Multislice computed tomography technology has enabled sophisticated insights into the evaluation of collateral venous pathways in the thorax. A small but well-established body of literature has described the multiple venous pathways in patients with central venous obstruction. In unusual circumstances, however, physiologically maladaptive pathways have been described involving systemic to pulmonary venous shunts. This paper describes 21 patients with systemic to pulmonary venous shunts having a wide spectrum of etiologies. Clinical presentations typically include cardiopulmonary symptomatology and paradoxical emboli. Ultrafast magnetic resonance and multislice computed tomography established the diagnosis of this uncommon but important entity.