Superior Vena Cava Syndrome Induced Collateral Circulation on 99mTc–Macroaggregated Albumin Lung Perfusion Scintigraphy

Abstract

Perfusion lung scintigraphy using SPECT/CT is one mainstay in diagnosing pulmonary embolism. Although typically almost all tracer will be accumulated in the lung capillaries, occasionally abnormal uptake can be detected. As superior vena cava syndrome leads to aberrant blood flow, tracer injected to an arm vein might partly circumvent the pulmonary capillary bed and accumulate in well-perfused anatomical structures. In this case, next to the commonly described liver enhancement, more prominent pseudo-uptake of various thoracic vertebrae was observable. However, a time-related FDG PET/CT demonstrated only the hepatic pseudo-uptake. Taken together, careful assessment of superior vena cava syndrome patient studies is highly recommended.

A False-Positive Bone Oligometastatic Prostate Cancer in 18F-Choline PET/CT

“…A single publication reported this false-positive with 18 F-FDG PET/CT. A few similar cases have been reported with 99m Tc-MDP bone scintigraphy and with 99m Tc–macroaggregated albumin lung perfusion scintigraphy 5–8 . These false-positives are explained by an aberrant blood flow related to collateral venous networks, including sternal and thoracic vertebra venous plexus.…”

“…A few similar cases have been reported with 99m Tc-MDP bone scintigraphy and with 99m Tc-macroaggregated albumin lung perfusion scintigraphy. [5][6][7][8] These false-positives are explained by an aberrant blood flow related to collateral venous networks, including sternal and thoracic vertebra venous plexus. Thus, the radiopharmaceutical injected in an upper limb could circumvent the usual subclavicular venous path and instead go through the better perfused venous bed of dilated internal thoracic vertebral and sternal venous plexus.…”

False-Positive Bone Lesion With Different PET/CT Tracers

“…Several false-positive vertebral and sternal lesions secondary to collateral circulation on acute or chronic thrombosis have been reported, using different tracers. [3][4][5][6] Neither false-positive scapular topography nor collateral circulation without thrombosis has been described yet. Any collateral venous network seems to be a source of false-positive bone uptake, whatever the cause: thrombosis, stenosis, or mass.…”

False-Positive Bone Pitfall Lesion and Collateral Circulation

“…Numerous cases of false-positive bone lesions related to thrombosis have been reported with different tracers. [1][2][3][4][5] Beyond the phenomenon of thrombosis, the more general process of collateral circulation can give rise to false-positives, whether due to thrombosis, stenosis, or mass. The obstacle will give rise to an aberrant collateral venous network to return to the heart.…”

“…On the other hand, the sternal focus had clearly progressed, consistent with the appearance of a lytic lesion ( A and D , fusion axial PET/CT and axial CT, white arrows). Numerous cases of false-positive bone lesions related to thrombosis have been reported with different tracers 1–5 . Beyond the phenomenon of thrombosis, the more general process of collateral circulation can give rise to false-positives, whether due to thrombosis, stenosis, or mass.…”