Proton MR spectroscopy of gadolinium-enhanced multiple sclerosis plaques.

Magnetic resonance (MR) imaging and proton MR spectroscopy were performed in 14 patients with clinically definite multiple sclerosis (MS). Prominent resonances in the 0.5-2.0-ppm region were seen in the spectra of six of nine gadopentetate dimeglumine-enhanced plaques in seven patients. These resonances were presumed to originate in lipids and other myelin breakdown products. Similar resonances were detected in only seven of 21 unenhancing plaques. The more frequent presence of such signals in the gadolinium-enhanced regions indicates that myelin breakdown is often associated with the inflammation that occurs in early stages of MS plaque evolution. It remains uncertain, however, whether active inflammation as indicated by gadolinium enhancement is a necessary precursor of myelin breakdown as detected at MR spectroscopy. Quantitative spectral analysis did not indicate statistically significant differences in N-acetyl aspartate and choline levels relative to creatine plus phosphocreatine between healthy volunteers and MS patients.