Case Author(s): J. Philip Moyers, MD, and Barry A. Siegel, MD , 1/17/96 . Rating: #D3, #Q3

Diagnosis: Occlusion of the superior vena cava

Brief history:

The patient presented with hematochezia on the evening before this study. The patient now has persistent melena. Please evaluate for source of bleeding.


Anterior summed images from GI bleeding study

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Full history/Diagnosis is available below

Diagnosis: Occlusion of the superior vena cava

Full history:

This patient has a history of lymphoma and known superior vena caval obstruction secondary to thrombosis caused by indwelling central venous access catheters. The patient does not currently have superior vena cava (SVC) syndrome.


20.6 mCi Tc-99m in vitro labeled red blood cells


The anterior radionuclide angiogram demonstrates abnormal activity over the left flank extending into the left abdominal region and finally to the left pelvis, then traversing in a more caudad direction prior to visualization of the aorta and iliac artery. This study was done after a left arm injection of the radiopharmaceutical. Delayed images demonstrate multiple irregular linear collections of activity along the abdominal wall consistent with dilated anterior abdominal wall collateral venous structures.. These findings are consistent with superior vena caval obstruction with abdominal wall collateral vasculature. No abnormal focus of labeled red blood cell extravasation is demonstrated to suggest gastrointestinal bleeding, however.


Superior vena cava syndrome, which is caused by obstruction of the SVC with development of collateral pathways, is characterized by head and neck edema (70%), enlarged cutaneous venous collaterals, syncope, headache, dizziness, proptosis, excessive tearing, dyspnea, chest pain, cyanosis, and hematemesis (11%). The causes of superior vena cava obstruction may be divided into malignant (85%) and benign (15%) etiologies. Bronchogenic carcinoma and lymphoma make up the majority of malignant causes. Benign diseases causing SVC obstruction include granulomatous mediastinitis (tuberculosis, histoplasmosis, sarcoidosis, etc.), substernal goiter, aortic aneurysm, constrictive pericarditis, and foreign bodies (central venous catheters/pacer wires).

Radiographic findings include superior mediastinal widening, dilated cervical and superficial veins, SVC thrombus, and encasement or compression or occlusion of the SVC. The common collaterals pathways include the esophageal venous plexus (downhill varices), azygous and hemiazygous veins, accessory hemiazygous and superior intercostal veins (aortic nipple), lateral thoracic veins, parumbilical veins, and vertebral veins.

In SVC obstruction, Tc-99m sulfur colloid scintigraphy (not performed here) often displays a characteristic pattern. The intravenously injected radiopharmaceutical passes through collateral thoracic veins to abdominal wall collaterals and thence to the paraumbilical veins, if patent. The paraumbilical veins usually drain into a branch of the left portal vein supplying the quadrate lobe of the liver. Under these circumstances, liver-spleen scintigraphy shows a focal area of increased Tc-99m sulfur colloid uptake in this region of the liver.


The patient was taken to the angiography suite where recannulization of an occluded right-sided subclavian vein was performed. A superior vena cavogram at that point demonstrated extensive SVC thrombus extending into the right atrium. Because of this, no superior vena caval stent was placed.

ACR Codes and Keywords:

References and General Discussion of Gastrointestinal Bleeding Scintigraphy (Anatomic field:Vascular and Lymphatic Systems, Category:Organ specific)

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Case number: gi003

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