|
FIG 3. Patient 15. A 72-year-old man with Streptococcus mitis (aerobe) bacteremia, infective endocarditis, and multiple miliary pyogenic brain abscesses.
A, Axial contrast-enhanced T1-weighted MR image shows numerous miliary nodules with ring enhancement. The 2 x 2 x 2-cm voxel (box) in the lesion and adjacent brain tissue represents the 1H MR spectroscopic volume of interest.
B and C, In vivo 1H spectra (TR/TE 1600/270 [B] and 1600/135 [C]) show spectral pattern C with a lactate (Lac) peak (1.3 ppm) that is inverted at a TE of 135. The resonances of choline (Cho), creatine (Cr), and N-acetylaspartate (NAA) were interpreted to be caused by partial volume effects of the adjacent brain tissue. The phase reversal does not follow the classic pattern in this case because of the presence of some phase distortion, which presumably originated from the eddy current effect. Multiple small peaks at various frequencies are present; these peaks may represent noise or unassigned metabolites.
D, Axial contrast-enhanced T1-weighted MR image obtained 3 months later shows almost complete remission of the formation of diffuse abscesses after antibiotics.
|