Clinical practice of medical imaging technology undergraduates is a key link in the transformation from imaging technology students to imaging technologists. However, there are a series of problems leading to poor practice effect, e.g., imaging technology involves a lot of learning contents, and the teachers' level is uneven. Based on the above problems, some improvements have been implemented, including the establishment of the admission lecture system and tutor responsibility system, application of pluralistic teaching methods, standardizing the examination system of interns, flexible adjustment of practice time arrangements, training of practice teaching team, and so on. Finally, the quality and effect of undergraduate practice teaching in medical imaging technology has been improved significantly.

Objective To explore the optimal protocol of lower-extremity contrast-enhanced MRA (CE-MRA) in the evaluation of diabetic foot.Methods Twenty eight healthy volunteers were scanned by CE-MRA in crus twice with parellel imaging factor (PIF) of 3 or 4.The signal-to-noise ratio (SNR),contrast-to-noise ratio (CNR) and image quality of popliteal artery,posterior tibial artery,anterior tibial artery and peroneal artery were compared.Twenty patients with diabetic foot underwent CE-MRA by both of protocol 1 and 2 in leg,crus and foot.Protocol 1 was the traditional Care-bolus protocol and protocol 2 was the optimized K-space center filling delay-time protocol.The difference of two protocols in venous aliasing and in display of femoral artery,popliteal artery,posterior tibial artery,anterior tibial artery,peroneal artery,dorsalis pedis artery,medial plantar artery and lateral plantar artery were compared.The SNR,CNR of two different PIF sequences were compared by paired t test,and the display of artery of crus was compared by Wilcoxon.The display of vessels and venous aliasing of 2 protocols of diabetic foot patients were compared by Wilcoxon.Results In the images of healthy volunteers with PIF of 3,the SNR were 267±84,174±51,147±42;and the CNR were 232 ±83,139±51,108±39 at popliteal artery,posterior tibial artery and peroneal artery.However,in the images with PIF of 4,the SNR were 239±73,157±53,132±35;and CNR were 206±71,124±50,103±33,respectively.Both the SNR and CNR were higher in the former than in the latter(t values were 2.31 to 4.11,P＜0.05).There was no significant difference in the vessel display between the different PIF volunteers (P＞0.05).In the protocol 1 of patients with diabetic foot,the display of popliteal artery,posterior tibial artery,anterior tibial artery,peroneal artery,dorsalis pedis artery,medial plantar artery and lateral plantar artery,the venous aliasing in crus and foot were 3.40±0.82,2.70±0.80,2.50±1.00,2.20±0.77,2.30±0.92,2.15± 1.04,1.45±0.60,2.20± 1.01,2.20± 1.06.And in the protocol 2,they were 3.85±0.37,3.55± 0.69,3.30±0.92,2.90±0.79,3.30±0.92,3.25±0.79,1.95±1.10,3.70±0.47,3.65±0.49,respectively(P＜0.05).All of these parameters of protocol 2 were superior to protocol 1.Conclusion Using a higher PIF properly,setting the personalized K-space center filling delay-time can contribute to improving the image quality of whole lower-extremity MRA in patients with diabetic foot.

Objective To provide an automatical method for quality assurance (QA) of magnetic resonance imaging. Methods Digital imaging and communications in medicine (DICOM) protocol was used to control the process of QA calculation and storage;the region of interest was auto delineated by process. Results The parameters of stability calculated by process reflected the equipment states in a certain extent and avoided the subjectivity which referring to the region of interest. Conclusion Automatical QA method brings the convenience to QA work on aspects of acquiring, analysis and data saving.

This study was aimed to optimize the methods of magnetic resonance spectroscopy (MRS) to improve its quality in amygdala. Forty-three volunteers were examined at right and left amygdala using stimulated-echo acquisition mode (STEAM), and point-resolved spectroscopy series (PRESS) with and without saturation bands. The Cr-SNR, water-suppression level, water full width at half maximum (FWHM) and RMS noise of three sequences were compared. The results showed that (1) the Cr-SNR and water-suppression lelvel of PRESS with saturation bands were better than that of PRESS without saturation bands and STEAM (P<0.001); (2) the left and right RMS noise was significantly different both using PRESS with saturation bands and using STEAM (P<0.05); (3) there was a positive, significant correlation between Cr-SNR and voxel size (P<0.05). Therefore, PRESS with saturation bands is better than PRESS without saturation bands or STEAM for the spectroscopy of amygdala. It is also useful to make the voxel as big as possible to improve the spectral quality.
Adult ; Algorithms ; Amygdala ; metabolism ; physiology ; Artifacts ; Female ; Humans ; Magnetic Resonance Spectroscopy ; methods ; Male ; Pattern Recognition, Automated ; standards ; Young Adult

Our purpose is to introduce and analyze the data quality assurance (DQA) protocol of functional magnetic resonance imaging (fMRI). A water phantom was scanned to get DQA indexes. An fMRI sequence was used to get signal noise ratio (SNR) and Drift, which was calculated from maximum difference ratio of the average signal intensity in the region of interest (ROI) of image serials. The long period application of this method demonstrated that this DQA protocol can reflect imaging performance and the state of stability of the MRI scanner. Some application experience and discussion involved in DQA were also presented here.
Algorithms ; Artifacts ; Artificial Intelligence ; Humans ; Image Processing, Computer-Assisted ; methods ; Magnetic Resonance Imaging ; methods ; Phantoms, Imaging ; standards ; Quality Control

Objective To investigate the brain perfusion changes in patients with refractory depressive disorder (RDD) and non-refractory depressive disorder (NDD) using arterial spin labeling (ASL).Methods Present study included 12 patients with RDD, 37 patients with NDD and 42 controls,and their age, sex and handedness were matched among the three groups.FAIR sequences were performed using a 3 T MR imaging system with an 8 channel phase array head coiL The labelled and controled images were subtracted and then averaged to obtain perfusion-weighted images.The first 2 images were excluded to avoid T, equilibrium effects and then voxel based analysis was performed using SPM2. One way ANOVA analysis using age as covariance ( thresholded at P ＜ 0.01 uncorrected) was performed.Results Patients with NDD showed regional alteration of the brain perfusion, mainly involved in two frontal subcortical circuits, i.e. significantly decreased perfusion in the left frontal and thalamus (the limbic thalamo-cortical circuit) whereas significantly increased perfusion in bilateral hippocampi, fight lentiform and left anterior cingulated gyros (the limbic-striatal-pallidal-thalamic circuit).In contrast, patients with RDD presented significantly decreased perfusion involving bilateral frontal areas (the limbic-thalamo-cortieal circuit) whereby no significantly increased perfusion areas were observed.Conclusion In addition to the reported experimental evidences, our results suggest that the RDD is associated with inactivity of bilateral frontal areas, while the NDD is associated with inactivity of left frontal areas and overactivity of bilateral limbic system.

Objective:To analyze clinical, laboratory and imaging characteristics of different subtypes of linear morphea (LM) , and to propose an appropriate approach to the diagnosis and severity assessment of LM.Methods:Clinical data were collected from patients with clinically and/or pathologically confirmed LM in Department of Dermatology, West China Hospital, Sichuan University from January 2018 to December 2019, and retrospectively analyzed.Results:A total of 107 patients with LM were enrolled into this study, including 63 with LM of the limbs/trunk, 22 with morphea en coup de sabre, 11 with progressive hemifacial atrophy and 11 with eosinophilic fasciitis. Disease severity was evaluated by using the modified localized scleroderma skin severity index (mLoSSI) and localized scleroderma skin damage index (LoSDI) scores in 88 patients, with the mLoSSI scores ranging from 0 to 51 points, and the LoSDI scores ranging from 0 to 40 points. Routine blood examination of 10 patients with eosinophilic fasciitis showed increased eosinophil counts in 4 patients. Thirteen (14.8%) of 88 patients with LM were positive for antinuclear antibody, with titers of ≥ 1∶320. Magnetic resonance imaging (MRI) examination showed ipsilateral cerebral hemisphere atrophy and contralateral white matter hyperintensity on T2-weighted images in 2 out of 4 patients with progressive hemifacial atrophy, myofascial thickening in 26 out of 28 patients with LM of the limbs/trunk (92.9%) , subcutaneous septal and myofascial thickening in all 11 patients with eosinophilic fasciitis.Conclusions:The preliminary assessment of disease activity, severity and prognosis of LM can be made by mLoSSI and LoSDI. MRI examination is recommended for patients with clinical signs of involvement of subcutaneous structures.

Objective:To explore the efficiency of MR psychoradiology examination in screening and classification of psychiatric disorders as well as its potential clinical application.Methods:Retrospective study was conducted for 144 patients with MR psychoradiology examination, who were diagnosed mental disorders based on International Statistical Classification of Diseases and Related Health Problems Tenth Revision (ICD-10) from September 2018 to July 2020 in West China Hospital of Sichuan University. As our previous studies, imaging diagnostic models were constructed based on gray matter volume (GMV) analysis for four kinds of psychiatric disorders, including depression, anxiety disorder, bipolar disorder and schizophrenia. For 120 patients with psychiatric disorders, the GMV change pattern of brain regions was detected and subtyped by MR psychoradiology examination with 50% similarity threshold of the above imaging diagnostic models. The diagnostic efficiency of MR psychoradiology examination was evaluated with references of clinical diagnose. For 24 patients with dementia, brain atrophy was additionally measured by conventional MR examination and MR psychoradiology examination respectively.Results:The sensitivity, specificity, Youden index and accuracy of MR psychoradiology in identifying the four psychiatric disorders were 86.6% (84/97), 69.6% (16/23), 0.56 and 83.3% (100/120), including depression [77.8% (28/36), 69.0% (58/84), 0.47, 71.7% (86/120)], schizophrenia [58.8% (10/17), 91.3% (94/103), 0.50, 86.7% (104/120)], bipolar disorder [42.1% (8/19), 96.0% (97/101), 0.38, 87.5% (105/120)] and anxiety disorder [24.0% (6/25), 100% (95/95), 0.24, 84.2% (101/120)]. As for 24 patients with dementia, 58.3% (14/24) were detected with brain atrophy by conventional MR examination, while 91.7% (22/24) were detected by MR psychoradiology examination.Conclusions:MR psychoradiology can detect the subtle brain structural abnormalities of patients with mental disorders. Although it can′t be used as an independent biomarker for disease diagnosis till now, it is of great help in improving the accuracy and objectivity of diagnosis.

Objective:To explore the application effect of case-based learning (CBL) and lecture-based learning (LBL) in the teaching of image post-processing course in the standardized training system of medical imaging technology.Methods:A total of 34 trainees in the standardized training of imaging technology of Batch 2018 in West China Hospital of Sichuan University were divided into the experimental group and the control group according to their student numbers, with 17 students in each group. CBL teaching was carried out in the experimental group, and LBL teaching was carried out in the control group. According to the standardized training course design, after one year of image post-processing course teaching, the teaching effect was evaluated through closed-book examination, questionnaire survey and post-processing test. SPSS 20.0 was used for t-test and Mann-Whitney U test. Results:The scores of closed-book examinations (74.42±6.10) and post-processing test (73.47±6.03) in the experimental group were higher than those in the control group [(69.11±3.70) and (69.08±6.51)], and the difference was statistically significant ( P<0.05). The questionnaire survey showed that the students in the experimental group recognized CBL teaching in terms of learning interests stimulation, classroom atmosphere mobilization, clinical thinking cultivation, self-study ability training, and analysis of difficult and rare cases, etc. Conclusion:In the image post-processing course of standardized training of medical imaging technology, the rational application of CBL teaching mode is helpful to improve students' learning enthusiasm, self-learning ability, comprehensive analysis of clinical ability, practical ability, innovation consciousness and so on.

Combing with the professional characteristics of imaging technology, Radiological Department of West China Hospital, Sichuan University established the STAR training model for imaging technologists to cultivate the scientific research quality of young technicians, which includes sub-professional group training, tutor responsibility system, arrangement of research time, and reading-film session of technologists. Practice shows that this training model has made a series of achievements so far, such as that the number of publishing articles, funds application, authorized patents and oral presentation at international congress has been significantly increased. In addition, there is a high recognition of the STAR training model among young imaging technologists. Therefore, the STAR model can stimulate the scientific research passion of young technologists, and improve their scientific research capability.