ECG-gated multidetector computed tomography for the assessment of the postoperative ascending aorta

Purpose

This study was undertaken to define the role of electrocardiographically (ECG)-gated multidetector computed tomography (MDCT) in the assessment of the postoperative ascending aorta.

Materials and methods

From November 2006 to June 2007, 21 patients, [11 men, ten women; age ± standard deviation (SD): 62.7±10.8 years] with a history of ascending aorta replacement underwent ECG-gated MDCT and were prospectively included in our study. Ascending aorta replacement had been performed with different surgical techniques: Bentall-De Bono (four patients, 19%), Tirone-David (five patients, 23%), and modified Tirone-David with creation of aortic neosinuses (12 patients, 57%). Two patients were excluded from MDCT evaluation because they failed to fulfil the inclusion criteria. Transthoracic echocardiography was used as the reference standard. All patients provided informed consent.

Results

In all patients, ECG-gated MDCT provided a clear depiction of the aortic annulus, aortic root and ascending aorta, enabling accurate measurements in all cases. The aortic valve area (3.4±0.2 cm²), the diameter of the sinotubular junction (31.6±1.8 mm), the diameter of the neosinuses in the case of modified Tirone-David procedures (37.3±2.1 mm) and the distance between the cusps and the graft wall during systole (3.1±0.7 mm) fell within standard ranges and showed a good correlation (r=0.89) with the values obtained with transthoracic echocardiography.

Conclusions

MDCT is currently considered a compulsory diagnostic step in patients with suspected or known aortic pathology. MDCT is a reliable technique for anatomical and functional assessment of the postoperative aortic root and provides cardiac surgeons with new and detailed information, enabling them to formulate a prognostic opinion regarding the outcome of the surgical procedure.     

Diagnosis of ascending transtentorial herniation by cranial computed tomography.

The secondary effects of large infratentorial masses may include ascending transtentorial herniation. Rostral displacement of the superior vermis through the tentorial incisura can be accurately detected by cranial computed tomography. Signs of early or impending upward herniation are compression and slight posterior flattening of the quadrigeminal plate cistern. Progressively more severe herniation produces amputation of the peritcetal cerebrospinal fluid diamond, leading to a triangle or "squared off" appearance of the confluent quadrigeminal and superior cerebellar cisterns. When the disorder is severe, the herniated vermis plugs the incisura, completely effacing these cisterns and flattening the posterior third ventricle. Obstructive hydrocephalus may also occur with moderate or severe herniation.     

Compression of the right pulmonary artery by a dissecting aneurysm of the ascending aorta. Value of x-ray computed tomography

Right pulmonary artery compression by a dissecting aortic aneurysm-value of computed tomography. The authors relate a case of dissecting aortic aneurysm occurring as a late complication of aortic valve replacement and causing right pulmonary artery compression. Computed tomography appears to be performing technique for the exploration of this unusual case.     

Acute disease of the aorta. Diagnosis by computed tomography and ultrasonography

CT and ultrasonography, alone or in combination, have partially replaced aortography for the detection of abnormalities of the native and grafted abdominal aorta. In our medical center, ultrasonography is used to detect or confirm the diagnosis of aortic aneurysm and to determine its size, extent, and relationship to the renal arteries. We usually choose CT to assess suspected rupture of the native aorta and complications of the grafted aorta, such as occlusion, leakage, false aneurysm, or perigraft infection. Acute disease of the abdominal aorta can be detected or excluded using these relatively noninvasive imaging techniques.     

Evaluation of laryngeal cartilages by computed tomography.

Computed tomography of the larynx was performed in 21 patients and 3 anatomic specimens for evaluation of laryngeal cancer. Special attention was directed to the appearance of the laryngeal cartilages in both the normal and abnormal examinations in order to establish criteria for cancerous invasion. The problem presented by the normal nonuniformity of density of the cartilages is discussed in detail.     

Evaluation of pediatric hydrocephalus by computed tomography.

Computed tomography (CT) is a safe and reliable technique for the study of children with increased head circumference. Hydrocephalic children requiring drainage of cerebrospinal fluid may be shunted on the basis of the CT scan alone and their postsurgical course followed by serial CT scans thereafter. Any additional pneumographic studies required may be performed via the existing shunt tube, eliminating transcerebral catheterization and its attendant complications.     

Evaluation of intracerebral hematoma by computed tomography.

The CT scan appearances of acute intracerebral hematoma are usually diagnostic, and can be differentiated from hemorrhagic tumor and infarction. Some prognostic evaluations can be made, depending on the site and size of the hemorrhage. Sequential studies indicate resolution of the density of the hematoma over a period of approximately six weeks. This however does not appear to correlate with pathological resolution, but does reflect the hemoglobin concentration in the hematoma. Angiography is indicated when an underlying AVM or aneurysm is suspected, whereas contrast infusion studies are not of great value in detecting these lesions.     

Evaluation of traumatic rupture of descending aorta by aortography and computed tomography: case report with follow-up

Small aortic injuries are difficult to detect by computed tomography. We report a patient with a traumatic aortic injury that was not demonstrated on two high-resolution computed tomography scans 1 month apart despite prior angiographic demonstration of the lesion.     

Complications of central venous catheters diagnosed by computed tomography

Numerous reports of complications of central venous catheters have appeared in the literature. Most often these complications are diagnosed by plain or interventional radiography. Two cases are reported in which computed tomography was instrumental in diagnosing an abnormality that was not obvious on conventional radiography. This report demonstrates the value of this noninvasive technique for rapid and accurate evaluation.     

Prediction of the attenuation of the ascending aorta using bolus-tracking parameters and heart rate in coronary computed tomography angiography

Objective

The purpose of this study was to evaluate the correlation between bolus-tracking parameters and heart rate (HR) with attenuation of the ascending aorta and create a linear regression model for predicting coronary attenuation in coronary computed tomography angiography (CCTA).

Methods

A total of 50 patients (31 men, 19 women; mean age, 67.2 ± 10.8 y) underwent CCTA using a 320-detector CT scanner. A bolus-tracking scan was performed to optimize the scan timing. The average HR under normal breathing for 10 s was recorded just before the bolus-tracking scan started. Attenuation values of the pulmonary artery at 7 s (PA₇) and 10 s (PA₁₀) after the beginning of the injection were recorded during the bolus-tracking scan and the ascending aortic attenuation (CE_AAo) was measured during the diagnostic scan.

Results

A positive correlation was observed between PA₇ and CE_AAo (r = 0.41, P = 0.003) and PA₁₀ and CE_AAo (r = 0.66, P < 0.0001), and weak negative correlation was observed between HR and CE_AAo (r = −0.46, P = 0.15). A multivariable linear regression model for predicting CE_AAo was evaluated, and the residual error between the predicted and the measured CE_AAo was within approximately ±100 HU.

Conclusions

Coronary attenuation could be predicted using HR and pulmonary artery attenuation during the bolus-tracking method.     

Inflammatory aneurysm of aorta: development documented by computed tomography

Aortic aneurysmal disease appears to be the central focus of the inflammatory process resulting in inflammatory aneurysm formation. Some authors believe that inflammatory aortic aneurysm disease is a distinct clinicopathologic entity; however, others have included it with retroperitoneal fibrosis. The histologic features of inflammatory aneurysm suggest an immunologic basis for the lesion, with the atherosclerotic aorta as a possible source of the allergen.     

Evaluation of mucoceles of the paranasal sinuses with computed tomography.

Eighteen patients with mucoceles of the paranasal sinuses were studied by plain radiography, pluridirectional tomography, and computed tomography (CT). Sixteen of the lesions had a homogeneous appearance on CT but demonstrated variable absorption characteristics, with acutely infected mucoceles showing rim enhancement. Plain radiography and pluridirectional tomography were usually sufficient for making a diagnosis and defining the extent of the lesion, but CT more accurately demonstrated orbital and intracranial extension. Both transverse and coronal CT are essential for adequate evaluation.     

Evaluation of abdominal trauma by computed tomography

Computed tomography (CT) was used in the evaluation of 100 patients suffering abdominal trauma. The type of trauma was blunt in 78 patients, penetrating in eight, and iatrogenic in 14. Forty per cent of cases had normal CT scans, while 60% showed substantial abdominal or retroperitoneal injuries. Surgery, clinical follow-up, and repeated radiologic examinations confirmed the accuracy of CT, and there were no cases in which medical or surgical management was inappropriately guided by CT. A wide variety of injuries was detected, including 19 splenic, eight hepatic, six pancreatic, 13 renal, 13 retroperitoneal or abdominal wall, and one intraperitoneal. CT has major advantages over plain radiography, radionuclide imaging, and angiography in assessment of trauma-induced injuries.     

CT对肠系膜损伤的评价研究

目的 评价腹部CT对肠系膜损伤的诊断价值。方法 回顾14例经手术证实肠系膜损伤患者临床资料和CT检查结果，分析腹膜腔内游离积液、肠系膜脂肪内渗出、肠系膜血肿、造影剂血管外溢和肠壁增厚强化等CT征象，并结合手术结果确定CT表现对诊断肠系膜损伤的敏感性。结果 所有14例患者的CT图像均显示有腹膜腔游离积液或积血和肠系膜脂肪内渗出，其中12例可见肠系膜内血肿，2例显示有肠壁增厚强化，1例可见造影剂血管外溢，且CT表现与手术结果一致。结论 CT对于肠系膜损伤的诊断具有很好的敏感性，其CT表现有助于判断损伤的部位。     

Evaluation of Pott's disease with computed tomography

Summary The CT appearance of eight cases of culture-positive spinal tuberculosis is reviewed. Three patients had single level vertebral involvement, while five others showed multilevel involvement. In seven of eight cases, paraspinal soft tissue involvement was seen. In two, the process caused neurologic symptoms by extending into the epidural space. In three patients the paraspinal extension was not only local, but spread along multiple levels. The CT appearance can be highly suggestive of TB in cases where the diagnosis has not been suspected. In cases where the diagnosis is suspected by plain films, CT can display unsuspected extension of the disease and be helpful in needle localization for aspiration.