Objective: to determine the early signs of structural changes in brain white matter in small vessel disease associated with arterial hypertension and exposure to ionizing radiation using DTI-MRI.
Materials and methods: 45 patients (mean age (57.56 ± 6.34) years) with small vessel disease (SVD) associatedwith arterial hypertension (AH) were examined: group I - 20 patients, participants of liquidation of the accident atthe Chornobyl nuclear power plant (Chornobyl clean-up workers); group II - 25 patients not exposed to ionizingradiation. MRI was performed on an Ingenia 3T tomograph («Philips»). The fractional anisotropy (FA) was determined in the main associative and commissural pathways, periventricular prefrontal areas (fasciculus fronto-occipitalis superior / anterior - f. FO ant., corona radiata anterior - CR ant.) and semioval centers (SC).
Results: No signs of cerebral cortex or brain white matter (WM) atrophy, intracerebral microhemorrhages, and widespread areas of leukoaraiosis consolidation were observed in the examined patients. In the Chornobyl clean-up workers a larger number of foci of subcortical leukoaraiosis was visualized (80 %) on MRI images including multiple -8 (40 %), > 0.5 cm - 10 (50 %), with signs of consolidation - 5 (25 %). The results of the FA analysis in semiovalcenters showed its significant decrease in the patients of groups I and II (p < 0,007), regardless of the presence orabsence of visual signs of subcortical leukoaraiosis (ScLA) (III gr.: 253-317, p < 0.00001; IV gr.: 287- 375,p < 0.001). FA indicators in f. FO ant. and CR ant. in the patients of groups I and II differed insignificantly but weresubstantially lower than controls (p < 0.05). FA was significantly lower, compared to reference levels, in visuallyunchanged f. FO ant. (0.389-0.425; p = 0.015) and CR ant. (0.335-0.403; p = 0.05). In patients with AH-associated SVD of middle age, regardless of the effects of ionizing radiation, no significant changes in FA in the mainWM associative and commissural pathways were found (p > 0.05).
Conclusions: DTI-MRI allows to detect early signs of structural changes in the white matter of the brain - a significant decrease in fractional anisotropy indicators in visually unchanged periventricular and subcortical areas. Themain associative and commissural pathways of the brain remain intact in the absence of widespread consolidatedfoci of leukoaraiosis and lacunar infarctions. The negative impact of ionizing radiation on the course of SVD associated with arterial hypertension is manifested by more active processes of WM disorganization: the prevalence andtendency to the consolidation of periventricular and subcortical leukoaraiosis foci, a significant FA decrease in semioval centers.
Meta: vyznachennia rannikh oznak strukturnykh zmin biloï rechovyny golovnogo mozku pry asotsiĭovaniĭ z arterial'noiu gipertenziieiu ta ionizuiuchym vyprominiuvanniam khvorobi malykh sudyn iz zastosuvanniam dyfuziĭno-tenzornoïmagnitno-rezonansnoï tomografiï (DT-MRT).Materialy ta metody. Obstezheno 45 patsiientiv (seredniĭ vik – (57,56 ± 6,34) rokiv) z asotsiĭovanoiu z arterial'noiu gipertenziieiu (AG) khvoroboiu malykh sudyn (KhMS): I gr. – 20 patsiientiv, uchasnykiv likvidatsiï avariï na Chornobyl's'kiĭ atomniĭ elektrostantsiï (ULNA na ChAES); II gr. – 25 khvorykh, shcho ne zaznaly vplyvu ionizuiuchogo vyprominiuvannia. MRT vykonuvaly na tomografi Ingenia 3T («Philips»). Vyznachennia fraktsiĭnoï anizotropiï (FA)zdiĭsniuvaly v osnovnykh asotsiatyvnykh i komisural'nykh providnykh shliakhakh, peryventrykuliarnykh prefrontal'nykhdiliankakh (fasciculus frontooccipitalis superior/anterior – f. FO ant., corona radiata anterior – CR ant.) i semioval'nykh tsentrakh (SC).Rezul'taty. U obstezhenykh patsiientiv ne zafiksovano oznak atrofiï kory abo biloï rechovyny golovnogo mozku(BRGM), intratserebral'nykh mikrogemoragiĭ i poshyrenykh zon konsolidatsiï oseredkiv leĭkoareozu. V ULNA naChAES na MRT-zobrazhenniakh vizualizovano bil'she chyslo oseredkiv subkortykal'nogo leĭkoareozu (80 %); u t. ch.mnozhynnykh – 8 (40 %), > 0,5 sm – 10 (50 %), z oznakamy konsolidatsiï – 5 (25 %). Rezul'taty vyznachennia FA v semioval'nykh tsentrakh prodemonstruvaly dostovirne ïï zmenshennia u patsiientiv I ta II grup (p < 0,007), nezalezhnovid naiavnosti abo vidsutnosti vizual'nykh oznak SkLA (III gr.: 253–317, p < 0,00001; IV gr.: 287–375, p < 0,001).Pokaznyky FA f. FO ant. i CR ant. patsiientiv I ta II grup vidriznialys' nedostovirno, ale buly znachno nyzhchymy vidkontrol'nykh (p < 0,05). Dostovirno mensha, porivniano z referentnymy rivniamy, FA u vizual'no nezminenykh f. FOant. (0,389–0,425; p = 0,015) i CR ant. (0,335–0,403; p = 0,05). U khvorykh na AG-asotsiĭovanu KhMS seredn'ogo viku,nezalezhno vid vplyvu ionizuiuchogo vyprominiuvannia, ne konstatovano dostovirnykh zmin FA v osnovnykh asotsiatyvnykh i komisural'nykh providnykh traktakh BRGM (p > 0,05).Vysnovky. Dyfuziĭno-tenzorna magnitno-rezonansna tomografiia dozvoliaie vyiavyty ranni oznaky strukturnykhzmin biloï rechovyny golovnogo mozku – dostovirne zmenshennia pokaznykiv fraktsiĭnoï anizotropiï u vizual'nonezminenykh peryventrykuliarnykh i subkortykal'nykh viddilakh. Osnovni asotsiatyvni ta komisural'ni providnitrakty GM zalyshaiut'sia neushkodzhenymy za vidsutnosti poshyrenykh konsolidovanykh oseredkiv leĭkoareozu talakunarnykh infarktiv. Negatyvnyĭ vplyv ionizuiuchogo vyprominiuvannia na perebig asotsiĭovanoï z AG KhMS realizuiet'sia bil'sh aktyvnymy protsesamy dezorganizatsiï BRGM: poshyrenist' ta skhyl'nist' do konsolidatsiï oseredkivperyventrykuliarnogo ta subkortykal'nogo leĭkoareozu, dostovirne zmenshennia FA v semioval'nykh tsentrakh.
Keywords: DTI; MRI; arterial hypertension; fractional anisotropy; ionizing radiation; small vessel disease; white matter of the brain.
I. M. Dykan, Y. I. Golovchenko, K. M. Loganovsky, O. V. Semonova, L. A. Myronyak, T. M. Babkina, K. V. Kuts, I. O. Kobzar, M. V. Gresko, T. K. Loganovska, S. V. Fedkiv.