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.

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.

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 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.

The Department of Radiology of West China Hospital of Sichuan University provides us a teaching model that image-reading combined with problem-based learning (PBL) for radiographer once a month. Based on the problem images and typical cases, after careful image-reading, radiographer is guided to think positively and propose specific solutions to the problems. Then designated personnel gives a detail lecture on related diseases, imaging performance, diagnostic requirements, conventional scanning schemes, operating specifications, common problems and image post-processing, etc., which aims at taking continuing education for radiographers.

Objective To investigate the application value of multiple?arterial?phase imaging technique with differential sub?sampling with cartesian ordering (DISCO) in the gadoxetate acid disodium enhanced liver MRI. Methods From September 2017 to March 2018, 56 patients with suspected malignant focal liver disease diagnosed with ultrasound or CT in West China Hospital of Sichuan University were enrolled prospectively, and underwent preoperative enhanced MRI with gadoxetate acid disodium. Patients were divided into 2 groups by random?number table method. Twenty nine patients in group A underwent liver multiple?arterial?phase imaging with DISCO. Twenty seven patients in group B underwent single?arterial?phase imaging with liver acquisition with volume acceleration?flex (LAVA?Flex). The display rate of late?arterial?phase and respiratory motion artifacts of dynamic enhancement images were evaluated. The categorical variables was compared by Chi?square test. The respiratory motion artifacts between the single?arterial?phase and multiple?arterial?phases were compared by Mann?Whitney U test. The artifact scores among the various phases of the multi?arterial phase were compared by Kruskal?Wallis H. Results Compared to LAVA?Flex [74.1%(20/27)], a higher display rate of late?arterial phase [96.6%(28/29)] was found in DISCO (Group A), and the difference was statistically significant (χ2=5.770, P=0.016). In the evaluation of respiratory motion artifacts, the motion artifacts of the late?arterial images obtained by LAVA?Flex [3(3,4)] were more severe than the DISCO [2(2,3)], and the difference was statistically significant (Z=-3.250, P<0.01). Among the scores of motion artifacts in the 6 phases of DISCO, the artifact scores of phase 1, 2, 3, 4, 5, 6 were [3(3,4)], [2(2,3)], [2(2,3)], [3(2,3)], [3(3,4)] and [3(3,4)], respectively. The motion artifacts of phase 2, 3, 4 were better than phase 1, 5, 6, the differences were statistically significant (P<0.05), but there was no statistical differences among phase 2, 3 and 4 (P>0.05). Conclusion Compared with single?arterial?phase imaging, multiple?arterial?phases with DISCO using gadoxetate acid disodium can improve the capture rate of late arterial phase and reduce motion artifacts.