Magnetic resonance imaging of the postpneumonectomy chest: normal and abnormal findings

To determine the normal findings at magnetic resonance imaging (MRI) of the postpneumonectomy space (PPS), and to evaluate the utility of MRI in detection of recurrent tumor in the postpneumonectomy chest, 32 MRI scans were performed in 31 patients at varying time intervals after pneumonectomy. Eleven patients also had 12 computed tomography (CT) scans performed at the same time to evaluate possible tumor recurrence. Of the 32 scans, 5 demonstrated complete obliteration of the fluid containing PPS, and 4 showed gas in the PPS; the remainder (n = 23) demonstrated persistence of fluid-filled spaces of varying size. The presence of a fibrotic rim of tissue was constant. In 11 patients with clinically suspected tumor recurrences, both CT and MRI were obtained: the two modalities performed with similar accuracy in diagnosing tumor recurrence at 16 sites; CT detected opposite-lung metastatic nodules not seen on MRI in one patient, and a rib metastasis described as "indeterminate" on MRI in a second patient. MRI detected a focus of recurrence in the PPS that was indeterminate on CT. There is considerable variability in the amount of fluid seen in the PPS on MRI. CT remains the procedure of choice for routine follow-up or in suspected tumor recurrence in the postpneumonectomy patient; MRI can be helpful if the CT scan is nondiagnostic or equivocal.