RESEARCH - MRS finds that smoke gets in the brain as well as the eyes

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MRS finds that smoke gets in the brain as well as the eyes

11/28/2006

CHICAGO - Proton magnetic resonance spectroscopy (H-MRS) has provided the

first proof that smoking changes the chemistry of the brain -- but the good

news is that the changes can be reversed, according to researchers from

Germany.

Concentrations of a key brain metabolite -- N-acetylaspartate (NAA) -- are

significantly lower in brains of smokers than in the brains of age-matched

controls, said Dr. Okan Gür of the department of radiology at the University

of Bonn in Germany. He reported the findings Tuesday at the 2006 RSNA

meeting.

" But ... MRS conducted after six months of abstinence from smoking found

that NAA levels had returned to normal, " he said.

Gür and colleagues performed H-MRS in the second week after smoking

cessation and additionally six months later on smokers with an average of 25

pack years of smoking history (n = 43) on a 1.5-tesla MR system (Gyroscan

ACS-NT, Philips Medical Systems, Andover, MA) and on 35 healthy controls.

Two volumes of interest (VOI) were placed in the left prefrontal cortex and

the anterior cingulate cortex to assess absolute and relative concentrations

of NAA, total creatine (tCr), and choline-containing compounds.

At baseline, NAA concentration in the anterior cingulate cortex was 13.3

mmol/L in smokers and 13.9 mmol/L in controls (p = 0.01), Gür said. After

six months, smokers who had remained smoke-free had NAA concentrations of

13.8 mmol/L, which was roughly comparable to controls.

But among 11 smokers who relapsed, the mean NAA concentration was 13.2

mmol/L, he said.

No significant differences were seen in NAA concentrations in the left

prefrontal cortex, but there was a difference in total creatine

concentrations in the prefrontal cortex that was associated with an

increased risk of relapse. Smokers who relapsed had mean baseline total

creatine levels of 7.6 mmol/L versus 7.0 mmol/L for smokers who successfully

stopped smoking.

And among smokers who successfully quite, total creatine concentration was

8.2 mmol/L at six months.

Total creatine is " associated with stress, so it suggests that smokers who

were more stressed at baseline had more difficulty quitting and that

successful smoking cessation is itself a stressful event, " Gür said.

By M. Conroy

AuntMinnie.com contributing writer

November 28, 2006

http://www.auntminnie.com:80/index.asp?Sec=rca & Sub=rsna_2006 & Pag=dis & ItemId=7374\

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Mayo Clinic in Rochester

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s Hopkins Medicine

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