Magnetic resonance spectroscopy in attention deficit hyperactivity disorder

THESES

Magnetic resonance spectroscopy in attention deficit hyperactivity disorder (Abstract)^*. Thesis. Niteroi, 2005.

Marcio Moacyr de Vasconcellos^**

OBJECTIVE: To study the applicability of proton magnetic resonance spectroscopy for the diagnosis of attention deficit/hyperactivity disorder.

METHOD: This case-control study assessed 46 school-aged boys through the DSM-IV symptom questionnaire and diagnostic criteria, pediatric history, physical and neurologic examinations, and a neuropsychologic test equivalent to the Wide Range Achievement Test. After 15 children were excluded and one child abandoned the study, study population consisted of 16 cases (median age 9.0± 1.35 years) and 14 controls (median age 9.0±1.23 years). The imaging study employed a PRESS sequence with a single voxel of 8 cm³ positioned in such a way to include mostly gray matter, echo time of 30 ms, repetition time of 1500 ms, and 128 acquisitions, and three cerebral areas were analyzed: right frontal cortex, left frontal cortex, and left striatum. Peaks and ratios of the following metabolites were computed: N-acetylaspartate, myo-inositol, choline, and creatine. Glutamate changes were also studied. In addition, rates were calculated to compare metabolite ratios among the three cerebral regions.

RESULTS: Myo-inositol/creatine ratio in right frontal cortex was found to be significantly elevated in cases (median 0.69, range 0.60-0.85) in comparison with controls (median 0.66, range 0.56-0.74; p=0.044). Peaks and ratios of other metabolites showed no significant differences. Calculated rates based on metabolite ratios among cerebral regions showed statistical significance for the comparison of N-acetylaspartate/creatine ratio in left striatum with the same ratio in left frontal cortex, and a value lower than 0.810 for this rate was associated with attention deficit/hyperactivity disorder diagnosis (odds ratio=9.33, 95% confidence interval=1.51-57.66, p=0.013).

CONCLUSION: A value lower than 0.810 for the rate based upon division of N-acetylaspartate/creatine ratio in left striatum by the same ratio in left frontal cortex is 9.33 times more likely to be associated with diagnosis of attention deficit/hyperactivity disorder. This rate had a 87.5% sensitivity and 57.1% specificity for ADHD diagnosis. Compared with controls, affected children also showed significant elevation of myo-inositol/creatine ratio in right frontal cortex. Study findings favor the notion of bilateral brain dysfunction in ADHD.

Key words: attention deficit disorder, hyperactivity, child, diagnosis, magnetic resonance spectroscopy.

*

Utilidade da espectroscopia por ressonância magnética no diagnóstico do transtorno de déficit de atenção / hiperatividade (Resumo). Tese de Doutorado, Universidade Federal Fluminense (Área: Neurologia). Orientador: Osvaldo J. M. do Nascimento. Co-Orientador: Jairo Werner Jr.

**

Address: Rua Presidente Backer 337, 24220-045 Niterói RJ, Brasil.

Publication Dates

• Publication in this collection
  02 Aug 2006
• Date of issue
  June 2006