Evaluating contrast-enhancing brain lesions in patients with AIDS by using positron emission tomography.
OBJECTIVE
To determine whether a noninvasive method for evaluating contrast-enhancing brain lesions in patients with the acquired immunodeficiency syndrome (AIDS) can accurately differentiate between lymphoma and nonlymphoma diagnoses. This method is based on Toxoplasma serologic testing and positron emission tomography.


METHODS
Prospective, nonrandomized, criterion-standard clinical study.


METHODS
An academic center in the mid-southeastern United States.


METHODS
20 patients with AIDS and contrast-enhancing brain lesions.


METHODS
Positron emission tomographic scanning and Toxoplasma serologic testing.


METHODS
Diagnoses were confirmed by clinical response, autopsy, or brain biopsy.


RESULTS
Eight patients had a confirmed diagnosis of toxoplasmosis, six had lymphoma, four had other diagnoses, and two were not evaluable. Seven of eight patients with toxoplasmosis had positron emission tomographic scans; all of these scans showed hypometabolic lesions consistent with a nonlymphoma diagnosis. The six patients with lymphoma all had hypermetabolic lesions on positron emission tomographic scans. The difference between these two sets of results was statistically significant (P < 0.001, Fisher exact test, two-tailed). The anti-Toxoplasma titer was greater than or equal to 1:4 in all patients with confirmed toxoplasmosis who had serologic testing and in three of six patients with lymphoma.


CONCLUSIONS
Evaluating contrast-enhancing brain lesions in patients with AIDS by using Toxoplasma serologic testing and positron emission tomography can accurately guide therapy and obviate the need for most brain biopsies in these patients. A larger, national, multicenter study is needed to confirm our findings and to determine the effect of earlier diagnosis and treatment on morbidity and mortality in patients with AIDS and primary central nervous system lymphoma.
Pierce
M A
MA
Vanderbilt University School of Medicine, Nashville, Tennessee, USA.
Johnson
M D
MD
Maciunas
R J
RJ
Murray
M J
MJ
Allen
G S
GS
Harbison
M A
MA
Creasy
J L
JL
Kessler
R M
RM
D017088:AIDS-Related Opportunistic Infections / Q000000981:diagnostic imaging* / Q000188:drug therapy; D000328:Adult; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D003937:Diagnosis, Differential; D006801:Humans; D016483:Lymphoma, AIDS-Related / Q000000981:diagnostic imaging* / Q000532:radiotherapy; D008875:Middle Aged; D011446:Prospective Studies; D015899:Tomography, Emission-Computed, Single-Photon; D014122:Toxoplasma / Q000302:isolation & purification; D016781:Toxoplasmosis, Cerebral / Q000000981:diagnostic imaging* / Q000188:drug therapy
D000913:Antibodies, Protozoan