Cerebral diffusion and perfusion deficits in North Sea divers

Area of Science:

• Neurology
• Radiology
• Diving Medicine

Background:

• Diving carries a risk of cerebral decompression illness, with divers experiencing more neurological symptoms than controls.
• Potential mechanisms include microvascular dysfunction from gas microembolism and hyperoxia, leading to cerebral diffusion and perfusion deficits.

Purpose of the Study:

• To determine if functional microvascular and microstructural derangements are more common in symptomatic divers.
• Investigate the prevalence of these abnormalities in former divers.

Main Methods:

• Magnetic resonance imaging (MRI) was used on 91 former divers and 45 controls.
• Generated parametric images for apparent diffusion coefficient (ADC), cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT).
• Voxel-wise ANCOVA analysis identified statistically significant group differences (P < 0.05, FDR corrected).

Main Results:

• Significant regional differences were observed in ADC and perfusion parameters between divers and controls.
• Widespread ADC differences were noted in white matter, hippocampus, and cerebellum.
• Perfusion differences were localized to smaller clusters in the cerebellum, putamen, and watershed regions.

Conclusions:

• Diffusion- and perfusion-weighted imaging identified regional functional abnormalities in divers.
• Partial overlap was found between diffusion and perfusion abnormalities.
• These findings may explain long-term clinical symptoms reported by professional divers.