Objective To observe the value of 5.0T MR susceptibility weighted imaging(SWI)for displaying cerebral small veins and detecting cerebral microbleeds(CMB).Methods Head MR examinations were prospectively performed using both 3.0T and 5.0T MR scanner in 30 stroke patients suspected caused by cerebral small vessel disease.The image quality,effect of displaying cerebral small veins and detecting CMB were compared between 3.0T and 5.0T SWI.Results The image quality scores,signal-to-noise ratios,contrast-to-noise ratios,scores of displaying deep cerebral veins and subcortical veins,the counts of detecting CMB and iron deposition on cortical surface of 5.0T SWI were all higher than those of 3.0T SWI(all P＜0.05).High consistency of CMB positions was found between 3.0T and 5.0T SWI(Kappa=1.0).Conclusion The effect of 5.0T MR SWI for displaying cerebral small veins and detecting cerebral microbleeds were better than 3.0T MR SWI,which could be used to assess stroke caused by cerebral small vascular disease.

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.

Objective To compare the compressed sensing (CS)and parallel imaging (PI)techniques applied to contrast-enhanced MRI (CE-MRI)scanning of liver and to determine their clinical applicability.Methods Thirty patients with liver mass who underwent the CE-MRI scanning with both CS and PI techniques were recruited in the current study.The SNR of the liver,acquisition time and subjective image quality scores were compared between CS (CE-MRI with CS)and PI (CE-MRI with PI)groups respectively.Results The SNR values of pre-enhancement T1 WI in CS group were lower than those in PI group (1 97.82±32.5 3 vs 204.94±35.28,P＜0.05).However,there was no significant difference in the SNR values of images in equilibrium phase between the two groups (CS vs PI:392.38±72.93 vs 405.03±82.09,P＞0.05).The acquisition time in CS group was significantly shorter than that in PI group [(11.71±0.23)s vs (17.85±0.42)s, P＜0.01].Significantly higher subjective image quality scores were found in CS group than those in PI group (3.54±0.57 vs 2.91±0.80,P＜0.01). Conclusion CS technique may benefit the patients who cannot hold breath well and improve the CE-MRI image quality.

Objective: To investigate the diagnostic value of extracellular volume (ECV) imaging by magnetic resonance imaging for liver fibrosis of hepatitis B. Methods: A retrospective analysis was recruited in patients with chronic hepatitis B, who underwent liver surgery from April to October 2017 for pathological evaluation of liver tissues, and all patients underwent Gd-EOB-DTPA-enhanced T1 mapping to calculate the liver ECV score. The correlation between ECV and staging of hepatic fibrosis and inflammatory activity were compared to clarify the diagnostic value of staging of fibrosis. Results: 66 patients were enrolled in this study. Concerning the staging of liver fibrosis, there were 13, 4, 13, 10, and 26 cases with F0, F1, F2, F3 and F4 stages, respectively. ECV values had high interobserver consistency (correlation coefficient 0.860). The ECV difference between different stages of liver fibrosis was statistically significant (F = 15.02, P < 0.001). There was a significant positive correlation between ECV and fibrosis stage (r = 0.622, P < 0.001), and weak correlation with inflammatory activity (r = 0.332, P = 0.007). Fibrosis staging was an independent factor influencing ECV (P < 0.001). The area under the receiver operator characteristic curve for the diagnosis of liver fibrosis staging F≥1, F≥3 and F4 were 0.760, 0.846 and 0.873, respectively. The diagnostic sensitivity and specificity were 64.15%, 92.31%, 77.78%, 80.00% and 88.46, 72.50%, respectively. Conclusion MRI-ECV imaging has great value for staging hepatic fibrosis of hepatitis B, and it can provide an effective method for diagnosis, staging, and evaluating the curative effect of fibrosis.

Objective To analyze MR imaging appearance of pancreatic neuroendocrine neoplasms (pNEN) and to investigate the practical value of MR imaging appearance in predicting pathological grade of pNEN. Methods All data of 35 patients with pathologically proven pNEN were retrospectively reviewed. MR examinations of the abdomen were performed on all these patients before operation and the data of clinical, pathological and MR imaging were intact. Both plain scan and contrast-enhanced MR scan were performed on each patient. Histopathological grade of pNEN was defined as: G1, G2, and G3 according to World Health Organization classification of tumours of the digestive system guidelines(2010). Image analysis included tumor location, number, size, shape, lesion margins, signal intensity, enhancement pattern, main pancreatic duct dilatation, extrapancreatic spread, and metastases of lymph node and liver. The comparison of quantitative index between G1 and G2 group was performed with t test. Categorical variables were tested using Fisher exact test. Results Thirty five lesions were found in 35 patients, with 14 lesions in G1, 19 lesions in G2, and 2 lesions in G3.Thirty three lesions appeared as a solid mass, and 2 lesions appeared as a cystic lesion. Significant gender-based difference was found between G1 group and G2 group (P<0.05). No significant age-based or endocrine function difference was found between the G1 group and G2 group(P>0.05). Of the 35 lesions, 27 lesions were round in shape, while other 8 lesions were irregular. There were 18 lesions with clear margin, and the margins in other 17 lesions were blurred. Main pancreatic duct dilatation was found in 3 cases(1 in G2, 2 in G3). Significant differences in tumor diameter, shape, margin, signal intensity on precontrast images, extrapancreatic spread and metastases were found between G1 group and G2 group(P<0.05). No significant difference was found in main pancreatic duct dilatation or signal intensity on all enhancement phases between G1 group and G2 group. The 2 lesions in G3 group appeared mild contrast enhancement with degrees lower than the pancreas in all enhancement phases. Conclusion MR imaging features such as tumor diameter, shape, margin, signal intensity on precontrast images, extrapancreatic spread and metastases may preoperatively predict the pathological graden of pNEN.

OBJECTIVE: To compare the diagnostic accuracy of intravoxel incoherent motion (IVIM)-derived parameters and apparent diffusion coefficient (ADC) in distinguishing between renal cell carcinoma (RCC) and fat poor angiomyolipoma (AML). MATERIALS AND METHODS: Eighty-three patients with pathologically confirmed renal tumors were included in the study. All patients underwent renal 1.5T MRI, including IVIM protocol with 8 b values (0–800 s/mm²). The ADC, diffusion coefficient (D), pseudodiffusion coefficient (D*), and perfusion fraction (f) were calculated. One-way ANOVA was used for comparing ADC and IVIM-derived parameters among clear cell RCC (ccRCC), non-ccRCC and fat poor AML. The diagnostic performance of these parameters was evaluated by using receiver operating characteristic (ROC) analysis. RESULTS: The ADC were significantly greater in ccRCCs than that of non-ccRCCs and fat poor AMLs (each p < 0.010, respectively). The D and D* among the three groups were significantly different (all p < 0.050). The f of non-ccRCCs were less than that of ccRCCs and fat poor AMLs (each p < 0.050, respectively). In ROC analysis, ADC and D showed similar area under the ROC curve (AUC) values (AUC = 0.955 and 0.964, respectively, p = 0.589) in distinguishing between ccRCCs and fat poor AMLs. The combination of D > 0.97 × 10⁻³ mm²/s, D* < 28.03 × 10⁻³ mm²/s, and f < 13.61% maximized the diagnostic sensitivity for distinguishing non-ccRCCs from fat poor AMLs. The final estimates of AUC (95% confidence interval), sensitivity, specificity, positive predictive value, negative predictive value and accuracy for the entire cohort were 0.875 (0.719–0.962), 100% (23/23), 75% (9/12), 88.5% (23/26), 100% (9/9), and 91.4% (32/35), respectively. CONCLUSION: The ADC and D showed similar diagnostic accuracy in distinguishing between ccRCCs and fat poor AMLs. The IVIM-derived parameters were better than ADC in discriminating non-ccRCCs from fat poor AMLs.
Angiomyolipoma* ; Area Under Curve ; Carcinoma, Renal Cell* ; Cohort Studies ; Diffusion ; Diffusion Magnetic Resonance Imaging ; Humans ; Magnetic Resonance Imaging ; Perfusion ; ROC Curve ; Sensitivity and Specificity

Objective To investigate the MRI features of hepatic IgG4?related inflammatory pseudotumor (IPT). Methods Nine patients with 11 histopathologically proven IgG4?related hepatic IPTs were retrospectively analyzed. The clinical, morphological and MRI signal features on T1WI, T2WI, dynamic?enhanced, and diffusion?weighted imaging were assessed in detail and correlated with pathological findings. The paired t test was used to compare the ADC values of the tumors and the hepatic tissue. Results Hepatic IgG4?related IPT displayed certain MRI features. The dominant lesions were subcapsularly distributed (n=7) with a clear boundary (n=8), which typically showed hypointensity on T1WI (n=11), mild hyperintensity on T2WI (n=8), progressive (n=5) or persistent (n=4) enhancement pattern. Accompanied signs included delayed capsule?like enhancement (n=6) and central nonenhanced areas (n=7). Two lesions showed atypical wash?out pattern with iso or hypointensity on portal and delayed phases. In diffusion weighted imaging, all lesions were hyperintense, and the mean ADC value of the lesions [(1.42 ± 0.36) × 10?3mm2/s] was mildly lower than that of surrounding liver [(1.55±0.31)×10?3mm2/s], although no statistical differences were found(t=0.78, P=0.46). Conclusions Hepatic IgG4?related IPTs display various MRI manifestations. The lesions normally show progressive enhancement pattern with diffuse homogeneous or heterogeneous hyperintensity, accompanied by delayed capsule?like enhancement and central nonenhanced areas.

Gadolinium DTPA ; Humans ; Magnetic Resonance Imaging ; Non-alcoholic Fatty Liver Disease

Objective To investigate the value of susceptibility?weighted imaging (SWI) for characterization of small hepatocellular carcinoma (sHCC) in cirrhotic livers. Methods Two hundred seventy?two patients suspiciousof HCC underwent conventional MR imaging and susceptibility?weighted imaging (SWI). Two hundred and five patients were excluded due to either size larger than 3.0 cm, no cirrhosis or HCC. Finally, a total of 84 hepatocellular nodules in 67 patients were included in this prospective study. There were 22 DNs in 12 cases, 8 DNs with HCC foci in 7 cases, and 54 overt HCCs in 48 cases. Two abdominal radiologists independently evaluated signal intensity and enhancing pattern using conventional MRI set and conventional MRI combining with SWI set. A five?point scale was performed to evaluate diagnostic confidence of HCC. Kappa analysis was performed to assess interobserver agreement of the two sets by two readers.The diagnostic performance and confidence level were compared for each image set,ROC was used to evaluate the diagnostic efficiency.Results Good interobserver agreement was identified with a Kappa value of 0.923 for conventional MRI set and 0.865 for conventional MRI combining with SWI set, respectively. The diagnostic sensitivity, specificity, accuracy, and area under the alternative?free response ROC (Az) were 80.6% and 80.6%, 81.8% and 77.3%, 81.0% and 79.8%, 0.804 and 0.782 using conventional MRI set, and 93.5%and 85.5%, 90.9%and 86.4%, 92.9%and 85.7%, 0.898 and 0.859 using conventional MRI combining with SWI set for reader 1 and reader 2, respectively.The diagnostic confidence level of conventional MRI combining with SWI set for diagnosis of HCC with less than 2 cm in size(n=36) was significantly higher than that of conventional MRI (reader 1, 3.86±0.47 vs 3.40±0.91;reader 2, 3.85±0.57 vs 3.41±0.92;t values were 3.733 and 2.468, P were 0.001 and 0.018).Conclusion SWI can provide additional valuable information and improve diagnostic performance for characterization of sHCC in cirrhotic livers.

Objective To compare the MRI features of hepatic neuroendocrine tumors (NET G1,G2) and neuroendocrine carcinomas (NEC G3),as well as to improve the accuracy in hierarchical diagnosis.Methods Twenty patients with histopathologically proven NET and nineteen patients with histopathologically proven NEC were retrospectively analyzed.The morphological and MR signal features were compared.Results The morphological features of vascular invasion (P ＜ 0.05) and lymphadenectasis or necrosis (P ＜ 0.05),as well as the MR signal features on portal phase (P ＜ 0.05) and delayed phase (P ＜0.05) were different between the NET group and the NEC group;contrast to noise ratios (CNR) were also different between the two groups (x2 =5.14,P ＜ 0.05),CNR of the NEC group on both arterial phase (Z =121.75,P ＜ 0.05) and portal phase (Z =139.31,P ＜ 0.05) were significantly lower than the NET group;ROC analysis of CNR demonstrated an area under the curve of 0.729 (P ＜ 0.05) on portal phase,when the optimal cut-off value of-61.38 was used,a sensitivity of 90.0％ and a specificity of 63.2％ can be achieved.Conclusions MRI plays an important role in the hierarchical diagnosis of hepatic neuroendocrine neoplasms.The signs of vascular invasion,lymphadenectasis or necrosis as well as the MR signal features during dynamic enhanced scanning are of great value in differentiating NETs from NECs.