Cardiovascular system
A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha in Clark’s Procedures in Diagnostic Imaging: A System-Based Approach, 2020
The aorta is the largest artery in the human body and transports oxygenated blood from the heart to the rest of the body. The thoracic aorta consists of the ascending, arch and descending aorta. There are three major branches from the thoracic aorta, all from the aortic arch: the brachiocephalic, left common carotid and left subclavian arteries. The aorta passes into the abdomen through the diaphragmatic hiatus at T12. The abdominal aorta has three ventral branches (coeliac axis, superior mesenteric and inferior mesenteric arteries) and two lateral branches (right and left renal arteries). Figures 9.35a, b show the major branches of the thoracic and abdominal aorta. The abdominal aorta bifurcates into the right and left common iliac arteries, usually at the level of L4. Each common iliac artery further divides into the internal iliac artery, which supplies the pelvis, and the external iliac artery, which continues down the leg to become the common femoral artery (CFA) once it crosses below the inguinal ligament. A few centimetres below the inguinal ligament the CFA divides into the deep (profunda femoris, PFA) and superficial femoral (SFA) arteries.
Predicting the Biomechanics of the Aorta Using Ultrasound
Ayman El-Baz, Jasjit S. Suri in Cardiovascular Imaging and Image Analysis, 2018
Thoracic aortic disease continues to be associated with a significant burden of morbidity and mortality in the general population. Disease of the thoracic aorta is due to aneurysm and/or dissection. An aneurysm is by definition an aortic diameter twice the normal size. This can lead to frank rupture or dissection then rupture. A dissection is a tearing of the inner lumen of the aorta such that the layers of the media separate and blood flows into a false lumen as well as the true lumen. An aortic rupture and an ascending aortic dissection (Type A) are considered surgical emergencies. The mortality is high and generally over 50% are dead without surgical treatment within two weeks. Despite improvement in diagnostics and advanced surgical techniques, mortality rates following surgery for acute aortic syndromes such as a rupture or type A aortic dissection continue to be associated with an overall mortality of 20–25% and significant morbidity such as stroke [1–5]. This high mortality following acute life-saving surgery is contrasted by the much lower risk of mortality (1.5–2.5%) when the ascending aortic aneurysm is repaired electively [3, 4, 6, 7]. This comparison illustrates the critical importance of early detection of individuals at risk for acute aortic syndromes such as dissection and rupture. Currently, most aortic aneurysms are detected incidentally when undergoing imaging for an unrelated issue, as aortic disease is generally asymptomatic until a first presentation of catastrophic dissection or even sudden death [9]. At the present time, aortic size above a certain cut-off is generally the most widely accepted indication for elective aortic repair to prevent acute aortic syndromes.
The thorax
Professor Sir Norman Williams, Professor P. Ronan O’Connell, Professor Andrew W. McCaskie in Bailey & Love's Short Practice of Surgery, 2018
Although the most frequent indication for thoracotomy is lung cancer, all surgeons dealing with trauma should be able to perform a thoracotomy if required. The standard route into the thoracic cavity is through a posterolateral thoracotomy. The incision is used for access to the:lung and major bronchi;pleura;thoracic aorta;oesophagus;posterior mediastinum. A double-lumen endotracheal tube is used to allow ventilation of one lung while the other is collapsed, to facilitate surgery and to protect the non-operated lung and retain control of ventilation (Figure 55.18 ). The patient is turned to the lateral position with the affected side up (Figure 55.19 ). The lower leg is flexed at the hip and the knee, with a pillow between the legs. Table supports are used to maintain the position and additional strapping is used at the hips for stability. The patient’s hips are placed below the break point of the operating table to allow opening of the intercostal spaces as the table is angulated. The upper arm may be supported by a bracket in a position of 90° flexion. The lower arm is flexed and positioned near the head. It is important for both the surgeon and the anaesthetist to be completely satisfied with the position of the patient and the tube and lines at this stage.
A hybrid method based on level set and 3D region growing for segmentation of the thoracic aorta
Published in Computer Aided Surgery, 2013
Juan Antonio Martínez-Mera, Pablo G. Tahoces, José M. Carreira, Jorge Juan Suárez-Cuenca, Miguel Souto
This study sought to develop a completely automatic method for image segmentation of the thoracic aorta. We used a total of 4682 images from 10 consecutive patients. The proposed method is based on the use of level set and region growing, automatically initialized using the Hough transform. The results obtained were compared to those of manual segmentation as performed by an external expert radiologist. Concordance between the developed method and manual segmentation ranged from 92.79 to 95.77% in the descending regions of the aorta and from 90.68 to 96.54% in the ascending regions, with a mean value of 93.83% being obtained for total segmentation.
Uncertainty propagation of phase contrast-MRI derived inlet boundary conditions in computational hemodynamics models of thoracic aorta
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2017
Silvia Bozzi, Umberto Morbiducci, Diego Gallo, Raffaele Ponzini, Giovanna Rizzo, Cristina Bignardi, Giuseppe Passoni
This study investigates the impact that uncertainty in phase contrast-MRI derived inlet boundary conditions has on patient-specific computational hemodynamics models of the healthy human thoracic aorta. By means of Monte Carlo simulations, we provide advice on where, when and how, it is important to account for this source of uncertainty. The study shows that the uncertainty propagates not only to the intravascular flow, but also to the shear stress distribution at the vessel wall. More specifically, the results show an increase in the uncertainty of the predicted output variables, with respect to the input uncertainty, more marked for blood pressure and wall shear stress. The methodological approach proposed here can be easily extended to study uncertainty propagation in both healthy and pathological computational hemodynamic models.
Incidental descending thoracic aortic thrombus: the conundrum of medical versus surgical therapy
Published in Journal of Community Hospital Internal Medicine Perspectives, 2019
Kay Khine, Amit Toor, Koroush Khalighi, Mahesh Krishnamurthy
Background: A mural thrombus in the descending thoracic aorta frequently leads to distal organ and acute limb ischemia, increasing overall morbidity and mortality. Early diagnosis is imperative as thrombi are usually discovered after end organ damage has taken place. The formation of a mural thrombus in descending aorta has not been fully explained; however, the principle of Virchow’s triad for thrombogenesis (hypercoagulability, stasis of blood flow and endothelial injury) remains the likely pathophysiologic mechanism. Case Presentation: We present a case of a descending aortic thrombus incidentally detected on computed tomography scan in a 65-year-old female and successfully treated with anticoagulation, preventing subsequent complications. Conclusions: Suspicion for an aortic thrombus should arise when the origin is not known for acute onset distal limb or organ ischemia.
Related Knowledge Centers
- Abdominal Aorta
- Aorta
- Aortic Arch
- Aortic Hiatus
- Diaphragm
- Thoracic Vertebrae
- Posterior Mediastinum