Imaging Pearls ❯ Vascular ❯ SVC
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- SVCS is a combination of signs and symptoms that result from the compression or occlusion of the superior vena cava, associated with a significant morbidity and mortality. While thoracic malignancy is the most common cause of SVCS accounting for more than 60% of the cases, benign causes are on the rise with the increasing use of central venous catheters and indwelling cardiac devices .Benign SVCS usually has a more insidious course compared to malignant causes, as there is time for the development of adequate collaterals to bypass the central venous occlusion.
Superior vena cava syndrome with the hepatic ‘hot spot’ sign.
Koratala, A., Bhatti, V.
Intern Emerg Med 13, 293–294 (2018). - A CT scan of the chest with contrast excluded acute pulmonary embolism, but showed extensive chest wall venous collaterals with near-complete occlusion of the superior vena cava. In addition, it demonstrated the “focal hepatic hot spot sign,” which is an enhanced area in the segment IV or quadrate lobe of the liver, which results from the communication between superficial epigastric veins and left portal vein in cases of superior vena cava obstruction
Superior vena cava syndrome with the hepatic ‘hot spot’ sign.
Koratala, A., Bhatti, V.
Intern Emerg Med 13, 293–294 (2018). - OBJECTIVE. The purpose of this article is to review the CT findings associated with superior vena cava obstruction and to illustrate collateral venous pathways bypassing the ob-struction as shown on MDCT.
CONCLUSION. Multiple collateral venous pathways can form to bypass an obstruction of the superior vena cava. With its ability to acquire near isotropic data, MDCT allows high-quality reformations and thus exquisitely displays these venous collaterals and has the potential to aid in planning therapy to bypass the obstruction.
Superior Vena Cava Obstruction Evaluation With MDCT
Sheila Sheth, Mark D. Ebert, and Elliot K. Fishman
American Journal of Roentgenology 2010 194:4, W336-W346 - “Obstruction of the superior vena cava re-sults in impaired venous drainage of the head and neck and upper extremities. Clinical manifestations include facial and neck swelling, distended neck veins, headache due to cerebral edema, dyspnea, and, in severe cases, stridor and altered mental status. Cor-relation of imaging studies with clinical find-ings suggests that the severity of symptoms depends on the level of obstruction (above or below the level of the azygos arch) and the development of rich collateral network. In fact, CT can detect subclinical superior vena cava obstruction in patients who are relatively asymptomatic.”
Superior Vena Cava Obstruction Evaluation With MDCT
Sheila Sheth, Mark D. Ebert, and Elliot K. Fishman
American Journal of Roentgenology 2010 194:4, W336-W346 - “The radiologist should be familiar with findings on abdominal CT that suggest the presence of a superior vena cava obstruc-tion. In addition to enhancing round or tortu-ous vascular channels in the abdominal wall, perfusion abnormalities in the liv-er and the so-called “hot spot” initially de-scribed on nuclear medicine both result from communication between superficial epigas-tric veins and left portal vein. On CT, there is intense opacification of the anterior quadrate lobe. The area of enhancement is characteristic in its position as well as its shape and should not be mistaken for a hypervascular mass.”
Superior Vena Cava Obstruction Evaluation With MDCT
Sheila Sheth, Mark D. Ebert, Elliot K. Fishman
AJR 2010; 19 4:336–346 - “Fibrosing mediastinitis is a rare histologically benign disorder caused by proliferation of collagen tissue and fibrosis in the mediastinum. It may be idiopathic, caused by an abnormal immunologic response to Histoplasma capsulatum infection or to tuberculosis, or it may be related to retroperitoneal fibrosis, particularly in its diffuse form. Radiation-induced fibro-sis is another potential cause of superior vena cava obstruction.”
Superior Vena Cava Obstruction Evaluation With MDCT
Sheila Sheth, Mark D. Ebert, Elliot K. Fishman
AJR 2010; 19 4:336–346 - “The incidence of catheter-induced supe-rior vena cava obstruction is rapidly increasing. Large central venous catheters, such as dialysis catheters, Hickman catheters, and parenter-al nutrition catheters, have all been implicated in superior vena cava obstruction. Transvenous permanent cardiac pacemaker implantation is another risk factor, particularly after an atrio-ventricular node ablation procedure.”
Superior Vena Cava Obstruction Evaluation With MDCT
Sheila Sheth, Mark D. Ebert, Elliot K. Fishman
AJR 2010; 19 4:336–346 - “The azygos and hemiazygos veins can divert blood away from the superior vena cava. If the level of superior vena cava obstruction is above the azygos arch, antegrade flow from the azygos to the right atrium is seen, with abrupt transition between a densely opacified azygos above the arch and an unopacified inferior azygos vein. If the obstruction is below the arch, the entire azygos and hemiazygos veins are bright-ly opacified as the blood flows in a retro-grade fashion toward the inferior vena cava .”
Superior Vena Cava Obstruction Evaluation With MDCT
Sheila Sheth, Mark D. Ebert, Elliot K. Fishman
AJR 2010; 19 4:336–346
- Collateral pathways are commonly opacified in SVC Syndrome
- Azygous and hemiazygous system
- Paravertebral vessels
- Mediastinal veins as collaterals (as in this case)
- Anterior intercostal veins
- Internal mammary veins
- "Venous collateral pathways caused by the thoracic central venous obstruction from a complex network of venous drainage and can be simplified by application of 3-dimensional techniques that merge the tortuous vessels."
Collateral Pathways in Thoracic Central Venous Obstruction: three Dimensional Display Using Direct Spiral Computed Tomography Venography
Kim HC et al J Comput Assist Tomogr 2004; 28:24-33