The value of new MRI techniques in adrenoleukodystrophy.

Abstract

To evaluate the significance of new techniques in MRI examinations of the brain in children with X-linked adrenoleukodystrophy (ALD). Five patients aged between 2 and 15 years with childhood ALD were examined with MRI. Following conventional spin-echo (CSE) sequence, a fast spin-echo (FSE) sequence with T2 contrast was performed in four patients, an FSE turbo-inversion-recovery (TIR) sequence in two, magnetization transfer contrast (MTC) imaging in two, and localized proton spectroscopy (MRS) in four patients. FSE compared favorably with CSE with a time saving of 70%. On TIR images the contrast between normal and demyelinated white matter was greater than on CSE and FSE images. Calculated MTC values revealed a severe MTC loss within the demyelinated regions and a moderate reduction in the border zones. In this way, calculation of MTC might be useful to differentiate between edematous changes and areas of irreversible demyelination. MRS revealed a reduction in N-acetylaspartate and an elevation in choline (Cho). The degree of MRS changes paralleled the severity of demyelination. A Cho elevation may precede visible demyelination on T2-weighted images. T2-weighted FSE sequences can replace CSE without any disadvantages and with effective time saving. The indication for MTC imaging and MRS in children with ALD is not yet finally defined. These new techniques may reveal the earliest signs of cerebral involvement or of disease progression, a matter of great importance in selecting the optimal therapeutic approach.