Systemic-to-pulmonary Venous Shunt in Superior Vena Cava Syndromes revealed on Multi-detector Spiral CT
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Objective To observe enhancement of CT imagining of systemic-to-pulmonary venous shunts in patients with superior vena cava syndromes(SVCS).Also to analyze the notable and reoccurring characteristics of systemic-to-pulmonary venous shunts.Methods Divide 33 SVCS patients into three groups according to the position of blocking: position of blocking above the azygos vein,position of blocking below the azygos vein,position of blocking above and below the azygos vein.Also divide 33 SVCS patients into two groups according to pleural thickening or not.Results There are 7 patients in the group of blocking above the arch of azygos vein,9 patients in the group of blocking below the arch of azygos vein,and 17 patients in the group of blocking above and below the arch of azygos vein.There are 10 patients in the group of pleural thickening and 23 patients in the group of pleural not thickening.Conclusion Systemic-to-pulmonary venous shunts in superior vena cava obstruction commonly shows in two forms of on computer tomography.Shunts occurrence are closely related to position of blocking in superior vena cave and pleural thickening or not,it frequently occurs in the group of blocking above and below the arch of azygos vein in the group of pleural thickening.Keywords:
Azygos vein
Pleural thickening
Blocking (statistics)
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An unusual case of systemic vein to pulmonary vein communication in superior vena cava obstruction is reported. This was a right-to-left shunt, demonstrated by spiral CT and aided by three-dimensional reconstruction. The pulmonary venous shunts were mainly seen in fibro-atelectatic lung where prominent bridging veins were concentrated.
Right-to-left shunt
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Azygos vein
Behcet disease
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Azygos vein
Venous return curve
Pulmonary vein stenosis
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The venous system of man, in accord with conventional anatomic description, is divided into two main groups: the pulmonary veins and the systemic veins. With the exception of the cardiac veins, the systemic venous drainage returns to the heart through two great vessels, the superior and the inferior vena cava. From the cranial cavity and the upper extremities the blood converges on the superior vena cava, and from the abdominal viscera and lower extremities on the inferior vena cava. Obstruction of either of these trunks is not incompatible with life in man (5, 36, 39). The development of a large by-pass mechanism, effectively establishing communication between the two vast caval drainage areas, is accomplished by collateral vessels, of which the vertebral veins and the azygos system form an important component (34, 37, 39, 40). In the dog, both venae cavae may be occluded for thirty minutes, with survival, if the azygos vein is patent (3). This is accompanied by a fivefold increase in azygos blood flow. How this is possible becomes apparent after consideration of the intercommunications of the vertebral veins (4, 37). At the base of the brain, they anastomose extensively with the venous trunks of the cranium; in the neck, with the deep cervical veins; in the thorax and abdomen, with the intercostal and lumbar veins; in the pelvis, with the large venous plexuses anterior to the sacrum. In turn, the sacral and lumbar veins communicate directly with the inferior vena caval system, the lumbar and intercostal veins with the azygos system, and the azygos system with the superior vena cava and its branches (26). In the early 1940's, Batson revived interest in the vertebral system of veins by demonstrating that a thin opaque medium injected into the dorsal vein of the penis of a cadaver would spread into the sacral canal, fill the veins in the wings of the bony pelvis, and finally move up the vertebral system as far as the cranial cavity. The mode of spread was similar to that of carcinoma of the prostate, and Batson suggested that in the great venous lakes formed by these plexuses, tumor emboli might well spread from origin to final site of deposition. He also showed that the vertebral veins filled, following injection in a live monkey, if the inferior vena cava were compressed (6–8). Shortly after Batson described the anatomy of the vertebral veins and expounded his theory of their role in metastases, Harris went to great lengths to prove that Batson's ideas were neither new nor original (24). As a matter of fact, the vertebral venous system was by no means unknown to anatomists prior to Batson's time, although Franklin in his Monograph on Veins, written in 1937, did not even mention the vertebral plexuses (20). Willis in 1664 (48) and Winslow in 1732 (49) characterized the structure of the spinal veins. Bock in 1823 described the rich plexuses within the bony canal, the posterior venous plexus, and the azygos system (9).
Azygos vein
Venous return curve
Venae cavae
Thorax (insect anatomy)
Lumbar arteries
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Azygos vein
Venous return curve
Diaphragm (acoustics)
Left Pulmonary Vein
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Azygos vein
Venous return curve
Diaphragm (acoustics)
Left Pulmonary Vein
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We report a case of a complicated vascular access secondary to systemic venous defects which have not been previously reported. Further evaluation revealed congenital absence of superior vena cava with two brachiocephalic veins draining separately. He also had absence of the hepatic segment of the inferior vena cava with azygos continuation. The patient did not have congenital anomalies of the remaining thoracoabdominal vasculature and viscera.
Azygos vein
Venous return curve
Vena cava
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Venous return curve
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A 45-year-old woman with a history of recurrent pulmonary embolism was admitted to the emergency clinic with dyspnea, wheezing and tachypnea. Partial deep vein thrombosis of the popliteal vein was seen on Doppler sonography. On the contrast-enhanced thorax computed tomography (CT) scan, a clot was detected in the right main pulmonary artery and its major descending branch. Moreover, the azygos vein was prominently dilated. Abdominal multi-slice computed tomography (MSCT) scan revealed absence of the hepatic segment of the inferior vena cava (IVC) with continuation of the IVC as a dilated right-sided azygos vein. The hepatic veins were draining directly into the right atrium. Thus, we discuss herein this rare anatomic variant presented with recurrent pulmonary embolism, together with the findings on MSCT.
Azygos vein
Tachypnea
Popliteal vein
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