Abnormal thalamic volume in treatment-naïve boys with Tourette syndrome.

OBJECTIVE: Thalamic abnormality has been implicated in the pathophysiology of Tourette's syndrome (TS). We examined the presence of aberrant thalamic volume from the treatment-naïve boys with TS using magnetic resonance imaging (MRI). METHOD: Volumetric MRI was performed on 18 treatment-naïve boys with TS, aged 7-14 years, and 16 healthy comparison subjects. The anatomical boundaries were then manually parcellated to measure the thalamic volume. RESULTS: Tourette's syndrome subjects had a significantly larger left thalamus in comparison with those of healthy subjects. On the contrary, no group difference was observed from the right thalamic volume. TS subjects also showed a significant reduction in rightward asymmetry in thalamic volume compared with the healthy subjects. CONCLUSION: Our findings provide new evidence of abnormal thalamic volume in pediatric TS.

Tissue temperature monitoring with multiple gradient-echo imaging sequences.

The inherent sensitivity of multiple gradient-echo sequences to the chemical shift is exploited to rapidly map muscle water frequency shifts caused by ultrasonic heating. The use of multiple echoes is shown to offer several advantages over single gradient-echo approaches previously proposed for temperature measurement. An increase in the effective bandwidth significantly reduces aliasing problems observed with single gradient-echo methods in high temperature applications. Of greater significance is the improved immunity to intrascan motion found for multi-echo versus single echo gradient methods, making the former more attractive for clinical applications. Finally, a sensitivity to the presence of multiple spectral components unavailable with single gradient-echo methods is obtained.