropathy (NAION). Methods Thirty eight NAION patients (56 eyes) were divided into acute period in 17 eyes, progressive period in 16 eyes and chronic period in 23 eyes at the base of onset time. According to matching principle, 56 eyes in 38 normal controls (NCs) were enrolled. All the patients and NCs underwent MR and DTI scan. The raw data were processed by two experienced radiologists, mean diffusivity (MD), axial diffusivities (λ//), radial diffusivities (λ┴), fractional anisotropy (FA) and Length value were got. The independent sample t test was used for the parameter values between the NAION group and the NCs group. A single factor variance analysis was used to compare the parameters among different stages of NAION group. Results Compared to the NCs group, the values of FA and Length in NAION group were reduced [0.20±0.11 vs 0.31±0.12, (5.85±0.92) vs (65.11± 6.89) mm], and the differences were statistically significant (t=-4.28,-5.25;P<0.05). The values of MD andλ┴were increased [(0.16±0.04)×10-3 vs (0.10±0.04)×10-3 mm2/s, (0.16±0.05)×10-3 vs (0.09±0.03)×10-3 mm2/s] in NAION group and the differences were statistically significant (t=6.83, 7.10;P<0.05). The value of FA and Length in acute period, progressive period and chronic period of the NAION group decreased differently compared to the NCs group. At the same time, the value of MD value and λ┴in the three periods of the NAION group increased compared to the NCs groupand the differences were statistically significant (P<0.05). The value of FA between the acute period, the progressive period, and the chronic period of NAION group were statistically signficant (F=10.88, P<0.05). However, no significant differences were found in the values of MD, λ┴and Length of the NAION group (F=0.23, 0.64, 0.33, 1.38;P=0.79, 0.54, 0.72, 0.27). Conclusion The parameters of DTI can be used to monitor the damage of optic nerve and development in NAION.

Objective To observe the feasibility of low tube voltage scanning technology in CT-guided cryoablation therapy of liver cancer.Methods Twenty-one patients who underwent routine CT(tube voltage 120 kV)-guided cryoablation of liver cancer(group A)were retrospectively enrolled,while low tube voltage(100 kV)CT-guided cryoablation of liver cancer was prospectively performed in 23 patients(group B).CT scanning were performed before and after ablation with automatic tube current mode(50-450 mA),and adaptive statistical iterative reconstruction(ASIR)algorithm was used for image reconstruction(reconstruction percentages of 40%)of both groups.The subjective scores and objective evaluations of CT image quality before and after treatment were compared between groups,so as the treatment effect and patient's radiation dose(volume CT dose index[CTDIvol]).Results No significant difference of subjective scores,objective evaluations of CT image quality nor treatment effect was detected between groups(all P＞0.05).Before and after treatment,CTDIvol of patients in group A was significantly higher than that in group B(btoh P＜0.001).Conclusion Low tube voltage scanning technology could be used for CT-guided cryoablation of liver cancer,which might ensure image quality without affecting evaluation on cryoablation effect and reduce radiation dose combined with ASIR algorithm.

BACKGROUNDLymphoma of the lacrimal sac is rare, often misdiagnosed clinically. This study aimed to investigate the imaging features of these tumors and provide suggestions to aid the diagnosis.

METHODSIn this retrospective study, five cases were assessed according to magnetic resonance imaging (MRI), computed tomography (CT), and pathological findings. All five patients underwent MRI and contrast-enhanced T1-weighted imaging (CE-T1WI), of which four patients underwent dynamic contrast-enhanced (DCE) MRI and three patients underwent CT.

RESULTSFour cases and one case had a lymphoma in left and right medial canthus, respectively. Soft tissue surrounding the eyelids, subcutaneous tissue in the nasal dorsum, and involvement of the entire nasolacrimal canal were demonstrated in all five lesions. In two cases, the mass invaded the extraconal space. In one case, the mass invaded the adjacent medial rectus muscle and nasal area. Well-defined margins were observed in three cases and ill-defined margins in two cases. All cases showed homogeneous isointense lesions on T1WI. Four cases showed homogeneous isointensity and one case demonstrated heterogeneous isointensity on T2WI. After contrast injection, the lesion showed slight homogeneous isointensity and moderate enhancement in four cases and heterogeneous isointensity and moderate enhancement in one case. In the four patients who underwent DCE-MRI, a plateau pattern was revealed in three cases and washout pattern in one case. In the three cases who underwent CT, two cases had isointense and one case had hyperintense lesions. The lacrimal duct was remodeled and the surrounding bone compressed.

CONCLUSIONSTumors of the lacrimal sac showed homogeneous and isointense patterns on T1WI and T2WI with mildto- moderate enhancement and a plateau pattern on DCE-MRI. CT showed remodeling of the lacrimal duct with bone compression.

Aged ; Female ; Humans ; Lymphoma ; diagnosis ; diagnostic imaging ; Magnetic Resonance Imaging ; methods ; Male ; Retrospective Studies ; Tomography, X-Ray Computed