Background: Bone erosion in the sacroiliac joint (SIJ) is highly specific for the diagnosis of axial spondyloarthritis (axSpA) and may indicate early disease progression. The 3D ultrashort echo time (3D -UTE) technique excels in providing clear contrast between the articular cartilage and the bone cortex interface. Additionally, it is emerging as a promising quantitative tool for detecting early cartilage changes. Therefore, this study aimed to evaluate the diagnostic performance of 3D -UTE sequences in identifying bone erosion in the SIJ of patients with axSpA and to clarify the potential of cartilage T2* values as a quantitative biomarker for axSpA. Methods: This prospective study employed convenience and consecutive sampling methods to recruit patients diagnosed with axSpA in Peking University Third Hospital who met the Assessment of Spondyloarthritis International Society (ASAS) criteria and also an equal number of healthy volunteers. After providing informed consent, all participants underwent 3D -UTE sequences and conventional T2* mapping of the SIJs. Two radiologists separately interpreted the bone erosion of each SIJ on 3D -UTE sequences. Erosion detection of SIJs via computed tomography (CT) served as the standard of reference. The T2* values of the cartilage were measured and compared, and the diagnostic efficacy of the T2* value for axSpA diagnosis was evaluated. Results: A total of 32 patients and 32 healthy volunteers were included. The 3D -UTE sequence, as separately assessed by two reviewers in terms of its ability to detect erosions, exhibited a notable level of accuracy. For the two reviewers, the respective diagnostic sensitivities were 94.7% and 92.9%, the specificities were 97.4% and 96.5%, positive predictive values were 96.7% and 95.4%, the negative predictive values were 95.9% and 94.5%, the accuracies were 96.2% and 94.9%, and the areas under the curve (AUCs) were 96.1% and 94.7%. For the detection of erosions, the interreader kappa value was 0.949. The T2* values of the SIJ cartilage were significantly higher in patients with axSpA than in healthy volunteers. The intraobserver intraclass correlation coefficients (ICCs) for T2* measurements ranged between 80.5% and 82.2%. Meanwhile, the interobserver ICCs for UTE -T2* and gradient echo T2* measurements were 81.5% and 80.8%, respectively. The AUCs of the UTE -T2* values for discriminating patients with axSpA from the healthy volunteers of the two readers were 73.3% and 71.6%, respectively. Conclusions: 3D -UTE sequences can be used as a reliable morphological imaging technique for detecting bone erosion in the SIJ. Additionally, UTE -T2* values of the cartilage may offer a quantitative method for identifying patients with axSpA.

目的建立基于骶髂关节MRI影像组学特征和临床参数的联合列线图模型辅助诊断中轴型脊柱关节炎(axial spondyloarthritis,axSpA).材料与方法回顾性分析2019年4月至2021年9月在我院因怀疑axSpA而就诊的204例患者临床及影像资料,其中102例为确诊的axSpA患者,102例为健康对照.对其临床特征先后进行单变量和多变量分析,选择差异具有统计学意义的特征利用机器学习算法构建临床标签.在研究对象骶髂关节MRI的T1WI及脂肪抑制T2WI序列图像上勾画感兴趣区域并从中提取放射组学特征,利用组内相关系数、皮尔逊相关系数、最小绝对收缩和选择算子选择相关性较强的特征,采用五种机器学习模型(逻辑回归、随机森林、极端随机树、极端梯度提升、多变量逻辑回归)筛选判断骶髂关节异常的影像组学标签.最终将临床标签和影像组学标签整合,建立列线图模型.结果筛选的临床标签为C反应蛋白和红细胞沉降率.从骶髂关节T1WI和脂肪抑制T2WI序列图像中分别提取了1834个影像组学特征,在合并两个序列的特征后,最终共得到3368个特征,从中筛选相关性较高的特征.基于T1WI、脂肪抑制T2WI序列及二者联合的影像组学模型诊断axSpA表现最佳的均为逻辑回归模型,且融合模式的影像组学标签的诊断性能最佳.结合红细胞沉降率与影像组学标签的列线图模型在训练集和测试集诊断axSpA的受试者工作特征曲线下面积分别为0.997(95％置信区间为0.992-1.000)和0.944(95％置信区间为0.889-1.000),表现出了良好的诊断性能.决策曲线也显示列线图模型显示出更好的预测性能和临床应用价值.结论基于骶髂关节MRI影像组学特征和临床参数的列线图模型能够有效区分axSpA患者和健康对照组,有助于临床决策过程.

目的 探讨一分钟教学法(one minute preceptor,OMP)在放射科住院医师规范化培训教学阅片中的应用效果.方法 选取北京大学第三医院放射科参加规范化培训的住院医师,将 2020 年的 15 名学生作为对照组,2021 年的 16 名学生作为试验组.在以案例为基础的教学法(case-based learning,CBL)的前提下,试验组增加 OMP.通过"问卷星"微信平台制作调查问卷,课后采用问卷调查两组学生对当前教学阅片方式的评价,同时比较两组学生影像读片和理论考试成绩.结果 试验组读片考试平均成绩为 88.25±4.36 分,显著高于对照组(82.00±6.40 分),差异有统计学意义(P<0.05);试验组理论考试平均成绩为 85.63±11.69 分,对照组为 81.33±8.06 分,差异无统计学意义(P = 0.247).结论 OMP 结合 CBL 的模式可以提高放射科住院医师规范化培训中的教学阅片效果.

Background Identifying axial spondyloarthritis (axSpA) activity early and accurately is essential for treating physicians to adjust treatment plans and guide clinical decisions promptly. The current literature is mostly focused on axSpA diagnosis, and there has been thus far, no study that reported the use of a radiomics approach for differentiating axSpA disease activity. In this study, the aim was to develop a radiomics model for differentiating active from non-active axSpA based on fat-suppressed (FS) T2-weighted (T2w) magnetic resonance imaging (MRI) of sacroiliac joints. Methods This retrospective study included 109 patients diagnosed with non-active axSpA ( n = 68) and active axSpA ( n = 41); patients were divided into training and testing cohorts at a ratio of 8:2. Radiomics features were extracted from 3.0 T sacroiliac MRI using two different heterogeneous regions of interest (ROIs, Circle and Facet). Various methods were used to select relevant and robust features, and different classifiers were used to build Circle-based, Facet-based, and a fusion prediction model. Their performance was compared using various statistical parameters. p < 0.05 is considered statistically significant. Results For both Circle- and Facet-based models, 2284 radiomics features were extracted. The combined fusion ROI model accurately differentiated between active and non-active axSpA, with high accuracy (0.90 vs.0.81), sensitivity (0.90 vs. 0.75), and specificity (0.90 vs. 0.85) in both training and testing cohorts. Conclusion The multi-ROI fusion radiomics model developed in this study differentiated between active and non-active axSpA using sacroiliac FS T2w-MRI. The results suggest MRI-based radiomics of the SIJ can distinguish axSpA activity, which can improve the therapeutic result and patient prognosis. To our knowledge, this is the only study in the literature that used a radiomics approach to determine axSpA activity.

目的 探讨微信辅助以问题为导向的教学法(problem-based learning,PBL)结合以案例为基础的教学法(case-based learning,CBL)在放射科住院医师规范化培训中的应用效果.方法 选取笔者科室参加规范化培训的住院医师 38 人,随机分为实验组和对照组,实验组采用 PBL结合 CBL 的教学模式,对照组采用传统教学模式,进行 20 学时的影像诊断教学.通过"问卷星"微信平台制作调查问卷,课后采用问卷调查两组学生对当前实施教学模式的评价,同时比较两组学生影像读片的考试成绩.结果 通过 PBL结合 CBL的教学,学生的学习兴趣、文献检索能力、自学及独立思考能力、临床思维能力、影像诊断能力得到提高.此外,实验组读片考试平均成绩为 84.37±1.01 分,显著高于传统教学组 80.05±1.10 分(P<0.05);实验组理论考试平均成绩为 86.71±5.96 分,传统教学组为 82.96±7.67 分,差异无统计学意义(P =0.100).结论 PBL 结合 CBL 的教学模式可以提高放射科住院医师规范化培训的教学效果.

目的 探讨高原肺水肿(HAPE)的CT影像表现.方法 回顾性收集100例HAPE患者的临床及影像学资料,分析HAPE的分布、形态、密度、是否合并胸腔积液及心脏增大等其他影像学特征.结果 100例HAPE患者,平均进藏时间为6.2 d,男83例,女17例,性别比例有显著差异(P<0.0001).79例HAPE表现为双肺多发磨玻璃密度影伴小结节及实变影,显著多于其他类型病变的总和(P<0.0001).97例患者表现为双肺病变不对称,右肺重于左肺的患者81例,显著多于左肺重于右肺及双肺病变基本对称的患者(P<0.0001).其他胸部CT征象包括小叶间隔增厚、空气支气管征、代偿性肺气肿及树芽征.仅4例患者合并右侧胸腔积液,所有患者均无心脏增大.结论 HAPE患者的胸部CT表现主要为双肺多发不对称的磨玻璃密度影伴小结节及实变影.

目的 探讨胸部节细胞神经瘤(GN)的CT、MRI影像学特征.方法 回顾性分析17例经手术病理证实的胸部GN的临床及影像学资料.所有患者在手术前均行CT和/或MRI扫描,分析病变的位置、形态、大小、密度/信号,边界、病变内部情况、强化方式等影像学表现.结果 17例病变中,15例位于后纵隔脊柱旁,2例位于肺尖近顶胸膜处.10例形态规则,7例“伪足样”生长,15例肿瘤长径平行于人体长轴.CT平扫多为均匀软组织密度,4例伴钙化,2例伴脂肪密度,增强扫描无或不均匀轻度强化.T1WI呈等或稍低信号,T2WI不均匀稍高/高信号,8例内见条索状低信号,增强扫描动脉期元或轻度强化,延迟期渐进性轻至中度强化.结论 胸部GN的主要影像学表现为边界清楚、形态规则或“伪足样”生长的软组织肿物,CT密度均匀,T2WI不均匀高信号,增强扫描动脉期无或轻度强化,延迟期渐进性强化.

目的 探讨创伤相关性膝关节髌下脂肪垫病变的MRI表现.方法 回顾性选取45例经临床和/或关节镜证实的创伤相关性膝关节髌下脂肪垫病变,分析不同病变的发生部位、形态及MRI信号特点.结果 45例创伤相关性膝关节髌下脂肪垫病变中,Hoffa氏综合征8例,髌腱-股骨外侧髁摩擦综合征9例,关节镜术后髌下脂肪垫纤维化10例,Cyclops病变18例.Hoffa氏综合征MRI表现为髌下脂肪垫中央部水肿,多伴有纤维化,可同时伴有髌下脂肪垫增大、出血.髌腱-股骨外侧髁摩擦综合征均表现为髌下脂肪垫上外侧部水肿,部分病例伴有髌腱炎或髌骨高位.关节镜术后髌下脂肪垫纤维化主要表现为斜行穿过髌下脂肪垫的带状低信号影.Cyclops病变位于股骨髁间窝前交叉韧带植入物的前方,T1 WI呈等(和)或低信号,质子密度加权成像(PDWI)多呈以低信号为主的混杂信号.结论 创伤相关性膝关节髌下脂肪垫病变MRI多表现为特定部位的髌下脂肪垫水肿和/或纤维化,MRI能够用于鉴别不同类型的髌下脂肪垫病变.

BACKGROUND:Our study aimed to characterize the imaging appearance of spinal fractures in ankylosing spondylitis (AS) and identify situations in which the use of magnetic resonance imaging (MRI) is necessary.METHODS:A total of 70 cases of spinal fractures associated with AS were retrospectively enrolled. Two radiologists independently reviewed the preoperative images. The location, type, ligament injury, neurological injury, and epidural hematoma following spinal fractures were assessed.RESULTS:Only one patient had a vertebral compression fracture, and 69 patients had 77 transverse fractures involving three columns. The most frequent injuries in AS patients were type B3 (N=32, 43.8%) spine fractures, followed by type C (N= 20, 27.4%) spine fractures. There were significant differences in fracture types of the different spine regions (H=14.1, P<0.0001). Most type C spine fractures were located in the lower cervical spine, while most of the type B2 spine fractures were located in the thoracic spine. Transverse fractures were classified as shear or stress type fractures. In total, there were 62 shear fractures and 15 stress fractures. All of the transverse fractures were detected by computed tomography (CT). The accuracy of CT in the diagnosis of the exact anatomic involvement of transverse fractures was significantly higher than that of MRI (χ2=8.36, P=0.014). The anterior longitudinal ligament (ALL) was the most frequently torn ligament. Tears of ossified ligaments were best visualized by sagittal reformatted CT. Lower cervical fractures were more likely to be associated with neurological injury compared with fractures to other regions of the spine (χ2=7.24, P=0.025). There were six epidural hematoma cases, which were only detected by MRI, were found to have fractures of the lower cervical spine.CONCLUSIONS:We recommend a whole-spine CT examination with three-dimensional reconstruction for detecting a suspected fracture in AS patients. In cases with neurological injury, MRI examinations are always mandatory. AS patients with lower cervical spine fractures require further investigation by MRI. Patients with non-lower cervical spine fractures without any neurological deficits do not need to undergo an immediate MRI.

目的 探讨原发性肺结外NK/T细胞淋巴瘤(ENKTCL)的CT表现,提高影像诊断的准确性.方法 回顾性分析经病理证实的5例原发性肺ENKTCL的CT征象.5例患者均行胸部CT检查,分析病变部位、数目、分布、形态、大小、密度、边界、病变内部情况、强化特点、纵隔及肺门淋巴结肿大、胸腔积液等.结果 5例患者肺部病变均为双侧多发,主要表现为结节、肿块、斑片状实变及磨玻璃密度影,以结节最多见(5/5),3例同时存在不同病变.3例部分病变周围可见晕征.5例患者均未见明显坏死或空洞,3例实变内可见空气支气管征.3例行增强扫描,病变轻度均匀强化,其中1例可见"血管造影征".5例患者均未见纵隔或肺门淋巴肿大,4例伴有胸腔积液.结论 原发性肺ENKTCL影像学表现主要为双肺弥漫或多发结节、肿块和/或实变、磨玻璃密度影,伴或不伴胸腔积液.

目的 探讨膝关节弥漫性滑膜病变的MRI诊断及鉴别诊断.方法 回顾性选取87例经病理明确诊断的膝关节滑膜病变,分析其MRI表现,比较不同疾病的滑膜信号特点、滑膜增厚程度、膝关节骨质侵蚀、骨髓水肿及强化方式的差异.结果 87例膝关节滑膜病变中,弥漫型色素沉着绒毛结节性滑膜炎(PVNS) 31例,类风湿性关节炎(RA)20例,滑膜结核(STB)9例,滑膜软骨瘤病(SC) 27例.弥漫型PVNS在脂肪抑制质子密度加权成像(PDWI)上滑膜信号最低,PVNS及SC的滑膜增厚程度显著高于其他疾病,P＜0.000 1.STB引起的骨质侵蚀范围最大,P＜0.000 1.STB及RA骨髓水肿范围显著高于PVNS及SC,P＜0.000 1.增强扫描不同病理类型的增生滑膜均表现为不均匀明显强化.结论 膝关节弥漫性滑膜病变在MRI上均表现为不同程度的滑膜增厚,增生滑膜的信号特点、骨质侵蚀及骨髓水肿程度的差异,在一定程度上有助于鉴别不同性质的滑膜病变.

目的:探讨能谱CT定量参数评价晚期非小细胞肺癌(NSCLC)化疗近期疗效的临床应用价值.方法:前瞻性搜集34例拟行化疗的晚期非小细胞肺癌患者,在化疗前、后均行能谱CT双期增强扫描,测量治疗前、后病变在动脉期(AP)和静脉期(VP)的CT值、能谱定量参数值及能谱曲线的斜率(λ).根据RECIST 1.1标准将患者分为两组:有效组(完全缓解及部分缓解)15例和无效组(疾病稳定及疾病进展)19例,比较两组患者治疗前、后病变的强化程度及能谱参数值的差异.将治疗前组间差异有统计学意义的参数纳入logistic回归方程,筛选出对疗效有预测价值的参数,并生成预测化疗有效的新变量(new variable,NV),对进入方程的参数及NV进行ROC曲线分析,并比较其预测化疗疗效的能力.结果:有效组与无效组之间患者的人口学资料、临床分期、肿瘤的病理类型和分化程度的差异均无统计学意义(P>0.05).治疗前有效组的动脉期和静脉期标准化碘浓度(NICAP、NICVP)、能谱曲线斜率(λAP、λVP)均高于无效组(15.53±4.34 vs.12.20±4.00,32.86±7.96 vs.23.29±6.03,2.26±0.65 vs.1.81±0.47,2.49±0.52 vs.1.85±0.40;P均<0.05).有效组治疗后NICAP、NICVP均较治疗前降低(12.64±3.80 vs.15.53±4.34,27.09±7.48 vs.32.86±7.96;P均<0.05).治疗前NICVP及λVP进入Lo-gistic回归方程,NICVP、λVP和NV预测进展期NSCLC化疗疗效的ROC曲线下面积(AUC)分别为0.832、0.823和0.898,两两比较结果显示3个参数之间AUC的差异均无统计学意义(P>0.05).结论:NICVP及λVP值能够预测晚期NSCLC化疗疗效,两者联合可以提高预测效能.

OBJECTIVE:To validate the value of dual energy CT (DECT) in the differentiation of mediastinal metastatic lymph nodes from non-metastatic lymph nodes in non-small cell lung cancer (NSCLC).METHODS:In the study, 57 surgically confirmed NSCLC patients who underwent enhanced DECT scan within 2 weeks before operation were enrolled. Two radiologists analyzed the CT images before operation. All mediastinal lymph nodes with short diameter≥5 mm on axial images were included in this study. The morphological parameters [long-axis diameter (L), short-axis diameter (S) and S/L of lymph nodes] and the DECT parameters [iodine concentration (IC), normalized iodine concentration (NIC), slope of spectral hounsfield unit curve (λHU) and effective atomic number (Zeff) in arterial and venous phase] were measured. The differences of morphological parameters and DECT parameters between metastatic and non-metastatic lymph nodes were compared. The parameters with significant difference were analyzed by the Logistic regression model, then a new predictive variable was established. Receiver operator characteristic (ROC) analyses were performed for S, NIC in venous phase and the new predictive variable.RESULTS:In 57 patients, 49 metastatic lymph nodes and 938 non-metastatic lymph nodes were confirmed by surgical pathology. A total of 163 mediastinal lymph nodes (49 metastatic, 114 non-metastatic) with S≥5 mm were detected on axial CT images. The S, L and S/L of metastatic lymph nodes were significantly higher than those of non-metastatic lymph nodes (P < 0.05). The DECT parameters of metastatic lymph nodes were significantly lower than those of non-metastatic lymph nodes (P < 0.05). The best single morphological parameter for differentiation between metastatic and nonmetastatic lymph nodes was S (AUC, 0.752; threshold, 8.5 mm; sensitivity, 67.4%; specificity, 73.7%; accuracy, 71.8%). The best single DECT parameter for differentiation between metastatic and nonmetastatic lymph nodes was NIC in venous phase (AUC, 0.861; threshold, 0.53; sensitivity, 95.9%; specificity, 70.2%; accuracy, 77.9%). Multivariate analysis showed that S and NIC were independent predictors of lymph node metastasis. The AUC of combined S and NIC in the venous phase was 0.895(sensitivity, 79.6%; specificity, 87.7%; accuracy, 85.3%), which were significantly higher than that of S (P < 0.001) and NIC (P=0.037).CONCLUSIONS:The ability of quantitative DECT parameters to distinguish mediastinal lymph node metastasis in NSCLC patients is better than that of morphological parameters. Combined S and NIC in venous phase can be used to improve preoperative diagnostic accuracy of metastatic lymph nodes.

Background Coronavirus disease 2019 (COVID-19) pneumonia caused similar symptoms to other community-acquired pneumonia (CAP). It is important to early quarantine suspected patients with COVID-19 pneumonia from patients with other CAP to reduce cross infection. The purpose of the study is to review and compare initial thin-section computed tomography (CT) features in patients with coronavirus disease 2019 (COVID-19) pneumonia and other community-acquired pneumonia (CAP). Methods 24 cases of COVID-19 pneumonia (14 males and 10 females; age range, 14-87 years; mean age, 48.0 years) and 28 cases of CAP caused by other pathogens (13 males and 15 females; age range, 24-85 years; mean age, 49.5 years) were included. Thin-section CT features of the lungs for all patients were retrospectively reviewed by two independent radiologists. Results There were no significant differences for the shape of main lesions, pure ground glass attenuation (GGA), mixed GGA with consolidation, air bronchogram, linear opacities, halo sign/reversed halo sign, cavitation and lymphadenopathy between the group of COVID-19 pneumonia and the group of other CAP. However, the frequency of crazy-paving appearance, vessel dilatation, bilaterally involvement and peripherally distribution were significantly higher in patients with COVID-19 compared with other CAP ( p =0.031, p =0.000, p =0.029 and p =0.009, respectively). Conversely, the frequencies of pure consolidation, tree-in-bud sign and pleural effusion were significantly higher in patients with CAP than in patients with COVID-19 pneumonia ( p =0.002, p =0.000 and p =0.048, respectively). Conclusion There are considerable overlaps in thin-section CT features between COVID-19 pneumonia and other CAP. However, the presence of crazy paving pattern, vessel dilation, bilateral involvement and peripheral distribution contributes to the diagnosis of COVID-19 pneumonia. While the presence of pure consolidation tree-in-bud sign, pleural effusion can be assisting in exclusive the diagnosis of COVID-19 pneumonia.

Objective:To explore the value of X-ray signs with applying low dose of contrast agent to confirm successful puncture in direct shoulder MR arthrography.Methods:In total 669 patients who underwent shoulder MR arthrography in Peking University Third Hospital from January 2016 to August 2018 were retrospectively analyzed. All patients received the anterior approach puncture in shoulder arthrography. X-ray films were taken after 1-2 ml contrast agent was injected. Six X-ray signs of contrast agent distribution were recorded. MR arthrography findings were used to confirm whether the puncture was success. Kappa analysis was used to verify the consistency between each 2 signs. The accuracy rate of each X-ray sign to confirm the successful puncture was calculated. X-ray signs were paired to define the best diagnostic index of successful puncture.Results:Successful puncture was performed in arthrographies for all 669 cases .The displaying rates of six signs were as follows. Contrast agent distribution at overlapping humeral head away from the needle was 66.8% (447/669), in axillary recess was 64.7% (433/669), in glenohumeral space was 93.9% (628/669), in subscapular bursa was 69.8% (467/669), in sheath of long head tendon of biceps brachii (LHBT) was 1.9% (13/669), between LHBT and supraspinatus tendon was 17.2% (115/669). Consistency of each 2 signs was poor (Kappa<0.2), in which the poorest consistency was found between contrast agent overlapping humeral head away from the needle and contrast agent in glenohumeral space (Kappa=-0.115). With combining the above 2 signs, the accuracy rate for defining successful puncture was 100% (669/669).Conclusion:In direct shoulder arthrography by anterior approach, X-ray signs with low dose of contrast agent can be regard as the method to confirm successful puncture. The accuracy rate of the signs of contrast agent distribution at overlapping humeral head away from the needle or in glenohumeral space to define a successful puncture is 100%.

目的 探讨基于影像存储与传输系统(PACS)的案例教学法(CBL)在医学影像诊断见习中的应用效果.方法 选取2017年5～6月北京大学第三医院2013级临床方向八年制学生52名,按照随机数字表法分成实验组和对照组,每组26名.实验组采用基于PACS系统的CBL教学法,对照组采用传统教学法,两组均进行10学时的骨关节系统影像见习课.课后采用问卷调查两组学生对当前实施教学模式的评价,比较两组学生骨关节系统读片的考试成绩.结果 实验组调查问卷中对教学模式的满意度,以及认为该模式有助于促进对理论知识的理解、提高自学及独立思考能力、培养交流及表达能力、提高临床思维能力、读片能力的评分均显著高于对照组(P<0.01),实验组的平均考试成绩高于对照组,差异均有统计学意义(P<0.05).结论 基于PACS系统的CBL教学法,是一种科学有效的教学模式,可以提高影像诊断见习课的教学效果.

目的:探讨非四肢滑膜肉瘤的CT、MRI影像学特征.方法:回顾性分析20例经病理证实的非四肢滑膜肉瘤的临床及影像学资料.所有患者在治疗前均行CT和/或MRI扫描,分析病变的位置、大小、形态、密度/信号、边界、强化方式、邻近软组织、骨质破坏及远处转移的影像学表现.结果:20例滑膜肉瘤中病变位于脊柱、胸部、腹盆腔、腹股沟区的例数分别为7、6、5、2例.肿瘤体积较大,其中14例肿瘤最大径＞5 cm;15例肿瘤呈类圆形,5例呈不规则形;7例病灶为实性,13例为囊实性;17例病变密度/信号不均匀.其他影像学征象包括肿瘤内出血2例,钙化5例,囊变/坏死13例,肿瘤周围软组织水肿7例,骨质破坏8例.15例患者行MRI检查,其中7例可见“三重信号征”.增强扫描2例直径≤5 cm的滑膜肉瘤呈均匀明显强化,其余均呈不均匀明显强化.9例患者发生远处转移,其中7例发生胸膜及肺转移,2例发生腹腔转移.结论:滑膜肉瘤的影像学表现具有一定的特征性,尤其是MRI表现特征具有重要的诊断价值.

To evaluate the utility of mono-exponential and bi-exponential model-based diffusion-weighted MR imaging and IDEAL-IQ sequence for differentiating the activity of sacroiliitis in ankylosing spondylitis (AS). AS patients were divided into active group (n = 30) and inactive group (n = 28) according to Ankylosing Spondylitis Disease Activity Score (ASDAS) with C-reactive protein (CRP). In addition, 30 healthy volunteers were chosen as healthy group. Subjects were scanned by conventional MRI, diffusion-weighted imaging, and IDEAL-IQ sequence. Apparent diffusion coefficient (ADC), true diffusion coefficient (D), pseudodiffusion coefficient (D*), perfusion fraction (f), and fat fraction (FF) values were measured, and their relative values (rADC, rD, rD*, rf) were calculated by the formula ADC (D,D*,f)lesion/ADC (D,D*,f)reference, respectively. The ADC, D, rADC, and rD of active group were the highest among the three groups, followed by inactive and healthy group. However, D* and rD* showed no significant difference among the three groups. FF was significantly higher in inactive group than in healthy and active group. ADC and D had significantly higher AUCs than f for differentiating active group from healthy group, while FF had the highest AUC for distinguishing inactive sacroiliitis from healthy group. DWI and IDEAL-IQ imaging are helpful in quantitatively assessing the activity of sacroiliitis in AS patients.

Objective To investigate the clinical value of diffusion-weighted imaging (DWI) for evaluating the activity of sacroiliitis in ankylosing spondylitis (AS).Methods Totally 73 AS patients were prospectively enrolled and divided into active group (n=43) and chronic group (n=30) according to Bath ankylosing spondylitis disease activity index (BASDAI) scores and laboratory findings. Conventional magnetic resonance imaging (MRI) and DWI were performed in all subjects. Apparent diffusion coefficient (ADC) values of subchondral lesions in sacroiliac joint were independently measured by two radiologists,and the relative ADC (rADC) values were calculated. ADC and rADC values were compared between active and chronic groups. The efficiencies of ADC and rADC values for differentiating the activity of sacroiliitis were analyzed. In addition,the correlation coefficients of ADC values,rADC values,and BASDAI scores were calculated.Results The ADC and rADC values in the active group were (0.667±0.122)×10 -3 mm 2/s and (1.715±0.343)×10 -3 mm 2/s,respectively,which were significantly higher than those of the chronic group [(0.492±0.0651)×10 -3 mm 2/s and (1.289±0.209)×10 -3 mm 2/s,respectively)] (P<0.0001). The agreement of measurement results between two radiologists was good,and all the interclass correlation coefficients were >0.81. The correlation coefficients of ADC value and rADC value with BASDAI scores were 0.82 and 0.80,respectively (P<0.0001). The optimal cutoff values of ADC value and rADC value for differentiating AS activity were 0.545×10 -3 mm 2/s and 1.467×10 -3 mm 2/s,respectively,The specificity was 81.8% for both indicators,and the sensitivity was 92.0% and 88.0%,respectively.Conclusion DWI is helpful in the quantitative assessment of the activity of sacroiliitis in AS patients.

目的 探讨基于微课的翻转课堂教学模式在医学影像诊断学中的应用效果.方法 2016年5～6月选取北京大学第三医院2012级临床八年制学生50名,将其随机分成实验组和对照组,各25名.实验组采用微课+翻转课堂的混合教学方式,对照组采用传统教学方式,进行10个学时的中枢神经系统影像诊断教学.课后采用问卷调查两组学生对当前实施教学模式的评价,同时比较两组学生中枢神经系统读片的考试成绩.结果 通过基于微课的翻转课堂教学,学生的自学能力、沟通能力、知识掌握及运用能力、读片能力得到提高.此外,实验组平均考试成绩为(87.84+0.93)分,显著高于传统教学组[(79.88±2.71)分](P＜0.05).结论 基于微课的翻转课堂教学是一种科学有效的教学模式,可以提高影像诊断学的教学效果.