Freesurfer August 2020

freesurfer@nmr.mgh.harvard.edu

101 participants
152 discussions

Extract single time frame
by Rockers, Elijah D. 16 Oct '22

16 Oct '22

Hello again, I have a large time series in dicom or .nii format. I am interested in extracting a single time frame from it. I did this before, I believe with freesurfer, but I have somehow forgot the name of the command, and I can't seem to find it. I believe it could be used to specify particular regions of the volume, as well as time. I need the entire volume, still, but only one frame. Thanks in advance! Eli Houston Methodist. Leading Medicine. Ranked by U.S.News & World Report as one of America's "Best Hospitals" in 11 specialties. Named to FORTUNE® Magazine's "100 Best Companies to Work For®" list 10 years in a row. Designated as a Magnet hospital for excellence in nursing. Visit us at houstonmethodist.org. Follow us at twitter.com/MethodistHosp and www.facebook.com/HoustonMethodist. ***CONFIDENTIALITY NOTICE*** This e-mail is the property of Houston Methodist Hospital and/or its relevant affiliates and may contain restricted and privileged material for the sole use of the intended recipient(s). Any review, use, distribution or disclosure by others is strictly prohibited. If you are not the intended recipient (or authorized to receive for the recipient), please contact the sender and delete all copies of the message. Thank you.

4 4

Postdoctoral position: Neuroimaging, PCAN lab, University of Calgary, Canada, 2 years
by Alexandru Hanganu 16 Jun '21

16 Jun '21

External Email - Use Caution Dear All, The PCAN lab: http://pcanlab.ca has a two-year funded postdoctoral research fellow position under the supervision of Dr. Oury Monchi starting immediately to work on the following project: *Neuroimaging and other predictors of cognitive and neuropsychiatric evolution in Parkinson’s disease using multi-modal MRI imaging techniques and machine learning.* The project is funded by the Canadian Institutes of Health Research (CIHR) . It involves longitudinal analyses of cortical thickness, tractography and BOLD resting-state fMRI analyses and will benefit from collaborations with Dr. Alexandru Hanganu at the Department of Psychology of the University of Montreal. Other collaborators include Dr. Nils Forkert head of the Medical Imaging Processing and Machine Learning laboratory. A special focus will be given to the neural origins and predictors of Mild Behavior Impairment (MBI) in Parkinson’s disease in collaboration with Dr. Zahinoor Ismail who has led the development of the MBI-checklist. The project will make use of an existing longitudinal study containing structural, diffusion weighted imaging and functional MRI, neuropsychological and behavioural assessment, and genotyping at three time points. The PCAN lab has been a pioneer in using different neuroimaging techniques to study the origins and evolution of cognitive more recently neuropsychiatric deficits in Parkinson’s disease with the ultimate goal of early prediction of dementia in the disease. Other interests include the function and application of neuromodulation techniques such as transcranial magnetic stimulation, Transcranial direct stimulation and low intensity focused ultrasound. The PCAN Lab is located in the Healthy Brain Aging labs of the Hotchkiss Brain Institute part the Foothills Campus of the University of Calgary. The Foothills campus is home to the Seaman Family MR Research Centre which host a General Electric 3T research dedicated MRI scanner. Requirements of the position include a PhD in Neuroscience, biomedical engineering, biomedical sciences, or Psychology with experience in the analysis of one or multiple MRI neuroimaging techniques such as cortical thickness/volumetry (e.g. *Freesurfer, FSL*), functional connectivity (e.g. *PPI, ICA, graph theory*), diffusion weighted imaging (e.g. *Dipy, MRTrix, FSL*). Some fluency in computer programming (e.g. *Linux, Unix, MATLAB, or Python)* is also required as well as the ability to write scientific peer-reviewed manuscripts. Please send applications (Cover letter, CV, and the name of 2 references including current supervisor) to Oury Monchi: oury.monchi(a)ucalgary.ca

1 1

Job ad: MRI physicist
by Keith Schneider 07 May '21

07 May '21

External Email - Use Caution The Center for Biomedical and Brain Imaging (CBBI) is a core imaging facility at the University of Delaware dedicated to scientific research. It is equipped with a Siemens Prisma 3T MRI scanner, Bruker 9.4T small bore MRI scanner, TMS, and MRI-compatible EEG. It supports a wide range of scientific investigations through imaging of humans, animals and materials. Under general direction of the CBBI Manager, the MRI Physicist is responsible for supporting the operations of the Siemens and Bruker MRI scanners. The MRI Physicist is expected to contribute to both research and training efforts that will include pulse sequence programming, parameter and image quality optimization, protocol design, scanner operation, technical support and user training. The candidate will be expected to maintain a broad knowledge of state-of-the-art MRI technology and equipment. The incumbent must have excellent communication and organizational skills, the ability to positively interact with a diverse group of MRI users, and a strong motivation to learn new MRI techniques. MAJOR RESPONSIBILITIES: • Pulse sequence programming on Bruker 9.4T and Siemens 3T MRI scanners • Assist users on appropriate choice and use of coils • Technical liaison for obtaining sequences or protocols for non-standard imaging (e.g. cardiac, musculoskeletal) from Siemens and other sites • File reports as needed for WIP sequences and Siemens MRA • Ensure data quality from the viewpoint of machine fundamentals • Technical support 9.4T and 3T scanners • Protocol design and testing for 9.4T scanner, including imaging of live animals and awake animals; as-needed for 3T • Routine quality assurance for 9.4T and 3T MRI scanners • Train users, including students, on use of 9.4T and 3T MRI scanners • Help users optimize pulse sequence parameters to maximize SNR and avoid imaging artifacts • Consult on image analysis, as needed • Review journals and abstracts to keep abreast of new developments • Collaborate with ongoing research as needed; may have independent research projects if desired • Consult users about imaging details for manuscript preparation and grant applications, as needed • Perform miscellaneous job-related duties as assigned QUALIFICATIONS: • PhD in MR physics or MS with equivalent experience • expert understanding of MR physics, image acquisition, signal processing, imaging processing and image reconstruction • MR pulse sequence programming • Experience with Bruker and Siemens MRI scanners • MRI scanning experience with both humans and animals—willing to handle animals • Ability to design experiments, optimize MRI protocols, troubleshoot image artifacts, analyze data, and interpret results • Knowledge of functional MRI, DTI, MRS, T1/T2 relaxation and perfusion • Siemens IDEA and ICE certification (or ability to obtain) http://careers.udel.edu/cw/en-us/job/493998/mri-physicist-research-office <http://careers.udel.edu/cw/en-us/job/493998/mri-physicist-research-office> For further information, contact me. keith ----- Keith Schneider Director, Center for Biomedical and Brain Imaging Associate Professor Department of Psychological and Brain Sciences University of Delaware

1 1

Parcellation Error Pre-Post Central Gyrus R but not L Hemisphere
by Fraser Smith 26 Apr '21

26 Apr '21

External Email - Use Caution Hi there I have a clear parcellation error with one participant who does look to have an atypical structure around the right post-central gyrus (looks split in two). Both the pre and post central gyri are shifted significantly backwards – but only for the right not the left hemisphere. I see this has been mentioned before in the archives – but I have been unable to find a fix for this. Could you provide any tips on what to try? I am using v6.0.0. Best wishes Fraser Smith

3 3

label to surface
by Sam W 02 Feb '21

02 Feb '21

External Email - Use Caution Hi, Is there a way to convert a label file into a surface/overlay? Thank you! Best regards, Sam

3 9

Correct for sulcuses & ventricles size
by John Anderson 13 Dec '20

13 Dec '20

External Email - Use Caution Dear Freesurfer experts, I have two groups of subjects (healthy and patients). The patients have different degrees of atrophy. Looking into the individual scans, the subjects are largely different in the space between the sulcuses and the size of ventricles. My questions are: 1. Is there any way to correct for these differences in the surface based analysis? 2. Including eTIV covariate does it help in this case? 3. Does the resampling to "fsaverage" overcome the challenge of these differences between the subjects? I appreciate any advice, John

3 5

peak MNI coordinates within a masked sig.mgh
by Fred Sampedro 18 Sep '20

18 Sep '20

External Email - Use Caution Dear FS experts, I have a rather simple question: I would like to obtain the MNI coordinates of the most significant vertex in a sig.mgh map but within a specific ROI (for instance the left supramarginal region). Here is my attempt but with practical gaps in terms of command parameters: 1) mri_binarize lh aparc --min LABEL/NUMBER_OF_SUPRAMARG? --o roimask.mgh 2) fslmaths sig.mgh mult roimask.mgh -o maskedsig.mgh 3) which command could I use to obtain the MNI coordinates of the peak value in maskedsig.mgh? Thanks a lot in advance!

3 8

Config File For Tracula Question
by Ledesma, Jason 17 Sep '20

17 Sep '20

External Email - Use Caution Hi, See attached for my Configfile for Tracula. See attached. What might be the issue with this? Sincerely, Jason Ledesma Staff Research Associate Phone: 1(424)571-7755 E-mail: jason.ledesma(a)lundquist.org ___________________________________________________________________________________ LUNDQUIST Institute Warning: This email (and any attachments) is intended for the use of the person to which it is addressed. It may contain information that is privileged and confidential. As the recipient, you are obligated to maintain it in a safe, secure and confidential manner. Unauthorized disclosure or failure to maintain confidentiality may subject you to governmental penalties. Should you not be the intended recipient, please notify us by return email, and delete this message from your computer at once. ___________________________________________________________________________________

2 3

Asymmetry whole thalamus with native vs Iglesias method
by Chris Vriend 11 Sep '20

11 Sep '20

External Email - Use Caution Dear freesurfer experts, I’m currently using FreeSurfer 7.1 with the thalamus subsegmentation from Iglesias et al (version 12) to subsegment the thalamus. Something we noticed is that the asymmetry between the left and right whole thalamus is reversed when comparing the native thalamus segmentation by FreeSurfer itself and the Iglesias method. This is exemplified by the values below where we calculated the Asymmetry Index [ (Left – right)/(left + right) * 100 ] and shows that for some subjects the left thalamus is larger when looking at the results of the Iglesias method, but smaller with the native method. To allow comparison between the two methods we subtracted the LGN and MGN volumes from the whole thalamus volume, because – if I’m not mistaken – these nuclei are not segmented by the standard recon-all pipeline? We don’t know why we observe this and not just in one dataset or one subject but in multiple. Do you have any words of wisdom or explanation for this phenomenon? Your advice is much appreciated. Kind regards, Chris Vriend Whole_thalamus_lh_Iglesias whole_thalamus_rh_Iglesias AI Fsnative_Left-Thal Fsnative_Right-Thal AI 4913.391 5129.889 -2.155650345 5987.2 5764.6 1.894177913 6019.185 6235.017 -1.761289719 6793.9 6732.4 0.454669791 6374.575 6574.893 -1.546920692 7543.9 7592.1 -0.318446089 6974.051 6983.314 -0.066366395 7661.3 7624.8 0.238779021 5907.853 5798.037 0.93812602 6756.4 6485.2 2.048090865 6316.792 6382.639 -0.518503546 7191.2 6959.7 1.63593835

3 8

mri_vol2vol with --inv-morph producing unexpected results
by Noriana Jakopin 09 Sep '20

09 Sep '20

External Email - Use Caution Hello FreeSurfer Developers, I am attempting to use the inverse of the final m3z registration file produced by mri_cvs_register to take files in mni152 space back into my subject's space. I used mri_vol2vol with the --inv-morph flag to accomplish this. However, the resulting outputs produce images with abnormal warpings to the brain. Using mri_vol2vol to take subject files into mni152 space with the same m3z file works fine, it seems to be the inverse that is the problem. Does anyone have thoughts on how I can remedy this issue? FreeSurfer Version: freesurfer-linux-centos6_x86_64-7.1.1 Platform: Windows Subsystem for Linux - Ubuntu 18.04 LTS Thank you! Noriana Jakopin

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 August 2020