ObjectiveTo evaluate the dynamic changes of blood flow and blood pressure of acute hindlimb ischemia of rats by laser Doppler flowmetry (LDF) and laser Doppler perfusion imaging (LDPI). MethodsThe acute hindlimb ischemia model of rats was established by resection of rats femoral arteries of left hindlimb. The blood flow and blood pressure between operated and nonoperated hindlimbs were examined by LDF on 2, 7, 14, 28, and 49 d after operation. And the blood flow was evaluated by LDPI on 7 d after operation. ResultsAll rats survived after operation and no hindlimb necrosis occurred. The mean score was 2 on 14 d after operation and 1 on 49 d after operation. The ratio of blood flow between operated and nonoperated hindlimbs on 2 d after operation significantly increased from 1 to 1.31±0.439 (P=0.021). The ratio of blood flow on 7 d (0.82±0.538) and 14 d (0.93±0.294) after operation was significantly lower than that on 2 d after operation (P=0.032 and P=0.019), although the difference between the two former was not significant (P=0.502). Furthermore, the ratio of blood flow on 28 d after operation reached the bottom (0.41±1.970), which was obviously lower than that on 2, 7, and 14 d after operation (P=0.004, P=0.007, and P=0.006). The blood flow of operated hindlimbs recovered approximately the value before operation (0.98±0.093), which was significantly lower than that on 2 d (P=0.010), higher than that on 28 d (P=0.005), but not different from that on 7 d and 14 d after operation (P=0.126 and P=0.382). The ratio of blood pressure between operated and nonoperated hindlimbs on 2 d after operation significantly increased from 1 to 0.47±0.375 (P=0.031). The ratio of blood pressure decreased on 7 d after operation (0.44±0.118), which was not different from that on 2 d after operation (P=0.203). Furthermore, the ratio of blood pressure on 14 d after operation reached the bottom (0.35±0.115), which was obviously lower than that on 2 d and 7 d after operation (P=0.001 and P=0.036). On 28 d after operation, the ratio of blood pressure increased (0.54±0.146), which was significantly higher than that on 14 d after operation (P=0.008), while not different from that on 2 d (P=0.493) and 7 d after operation (P=0.551). The ratio of blood pressure recovered approximately the value before operation (0.97±0.094), which was significantly higher than that on 2, 7, 14, and 28 d (P=0.013, P=0.021, P=0.002, and P=0.031). ConclusionAcute hindlimb ischemia model of rats can be established by resection of rats femoral arteries of left hindlimb and the most serious stage of hindlimb ischemia is on 14-28 d after operation. LDF and LDPI are of importance for monitoring the dynamic changes of rats hindlimb ischemia after operation.
Objective To evaluate the diagnostic value of magnetic resonance cholangiopancreatography (MRCP) in obstructive jaundice. Methods Forty eight consecutive patients with obstructive jaundice were examined by MRCP, all results were testified during and /or after operation. Results Different causes of obstruction had their own characteristic manifestations. Level of obstruction was accurate in 100%, the accuracy in distinguishing obstructive causes was 93.8%. Conclusion MRCP is quite effective, safe and reliable in diagnosis of obstructive jaundice.
ObjectiveTo observe the multimodal imaging characteristics of combined hamatoma of the retina and retinal pigment epithelium (CHRRPE).MethodsA retrospective case study. From January 2013 to December 2017, 6 CHRRPE patients (6 eyes) diagnosed in Department of Ophthalmology, Sun Yat-sen Memorial Hospital were included in the study. There were 4 males and 2 females, with the mean age of 12.0±8.10 years. There were 5 eyes with BCVA ≤0.1, 1 eye with BCVA＞1.0. Corneal fluoroscopy showed 1 eye with an external oblique 15°, and the remaining eye had no abnormalities in the anterior segment. All eyes underwent fundus color photography, FAF, FFA, ICGA, OCT and color Doppler flow imaging (CDFI). The multimodal imaging characteristics were observed.ResultsAll the affected eyes CHRRPE were located in the posterior pole and showed mild elevation. Most of the retinal neuroepithelial layers had different degrees of hyperplasia, vascular tortuosity and retinal folds. Of the 6 eyes, 4 eyes (66.7%) involving the macula and optic disc, only 2 eyes (33.3%) involving the macula. OCT showed that the structure of the neuroepithelial layer was unclear and the signal intensity was uneven; it involved 2 eyes of the whole retina (33.3%) and only 4 eyes of the neuroepithelial layer (66.7%). FFA and ICGA showed that the choroidal background fluorescence of the early lesions was weakened, and the lesions showed slightly weak fluorescence; the late telangiectasia fluorescein was obviously leaked, and the lesions were stained with fluorescence. FAF mainly appears as weak autofluorescence with a small amount of strong autofluorescence. CDFI has no characteristic performance.ConclusionsCHRRPE is mainly a membrane-like hyperplasia without angiogenesis, involving the retinal neuroepithelial layer, and may also involve the entire retina. OCT is dominated by strong reflection; AF, FFA and ICGA are mainly weak fluorescence.
ObjectiveTo evaluate the spectral domain optical coherence tomography (SD-OCT) characteristics of polypoidal choroidal vasculopathy (PCV) and its correlation with the visual acuity after photodynamic therapy (PDT) combined with intravitreal ranibizumab. MethodsTwenty-six eyes of 26 patients with PCV diagnosed by indocyanine green angiography (ICGA) were enrolled in this study. All the patients were examined for best corrected visual acuity (BCVA), slit lamp microscope, SD-OCT, fundus fluorescein angiography (FFA) and ICGA before and 1, 3 months after treatment. The mean baseline BCVA was (31.46±16.87) letters, mean central retinal thickness (CRT) was (581.19±309.05) μm, and mean subfoveal choroidal thickness (SFCT) was (248.92±95.45) μm. Patients were divided into 2 groups according to the final visual improvement after 6 month of treatment: GR or sensitive Group (17 eyes) and PR or non-sensitive Group (9 eyes). GR group included 12 males and 5 females, with a mean age of (65.24±7.03) years, a mean CRT of (619.06±335.07) μm and a mean SFCT of (271.24±106.61) μm. There were 4 eyes with subretinal hemorrhage (SRH), 2 eyes with interface retinal fluid (IRF), 13 eyes with subretinal fluids (SRF) and 15 eyes with pigment epithelial detachment (PED). PR group included 8 males and 1female, with a mean age of (64.00±7.02) years, a mean CRT of (509.67±255.21) μm and a mean SFCT of (271.24±106.61) μm. There were 6 eyes with subretinal hemorrhage (SRH), 5 eyes with interface retinal fluid (IRF), 6 eyes with subretinal fluids (SRF) and 8 eyes with pigment epithelial detachment (PED). The difference of sex, age, CRT and SFCT between these two groups was not significant (P>0.05). The relationship of baseline SD-OCT and post-treatment BCVA was analyzed. ResultsOn 1, 2, 3, 6 months after treatment, the BCVA were (38.46±19.81), (40.04±20.80), (42.96±21.63), (43.77±20.91) letters respectively. On 6 months after treatment, the mean CRT in GR and PR group were (360.71±276.54), (341.44±193.68) μm respectively (P>0.05). 64.71% (11/17) eyes in GR group and 22.22% (2/9) eyes in PR group had a SFCT thicker than 263μm. The difference was statistical significant between two groups [odds ratio (OR):0.052, 95% confidence interval (CI):0.005-0.533; P=0.013]. Logistic regression analysis showed that existence of IRF (OR=9.375, 95% CI: 1.299-67.645; P=0.026) or SRH (OR=6.500, 95% CI: 1.094-38.633; P=0.040) at baseline was negative prognostic factor to treatment. ConclusionThick SFCT is a protective factor, however, existence of IRF or SRH at baseline is negative prognostic factor of final visual improvement.
In order to protect the integrity and function of the digestive system, duodenum-preserving total pancreatic head resection is becoming the surgical method which was chosen by more and more doctors for benign lesions or low-grade malignant tumors of the pancreatic head. With the development of minimally invasive concepts and techniques, laparoscopic technology has brought unique advantages to this surgery. In this paper, a series of problems such as the development process and indications of laparoscopic duodenum-preserving total pancreatic head resection were discussed, and the core techniques of surgery and how to reduce the occurrence of complications were emphasized. The aim is to improve the therapeutic effect and quality of life of patients through reasonable surgical methods and treatment strategies.
Biodistribution of125I-labeled 17α-vinyestradiol-3-acetate (125I-VE2A)in nude mice bearing human breast cancer containing different estrogen receptor (ER) content was studied to understand the relation between this compound and ER and, consequently, to develop the ER imaging. Each mouse was injected with 92.5 kBq tracer from tail vein and then killed after two hours. The radioactivity uptake rate in one gram of tumor tissue and tissues from other vital organs were measured, and the radioactivity uptake ratio of tumor to nontumor tissue was also measured. Results: The radioactivity uptake rate and the radioactivity uptake ratio of tumor to nontumor tissue in ER positive tumor (MCF-7) were much higher than those in ER negative tumor (MDA-MB-231). Conclusions: This compound, IVE2A has affinity to ER positive target organ or tumor and promise the probability to define the content and site of ER in vivo or in tumor.
Objective To investigate the correlation of red blood cell distribution width (RDW) and neutrophil to lymphocyte ratio (NLR) with total imaging load of cerebral small vessel disease (CSVD), and the clinical diagnostic value of RDW, NLR and their combined indicators for high load of CSVD imaging. Methods The medical records of CSVD patients hospitalized in the Department of Neurology of Baotou Central Hospital between October 2018 and October 2022 were retrospective collected. The total imaging load of CSVD was obtained by evaluating the cranial MRI and divided into a low load group and a high load group. The general clinical data, past medical history, and blood biochemical indicators were compared between the two groups. The correlation analysis method was used to analyze the relationship between the relevant indicators and the total imaging load. Logistic regression analysis was used to analyze the risk factors of the total imaging load of CSVD. The receiver operating characteristic (ROC) curve was used to evaluate the diagnostic value of the detection indicators for clinical diagnosis. Results A total of 320 patients were included. Among them, there were 201 cases (62.81%) in the low load imaging group and 119 cases (37.19%) in the high load imaging group. Excepted for age, gender, history of hypertension, RDW, and NLR (P<0.05), there was no statistically significant difference in the comparison of other indicators between the two groups (P>0.05). Spearman correlation analysis showed that RDW (r=0.445, P<0.001) and NLR (r=0.309, P<0.001) were positively correlated with the total imaging load of CSVD. The results of multivariate logistic regression analysis showed that age, male gender, RDW, and NLR were risk factors for high imaging load of CSVD. The areas under the ROC curve of RDW, NLR, and their combined indicators were 0.733, 0.644, and 0.792, respectively.Conclusions In patients with CSVD, the levels of RDW and NLR are related to the total imaging load of CSVD, which are independent risk factors for high imaging load of CSVD. The levels of RDW and NLR have clinical diagnostic value in predicting CSVD high load.
The portable light-weight magnetic resonance imaging system can be deployed in special occasions such as Intensive Care Unit (ICU) and ambulances, making it possible to implement bedside monitoring imaging systems, mobile stroke units and magnetic resonance platforms in remote areas. Compared with medium and high field imaging systems, ultra-low-field magnetic resonance imaging equipment utilizes light-weight permanent magnets, which are compact and easy to move. However, the image quality is highly susceptible to external electromagnetic interference without a shielded room and there are still many key technical problems in hardware design to be solved. In this paper, the system hardware design and environmental electromagnetic interference elimination algorithm were studied. Consequently, some research results were obtained and a prototype of portable shielding-free 50 mT magnetic resonance imaging system was built. The light-weight magnet and its uniformity, coil system and noise elimination algorithm and human brain imaging were verified. Finally, high-quality images of the healthy human brain were obtained. The results of this study would provide reference for the development and application of ultra-low-field magnetic resonance imaging technology.
ObjectiveTo explore the value of 3.0 T MRI functional imaging in differential diagnosis of radiation brain injury and recurrence of glioblastoma multiforme.MethodsFrom March 2017 to January 2018, 31 patients diagnosed with brain glioblastoma multiforme in Peking University International Hospital were collected continuously, including 14 cases of tumor recurrence and 17 cases of radiation-induced brain injury. All the patients routinely underwent conventional MRI head scan, three-dimension arterial spin labeling (3D-ASL), dynamic susceptibility contrastperfusion weighted imaging (DSC-PWI), and enhanced MRI scan sequence; related parameters were recorded and compared.ResultsCerebral blood flow (CBF) value of abnormal enhanced area in the recurrence group was significantly higher than that in the brain injury group with 3D-ASL scan (t=3.016, P=0.005), and no difference was found in edema area between the two groups (P>0.05). In the recurrence group, CBF value of abnormal enhanced area was significantly higher than that of the normal area (t=2.628, P=0.014); however, there was no significant difference in the CBF value between the abnormal enhancement foci and the normal areas in the radiation brain injury group (P>0.05). Relative cerebral blood volume (rCBV) ratio (t=2.894, P=0.007) and relative cerebral blood volume (rCBF) ratio (t=2.694, P=0.012) of abnormal enhanced area, as well as rCBV ratio (t=2.622, P=0.013) and rCBF ratio (t=2.775, P=0.010) of edema area in the recurrence group were significantly higher than those in the brain injury group with DSC-PWI scan. No differences were found in relative mean transit time (rMTT) ratio and relative time to peak (rTTP) ratio between the two groups (P>0.05). In the brain injury groupr, CBV ratio (t=2.921, P=0.008) and rCBF ratio (t=3.100, P=0.004) of abnormal enhanced area were significantly higher than those of the edema area, and no difference was found in rMTT ratio or rTTP ratio (P>0.05). In the recurrence group, no difference was found in all focal parameters between abnormal enhanced area and edema area (P>0.05). In diagnosis value analysis, the areas under the curve of CBF in 3D-ASL scan, and rCBF ratio, rCBV ratio in DSC-PWI scan were 0.752, 0.675, and 0.645, respectively; the cut-off values were 34.59, 1.48, and 1.67, respectively; the sensitivities were 79.2%, 61.5%, and 58.3%, respectively; and the specificities were 44.4%, 32.8%, and 22.4%, respectively.ConculsionThe diagnostic value of functional MRI imaging in distinguishing glioblastoma multiforme recurrence and radiation-induced brain injury is high recommendated; further research and clinical application should be needed.
One of the main technical challenges when integrating magnetic resonance imaging (MRI) systems with medical linear accelerator is the strong interference of fringe magnetic fields from the MRI system with the electron beams of linear accelerator, making the linear accelerator not to work properly. In order to minimize the interference of magnetic fields, a magnetic shielding cylinder with an open structure made of high permeability materials is designed. ANSYS Maxwell was used to simulate Helmholtz coil which generate uniform magnetic field instead of the fringe magnetic fields which affect accelerator gun. The parameters of shielding tube, such as permeability, radius, length, side thickness, bottom thickness and fringe magnetic fields strength are simulated, and the data is processed by MATLAB to compare the shielding performance. This article gives out a list of magnetic shielding effectiveness with different side thickness and bottom thickness under the optimal radius and length, which showes that this design can meet the shielding requirement for the MRI-linear accelerator system.