2021年RSNA年会的主题是重塑影像学(Redefining Radiology),旨在探索未来影像的新理念、新技术和新方向.2019年底突如其来的新型冠状病毒肺炎席卷全球,与新型冠状病毒肺炎感染相关的影像学研究成为今年的新增热点.深度学习、人工智能以及影像组学热潮不减,在医学影像发展中依然占据主要地位.肺结节相关、胸部磁共振成像、双能CT成像、慢性肺阻塞性疾病和间质性肺病以及新颖的成像新技术(光子计数检测器、暗场X射线)同样值得关注.本文针对上述内容进行较全面的综述.

RSNA 2019年会的主题是“携手预见未来”,强调对临床和影像信息的整合,对患者全方位的关爱.深度学习依旧扮演着重要角色,在病灶检测、图像重建等领域应用越来越广泛.能谱CT技术、低剂量扫描技术愈加成熟.影像组学等技术在临床应用中的探索越来越多.急诊CT对扫描时间和对比剂等的要求更高.肺部MRI在功能评估中的应用越来越多.技术的落脚点始终是临床问题,即解决医生和患者的需求.

目的:利用磁共振扩散加权成像(DWI)评估肺癌术前纵隔淋巴结的转移情况,探讨其在鉴别转移性和非转移性纵隔淋巴结中的临床价值.方法:对30例肺癌患者行肺部MRI常规和DWI检查.DWI采用单次激发自旋回波-平面回波(SSEPI)和短反转时间恢复序列(STIR)序列.将DWI图像中纵隔淋巴结和术中切除淋巴结进行严格匹配,利用感兴趣区法分别测量原发灶和各纵隔淋巴结的表观扩散系数(ADC)值为ADC原发灶和ADC淋巴结,并计算得到ADC原发灶和ADC淋巴结的差值绝对值D-value,比较转移组淋巴结和非转移组淋巴结的ADC值和D-value值有无统计学差异.结果:转移组淋巴结的ADC值为(2.04±0.53)×10-3 mm2/s,非转移组淋巴结ADC值为(2.98±0.48)×101 mm2/s,转移组淋巴结ADC值明显低于非转移组淋巴结(P＜0.001).转移组淋巴结的D-value值为(0.76±0.45)×10-3 mm2/s,非转移组淋巴结的D-value值为(1.58±0.46)×10-3mm2/s,转移组淋巴结的D-value值明显低于非转移组淋巴结(P＜0.001).ADC值取0.0025×10-3mm2/s为临界值鉴别转移和非转移性淋巴结的敏感度、特异度、阳性预测值、阴性预测值分别为87.3％、84.6％、82.7％、88.7％;D-value值取0.001×10-3mm2/s为临界值鉴别转移和非转移性淋巴结的敏感度、特异度、阳性预测值、阴性预测值分别为76.4％、87.7％、84.0％、81.4％.结论:DWI通过测量、计算纵隔淋巴结的ADC值和D-value值,可用于肺癌患者术前评估淋巴结转移情况.

AbstractObjective: This study is to assess the value of hemodynamic parameters of DCE-MR imaging in differentiating solitary pulmonary nodules(SPNs).Materials and Methods:A total of 62 patients (42 malignant nodules, 13 benign nodules and 7 active infections) with SPNs underwent DCE-MRI exams before bolus injection and after 15 phases since bolus injection of Gd-BOPTA , at the rate of 30 seconds. From the temporal-signal curves, the following analysis were taken: signal enhancement ratios at 1, 2, 4 minutes after bolus injection(SI1%、SI2%、SI4%)and the maximum enhancement ratio( MER ); time at the maximum enhancement ratio (Tmax ); the steepest slope of time-signal curves (SS) and washout ratio.Results:It was found that SI1%、SI2%、SI4%、MER、SS for the malignant SPN group were significantly higher than those for the benign SPN group and significantly lower than those for the active infection group(P<0.05). With 2.23 and 0.63 as the threshold maximum enhancement ratio for distinguishing malignant nodules from benign nodules and active infection, the sensitivity, nagative predictive value, accuracy is 100%、100%、92%, respectively. Diagnostic accuracy is further improved combined with morphologic features of nodules.Conclusions:The hemodynamic parameters and morphologic characteristics of DCE-MRI may be a useful tool in differentiating malignant SPN from active infection SPN, as well as benign SPN.

Objective:This study is to investigate if kinetic parameters of DCE-MR imaging may help to differentiate ma-lignant and benign SPNs.Methods:A total of 47 patients with SPNs (31 malignant nodules and 16 benign nodules)under-went routine SE/T1WI and FSE/T2WI scanning and liver acquisition of volume accelaration (LAVA)DCE-MRI exams. Two experienced radiologists measured the signal intensity of the mass in 15 phases,generating temporal signal curves.The following analysis were taken:signal at 1,2,4 minutes after bolus injection and the maximum enhancement ratio (MER);time at the maximum enhancement ratio (Tmax);the steepest rising slope of time-signal curves;mean enhancement value and washout ratio.Results:It was found that ME,SI1%,SI2%,SI4%,MER,SS,Tmax for the malignant group were signif-icantly different from those for the benign SPN group (P <0.05)and SI1%,SI2%,SI4%,MER,Tmax,SS were much sig-nificantly different (P <0.01).The temporal-signal curves were classified into four types.The results showed that type A and B curves were main types for malignant nodules,whereas type B and C mainly occur in the case of benign nodules.In type D three were all benign tumors.Conclusion:DCE-MRI may be a viable tool in differentiating malignant SPNs from be-nign SPNs with the use of kinetic parameters.

2012年的RSNA胸部研究热点主要集中在COPD肺功能的影像学评估、肺肿瘤的诊断和鉴别诊断、胸部低剂量CT扫描技术及肺栓塞的影像诊断,重点是肺特殊气体应用、PET-CT与MRI-PT的对比研究及肺能谱CT的应用等.

病例资料 患者,女,26岁,剖宫产术后9月,发现大量腹水6月,再发加重半月入院,既往无心脏病、高血压病史.查体:营养不良,腹部膨隆,肝颈静脉回流征阳性,双下肢轻度水肿.心电图:交界性自主心律,频发室早,低电压,高侧壁、前间壁缺血样ST-T改变.彩超示:全心扩大并收缩功能减低(以右心扩大为主),淤血肝,腹腔积液,双侧胸腔积液.氨基末端脑钠肽前体:11641 pg/ml.心脏MRI示:左、右心室扩大伴心功能不全,心包积液、胸腔积液(图1～2)、腹腔积液,考虑围产期心肌病.

2012年的RSNA心血管影像热点与往年基本一致,对心衰患者的心功能评价,冠脉、心肌病、心瓣膜病变、先天性心脏病、左房和肺静脉病变、糖尿病及对比剂方面的影像研究病变等均有不少报道。CT方面的研究采用二代双源CT及双能量扫描模式对心血管疾病诊断以及在达到准确诊断的同时如何降低辐射剂量。MRI新技术主要为应用4D-VEC对大血管病变及胎儿心脏进行诊断,取得较好的结果。

Objective:To investigate the feasibility of myocardial magnetic resonance multi-b values diffusion-weighted imaging.Methods:Eleven healthy volunteers underwent myocardial multi-b values diffusion-weighted imaging.Image quality was evaluated by two radiologists independently.ADCslow,ADCfast and fraction of ADCfast were measured in anterior and posterior ventricular septal and free wall on the standard axis and cardiac short axis images.The agreement of two radiologists was evaluated by Bland-Altman plot and Pearson correlation analysis.Results:8 volunteers(73%) obtained images of Class I(6/16,37.5%)or Class II(10/16,62.5%) on standard axis and cardiac short axis images.According to the Bland-Altman plot and Pearson correlation analysis,ADCslow value [(0.0027±0.0009)×10-3~(0.0051±0.0029)×10-3mm2/s],ADCfast value [(0.1478±0.0832)×10-3~(0.1935±0.0817)×10-3mm2/s] and fraction of ADCfast[(0.1377±0.1380)~(0.2957±0.1166)] measurement had a good inter-observer agreement [95% limits of agreement(-1.5599,1.4510),correlation coefficient r=0.814].Conclusion:With breathe training,heart rate control and appropriate scanning parameters application,it is feasible to obtain myocardial multi-b values diffusion-weighted images,and have a good inter-observer agreement of the measurements.

<正>RSNA2011在乳腺方面的论文比去年有显著增加,论文质量也有明显的提高,更注重多中心和大样本研究,尤其突出MRI常规技术在诊断和鉴别诊断方面的应用,功能性MRI技术的临床应用也不少,笔者简要概括一下本次大会的主要内容。乳腺MRI