Comparison of retrospectively ECG-gated and nongated MDCT of the chest in an emergency setting regarding workflow, image quality, and diagnostic certainty

Purpose This study aims to assess the influence of ECG-gated acquisition on workflow and to compare image quality and diagnostic certainty for retrospectively ECG-gated and nongated multidetector computed tomography of the chest in the emergency suite. Materials and methods Thirty-two consecutive patients were referred for both an ECG-gated and a nongated CT to rule out traumatic thoracic injury (n=15) or acute aortic dissection (n=17). The time from the start of the transportation from the emergency suite to the CT room until the start of the CT scan was recorded. Using a scoring system, the image quality of axial images and multiplanar reformats, the presence of disease, and the subjective diagnostic certainty were assessed with regard to the vascular structures, the bone structures, and the lung parenchyma. Results The time needed for transportation and patient preparation was 12.1±1.7 min (8.1–14.5 min). The motion artifacts of the thoracic aorta and the supra-aortic vessels were significantly reduced in the ECG-gated data acquisition compared with the nongated technique (P<0.001). Subjective diagnostic certainty for assessment of the aorta was significantly better using ECG gating. The image quality of the lung parenchyma (P<0.005), the spine (P<0.005), and the ribs (P<0.002) was inferior in the ECG-gated data sets but did not compromise the detection rate of traumatic lesions and fractures. Conclusion Performing ECG gating in the emergency room did not slow down the diagnostic workup. ECG-gated acquisition performed better in the assessment of the aorta, but image quality for lung and bone structures was slightly reduced. Further studies are required to assess the influence of the imaging technique on the diagnostic outcome.     

Unenhanced dynamic mediastinal computed tomography in the selection of patients requiring thoracic aortography for the detection of acute traumatic aortic injury

In our institution, the selection of patients who require thoracic aortography to evaluate for acute traumatic aortic injury (ATAI) is based upon an appropriate mechanism of injury and radiologic demonstration of a mediastinal hematoma. When plain chest or chest and/or mediastinal radiographs demonstrate a mediastinal hematoma, the patient undergoes thoracic aortography as promptly as is clinically feasible. If the plain film studies are negative for mediastinal hematoma, thoracic aortography is not performed because the patient is presumed not to have an ATAI. When the plain film studies are equivocal and the patient is stable, unenhanced computed tomography (CT) of the mediastinum is used to evaluate for a mediastinal hematoma. CT signs of a mediastinal hematoma include a soft tissue density, representing the hematoma admixed with mediastinal fat, which obscures or obliterates the normal aortic-mediastinal fat interface; hematoma admixed with fat of the right paratracheal stripe causing increased width and density of the stripe; and hematoma surrounding, and frequently displacing, the esophagus to the right of its normal position. Six of 36 patients (17%) with mediastinal hematoma demonstrated by unenhanced mediastinal CT had ATAI by thoracic aortography and confirmed surgically. The thoracic aortograms of the remaining 30 of 36 patients (83%) were negative. Sixty-three of 100 patients (63%) with equivocal plain chest or mediastinal radiographs had negative mediastinum by unenhanced CT. All 63 patients (100%) with normal mediastinal CT and who did not have thoracic aortography were discharged from the hospital 1–42 days (mean, 9.3 days) post-injury without clinical or radiographic signs of aortic rupture. Supported in part by the John S. Dunn Research Foundation.     

MRI和螺旋CT对主动脉夹层的对比研究及其临床应用

目的对比分析磁共振成像(MR I)和螺旋CT诊断主动脉夹层(AD)的影像特征,评价2种技术对临床的应用价值。方法回顾性分析经手术或临床证实的18例AD的MR I和螺旋CT表现。结果2种先进检查技术诊断AD的敏感性和特异性均较高,能不同程度地显示AD的范围及其分型、真假腔、内膜片和内膜破口、附壁血栓和壁内血肿、主动脉的扩张和狭窄及其分支血管受累情况。结论对疑有AD者应行MR I或螺旋CT检查,MR I与CT对病变范围及分型、真假腔及主动脉的狭窄和扩张的显示相似;而内膜片、内膜破口、附壁血栓和壁内血肿、主动脉整体及分支受累的显示MR I明显优于螺旋CT;对内膜及主动脉壁钙化、急危重者的检查螺旋CT优于MR I。     

Multi-detector computed tomography in the diagnosis and management of acute aortic syndromes

Acute aortic syndrome (AAS) is a spectrum of conditions, which may ultimately progress to potentially life-threatening aortic rupture. This syndrome encompasses aortic dissection (AD), intramural haematoma, penetrating atherosclerotic ulcer and unstable thoracic aortic aneurysms. Multi-detector CT (MDCT) is crucial for the diagnosis of AAS, especially in the emergency setting due to its speed, accuracy and ready availability. This review attends to the value of appropriate imaging protocols in obtaining good quality images that can permit a confident diagnosis of AAS. AD is the most commonly encountered AAS and also the one with maximum potential to cause catastrophic outcome if not diagnosed and managed promptly. Hence, this review briefly addresses certain relevant clinical perspectives on this condition. Differentiating the false from the true lumen in AD is often essential; a spectrum of CT findings, e.g., “beak sign”, aortic “cobwebs” that allows such differentiation have been described with explicit illustrations. The value of non enhanced CT scans, especially useful in the diagnosis of an intramural hematoma has also been illustrated. Overlap in the clinical and imaging features of the various conditions presenting as AAS is not unusual. However, on most instances MDCT enables the right diagnosis. On select occasions MRI or trans-esophageal echocardiography may be required as a problem solving tool.     

Can chest CT be used to exclude aortic injury?

PURPOSE: To determine whether chest computed tomography (CT) can be used to exclude aortic injury. MATERIALS AND METHODS: Patients in whom there was very high suspicion of traumatic aortic injury were examined with aortography only. Other patients were examined with contrast material-enhanced CT. Follow-up aortography was performed in all patients with moderate to high suspicion of traumatic aortic injury and in all patients with CT scans that were positive for traumatic aortic injury. CT scans were regarded as positive when they showed mediastinal hematoma or direct findings of aortic injury. During a 4 1/2-year period, 1,009 patients (263 female, 746 male; age range, 3-90 years) were evaluated for possible traumatic aortic injury. RESULTS: Of the 207 patients who underwent aortography directly without CT, 10 had traumatic aortic injury. Of the 802 patients who were examined with CT, 382 underwent follow-up aortography. In this group, there were 10 true-positive and no false-negative CT scans. CT had 100% sensitivity and a 100% negative predictive value for the detection of traumatic aortic injury.     

Evaluation of the role of chest computed tomography in the management of trauma patients

The role of chest computed tomography (CT) in the management of trauma patients is evolving. The present study reviews the chest radiographic and chest CT findings in a group of trauma patients to determine the clinical impact of findings noted exclusively on chest CT.Fifty-five trauma patients examined with chest radiography and chest CT and whose clinical charts were available for review were retrospectively identified. There were 46 men and 9 women, with a mean age of 39 years. The presence (and size) of pneumothorax, hemothorax, pulmonary contusion, and fractures was tabulated for the chest radiographs and CT scans. The presence of mediastinal widening on chest radiographs and all mediastinal findings on CT were noted. The results of aortography, when applicable, were correlated. The clinical charts were reviewed to assess the impact of CT findings on patient management.Pneumothorax (P<0.05), hemothorax (P<0.05), pulmonary contusions, and fractures were noted more frequently on chest CT than on chest radiography. However, clinical management was affected in only three (5%) of these patients. Chest CT findings related to the mediastinum affected patient management in 13 (24%) patients. CT obviated the need for aortography in 7 of 10 patients with mediastinal widening on chest radiographs. Six other patients had aortography, four for mediastinal hematoma with a normal-appearing aorta on contrast medium-enhanced CT, and two for mediastinal hematoma and aortic injury on CT.Despite detection of significantly more pneumothoraces and hemothoraces on chest CT, clinical management was affected in only a small minority (5%) of cases. CT did prove useful in evaluating the mediastinum, obviating the need for aortography in 7 of 10 patients with a widened mediastinum on chest radiography and accurately diagnosing the presence and site of aortic injury in the two patients with that diagnosis.     

CT and clinical features of hemorrhage extending along the pulmonary artery due to ruptured aortic dissection

The purpose was to evaluate CT findings of hemorrhage extending along the pulmonary artery (PA) due to ruptured aortic dissection (AD) and its prognostic factors. In 232 patients with Stanford type A AD, 21 patients (9.1%; 11 women; mean 70.3 years) were diagnosed. Twelve patients had double-barreled (classic) AD, and nine patients had intramural hematoma (IMH; closed false lumen) of the aorta. Based on CT findings, hemorrhage was classified into three categories as follows: category 1 (IMH of the PA or blood localized around the PA), category 2 (extending into the interlobular septa), and category 3 (extending into the alveoli). The factors influencing prognosis, including CT features and patient characteristics, were evaluated. Fourteen (66.7%) of the 21 patients underwent emergency surgery, and 8 (38.1%) patients died within 72 h of onset. Twelve cases (57.1%) were classified into category 1, 2 cases (9.5%) into category 2, and 7 cases (33.3%) into category 3. Double-barreled AD and category 3 hemorrhage were significant risk factors for death in univariate analyses. In multivariate analyses, the presence of category 3 hemorrhage was the only significant risk factor for death. CT findings indicative of a poor prognosis include double-barreled type AD and category 3 hemorrhage.     

Computed tomography in the diagnosis of traumatic rupture of the thoracic aorta

Over a 26-month period, 25 patients admitted to the Trauma Unit at UCSD Medical Center following blunt trauma were investigated for suspected traumatic rupture of the thoracic aorta by computed tomography (CT) of the chest. A retrospective review of these patients was performed. Twenty-one (84%) also had CT of other body areas, most commonly the head or abdomen. Nine of the 25 patients subsequently had aortography; in 15 patients the CT findings were felt at the time to exclude rupture, and one patient was not investigated further because of severe head injuries. In general, if CT failed to show a mediastinal haematoma, aortography was not performed. However, five patients with CT evidence of a haematoma, including two with vertebral fractures, were not investigated by aortography. Two of the 25 patients (8%) had angiographically proven aortic ruptures; in both CT had shown not only a haematoma but also an abnormal outline of the aorta on contrast-enhanced scans. The haematoma was large in one patient and small in the other. Although 10 of the 25 patients had unenhanced scans, no case of aortic rupture is known to have been missed. During the same study period, 47 patients were investigated for suspected aortic rupture solely by aortography. Four patients (8% of this group) had aortic rupture, and two had subclavian or innominate artery ruptures. Only a minority (approximately one-quarter) also had CT of the head or abdomen. The role of CT in the diagnosis of traumatic rupture of the aorta is critically assessed in the light of our experience and a review of the literature.     

CT断层图像和三维重建在主动脉腔内隔绝术术前评估中的价值

目的比较CT断层图像和三维重建在主动脉腔内隔绝术术前评估中的价值。方法将接受主动脉腔内隔绝术的20例主动脉夹层瘤和12例腹主动脉瘤患者作为研究对象,术前分别在CT断层图像与三维重建图像上测量的各相关参数,与主动脉造影所测量的相同参数进行对照分析。结果CT断层图像上所测量的主动脉弓直径及各种长度指标均小于主动脉造影结果;夹层瘤近段主动脉直径及近端瘤颈直径、主动脉中段直径以及左右髂动脉直径均大于主动脉造影结果;三维重建所测量的上述各项参数与主动脉造影结果非常接近,并能清楚显示夹层分离的破裂口,而断层图像上不易发现破裂口;断层图像和三维重建在显示主动脉附壁血栓和测量最大瘤体直径方面优于主动脉造影。以三维重建测量为标准选择覆膜支架,所有患者均成功封闭瘤体。结论主动脉腔内隔绝术术前评估时应结合CT断层图像和三维重建图像综合分析,覆膜支架的选择应以三维重建测量结果为主。     

Digital subtraction angiography in the preoperative evaluation of patients with a renal tumor

Inguinal intravenous digital subtraction angiography (DSA) was performed in 14 patients referred for preoperative evaluation of a renal tumor previously diagnosed by CT and ultrasound. Conventional cavography and aortography were used as reference methods for comparison. Both DSA and conventional angiography were carried out following selective arterial injection to the abnormal kidney. The diagnostic value of DSA in examination of the inferior vena cava was generally comparable to that of conventional cavography. Intravenous aortography was unsuccessful in 2 patients due to motion artifacts. In all other patients, the information provided by DSA regarding the aorta, renal arteries and renal veins was similar to that of conventional aortography. Intrarenal vascular detail, however, was far superior on conventional films and was only useful with DSA when intra-arterial injection was implemented. In one of the 12 diagnostic examinations, localization of the renal mass could not be established by intravenous DSA, but was possible in all others. The inguinal approach advocated permits simultaneous inferior vena cavography and intravenous aortography with one single injection of contrast medium; the method is less traumatic than aortography , and does not require hospitalization of the patient. DSA may also be of value in those cases still requiring selective catheterization of the renal arteries, i.e. for angiotherapy . Intra-arterial DSA then allows reduction of the amount of contrast medium and a rapid processing of the images without detriment to the quality of the examination.     

Role of contrast-enhanced helical CT in the evaluation of acute thoracic aortic injuries after blunt chest trauma

The purpose of this retrospective study was to determine the value of contrast-enhanced helical CT for detecting and managing acute thoracic aortic injury (ATAI). Between June 1995 and February 2000, 1419 consecutive chest CT examinations were performed in the setting of major blunt trauma. The following CT findings were considered indicative of ATAI: intimal flap; pseudoaneurysm; contour irregularity; lumen abnormality; and extravasation of contrast material. On the basis of these direct findings no further diagnostic investigations were performed. Isolated mediastinal hematoma on CT scans was considered an indirect sign of ATAI: In these cases, thoracic aortography was performed even if CT indicated normal aorta. Seventy-seven patients had abnormal CT scans: Among the 23 patients with direct CT signs, acute thoracic aortic injuries was confirmed at thoracotomy in 21. Two false-positive cases were observed. The 54 remaining patients had isolated mediastinal hematoma without aortic injuries at CT and corresponding negative angiograms. The 1342 patients with negative CT scans were included in the 8-month follow-up program and did not show any adverse sequela based on clinical and radiographic criteria. Contrast-enhanced helical CT has a critical role in the exclusion of thoracic aortic injuries in patient with major blunt chest trauma and prevents unnecessary thoracic aortography. Direct CT signs of ATAI do not require further diagnostic investigations to confirm the diagnosis: Isolated aortic bands or contour vessel abnormalities should be first considered as possible artifacts or related to non-traumatic etiologies especially when mediastinal hematoma is absent. In cases of isolated mediastinal hematoma other possible sources of bleeding should be considered before directing patients to thoracic aortography.     

Trauma of the chest

Trauma to the chest may cause a wide range of injuries including fractures of the thoracic skeleton, contusion or laceration of pulmonary parenchyma, damage to the tracheobronchial tree, diaphragmatic rupture or cardiac contusion. Conditions affecting primarily extrathoracic sites may have indirect effects on the lungs causing adult respiratory distress syndrome or fat embolism. Laceration of the aorta is the typical and likewise most life threatening complication of massive blunt chest trauma necessitating immediate diagnosis and repair.Conventional radiography rather than cross-sectional imaging is the mainstay in diagnosing thoracic trauma. During the critical phase with often concomitant shock, pelvic and spinal injuries tailored radiographic views or even upright chest radiographs are impractical. The severely traumatized patient is usually radiographed in the supine position and suboptimal roentgenograms may have to be accepted for several reasons. It is well documented that many abnormalities detected on CT were not apparent on conventional radiographs, but CT is reserved for hemodynamical stable patients. Nevertheless certain situations like aortic rupture require further evaluation by CT and aortography.The value of conventional radiography, CT, MRI and aortography in chest trauma is reviewed and typical radiographic findings are presented.     

The role of sonography in abdominal trauma: The European experience

Abdominal trauma may be a life-threatening entity. Whereas computed tomography (CT) seems to be the major noninvasive diagnostic tool for evaluation of abdominal trauma in the United States, sonography is the modality of first choice in the majority of European hospitals. Sonography has replaced diagnostic peritoneal lavage for detecting or excluding intraperitoneal free blood. We advocate sonography for any polytrauma patient in the trauma emergency room (TER), because it is a quickly performed, repeatable, and inexpensive imaging modality, serving as a decision-maker in the TER and enabling the avoidance of unnecessary CT. We strongly believe that radiologists should make full use of the potential of ultrasound in the TER. Radiologists should have access to, and experience with, CT as well as sonography, allowing an unbiased decision as to which modality is adequate to answer the specific questions raised by different trauma patients. This article defines the role of sonography in the TER and compares it with CT.     

外伤性主动脉夹层的CT诊断(附2例报告)

目的：探讨外伤性主动脉夹层的早期CT表现。方法：回顾性分析在我院漏诊及确诊的外伤性主动脉夹层的CT表现。2例中1例行3次CT平扫,1例行CT平扫和增强扫描。结果：2例均为DeBakeyIU型主动脉夹层,1例3次CT平扫示降主动脉管腔进行性增宽,伴双侧胸腔积液;此例因漏诊,患者于2周后死亡。另1例CT平扫示降主动脉增粗,CT增强扫描明确诊断,主要表现为降主动脉扩张,可见真腔、假腔及内膜线;此例患者行支架植入术后,患者预后良好。结论：对于胸部外伤患者,CT平扫时应注意观察主动脉的直径,如果降主动脉增粗、尤其是进行性增粗时,应考虑主动脉夹层的可能。     

Hepatic abscess caused by Brucella US,CT and MRI findings: case report and review of the literature

The authors describe the findings detected by ultrasonography (US), computed tomography (CT) and magnetic resonance imaging (MRI) in a 42-year-old patient with a hepatic abscess due to brucellosis. This localization by Brucella (hepatic brucelloma) is quite rare and very often is asymptomatic. A review of the medical literature shows only 40 cases of an hepatic abscess due to brucellosis. The findings demonstrated by US, CT and MRI can offer important diagnostic elements, albeit not specific, which should, together with a positive serologic test, confirm the diagnosis.     

Appropriateness of selection criteria for CT examinations performed at an emergency department

In the diagnosis of traumatic and nontraumatic emergencies, computed tomography (CT) is the most frequently performed procedure. The aims of this study were to find out whether CT report results can be used as a reliable tool for the diagnosis and management of patients at an emergency department and to evaluate the appropriateness of the selection criteria for CT examinations. For this reason, we analysed the emergency CT procedures according to the diagnostic hypothesis written on CT request forms, the results of the CT reports and the final diagnosis of the patients. One thousand consecutive CT procedures in the emergency department of a research hospital were retrospectively analysed. When the CT reports and the final diagnosis were evaluated, the sensitivity and specifity of the CT were found to be 0.81 and 0.85. According to the analysis of the CT reports, 55.8 % of all the patients were reported to be normal. When the patient files were examined for the final diagnosis of the patients, 55.7 % of the patients did not receive a final diagnosis related to the diagnostic hypothesis. The lowest correlation was found between the diagnostic hypothesis, the CT reports and the final diagnosis of the patients who underwent cranial CT procedure for trauma. The results of the CT reports can be used as a reliable parameter for the diagnosis and management of the patients at emergency departments. On the other hand, a high negative rate of CT reports was noted especially for the cranial CT examinations. CT selection criteria for the head trauma patients should be reconsidered. Since CT is a procedure involving ionising radiation, it is important that it is performed with the correct indications and the relevant clinical information is specified on the CT request forms.     

Penetrating trauma to the abdominal aorta: CT demonstration of active bleeding

Contrast-enhanced helical computed tomography (CT) is the imaging study of choice for evaluating the abdomen in hemodynamically stable patients following blunt trauma. Surviving victims of penetrating trauma, in contrast, are often hemodynamically unstable and may require urgent celiotomy with or without diagnostic peritoneal lavage (DPL) or ultrasonography. Abdominal CT is not routinely performed in this patient population, but may be done if the patient with penetrating abdominal trauma is stable on admission or becomes so with resuscitation. CT in this context can address questions regarding the location and extent of injury and help decide appropriate management. We present a case of a stabilized blunt and penetrating trauma patient with negative DPL and active retroperitoneal aortic extravasation demonstrated by CT. To our knowledge, penetrating injury to the aorta with active bleeding has not been previously seen on CT.     

Occult Mediastinal Great Vessel Trauma: The Value of Aortography Performed During Angiographic Screening for Blunt Cervical Vascular Trauma

Purpose To determine the value of aortography in the assessment of occult aortic and great vessel injuries when routinely performed during screening angiography for blunt cerebrovascular injury (BCVI).Methods One hundred and one consecutive patients who received both aortography and screening four-vessel angiography over 4 years were identified retrospectively. Angiograms for these patients were evaluated, and the incidence of occult mediastinal vascular injury was determined.Results Of the 101 patients, 6 (6%) had angiographically documented traumatic aortic injuries. Of these 6 patients, one injury (17%) was unsuspected prior to angiography. Four of the 6 (67%) also had BCVI. One additional patient also had an injury to a branch of the subclavian artery.Conclusion Routine aortography during screening angiography for BCVI is not warranted due to the low incidence (1%) of occult mediastinal arterial injury. However, in the setting of a BCVI screening study and no CT scan of the chest, aortography may be advantageous.     

MRI for acute chest pain: Current state of the Art

This article reviews the magnetic resonance imaging (MRI) and angiography (MRA) techniques, imaging findings, and evidence for evaluating patients with acute chest pain due to acute pulmonary embolus (PE), aortic dissection (AD), and myocardial infarction (MI). When computed tomographic angiography (CTA) is contraindicated, MRI and MRA are important alternative imaging modalities for diagnosis and management of patients with acute PE, AD, and MI. Familiarity with the techniques, imaging findings, and evidence is critical to safely and appropriately managing patients presenting with acute chest pain. J. Magn. Reson. Imaging 2013;37:1290–1300. © 2013 Wiley Periodicals, Inc.     

Hydatid disease of the soft tissues of the lower limb: findings in three cases

Three cases of hydatid disease are reported, all presenting as soft tissue lesions in the lower extremities. All three cases were studied with ultrasound (US), two with computed tomography (CT), and two with magnetic resonance (MR) imaging techniques. Two patients presented with multivesicular lesions which were considered diagnostic of hydatid disease. The third patient showed a lesion with a predominantly solid pattern, closely mimicking a soft-tissue neoplasm. US was not diagnostic, but MR outlined vesicular structures and a fibrous pericyst. Hydatid disease presenting in the soft tissues can therefore be diagnosed with confidence when it shows multi-vesicular lesions but MR may be the most useful imaging technique when a complex or solid pattern is present.