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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 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.
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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.
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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 (P0.05). 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.
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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.
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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 0.97 × 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.
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Humans , Angiomyolipoma , Area Under Curve , Carcinoma, Renal Cell , Cohort Studies , Diffusion , Diffusion Magnetic Resonance Imaging , Magnetic Resonance Imaging , Perfusion , ROC Curve , Sensitivity and SpecificityABSTRACT
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.
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Objective To evaluate the relationship between the T1 relaxation times using gadoxetic acid-enhanced MRI with the organic anion transporter (OATP) and multi-drug resistance protein (MRP) values on colorectal liver metastasis and around normal liver parenchyma.Methods The perspective study included in fifteen patients with liver metastasis from colorectal cancer,who were confirmed colorectal cancer by colonoscopy,liver metastasis by CT scanning and would be underwent liver metastasis surgery.The lesion on the 15 patients was all single.The patients were performed plain scanning,diffusion weighted imaging and dynamic enhancement MRI examination using gadoxetic acid.Besides,for T1 mapping,a dual flip angle three-dimensional gradient echo sequence was performed before and at 20 minutes after gadoxetic acid administration.The reduction rate of T1 relaxation time (ΔT) (before and after gadoxetic-acid administration) of colorectal liver metastasis and around normal liver parenchyma was calculated.The specimens of hepatic metastases and around normal liver parenchyma were obtained during the colorectal liver metastasis operation.After that,they were analyzed by Western-blot and the values on OATP1,OATP8 and MRP2,MRP3 were recorded.The values on OATP1,OATP8 and MRP2,MRP3 and ΔT on hepatic metastases and around normal liver parenchyma were compared with t analysis.The correlation between the sum of the values (hepatic metastases adding around normal liver parenchyma) on OATPI,OATPS,MRP2,MRP3 with T1 relaxation times were calculated by Spearman.Results The scanning images on colorectal liver metastasis using gadoxetic acid MRI examination were as follows:relatively low signal intensity on T1WI; relatively higher signal intensity on T2WI; showing surrounding moderate enhancement on arterial phase and low signal intensity on portal venous phase,delay phase and hepatobililary phase.The values on OATP1,OATP8,MRP2,MRP3 and AT on the hepatic metastases were(0.21±0.09),(0.34±0.21),(0.41±0.22),(0.26±0.14)ng/ml and (33±9)％,respectively.The values on OATP1,OATP8,MRP2,MRP3 and ΔT around normal liver parenchyma were (0.46±0.24),(0.67±0.35),(0.22±0.13),(0.13±0.06) ng/ml and(68±9)％ (t values were 36.37,58.89,24.56,22.52 and 57.16;P＜0.05).The values on patients on OATP1,OATP8,MRP2 and MRP3 [(0.67±0.31),(1.00±0.37),(0.63±0.23),(0.40±0.13)ng/ml,respectively] showed relationship with the values on patients on ΔT(51±9)％ (r values were 0.491,0.432,-0.414 and-0.371;P values were 0.006,0.017,0.023 and 0.040).Conclusion The sum of the values (the hepatic metastases adding around normal liver parenchyma) on OATP1,OATP8,MRP2 and MRP3 showed correlation with the sum of values on the ΔT using gadoxetie acid-enhanced MRI examination,which explained relationship with the quantity of gadoxetic acid absorbed by hepatocyte and the T1 relaxation time on molecular level.
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Objective To investigate the MDCT and dual-energy CT (DECT)features of chromophobe renal cell carcinoma (chRCC)and to improve the diagnostic accuracy before operation.Methods The data of MDCT(46 cases of 47 lesions)and DECT (10 cases )of 56 patients with pathologically confirmed 57 chRCC were retrospectively analyzed.All of them underwent plain scan-ning,corticomedullary phase and parenchymal phase scanning after contrast material injection.The lesions were divided into ≤4 cm group and > 4 cm group according to its maximum diameter.Qualitative and quantitative analysis were compared between the groups.Results 64.9% of chRCCs were round and oval,87.7% of chRCCs were solid or mainly solid tumors.The incidence of hemorrhage,necrosis,calcification,cystic degeneration of the tumors was approximately 38.6%,36.8%,10.5% and 12.3%,respec-tively.Central scar(1 7.5%)and vascular sign (24.6% )were seen in part of chRCCs.The tumors showed iso and high attenuation on plain CT scanning in 47.4% and 45.6% of the lesions,respectively.The enhancement pattern of wash-in and wash-out,prolonged enhancement and delayed enhancement were seen in approximately 24.6%,66.7% and 8.8% of the lesions,respectively.The shape, necrosis and cystic degeneration,vascular sign and density uniformity between the two groups were statistically different.The CT value of the lesions were 37.29 HU,82.58 HU and 78.97 HU on unenhanced,corticomedullary phase and parenchymal phase CT scanning.The lesion-kidney ratio on the three phases was 1.29,0.62 and 0.55,respectively.There was no significant difference be-tween CT values and LKR values.The lesions and its subtle signs were much clearer on the 80 kV images of DECT after contrast in-jection.Conclusion The MDCT and DECT findings of chRCC have certain characteristics.However,when the lesions showed atypi-cal CT findings because of its different degree of enhancement and variable enhancement pattern,it would be very difficult to get an accurate diagnosis and the final results depend on pathological diagnosis.
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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.
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Objective To analyze the computed tomography(CT)and magnetic resonance imaging (MRI)appearances of primary clear cell carcinoma of the liver (PCCCL)and evaluate the value in the diagnosis of the disease.Methods CT and MR images of 38 patients of pathologically confirmed PCCCL were evaluated retrospectively.Twenty-six patients underwent CT,23 underwent MRI, and 1 1 underwent both CT and MRI.Results In pre-contrast CT scanning,24 PCCCLs appeared hypodense and 2 hyperdense.As for MRI 1 9 of the 23 PCCCLs were hypointense and 4 were iso-hypointense on T1 WI.While on T2 WI,22 cases were heterogeneously hyperintense,and 1was iso-hypointense.On the arterial phase of CT/MRI,all cases presented intense enhancement,and on the portal venous phase,35 cases(35/38,92.1%)were relatively hypodense/hypointense and 3 were slightly hyperdense/hyperintense.Among the tumors larger than 3 cm(n=22),nodular enhancement pattern was found in 14 cases(63.6%,14/22).The capsular rim en-hancement was demonstrated in 26 cases.Conclusion PCCCL showed similar dynamic enhancement pattern as common hepatocellu-lar carcinoma,but also depicted specific imaging features.
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Objective To explore the effect on image quality and scanning time by changing parameters and using different scan-ning technique for the clinical application of axial FLAIR pulse sequence.Methods Seven different sets of parameters of T2-FLAIR Pulse Sequences were performed on thirty patients at a 3.0 T MR scanner.Group A was scanned with a routine sequence for refer-ence.Group B,reducing the matrix to 128.Group C,increasing the turbo factor parameter to 24.Group D,setting the contatena-tion to 1.Group E setting the Accel.factor PE to 4.Group F,using a BLADE-FLAIR sequence.Group G,using a HASTE-FLAIR sequence.The SNRs of all images were statistically analyzed by ANOVA among 7 sequences.The image quality of all images was statistically analyzed by Kruskal-Wallis test among 7 sequences.Results The SNR of seven groups of images were 54.69 ±8.12, 1 57.57±25.61,44.56±7.37,38.48 ± 9.32,44.1 9 ±8.79,45.60 ± 6.92,105.20 ± 18.25,respectively(F = 266.368,P =0.000). The scores of image quality were 3.87±0.09,2.50±0.12,3.72±0.1 6,3.10±0.10,1.88±0.10,3.92±0.07,2.08±0.10,re-spectively and the differences among groups were statistically significant(χ2 =1 93.361,P =0.000).Conclusion Suitable turto factor and BLADE technique can be the best option for FLAIR sequence in the head.HASTE-FLAIR sequence can act as the secondary op-tion for the uncooperative patients.
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Objective To investigate rare and atypical imaging manifestations of abdominal lesions associated with IgG4-related disease (IgG4-RD).Methods Forty-one patients with IgG4-RD proved histopathologically or clinically were investigated retrospectively.All the patients underwent precontrast and dynamic enhancement scan of the abdomen.CT was performed in 32 patients and MR imaging in 27 patients (including both of CT and MRI in 18 patients).Whether tissue and organs of the abdomen were involved was observed,especially rare and atypical imaging manifestations including focal pancreatic lesion,pseudocyst and (or) abscess as well as calcification of pancreas,peripheral blood vessels of pancreas involvement and mass-like lesions were existed.Involvement of the organs including liver,gallbladder,spleen,gastrointestinal tract,mesentery and their manifestations were also observed.Results One to four abdominal organs were involved,the numbers of involved organs were as follows:one organ in 13 patients (31.7％),two organs in 12 patients (29.3％),three organs in 13 patients (31.7％),and four organs in 4 patients (7.3％).The most commonly involved organ of the abdomen was the pancreas which was found in 35 patients.Abdominal extrapancreatic lesions were found in 33 patients.Focal involvement of pancreas as a rare manifestation showed in 11 cases (11/35,31.4％).The patterns were focal and multifocal.Rare cases showed pseudocysts (3/35,8.6％) and abscess was found in 1 case.Capsule-like rim was present around the pancreas lesions in 25 cases.Ten cases showed thick and wide rim with unclear boundaries with adjacent blood vessels,and 7 of them showed the peripheral blood vessels surrounded.Bile duct involvement was observed in 26 patients,and gallbladder involvement was observed in only 2 of them.Rare renal involvement patient has mass-like lesion,with hypointensity on T2WI,then showed decreased enhancement and gradually delayed enhancement.One retroperitoneal fibrosis patient also showed mass-like lesion as an atypical and rare manifestation.Three IgG4-related liver inflammatory pseudotumors were found in 2 patients.Lesions showed iso or hypointensity on T2WI,continuously enhancement,with abnormal edge ring.Mesentery involvement was found in 1 patient.Conclusion Several abdominal lesions associated with IgG4-RD have rare and atypical imaging manifestations.There are specific imaging characteristics,which are helpful for most accurate diagnosis of IgG4-RD.
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<p><b>OBJECTIVE</b>To investigate the correlation between magnetic resonance imaging (MRI) characteristics and intrahepatic recurrence of small hepatocellular carcinoma (HCC) after radiofrequency ablation (RFA).</p><p><b>METHODS</b>A total of 34 patients with 39 small HCC who underwent RFA were included in our study.MRI characteristics were compared between the recurrence group and the non-recurrence group; and a subgroup comparison was also made between the solitary recurrence group and the multiple recurrence group.Kaplan-Meier test,t-test/Mann-Whitney U test,Fisher's exact test and F-test were used for statistical analyses.</p><p><b>RESULTS</b>The median follow-up period was 25 (4-45) months and recurrence was observed in 19 (55.9%) of the patients.The 12-and 24-month cumulative recurrence-free survival rates were 71.3% and 51.8%,respectively.The recurrence group had a higher prevalence of lack of tumour capsule before RFA (P =0.017),no or disrupted periablational enhancement within 24 hours after RFA (P =0.012),and a smaller ablative margin (P=0.037).Meanwhile,the average apparent diffusion coefficient value within 24 hours after RFA was higher in the multiple recurrence group (1.57 * 10-3mm2/s) than in the solitary recurrence group (1.34 * 10(-3) mm2/s) (P =0.04).</p><p><b>CONCLUSION</b>MRI can provide early noninvasive findings useful for advanced warning ofintrahepatic recurrence after RFA.</p>
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Humans , Carcinoma, Hepatocellular , Pathology , Catheter Ablation , Kaplan-Meier Estimate , Liver Neoplasms , Pathology , Magnetic Resonance Imaging , Recurrence , Retrospective Studies , Survival Rate , Treatment OutcomeABSTRACT
Objective To investigate the value of syngo WARP technology for spine MR imaging in patients with metallic prosthesis.Methods Twenty-five patients with metallic prosthesis in cervical spine or lumbar spine were prospectively included in this study.Both conventional MR sequences and optimized sequences with syngo WARP were applied in all patients.Acquisition time and image quality of two sequences were compared using a paired t test.Results All patients were examined successfully.Scanning time of cervical spine was 8 min 16 s vs.12 min 45 s for conventional sequences and syngo WARP optimized sequences respectively,with a significant difference (t =7.963,P ＜ 0.01).Scanning time of lumbar spine was longer by syngo WARP optimized sequences compared with conventional sequences (11 min 53 s vs.9 min 16 s),with a significant difference (t =4.904,P ＜ 0.01).However,image quality was better for syngo WARP optimized sequences compared with conventional sequences (4.22 ± 0.67 vs.3.56 ± 0.53 ;t =3.364,P =0.002).STIR with syngo WARP could optimize the signal loss of metallic prosthesis surrounding tissues,and significantly improve image distortion and blurring compared to the conventional sequence.Conclusion Syngo WARP technique could effectively reduce metal artifacts and better display metal implant surrounding tissue and anatomical structure with potential clinical value.
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Objective To evaluate the imaging quality of the non-contrast enhanced MR angiography of sampling perfection with application optimized contrasts using different flip angle evolutions (SPACE)in showing portal system and compared it with that of the contrast enhanced MR angiography of volumetric interpolated breath-hold examination (VIBE),and study its diagnostic ability in the detection of portosystemic and portohepatic collaterals.Methods Thirty consecutively cirrhotic patients with suspected of portosystemic and portohepatic collaterals were enrolled,and underwent SPACE followed by VIBE at 1.5 T MR scanner.The diagnostic accuracy of SPACE for the portal vein disease was evaluated by two doctors and compared it with that of VIBE.The contrast-to-noise ratio(CNR) and signal-to-noise ratio(SNR) of two MRA techniques were compared by using the Wilcoxon signed rank test.The quality assessment including scores of the portal vein segments and overall image quality were used the paired t test.Results Twenty-one patients were diagnosed as portal hypertension,including five types of portosystemic collaterals: esophageal varices (n =5),gastric fundic varices (n =11),splenic varices (n =5),paraumbilical varices (n =5) and cavemous transformation (n =2),and one patient was diagnosed as portal vein tumor thrombus.The diagnostic efficiency of SPACE was equivalent to that of VIBE.In SPACE,the SNR were 291 ± 57,301 ± 74,344 ±76 and the CNR were 231 ±59,242 ±73,286 ±76 at main portal vein,the left branch of portal vein and the right branch of portal vein,respectively.However in VIBE,the SNR were 185 ± 56,176 ± 52,182 ±52 and the CNR were 57 ±23,50 ±21,57± 19 at,respectively.Both SNR and CNR of portal vein segments in the former were better than those in the latter (t values were 7.691,7.418,7.946,15.746,13.508 and 13.880,respectively,P ＜ 0.05).There were no significant difference for the scores of displaying main,left branch and right branch portal vein and overall image quality in VIBE and SPACE (Z values were -1.496,-1.895,-1.496,-2.138,-2.324 and-1.328,respectively,P ＞ 0.05).The scores of displaying the distal branches of left and right portal vein were 2.08 ± 0.78,2.08 ± 0.78 in SPACE,and 1.75 ± 0.53,1.71 ± 0.55 in VIBE,respectively.It was better (Z =-2.138,-2.324,P ＜ 0.05) in SPACE than that in VIBE.Conclusion The SPACE has better visualization of portal vein distal branches than VIBE,and it can be applied for the diagnosis of the portal vein disease.
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Objective To investigate the diagnostic value of different DWI sequences for pancreatic cancer on a 3.0 T MR scanner.Methods Different DWI acquisitions based on SE-EPI sequence were preoperatively performed in 30 patients with pancreatic cancer proven by histopathology on a 3.0 T MR scanner.The patients included 17 males and 13 females.Their age ranged from 39 to 72 years with mean of (57.6 ± 14.9) years.The b values were 0 and 600 s/mm2 and the following sequences were included:breath-hold DWI with MPG pulses in X,Y,Z direction (BH600ALL),breath-hold DWI with MPG pulses in Z direction(BH600SI),respiratory-triggered DWI with MPG pulses in X,Y,Z direction (TRIG600ALL),respiratory-triggered DWI with MPG pulses in X,Y,Z direction and inversion recovery for fat saturation (TRIG600ALL+FS) and free-breathing DWI with MPG pulses in X,Y,Z direction and inversion recovery for fat saturation (FB600ALL+ FS).C,CNR and ADC of pancreatic cancer were caculated and compared among different DWI sequences by statistic mathed.Results CNR (F =11.444,P ＜ 0.001) and C (F =5.447,P ＜ 0.05) of pancreatic cancer displayed noticeably statistical difference among BH600ALL、BH600SI、TRIG600ALL、TRIG600ALL + FS and FB600ALL + FS DWI sequences by ANOVA.Among those five different DWI sequences,the highest CRN of pancreatic cancer was observed in TRIG600ALL and TRIG600ALL + FS(the values were 16.45 ± 10.37 and 13.38 ± 9.10 respectively),while the highest C of pancreatic cancer was noticed in TRIG600ALL + FS (0.39 ±0.15).ADC of pancreatic cancer had no statistical difference among BH600ALL,BH600SI,TRIG600ALL,TRIG600ALL + FS and FB600ALL + FS DWI sequences by Kruskal-Wallis test.For BH600ALL and BH600SI,there were no statistical difference among ADC of pancreatic cancer,adjacent pancreatic tissue and distal pancreatitis by ANOVA.While for all TRIG600ALL,TRIG600ALL + FS and FB600ALL + FS,there were statistical difference among ADC of pancreatic cancer,adjacent pancreatic tissue and distal pancreatitis by ANOVA (F values were 5.353,15.976 and 14.556 respectively,P ＜ 0.05).ADC of pancreatic cancer was statistically lower than that of adjacent pancreatic tissue and distal pancrcatitis on all TRIG600ALL,TRIG600ALL + FS and FB600ALL +FS (P ＜ 0.05).Conelusion Compared to other four DWI sequences,TRIG600ALL + FS had higher C and CNR in pancreatic cancer,and measurement of ADC value was helpful to disclose the histopathological state in pancreatic cancer,adjacent pancreatic tissue and distal pancreatitis.
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Objective To investigate imaging characteristics of multistep hepatocarcinogenesis in cirrhotic livers on susceptibility-weighted imaging (SWI).Methods Seventy-three patients with 83 nodules in cirrhotic livers underwent hepatic MR imaging with SWI.Two radiologists reviewed MR images by consensus.Imaging characteristics of dysplastic nodules (DN),DN with malignant foci and hepatocellular carcinoma (HCC) were evaluated.Prussian blue staining was performed for semiquantification of hepatic iron content and above cirrhosis-associated nodules.Results Positive iron staining of background liver parenchyma was found in 69 of 73 patients and 4 HCC patients showed iron-negative staining of background liver parenchyma.Nine DNs appeared as hypointensity or isointensity with pathologically confirmed similar (n =7) or slightly decreased (n =2) iron deposition compared with background liver parenchyma.SWI detected 14 of 15 DNs with malignant foci.Seven patients appeared as homogeneous hyperintensity and 1 patient appeared as heterogeneous hyperintensity due to intratumoral hemorrhages.The remaining 6 patients demonstrated as nodule-in-nodule appearance with iron deposition in all background nodules,iron deposition with grade 1 in one internal HCC foci,and iron-free in 5 internal HCC foci.The remaining 50 patients with hepatic iron deposition had 55 HCC lesions.Three HCC lesions had iron deposition with grade 1 to 2 and the remaining 52 HCC lesions were pathologically iron-resistant.HCC appeared as hyperintensity compared with siderotic surrounding liver parenchyma.However,HCCs with diameter larger than 3 cm usually demonstrated heterogeneous hyperintensity due to intratumoral hemorrhage.Conclusions SWI could accurately demonstrate dynamic iron depletion on multistep hepatocarcinogenesis in cirrhotic livers.On SWI images,DNs appear as hypointensity due to siderosis and malignant nodules appear as hyperintensity due to iron depletion.
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Objective To evaluate the difference of image quality and lesion detection between Gd+-EOB-DTPA with Gd+-DTPA-enhanced MRI in cases of hepatocellular carcinoma (HCC).Methods A total of 21 HCC patients underwent both Gd+-EOB-DTPA and Gd+-DTPA-enhanced MRI examination,comparing the difference between the two agents using the value of lesion display quality index,sensitivity,specificity,positive and negative predictive value,diagnosis accuracy and CNR.Results There were 25 lesions on the 21 HCC patients with 9 lesions ＜ 1.0 cm.24 lesions showed hypointensity and 1 lesion showed isointensity on hepatobiliary phase with Gd+-EOB-DTPA-enhanced MRI.15 lesions showed hypointensity,5 lesions showed isointensity and 5 lesions showed hyperintensity on portal venous phase with Gd+-DTPA-enhanced MRI.The value of lesion (in particular for the lesion ＜ 1.0 cm)display quality index,sensitivity,specificity,positive and negative predictive value,diagnosis accuracy on Gd+-EOB-DTPA-enhanced MRI and Gd+-DTPA-enhanced MRI were 17scors,89％,89％,89％,89％ and 12 scors,33％,33％,33％,67％ respectively.CNR on hepatobiliary phase with Gd+-EOB-DTPA-enhanced MRI was 639.35.CNR on arterial phase and portal venous phase with Gd+-DTPA-enhanced MRI were 225.25 and 93.25 respectively.The data showed that Gd+-EOB-DTPA-enhanced MRI was better than that of Gd+-DTPA-enhanced MRI.Conclusions Gd+-EOB-DTPA-enhanced MRI displays lesions (especially for lesions ＜ 1.0 cm) better compared with Gd+-DTPA-enhanced MRI increasing the diagnostic accuracy of small HCC.
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Objective To investigate the imaging features of focal nodular hyperplasia and hepatocellular carcinoma on DWI. Methods The data of patients with histopathologically confirmed FNHs and HCCs between August 2008 and November 2010 were collected. A total of 24 patients with 26 FNH lesions and 36 patients with 39 HCC lesions were included in our study. All patients underwent breath-hold DWI with b = 500 s/mm2 and dynamic contrasted-enhanced (DCE) MRI. The imaging findings of FNHs and HCCs were retrospectively analyzed and compared. The signal intensity (SI) of the lesions on DWI were classified as iso-, slightly high, high SI and the distribution of SI between FNHs and HCCs was compared with Fisher exact test. ADC value and lesion-to-liver ADC ratio of FNHs and HCCs were measured and compared by using independent sample t test. ROC was performed to assess the diagnostic value of ADC value and lesion-liver ADC ratio in the characterization FNHs versus HCCs. Results Of 26 FNHs,23 manifested as isointensity or slightly high SI on DWI, but most 25 out of 39 HCCs showed high SI. The distribution of SI between FNHs and HCCs had significant difference ( P = 0. 000). The mean ADC value and lesion-liver ADC ratio for FNHs [ (1.76 ± 0. 62 ) × 10-3 mm2/s and 1.06 ± 0. 18, respectively ] were significantly higher ( P = 0. 001, P = 0. 000, respectively ) than those for HCCs [ ( 1.26 ± 0. 46 ) × 10-3mm2/s and 0. 79 ±0. 12, respectively]. The area (Az) under the ROC for the ADC value and lesionliver ADC ratio for the differentiation of FNHs versus HCCs were 0. 79 ± 0. 05 and 0. 85 ± 0. 05,respectively, with no significant difference (P =0. 270). The specificity of the two measures was 69. 23% and 97.44%, respectively, with significant difference (P = 0. 001 ). Conclusion FNH shows isointensity or slightly high SI with relatively higher ADC value and lesion-liver ADC ratio than those of HCCs on DWI,which is characteristic for its diagnosis and differentiation.