Association between right-to-left shunts and brain lesions in sport divers.
BACKGROUND
Recent studies suggest that healthy sport divers may develop clinically silent brain damage, based on the association between a finding of multiple brain lesions on MRI and the presence of right-to-left shunt, a pathway for venous gas bubbles to enter the arterial system.


METHODS
We performed echocontrast transcranial Doppler sonography in 42 sport divers to determine the presence of a right-to-left shunt. Cranial MRI was carried out using a 1.5 T magnet. A lesion was counted if it was hyperintense on both T2-weighted and T2-weighted fluid attenuated inversion recovery sequences. To test the hypothesis that the occurrence of postdive arterial gas emboli is related to brain lesions on MRI, we measured postdive intravascular bubbles in a subset of 15 divers 30 min after open water scuba dives.


RESULTS
Echocontrast transcranial Doppler sonography revealed a right-to-left shunt in 16 of the divers (38%). Only one hyperintensive lesion of the central white matter was found and that was in a diver with no evidence of a right-to-left shunt. Postdive arterial gas emboli were detected in 3 out of 15 divers; they had a right-to-left shunt, but no pathologic findings on cranial magnetic resonance imaging.


CONCLUSIONS
Our data support the theory that right-to-left shunts can serve as a pathway for venous gas bubbles into the arterial circulation. However, we could not confirm an association between brain lesions and the presence of a right-to-left shunt in sport divers.
Gerriets
Tibo
T
Department of Neurology, Justus-Liebig-University Giessen, Am Steg 20, 35390 Giessen, Germany. Tibo.Gerriets@neuro.med.uni-giessen.de
Tetzlaff
Kay
K
Hutzelmann
Alfred
A
Liceni
Thomas
T
Kopiske
Gerrit
G
Struck
Niklas
N
Reuter
Michael
M
Kaps
Manfred
M
D000328:Adult; D001921:Brain / Q000098:blood supply* / Q000473:pathology*; D001927:Brain Diseases / Q000209:etiology / Q000503:physiopathology*; D002536:Cerebral Arteries / Q000002:abnormalities*; D003287:Contrast Media / Q000008:administration & dosage; D003665:Decompression Sickness / Q000209:etiology / Q000503:physiopathology*; D004242:Diving / Q000009:adverse effects*; D004453:Echoencephalography; D004618:Embolism, Air / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D018608:Ultrasonography, Doppler
D003287:Contrast Media