Table 4.

Common differential diagnoses of cytotoxic lesions of the corpus callosum (CLOCC) including their magnetic resonance imaging (MRI) characteristics

	T1w	T2w-FLAIR	T1w Gd	SWI	DWI	Comments
CLOCC	Hypointense	Hyperintense	No enhancement	No SWI artifacts	Diffusion restriction	Mostly reversible within a few weeks
Lymphoma, glioblastoma, metastases	Usually hypointense	Usually hyperintense	Gd enhancement in the majority of cases	Potential intratumoral susceptibility signals or hermorrhagic components	Diffusion restriction depends on the tumor cellularity	Often in line with a mass effect
Ischemic stroke	Hypointense	Demarcated ischemic tissue hyperintense	Acute: No enhancement Subacute: Gd enhancement Chronic: No enhancement	Usually no SWI artifacts, however hemorrhagic transformation possible	Diffusion restriction in acute and subacute cases	T2w-FLAIR hyperintensity not reversible
MS, ADEM	Hypointense	Hyperintense	Gd enhancement in active lesions	No SWI artifacts	Diffusion restriction might be visible in active lesions	Additional white matter lesions
Diffuse axonal injury (DAI) of the corpus callosum	Hypointense	Hyperintense	No enhancement	Blood products visible in SWI	Diffusion restriction might be visible in acute lesions	Associated with traumatic brain injury and indicates a poor prognosis
Marchiafava-Bignami disease	Hypointense	Usually hyperintense	No enhancement	No SWI artifacts	Diffusion restriction	Usually affects the central layers of the corpus callosum. Lesions resolve after successful therapy

Abbreviations: ADEM acute demyelinating encephalomyelitis, DWI diffusion-weighted imaging, FLAIR fluid-attenuated inversion recovery, Gd gadolinium, MS multiple sclerosis, SWI susceptibility-weighted imaging