Multidetector-row Spiral CT Research Articles

Further evidence of a close anatomical relation between the oesophagus and pulmonary veins

Atrio-oesophageal fistula has been reported as a rare but life-threatening complication of ablation of atrial fibrillation (AF). Therefore, the position of the oesophagus in relation to the left atrium (LA) is of major importance for AF ablation. In order to investigate the possible anatomical variability between the oesophagus and the left atrium, multidetector-row spiral computed tomography (MDCT) of 60 healthy males (age 58.1+/-5.1 years; LA diameter 5.4+/-0.7 x 3.8+/-0.6 cm; LA volume 60.5+/-15.4 ml) was analyzed. The distance between the oesophagus and the ostia of the pulmonary veins (PV) ranged between 0 and 50.7 mm. Especially for the left PV, the oesophagus was closer than 5 mm to the ostia in 29 cases (48%; n = 24 for left superior PV; n = 10 for left inferior PV; n = 0 for right superior PV; n = 1 for right inferior PV). In addition, the oesophagus was very close to the LA wall (0.8+/-0.9 mm; range 0-3.3 mm). Intraobserver variability was 1.1+/-0.7 mm or 3.5%. The position of the oesophagus in relation to the LA and the PV demonstrates high variability. In many cases, the oesophagus is very close to the ostia of the PVs and lies only a short distance from the LA wall. Thus, an anatomical localization of the oesophagus may be critical before or during AF ablation to prevent atrio-oesophageal fistula, especially as there is a need for transmural atrial lesions.

Non-Invasive Imaging of Sutureless Vein Graft Anastomosis with 16-Slice Multi-detector Row Spiral Computed Tomography

Contrast-enhanced 16-slice multi-detector row spiral computed tomography (MDCT) has been shown to be useful for non-invasive visualization of aortocoronary bypass grafts (CABG). This new-generation scanner could be a good alternative to the common invasive coronary angiography. In this article, we report a patient operated on with the St. Jude Medical, Inc, Symmetry Bypass System (Aortic Connector System [ACS]) and subsequently studied by MDCT.

Left ventricular function studied with MDCT

Accurate determination of left ventricular (LV) myocardial function is fundamental for clinical diagnosis, risk stratification, and estimation of prognosis in patients with ischemic and nonischemic cardiomyopathy. Primarily, multi-detector-row spiral CT (MDCT) of the heart aimed at detecting coronary artery obstruction and cardiac morphology. Multiple studies have demonstrated that retrospectively, ECG-gated MDCT determination of LV volumes and consequently global LV function parameters is feasible in good agreement with established imaging modalities such as cineventriculography, echocardiography, and cine magnetic resonance imaging (CMR). Post-processing tools allow fast and semi-automatic determination of LV function parameters from MDCT data in analogy to known CMR evaluation approaches. Although MDCT is not considered to be first-line modality for LV function assessment, this technique provides accessory dynamic information in patients undergoing MDCT coronary angiography, contributing to combined assessment of cardiac morphology and function without need of additional radiation exposure. MDCT regional LV wall motion analysis at rest is feasible, but further improvement in temporal resolution seems mandatory to match results obtained from competing modalities. This paper will discuss the diagnostic potential of MDCT for assessment of LV function with regards to accuracy and clinical applications, as well as limitations, particularly in comparison with CMR as modality of reference.

Isquemia de ventrículo derecho y cor pulmonale

48 year old man with chronic obstructive pulmonary disease (COPD) secondary to pulmonary hypertension with domiciliary non-invasive ventilation was seen. He came to the emergency department with acute exacerbation of COPD. The patient was admitted to the Cardiology Service with the diagnosis of congestive heart failure. Diagnostic imaging (chest X-ray, transthoracic Doppler-echocardiography, multidetector row spiral CT and myocardial perfusion imaging) revealed an enlarged right ventricle. ECG was consistent with right ventricular failure. The heart perfusion imaging (pharmacologic stress testing with dobutamine) showed cor pulmonale and right ventricle ischemia induced by drug stress with dobutamine. Although right ventricle myocardial chronic dysfunction rarely causes right ventricular failure, it can occur when cor pulmonale and ischemia heart disease are present.

Imagerie de la trachée de l'adulte

Imaging of normal and pathologic trachea at the thoracic and cervical levels is described extensively. Beside congenital abnormalities discovered in adulthood, acquired tracheal abnormalities are artificially divided in two subgroups. One group consists of diffuse abnormalities, with all but one diseases associated with a diffuse narrowing of the tracheal lumen. The other group comprises focal abnormalities that lead to tracheal stenoses of various lengths, with a postintubation stenosis as probably the most frequent cause, followed by tumours. The main modality for tracheal imaging is now multidetector-row spiral CT. This technique allows for faster volume coverage and higher spatial and temporal resolution. The improved spatial resolution impacts on both axial images and all reconstructions techniques that have become indispensable for interpretation of a vertical structure such as the trachea. Chest X-ray is no longer the frontline imaging technique. MRI has not yet reached all its potential as compared to CT.

ECG-gated multi-detector row spiral CT in the assessment of myocardial infarction: correlation with non-invasive angiographic findings

Our objective was to retrospectively evaluate the ability of multidetector-row computed tomography (MDCT) to detect previous myocardial infarctions (MIs) and to correlate necrosis with the status of coronary arteries supplying the infarcted territory. After having clinically evaluated 187 patients referred for ECG-gated MDCT of the coronary arteries, 30 previous MIs were identified in 29 patients (9 recent and 21 chronic). MDCT data were evaluated qualitatively and quantitatively by measuring attenuation values and wall thickness within the infarcted region and normal adjacent myocardium. Each MI was also assigned to the distribution territory of a coronary vessel, and morphological data were combined with MDCT angiographic findings. MDCT was able to detect 25/30 MIs showing an overall sensitivity and specificity of 83 and 91%, respectively. Quantitative analysis revealed a statistically significant difference in attenuation values between normal and infarcted regions (38.9+/-14 HU vs. 104.0+/-16 HU). Regional wall thinning was observed in chronic MIs (4.1+/-2 mm vs. 10.5+/-3.8 mm), and not in patients with recent event (7.9+/-1.6 mm vs 9.1+/-4 mm). In 22/25 cases, MDCT angiographic findings showed the presence of suspicious critical lumen narrowing (n=3), previous coronary stenting (n=14) and surgical revascularization (n=5) in the infarct-related coronary. During a single examination, MDCT might provide comprehensive imaging of MI offering a combined morphological and angiographic assessment.

Clinical value of 16‐slice multi‐detector CT compared to invasive coronary angiography

Multi-detector row spiral CT (MDCT) can be applied as a noninvasive tool for the assessment of coronary artery stenoses. Few, confounding reports have been published using 16 detector rows. The aim of the present study was to determine the accuracy of 16-detector row MDCT for the detection of significant stenoses in the coronary arteries, in comparison to conventional invasive coronary angiography. Twenty-two patients with suspected coronary artery disease, were prospectively evaluated by 16-slice retrospectively ECG-gated CT coronary angiography and quantitative invasive coronary angiography. The findings were compared for the detection of significant coronary artery stenoses (>50%) in all segments with diameter >1.5 mm. MDCT correctly classified all 14 patients (100%) that were found to have significant coronary artery disease on conventional angiography. Overall, 288 segments were included in the analysis, regardless of their image quality. Significant stenoses were detected in 24 segments by CT and in 28 segments by conventional angiography. Out of 260 segments that were negative for significant stenoses on conventional angiography, 255 were correctly identified on CT. The sensitivity, specificity, positive and negative predictive values were 86, 98, 83 and 98%, respectively. MDCT also revealed supplementary findings that invasive angiography was unable to visualize, including anomalous vessel course, the course of vessels filling via collaterals, intramyocardial course of vessels and non-stenotic plaques. MDCT coronary angiography utilizing 16-detector rows shows promising results for reliable detection of coronary artery stenoses and particularly for ruling out significant disease.

Interrupted Aortic Arch Associated with Absence of Left Common Carotid Artery: Imaging with MDCT

Interrupted aortic arch (IAA) is a rare severe congenital heart defect defined as complete luminal and anatomic discontinuity between ascending and descending aorta. Although its association with various congenital heart defects has been reported, absence of left common carotid artery (CCA) in patients with IAA has not been reported previously. We report a case of IAA associated with the absence of left CCA which was clearly shown on multidetector-row spiral CT.

Diagnosing pulmonary embolism: time to rewrite the textbooks

Computed tomography (CT) is rapidly becoming the first line modality for imaging pulmonary embolism (PE). However, limitations for the accurate diagnosis of small peripheral emboli have prevented the unanimous acceptance of CT as the new standard of reference for imaging PE although the actual significance of the detection and treatment of isolated peripheral emboli is uncertain. At the same time the high negative predictive value of CT pulmonary angiography for excluding clinically significant PE has been established in retrospective and prospective studies. The introduction of multidetector-row spiral CT has greatly improved visualization of peripheral pulmonary arteries and detection of small emboli. Previous concerns regarding the accuracy of spiral CT for the accurate diagnosis of peripheral pulmonary emboli should thus be overcome. Multidetector-row spiral CT has become a widely available and cost-effective modality, which has surpassed other imaging modalities for PE diagnosis to a point where over-utilization may become of concern. Our most immediate goal must be to educate our referring colleagues about these important transitions so that the diagnostic algorithm in patients with suspected acute PE is updated to accurately reflect our current diagnostic prowess in medical imaging.

The Utility of Multi-detector Row Spiral CT for Detection of Coronary Artery Stenoses

Contrast-enhanced multi-detector row spiral computed tomography (MDCT) was introduced as a promising noninvasive method for vascular imaging. This study examined the accuracy of this technique for detecting significant coronary artery stenoses. Both MDCT(Sensation 16, Siemens, Germany, 12 × 0.75 mm collimation and 0.42 sec rotation speed, 120 kV, 500 effective mA, and 2.7 mm/rotation table-feed) and invasive coronary angiography (CAG) were performed on 61 patients (mean age 59.2 ± 10, 44 men) who were suspected of having coronary artery disease. All patients were treated with atenolol (25 - 50 mg) prior to imaging and the heart rate was maintained below 65 beats per minutes during image acquisition. The images were reconstructed in the diastole around TI - 400 ms with a 0.5 mm increment and a 1.0 mm thickness. All coronary arteries with a diameter of 2.0 mm or more were assessed for the presence of a stenosis (> 50% luminal narrowing). Two independent radiologists who were unaware of the results of the invasive CAG evaluated the MDCT data, and the results were compared with those from the invasive CAG (interval 1- 27, mean 11 days). An evaluation of the CT coronary angiogram (CTCA) was possible in 58 of the 61 patients (95%). Image acquisition of the major coronary arteries including the left main trunk was available in 229 out of 244 arteries. Invasive CAG showed that 35 out of 58 patients had significant coronary artery stenoses by. patient analysis of those who could be evaluated showed that CT coronary angiography correctly classified 30 out of 35 patients as having at least 1 coronary stenosis (sensitivity 85.7%, specificity 91.3%, positive predictive value 93.8%, negative predictive value 80.8%). By analyzing each coronary artery, CAG found 62 stenotic coronary arteries in the 229 coronary arteries that could be evaluated. MDCT correctly detected 50 out of 62 stenotic coronary arteries and an absence of stenosis was correctly identified in 156 out of 167 normal coronary arteries (sensitivity 80.6%, specificity 93.4%, positive predictive value 81.9%, negative predictive value 92.8%). The non-invasive technique of MDCT for examining the coronary artery appears to be a useful method for detecting coronary artery stenoses with a high accuracy particularly with the proximal portion and large arteries.

A Study of Inter-observer Agreements of Spiral Chest Computed Tomography in Diagnosing Pulmonary Embolism

Background : A pulmonary embolism often presents with nonspecific symptoms and signs. However, a delayed diagnosis can result in catastrophic outcome. The majority of preventable deaths associated with a pulmonary embolism can be ascribed to a missed diagnosis rather than to the failure of existing treatments. Therefore, accurate and rapid diagnostic methods are essential for the management of a pulmonary The recent generation of multidetector-row spiral CT scanners appears to outperform other imaging modalities in detecting a central and peripheral pulmonary However, there are some variations in the interpretations of the findings between observers. This study examined the inter-observer differences of the diagnoses in patients with a pulmonary Method : 64 patients who were diagnosed with a pulmonary embolism either clinically or with spiral chest CT from 2002 to 2004, were included. Two thoracic radiologists interpreted the multidetector-row spiral CT in terms of the diagnosis of a pulmonary embolism and the location of the thrombus independently. Among 64 patients, 14 patients were excluded because there was no evidence of a pulmonary embolism or there was different interpretation of the pulmonary embolism between radiologists. A clinical diagnosis was based on Rules for predicting the probability of embolism. Results : The mean score of the patients according to the Wells method was (0-9). The accordance of the radiologists was 95% in the main, 85% in the lobar, 91.2% in the segmental, and 96% in the sub-segmental pulmonary arteries. After excluding the negative interpretation from both radiologists, their agreement was 76.2%( 0.83) in the main, 57.6%( 0.63) in the lobar, 51.5%( 0.63) in the segmental, and 34.6%( 0.49) in the sub-segmental pulmonary arteries. Conclusion : Chest CT has been recently applied to patients suspected of having a pulmonary It was found that spiral CT is a rapid test for diagnosing a thrombus, and there was reliable accordance between the observers from the area of the large pulmonary arteries. However, there was a lack of agreement between the observers in diagnosing thrombi located distal to the sub-segmental arteries.

Spiral CT for Pulmonary Embolism: the Paradigm Has Shifted

Computed tomography (CT) is rapidly becoming the first-line modality for imaging pulmonary embolism (PE). However, limitations for the accurate diagnosis of small peripheral emboli have prevented the unanimous embrace of CT as the new standard of reference for imaging PE, although the actual significance of isolated peripheral emboli is uncertain. At the same time, the high negative predictive value of CT pulmonary angiography for excluding clinically significant PE has been established. The introduction of multidetector-row spiral CT has greatly improved visualization of peripheral pulmonary arteries and detection of small emboli. Previous concerns regarding the use of spiral CT for the accurate diagnosis of peripheral pulmonary emboli should thus be overcome. Multidetector-row spiral CT has become a widely available and cost-effective technology and appears to have surpassed other imaging modalities for the accurate detection of central and peripheral PE. In this review, the authors assess the current role of spiral CT in the diagnostic algorithm of PE.

Long-residence-time nano-scale liposomal iohexol for X-ray-based blood pool imaging.

Although soluble nonionic iodine compounds with low systemic toxic effects have been developed for use in computed tomography (CT), they have short residence times of a few minutes or mere seconds-insufficient time for blood pool imaging, even with high-speed multi-detector row spiral CT. Moreover, potential renal toxic effects preclude repeated administration of these contrast agents during imaging, as well as their use in patients with compromised renal function. The objective of this study was to develop and evaluate a CT contrast agent for blood pool imaging that remains in the blood for more than 3 hours and that is relatively nontoxic to the kidneys. The authors assessed a liposomal iohexol formulation for its encapsulation efficiency in terms of milligrams of iodine per milliliter of lipid formulation and for its stability in phosphate buffer solution and in human plasma in vitro. Using a rabbit model, they also assessed the formulation's in vivo stability, residence time, and enhancement of contrast on images of various organ systems. The formulation, which contained 34.8 mg of iodine per milliliter of liposomal iohexol solution, remained stable in blood plasma both in vitro and in vivo, after injection into rabbit vasculature. An intravenous dose of 475 mg of iodine per kilogram of body weight produced contrast enhancement in the rabbit model of approximately 130 HU in the aorta and liver cortex and approximately 100 HU in the kidney cortex. Contrast enhancement was maintained for 3 hours after injection, and minimal clearance of the contrast agent via the kidneys was observed. The liposomal iohexol formulation tested in this study had a sufficient residence time for blood pool imaging in a rabbit model. Future experiments with long-residence-time iohexol formulations may lead eventually to applications in cardiac imaging and in early tumor detection.

CO 2-Enhanced CT Imaging for the Detection of Pulmonary Emboli : Feasibility Study in a Porcine Model

Rationale and Objectives The authors investigated the feasibility of using computed tomography (CT) with CO 2 gas as a negative contrast agent for detecting pulmonary emboli in a porcine model. Materials and Methods Seven pigs with or without pulmonary emboli underwent thoracic imaging with multi–detector row spiral CT. To identify optimal injection and scanning protocols, the first four pigs were scanned repeatedly in the supine and prone positions with different scan delays (10, 15, and 20 seconds) and different volumes of CO 2 (60, 120, 180, and 240 mL), which were hand infused (each infusion took 10–15 seconds). The last five pigs with emboli were scanned with iodinated contrast medium and then rescanned with 120 or 180 mL of CO 2. The CO 2 volumes and scan delays were qualitatively assessed. The supine and prone CT scans and the number and location of thrombi depicted in the CO 2- and contrast material–enhanced CT scans were compared. Results Because the pulmonary artery in pigs is in the posterior anatomy, the prone position was more effective than the supine position with CO 2 enhancement. An infusion of 120 mL of CO 2 was sufficient to enhance the entire pulmonary artery, and scanning timed to coincide with the completion of infusion was the most effective. Both the CO 2- and con-trast-enhanced CT scans demonstrated all thrombi. Thrombi were more apparent on the CO 2-enhanced CT scans than on the contrast-enhanced scans because of the high contrast interface between soft tissue and gas. However, two of the seven pigs with thrombi experienced abrupt cardiac arrest after CO 2-enhanced scanning and could not be resuscitated. The cause of these events was not determined in the current study. Conclusion The CT depiction of pulmonary emboli is feasible with CO 2 gas as a negative contrast agent and may even be superior to that with iodinated contrast media. Further studies are required to evaluate the safety of this method and to develop an improved delivery of CO 2 gas for this application.

Use of three-dimensional computed tomographic angiography of pulmonary vessels for lung resections

Background Identification and appropriate treatment of the pulmonary artery (PA) is a key to successful anatomic resection of the lung. Preoperative identification of branching pattern of the PA seems to make pulmonary resection easier and safer especially when there is severe adhesion or incomplete fissure between the lobes. With the development of the multidetector row spiral computed tomography (MDCT), three-dimensional (3D) CT angiography can be obtained easily and can provide very useful information about various organs. We studied the usefulness of 3D-CT pulmonary angiography (3D-CTPA) in evaluating the PA branching pattern before anatomic pulmonary resection. Methods Fourteen patients with primary lung cancer undergoing anatomic pulmonary resections were the subjects of this study. The 3D-CTPA images were obtained using MDCT. The obtained images of the PA branching pattern were compared with intraoperative findings in each case at the time of thoracotomy. Results MDCT scanning required approximately 15 seconds per patient during a single respiratory pause and the 3D images were processed within 10 minutes after scannning. According to intraoperative findings, 98% (84 of 86) of PA branches were revealed to be successfully identified on preoperative 3D-CTPA. Two missed branches on 3D-CTPA were small vessels, which were less than 1.5 mm in actual diameter. Pulmonary vessels were clearly identified even when contrast medium was not administered intravenously. Conclusions Obtaining 3D-CTPA using MDCT is noninvasive yet it provides precise preoperative information regarding pulmonary vessels. This technique is a far less invasive and an easier investigation than conventional pulmonary angiography. The 3D-CTPA navigation may have the potential to increase the safety of surgical procedure and to reduce surgical morbidity in anatomic lung resection.

Peripheral pulmonary arteries: how far in the lung does multi-detector row spiral CT allow analysis?

To analyze the influence of multi-detector row spiral computed tomography (CT) on identification of peripheral pulmonary arteries. Peripheral pulmonary arteries were analyzed on optimally opacified contrast material-enhanced spiral CT angiograms in 30 patients devoid of pleuroparenchymal disease who underwent scanning with multi-detector row CT (collimation, 4 x 1 mm; pitch, 1.7-2.0; scanning time, 0.5 second). Two series of scans were systematically generated from each data set, 1.25-mm-thick (group 1) and 3-mm-thick (group 2) sections, leading to the analysis of 600 segmental (20 arteries per patient), 1,200 subsegmental (40 arteries per patient), 2,400 fifth-order (80 arteries per patient), and 4,800 sixth-order (160 arteries per patient) pulmonary arteries in each group. Multi-detector row CT with reconstructed scans of 1.25-mm-thick sections (group 1) allowed (a) analysis of a significantly higher percentage of subsegmental arteries (94% in group 1 vs 82% in group 2; P <.001) and (b) a significantly higher percentage of fifth- and sixth-order arteries, respectively, identified in 74% and 35% of cases in group 1 and 47% and 16% in group 2 (P <.001). The causes for inadequate depiction of subsegmental branches in group 1 were partial volume effect (43%), anatomic variants (39%), and cardiac (17%) and respiratory (1%) motion artifacts. Multi-detector row CT with reconstructed scans of 1.25-mm-thick sections enables accurate analysis of peripheral pulmonary arteries down to the fifth order on spiral CT angiograms.