A 67-year-old woman with multiple myeloma and recently treated left upper pneumonia was admitted to the hospital for acute-onset shortness of breath. Chest radiography showed a left upper lobe infiltrate. CT angiography revealed right-sided pulmonary embolus. IV heparin was started through a new right subclavian central venous catheter. The patient was then transferred to the Methodist Hospital for further care. Physical examination revealed BP of 106/60 mm Hg, pulse of 110 beats/min, respiratory rate of 24 breaths/min, and pulse oximetry showed 98% saturation on 4 L/min O2 by nasal cannula. The patient had a generalized tonic-clonic seizure on the second day of hospital admission, and MRI of the brain showed a small infarct in the right posterior temporal lobe. Serum electrolytes were within normal range, and workup for hyperviscosity syndrome and meningitis was not pursued as the patient had rapid resolution of symptoms. A lung perfusion scan using IV 99m Tc macroaggregated albumin (MAA) was performed, and images of the brain and kidney were obtained to look for a possible shunt. Perfusion scan showed marked tracer uptake in the right upper extremity, right cerebral hemisphere, and right cerebellum, but absence of perfusion to a majority of the left side of the brain, left face, left side of the neck (Fig 1), and left upper extremity (Fig 2).