Correlation between 99Tcm-HMPAO-SPECT brain image and a history of decompression illness or extent of diving experience in commercial divers

• Published in: Occupational and environmental medicine (London, England) Vol. 54; no. 4; pp. 247 - 253
• Main Authors: Shields, T G, Duff, P M, Evans, S A, Gemmell, H G, Sharp, P F, Smith, F W, Staff, R T, Wilcock, S E
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group Ltd 01.04.1997; BMJ Publishing Group; BMJ; BMJ Publishing Group LTD
• Subjects: Adult; Biological and medical sciences; Brain; Brain Diseases - diagnostic imaging; Brain Diseases - epidemiology; Brain Diseases - etiology; Brain scans; Case-Control Studies; Chemical hazards; Computed tomography; Craniocerebral trauma; Decompression Sickness - complications; Decompression Sickness - epidemiology; Decompression Sickness - etiology; Diseases; Diving; Diving - adverse effects; Fumes; Humans; Image analysis; Insults; Medical sciences; Nervous tissues; Occupational Diseases - diagnostic imaging; Occupational Diseases - epidemiology; Occupational Diseases - etiology; Organotechnetium Compounds; Oximes; Perfusion; Pressure reduction; Prevalence; T tests; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Transport. Aerospace. Diving. Altitude; Traumas. Diseases due to physical agents; Radionuclide study; Human; Nervous system diseases; Occupational exposure; Photon; Trauma; Physical agent; Decompression sickness; Diving; Diagnosis; Professional activity; Antecedent; Occupational medicine; Barotrauma; Brain (vertebrata); Emission tomography
• ISSN: 1351-0711; 1470-7926
• DOI: 10.1136/oem.54.4.247

OBJECTIVES: To explore the use of 99technetiumm-hexamethyl propylene amine oxime single photon computed tomography (HMPAO-SPECT) of the brain as a means of detecting nervous tissue damage in divers and to determine if there is any correlation between brain image and a diver's history of diving or decompression illness (DCI). METHODS: 28 commercial divers with a history of DCI, 26 divers with no history of DCI, and 19 non-diving controls were examined with brain HMPAO-SPECT. Results were classified by observer assessment as normal (I) or as a pattern variants (II-V). The brain images of a subgroup of these divers (n = 44) and the controls (n = 17) were further analysed with a first order texture analysis technique based on a grey level histogram. RESULTS: 15 of 54 commercial divers (28%) were visually assessed as having HMPAO-SPECT images outside normal limits compared with 15.8% in appropriately identified non-diver control subjects. 18% of divers with a history of DCI were classified as having a pattern different from the normal image compared with 38% with no history of DCI. No association was established between the presence of a pattern variant from the normal image and history of DCI, diving, or other previous possible neurological insult. On texture analysis of the brain images, divers had a significantly lower mean grey level (MGL) than non-divers. Divers with a history of DCI (n = 22) had a significantly lower MGL when compared with divers with no history of DCI (n = 22). Divers with > 14 years professional diving or > 100 decompression days a year had a significantly lower MGL value. CONCLUSIONS: Observer assessment of HMPAO-SPECT brain images can lead to disparity in results. Texture analysis of the brain images supplies both an objective and consistent method of measurement. A significant correlation was found between a low measure of MGL and a history of DCI. There was also an indication that diving itself had an effect on texture measurement, implying that it had caused subclinical nervous tissue damage.