Freesurfer

freesurfer@nmr.mgh.harvard.edu

17 participants
30130 discussions

questions about mri_normalize
by John Anderson 27 Apr '23

27 Apr '23

External Email - Use Caution Dear experts, I have been using the mri_normalize in FSv7.3.2 to standardize the intensity of FLAIR images , and I've observed that increasing the sigma parameter up to 25 is effective in improving the quality of the normalized images for noisy datasets. mri_normalize -sigma 25 -g 1 FLAIR_skullstripped.nii FLAIR_skullstripped_norm.mgz However, I have questions about the n argument, which is set to 2 by default. For noisy images, white matter intensity after normalization is around 140-150. When using n=10, I noticed that the white matter intensity decreased from 140-150 to around 110-120, resulting in better quality normalized images. 1) I'm wondering if there is a cut-off value for the number of iterations, or if a higher number of iterations always yields better results. 2) Also, if the intensity of the white matter after normalization is not around 110, but instead around 140 or 150, does that indicate that the normalization was not effective and that we need to increase the number of iterations? Thank you for your assistance. John

1 1

Re: [Freesurfer] EasyReg for group-average template?
by AmirHussein Abdolalizadeh 27 Apr '23

27 Apr '23

External Email - Use Caution Hi Eugenio, Thanks for your reply. Just to check if I've understood correctly, these can be the steps by using mri_easyreg: *Linear (with --affine-only):* 1. Register all the subjects to the MNI (subj_to_MNI_lin_1) 2. Average the subj_to_MNI_lin_1s to reach a new template (MNI_mod_lin_1) 3. Register subj_to_MNI_lin_1s to MNI_mod_lin_1 and achieve subj_to_MNI_lin_2 and MNI_mod_lin_2 (and repeat it 5-6 times) *NonLinear:* 1. Register subj_to_MNI_lin_5s to MNI_mod_lin_5 nonlinearly to achieve subj_to_MNI_nlin_1 and MNI_modified_nlin_1. 2. Repeat the steps similarly 5 times. Correct? I also have another question: Should I do the linear-nonlinear in an interleaved manner or first linear registrations iterations and then non-linear? Best, Amir

1 0

Does Incorporating T2 into recon-all impact ICV and local morphometric estimates?
by Steven Meisler 26 Apr '23

26 Apr '23

External Email - Use Caution Hi FS team, I am running a morphometry study on a public dataset with most, but not all, subjects having a T1 and T2 (about 75% have both, remaining only have T1). To get the best surfaces possible, I have been including the T2 in recon-all process when able to. However, this means subjects with only a T1 have underwent a different processing workflow. ICV is an important predictor in my study, and I was wondering if the presence of the T2 image in recon-all should impact the ICV estimates? As I see it, I have the following options: 1) T2 is a factor, so I use only include T1 in recon-all so all subjects have the same pipeline 2) T2 is a factor, so I harmonize the data as I would with data from different sites/scanners 3) T2 is a factor, so I only analyze subjects with T1 + T2 4) T2 is not a factor, just use all subjects with no special considerations I am also running vertex-wise surface based morphometry, where I imagine pial refinements could be more impactful. I suppose in that case, I should harmonize the morphometry data, but was curious if you think something like that is necessary. Thank you, Steven Meisler

2 1

FSFAST: multiple resting state runs
by Elmira Hassanzadeh 26 Apr '23

26 Apr '23

External Email - Use Caution Hi, How do we analyze multiple resting state runs for a subject at once? - do we need certain folder structure/naming? - do we do concatenation? Thanks, Elmira

2 2

Neuroimaging Postdoctoral Fellowship Position: Bronte-Stewart Lab at Stanford University
by Kevin Bryant Wilkins 26 Apr '23

26 Apr '23

External Email - Use Caution The Human Motor Control and Neuromodulation Lab under Dr. Helen Bronte-Stewart (https://secure-web.cisco.com/1--QzHnbqbSp-JZkXqnRQUXC9NwJSM-Wjso7zaYuabDXqn…) part of the Stanford Movement disorders Center within the Department of Neurology and Neurological Sciences at Stanford University’s School of Medicine, is seeking a postdoctoral scholar with neuroimaging expertise to investigate cognitive-motor dysfunction in Parkinson’s disease. The current position is for a project where we will be conducting a pilot clinical trial using a novel deep brain stimulation approach for cognitive and cognitive-motor dysfunction in Parkinson’s disease. The candidate will help validate the use of a novel target for deep brain stimulation using a combination of tractography and DBS modeling (e.g., volume of tissue activated). You will work together with neurosurgeons, radiologists, and neurologists on the trial to validate various trajectories and targets. You will work with stimulation modeling software to individualize stimulation parameters for participants to optimize efficacy. In addition to your role on this project, you will get the chance to investigate structural differences in brain morphology between different neurodegenerative diseases. The current position offers an exceptional opportunity for neuroscientists with a background in structural neuroimaging and/or cognition to apply these skills in a clinically-relevant domain. The desired candidate would have a PhD in Neuroscience or a related discipline with experience in neuroimaging, cognition, and motor control. Preferred start date is before September 2023 but is flexible. Job Requirements Required: PhD in Neuroscience or related disciplines with expertise in data science Experience in structural neuroimaging (tractography, voxel-based morphometry, etc.) Experience working in the area of cognition and motor control Comfortable analyzing data in Matlab, Python, or similar languages Strong data science skills Ability to work well in a diverse team Effective oral and written communication skills Excellent organization skills and demonstrated ability to complete detailed work accurately Excellent problem-solving ability Preferred: Experience with Parkinson’s disease or other clinical populations Experience with deep brain stimulation modeling (volumes of tissue activated, etc.) Experience with larger data sets How to Apply: Apply by sending the following to Kevin Wilkins (wilkins2(a)stanford.edu) CV Cover letter describing interest and relevant experience for the project Three potential reference contacts (We will not contact references until confirming with you) The expected base pay for this position is the Stanford University required minimum for all postdoctoral scholars appointed through the Office of Postdoctoral Affairs. The FY23 minimum is $68,238. Stanford University is an affirmative action and equal opportunity employer, committed to increasing the diversity of its workforce. It welcomes applications from women, members of minority groups, veterans, persons with disabilities, and others who would bring additional dimensions to the university's research and teaching mission

1 0

The longitudinal Midlife in the U.S. (MIDUS) study is looking for postdoctoral researchers
by STACEY M SCHAEFER 26 Apr '23

26 Apr '23

External Email - Use Caution The MIDUS Affective Neuroscience Project team led by Dr. Stacey M. Schaefer at the University of Wisconsin-Madison’s Institute on Aging is seeking a postdoctoral scholar to analyze and publish on data from the national longitudinal Midlife in the US study. MIDUS is an NIA-supported study on aging explicitly focused on all the adult years (25-100+) with multiple longitudinal timepoints over the past +20 years. This is an opportunity to become part of a scientific community that is actively engaged with MIDUS and play a key role in analyzing neuroimaging data in relation to affective, psychophysiological, sociodemographic, behavioral, cognitive, biomarker, and environmental data with an emphasis on understanding the factors that are important for emotional wellbeing, brain health, and brain aging. For more information see: https://secure-web.cisco.com/191EwmVOBKe0a4n05j11zWFZF5tHg3ATL6HmuGKmYAjsUQ… Stacey M. Schaefer, Ph.D. Leader of the MIDUS Neuroscience Project & Co-Leader of the MIDUS Admin Core Institute on Aging 2245C Medical Sciences Center University of Wisconsin-Madison 1300 University Ave Madison, WI 53706 USA

1 0

Freesurfer 7.2.0 release in Ubuntu 18d .ova.7z password
by Min Wang 26 Apr '23

26 Apr '23

External Email - Use Caution Greetings team Freesurfer, Following the instructions in your wiki page, I’m sending you to kindly provide me with the .7z password for the said file (Freesurfer 7.2.0 release in Ubuntu 18.04.06: FS_7_2_0_Ubuntu_18_04_06.ova.7z). Thanks a lot in advance, Min Wang

1 0

EasyReg for group-average template?
by AmirHussein Abdolalizadeh 26 Apr '23

26 Apr '23

External Email - Use Caution Dear Freesurfer users/experts, I am working on a research project that requires generating group-average templates from a large sample of data. I wonder about the possibility of using mri_easyreg for generating group-average templates. To my knowledge, the best current pipeline is based on using ANTs that 1) do not support GPU, 2) take ages to generate a template esp. from a large sample of data. I wanted to know, do you have any suggestions to use mri_easyreg for such purposes? I would greatly appreciate any suggestions or advice you can provide. Best, Amir

2 1

Alternatives to Qdec
by 余卓远 26 Apr '23

26 Apr '23

External Email - Use Caution Dear experts, I was trying to use the Qdec script that came with Freesurfer to perform intergroup analysis of morphological data such as cortical surface area, but I found that the Qdec tool has been removed in version 7.2. Is there an alternative that can do the analysis as described above in version 7.2? Or should I download the previous version software? Kind regards, Zhuoyuan

2 1

passcode to install freesurfer
by ANAIS LLORENS 25 Apr '23

25 Apr '23

External Email - Use Caution Hi I woud like the pass code to open FS_7_2_0_Ubuntu_18_04_06.ova.7z. Thank you! Anais

2 2

Jump to page:

2026

2025

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

Freesurfer