ABSTRACT
Objective:To evaluate the clinical value of 5.0 T ultra-high filed MRI system in assessing intracranial arteries segments and vessel branchers.Methods:This study was a prospective study. Totally 40 consecutive healthy volunteers were recruited from Zhongshan Hospital, Fudan University from September 1, 2021 to November 30, and all participants who underwent either 3.0 T or 5.0 T time-of-flight MR angiography (TOF-MRA) in random order were divided into 3.0 T MR group and 5.0 T MR group with 20 volunteers for each group. Image quality was assessed by Likert 5 scoring systems and signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR),and score in visualization of intracranial arteries [middle cerebral artery (MCA) and its segments, anterior cerebral artery (ACA) and its segments, posterior cerebral artery (PCA) and its segments, lenticulostriate arteries (LA) and pontine artery (PA)] were assessed from 0 to 3 (≥2: good depiction of vessel segment). Quantitative indicators were compared between 2 groups using independent t test or Mann-Whitney U test. Results:Among the 40 subjects, there were 29 males and 11 females, aged 20-69 (50±12) years. SNR and CNR were both significantly higher in 5.0 T MR group than those in 3.0 T MR group (SNR: 187±9 vs 91±4, t=31.59, P<0.001; CNR: 156±7 vs 70±4, t=31.45, P<0.001), but there was no significant difference in subjective scores of image quality between the 5.0 T MR and 3.0 T MR groups [5.0 (4.0, 5.0), 5.0 (5.0, 5.0) points, respectively, Z=-1.23, P=0.218]. In the evaluation of cerebral arteries, the visualizations of the proximal and middle segments of MCA, ACA and PCA was better than those in the 3.0 T MR group, and there was no significant difference in the scores ( P>0.05), while the visualizations of proximal arteries in the 5.0 T MR group were significantly better than those in the 3.0 T MR group ( P<0.05). Furthermore, small vessel branches such as LA and PA in 5.0 T MR group were visualized better than those in 3.0 T MR group ( P<0.001). Conclusion:TOF-MRA by ultra-high filed 5.0-T provides an optimal choice in visualization of distal large arteries and small vessel branches, which could be useful for the diagnosis on cerebral vascular disease.
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Objective To analyze quantitatively intravoxel incoherent motion diffusion weighted imaging (IVIM-DWI)of normal adult kidney and to evaluate the effects of the location of the kidney,gender and age on IVIM-DWI parameters.Methods Thirty healthy adult volunteers were recruited to undergo IVIM-DWI examination.Two radiologists measured the D ,D? and f values of renal parenchyma in both the upper pole,middle part and lower pole of the kidneys separately.Results The D ,D? and f values of the middle part of kidneys in healthy adult were(1.61±0.1 6)×10 -3 mm2/s,(1 7.45 ±3.78)×10 -3 mm2/s and (26.88 ±5.1 9)%, respectively.The D values of right kidney were higher than that of left kidney (P 50 years group were lower than that of ≤50 years group (t = 3.548,P=0.001).D value of the kidney and age was negatively correlated (r=-0.406).Intraclass correlation coefficient of D,D? and f values between two observers were 0.881,0.56 and 0.741,respectively.The consistency of two observers in measurement of IVIM-DWI parameters in the middle part of kidneys was higher than that of the upper pole and lower pole of the kidneys.Conclusion The IVIM-DWI parameters of adult normal kidneys are influenced by different parts of the kidney,gender and age.
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Objective To evaluate MDCT findings and characteristics of metastatic pancreatic tumors. Methods A total of 23 cases with metastatic pancreatic tumors were collected and the CT findings including the size, number, location, density patterns, enhancement patterns and secondary signs (dilatation of the pancreatic duct and/or bile duct, involvement of peripancreatic vessels, atrophy of distal pancreas) were analyzed retrospectively. Results A total of 35 metastatic pancreatic tumors were identified in the 23 patients. Tumors were multiple in 7 patients, the other 16 patients had single metastatic pancreatic tumor. The mean maximum diameter of the tumors was 3. 3 cm; the majority was located in the pancreatic body/tail. Thirty tumors demonstrated no enhancement in the arterial phase, and in the portal phase 23 tumors were hypodensive compared with normal pancreatic tissue, 4 tumors were isodense and 3 tumors showed a peripheral rim of enhancement. Five tumors showed markedly enhancement in the arterial and portal phase. Only 1 patients had dilated biliary and pancreatic duct, and 2 patients had dilated pancreatic duct. Only 1 case demonstrated involvement of splenic vein. 13 of the 23 patients had extra-pancreatic metastasis. Conclusions Pancreatic metastasis showed certain imaging characteristics. The accuracy of CT diagnosis could be improved by understanding of these CT findings and clinical features.