Assessment and Comparison Analysis of Cerebral Perfusion SPECT Parameters in Liquidators of the Chernobyl Accident Suffering from Dyscirculatory Encephalopathy Long After Exposure to Radiation

The purpose of the study is to perform comparative analysis of cerebral perfusion SPECT parameters found in liquidators of the Chernobyl accident suffering from dyscirculatory encephalopathy (DEP) long after exposure to radiation and to identify indicators for monitoring their physical condition and assess treatment effectiveness. Materials and methods. We used cerebral single-photon emission computed tomography (SPECT) to examine a group of liquidators of the Chernobyl accident (LCA) and a group of patients who had not been exposed to radiation, all of them suffering from dyscirculatory encephalopathy (DEP). We examined a total of 147 men, including 93 LCAs aged 69.38 (6.42) (the study group) and 54 patients aged 70.70 (7.25) (the comparison group). No differences by age were identified (p = 0.347). The study was performed using General Electric Healthcare Discovery NM/CT 670 Pro. Cerebral scintigraphy was performed using Russian-made Theoxym, 99mTc. Cerebral perfusion imaging was carried out with the help of diacarb (acetazolamide). We compared a total of 22 SPECT parameters. Results. Arterial inflow time in the frontal and back views in both groups increased after taking diacarb by 8.37% (p = 0.138) and 6.62% (p = 0.213) in LCAs and by 15.38% (p = 0.035) and 13.63% (p = 0.037) in the comparison group. Regional cerebral blood flow (rCBF) in the right and left brain hemispheres of LCAs was below the age norm (p = 0.001 and p < 0.001), as well as below the rCBF in the frontal, temporal, parietal, and occipital lobes of the brain in healthy subjects of comparable age (p < 0.001). Average cerebrovascular reserve (CVR) in both groups was lower than the lower end of the normal range (31–75%). Only some of the patients from the comparison group fell within this range: 2.94% of those examined – in the temporal and occipital lobes of the right hemisphere and 8.82% – in the occipital lobe of the left hemisphere. CVR was lower in LCAs than in the comparison group by 14.19 and 14.08% in the frontal lobes of both hemispheres and by 16.31% in the temporal lobe of the left hemisphere; in the occipital lobes, however, it was higher by 29.07 and 12.06%. We found a negative correlation between rCBF and CVR and LCAs’ age, as well as between CVR and radiation dose (p < 0.05). Conclusion. SPECT is a promising method of detecting DEP in LCAs and other patients who have been exposed to radiation, as well as of preventing health complications and assessing treatment effectiveness. A decrease in rCBF and CVR in the frontal and frontotemporal areas of the brain may serve as the criterion for DEP detection.