Recovery of an injured corticoreticular pathway via transcallosal fibers in a patient with intracerebral hemorrhage

Several studies have reported on injury of the corticoreticular pathway (CRP), however, little is known about the mechanism for recovery of an injured CRP. We report on a patient with intracerebral hemorrhage (ICH) who showed recovery of an injured CRP via transcallosal fibers, which was demonstrated by diffusion tensor tractography (DTT).

A 67-year-old man presented with complete paralysis (Medical Research Council: 0/5) of the left extremities at the onset of a right putaminal hemorrhage. At six weeks after onset, he presented with more severe weakness of proximal joint muscles than distal joint muscles (right shoulder abductor; 2⁻, finger extensor; 3⁺, hip flexor; 2⁺, ankle dorsiflexor; 3). Although his right hemiplegia had recovered well, he consistently showed more severe proximal weakness (right shoulder abductor; 3, finger extensor; 4, hip flexor; 3⁺, ankle dorsiflexor; 4) until 16 weeks after onset. On both six- and 16-week DTTs, in the left (affected) hemisphere, the CRP showed severe narrowing with discontinuation of the anterior fibers at the corona radiata on six-week DTT, however, the discontinued anterior fibers of the CRP were connected to the right cerebral cortex via transcallosal fibers on 16-week DTT.

We demonstrated recovery of an injured CRP via transcallosal fibers in a patient with ICH. We believe that this might be a mechanism for recovery of an injured CRP.