Brain anatomy, cerebral blood flow, and connectivity in the transition from PVS to MCS

We report a 15 year-old girl with sickle cell disease, who developed important cognitive impairment due to multiple strokes, and who had been diagnosed with PVS. Nonetheless, when she was later admitted to our Institute, according to the presence of inconsistent but clearly demonstrable behavioral evidence of consciousness awareness, we changed our diagnosis to MCS.

This patient was studied by T1 MRI images, co-registration of fractional anisotropy (FA), and SPECT with MRI.

Brain structures were mainly preserved in posterior areas of both cerebral hemispheres, although small tissue islands were present in both frontal lobes, mainly preserved in the right one. SPECT showed CBF preservation in posterior brain regions and in the cerebellum, and in those frontal small islands of tissue lateralized to the right frontal lobe; meanwhile FA showed preservation of anatomical connectivity among posterior and frontal brain regions. These remaining cortical regions are also connected with the thalami.

These results showing connectivity among posterior and frontal cortical and probably with other subcortical regions, and CBF preservation in these areas, might explain the recovery of minimum awareness despite huge anatomical brain lesions.