64层螺旋CT胸部低剂量扫描方案优选的多中心研究

目的 比较自动曝光控制技术(AEC)与管电流恒定技术(CCC)2种不同低剂量MSCT扫描方案对胸部CT图像质量的影响,探讨更加合理的肺低剂量扫描参数方案.方法 采用前瞻性多中心研究方法,研究对象为7所医院就诊的280例行胸部低剂量MSCT检查的受检者,设定管电流(mA)为研究变量,方法一为AEC技术,下设噪声标准差值(SD)为25(A1)及30(A2)各1组,并设定管电流上限为80 mA,下限为10 mA;方法二为CCC技术,下设40 mA(C1)及50 mA(C2)各1组;共4组,采用同一机型64层MSCT行胸部低剂量扪描.2名放射科医师应用双肓法阅片,比较2种不同扫描技术的曝光剂量、SD值,横断面、MPR的图像质量以及体质量指数(BMI)对图像质量的影响.曝光剂量及SD比较行方差分析及t检验;图像质量比较行Mann-Whitney检验;医师对图像诊断一致性检验行Kappa分析.结果 剂量长度乘积(DLP)AEC组较CCC组明显降低[(82.62±40.31)和(110.81±18.21)mGy·cm,F=56.88,P＜0.01].AEC技术中A2组DLP较A1组低[(72.77±36.68)和(92.46±41.61)mGy·cm],差异无统计学意义(t=0.82,P＞0.05).前者SD值在肺窗[(41.50±9.58)和(40.86±7.03)HU]及纵隔窗[(41.19±7.83)和(40.92±9.89)HU]均略高于后者,差异无统计学意义(F肺窗=0.835、1.910,P值均＞0.05).横断面图像质量AEC组肺窗得分除右下肺静脉水平[(4.92±0.25)和(4.93±0.17)分]、[左膈顶上缘水平(4.91±0.27)和(4.93±0.22)分]较CCC组略低外,AEC组得分均较CCC组略高[头臂静脉上缘(4.49±0.56)和(4.38±0.64)分;主动脉弓上缘(4.86±0.23)和(4.81±0.32)分;右肺上叶支气管开口(4.87±0.27)和(4.84±0.22)分;右肺中叶支气管开口(4.90±0.25)和(4.88±0.21)分],差异无统计学意义(F=0.076～1.748,P值均＞0.05);纵隔窗得分除头臂静脉上缘水平AEC组较CCC组高[(2.57±0.77)和(2.46±0.59)分],且差异有统计学意义(F=8.459,P=0.047)外,余各层面AEC组得分均较CCC组略低[(主动脉弓上缘(3.36±0.63)和(3.45±0.60)分;右肺上叶支气管开口(3.94±0.56)和(3.95±0.51)分;右肺中叶支气管开口(3.80±0.58)和(3.87±0.50)分;右下肺静脉(3.72±0.56)和(3.78±0.53)分;左膈顶上方(3.58±0.63)和(3.68 ±0.56)分],但差异均无统计学意义(F=0.083～3.380,P值均＞0.05).MPR图像质量肺窗及纵隔窗观察均略好于CCC组(Z肺窗=-2.358,Z纵隔窗=-1.330,P值均＞0.05).偏瘦、正常或偏重人群组,A1组肺窗及纵隔窗图像质量均优于A2组,差异无统计学意义(偏瘦:Z肺窗=0.000、Z纵隔窗=0.000;正常:Z肺窗=-0.062、Z纵隔窗=-0.746;偏重:Z肺窗=-1.177、Z纵隔窗=-1.715;P值均＞0.05),但在偏重人群纵隔窗图像质量A1组更好于A2组(Z=-1.715,P=0.144).结论 AEC组总曝光剂量明显低于CCC组,而AEC组的图像质量及SD值无论在肺窗或纵隔窗均与CCC组无明显差异,故建议在胸部低剂量筛查方案选择中应用AEC技术,对偏胖者宜采用SD=25方案,对正常及偏瘦者宜采用SD=30方案.

Abstract：

Objective To compare the image quality of chest low dose CT (LDCT) using automatic exposure control (AEC) and constant current control (CCC) and explore a more reasonable scanning protocol. Methods Two hundred and eighty participants were examined with 64 CT scanner at 7 centers in China. All were divided into 4 groups. Two groups underwent LDCT using AEC with standard deviation set at 25 (A1) and 30 (A2) respectively and the tube current ranged from 10 mA to 80 mA. The other two groups underwent LDCT using CCC with tube current set at 40 mA (C1) and 50 mA (C2) respectively. The axial and MPR images were evaluated by two radiologists who were blinded to the scanning protocols.The radiation dose, noise and the image quality of the 4 groups were compared and analyzed statistically.Differences of radiation dose and noise among groups were determined with variance analysis and t test,image quality with Mann-Whitney test and the consistency of diagnosis with Kappa test. Results There was a significant lower DLP in AEC group than in CCC group [(82.62±40.31)vs ( 110.81±18.21) mGy·cm (F =56. 88 ,P ＜ 0. 01 )], whereas no significant difference was observed between group A2 and group A1 0. 05]. The noisy of AEC group was higher than that of CCC group both on lung window(41.50±9.58 vs 40.86±7.03) and mediastinum window (41.19±7.83 vs 40.92±9.89), but there was no significant difference( Flung =0.835, P=0.476, Fmediastinum =1.910, P=0.128).The quality score of axial image in AEC group was higher than that in CCC group (superior margin of the brachiocephalic vein level: 4.49±0.56 vs4.38±0.64,superior margin of the aortic arch: 4.86±0.23 vs 4.81±0.32,the right superior lobar bronchus Level:4.87±0.27 vs 4. 84 ± 0. 22, the right middle lobar bronchus Level: 4.90±0.25 vs 4.88±0.21) except on the right inferior pulmonary vein level(4. 92 ±0. 25 vs 4. 93 ±0. 17) and superior margin of the left diaphragmatic dome level (4. 91±0.27 vs 4.93±0.22) on lung window, but no significant differences (F=0.076-1.748, P＞0.05) were observed. A significant higher score in AEC group was observed on mediastinum window compared with CCC group on superior margin of brachiocephalic vein level (2.57±0.77 vs 2. 46 ± 0. 59, F = 8. 459, P ＜ 0. 05 ), however, the score of AEC group was lower than that of CCC group on other levels without significant differences (superior margin of the aortic arch:3.36 ±0. 63 vs 3.45 ±0. 60,the right superior lobar bronchus level: 3.94 ±0. 56 vs 3. 95 ±0. 51 ,the right middle lobar bronchus Level: 3.80 ±0. 58 vs 3. 87 ±0. 50,the right inferior pulmonary vein level: 3.72 ±0. 56 vs 3.78 ±0. 53, superior margin of the left diaphragmatic dome level: 3.58 ± 0.63 vs 3.68±0.56,F=0.083-3.380,P ＞ 0.05 ). The MPR image quality of AEC group was better than that of CCC group both on lung window and mediastinum window (Zlung =-2.258, Zmedlastinum=-1.330, P＞0.05). For all participants including the underweighted group, the normal group and the overweighted group, the image quality of A1 group was better than that of A2 group without significant differences (the underweighted group: Zlung=0.000, P=1.000, Zmedastinum= 0.000, P=1.000;the normal group: Zlung =-0.062, P=0.950, Zmediastinum =-0.746, P = 0.456; the overweighted group: Zlung = - 1.177, P = 0.239,Zmediastinum =-1.715, P=0.144) both on lung and mediastinum windows, and for the higher BMI participants, a better image quality was obtained in A1 group than in A2 group on the mediastinum window (Z = -1. 715, P = 0. 144). Conclusions The total radiation exposure dose of AEC group is significantly lower than that of CCC group, but no statistical significant differences are observed between both groups in image quality and noise level. The AEC technique is highly recommended in thoracic LDCT scan for screening program, and the SD25 ( SD value = 25) scan protocol is suggested for higher BMI population while the SD30 (SD value = 30) scan protocol for lower BMI population.     

胸部节细胞神经瘤的CT和MRI表现

目的 探讨胸部节细胞神经瘤的CT及MRI表现,提高对该病的诊断和鉴别诊断能力.方法 回顾性分析20例经手术病理证实的胸部节细胞神经瘤的临床、CT(14例)、MR(6例)平扫和增强扫描及所有病理学资料.结果 20例胸部节细胞神经瘤中,发生于后纵隔17例、侧胸膜2例、右侧整个胸腔1例.14例肿瘤平扫CT值20～40 HU,平均30.5 HU,4例伴有小结节状钙化,1例伴有斑片状脂肪密度影;动脉期增强CT值0～12 HU,平均6.2 HU,延迟期增强10～20 HU,平均14.3 HU.MRI检查5例在T1 WI上为均匀低信号,1例在T1WI上低信号内夹杂斑片状高信号脂肪影;T2WI上6例为不均匀高信号,其中1例呈旋涡状征象;增强后动脉期呈轻度不均匀强化,延迟期逐渐进行性轻度强化.结论 增强后CT及MRI显示肿瘤在动脉期不强化或轻微强化、延迟后逐渐轻度强化是胸部节细胞神经瘤的特征性表现.     

Evaluating the role of ultrasound in chest trauma: Common complications and computed tomography comparative evaluation

Objective

to establish the role of transthoracic ultrasound as a bed-side, available, and affordable technique for imaging chest trauma patients and compared its sensitivity, specificity and accuracy for detecting chest trauma sequelae and complications to those of CT.

Optimisation of transcutaneous cardiac pacing by three-dimensional finite element modelling of the human thorax

The goal of the study is to determine by finite element analysis (FE) the optimal electrode placement, size and electrolyte resistivity that minimise the pain experienced by patients during successful transcutaneous cardiac pacing (TCP). The three-dimensional FE model generated for this purpose has 55 388 nodes, 50 913 hexahedral elements and simulated 16 different organs and tissues, as well as the properties of the electrolyte. The model uses a non-uniform mesh with an average spatial resolution of 0.8 cm in all three dimensions. To validate this model, the voltage across 3 cm² Ag−AgCl electrodes is measured when currents of 5 mA at 50 kHz are injected into a subject's thorax through the same electrodes. For the same electrode placements and sizes and the same injected current, the FE analysis produced results in good agreement with the experimental data. The optimisation analysis tested seven different electrode placements, five different electrode sizes and six different electrolyte resistivities. The analysis indicates that the anteriorposterior electrode placement, electrode sizes of about 90 cm² and electrolytes with resistivity of about 800 ω·cm yield the most uniform current distribution through the skin, thus having the best chances to minimise the pain delivered to the patient during successful TCP. The anterior-anterior electrode placement is the second most efficient.     

Ten‐year analyses of the German DRG data about negative pressure wound therapy

Exact data regarding the clinical role of negative pressure wound therapy (NPWT) for wound care in a specific country are not available. Thus, we analysed the use of NPWT in hospitalised patients in Germany. Detailed lists of all hospitalised cases treated with NPWT in Germany for each of the years from 2005 to 2014 were obtained from the Federal Statistical Office, as well as lists of the 15 most frequent principal and additional diagnoses documented with NPWT in 2014. Within the 10‐year time period of the study, the number of cases treated with NPWT increased by 349%, from 37 053 in 2005 to 129 269 in 2014. The rate of all hospitalised cases treated with NPWT increased form 0·22% to 0·66% in Germany. In 2014, wounds affecting skin and subcutaneous tissue (5–916.a0) are the most frequent documented indication for NPWT followed by deep wounds involving bones and joints at the limbs (5–916.a1). Open abdomens (5–916.a3) count for higher numbers than deep wounds of the thorax, mediastinum and sternum (5–916.a2). Fifty percent of all cases hospitalised for stage IV pressure ulcers at sacrum or ischium and around one third (32.2%) of cases with pyothorax received NPWT. Every fourth to fifth case hospitalised for disruption of surgical wounds or infections following a procedure (24·1%), as well as for infections and inflammations because of internal joint prosthesis or because of an internal fixation device was treated with NPWT (22·9%). In cases with diabetic foot syndrome, it is still every tenth case (10·1%). This analysis shows a substantial increase in the use of NPWT in the last decade for hospitalised patients. NPWT has a fixed role in the treatment of stage IV pressure ulcers at sacrum or ischium, pyothorax, infection and inflammation because of internal joint prosthesis or an internal fixation device and diabetic foot syndrome.     

CT diagnosis of cardiac and pericardial injuries

The purpose of this retrospective study was to determine the CT findings diagnostic of cardiac and pericardial injury, including signs of pericardial tamponade, in patients suffering from blunt and penetrating trauma. A search of the CT radiology database at a level I trauma center was performed to identify cases in which injury to the heart or pericardium was diagnosed, as well as to identify cases of pericardial tamponade. All cases were reviewed to ascertain the specific CT findings, and medical records were reviewed to assess the influence of CT findings on management and to assess for clinical evidence of pericardial tamponade. Eighteen patients had direct CT evidence of cardiac or pericardial injury, including nine cases of pneumopericardium, eight cases of hemopericardium, and one case of intrapericardial gastric herniation. Four of these patients were found to have direct cardiac injuries. Three additional cases with CT evidence of pericardial tamponade were identified, two secondary to cardiac compression by an anterior mediastinal hematoma and one following repair of left ventricular rupture. Of 11 patients with CT evidence of tamponade, only three were suspected clinically. Cardiac and pericardial injuries are usually diagnosed surgically and are often clinically unsuspected, particularly in blunt trauma. As CT is increasingly utilized as a general screening test for thoracic/abdominal trauma, these injuries may be first suspected on the basis of CT findings, and knowledge of the CT findings of cardiac injury or tamponade is crucial.     

高能战斗部致绵羊胸部伤的实验研究

目的　研究高能战斗部 (HEF)致胸部伤特点和规律 ,为胸部爆炸伤的救治提供原则和依据。　方法　用电启动的方式引爆HEF ,将 45只绵羊布放于距爆心 30～ 2 40m处 ,致伤时测量冲击波超压和破片速度 ,致伤后进行病理解剖观察。　结果　胸部破片伤的发生率为 6 7% (30 /45 ) ,伤后即刻死亡率为 73% ;损伤类型以盲管伤和贯通伤为主 ,分别为 5 7%和 31% ;在 30只有胸部破片伤的动物中 ,肺冲击伤、肋骨骨折、大量胸腔积血 (>10 0 0ml)及胸腹联合伤的发生率分别为80 %、33%、2 7%和 33% ,心脏被直接击中的概率为 33 %。　结论　破片击中胸部的概率高 ,胸壁穿透伤多 ,伤情严重 ,伤后多迅速死亡。胸部严重毁损、心脏破片伤、多脏器受损以及快速失血是其主要死亡原因。     

胸部CT低剂量扫描的图像质量与吸收剂量关系分析

目的　探索多层螺旋CT在胸部低剂量扫描的可能性和合理性。方法　 (1)X线吸收剂量测试 :用 12 0kV、0 75s、分别测试 8与 3mm层厚的 115 0、4 0 0、2 5 0、7 5mAsX线照射剂量。计算吸收剂量指数 ,并加以比较。 (2 )水体模测试CT值的均匀性和噪声水平 :在水体模的同一层面 ,用 12 0kV、 0 75s分别作 8与 3mm层厚的 115 0、4 0 0、2 5 0、7 5mAs扫描。在每幅图像的相同位置测 5个兴趣区 ,作CT值的均匀性和噪声水平比较。 (3)病例CT扫描 :随机选择肺部块影和片状影的患者各 30例。用 12 0kV ,0 75s,8与 3mm层厚在同一层面作 115 0、4 0 0、2 5 0、15 0、7 5mAs扫描。另选 15例作 190、15 0、4 0、2 5、15mAs螺旋扫描。作不同厚度的重建间隔对比和后处理图像最大密度投影 (MIP)、计算机容积摄影 (CVR)、多平面重建 (MPR)、高分辨率CT(HRCT)、三维成像(3D)、仿真支气管镜等效果比较。 (4)图像质量评估 :由 4名CT医生盲法评价CT图像。按正常图像、图像有少许伪影、图像有严重伪影的等级评判每一幅图像 ,进行统计学处理。结果　 (1)X线吸收剂量指数测试表明 ,115 0mAs的X线吸收剂量指数大于 4 0 0、2 5 0、7 5mAs的指数分别在 6 0 %、70 %、85 %以上。 (2 )水模测试结果 ,CT图像的均匀性随CT扫     

白血病的胸腹部CT表现及其临床价值

目的 :探讨白血病患者的胸腹部CT征象及其病理基础、临床联系。方法 :本组 116例白血病患者 ,男 71例 ,女 45例 ,急性淋巴细胞性白血病 3 0例 ,急性非淋巴细胞性白血病 61例 ,慢性淋巴细胞性白血病 7例 ,慢性粒细胞性白血病 18例。每例均作CT平扫和增强扫描。结果 :急性淋巴细胞性白血病以深部淋巴结浸润为主 2 5 /3 0例 ( 83 %)、急性非淋巴细胞性髓外浸润肺部最多见 3 5 /61例 ( 5 7%)、慢性淋巴细胞白血病以浅表淋巴结浸润为主 6/7例 ( 86%)、慢性粒细胞性白血病以中重度脾大 18/18例 ( 10 0 %)伴浸润 6/18例 ( 3 3 .3 %)显著。结论 :胸腹部CT征象对白血病的诊断、治疗有参考价值。     

严重肺挫伤的临床诊治体会

目的：总结严重肺挫伤的诊治特点。方法：回顾分析2003年2月—2010年12月收治的198例严重肺挫伤[损伤严重度评分（ISS）≥20分]患者的临床资料。结果：198例患者中治愈165例,治愈率为83.3%;病死33例,病死率为16.7%。结论：胸部影像学检查是诊断严重肺挫伤的可靠依据,保持呼吸道通畅、抗休克、积极治疗合并伤、合理应用机械通气、激素和抗生素是其治疗的重要方法,早期诊断并及时处理合并伤是提高抢救成功率的关键。