Central nervous system lymphoma characterization by diffusion-weighted imaging and MR spectroscopy.
OBJECTIVE
The characterization and differentiation of central nervous system (CNS) lymphoma has important diagnostic, therapeutic, and prognostic significance. The purpose of this study is to characterize the diffusion-weighted imaging (DWI) and MR spectroscopic (MRS) findings in CNS lymphoma.


METHODS
Twenty consecutive patients (male [n= 12], female [n= 8]) with histopathologically proven CNS lymphoma were retrospectively evaluated during this study from July 2005 to April 2007. Patients included immunocompromised (n= 9) and immunocompetent (n= 11) individuals. MR Imaging (pretreatment n= 13), pre- and post-treatment (n= 7) included DWI (n= 20) (b = 1000s/mm2) and ADC (apparent diffusion coefficient) maps of all patients. MRS was performed (n= 10) with PRESS (point-resolved spectroscopy) sequence (multivoxel n= 8, single voxel n= 2) with a TE of 144 msec. All patients were histopathologically confirmed to have lymphoma by biopsy.


RESULTS
Areas of restricted diffusion were observed in 90 % (n= 18/20) on pretreatment scans. The diffusion restriction was variable on post-treatment scans. Median metabolite ratios in 10 patients were Cho/Cr- 2.12, NAA/Cho - .49, and NAA/Cr - 1.64. Presence of lactate or lipid was noted in 90 % (n= 9/10). Sites of lesion location were subcortical white matter (n= 6), basal ganglia (n= 4), corpus callosum (n= 3), extra-axial space including cavernous sinus (n= 5), cerebellum (n= 1), and lateral ventricle (n= 1).


CONCLUSIONS
Restricted diffusion is a consistent imaging finding in CNS lymphoma in immunocompetent patients. Spectroscopy is helpful in initial imaging diagnosis and post-treatment surveillance. These lesions are usually paraventricular in location. MR imaging appearances differ among immunocompetent and immunosuppressed individuals in most cases.
Zacharia
T Thomas
TT
Neuroradiology, Mount Sinai Medical Center, New York, NY, USA. ttz100@yahoo.com
Law
Meng
M
Naidich
Thomas P
TP
Leeds
Norman E
NE
D000328:Adult; D000368:Aged; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D001706:Biopsy; D001921:Brain / Q000473:pathology; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000628:therapy; D002794:Choline / Q000378:metabolism; D003401:Creatine / Q000378:metabolism; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007121:Immunocompetence; D007165:Immunosuppression Therapy; D007294:Inositol / Q000378:metabolism; D019344:Lactic Acid / Q000378:metabolism; D016483:Lymphoma, AIDS-Related / Q000175:diagnosis / Q000473:pathology / Q000628:therapy; D016393:Lymphoma, B-Cell / Q000175:diagnosis* / Q000473:pathology / Q000628:therapy; D016399:Lymphoma, T-Cell / Q000175:diagnosis* / Q000473:pathology / Q000628:therapy; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies
D001224:Aspartic Acid; D019344:Lactic Acid; D007294:Inositol; C000179:N-acetylaspartate; D003401:Creatine; D002794:Choline