Rapid differential diagnosis of tumefactive demyelinating lesions and brain tumors by neuroimaging

Abstract

Tumefactive demyelinating lesions (TDLs) is a special inflammatory demyelinating disease with space-occupying lesions. The problem of bilateral misdiagnosis between TDLs and brain tumor mainly lies in that neurologists, neurosurgeons and radiologists do not fully grasp the imaging characteristics of TDLs. Differential diagnosis from TDLs and brain tumor can be made according to the imaging characteristics as following:1.Comparison of T1 and T2 signals: TDLs had clear image edges of lesions on T1 and T2, while astroglioma had unclear boundaries presenting as “foggy-like”.2.Comparison of CT scan: PCNSL and astrocytoma lesions on plain CT often show hyper density, some slightly higher or equal density. TDLs lesions were low density. enhanced CT showed that TDLs lesions were non-enhanced, while PCNSL lesions significantly enhanced. Grade 3 or above can be slightly or significantly enhanced.3.Comparison of brain stem lesions: The basilar artery “embedding” sign is a glioma. TDLs had small lesions but significant symptoms,but tumors do the opposite.4.Contrast enhanced MRI: TDLs in different course showed different enhanced dynamic imaging. Ring, Broken rings, open-ring, C or inverse C shaped enhancement, “comb” sign were features of TDLs.Most of the PCNSL exhibited round enhancement. Multiple nodules and complete annular enhancement are common in astrocytoma.5.Comparison of ASL or PWI in MRI: blood supply of astroglioma can be presented as hyperperfusion; TDLs showed no hyper perfusion. Most of the PCNSL were of equal or slightly higher perfusion.6.SWI comparison: no bleeding on SWI in TDLs; High grade astrocytoma often see hemorrhagic signals in SWI; Less PCNSL bleeding