Objective To develop a modified short time inversion recovery (STIR) sequence grading system for lumbar intervertebral disc degeneration based on MRI STIR sequences, and to test the validity and reproducibility of this grading system. Methods A modified 8-level grading system for lumbar intervertebral disc degeneration based on routine sagittal STIR sequences and modified Pfirrmann grading system was developed. Between April 2011 and February 2012, 60 patients with different degrees of lumbar intervertebral disc degeneration were selected as objects of study, including 32 males and 28 females with an average of 50 years (range, 17-85 years). T2 weighted and STIR sequence images were obtained from the lumbar discs of L1, 2-L5, S1 of each object (total, 300 discs). All examinations were analyzed independently by 3 observers and a consensus readout was performed after all data collected. The validity and reproducibility were analyzed by calculating consistent rate and Kappa value. Results According to the grading system, there were 0 grade 1, 83 (27.7%) grade 2, 87 (29.0%) grade 3, 66 (22.0%) grade 4, 31 (10.3%) grade 5, 15 (5.0%) grade 6, 12 (4.0%) grade 7, and 6 (2.0%) grade 8. Intra-observer consistency was b (Kappa value range, 0.822-0.952), and inter-observer consistency was high to b (Kappa value range, 0.749-0.843). According to the consensus analysis, the total consistent rate was 82.7%-92.7% (mean, 85.6%). A difference of one grade occurred in 13.9% and a difference of two or more grades in 0.5% of all the cases. Conclusion Disc degeneration can be graded by using modified STIR sequence grading system, which can improve the accuracy of grading different degrees of lumbar intervertebral disc degeneration.
ObjectiveTo investigate the diagnostic value of spectral saturation inversion recovery, gradient-echo chemical shift MRI， and proton magnetic resonance spectroscopy in quantifying hepatic fat content. MethodsConventional T1-weighted and T2-weighted scanning (without fat saturation and with fat saturation)， gradient-echo T1W in-phase （IP） and opposedphase （OP） images and 1H-MRS were performed in 31 healthy volunteers and 22 patients who were candidates for liver surgery. Signal intensities of T1WI amp; T1WIFS (SInonfat1, SIfat1), T2WI amp; T2WI-FS (SInonfat2, SIfat2), and IP amp; OP (SIin, SIout) were measured respectively, the relative signal intensity one (RSI1), relative signal intensity two (RSI2)， and fat index (FI) were calculated. Peak values and the area under peak of 1H-MRS were measured, and the relative lipid content of liver cells (RLC ) were calculated. Twenty-two patients accepted liver resection and histological examination after MRI scanning, the proportion of fatty degenerative cells were calculated by image analysis software. Results①Hepatic steatosis group showed higher average values of RSI1, FI， and RLC to non-hepatic steatosis group (Plt;0.05), while there was no significant difference in RSI2 between two groups (Pgt;0.05). ②There was a statistical significant difference in RLC among different histopathological grades of hepatic steatosis, and RLC increased in parallel with histopathological grade (Plt;0.05).There was no significant difference in RSI2, RSI1, and FI among different histopathological grades, although the latter two had a tendency of increasing concomitant with histopathological grade (Pgt;0.05). ③The values of FI and RLC were positively correlated with the PFDC （r=0468, P=0.027； r＝0771， Plt;0.000 1）, while they were not in RSI1 and RSI2 (r=0.411, P=0.057； r=0.191, P=0.392). ConclusionsSPIR, Gradient-echo chemical shift MRI and 1H-MRS can help to differentiate patients with hepatic steatosis from normal persons, the latter also can help to classify hepatic steatosis. In quantifying hepatic fat content, 1H-MRS is superior to gradient-echo chemical shift MRI, while SPIR’s role is limited.
It is difficult to reflect the properties of samples from the signal directly collected by the low field nuclear magnetic resonance (NMR) analyzer. People must obtain the relationship between the relaxation time and the original signal amplitude of every relaxation component by inversion algorithm. Consequently, the technology of T2 spectrum inversion is crucial to the application of NMR data. This study optimized the regularization factor selection method and presented the regularization algorithm for inversion of low field NMR relaxation distribution, which is based on the regularization theory of ill-posed inverse problem. The results of numerical simulation experiments by Matlab7.0 showed that this method could effectively analyze and process the NMR relaxation data.
ObjectivesTo study the gray matter (GM) volume of MRI-negative temporal lobe epilepsy (TLE) patients with double inversion recovery (DIR) combining with SPM analysis.MethodsTwenty-four MRI-negative TLE patients and twenty-four healthy controls (HC) with matched sex and age were collected from Zhongshan hospital from 2016 Januany to 2018 December. All the participants underwent DIR scanning and the MRI data were further postprocessed with Statistical Parametric Mapping (SPM).ResultsMRI-negative TLE patients showed reduced GM density in the left superior frontal gyrus (medial orbital), right temporal pole, right para-hippocampal gyrus, right lingual gyrus, and increased GM value in the right superior frontal gyrus (medial) than HC group with statistical significance (P<0 001="" cluster="">50). According to the EEG manifestation, the MRI-negative TLE group was classified into the multiple and single focal discharges group.The multiple focal discharges MRI-negative TLE group demonstrated decreased GM density in the right temporal pole, right superior occipital gyrus, right para-hippocampal gyrus and bilateral superiorfrontal gyrus (medial orbital), but increased GM value in the right superior frontal gyrus (medial) than HC group with statistical significance (P<0 001="" cluster="">50). No statistical differences were found in the single focal discharges MRI-negative TLE group comparing with either the HC or multiple focal discharges group. According to the seizure type with or without secondarily generalizedtonic-clonic seizures, the MRI-negative TLE patients were classified into sGTCS and non-sGTCS group. There existed greater statistical GM density for sGTCS group in the right lingual gyrus, right thalamus, left middle occipital gyrus, left basal ganglia and left cuneus than the non-sGTCS group (P<0 001="" cluster="">50).ConclusionsThere existed wider areas of GM volume changes in the brain regions of MRI negative TLE patients, including both the temporal and extra-temporal areas, with most significant GM alteration in multiple focal discharges and sGTCS TLE group.
To improve the cavitation-to-tissue ratio (CTR) of cavitation imaging during the treatment with high-intensity focused ultrasound (HIFU), we proposed a pulse inversion based broadband subharmonic cavitation imaging method (PIBSHI). Due to the fact that the subharmonic signal is a unique nonlinear vibration characteristic of cavitation bubbles, we extracted the broadband subharmonic signal to get a high-CTR cavitation imaging. The simulation showed that the subharmonic signal produced by cavitating bubbles with different sizes varied, and the signal was stronger than other subharmonics when the bubbles’ resonant frequency was close to 1/2 subharmonic frequency. Further experiment results demonstrated that compared with the conventional B-mode images, broadband subharmonic cavitation imaging (BSHI) has improved the CTR by 5.7 dB, and the CTR was further improved by 3.4 dB when combined with pulse inversion (PI) technology. Moreover, when the bandwidth was set to 100%~140% of the 1/2 subharmonic frequency in PIBSHI, the CTR was the highest and the imaging showed the optimal quality. The study may have reference value for the development of precise cavitation imaging during HIFU treatment, and contribute to improve the safety of HIFU treatment.
ObjectiveTo evaluate the short-term therapeutic effect of extended adventitial inversion with graft eversion anastomosis technique in the root treatment of acute type A aortic dissection (ATAAD).MethodsFrom November 2019 to July 2020, 28 patients with ATAAD were treated by extended adventitial inversion with graft eversion anastomosis technique in the Department of Cardiovascular Surgery, Dalian Municipal Central Hospital, including 19 males and 9 females, aged 60.11±11.11 years. The intima of the ascending aorta was trimed to 5 mm above the sinotubular junction. The adventitia of the ascending aorta was longitudinally cut to the reserved intima margin along the junction of the three aortic valves. The extended adventitial inversion was sutured continuously, no coronary sinus was sutured over the aortic annulus, and the left and right coronary sinus was sutured above the coronary ostium. The anastomotic graft was everted and inserted into the aortic lumen, and the everted graft was continuously sutured at the level of sinotubular junction which was 5 mm away from the edge of graft.ResultsThere was no intraoperative death, intractable root hemorrhage, residual root false lumen, root dilatation, anastomotic hematoma or other complications. There was no recurrence of the pain in the back of all patients, and the results of the CT angiography were not significantly changed. In 22 patients with no regurgitation, only 1 (4.55%) patient had a mild regurgitation. In 6 patients with mild aortic regurgitation, the disappearance rate of regurgitation was 50.0% (3/6).ConclusionThe treatment of extended adventitial inversion with graft eversion anastomosis technique in the root treatment of aortic dissection eliminates the residual dissection at the root. The anastomotic hemorrhage is prevented, the root structure of aortic dissection is reconstructed and strengthened, the root function is restored, and the possible expansion of the root is prevented. The short-term results are satisfactory.
ObjectiveTo explored the accuracy and effectiveness of “swimming pool” sign in recognizing fluid attenuated inversion recovery sequence (FLAIR) compared with traditional methods, and to solve the difficulties in distinguishing T1 weighted image (TIWI) and FLAIR in clinical medical students and junior residents. Methods Using the observational research method, forty standardized training physicians who rotated in the Department of Neurology, West China hospital of Sichuan University were included as the research objects between September and November 2021. Standardized training physicians were randomly divided into “swimming pool” sign group and control group, with 20 persons in each group. In the same period, 100 patients with central nervous system infection, cerebral vascular disease, dementia syndrome, multiple sclerosis and no obvious intracranial lesions were selected from the Department of Neurology, West China Hospital of Sichuan University between September and November 2021. According to the diagnosis, the patients were divided into 5 groups with 20 cases in each group. Two groups were given the same 20 images respectively, including T1WI and FLAIR. Record the accuracy, total time-consuming and time-consuming per image of each standardized training physicians. Results Each patient had “swimming pool” sign. Under different backgrounds, the accuracy of the “swimming pool” sign group was higher than that of the control group (P<0.001), while the total time-consuming and time-consuming per image were lower than that of the control group (P<0.001). Conclusions In different nervous system diseases, “swimming pool” sign is stable on FLAIR. Compared with traditional methods, “swimming pool” sign can quickly and accurately distinguish T1WI and T2 FLAIR.