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Objective To compare the value of standard coronal MRI and multi-planar reconstruction(MPR)images for evaluation of anterolateral ligament(ALL).Methods Data of 130 patients who underwent knee joint MR examination were retrospectively analyzed,including standard coronal MRI and MPR images.ALL were identified on standard coronal MRI and MPR images and classified as fully visible,partially visible or invisible.The visibility of bilateral ALL on both standard coronal MRI and MPR images were compared,while Kappa test was used to evaluate the consistency on both kinds of images.Results Among 130 cases,on standard coronal MRI and MPR images,the left ALL was fully visible in 83 and 93 cases,partially visible in 21 and 12 cases but invisible cases in 26 and 25 cases,respectively,while the right side ALL was fully visible in 66 and 80 cases,partially visible cases in 29 and 15 cases but invisible cases each in 35 cases,respectively.Significant difference of visibility of bilateral ALL were found between standard coronal MRI and MPR images(both P＜0.05),both with excellent consistency(both Kappa＞0.80).Conclusion MPR could display bilateral ALL better than standard coronal MRI.If the scanning conditions for MPR could not be met,standard coronal MRI might be used to evaluate ALL rather accurately.
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ObjectiveTo investigate the value of magnetic resonance imaging-proton density fat fraction （MRI-PDFF） in evaluating hepatic steatosis in patients with chronic hepatitis B virus （HBV） infection. MethodsThe patients， aged >16 years， who visited the outpatient service or were hospitalized in Beijing Tsinghua Changgung Hospital from January 2018 to December 2022 and were diagnosed with chronic HBV infection were enrolled， and all patients underwent MRI examination of the liver in our hospital. The patients were divided into groups based on the presence or absence of liver cirrhosis， and the consistency in PDFF between different hepatic segments was compared between groups. The Kappa consistency test and intraclass correlation coefficient （ICC） were used for consistency analysis. ResultsA total of 76 patients treated with nucleoside analogues were enrolled， among whom 23 （30.26%） had liver cirrhosis. For all patients， the simple arithmetic average of PDFF fluctuated between 1.49% and 30.93%. According to MRI-PDFF ≥5% as the diagnostic criterion for fatty liver disease， there were 29 patients （38.16%） with fatty liver disease among all patients. For all 76 patients， the simple arithmetic average of PDFF was lower than the weighted average of PDFF for the whole liver， and there was no significant difference between the simple arithmetic average of PDFF， the weighted average of PDFF， and the PDFF values of the left and right lobes of the liver （F=0.39， P=0.76）. The consistency test showed that the PDFF values of each hepatic segment and the left and right lobes of the liver had strong consistency with the weighted average and simple arithmetic average of PDFF， with an ICC of >0.75， but the consistency between the PDFF value of the right lobe and the weighted average of PDFF was higher than that between the PDFF value of the left lobe and the weighted average of PDFF. In the consistency test of differentiating fatty liver disease in patients with liver cirrhosis， there was poor consistency between the PDFF value of segment Ⅶ and the weighted average of PDFF （Kappa=0.39）， with moderate consistency for the left lobe and the Ⅰ， Ⅱ， Ⅲ， Ⅴ， Ⅵ， and Ⅷ segments. For the patients with liver cirrhosis， the lowest consistency was observed between the PDFF value of Ⅶ segment and the weighted average of PDFF for the whole liver， and the highest consistency was observed between the PDFF value of Ⅵ segment and the weighted average of PDFF for the whole liver. For the patients without liver cirrhosis， the lowest consistency was observed between the PDFF value of Ⅱ segment and the weighted average of PDFF for the whole liver， and the highest consistency was observed between the PDFF value of Ⅴ segment and the weighted average of PDFF for the whole liver. ConclusionMRI-PDFF is more comprehensive in evaluating hepatic steatosis in patients with chronic HBV infection， and for the patients with liver cirrhosis， there is poor consistency between the PDFF value of each segment and the weighted average of PDFF.
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Objective:To study the value of imaging features of extrapancreatic nerve plexus in predicting early postoperative recurrence of ductal adenocarcinoma of pancreatic head.Methods:The clinical, imaging and pathological data of patients with ductal adenocarcinoma of pancreatic head undergoing pancreati-coduodenectomy at the Hepatobiliary Pancreatic Center of Beijing Tsinghua Changgung Hospital, Tsinghua University from January 2014 to April 2022 were retrospectively analyzed. A total of 73 patients were included, including 51 males and 22 females, aged (66.1±9.0) years old. The patients were followed up by telephone or outpatient review, who were divided into two groups according to the recurrence within 6 months after surgery: the recurrence group ( n=26) and the non-recurrence group ( n=47). Streaks or soft-tissue densities in the distribution area of extrapancreatic nerve plexus, difference in CT values between the portal and arterial phases of the distribution area of extrapancreatic nerve plexus, maximum tumor diameter, and regional lymph node enlargement were compared between the two groups. Results:The incidences of streaks or soft-tissue densities showing in the distribution area of extrapancreatic nerve plexus were 80.8%(21/26) in the recurrence group and 51.1%(24/47) in the non-recurrence group, respectively. A CT value difference ≥15 HU between the portal and arterial phases of the distribution area of extrapancreatic nerve plexus occurred in 50.0%(13/26) patients of the recurrence group and 25.5%(27/47) of the non-recurrence group, respectively. Maximum tumor diameter ≥25 mm were found in 80.8% (21/26) patients of the recurrence group and 57.4% (27/47) of the non-recurrence group, respectively. ≥3 reginal lymph node enlargement showed in 65.4% (17/26) patients of the recurrence group and 31.9% (15/47) of the non-recurrence group, respectively (all P<0.05). The risk of early postoperative recurrence increased in patients with a CT value difference ≥15 HU between the portal and arterial phases of the distribution area of extrapancreatic nerve plexus ( OR=3.609, 95% CI: 1.099-11.855), and regional lymph node enlargement ≥ 3 ( OR=4.665, 95% CI: 1.400-15.545) (all P<0.05). And these two independent risk factors were combined to predict early postoperative recurrence of ductal adenocarcinoma of pancreatic head with an area under receiver operating characteristic curve of 0.748, sensitivity of 92.3%, and specificity of 48.9% ( P<0.001). Conclusion:≥ 15 HU CT value difference between the portal and arterial phases of the distribution area of extrapancreatic nerve plexus and ≥ 3 regional lymph node enlargement are independent risk factors for the early postoperative recurrence of pancreatic head ductal adenocarcinoma, which could provide more predictive information preoperatively.
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Objective:To investigate the feasibility and clinical value of 4D flow magnetic resonance imaging (MRI) in evaluating hemodynamics of ischemic stroke patients with intracranial artery stenosis.Methods:Ischemic stroke patients with unilateral middle cerebral artery stenosis admitted from March 2017 to June 2018 in Beijing Tsinghua Changgung Hospital Stroke Center were prospectively enrolled. Time of flight magnetic resonance angiography was used to evaluate vascular stenosis, 4D flow MRI was used to measure net forward flow at the proximal of stenosis, and brain tissue perfusion was acquired simultaneously to validate flow.Results:A total of 33 patients with symptomatic middle cerebral artery stenosis were included [mean age: 56 years; male: 63.6% ( n=21)]. The flow rates among patients with stenosis of <30%, 30%-49%, 50%-69% and ≥70% were (3.56±1.08), (2.96±0.94), (3.72±0.60) and (2.50±1.03) ml/s individually, demonstrating a decreased flow in subjects with severe (≥70%) stenosis ( F=4.34, P=0.008). Further analysis about forward flow and brain tissue perfusion showed that the significant negative correlation between absolute flow rate or relative flow rate and relative time to peak could only be established in subjects with poor collateral (collateral score: 0-2), with r=-0.76 and -0.61 individually, both P<0.05. Conclusion:4D flow MRI could be used as a quantitative flow assessment in subjects with intracranial artery stenosis, and its association with distal brain tissue perfusion depends on collateral status.
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Objective:To evaluate the metal artifacts reduction effect of multi-acquisition variable-resonance image combination (MAVRIC-SL) after total knee arthroplasty by comparing with two-dimensional fast spin-echo metal artifact reduction sequence (2D FSE MARS).Methods:A total of 78 patients (101 knees) who underwent total knee arthroplasty in Beijing Tsinghua Changgung Hospital from December 2018 to December 2020 were prospectively collected. All patients underwent 3.0 T MR examination within 2 weeks after surgery. The sequences included axial, sagittal, and coronal 2D FSE MARS and MAVRIC-SL. The ranges of prosthesis artifacts were measured, and the scores of the prosthesis clarity, anatomical structure clarity, and joint effusion diagnosis confidence were evaluated by Likert scale. Paired t test was used to compare the difference of artifact range between 2D FSE MARS and MAVRIC-SL. The Wilcoxon signed rank-sum test was used to compare image quality scores and joint effusion diagnosis confidence scores. Results:In 101 knees, the ranges of prosthesis artifacts in axial, sagittal, and coronal 2D FSE MARS were (63.3±8.5), (60.0±7.4) and (62.1±8.7) cm 2, while those of MAVRIC-SL were (49.5±5.8), (44.1±6.6) and (46.1±7.5) cm 2. The differences were statistically significant ( t=20.021, 21.834, 25.472, all P<0.001). The subjective scores of femoral prosthesis clarity, tibial prosthesis clarity, and anatomical structure clarity of MAVRIC-SL were significantly higher than those of 2D FSE MARS (all P<0.001). Confidence scores of 2D FSE MARS and MAVRIC-SL for diagnosing joint effusion were 2 (1, 3) and 3 (2, 3), respectively, and the difference was statistically significant ( Z=6.549, P<0.001). Conclusion:Compared with 2D FSE MARS, MAVRIC-SL can further reduce the metal artifacts in total knee arthroplasty and improve the diagnostic confidence of joint effusion.
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The sudden outbreak of novel coronavirus 2019 (COVID-19) increased the diagnostic burden of radiologists. In the time of an epidemic crisis, we hoped artificial intelligence (AI) to help reduce physician workload in regions with the outbreak, and improve the diagnosis accuracy for physicians before they could acquire enough experience with the new disease. Here, we present our experience in building and deploying an AI system that automatically analyzes CT images to detect COVID-19 pneumonia features. Different from conventional medical AI, we were dealing with an epidemic crisis. Working in an interdisciplinary team of over 30 people with medical and / or AI background, geographically distributed in Beijing and Wuhan, we were able to overcome a series of challenges in this particular situation and deploy the system in four weeks. Using 1,136 training cases (723 positives for COVID-19) from five hospitals, we were able to achieve a sensitivity of 0.974 and specificity of 0.922 on the test dataset, which included a variety of pulmonary diseases. Besides, the system automatically highlighted all lesion regions for faster examination. As of today, we have deployed the system in 16 hospitals, and it is performing over 1,300 screenings per day.
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Objective To investigate the value of preoperative intravoxel incoherent motiondiffusion weighted imaging (IVIM-DWI) in predicting early recurrence of hepatocellular carcinoma (HCC)after curative hepatectomy.Methods The clinical data of 51 HCC patients who underwent curative hepatectomy at Beijing Tsinghua Changgung Hospital,Tsinghua University from December 2014 to March 2017 were retrospectively analyzed.The study included 45 males and 6 females,aged 56.4 ± 10.1.The patients were divided into the early-recurrence group (21 patients) and the non-recurrence group (30 patients) according to whether there was HCC recurrence within 1 year after curative hepatectomy.The parameters of the lesions were measured and calculated:the apparent diffusion coefficient (ADC) value,true diffusion coefficient (D) value,perfusion-related diffusion coefficient (D *) value and perfusion fraction (f) value.Receiver operating characteristic curves (ROC) were used to evaluate the prediction efficiency of the parameters.Results The ADC and D values of the early-recurrence group were significantly lower than the non-recurrence group.The differences were statistically significant (P ＜ 0.05).In predicting early recurrence of HCC after curative hepatectomy,the ADC values showed the area under ROC was 0.713 (95％ CI:0.572 ～0.855),the sensitivity was 0.857 and specificity was 0.567 when the optimal threshold value was 1.24 × 10-3mm2/s.The D values in predicting early recurrence demonstrated the area under ROC was 0.740 (95％ CI:0.602 ～ 0.877),the sensitivity was 0.905 and specificity was 0.600 when the optimal threshold value was 1.03 × 10-3 mm2/s.Conclusions The ADC and D values of IVIMDWI could provide evidence in predicting early recurrence of HCC after curative hepatectomy.The D values had a higher prediction efficiency.
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Objective To investigate the value of gadobenate dimeglumine (Gd-BOPTA) enhanced MRI in evaluation of reserved liver function.Methods Totally 68 patients were included among 143 patients who underwent Gd-BOPTA en hanced MRI.The enhancement ratios of SNR and CNR of right lobe,left lobe and caudal lobe were calculated on the ima ges from liver acquisition with volume acceleration flex sequence (LAVA-Flex) of hepatobiliary phase.The average values of right and left lobes and of three lobes were calculated and compared.According to Child-TurcottePugh (CTP) classification,the patients were divided into Class A and Class B.Integrated model of end-stage liver disease (iMELD) was applied to divide the patients into iMELD≤30 and iMELD＞30.The differences of SNR and CNR enhanced ratios were com pared,and the relationship between enhancement ratios and iMELD scores was analyzed.Results There were no significant differences in the enhancement ratios of SNR and CNR among each lobe,the average of two or three lobes (all P＞0.05).The SNR and CNR enhancement ratios of Class A were higher than those of Class B (both P＜0.05).The SNR and CNR enhancement ratios of iMELD≤≤30 were higher than those of iMELD＞30 (both P＜0.05).The SNR and CNR enhancement ratios showed negative correlations with iMELD scores (SNR:r=0.29,P-0.02;CNR:r=-0.32,P=0.01).Conclusion The intracellular uptake of Gd-BOPTA decreases with impaired liver function.Measurement of the de gree of parenchymal enhancement of any lobe or the whole liver on the images of Gd-BOPTA enhancement MRI in the hepatobiliary phase might reflect the reserved liver function.
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Objective To summarize MRI features of anterior cruciate ligament graft tear and to explore the differences of MRI findings between acute tear and chronic tear, and compare the diagnostic ability of MRI and clinical examinations for graft tear. Methods MR images of 43 patients (44 knees) with anterior cruciate ligament graft tear(40 complete tear, 4 partial tear)confirmed by secondary arthroscopy were retrospectively analyzed. There were 18 acute tear and 26 chronic tear. Primary and secondary signs reported with conventional anterior cruciate ligament tear were adopted to evaluate graft tear. The exact probability method was used to compare the prevalence difference between various direct and indirect signs and the χ2 test was used to compare the accuracy between MRI and physical examination. Results The primary signs in MR images of anterior cruciate ligament graft tear included graft discontinuity in 13 kness, graft thickening with edematous high signal intensity in 12 knees, decreased slope of graft fibers in 6 kness, graft disappearing in 5 knees, and distinct graft atrophy in 3 knees. The secondary signs included kissing bone contusion in 4 knees, posteriorcruciate ligament buckling in 3 knees, increased anterior tibial displacement in 2 knees, bone contusion of the lateral condyle of femur, and bone contusion of thetibia condyle in 1 knee, respectively. There were no significant differences regarding the proportion of each sign between acute and chronic graft tear. Accuracy of MRI, Lachman test, and anterior drawer test were 87.5%(35/40), 95.0%(38/40)and 95.0%(38/40), respectively, which were all significantly higher than that of pivot shift test(42.5%,17/40) with significant differences(χ2=17.80, P<0.0083). Conclusions MRI is sensitive for diagnosing anterior cruciate ligament graft tear, the primary signs is the main evidence for the diagnosis of ACL graft tear, but it is hard to distinguish acute and chronic graft tear based on MR findings. The diagnostic accuracy has no statistically significant differences among MRI, Lachman test, and anterior drawer test, but they are all higher than pivot shift test.
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Objective To determine the value of MR in the diagnosis of the medial and lateral meniscal posterior root tears.Methods One hundred and twenty one patients underwent arthroscopy and MR of knee examinations were retrospectively reviewed,and all of them did not have the history of knee surgery before the MR examination.MR images were double-blinded,independently,retrospectively scored by radiology residency (doctor 1) and attending radiologist (doctor 2).The likelihood of the meniscus posterior root tear was scored on basis of arthroscopic findings constituted the gold standard.Sensitivity,specificity and accuracy of MR diagnosis of the lateral and medial meniscus posterior root tear by two physicians were calculated,and the consistency of diagnosis results by two physicians was evaluated using the Kappa statistics.Reasons leading to misdiagnosis or missed diagnosis were discussed.Results Thirty three of the 121 patients were diagnosed with meniscus posterior root tears by arthroscopy,including 14 cases of lateral tears and 19 cases of medial tears.The sensitivity,specificity and accuracy in the diagnosis of posterior lateral meniscus root tears (PLMRT) for doctor 1 were 71.4％ (10/14),82.2％ (88/107) and 81.0％ (98/121),respectively,and for doctor 2 were 71.4％ (10/14),86.0％ (92/107) and 84.3％ (102/121).The sensitivity,specificity and accuracy in the diagnosis of posterior medial meniscus root tears (PMMRT) for doctor 1 were 100.0％ (19/19),88.2％ (90/102) and 90.1％ (109/121),respectively,and for doctor 2 were 100.0％ (19/19),95.1％ (97/102) and 95.9％ (116/121),respectively.The Kappa statistics for PLMRT and PMMRT were 0.67 and 0.81,respectively,demonstrating a good interobserver agreement (P＜0.05).The misdiagnosed cases of the PMMRT were 12 for doctor 1 and 5 for doctor 2.There were 4 cases being commonly misdiagnosed by the two doctors,and there were no any missed cases in this study.For the PLMRT,the misdiagnosed cases were 19 for doctor 1 and 15 for doctor 2.Eleven cases were misdiagnosed and 4 were missed by the two physicians.Conclusion MR is a reliable diagnostic tool for detecting posterior root tears of the medial and lateral meniscus.
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Objective To explore the value of 6 commonly-used quantitative measures on crosssectional MR images to diagnose the patellofemoral instability.Methods Clinical data of 32 patients with patellofemoral instability(34 knees) confirmed by arthroscopy surgery were retrospective analyzed.Knee MR imaging at full extension of the knee was performed in them.Their MR images were compared with those of 23 asymptomatic volunteers.Trochlear facet asymmetry,lateral trochlear inclination,trochlear depth,patellar tilt angle,lateral patellar displacement,and tibial tuberosity-trochlear groove distance(TTTG) were measured in transverse fat-suppressed turbo spin-echo proton density-weighted MR images.Independent sample t test or Mann-Whitney U test were used to compare the differences of these measurements.ROC was used to calculate the area under curve(AUC) and to define the diagnostic threshold value of each measure.Results Trochlear facet asymmetry,lateral trochlear inclination,and trochlear depth in patients were 45.0％±9.2％,10.9°±5.0° and(3.7±1.3) mm,while these measurements were 68.0％±10.5％,21.1°±3.4° and (6.3 ± 1.0) mm in volunteers.These measures were significantly lower in patients than those in volunteers (t values were 10.123,10.862 and 9.835,P＜0.01).Patellar tilt angle and lateral patellar displacement were significantly higher in patients than those in volunteers(24.8°±9.0° vs.12.3°±5.2°,7.36 mm vs.-3.93 mm,t value and Z value were-7.657 and-6.953,P＜0.01).TTTG showed no significant difference between the 2 groups(P=0.798).AUC of trochlear facet asymmetry,lateral trochlear inclination,trochlear depth,patellar tilt angle,and lateral patellar displacement were 0.957,0.957,0.947,0.921 and 0.961,respectively.The recommended diagnostic threshold values for these 5 measures were＜55％,＜15°,＜5 mm,＞17° and＜3 mm,respectively.The sensitivity for these five measurements were 91.2％ (31/34),85.3％ (29/34),91.2％ (31/34),82.4％ (28/34) and 79.4％ (27/34),respectively.The specificity for these five measures were 91.3％ (42/46),97.8％ (45/46),89.1％ (41/46),89.1％ (41/46) and 100.0％ (46/46),respectively.AUC of TTTG was 0.520.Conclusions At full extension of the knee,trochlear facet asymmetry,lateral trochlear inclination,trochlear depth,patellar tilt angle and lateral patellar displacement are all effective in evaluating patellofemoral instability.The diagnostic value of TTTG is relatively poor.
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Objective To evaluate the contrast-enhanced 3D sampling perfection with application-optimized contrasts by using different flip angle evolutions-short TI inversion recovery sequence (SPACE-STIR) for the imaging of the post-ganglionic segments of the brachial plexus.Methods Forty-three patients with suspected brachial plexus lesions were examined with 3D SPACE-STIR and contrast-enhanced 3D SPACE-STIR prospectively.Signal-to-noise ratios (SNR),contrast-to-noise ratios (CNR),and the conspicuousness of roots,trunks,divisions and cords of the brachial plexus of the two 3D sequences were retrospectively compared.Statistical analysis was performed by using student t-test and Wilcoxon rank sum test.Results Compared with 3D SPACE-STIR,contrast-enhanced 3D SPACE-STIR provided the similar SNRs (left,37.41 ±7.34 vs 36.27 ±7.66,t =1.574,P =0.123,right,43.85 ±9.56 vs 42.34 ±9.74,t =1.937,P =0.073),but significantly higher nerve-to-muscle CNRs (left,24.01 ± 6.31 vs 26.39 ± 6.95,right,29.31 ± 7.84 vs 31.77 ± 8.85,t =-3.278,-3.278,both P ＜ 0.01) and nerve-to-lymph gland CNRs(left,-0.84 ± 10.51 vs 15.35 ±8.02,right,-8.47 ± 10.85 vs 19.30 ± 10.35,t =-15.984,-15.651,both P ＜0.01).The conspicuousness of roots and trunks on contrast-enhanced 3D SPACE-STIR was significantly better than that on 3D SPACE-STIR (Z =-3.606,-4.472,P ＜ 0.01),while the conspicuousness of divisions and cords was similar(Z =-1.732,-1.414,P =0.083,0.157).The signal intensity of neoplastic lesions on contrast-enhanced 3D SPACE-STIR tended to decrease rapidly,thus the lesion conspicuousness was worse than that on 3D SPACE-STIR.Conclusions Contrast-enhanced 3D SPACE-STIR has obvious advantages in displaying normal brachial plexus and revealing non-neoplastic lesions of the brachial plexus,but may be insufficient for the diagnosis of neoplastic lesions of the brachial plexus.
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Objective To evaluate the diagnostic value of different sequences of magnetic resonance imaging (MRI) in repaired meniscus.Methods From September 2002 to December 2008,118 patients (130 menisci) underwent arthroscopic meniscus suture in our hospital,including 94 males and 24 females,aged from 15 to 50 years (average,25.7t7.5 years).All patients underwent MRI and second-look arthroscopy postoperatively.Different sequences of MRI were taken to evaluate the grade of meniscal signal at repaired site and the slices involved by grade 3 signal.The diagnostic sensitivity,specificity,accuracy,positive predict value (PPV) and negative predict value (NPV) were calculated for each sequence by using second-look arthroscopy as the gold standard.Results The total healing rate was 80.8％ (105/130) by second-look arthroscopy,which was higher than that by different sequences of MRI.The integrated T2 sequence held the highest diagnostic value,and the sensitivity,specificity,accuracy,PPV and NPV were 76.0％,71.4％,72.3％,38.8％ and 92.6％,respectively.According to the second-look arthroscopy result,the menisci were divided into the healed group and unhealed group.In the healed group,28.6％ of cases (30/105) showed grade 3 signal in MRI,which was less than that (76.0％) in the unhealed group.The rate of the new grade 3 signal (8.6％) and the slices involved by grade 3 signal (0.8±1.0) in the healed group were less than those (16.0％ and 3.0±2.0) in the unhealed group.Conclusion The diagnostic value of the integrated T2 sequence is encouraging with high sensitivity,specificity and accuracy.The new grade 3 signal in the repaired meniscus usually implies that the meniscus is not healed.
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ObjectiveTo evaluate multi-slice CT (MSCT) in glenoid bone loss of patients with recurrent anterior shoulder dislocation.Methods MSCT findings of 108 patients with recurrent anterior shoulder dislocation and 12 with single anterior shoulder dislocation were retrospectively studied.The incidence,degrees and locations of glenoid bone losses were recorded.The incidence was analyzed with Fisher exact test.The maximum length,depth and proportion were compared with Wilcoxon rank sum test.ResultsGlenoid bone loss was detected in 91.7％ (99/108)patients with recurrent anterior shoulder dislocation.The proportion of glenoid bone loss was ( 16.0 ± 6.0)％,and the central locations of glenoid bone loss were from 2: 20 to 4: 25 ( mean 3: 20).Sixty-two percent (67/108) patients had bony Bankart lesions in which 58.2％ (39/67) bony fragments were free and 41.8％ (28/67) were adherent to the anterior border of the glenoid cavity.Seventy-five percent (9/12) patients with single shoulder dislocation had anterior glenoid bone loss,and the proportion of glenoid bone loss was ( 15.2 ± 7.1 ) ％.There were no statistical differences of the incidence (P =0.100) and proportion of glenoid bone loss ( P =0.453 ) between the recurrent and single anterior shoulder dislocation.ConclusionsAnterior glenoid bone loss is common in patients with recurrent anterior shoulder dislocation.
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ObjectiveTo investigate the imaging features of anterior cruciate ligament(ACL) graft insufficiency.Methods X-Ray and MR imaging examinations in 24 consecutive patients who had ACL reconstructive graft insufficiency were retrospectively evaluated for tunnel position,osteoarthrosis and its related complications.Follow-up arthroscopy showed 16 graft tears and 8 graft laxities.Fisher exact test was used to compare tunnel malpositions,the proportion of graft tear on MRI and osteoarthrosis between graft tear group and graft laxity group.ResultsTwo malpositions of tibial tunnel and 3 malpositions of femoral tunnel were seen in graft tear group.Three-malpositions of tibial tunnel and 4 malpositions of femoral tunnel were seen in graft laxity group.The proportion of tibial or femoral malposition showed no significant difference between the two groups(P =0.289,P =0.167).In graft tear group,15 complete graft tears were diagnosed correctly,1 partial tear was misdiagnosed as normal on MRI.In graft laxity group,4 grafts were diagnosed as normal and 4 were considered as graft tear on MRI.A significant difference was seen between the two groups (P = 0.028) in the proportion of graft tear diagnosed on MRI.Fourteen osteoarthrosis were seen in graft tear group and 5 in graft laxity group.No significant difference was seen between the two groups ( P =0.289) in the proportion of esteoarthrosis.Conclusion The proportions of tunnel malposition and osteoarthrosis showed no significant difference between the graft tear group and graft laxity group.Most graft tears can be diagnosed accurately on MRI,but some cases of graft laxity may be misdiagnosed for graft tear.
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Purpose To investigate the feasibility of T1 measurement using multi-slice inversion recovery turbo spin echo (IR-TSE) and variable flip angle three-dimensional fast low angle shot (3D FLASH) for full-joint coverage delayed gadolinium enhanced MRI of the cartilage. Materials and Methods MR phantoms using dilated gadolinium solution with different concentrations and ex vivo bovine cartilages were scanned using multi-slice IR-TSE and variable flip angle 3D FLASH sequences and the T1 values were calculated. The referring T1 value were obtained using single slice IR-TSE sequence. Results On phantom study, the correlation coefficiencies between multi-slice IR-TSE, 3D FLASH sequences and single slice IR-TSE was 1.000 and 0.997, respectively, where P<0.001 on ex vivo bovine cartilage study, the T1 values of the trypsin degraded species measured by single-slice, multi-slice IR-TSE and 3D-FLASH were significantly lower than the control species. The correlation coefficiency between single-slice and multi-slice IR-FSE on the control group, the trypsin degraded group and both was 0.821(P=0.012), 0.968(P=0.001), and 0.953(P=0.001) respectively. The correlation coefficiency between single-slice IR-FSE and 3D-FLASH on the trypsin degraded group, control group and both was 0.199(P=0.637), 0.757(P=0.030), and 0.775(P=0.001) respectively, where P<0.001. Conclusion Both Multi-slice IR-TSE and variable flip angle 3D-FLASH sequences can be applied for T1 measurement of the full joint cartilage.
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Objective To evaluate the imaging quality and diagnostic value of different MR sequences for abnormalities of knee cartilage. Methods Three sequences of MR, including double echo steady state (DESS), multi echo data imagine combination (MEDIC) and true fast imaging with steady state precession (TrueFISP) were performed in 18 healthy volunteers. Signal-to-noise ratio (SNR) of knee cartilage and contrast-to-noise ratio (CNR) to surrounding tissues were measured and compared. Results SNR of cartilage was the highest in MEDIC sequence imaging, CNR of cartilage-synovia was the highest in DESS sequence imaging among three sequences (P<0.05). Conclusion Compared with the other sequences, DESS seems to be optimal in diagnosis of abnormalities in knee cartilage.
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Objective To observe MRI features of the localized intra-articular form of pigmented villonodular synovitis (PVNS) within the knee joint. Methods Fifteen patients with pathologically proved localized intra-articular form of PVNS were retrospectively reviewed, and the MRI appearances were observed. Results Solitary nodule or mass within the knee joint was detected in all 15 patients. The lesion located in the infra-patellar fat pads in 11 patients. Most lesions were round or oval, with a well-defined margin. The maximum diameters ranged from 2.0 cm to 6.0 cm, with a mean value of 3.1 cm. The signal intensity of these lesions was characteristically heterogeneous on SE T1WI, TSE PDWI, and TSE T2WI, and the whole signal was similar to that of muscles on SE T1WI and TSE PDWI, but a little higher on TSE T2WI. Prominent low signal intensity on T2WI because of deposition of hemosiderin was found within 14 lesions, and 9 of 15 lesions showed characteristically low signal marginal rim. Conclusion MRI features of the localized intra-articular form of PVNS include a well-defined solitary nodule or mass locating in the infra-patellar fat pad, heterogeneous signal intensity, and prominent interior focal low signal or peripheral low signal rim on T2WI.
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Objective To evaluate the diagnostic value of shoulder MR arthrography for superior labral anterior-posterior (SLAP) lesions.Methods A retrospective study was conducted in 137 cases of shoulder MR arthrography confirmed by subsequent shoulder arthroscopy.Two radiologists analyzed all MR examinations independently and the results were compared with those of arthrescopy.The superior labrum was described as normal or torn.In addition, each iabral tear was classified as type Ⅰ-Ⅳ.Type Ⅰ lesions were defined as marked fraying of the articulating surface of the superior labrum; type Ⅱ, avulsion of the labral-bicipital complex from the ghnoid; type Ⅲ, displaced bucket handle tear of the superior labrum; and type Ⅳ, bucket handle tear of the superior labrum with extension into the fibers of the biceps tendon.Sensitivity, specificity, and accuracy were calculated.Kappa values were calculated to quantify the level, of inter-observer agreement.Results SLAP lesions were arthroscopically diagnosed in 59 of the 137 patients.Six of the 59 lesions ( 10.2% ) were classified as type Ⅰ , 50 (84.7% ) as type Ⅱ, and 3 (5.1% ) as type Ⅲ.The overall sensitivity, specificity, and accuracy of MR arthrographic detection of SLAP lesions were 86.4% (51/59), 78.2% (61/78), and 81.8% ( 112/137), respectively, for observer A, and 88.1% (52/59), 84.6% (66/78), and 86.1% (118/137), respectively, for observer B.At inter-observer comparison, agreement was very good (Kappa values = 0.796 ).The MR arthrographic classification showed correlation with the arthroscopic classification of SLAP lesions were 83.1% (49/59)and 79.7% (47/59) for two observers, respectively.Conclusion Shoulder MR arthrography is a reliable method for evaluating SLAP lesions.
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Objective To assess the diagnostic value of MRI for the long head of the biceps brachii tendon tear,and to compare the diagnostic efficiency between routing MRI and MR arthrography. Methods A retrospective study was conducted in 215 cases with shoulder MR examination (107 with MR arthrography, and 108 with routing MRI) and subsequent shoulder arthrescopy and surgery. Two radiologists analyzed all MR examinations independently, and the results were compared with those of arthroscopy and surgery. Sensitivity, specificity, and accuracy were calculated. Kappa values were used to quantify the interobserver agreement. Results Based on the results of arthroacopy and surgery, 215 patients comprised 7 cases of complete tear of the long head of the biceps brachii tendon, 29 cases of partial tear, and 179 cases without tear. The overall sensitivity, specificity, and accuracy for the diagnosis of tears (complete and partial tear) of the long head of the biceps brachii tendon were 72.2% (26/36), 91.6% (164/179), and 88.4% (190/215) respectively for observer 1, 80.6% (29/36), 93.8% (168/179), and 91.6% (197/215) respectively for observer 2. The interobserver agreement was good (Kappa value=0.681). For the complete tear of the biceps brachii tendon, the sensitivity, specificity, and accuracy were all 100% (7/7), 100% (208/208), and 100% (215/215) for both observers. For the tear of the long head of the biceps brachii tendon, the accuracy of MR arthrography were 93.4% (100/107) for observer 1 and 96.3% (103/107) for observer 2. They were higher than the Accuracy of routing MRI, which were 83.3% (90/108)and 87.0% (94/108) respectively for two observers (P<0.05). Conclusion Shoulder MRI is a moderate reliable method for evaluating the tear of the long head of the biceps brachii tendon, and the accuracy of MR arthrography is found to be superior to that of routine MRI.