|Vol. 4, Issue 2, Article 1||Saleem, S.|
Few MR spectroscopy investigations of NBD have been published. The preliminary results of these studies have shown potential value of MR spectroscopy in diagnosis NBD (51, 55-59).
In the acute phase of parenchymal NBD, reduced NAA/Cr ratios are seen in comparison with the normal or unaffected contralateral side. These changes subsequently normalize following clinical and radiological recovery. Although the MRS findings are not pathognomonic for NBD, they confirm brain involvement. Monitoring changes in NAA/Cr ratio with MRS may reflect the effects of therapy during acute illness in NBD (56, 57). Drop of NAA, indicative of axonal loss, in concert with elevation in lipid, myoinositol and choline/creatine ratios (non specific markers of myelin breakdown) indicate possible demyelination in NBD (58, 59). Moreover, biochemical abnormalities of the brain in NBD may occur even when structural changes are absent. Where no lesion is found on MRI, MRS may show significant decreases of NAA/Cr ratio in NBD patients compared to healthy subjects. MRS may thus serve to assess sub-clinical neurological involvement in this disease even with normal-appearing brain MRI (57, 59).
In vascular NBD, acute infarcts are characterized by reduction of NAA and Cr compared to the contralateral side as well as the appearance of a lactate peak (Fig 26), indicating disruption of the normal cellular oxidative respiration mechanism, and carbohydrate catabolism (60, 61). The MR spectrum in parenchymal NBD, does not demonstrate a lactate doublet that typically accompanies acute ischemic changes of vascular NBD (51, 58)
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