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Objective To assess the value of susceptibility-weighted imaging (SWI) in staging hepatic fibrosis (HF) in rabbits. Methods Sixty healthy rabbits were randomly divided into HF group (n=44), control group (n=16). Rabbits in the HF group and supplementary group were injected subcutaneously with 50%CCl4 oily solution to establish hepatic fibrosis model. On the basis of preliminary test, 8 rabbits in the HF group and 4 rabbits in the control group were selected randomly at the 4th, 5th, 6th, 10th week after CCL4 injection ,respectively , to undergo liver MR scan,including conventional axial T1WI, T2WI and axial SWI, DWI scan. All rabbits were sacrificed after MR scan and the tissue of liver were sampled for pathological test and hepatic fibrosis staging. Rabbits were classified into group F0, F1-2 and F3-4 based on pathological results. Liver signal intensity (SI), and liver-to-muscle SI ratio were measured on SWI images and ADC values were measured on DWI images correspondently. One-way ANOVA analysis was performed to compare difference in liver SI, liver-to-muscle SI ratio and ADC values among group F0 (no fibrosis), F1-2 (mild-moderate fibrosis) and F3-4 (severe fibrosis) . Spearman correlation analysis was performed to correlate pathological staging and liver SI, liver-to-muscle SI ratio and ADC values. Receiver operating characteristic (ROC) curve analysis was performed to compare the diagnostic performance of SWI and DWI for staging HF. Results Two and 5 rabbits in the HF group died at the 5th and the 6th week after CCL4 injection , respectively due to acute hepatic necrosis, hepatorrhexis and systemic failure. Seven rabbits in supplementary group were used as supplement. Of the 16 rabbits in the control group, 1 was excluded from the study due to liver fibrosis. Fifteen rabbits in group F0, sixteen rabbits in group F1-2 and sixteen rabbits in group F3-4 underwent MRI and were included into this study. Liver-to-muscle SI ratio in group F0, F1-2 and F3-4 were 0.973 ± 0.020, 0.880 ± 0.090 and 0.649 ± 0.140, respectively. Liver SI were 378 ± 45, 374 ± 19 and 317 ± 34. ADC values were (1.473 ± 0.320) × 10-3, (1.311 ± 0.310) × 10-3 and (0.942 ± 0.180) × 10-3mm2/s. There were statistically significant differences in liver SI, liver-to-muscle SI ratio and ADC values among group F0, F1-2 and F3-4 (F=46.571,15.803 and 15.317, P< 0.01). Liver-to-muscle SI ratio was highly negatively correlated with HF staging (r=-0.818,P<0.01), while liver SI and ADC values were moderately correlated with HF staging (r=-0.565,-0.630;P<0.01). Area under ROC curve (AUC) of liver-to-muscle SI ratio, liver SI and ADC value for differentiating hepatic fibrosis stage F0 and stage F1-4 were 0.916, 0.695 and 0.768, while the AUC for differentiating hepatic fibrosis stage F0-2 and stage F3-4 were 0.951, 0.904 and 0.900. Conclusion Liver-to-muscle SI ratio on SWI provide added diagnostic value and could be an useful parameter for staging hepatic fibrosis.
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Purpose To assess the clinical application of non-contrast-enhanced MR angiography (NCE-MRA) using flow sensitive dephasing (FSD) prepared steady-state free precession (SSFP) for displaying hand arteries of patients with rheumatoid arthritis. Materials and Methods Twenty-two patients with rheumatoid arthritis were recruited in this study. All the patients undertook hand NCE-MRA and three-dimensional dynamic CE-MRA on a 1.5T MR scanner. The informed consent was obtained from each subject. Image quality was assessed independently by two experienced radiologists at three arterial segments (wrist arteries, palm arteries, andfinger arteries) with a four-point scale. Signal to noise ratio (SNR), contrast to noise ratio (CNR), and vessel sharpness were evaluated by a magnetic resonance physicist. The results and image quality were statistically compared between the two MRA techniques.Results Twenty-two patients of 24 hands successfully underwent NCE-MRA and CE-MRA scan. Among 72 vascular segments, 69 segments of NCE-MRA were diagnostic, which was higher than that of CE-MRA (96% vs 83%,P<0.05). Otherwise, the image quality, SNR, CNR and vessel sharpness of NCE-MRA were all superior to those of CE-MRA (P<0.05).Conclusion NCE-MRA using FSD-prepared SSFP allows clear depiction of the hand arterial tree, and the image quality is superior to that of dynamic CE-MRA. It is a potential tool for evaluating the disease of hand arteries.
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Objective To investigate balanced steady-state free precession with flow-sensitive dephasing magnetization preparation (FSD-bSSFP) in the assessment of arteries of foot in diabetic patients.Methods The lower-extremity peripheral arteries of 43 diabetic patients were evaluated by FSD-bSSFP no contrast MRA and contrast-enhanced MRA (CE-MRA)in. Two experienced observers assessed the image quality, degree of venous contaminated and visibility of pedal artery branches by FSD-bSSFP and CE-MRA respectively in consensus. The signal intensity( SI), signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the source images of both groups were measured and Wilcoxon and t tests were performed. Results The image score of FSD-bSSFP group was 2.7 ± 1.1 and CE-MRA was 2.6 ± 0.8, there was no statistical difference ( Z = 0. 134, P ＞ 0. 05 ). The image score of demonstration of the pedal artery branches and degree of venous contamination on FSD-bSSFP were 3.2 ± 0. 9 and 1.8 ± 0. 4 respectively which were superior to that of CE-MRA (2.5 ± 0.9 and 2.1 ± 0.8 respectively). Significant statistical difference existed between the two groups in demonstration of pedal artery branches ( Z = 5.246, P ＜ 0.05 ) and degree of venous contamination (Z =2.541 ,P ＜0.05). SNR of FSD-bSSFP was 148.6 ±26.7, CNR was 88.3 ± 19.0. SNR of CE-MRA was 148.5 ± 45.6, CNR was 121.0 ± 41.0. No statistical difference existed between SNR between two methods (t = 0.013, P ＞ 0.05 ). But CNR of CE-MRA was superior to that of FSD-bSSFP and significant statistical difference existed between these two methods ( t = 5.113, P ＜ 0.01 ). Conclusion FSD-bSSFP without contrast could be used in the evaluation of foot arteries in patients of renal dysfunction and diabetes.
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Objective To investigate the direct and indirect MRI manifestations of anterior cruciate ligament(ACL)tears and discuss its mechanism and diagnostic value.Methods The study involved 40 patients with ACL tears including 37 males and three females at age range of 16-49 years(mean age of 33 years).Arthroscopy and operation confirmed 28 patients at acute phase of ACL tears,12 at chronic phase of ACL tears,35 with complete ACL tears and five with partial ACL tears.All patients were examined on 1.5T Siemens MRI scanner,with SE,TSE or Medic sequence in multiple directions.The direct and indirect MRI manifestations of ACL tears were retrospectively and statistically analyzed by employing three experienced doctors.Results Among 28 patients with acute tears,the direct MRI signs included signal interruption or non-consecutive(86%),uneven signal(64%)and swelling and thickening ligament(36%).While in 12 patients with chronic teats,the MRI signs manifested swelling ligament(92%),signal interruption or non-consecutive(75%)and uneven signal(58%).The sign of thickening ligament was mainly seen at chronic phase of ACL tears(P ＜0.01).Of 35 patients with complete ACL tears,80% occurred in the middle part of ACL,with low incidence of upper and lower parts.All five patients with partial ACL tears occurred in the anteriomedialis bundle.The indirect MRI signs of ACL tears included 7-shaped deformity of posterior cruciate ligament(PCL)(34 patients,85%),meniscus exposure(26 patients)including 16 with lateral meniscus exposure(62%),bone injury(15 patients)including segond fracture(8 patients,53%),widened joint space(9 patients)including 78% at chronic phase,and tibia antelocation(23 patients,57%).Among 40 patients,37 patients were diagnosed correctly preoperatively,with accuracy rate of 92%.While three patients with partial ACL tears were missed diagnosis preoperatively,with inaccuracy rate of 8%.Conclusion ACL tear is relatively easy to identify preoperatively according to direct and indirect MRI signs in combination with trauma history.