Ketosis and epilepsy:: 31P spectroscopic imaging at 4.1 T

Purpose: To determine whether changes in the high-energy phosphates occur with use of the ketogenic diet in patients with intractable epilepsy. Methods: P-31 magnetic resonance spectroscopic imaging studies were performed at 4.1 T in seven patients with intractable epilepsy (four Lennox-Gastaut syndrome, one absence, one primary generalized tonic-clonic, and one partial complex) before and after institution of the ketogenic diet. Coronal H-1 anatomic imaging also was performed to provide correlation to the P-31 data. Results: Taking the patients as a group, the ratio of phosphocreatine (PC)/gamma-adenosine triphosphate (ATP) measured at baseline (regular diet) compared with that measured after the ketogenic diet showed a small but significant increase from 0.61 +/- 0.08 to 0.69 +/- 0.08 (p < 0.05). Comparing the ratio of PCr inorganic phosphorus (P-i) measured at baseline with the postketogenic diet, there was a significant increase from 2.45 +/- 0.27 to 2.99 +/- 0.44 (p < 0.05). Conclusions: As a group, improvement of energy metabolism occurs with use of the ketogenic diet. This is in agreement with the chronic ketosis studies performed earlier in rodents.