Viljami Sairanen

Viljami Sairanen
Kanta-Häme Central Hospital, Finland

PhD
Full-time clinical work with part-time research related to robust-to-motion estimators for diffusion MRI models.

About

23
Publications
2,708
Reads
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141
Citations
Citations since 2017
17 Research Items
128 Citations
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Introduction
Besides my clinical work with MRI and other medical imaging modalities, I do part-time research on robust modelling and statistical methods for medical image and signal analyses.
Additional affiliations
May 2021 - present
University of Helsinki
Position
  • Senior Researcher
May 2020 - April 2021
University of Verona
Position
  • PostDoc Position
January 2017 - present
Helsinki University Central Hospital
Position
  • Medical Professional

Publications

Publications (23)
Article
Full-text available
Infants are well known to seek eye contact, and they prefer to fixate on developmentally meaningful objects, such as the human face. It is also known, that visual abilities are important for the developmental cascades of cognition from later infancy to childhood. It is less understood, however, whether newborn visual abilities relate to later cogni...
Article
Full-text available
Learning and speaking a second language (L2) may result in profound changes in the human brain. Here, we investigated local structural differences along two language-related white matter trajectories, the arcuate fasciculus and the inferior fronto-occipital fasciculus (IFOF), between early simultaneous bilinguals and late sequential bilinguals. We...
Article
Full-text available
In healthy subjects, motor cortex activity and electromyographic (EMG) signals from contracting contralateral muscle show coherence in the beta (15-30 Hz) range. Corticomuscular coherence (CMC) is considered a sign of functional coupling between muscle and brain. Based on prior studies, CMC is altered in stroke, but functional significance of this...
Article
Full-text available
The white matter structures of the human brain can be represented using diffusion-weighted MRI tractography. Unfortunately, tractography is prone to find false-positive streamlines causing a severe decline in its specificity and limiting its feasibility in accurate structural brain connectivity analyses. Filtering algorithms have been proposed to r...
Article
Full-text available
The segmentation of brain structures is a key component of many neuroimaging studies. Consistent anatomical definitions are crucial to ensure consensus on the position and shape of brain structures, but segmentations are prone to variation in their interpretation and execution. White‐matter (WM) pathways are global structures of the brain defined b...
Preprint
Full-text available
The white matter structures of the human brain can be represented using diffusion-weighted MRI tractography. Unfortunately, tractography is prone to find false-positive streamlines causing a severe decline in its specificity and limiting its feasibility in accurate structural brain connectivity analyses. Filtering algorithms have been proposed to r...
Conference Paper
Full-text available
The white matter structures of the human brain can be represented via diffusion tractography. Unfortunately, tractography is prone to find false-positive streamlines causing a severe decline in its specificity and limiting its clinical feasibility. Filtering algorithms have been proposed to reduce these invalid streamlines. We augmented the COMMIT...
Conference Paper
Full-text available
Diffusion MRI measurements are affected by noise which propagates into the model estimation. Residual bootstrapping has been proposed to assess the uncertainty of parameter estimates, but do not consider the confounding effect of measurement outliers (e.g. due to subject motion), limiting their usage on clinical data. We present a robust bootstrapp...
Conference Paper
Full-text available
Diffusion-weighted magnetic resonance imaging tractography is used to represent brain structures but it has limited specificity. Tractogram filtering is proposed to fix this by utilizing e.g. microstructural information to find which streamlines are essential in respect to the original measurements. However, filtered results can be biased if the me...
Article
Full-text available
Aspartylglucosaminuria (AGU) is a rare lysosomal storage disorder causing developmental delay, intellectual disability, and eventual death. A distinct feature in AGU is iron accumulation within the thalamus. Our aim is to demonstrate that susceptibility-weighted images (SWI) could be used as an MRI biomarker to evaluate the response within the AGU...
Conference Paper
Full-text available
We report an original finding of a strong linear correlation (F=26, p=1.5e-4, R =0.65) between iron accumulation within specific thalamic structures and the age of children with aspartylglucosaminuria (AGU). AGU is a rare lysosomal storage disorder which has no cure, causes a negative effect on the development of a child, and leads to a premature d...
Conference Paper
Full-text available
Diffusion-and kurtosis tensor estimators generally assume independent and a Gaussian distributed noise. While with adequate signal-to-noise ratios (SNR) this assumption can be made without significant bias in the estimated models, this is not true when utilizing high diffusion weighting thus low SNR. In such case, the Rician noise should be conside...
Conference Paper
Full-text available
Characterizing uncertainty distributions in diffusion MRI derived metrics such as fractional anisotropy or kurtosis anisotropy requires non-parametric approaches, since the correct form of the distribution is rarely known a priori. Previously suggested wild bootstrapping methods, however, have not considered the impact of outliers in the data. In t...
Conference Paper
Full-text available
The accurate characterization of diffusion process with MRI is compromised by various artefacts including intensity related errors. If not appropriately accounted for, model estimates can become significantly biased resulting in erroneous metrics. Slicewise intensity errors, in particular, are often handled by excluding the entire image or slice in...
Article
Full-text available
Despite numerous functional neuroimaging and intraoperative electrical cortical mapping studies aimed at investigating the cortical organisation of native (L1) and second (L2) language processing, the neural underpinnings of bilingualism remain elusive. We investigated whether the neural network engaged in speech production over the bilateral poste...
Article
Objective To compare methods of estimating spike strength as a potential index in the assessment of continuous spikes and waves during sleep (CSWS). Methods Spikes were searched and averaged automatically from pre- and postoperative EEGs of ten patients with CSWS who underwent corpus callosotomy (eight) or resective epilepsy surgery (two). From th...

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Projects

Project (1)
Project
I'm developing a Python based pipeline for clinical diffusion weighted MRI data that accounts for slice-wise outliers in signal drift, subject motion, eddy currents and EPI artefact corrections. Tools will be designed so that they can be used in parallel with ExploreDTI, Dipy, FSL, and MRtrix3 at least.