A bone scan and a head MRI were negative. A lung scan showed a ventilation perfusion mismatch in the right lower lobe, and the patient was anticoagulated. Ventilation scan in the posterior projection was performed with Xe-133 gass followed by an 8 view perfusion scan. Axial T1, sagittal T1 and coronal 3D FISP images were obtained post-gadolinium injection. Coincidence imaging was performed 1.5 hours after intravenous injection of F-18 labelled FDG in the fasting state.
Arrows show the area of mismatch.
Arrows on the axial images show the mass. Arrows on the coronal images show the mass. Not shown were peripheral embolic disease, and scattered 1 cm lymph nodes. The differential diagnosis also includes bronchogenic carcinoma, lymphoma, metastatic disease, sarcoma, aneurysm, sarcoid, and fungal or granulomatous infection. However, the hypermetabolic nature of the right hilar mass makes pulmonary embolization unlikely.