Multislice Spiral Computed Tomography of the Heart: Technique, Current Applications, and Perspective

Multislice spiral computed tomography (MSCT) is a rapidly evolving, noninvasive technique for cardiac imaging. Knowledge of the principle of electrocardiogram–gated MSCT and its limitations in clinical routine are needed to optimize image quality. Therefore, the basic technical principle including essentials of image postprocessing is described. Cardiac MSCT imaging was initially focused on coronary calcium scoring, MSCT coronary angiography, and analysis of left ventricular function. Recent studies also evaluated the ability of cardiac MSCT to visualize myocardial infarction and assess valvular morphology. In combination with experimental approaches toward the assessment of aortic valve function and myocardial viability, cardiac MSCT holds the potential for a comprehensive examination of the heart using one single examination technique.     

孤立性锁骨下动脉的MSCT诊断

目的 探讨孤立性锁骨下动脉的MSCT诊断与临床价值.方法 对8例孤立性锁骨下动脉的MSCT检查结果进行回顾性分析.结果 8例均显示一侧锁骨下动脉与主动脉弓无连接,而由同侧的椎动脉供血,其中5例还通过管型动脉导管与同侧肺动脉近端或主肺动脉远端相连.结论 孤立性锁骨下动脉能通过MSCT诊断得出正确的结论并对临床治疗有指导性意义.     

Role of Spiral and Multislice Computed Tomography in the evaluation of traumatic and spontaneous oesophageal perforation. Our experience

PURPOSE: To assess the role CT in the evaluation of traumatic and spontaneous oesophageal perforation. MATERIALS AND METHODS: From March 2001 to May 2003, we studied 12 patients (7 males and 5 females; age range: 25-66 years, mean age: 43.5 years) with suspected oesophageal perforation due to motor-vehicle accidents (4 cases), stab wound (one case), post-intubation (2 cases), foreign body ingestion (2 cases) and spontaneous (3 cases). Five patients underwent standard chest and cervical radiography; two patients with suspected foreign body ingestion also underwent a gastrografin swallow study; all of the 12 patients underwent CT of the neck, chest and abdomen before and after intravenous, and in four cases oral, administration of contrast material. RESULTS: In 5 patients with cervical, thoracic and abdominal trauma, the CT examination showed the presence of pleuroparenchymal injury (pneumothorax, pleural effusion and subcutaneous emphysema) as well as findings suggestive of oesophageal perforation: peri-oesophageal air (5 cases), peri-oesophageal fluid (4 cases), oesophageal wall thickening (3 cases), oesophageal wall laceration (2 cases) with abnormal course of the nasogastric tube in one of them and extraluminal extravasation of oral contrast material (2 cases). In 2 patients with post-intubation complications, CT showed the presence of a small peri-oesophageal fluid collection containing small gas bubbles in one case, and a gross perioesophageal abscess-like collection in the second case. In the 2 patients with foreign body ingestion, the plain radiography associated with CT showed the presence of a thin metal object in the cervical region (fragment of a dental plate) and a small extraluminal extravasation of gastrografin in one case, whereas in the other case CT showed the presence of a foreign body (chicken bone) in the hypopharynx with oesophageal wall thickening and peri-oesophageal oedema. In the remaining three patients with suspected spontaneous oesophageal perforation, CT showed the presence of a intramural haematoma in one case, oesophageal fluid distension with gas and a small peri-oesophageal fluid effusion (Mallory-Weiss syndrome) in another, and oesophageal rupture (Boerhaave syndrome) in the last case. CONCLUSIONS: Our experience shows that in patients with suspected traumatic and spontaneous oesophageal perforation, standard cervical and chest radiography may suggest a suspected oesophageal perforation in only a small proportion of cases, whereas oral contrast oesophagography has a higher sensitivity. Through the careful analysis of suggestive and specific signs of oesophageal perforation, a correct CT examination enables an accurate and timely diagnosis which significantly affects prognosis and provides valuable indications for treatment.     

多层螺旋CT冠状动脉成像的临床应用探讨

目的：探讨多层螺旋CT冠状动脉成像技术的应用和临床价值。材料和方法：对32例（包括3例冠状动脉搭桥术后和1例冠状动脉成形术及支架置入术后病人）进行了MSCT冠状动脉成像检查，并进行CT图像重建后处理，重建出各主要血管，对冠状动脉搭桥术后的病人重建出桥血管及含支架血管。分析MSCT对冠状动脉的显示能力，并分析是否有管壁钙化和软性斑块，评价管腔狭窄及其程度。对桥血管和支架的显示及通畅性进行评价。结果：MSCT冠状动脉成像对冠状动脉近中段显示清晰，显示率达90％以上；对冠状动脉钙化和软性斑块显示良好，对冠状动脉狭窄显示较佳。7根搭桥血管其中有1根可见约75％-90％的狭窄，其余均通畅，支架显示良好。结论：MSCT冠状动脉成像可作为冠状动脉粥样硬化疾患筛选手段，对血管搭桥术和支架放置并进行术后评价有很高的价值。     

多层螺旋CT扫描正常内耳容积再现技术成像参数研究

目的:探讨多层螺旋CT容积再现技术(VRT)正常内耳成像的最佳成像参数。方法:对10例(20耳)健康志愿者进行MSCT扫描,并对双侧耳分别进行重叠放大重建,重建间隔分别采用0.1mm(重叠86.7%)、0.2mm(重叠73.3%)、0.3mm(重叠60%)、0.4mm(重叠46.7%)和0.5mm(重叠33.3%),然后以容积再现技术(VRT)对内耳进行图像重组,比较不同重建间隔对VRT图像质量的影响。调整VR重组的阈值,分别选择-1000～0HU、0～ 1000HU和-1000～ 1000HU,比较3组阈值对图像质量的影响。结果:三组阈值间VRT图像质量有明显差异,其中以-1000～ 1000HU为最佳,其图像内耳结构显示完整、清晰,边缘清晰锐利,立体感较强,无明显伪影;以阈值-1000～0HU所得图像最差,内耳结构显示粗细不均、密度不等,半规管显示不完整。重建间隔为0.1和0.2mm时图像立体感较强,分辨力较高,内耳结构显示清晰。结论:MSCT内耳成像0.75mm准直器宽度时选择0.2mm重建间隔所得VRT图像质量最佳;VR图像重组时阈值-1000～ 1000HU时内耳三维结构显示最佳。     

BMI指数及自动管电流调节技术降低螺旋CT腰椎扫描辐射剂量的价值

目的:探讨身体质量指数(BMI)与自动管电流调节技术(ATCM)联合应用在腰椎容积螺旋CT扫描降低辐射剂量中的价值。方法:前瞻性设计和连续收集我院进行腰椎螺旋CT检查50例,根据BMI指数分A大组(BMI≤24kg/m~2)和B大组(BMI>24kg/m~2),各25人,两组内随机分为5个亚组,分别接受以下5组不同扫描参数组合进行容积CT扫描:亚组1采用固定管电流技术,405mAs,120kV;亚组2～5均采用自动管电流调节技术,噪声值分别为21Hu、25Hu、25Hu、25Hu,管电流范围分别为100～710mAs、100～710mAs、40～300 mAs、40～300 mAs,管电压分别为120kV、120kV、120kV、100kV。记录随机容积CT剂量指数(CTDIv01)及剂量长度乘积(DLP)。对图像进行质量评分,并测量各组腰4～5椎间盘中心水平两侧腰大肌标准差(SD)及信噪比(SNR),进行统计学分析。结果:A和B两大组的组内5小组间BMI值均相似(P<0.001)。A大组1～5亚组CTDIvol值、DLP值存在统计学差异(P<0.001),第5组CTDIvol值、DLP值分别为第1组的37.46%、38.59%;主观图像质量评分在5个亚组间无统计学差异;腰大肌SD值在各亚组间存在统计学差异,信噪比在各亚组无统计学差异。B大组内1～5小组CTDI vol值、DLP值存在统计学差异(P<0.01),第4组、第5组CTDIvol值分别为第1组的67.11%、42.60%,DLP值分别为第1组的65.07%、40.93%;主观图像质量评分、腰大肌SD值、信噪比存在统计学差异。结论:BMI指数的应用有助于更好地利用自动管电流调节技术降低辐射剂量,而不引起的图像质量的降低。BMI≤24kg/m~2受试者可采用亚组5参数进行扫描,BMI>24kg/m~2受检者应采用亚组4参数进行扫描。