Masafumi Harada MD, PhD, Presenter: Nothing to Disclose

Hitoshi Kubo, Abstract Co-Author: Nothing to Disclose

Naomi Morita MD, Abstract Co-Author: Nothing to Disclose

Hiromu Nishitani MD, PhD, Abstract Co-Author: Nothing to Disclose

Tsuyoshi Matsuda, Abstract Co-Author: Nothing to Disclose

Autism is a clinical syndrome defined by disturbance of social behavior, abnormality of language development and elaborate repetitive routines and interests. Gamma-aminobutyric acid (GABA) in autistic patients was measured using MEGA-PRESS on clinical 3T MR apparatus and the density of GABA receptor was evaluated by SPECT after Iomazenil injection. The purposes of this study are to find abnormality of metabolism on GABA in autism and usefulness of the clinical measurement related with GABA metabolism.

Twelve autistic patients (2〜11 y.o., mean 5.2 y.o.) were measured by anatomical MRI and after obtaining informed consents from their parents, single voxel proton MRS including MEGA-PRESS was conducted for GABA observation. As age-matched normal controls, eight children (3〜12 y.o., mean 6.6 y.o.) who show no neurological abnormality and anatomical disorder by MRI were recruited after getting informed consents. The measured locations were left frontal lobe and left basal ganglia. The quantification of signals in the difference and original spectrum by MEGA-PRESS were conducted by LCModel and the GABA index calibrated by NAA signals (GABA/NAA) was calculated. Eight patients and six age-matched children were conducted by SPECT with I-123 Iomazenil administration.

The GABA concentration and GABA index (=GABA/NAA) in the frontal lobe on autistic patients were lower than that on normal controls (p0.1). The activity ratio of the frontal lobe/cerebellum in autism by SPECAT imaing was lower than that of the normal controls. This finding on the GABA receptor imaging was almost consistent with the results of GABA concentration and index by proton MRS with an editing technique, suggesting the decrease of neurotransmitter activity related with GABA in the frontal lobe on autistic patients.

Proton MRS (MEGA-PRESS) and iomazenil SPECT imaging suggested the functional abnormality in the frontal lobe of autistic patients.

Proton MRS with an editing technique and the receptor SPECT imaging will be useful to detect functional abnormality in autistic patiens.

Harada, M, Kubo, H, Morita, N, Nishitani, H, Matsuda, T, Abnormality Related with Neurotransmittter Activity in the Frontal Lobe of Autistic Patients Observed by Proton MRS with Editing Technique and a Receptor SPECT Imaging.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5012534.html