FIG 4. A, Proton MR spectra obtained from the splenium of two patients with head injury. The arrow identifies the methyl resonance of NAA, which is at 2.02 parts per million. The top spectrum was recorded in a patient with an initial GCS of 14 and a GOS of 5 and an NAA/Cr of 1.52. The bottom spectrum shows a lowering in the NAA peak that results in a decreased NAA/Cr ratio of 1.16 in a patient with a GCS of 4 and GOS of 2.

B, T2-weighted MR image (2700/85/1) from patient in top spectrum in A.

C, T2-weighted MR image (2700/80/1) from patient in bottom spectrum in A shows postoperative changes from evacuation of a subdural hematoma and bilateral hygromas.