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A foetal echocardiogram, in a 27-week foetus referred for cardiomegaly, demonstrated dextrocardia, absence of the ductus venosus, and an unrestricted unusual umbilical venous drainage to a left posterior intercostal vein, which continued to left hemiazygos vein and drained into the coronary sinus. Progressive cardiomegaly led to early delivery. To the best of our knowledge, no case with similar umbilical venous drainage has been previously reported.

Some patients with intestinal failure, who are dependent on total parenteral nutrition for long periods, suffer from a lack of suitable conventional venous access points, including axillary, external jugular, internal jugular, subclavian, saphenous, and the brachio-cephalic and femoral veins, due to their occlusion. Furthermore, extensive central venous stenosis and/or thrombosis of the superior and inferior vena cava may preclude further catheterization, so uncommon routes must be used, which can be challenging. In such patients, the azygos vein via the intercostal vein is a viable candidate. Thoracotomy-assisted, thoracoscopy-assisted, and cut-down procedures are currently suggested such access. We found that ultrasound-guided percutaneous puncture method was a safe and minimally invasive approach and successfully placed two central venous lines in preparation for small bowel transplantation via two different intercostal veins (ninth and tenth). Although the lung was actually located just below the target veins, an ultrasound provided augmented and clear vision, which contributed to the safe performance of the procedure without the need for invasive surgical intervention, such as thoracotomy, thoracoscopy, or rib resection using the cut-down technique. Furthermore, constant positive-pressure ventilation during vein puncture under general anesthesia also helps avoid venous collapse. Despite carrying a slight risk of light injury to the lung, artery, and nerve along with the vein compared to other procedures, we believe that ultrasound-guided puncture under general anesthesia is feasible as a minimally invasive method.

Azygos system of veins is the main source of venous drainage from the thoracic wall. Knowledge of azygos vein anomalies could be of importance to cardiothoracic surgeons and radiologists. We report a rare variation of azygos vein as seen in an adult male cadaver aged 65 years approximately. The azygos vein was formed by the union of left ascending lumbar and subcostal veins. It coursed upwards on the left side of descending thoracic aorta and crossed the left subclavian artery and the left vagus to terminate into the left brachiocephalic vein. It received left superior intercostal vein and left fifth to eleventh posterior intercostal veins. The hemiazygos and accessory hemiazygos veins were situated on the right side of the vertebral column. They received the right posterior intercostal veins and terminated into the azygos vein at the level of eighth thoracic vertebra.

The superior vena cava is formed during the fetal period by the development of anastomoses between the right and left anterior cardinal veins, and the regression of the central part of the left anterior cardinal vein. The persistence of this part of the left anterior cardinal vein causes the formation of a left superior vena cava, which is a rare anomaly in cadaver dissection. We report the case of a persistent left superior vena cava with a normal right superior vena cava in a 95-year-old male cadaver, which was discovered during anatomical dissection for medical students at Kawasaki Medical School in 2016. The left superior vena cava was formed by the confluence of the left internal jugular and left subclavian veins and terminated in the right atrium via what would normally be the coronary sinus. The right and left superior venae cavae received intercostal veins via a right and left azygos vein, respectively. However, the right azygos vein was shorter than the normal azygos vein and received only the second to fifth intercostal veins, whereas the left azygos vein received the fifth to eleventh left intercostal veins and the sixth to eleventh right intercostal veins. We consider that the anomalies of the azygos venous system were the result of regression of right supracardinal vein and the persistence of the left supracardinal vein during development. An awareness of such variations of major thoracic veins is important for the interpretation of unusual CT images.

Introduction The azygos system of veins (ASV) is a very variable structure characterized as a communication between the inferior and superior vena cava, having the azygos vein (AV), the hemiazygos vein (HV), and the accessory hemiazygos vein (HAV) as its main components, which are responsible for the mediastinal viscera and for the thoracoabdominal wall drainage. The aim of the present study is to report an anatomical variation found in a male cadaver at the Laboratory of Anatomy of the University Center of UNIFACISA, Campina Grande, PB, Brazil. Case Report In the posterior mediastinum, the union of the HV, of the HAV, and of the 8th left posterior intercostal vein formed a common trunk at the level of the left 8th intercostal space, crossing the mediastinum posterior to the aorta artery, ending up in the AV, in the right hemithorax. Conclusion The study of the anatomical variations of the ASV is important and will provide knowledge for physicians not to confuse them with pathological processes in imaging exams. Moreover, it can provide safety in surgical approaches of the thorax.

During an educational dissection of a 72-year-old Chinese male cadaver, the hemiazygos vein (HAV) coursing the left side that drains into the persistent left superior vena cava was observed. The HAV was formed at the junction of the 9th to 11th right posterior intercostal veins, right subcostal vein, 5th to 11th left posterior intercostal veins, and left subcostal vein; it then ascended posteriorly to the thoracic aorta. After collecting the accessory hemiazygos vein, it crossed over the aorta and the pedicle of the left lung via the hemiazygos arch, then converged with a communicative branch (vein of Marshall) that emerged from the left brachiocephalic vein to form the persistent left superior vena cava and entered the pericardium at the level of the sixth thoracic vertebra. Upon opening the pericardium of our cadaver, the persistent left superior vena cava was found to drain directly into the significantly dilated coronary sinus at the level of the eighth thoracic vertebra. The azygos vein was formed by the union of the first to eighth right posterior intercostal veins and appeared to be finer and shorter than the HAV. The persistent left superior vena cava might be the result of incomplete degeneration of the left posterior cardinal vein. Knowledge of such variations could be of great value to surgeons placing peripherally inserted central catheters because incorrect placement of the azygos venous system can be detrimental to the patient. In addition, during heart surgery, awareness of such variations may prevent major complications, such as hemorrhage or damage to vascular structures, and possibly also provide new insights and perspectives to cardiovascular surgeries.

Knowledge of variations of azygos and hemiazygos veins is of importance to cardiothoracic surgeons and radiologists during various surgical, radiological, and echography techniques. We report some unique variations of azygos system of veins observed during dissection classes for undergraduate medical students. The azygos vein was formed as usual by the union of right subcostal and ascending lumbar veins. The vein ascended upward and to the left to reach the midline at the level of the 9th thoracic vertebra. After ascending till 5th thoracic vertebra, it gradually inclined to the right of midline and terminated by opening into the superior vena cava at the level of the 3rd thoracic vertebra. There was no major variation in the tributaries of the azygos vein on the right side, except that the right superior intercostal vein crossed behind the azygos vein from right to left and opened into the left side of the azygos vein. Further, two anastomotic veins connected the 10th, 11th and 12th posterior intercostal veins with each other to form two anastomotic circles on the right side of 10th to 12th thoracic vertebrae. The hemiazygos vein bifurcated on the left side of the 10th thoracic vertebra and the two ends opened into the azygos vein at the level of 9th and 10th thoracic vertebrae forming a venous circle in front of the 10th thoracic vertebra. The course of accessory hemiazygos vein was noteworthy. Instead of its classic descending course, the vein ascended upward from the left side of the 8th thoracic vertebra till the 6th thoracic vertebra before opening into the azygos vein.

Azygos venous system drains the venous blood from thoracic wall. Knowledge of variations of its course and tributaries is important to cardiothoracic surgeons, radiologists and orthopedic surgeons. We observed the following variations in the azygos veins. Both azygos and hemiazygos veins were formed by union of lumbar azygos and subcostal veins of corresponding sides. The ascending lumbar vein did not drain into the azygos system. The hemiazygos vein had a larger diameter than the lower part of azygos vein and it joined azygos vein at the level of seventh thoracic vertebra. Accessory hemiazygos vein was totally absent. The azygos vein received 4th to 11th right posterior intercostal veins and also received 3rd to 6th left posterior intercostal veins. Hemiazygos vein received 7th to 11th left posterior intercostal veins.

The aim of this study was to describe the possible variations in the connection between the internal venous vertebral system and the cranial vena cava in rabbit using corrosion technique. The study was carried out on 40 adult New Zealand white rabbits. The venous system was injected by using Batson's corrosion casting kit number 17. We found the connection between the internal venous vertebral system and the cranial vena cava by means of the vertebral veins and the right azygos vein. The vertebral vein was present as independent tributary in 36 cases (90%). In the rest of the cases, it was found as being double, being triple, or forming a common trunk with other veins. The azygos vein was present as independent tributary of the cranial vena cava in 39 cases (97.5%). We found also a common trunk formed by the junction of the deep cervical vein, the right vertebral vein, and the azygos vein in one case (2.5%). The azygos vein received 6, 7, 8, or 9 pairs of dorsal intercostal veins. Documenting the anatomical variations in the rabbit will aid in the planning of future experimental studies and determining the clinical relevance on such studies.

Atypical anatomy may be encountered unexpectedly and undiagnosed in clinical practice, and this is especially important during the performance of interventional procedures such as transvenous implantation of cardiac electronic devices. The body of the first rib can be absent. If this not noticed, pneumo-/haemothroax may be induced during subclavian vein puncture as the needle may enter the first intercostal space rather than the costo-clavicular angle. The cephalic vein may pursue a supraclavicular course, the axillary vein may drain into an intercostal vein rather than the axillary vein, and the entire length of the axillary-subclavian-brachio-cephalic vein may be absent. Device implanters should be vigilant about the possibility of these anatomical variations, and be equipped with the knowledge and spectrum of alternative techniques needed to deal with them.

Objective: The purpose of our investigation was to determine the safety and usefulness of embolisation procedures in balloon occluded retrograde transvenous obliteration (BRTO) as treatment of gastric varices after portal hypertension. Materials and Methods: Between June 2004 and August 2009, 40 patients underwent BRTO for gastric varices that occurred after portal hypertension in our institution. When large collateral vessels of gastric varices had developed as drainage veins other than the gastro-renal shunt, these collateral vessels were embolised prior to BRTO. Results: Embolisation was performed for 18 collateral vessels in 16 cases before BRTO. Embolised collateral vessels were the left inferior phrenic vein (n = 14), intercostal vein (n = 3), and ascending lumbar vein communicating with the gastro-renal shunt (n = 1). Mean number of micro-coils used was 5.7 in left inferior phrenic veins, 4.7 in intercostal veins and 4 in the ascending lumbar vein. In 36 (90%) patients, contrast-enhanced abdominal CT after BRTO showed that the gastric varices were well obliterated. The rate of occurrence of cases in which the remnant of the enhanced area in the gastric varices was seen even after BRTO was statistically higher in cases requiring embolisation of collateral vessels than in those who did not (4/16 versus 0/24, P = 0.0199 according to Fisher's exact probability test). Recurrence of gastric varices was determined by endoscopy in 1 (2.5%) case necessitating embolisation of collateral vessels. There were no serious complications. Conclusion: Embolisation of collateral vessels before BRTO is a safe and useful procedure. However, especially in cases having collaterals sufficiently large to require embolisation, careful follow-up for recurrence of gastric varices is necessary.

Objective The superior vena cava (SVC) obstruction by malignant diseases is either by direct invasion and compression or by tumour thrombus of the SVC. Whatever is its cause, obstruction of the SVC causes elevated pressure in the veins draining into the SVC and increased or reversed blood flow through collateral vessels. Severity of the syndrome depends on the collateral vascular system development. Therefore, imaging of the collateral veins with variable location and connection is important in determining the extension and management of the disease. Our aims are to describe collateral vessels of the superior vena cava syndrome (SVCS) related with the malignant diseases and to assess the ability of multi-detector row CT with multiplanar and 3D volume rendering techniques in determining and describing collateral circulations. Materials and methods We present CT angiography findings of seven patients with small cell carcinoma of the lung (n = 2), squamous cell carcinoma of the lung (n = 3), Hodgkin disease of the thorax (n = 1), and squamous cell carcinoma of the oesophagus (n = 1). The patients received contrast-enhanced CT scans of the chest and abdomen on a multi-detector row CT during breath holding at suspended inspiration. Results CT images revealed the cause and level of the SVC obstruction in all patients with axial and multiplanar reconstructed images. The SVC showed total obstruction in five patients and partial obstruction in two patients. The most common experienced collateral vessels were azygos vein (6), intercostal veins (6), mediastinal veins (6), paravertebral veins (5), hemiazygos vein (5), thoracoepigastric vein (5), internal mammary vein (5), thoracoacromioclavicular venous plexus (5), and anterior chest wall veins (5). While one case showed the portal-systemic shunt, V. cordis media and sinus coronarius with phrenic veins were enlarged in two cases, and the left adrenal vein was enlarged in a patient. In one case, the azygos vein with reversed blood flow was drained into both inferior vena cava and hemiazygos vein with the left renal vein. Conclusion Multi-detector row CT with multiplanar and 3D imaging is an effective tool in evaluation of the SVCS and has a greater advantage than the other imaging techniques. 3D volume rendering is a useful technique in determining and describing collateral circulations in addition to the primary disease process.

Background/Purpose Some children dependent on total parenteral nutrition for long periods have no more axillary, internal jugular, external jugular, saphenous, and femoral veins available for cannulation. In such patients, the central venous system can still be accessed via the azygos vein by placing an implantable port catheter through one of the right posterior intercostal veins. This is the first known description of such procedure. Methods We report the use of the second and third right intercostal veins for placement of the catheter by right intrapleural thoracotomy in 2 pediatric patients with short gut syndrome. Results Recovery from the thoracotomy was uncomplicated, and the patients could receive complete intravenous nutritive mixtures immediately after the insertion of the catheter. Both patients remain dependent on total parenteral nutrition and are awaiting an intestinal transplantation. Conclusion The knowledge of alternate routes to obtain central venous access for prolonged parenteral nutrition is critically important, and the azygos system can be used when more accessible veins are unavailable.

The arteries and veins of the left vagus (VN) and left recurrent laryngeal (RLN) nerves from the thoracic inlet to the subaortic region are described following vascular casting with red colored latex in 6 adult fresh non-embalmed cadavers. In all specimens the anterior bronchoesophageal artery supplied at least one vessel to the VN and RLN in the subaortic region. For the RLN other arterial sources were arteries arising from the aortic arch in 1 specimen, the subclavian artery in 3 specimens, the first intercostal artery in 1 specimen, and the inferior thyroid artery in all specimens. For the VN other arterial sources were arteries arising from the aortic arch in 2 specimens and the inferior thyroid artery in 1 specimen. For both the VN and RLN the veins were located under the pleura and directed towards the internal thoracic vein anteriorly and the thoracic intercostal veins posteriorly. In conclusion, the inferior thyroid artery at the thoracic inlet for the RLN and the anterior bronchoesophageal artery are the more consistent vessels supplying the VN and RLN. Vascular damage occurring during mediastinal lymph node excision to the VN and RLN, especially in the subaortic region, may explain postoperative vocal fold paralysis.

We report the case of a neonate born at 384/7 weeks of gestation with median birth weight and size and in the 75th percentile for head circumference. Routine pregnancy follow up allowed the antenatal discovery of azygos continuation with absence of the inferior vena cava.

A 28-year-old man with a persistent cough and a mild fever was transferred to our institution. Computed tomography angiography showed a giant azygos venous aneurysm associated with the dilation of lumbar veins, azygos veins, hemiazygos veins, and intercostal veins (A-D). At the ages of 3 and 18 years, the man had undergone resection of angiomas in the chest wall (approximately 8 8 7 cm) and on the back (approximately 10 8 8.5 cm), respectively. The pathologic diagnosis showed cavernous hemangioma and lymphangioma. After the second operation, he was subsequently injected with ureaphil every 3 months for 18 times in total. However, the computed tomography scan at that time did not show the visible dilation of azygos veins and fertile varicose veins including intercostal veins, lumbar veins, and partial visceral veins, which was significantly different from that of 10 years later. Azygos venous aneurysms are extremely rare. Nakamura et al reported three main types of azygos venous aneurysms caused by different factors. One of them was dilation of the azygos vein induced by increased venous pressure and volume load, as in the cases of heart failure, portal hypertension, right atrial mural thrombosis, and inferior vena caval occlusion. In this case, we believe it was induced by resection of hemangioma, which increased pressure and volume load. To the best of our knowledge, the giant azygos venous aneurysm caused by resection and embolization of cavernous hemangioma in the chest wall and back has never been reported. Azygos venous aneurysms may also be related to traumatic pseudoaneurysm and idiopathic saccular aneurysm. Its differential diagnosis should include other posterior mediastinal masses. However, Gomez et al reported that if it is thrombosed, surgical therapy is necessary to prevent pulmonary embolism. A video-assisted thoracoscopic excision is recommended as the best technique.

Multiple variations of the azygos venous system were detected during routine dissection. The hemiazygos vein was underdeveloped. On the left side of the thorax, posterior intercostal veins between the 8th and 11th intercostal spaces and the subcostal vein drained into the azygos vein independently. In addition, the posterior 4th, 5th, 6th and 7th intercostal veins united and formed two superior and inferior trunks. The superior common trunk, at the level of the T4 vertebra, crossed the vertebral column obliquely, lying anterior to the aorta and posterior to the esophagus, opening into the azygos vein at the level of the T4 vertebra. The other structures in this part were normal. There were different courses of the azygos vein system. This variation is important in mediastinal surgery and also in the interpretation of radiographs.

Some children requiring chemotherapy, total parenteral nutrition, or repeated blood sampling for long periods have no more axillary, internal jugular, external jugular, saphenous, or femoral veins available for cannulation. In such patients, the central venous system can still be accessed via alternate routes e.g. the azygos vein, the gonadal vein or the inferior epigastric vein.We report the use of: 1) The inferior epigastric vein for placement of the catheter into the IVC in 20 patients. 2) The right gonadal vein for placement of the catheter using a retroperitoneal approach in five pediatric patients. 3) The second and third right intercostal veins for placement of the catheter by right intrapleural thoracotomy in five pediatric patients. Pre-procedural assessment of the patency of these veins was done using colour Doppler ultrasonography and confirmation of occlusion of common sites used for central venous access.A total of 38 implantable venous access devices (IVAD) were inserted in 30 patients. The average age at operation was 1.4 years (range 1 month to 12 years). Infection was seen in two patients, venous thrombosis in two. The average longevity of IVAD is 6.5 months. Recovery from the procedure was uncomplicated and the patients were able to receive complete intravenous medication or nutritive mixtures after the insertion of the catheter.The knowledge of alternate routes to obtain central venous access for children requiring chemotherapy, total parenteral nutrition, or repeated blood sampling for long periods is critically important, and the azygos system, right gonadal vein or the inferior epigastric vein can be used when standard accessible veins are unavailable.

The uppermost portion or arch of the azygos vein is frequently ligated and divided in thoracic surgery. The hemodynamic effects arising from this proce dure have not, however, been described previously. The authors assessed such effects by using transesophageal real-time two-dimensional Doppler echography (TE2DD). Nine patients, whose azygos arch had been ligated and divided in the course of surgery for lung cancer, were examined. The intervals between the prior operation and the examination with TE2DD ranged from one to fifty months. By use of a convex array transducer with a frequency of 7.5 MHz, the hemodynamics of both the azygos vein and the intercostal veins, which join the former, were assessed. The esophagopetal portion of the azygos vein could be visualized in color in 6 of 9 cases. In all these 6 cases, the flow direction of the azygos vein was reversed and directed caudally. Blood flow in both the azygos vein and the intercostal veins is normally pulsatile. After ligation, however, it had become constant in 3 of 5 cases analyzed by pulsed Doppler spectrum. The value of mean flow velocity in the azygos vein (9 ± 5 cm/sec) was significantly (p < 0.05) smaller than that of the control group (15 ±5 cm/sec).

We illustrate the spectrum of venous collateral pathways caused by the thoracic central venous obstruction with direct spiral computed tomography (CT) venography and 3-dimensional reconstruction images. Venous structures that can be demonstrated with CT venography include the jugular veins; the subclavian and brachiocephalic (innominate) veins; the internal and lateral thoracic veins; the superior and inferior venae cavae; the pericardiophrenic veins; the azygos, hemiazygos, and accessory hemiazygos veins; and the intercostal veins.

Multi-detector row computed tomography (CT) and volume rendering can be used as an interpretive aid to present the systemic and pulmonary venous anatomy of the thorax. Both of these venous systems are routinely imaged in clinical practice and are important in interpretation of diagnostic images in health and disease. Multi-detector row CT and three-dimensional volume rendering provide high-quality near-isotropic data (ie, the longitudinal resolution approximates the in-plane resolution). The data sets allow tailored postprocessing to produce images optimized for these vessels, which are often not fully appreciated at planar axial imaging alone. Venous structures of the thorax that can be demonstrated with multi-detector row CT and volume rendering include the jugular veins; the subclavian and brachiocephalic veins; the internal and lateral thoracic veins; the superior and inferior venae cavae; the coronary sinus, the cardiac and pericardiophrenic veins, and vein grafts; the azygos, hemiazygos, and accessory hemiazygos veins; the intercostal veins; the pulmonary veins; and other thoracic veins.

Central venous lines are of particular importance in seriously ill children that require parenteral nutrition, chemotherapy, or other medications. The jugular or subclavian veins are ordinarily used for primary access. Alternatives include the femoral veins, the intercostal veins, and transhepatic approaches. If the use of these standard sites of placement is made impossible, due, for example, to chronic thrombosis, an alternative approach has to be found. The following report presents the case of an 11-year-old girl with short-bowel syndrome and a desperate need for parenteral nutrition. Over the course of her treatment, she developed chronic thrombosis of the jugular, subclavian, and femoral veins, as well as thrombosis of the inferior vena cava. As an alternative route for central venous access, we describe a successful direct placement of a tunnelled catheter into the right atrium via a right anterolateral thoracotomy.

Lung perfusion imaging with Tc-99m MAA was performed in a patient thought to have pulmonary embolism. The dynamic flow images obtained before static lung perfusion imaging showed delayed drainage of the tracer into the right brachiocephalic vein and superior vena cava, and unusual demonstration of the right lateral thoracic and intercostal veins as collateral pathways. It was thought that coughing at the time of bolus injection of the tracer into a right antecubital vein caused an increase of intrathoracic pressure and consequently disturbed the venous return to the thorax.

Submitted by Guilherme Lemeszenski (guilherme@nead.unesp.br) on 2013-08-22T19:04:07Z No. of bitstreams: 0 Made available in DSpace on 2013-08-22T19:04:07Z (GMT). No. of bitstreams: 0 Previous issue date: 1999-01-01 Made available in DSpace on 2013-09-30T20:06:44Z (GMT). No. of bitstreams: 0 Previous issue date: 1999-01-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T15:17:03Z No. of bitstreams: 0 Made available in DSpace on 2014-05-20T15:17:03Z (GMT). No. of bitstreams: 0 Previous issue date: 1999-01-01 O comportamento da veia ázigos, sua formação e topografia foram estudados em 10 cutias (Dasyprocta aguti, rodentia) adultas (6 machos e 4 fêmeas, capturadas no estado do Piauí, Brasil). Este trabalho tem por objetivo constituir a base de outras investigações, particularmente aquelas referentes à exploração zootécnica desta espécie. O sistema de veia ázigos foi injetado com látex - Neoprene 671, e os animais foram colocados em solução aquosa de formol a 10%, e dissecados. em todas as espécies foi observado que a veia ázigos sempre chega na veia cava cranial em nível do quarto espaço intercostal. A veia ázigos recebe em (50%) dos casos as veias intercostais à direita e (50%) à esquerda. As tributárias da veia ázigos são: as veias frênicas (100%) e a veia bronco esofágica (30%). A veia hemiázigos aparece em todos os casos à esquerda e em 60% dos casos à direita. A veia ázigos comunica-se com a veia hemiázigos esquerda (90%), e com a direita (100%), com a veia cava caudal e veias intervertebrais, com igual freqüência (30%). The behaviour of the azygos vein, its formation and topography were studied in 10 cutias (Dasyprocta aguti, rodentia) adults (6 males and 4 females) captured in the State of Piauí, Brazil. This research intends to be a base for other investigations, particularly those with reference to zootechnical exploration of this species. The azygos venous system was injected with latex (Neoprene 671), then the animals were put in watery solution of formol 10%, and dissected. In all specimens it was observed that the azygos vein always arrives in the cranial vena cava on a level with fourth intercostal space. The azygos vein receives more frequently (50%), the intercostal veins on the right side and 5 (50%) on the left one. The tributaries of the azygos vein are the phrenic veins (l00%), and the broncoesophagea vein (30%). The hemiazygos vein is in all cases on the left side and in 60% of the cases on the right side. The azygos vein communicates with the left hemiazygos vein (90%), with the right one (100%), and with the vena cava caudal and intervertebral veins, with equal frequency (30%). Universidade Federal do Pauí Universidade Estadual Paulista Faculdade de Odontologia Universidade de São Paulo Faculdade de Medicina Veterinária e Zootecnia Departamento de Cirurgia Universidade Estadual Paulista Faculdade de Odontologia

Learning Objectives To facilitate widespread utilization of the parathyroid venous sampling, this pictorial assay reviews normal anatomy and its variants of considerable clinical importance. We will also present the problems and challenges they pose for the interventional radiologist. Background Parathyroid venous sampling for para-thyroid hormone (PTH) is a highly promising method for localization and diagnosis of parathyroid tumors. Sampling of small veins is the goal. The reported sensitivity of parathyroid venous sampling is 70-80%. However, patients with congenital variation in anatomy and also those with distorted anatomy due to previous surgery can sometime present significant challenge to successful completion of bilateral parathyroid venous sampling resulting in false negative test. Clinical Findings/Procedure Details Technical Details : This pictoral review presents parathyroid venous anatomy along with the details of catheterization and retrograde venography of the parathyroid venous bed wherever necessary. In the entire series of no significant complication has occurred. Normal Anatomy and Variants : The thyroid venous bed is composed of: (a) a diffusely anastomosing, valveless plexus of veins arising from and investing the thyroid gland; and (b) paired, draining superior, middle and inferior thyroid veins. - Superior thyroid veins - Middle thyroid veins - Inferior thyroid veins - most common patterns - Thymic mediastinal veins - Azygos vein and left superior intercostal veins - Few confusing veins such as anterior jugular and the vertebral veins as well as mediastinal veins. - Interesting cases Conclusion and/or Teaching Points The roentgenographic anatomy of parathyroid veins is presented. As usual with venous anatomy, variations from the preceding standard description are common. Parathyroid drainage occurs predominantly via the inferior thyroid vein. Although inferior thyroid drainage is variable, bilateral samples could be obtained in a high percentage of cases. Probably least important for parathyroid drainage, the superior thyroid was the most constant and predictable of the thyroid veins.

In the cadaver of an 86 year old man the inferior segment of the azygos vein could not be found. Furthermore, a normally developed hemiazygos vein drained the right and left intercostal veins from T 10 to T 6. This vessel finally curved towards the right to reach the superior vena cava after having drained the right superior intercostal veins. The left superior intercostal vein ended in a short vessel draining into the left brachiocephalic vein. This condition may be represented in a standard chest radiograph by the so-called "aortic nipple". Agenesis of the azygos vein, suspected because of the presence of this radiological sign, should be confirmed in the living by means of computerized tomography. This can clarify the anatomy of the mediastinal vessels precisely. Embryological pattern of the azygos system accounting for its possible defects is discussed.

Gastric varices are usually associated with a gastro-renal (G-R) shunt. However, the gastric varices described in this case report were not associated with a G-R shunt. The inflow vessel was the posterior gastric vein and the outflow vessels were the narrow inferior phrenic vein and the dilated cardio-phrenic vein. First, percutaneous transhepatic obliteration of the posterior gastric vein was performed, but the gastric varices remained patent. Then, micro-balloon catheterization of the subphrenic vein was carried out via the jugular vein, pericardial vein and cardio-phrenic vein, however, micro-balloon-occluded inferior phrenic venography followed by micro-coil embolization of the cardio-phrenic vein revealed no delineation of gastric varices resulting in no further treatment. Thereafter, as a gastro-subphrenic-intercostal vein shunt developed, a micro-balloon catheter was advanced to the gastric varices via the intercostal vein and balloon-occluded retrograde transvenous obliteration (BRTO) was performed resulting in the eradication of gastric varices. BRTO for gastric varices via the intercostal vein has not previously been documented.

Sir, Gasparetto et al. [1] present an interesting case report of a rare anomaly—asymptomatic unilateral pulmonary vein atresia that was confirmed by magnetic resonance angiography. Unlike the case reported at our institution [2], the girl had no symptoms and on follow-up after 5 years she remained asymptomatic. An asymptomatic or mildly symptomatic course of this anomaly could be explained by complexity and pliability of the bronchopulmonary circulation. Liebow [3] showed a double venous drainage in normal human lungs consisting of pulmonary and bronchial veins that intercommunicate between each other. Proximal bronchial veins drain into the azygos, hemiazygos and intercostal veins and pulmonary veins drain into the left atrium. Presumably connections between the pulmonary veins and the caval system via azygos veins are capable of expansion or proliferation in various congenital or acquired pathological conditions. Definitive diagnosis and functional parameters of this anomaly require invasive angiography, but because the girl is asymptomatic, postponement of this procedure could be justifiable. We suggest that increasing availability of cross-sectional techniques (CT, MR) with comprehensive three-dimensional visualization will be used more frequently as a first-line modality to clarify incidental findings. Therefore it is possible that this cardiovascular defect will appear to be not so infrequent.

Long-term central venous access usually is achieved by placing a catheter into the superior vena cava through the upper extremity orjugular veins [1 , 2]. Alternative percutaneous approaches to the central veins are required when the subclavian and brachiocephalic veins no longer are available due to thrombosis related to instrumentation and hypercoagulable states [1]. These alternative approaches include translumbar puncture of the infrarenal inferior vena cava (IVC), transhepatic cannulation of the hepatic veins or intrahepatic IVC, and femoral venous catheterization [1-3]. The use of intercostal veins as alternative conduits for placing central venous catheters previously has required a surgical procedure [4-7]. In this article,we describe the cannulation of an intercostal vein via the basilic vein for placement of a long-term central venous access catheten in a patient with occlusion of the subclavian veins, brachiocephalic veins, and proximal superior vena cava.

Persistence of a left superior vena cava is a congenital anomaly of considerable interest but by itself exerts no apparent adverse affect on cardiac function. It may occur as an isolated lesion but more often it is associated with many congenital cardiac anomalies. Heretofore it could only be discovered at autopsy or cadaver dissection, but angiocardiography and cardiac catheterization have made possible its recognition during life. This report is a summary of the findings of 11 cases detected by these methods at this center. Embryology In early development, the cephalic portion of the embryo is drained by bilateral symmetrical right and left anterior cardinal veins. These join the posterior cardinal veins near the heart and form the right and left ducts of Cuvier which enter the sinus venosus (Figure 1A). During the eighth week of fetal life, an oblique communication forms between the anterior cardinal veins and shunts blood from the left yein to the right. This vessel becomes the left innominate vein. The development of the left innominate vein is followed by atrophy of the left anterior cardinal vein. It normally persists as the first left intercostal vein. The left duct of Cuvier persists as the oblique vein of the left atrium which enters the coronary sinus. The latter structure is derived from the left half of the sinus venosus. The right duct of Cuvier normally becomes the superior vena cava (Figure 1B). The fully developed superior vena caval system is demonstrated in Figure 2. If the left innominate vein fails to develop, the left anterior cardinal vein persists and continues to drain the left brachiocephalic veins. In this situation it becomes the left superior vena cava. Since the left duct of Cuvier empties into the left half of the sinus venosus which ultimately becomes the coronary sinus, a persistent left superior vena cava drains into this structure (Figure lB).’-3

A widened mediastinum was found on chest radiography following blunt chest trauma. Aortography alone could not adequately determine the etiology of the radiographic findings; on computed tomography (CT) benign mediastinal widening was confirmed owing to accessory hemiazygous continuation of a left inferior vena cava (IVC), with communication to the left brachiocephalic vein through an enlarged left superior (highest) intercostal vein. This unusual anatomic variant and its radiographic findings are reviewed, as well as the complementary role of CT in the evaluation of the traumatized thoracic aorta and mediastinum.

A retrospective study of 56 MRT chest examinations showed the left intercostal vein in its horizontal trajectory in 3 patients with left mediastinal masses compressing the superior vena cava. In 2 patients the posterior trajectory of the horizontal segment was clearly visualised. In the third case the anterior part, namely the insertion of the left superior intercostal vein into the left brachiocephalic trunk, was demonstrated.

The right superior intercostal vein is visualised on CT examination as a circular opacity laterally at the right aspect of the vertebral body at the T4-T5 level. In venographic examination the RSIV appears to be formed by the confluence of the venous channels, the right second, third and fourth intercostal veins. In superior vena cava obstruction the RSIV is an important collateral pathway: the flow through the vein depends on the site of the obstruction, anterograde if the obstruction is superior or parallel to the level of the vena azygos, and retrograde if the obstruction is below the vena azygos.

The azygos system (Fig. 282) consists of 3 veins which form longitudinal collecting trunks into which the intercostal veins drain: the azygos (vena azygos major), the hemiazygos (vena azygos minor inferior) and the accessory hemiazygos (vena azygos minor superior). The azygos is located on the right side, and the hemiazygos and the accessory hemiazygos on the left. The right and the left ascending lumbar veins constitute the most caudal portion of the system and drain into the azygos and the hemiazygos, respectively. These veins, because they link together the superior and the inferior venae cavae, constitute important anastomosing channels.

In fifty-three cats the arterial blood supply to the diaphragm was studied and some observations made on the venous drainage. The arteries arise from the 8th to 13th intercostal arteries, the internal mammary arteries and from branches of the abdominal aorta. Rarely there are direct branches from both the thoracic and the abdominal aorta. There are considerable variations in the pattern of supply. The veins drain into tributaries of the intercostal veins, the internal mammary veins and into the inferior vena cava.

In a dissection performed in our department, we observed multiple variations of the azygos venous system. The hemiazygos vein was absent. The posterior 8th, 9th, and 10th intercostal veins united and their common trunk crossed the vertebral column obliquely lying anterior to the aorta and posterior to the esophagus and opening into the azygos vein at the level of T7-T8 vertebrae. The 7th left posterior intercostal vein also crossed the column anteriorly and joined the common trunk. The present report identifies the variable positions and courses of the veins related to the azygos system. It is important to keep in mind that different courses of the azygos system do exist, so that extra caution is required during surgery of the mediastinum and also in appropriately interpreting the radiographs.

Background The azygos venous system consists of the azygos vein on the right side and the hemiazygos and accessory hemiazygos on the left side. The azygos vein runs through the abdominal cavity along the right side of the vertebral bodies, in a cranial direction, passes through the diaphragm and reaches the mediastinum, where it forms the arch of the azygos which flows into the superior vena cava. Along its course, the azygos vein communicates with the intercostal veins on the right, the hemiazygos vein that collects blood from the left lower intercostal veins, and accessory hemiazygos vein that drains into the left upper intercostal veins. The last two, at the level of the seventh thoracic vertebra, unite and end in the azygos vein. The accessory hemiazygos vein is normally included in the length between T4 and T8. The embryological origin of the accessory hemiazygos vein is the result of an expansion in the direction of the cranial hemiazygos vein, which comes from the left upper sovracardinale vein (Dudiak et al. in Semin Roentgenol 24(1):47–55, 1989; Radiographics 11(2):233–246, 1991; Webb et al. in Am J Roentgenol 139(1):157–161, 1982). Findings This case report describes a rare variant of azygos vein system identified in prenatal diagnosis and confirmed by postnatal ultrasonography. Conclusions The observation of the patient has excluded hemodynamic alterations associated with vascular anomaly.