Table 1.

Morphological studies in Parkinson’s disease

Subcortical structures	Ref.	Segmentation methods	Analysis type	Results
Striatum
	Geng et al[12], 2006; Pitcher et al[10], 2012; Owens-Walton et al[11], 2018	Manual	Volume	Reduced volume of bilateral caudate and putamen nuclei
	Sterling et al[13], 2013	Semi-automatic	Volume	Reduced volume of bilateral caudate and putamen nuclei
	Geevarghese et al[15], 2015; Vasconcellos et al[17], 2018; Tanner et al[16], 2017; Melzer et al[30], 2012	Automatic	Volume	Reduced volume of bilateral caudate nuclei
	Oltra et al[35], 2022	Automatic	Volume	Reduced volume of bilateral caudate nuclei (with RBD)
	Lee et al[14], 2014; Garg et al[20], 2015	Automatic	Volume	Reduced volume of bilateral putamen nuclei
	Garg et al[20], 2015	Automatic	Volume	Reduced volume of right putamen nuclei
	Kamps et al[33], 2019	Automatic	Volume	Reduced volume of right putamen nuclei (with RBD severity)
	Kluger et al[34], 2019	Automatic	Volume	Reduced volume of dorsal striatum (with fatigue)
	Messina et al[18], 2011; Menke et al[19], 2014; Nemmi et al[21], 2015; Khan et al[22], 2019; Gong et al[32], 2019	Automatic	Volume	No significant difference in bilateral striatum
	Chung et al[31], 2017	Automatic	Volume	Locally reduction of right caudate nuclei
	Devignes et al[28], 2021	Automatic	Shape	Locally reduction of left caudate nuclei (with cognition)
	Garg et al[20], 2015	Automatic	Shape	Locally reduction of right putamen nuclei
	Gong et al[32], 2019	Automatic	Shape	Locally reduction of bilateral caudate and right putamen nuclei (with RBD)
	Tanner et al[16], 2017	Automatic	Shape	Locally reduction of the lateral and medial caudate nuclei
	Sterling et al[13], 2013	Semi-Automatic	Shape	Locally reduction of the head and dorsal body of caudate nuclei
	Nemmi et al[21], 2015	Automatic	Shape	Locally reduction of the medial surface of left caudate nuclei (with the right UPDRS)
	Tanner et al[16], 2017	Automatic	Shape	Locally reduction of the medial surface of putamen nuclei
	Sterling et al[13], 2013	Semi- Automatic	Shape	Locally reduction of the caudal and ventrolateral putamen nuclei
	Sigirli et al[23], 2021	Automatic	Shape	Locally reduction of the middle-posterior of right putamen nuclei
	Lee et al[14], 2014	Automatic	Shape	Locally reduction of the posterolateral and ventromedial putamen nuclei
	Nemmi et al[21], 2015	Automatic	Shape	Locally reduction of the lateral and medial posterior putamen nuclei (with UPDRS)
	Khan et al[22], 2019	Automatic	Shape	Locally reduction of the caudal-motor and rostral-motor sub-regions
Thalamus
	McKeown et al[43], 2008	Manual	Volume	No significant difference
	Garg et al[20], 2015	Automatic	Volume	Significant difference
	Vasconcellos et al[17], 2018; Mak et al[26], 2014; Sivaranjini et al[27], 2021; Foo et al[45], 2017	Automatic	Volume	Reduced volume of bilateral thalamus
	Niccolini et al[46], 2019	Automatic	Volume	Reduced volume of bilateral thalamus (with non-motor symptom)
	Kamps et al[33], 2019	Automatic	Volume	Reduced volume of left thalamus (with RBD)
	Chen et al[44], 2020	Automatic	Volume	Increased volume (20) of right subnuclei
	Chen et al[44], 2020	Automatic	Volume	Increased volume (21), reduced volume (2) of left subnuclei
	Kaya et al[40], 2019	Manual	Shape	Locally reduction of the dorsolateral of bilateral STN
	Devignes et al[28], 2021	Automatic	Shape	Locally reduction of right thalamus (with cognition)
	Chung et al[31], 2017	Automatic	Shape	Locally reduction of bilateral thalamus (with cognition)
	McKeown et al[43], 2008	Automatic	Shape	Locally reduction of the dorsal surface of bilateral thalamus
	Garg et al[20], 2015	Automatic	Shape	Net-inward and outward deformation of left thalamus
Hippocampus
	Wang et al[55] , 2018	Automatic	Volume	Reduced volume of right hippocampus
	Chen et al[56], 2016	Automatic	Density	Reduced density of left hippocampus
	Geevarghese et al[15], 2015	Automatic	Volume	Reduced volume of left hippocampus (with cognition)
	Lee et al[14], 2014; Tanner et al[16], 2017; Radziunas et al[53], 2018; Melzer et al[30], 2012	Automatic	Volume	Reduced volume of bilateral hippocampus
	Vasconcellos et al[17], 2018	Automatic	Volume	Reduced volume of bilateral hippocampus (with disease duration)
	Camlidag et al[68], 2014; Xu et al[59], 2020	Automatic	Volume	Reduced volume of bilateral hippocampus (with cognition)
	van Mierlo et al[64], 2015	Automatic	Volume	Reduced volume of bilateral hippocampus (with depression)
	Rahayel[63], 2019	Automatic	Volume	Reduced volume of bilateral hippocampus (with REM-RBD)
	Wilson et al[54], 2019	Automatic	Volume	Reduced volume of bilateral hippocampus (with cognition, motor and disease duration)
	Luo et al[60], 2021	Automatic	Volume	Reduced volume of subfields (with cognition)
	Uribe et al[61], 2018	Automatic	Volume	Reduced volume of subfields, especially CA1
	Becker et al[62], 2021	Automatic	Volume	Reduced volume of CA1 (with cognition)
	Xu et al[59], 2020	Automatic	Volume	Reduced volume of subiculum, CA2/3, CA4, ML and right GC-DG
	Park et al[57], 2019	Automatic	Volume	Volume asymmetry, especially in CA4-DG and CA2-3
	Tanner et al[16], 2017	Automatic	Shape	Locally reduction in the head and CA1 bilaterally
	Devignes et al[28], 2021	Automatic	Shape	Locally reduction of right hippocampus (with cognition)

REM: Rapid eye movement; RBD: Sleep behavior disorder; STN: Subthalamic nucleus; CA: Cornu ammonis (subfields of hippocampus); ML: Molecular layer subfields; GC-DG: Granule cell layer of the dentate gyrus.