History: 38 yo male with onset of severe headaches and left hand numbness.
Solution: Brain abscesses
The MRI identifies multiple ring enhancing lesions in the brain. We are all familiar with the differential diagnosis for this finding, i.e. MAGICAL DR, Metastasis, Abscess, Glioblastoma multiforme, Infarct, Contusion, AIDS toxoplasmosis, Lymphoma, Demyelinating disease, Radiation necrosis/Resolving hematoma. We can eliminate several of these based upon the multiplicity and history. No history of trauma (resolving hematoma and contusion). No history of radiation (not radiation necrosis). Numerous lesions (not GBM). Young and no vascular disease (not infarct). This leaves us with mets, abscesses, toxo, and lymphoma. Although I don\'t specifically tell you this, he does not have a history of AIDS, which makes both toxo and lymphoma much less likely. He doesn\'t have a given history of malignancy, so in a 38 yo male, metastases are unlikely, which leaves you with abscesses. Combine that with the fact that there is restricted diffusion and you have the diagnosis. The intense signal on DWI appears to be related to the cellularity and viscosity of the contents within the abscess cavity and helps to differentiate these from tumors, which don\'t tend to have restricted diffusion.
Most commonly, infectious agents gain access to the CNS by spread from a contiguous focus of infection, including: otitis media, mastoiditis, infection of the paranasal sinuses, or dental infection. Infection can also spread hematogenously from an distant site, from thrombophlebitis, or other sources. Diabetics and immunosuppressed patients are at highest risk, but anyone can develop brain abscesses.
Brain abscesses develop in three stages, 1) vascular congestion with petechial hemorrhage and edema, 2) cerebral softening and necrosis and 3) liquefaction, cavitation, and capsule formation.
Remember that restricted diffusion does not equal infarct!
The MRI identifies multiple ring enhancing lesions in the brain. We are all familiar with the differential diagnosis for this finding, i.e. MAGICAL DR, Metastasis, Abscess, Glioblastoma multiforme, Infarct, Contusion, AIDS toxoplasmosis, Lymphoma, Demyelinating disease, Radiation necrosis/Resolving hematoma. We can eliminate several of these based upon the multiplicity and history. No history of trauma (resolving hematoma and contusion). No history of radiation (not radiation necrosis). Numerous lesions (not GBM). Young and no vascular disease (not infarct). This leaves us with mets, abscesses, toxo, and lymphoma. Although I don\'t specifically tell you this, he does not have a history of AIDS, which makes both toxo and lymphoma much less likely. He doesn\'t have a given history of malignancy, so in a 38 yo male, metastases are unlikely, which leaves you with abscesses. Combine that with the fact that there is restricted diffusion and you have the diagnosis. The intense signal on DWI appears to be related to the cellularity and viscosity of the contents within the abscess cavity and helps to differentiate these from tumors, which don\'t tend to have restricted diffusion.
Most commonly, infectious agents gain access to the CNS by spread from a contiguous focus of infection, including: otitis media, mastoiditis, infection of the paranasal sinuses, or dental infection. Infection can also spread hematogenously from an distant site, from thrombophlebitis, or other sources. Diabetics and immunosuppressed patients are at highest risk, but anyone can develop brain abscesses.
Brain abscesses develop in three stages, 1) vascular congestion with petechial hemorrhage and edema, 2) cerebral softening and necrosis and 3) liquefaction, cavitation, and capsule formation.
Remember that restricted diffusion does not equal infarct!
MR Images
