Študij sprememb dolgoročnega motoričnega spomina in vzorcev aktivacije možganov pri bolnikih s Parkinsonovo boleznijo z uporabo funkcijske magnetne resonance

Zupan, Gašper (author), Šuput, Dušan (mentor), Pirtošek, Zvezdan (comentor)

Parkinsonova bolezen (PB) je pogosta nevrodegenerativna bolezen možganov, pri kateri pride do zmanjšanja količine nevromelanina (NM) v substanci nigri (SN). Številne magnetnoresonančne (MR) študije so z uporabo T1-obteženih sekvenc dokazale zmanjšano površino in prostornino SN pri bolnikih s PB ter znižano intenziteto signala SN. Motorični simptomi so glavna značilnost PB. Nekatere študije s funkcijsko magnetno resonanco (fMRI) so pri bolnikih s PB poročale o spremenjenih vzorcih aktivacije v možganih med motoričnim učenjem, vendar ni poznana fMRI študija, ki bi to preučevala v daljšem časovnem obdobju. V naši študiji so bile strukturne slike SN zajete z uporabo MR tomografa z jakostjo magnetnega polja 3 tesla s T1-obteženo sekvenco z dodatnim presaturacijskim inverznim pulzom (SPIR). Strukturne spremembe SN pri PB smo kvantificirali z ročno in polavtomatsko segmentacijsko metodo, ki temelji na principu statističnih podpisov ter ne potrebuje standardizacije. Analiza krivulje natančnosti in priklica (angl. »ROC analysis«) je bila uporabljena za določitev občutljivosti in specifičnosti obeh metod. Snemanje fMRI smo izvajali med izvajanjem motoričnega zaporedja, ki je vsebovalo osem zgibov prstov na eni roki. Med Dnevom 0 in Dnevom 28 so preiskovanci doma dnevno vadili motorični vzorec, med Dnevom 28 in Dnevom 90 pa vzorca niso več vadili. Snemanje fMRI je potekalo na Dan 0, Dan 28 in Dan 90. Bolniki s PB so imeli v primerjavi z zdravimi preiskovanci (ZP) znižano površino (37,7 ± 8,0 in 56,9 ± 6,6 mm2) in prostornino (235,1 ± 45,4 in 382,9 ± 100,5 mm3) SN. Za površino SN je občutljivost znašala 91,7 %, specifičnost pa 95 %. Za prostornino SN je občutljivost znašala 91,7%, specifičnost pa 90 %. Pri analizi podatkov fMRI smo pri bolnikih s PB v primerjavi z ZP na Dan 0 opazili povišano aktivacijo v parahipokampalnem režnju in hipokampusu. Na Dan 28 in Dan 90 smo pri bolnikih s PB ugotovili znižano aktivacijo v spodnjem parietalnem, zadnjem cingulatnem režnju in prekuneusu. Povišana aktivacija v parahipokampalnem režnju je bila pri bolnikih s PB zabeležena tudi na Dan 28. Z analizo strukturnih slik smo ugotovili, da sta tako ročna kot polavtomatska segmentacijska metoda SN zanesljivi pri razlikovanju med bolniki s PB in ZP. Obe metodi imata visoko občutljivost ter specifičnost. Pri bolnikih s PB povišana aktivacija v zgodnjih fazah učenja motoričnega vzorca najverjetneje predstavlja kompenzatorni mehanizem. V poznih fazah učenja in priklica pa znižana aktivacija pri bolnikih lahko predstavlja nezadostno delovanje izvršilnih funkcij.

• Language: Slovenian
• Keywords: parkinsonova bolezen, magnetna resonanca, nevroradiologija
• Work type: Doctoral dissertation
• Organization: MF - Faculty of Medicine
• Year: 2020
• PID: 20.500.12556/RUL-116914
• Publication date in RUL: 16.06.2020

Secondary language

• Language: English
• Title: An fMRI study of long-term motor learning and cerebral activation patterns in patients with Parkinson’s disease

Abstract

Parkinson's disease (PD) is a common neurodegenerative disease with a reduction of neuromelanin (NM) in the substantia nigra (SN). Using T1-weighted sequences, several magnetic resonance (MR) studies demonstrated reduced surface and volume of SN in PD and decreased signal intensity of SN. Motor system dysfunction is a main complaint in PD. Some functional magnetic resonance (fMRI) studies showed altered brain activation patterns during motor learning in PD, however long-term effects of motor learning in PD have not been yet explored with fMRI. In our study, T1-weighted images with spectral presaturation with inversion recovery (SPIR) pulse were acquired on a 3T MR scanner to investigate structural changes of SN. Structural changes of SN were quantified with manual and novel semi-automatic atlas-free local statistics signature-based segmentation methods. Receiver operating characteristic (ROC) analysis was performed to determine the sensitivity and specificity of both methods. fMRI activation patterns in PD were assessed over a period of 90 days. fMRI data was acquired during execution of finger-tapping sequence that was composed of eight finger taps. Between Day 0 and Day 28, subjects were asked to daily train finger-tapping motor sequence at home. Between Day 28 and Day 90, subjects were instructed to stop with the training at home. fMRI data was acquired on Day 0, Day 28 and Day 90. PD patients had lower surface (37.7 ± 8.0 vs. 56.9 ± 6.6 mm2) and volume (235.1 ± 45.4 vs. 382.9 ± 100.5 mm3) of SN than healthy controls. For surface, sensitivity and specificity were 91.7 % and 95 %, respectively. For volume, sensitivity and specificity were 91.7 % and 90 %, respectively. In fMRI part of the study, higher activation of parahippocampal gyrus and hippocampus were detected on Day 0 in patients with PD in comparison to healthy controls. On Day 28 and Day 90, lower activation was found in PD patients in inferior parietal lobe, posterior cingulate cortex and precuneus. On Day 28, higher activation in parahippocampal gyrus was noted as well. Manual and semi-automatic segmentation methods of SN reliably distinguish between PD patients and HC. ROC analysis shows high sensitivity and specificity of both methods. In the fMRI study, several areas with higher activation in PD could represent compensatory mechanisms in PD. In later stages of motor memory formation, lower activation may reflect general dysfunction of executive functions in PD.

• Keywords: Parkinson's disease, magnetic resonance, neuroradiology