Rjs. Chinn et al., TOXOPLASMOSIS AND PRIMARY CENTRAL-NERVOUS-SYSTEM LYMPHOMA IN HIV-INFECTION - DIAGNOSIS WITH MR SPECTROSCOPY, Radiology, 197(3), 1995, pp. 649-654
PURPOSE: To differentiate intracranial lymphoma from Toxoplasma gondii
lesions in patients infected with the human immunodeficiency virus, b
y means of localized spin-echo proton magnetic resonance (MR) spectros
copy. MATERIALS AND METHODS: Twenty-seven lesions were studied (18 T g
ondii lesions, nine lymphoma lesions) at 1.5 T. Spectra were acquired
at an echo time of 135 msec from voxels centered on the lesions. Both
visual analysis and spectral fitting were used to obtain metabolite ra
tios for choline (Cho), creatine (Cr), N-acetyl (NA), lactate, and lip
ids. RESULTS: Three spectral categories were seen. One had large lipid
peaks with suppression of other metabolites. Another had an elevated
Cho/Cr ratio with relatively diminished NA. The third had features of
the other two. Examples of each spectrum type were acquired from both
T gondii and lymphoma lesions. Neither method of analysis allowed diff
erentiation between lesion types. MR spectroscopy showed an overlap of
spectra. CONCLUSION: The authors conclude that toxoplasmosis and lymp
homa cannot be differentiated with spin-echo proton MR spectroscopy at
135 msec.