| Chest X-ray (PA and Lateral) | |
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The chest X-ray (PA and lateral) findings include a right pleural effusion. After left arm injection, the perfusion scan shows extra pulmonary activity in the kidneys, the left lobe of the liver, and faintly in the neck region. There is a separation between the liver and lung activity compatible with the right pleural effusion on chest X-ray. Additional images were obtained of the head and anterior abdomen. Images of the head show activity in the brain (arrow) indicating right-to-left shunting. Images of the abdomen show activity in the left lobe of the liver (outline) due to known superior and inferior vena caval obstruction from idiopathic mediastinal fibrosis. Left lobe visualization, due to collaterals via the umbilical vein, is particularly prominent due to long standing high flow shunting.
A CT without contrast obtained at the time of the index presentation shows decreased attenuation in the left lobe (arrows) corresponding to the region of increased activity on lung scintigraphy. Decreased attenuation is likely related to the marked increased blood flow through the liver.
Pulmonary perfusion is otherwise uniform. Absence of pulmonary embolism was confirmed by a negative transhepatic pulmonary angiogram.
The patient returned 5 and 1/2 months later and had a repeat lung scintigraphy was performed.
| Chest X-ray (PA and Lateral) | |
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| Lung Scintigraphy | |
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The chest X-ray shows a left pleural effusion. (The effusion was on the right side on the previous study.) After left arm injection, the lung scan again shows findings of a right-to-left shunt.
At the time of initial presentation first pass studies were performed from the right and left arms.
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Images obtained after injection from the right arm show multiple collateral veins without visualization of the superior vena cava compatible with the know superior vena cava obstruction. There is prompt appearance of the left ventricle and abdominal aorta (arrows) without visualization of the right heart. These findings are compatible with an echocardiographic study which showed appearance of bubbles in the left heart without transit through the right heart.
Images obtained after injection from the left arm show collateral vein to the left of midline (arrow) followed by a collection of collaterals underlying the same region. This region corresponds to the area of increase activity in the left upper lobe seen on both lung scans. A similar venous-to-pulmonary collateral has been reported previously (Gale B, Chen C, Chun KJ, Lan J, Synamon J, Freeman LM: Systemic to pulmonary venous shunting in superior vena cava obstruction: Unusual myocardial and thyroid visualization. Clin Nucl Med 1990; 15:246-250). The arrowhead shows prominent collaterals overlying the region of the liver. Later in the study there is increased activity over the region of the right lobe of the liver. A CT with contrast injected via the right arm obtained two years prior to the index presentation shows multiple collaterals along the surface of the liver (arrows) and in the abdominal wall (arrow heads).
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