Freesurfer March 2021

freesurfer@nmr.mgh.harvard.edu

106 participants
144 discussions

Unit of the Numbers in cache.th40.neg.y.ocn.dat
by Na, Xiaoxu 17 Feb '24

17 Feb '24

External Email - Use Caution Dear Freesurfer Experts, As I'd like to extract the average value of each subject in the cluster after running group analysis, may I know the unit of these numbers? Since the one I'm running is surface area, and the cluster is 444mm^2, all the numbers in the file cache.th40.neg.y.ocn.dat is in the range of [0.55 1.05], may I know if this is correct and if so, how the unit is for those? Thanks a lot! ClusterNo Max VtxMax Size(mm^2) MNIX MNIY MNIZ CWP CWPLow CWPHi NVtxs WghtVtx 1 -4.8321 40067 444.11 -58.1 -16.6 -23.9 0.0002 0 0.0004 670 -2784.11 Regards, Xiaoxu ---------------------------------------------------------------------- Confidentiality Notice: This e-mail message, including any attachments, is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies of the original message.

4 11

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

Reliability and sensitivity of two whole-brain segmentation approaches − ASEG and SAMSEG
by Donatas Sederevicius 28 Aug '22

28 Aug '22

External Email - Use Caution A new pre-print paper comparing two FreeSurfer’s whole-brain segmentation methods - ASEG and SAMSEG is now available (see the link below). The study is of great interest to many researchers in the field, providing new insights and guiding the selection of the processing method. https://www.biorxiv.org/content/10.1101/2020.10.13.335737v1

3 3

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

Sulcal probability maps
by Kristi Drudik 12 May '21

12 May '21

External Email - Use Caution Good afternoon, I hope this email finds you well. I am in the process of "painting" MRI surfaces from the Human connectome project in FreeSurfer, meaning creating labels on the surfaces to analyze sulcal morphology. We are interested in the spatial variability of the sulcus and thus, want to create surface spatial probability maps using FreeSurfer (please see attachment for an example of such surface probability maps). These maps would represent the likelihood of each vertex on the FreeSurfer fsaverage surface belonging to the sulcus of interest (from 0% to 100%). To obtain these probability maps, I: * Painted the sulcus of interest on the surface by creating a .label file. * Registered this .label file to fsaverage (mri_label2label) * Converted the .label file to vol (mri_label2vol) * Converted it to a surface file (mri_vol2surf) * Concatenated the data to create an average (mri_concat --mean) * Blurred the data and loaded the blurred average as an overlay onto the fsaverage pial (mris_fwhm) Because this seems very convoluted, my question becomes: Is there a more direct way to generate these maps from the labels themselves, rather than going from label to vol, then back to surf? Finally, I would like these maps to represent a 0-100% range of each vertex in fsaverage belonging to the sulcus of interest. However, this method creates a 0-1 range (please see colour bar in attachment). Is there a way to change this to a percentage? Thank you very much for your time and help. Please let me know if you have any questions. Best, Kristi Kristi Drudik Ph.D. Student, Clinical Psychology Montreal Neurological Institute McGill University Montreal, Canada

3 20

Cortical surface analysis
by Ornaith O Reilly 10 May '21

10 May '21

External Email - Use Caution Hello Freesurfer developers, I am new to Freesurfer and I'm hoping that someone can help me. My goal is to be able to visualise electrodes contacts that are on lying on the cortical surface on a flat map and a spherical map. I've run recon-all and created the flatmap. I'm using Matlab to achieve this and I've loaded the information with the lines lhsphere = fs_read_surf( '/Applications/freesurfer/7.1.1/subjects/IM-0001/surf/lh.sphere'); lhflatpatch=fs_read_patch( '/Applications/freesurfer/7.1.1/subjects/IM-0001/surf/lh.full.flat.patch.3D' ); 1. I want to be able to access the coordinates and show the electrons on the flat map/ sphere and I was wondering how to do this? I understand that the vertex ID number is what relates the coordinates in the original image to these surfaces. I am wondering how to access the vertex ID numbers ? At the moment I think that I only have access to the vertex coordinates and the vertex faces. 2. Additionally, I was wondering if there is a way to display the surface images through Matlab? What would be the best way to show the surface with the electrons overlaid on it? The version of Freesurfer and the platform that I'm using is outlined below: 1) FreeSurfer version: freesurfer-darwin-macOS-7.1.1-20200811-8b40551 2) Platform: macOS High Sierra 10.13.6 (17G7024) I really appreciate any help with this as I'm really stuck. Thanks in advance for any help. Kind Regards, Ornaith O'Reilly

3 10

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

make_average_subject without Talairach transform
by Trisanna Sprung-Much 05 May '21

05 May '21

External Email - Use Caution Hi there I’d like to know if it is possible to create an average volume and average surface of several subjects without having to incorporate the Talairach transform and no transform at all. Thank you, Trisanna Sprung-Much Research Associate McGill University MD Anderson Cancer Centre --

3 10

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

Abormally high foldind index
by Ellen Ji 19 Apr '21

19 Apr '21

External Email - Use Caution Dear Experts, While the majority of our subjects have a folding index between 5-30, there are a couple of *extreme* outliers in the thousands or even negative. Could this hint that a particular part of recon-all failed and should be rerun? Thank you for your interpretation and advice! -Ellen

2 3

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 March 2021