1H magnetic resonance spectroscopy investigation of the dorsolateral prefrontal cortex in bipolar disorder patients.
BACKGROUND
Magnetic resonance spectroscopy studies (MRS) reported abnormally low levels of N-acetylaspartate (NAA, a marker of neuronal integrity) in dorsolateral prefrontal cortex (DLPFC) of adult bipolar patients, suggesting possible neuronal dysfunction. Furthermore, recent MRS reports suggested possible lithium-induced increase in NAA levels in bipolar patients. We examined with in vivo (1)H MRS NAA levels in the DLPFC of adult bipolar patients.


METHODS
Ten DSM-IV bipolar disorder patients (6 lithium-treated, 4 drug-free) and 32 healthy controls underwent a short echo-time 1H MRS session, which localized an 8 cm3 single-voxel in the left DLPFC using a STEAM sequence.


RESULTS
No significant differences between the two groups were found for NAA, choline-containing molecules (GPC+PC), or phosphocreatine plus creatine (PCr+Cr) (Student t-test, p > 0.05). Nonetheless, NAA/PCr+Cr ratios were significantly increased in lithium-treated bipolar subjects compared to unmedicated patients and healthy controls (Mann-Whitney U-test, p < 0.05).


CONCLUSIONS
Relatively small sample size may have reduced the statistical power of our analyses and the utilization of a single-voxel approach did not allow for the examination of other cortical brain areas.


CONCLUSIONS
This study did not find abnormally reduced levels of NAA in left DLPFC of adult bipolar patients, in a sample of patients who were mostly on medications. However, elevated NAA/PCr+Cr ratios were shown in lithium-treated bipolar patients. Longitudinal 1H MRS studies should further examine NAA levels in prefrontal cortex regions in untreated bipolar patients before and after mood stabilizing treatment.
Brambilla
Paolo
P
Division of Mood and Anxiety Disorders, Department of Psychiatry, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
Stanley
Jeffrey A
JA
Nicoletti
Mark A
MA
Sassi
Roberto B
RB
Mallinger
Alan G
AG
Frank
Ellen
E
Kupfer
David
D
Keshavan
Matcheri S
MS
Soares
Jair C
JC
D000328:Adult; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000032:analysis / Q000187:drug effects / Q000378:metabolism*; D001714:Bipolar Disorder / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D016022:Case-Control Studies; D003401:Creatine / Q000032:analysis / Q000187:drug effects / Q000378:metabolism; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D010725:Phosphocreatine / Q000032:analysis / Q000187:drug effects / Q000378:metabolism; D017397:Prefrontal Cortex / Q000000981:diagnostic imaging* / Q000473:pathology*; D011859:Radiography
D010725:Phosphocreatine; D001224:Aspartic Acid; C000179:N-acetylaspartate; D003401:Creatine