Brain MRI signal abnormalities and right-to-left shunting in asymptomatic military divers.
BACKGROUND
We conducted a controlled study to assess the prevalence of brain MRI hyperintense signals and their correlation with right-to-left shunting (RLS) in military divers.


METHODS
We prospectively enrolled 32 asymptomatic military divers under 41 yr of age and 32 non-diving healthy subjects matched with respect to age and vascular disease risk factors. We examined both groups with a 3-Tesla brain MRI; RLS was detected using transcranial pulsed Doppler in divers only.


RESULTS
Hyperintense spots were observed in 43.7% of the divers and 21.8% of the control subjects. In particular, divers with significant shunting exhibited a higher prevalence of hyperintensities compared to those with slight or no RLS (75% vs. 25%, respectively). Linear trend analysis also revealed a positive correlation between focal white matter changes, determined using a validated visual rating scale and the RLS grade.


CONCLUSIONS
Healthy military divers with a hemodynamically relevant RLS have an increased likelihood of cerebral hyperintense spots compared to age-matched normal subjects. The clinical relevance of these MRI signal abnormalities and their causal relationship with diving remain unclear.
Department of Diving and Hyperbaric Medicine, Ste. Anne's Military Hospital, Toulon, France. gempp@voila.fr
Emmanuel
E
Gempp
Fabrice
F
Sbardella
Eric
E
Stephant
Pascal
P
Constantin
Sebastien
S
De Maistre
Pierre
P
Louge
Jean-Eric
JE
Blatteau
D000328:Adult; D001930:Brain Injuries / Q000209:etiology; D016022:Case-Control Studies; D054022:Cerebrum / Q000293:injuries*; D004242:Diving / Q000009:adverse effects*; D054092:Foramen Ovale, Patent / Q000150:complications* / Q000000981:diagnostic imaging; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D014463:Ultrasonography