Female, 58 years old, with small cell lung cancer and brain metastases status post whole brain radiation in 2014. Two adjacent cystic masses in the left parietal lobe have decreased substantially in size since the prior examination. The degree of surrounding parenchymal T2 hyperintensity is also significantly improved.One of the lesions contained blood fluid levels on the prior examination, and this lesion now shows evidence of peripheral hemosiderin staining. A round focus of FLAIR hyperintensity and apparent restricted diffusion is seen central to this region of hemosiderin staining. On T1 weighted images, there appears to be some intermediate signal debris adherent within this region. Otherwise, the remainder of the cystic spaces are largely FLAIR hypointense.Scattered small foci of white matter T2 hyperintensity seen elsewhere within the brain are not significantly changed. No evidence of new parenchymal edema or mass effect is detected. The ventricular system is normal in size and morphology.
1. Significant interval decrease in the size of two adjacent cystic masses in the left parietal lobe. The degree of surrounding parenchymal edema has also improved.2. One of the cystic lesions contains evidence of chronic blood product. FLAIR hyperintensity and apparent restricted diffusion along the inferior aspect of this lesion seem to correlate with a small quantity of adherent debris. The signal characteristics of this debris may reflect blood product or very viscous material. Infectious material, however, can present similarly, and as such, correlation with clinical and laboratory findings is recommended.3. Without the benefit of IV contrast, no definite evidence of any new parenchymal metastases is seen.