Julien Cohen-Adad

Pierre Louis Benveniste

PhD - Polytechnique Montréal

Co-supervisor :

PhD - Polytechnique Montréal

Thomas Dagonneau

Master's Research - Polytechnique Montréal

Naga Karthik Enamundram

PhD - Polytechnique Montréal

Co-supervisor :

Master's Research - Polytechnique Montréal

Youssef Laatar

Master's Research - Polytechnique Montréal

Julien Laborde-Peyré

Research Intern - Polytechnique Montréal

Nilser Laines Medina

PhD - Polytechnique Montréal

Nathan Molinier

PhD - Polytechnique Montréal

Collaborating researcher

Arthur Toulouse

Master's Research - Polytechnique Montréal

Publications

Automated robust segmentation of the spinal canal on MRI

Abel Salmona

Sandrine Bédard

Maxime Bouthillier

Gergely David

Maryam Seif

Armin Curt

Nikolai Pfender

Markus Hupp

Patrick Freund

Tomáš Horák

Petr Kudlička

Josef Bednařík

Fauziyya Muhammad

Zachary A. Smith

2026-05-31

European Journal of Radiology Artificial Intelligence (published)

Spatial distribution of spinal cord fMRI activity with electrocutaneous stimulation

Sandrine Bédard

Merve Kaptan

Teresa Indriolo

Dario Pfyffer

Lindsay Lee

John K Ratliff

Serena S. Hu

Suzanne Tharin

Zachary A. Smith

GARY GLOVER

Sean C Mackey

Kenneth A. Weber

Christine SW Law

Sensory organization at the spinal segment level is commonly inferred from dermatomal maps that assume a fixed correspondence between cutane… (see more)ous regions and spinal segments. However, based on the complexities of spinal neuroanatomy and neurophysiology, the distribution of sensory signals within the cord may be broader and less segment-specific than dermatomal maps suggest, leaving the segment-level localization of sensory-evoked activity in humans uncertain. Spinal cord functional magnetic resonance imaging (fMRI) is currently the only technique capable of noninvasively mapping sensory activity with high spatial resolution in the human spinal cord. However, its application remains technically challenging and is limited by the uncertainty in segmental localization. In this study, we leveraged recent advancements in spinal cord fMRI, including spinal nerve rootlet-based spatial normalization, to investigate how sensory information is represented and distributed within the human spinal cord during electrocutaneous stimulation of the third digit of the right hand (i.e., C7 dermatome). Forty healthy adults were scanned with electrocutaneous stimulation at four individualized intensities across multiple runs to quantify (i) the rostrocaudal distribution of sensory-evoked activity, (ii) intensity-dependent changes in detectability and localization, and (iii) the effect of normalization strategy on segmental localization. Across participants, stimulation produced activation localized in the lower cervical cord (e.g., C6-C8), with the most consistent segmental localization near C7. Stronger stimulation increased detectability and produced more consistent segmental localization across participants. Importantly, normalization that incorporated nerve rootlet landmarks sharpened localization and improved sensitivity relative to conventional intervertebral disc-based alignment. This highlights the value of functionally relevant anatomical landmarks for group inference in the spinal cord. Responses were strongest in the initial run and attenuated with repetition, suggesting habituation or adaptation that can bias multi-run paradigms if unmodeled. Together, our results define practical acquisition and analysis conditions (e.g., stimulation strength, anatomical alignment strategy, and run structure) under which segment-level spinal sensory responses can be detected, thereby supporting more reliable studies of human spinal cord future basic and translational studies, including pain mechanisms, sensory function, and spinal injury.

2026-03-01

medRxiv (preprint)

Monitoring morphometric drift in lifelong learning segmentation of the spinal cord.

Enamundram Naga Karthik

Sandrine Bédard

Christoph Stefan Aigner

Elise Bannier

Josef Bednařík

Virginie Callot

Anna Combes

Armin Curt

Gergely David

Falk Eippert

Lynn Farner

Michael G. Fehlings

Patrick Freund

Tobias Granberg

Cristina Granziera

Rhscir Network Imaging Group

Ulrike Horn

Tomáš Horák

Suzanne Humphreys … (see 36 more)

Markus Hupp

Anne Kerbrat

Nawal Kinany

Shannon Kolind

Petr Kudlička

Anna Lebret

Lisa Eunyoung Lee

Cristina Granziera

Allan R. Martin

Govind Nair

Megan McGrath

Kristin P. O’Grady

Jiwon Oh

Russell Ouellette

Nikolai Pfender

Dario Pfyffer

Pierre‐François Pradat

Alexandre Prat

Daniel S. Reich

Ilaria Ricchi

Naama Rotem‐Kohavi

Simon Schading-Sassenhausen

Maryam Seif

Andrew Smith

Seth A. Smith

Grace Sweeney

Roger Tam

Anthony Traboulsee

Constantina A. Treaba

Charidimos Tsagkas

Dimitri Van De Ville

Zachary Vavasour

Kenneth A. Weber

Sarath Chandar

Morphometric measures derived from spinal cord segmentations can serve as diagnostic and prognostic biomarkers in neurological diseases and … (see more)injuries affecting the spinal cord. For instance, the spinal cord cross-sectional area can be used to monitor cord atrophy in multiple sclerosis and to characterize compression in degenerative cervical myelopathy. While robust, automatic segmentation methods to a wide variety of contrasts and pathologies have been developed over the past few years, whether their predictions are stable as the model is updated using new datasets has not been assessed. This is particularly important for deriving normative values from healthy participants. In this study, we present a spinal cord segmentation model trained on a multisite (n=75) dataset, including 9 different MRI contrasts and several spinal cord pathologies. We also introduce a lifelong learning framework to automatically monitor the morphometric drift as the model is updated using additional datasets. The framework is triggered by an automatic GitHub Actions workflow every time a new model is created, recording the morphometric values derived from the model's predictions over time. As a real-world application of the proposed framework, we employed the spinal cord segmentation model to update a recently-introduced normative database of healthy participants containing commonly used measures of spinal cord morphometry. Results showed that: (i) our model performs well compared to its previous versions and existing pathology-specific models on the lumbar spinal cord, images with severe compression, and in the presence of intramedullary lesions and/or atrophy achieving an average Dice score of 0.95 ± 0.03; (ii) the automatic workflow for monitoring morphometric drift provides a quick feedback loop for developing future segmentation models; and (iii) the scaling factor required to update the database of morphometric measures is nearly constant among slices across the given vertebral levels, showing minimum drift between the current and previous versions of the model monitored by the framework. The model is freely available in Spinal Cord Toolbox v7.0.

2026-01-21

Imaging neuroscience (published)

openreview.net

Diffusion tractography outside the brain: the road less travelled

Kurt G. Schilling

Irvin Teh

Richard Dortch

Ibrahim Ibrahim

Nian Wang

Bruce Damon

Rory L. Cochran

Alexander Leemans

Diffusion tractography is a powerful MRI technique for mapping fibrous tissue architecture, traditionally applied to the white matter of the… (see more) brain. This report surveys the growing application of tractography to anatomical structures outside the brain, a domain that presents both unique challenges and unique opportunities. We examine its use in the heart, spinal cord, peripheral nerves, brachial plexus, kidney, skeletal muscle, and prostate. For each region, we detail the necessary methodological adaptations for acquisition, modeling, and processing, and highlight the unique anatomical information that can be derived for research and clinical applications. While significant challenges remain - spanning technical hurdles like physiological motion and susceptibility artifacts, to biological complexities like lower anisotropy and the interpretation of streamline validity - tractography beyond the brain provides invaluable, non-invasive insights into tissue micro-organization, opening a new frontier for biomedical imaging.

2025-12-31

Brain Structure and Function (published)

Canadian Spine Society

Adeesya Gausper

Lindsay M Andras

Ken D. Illingworth

David L. Skaggs

Rachelle Imbeault

Justin Dufresne

Sylvain Deschênes

Marjolaine Roy-Beaudry

Jack Legler

Lee Benaroch

Olivia Serhan

Draydon Cheng

Debra Bartley

Patrick Thornley

Khaled Skaik

Genevieve Belanger

Alexandra Stratton

Coyle Matthew

Stephen P. Kingwell

Eve C. Tsai … (see 355 more)

Eugene K. Wai

Hannah Fonteyne

S. Hryniuk

Eric Parent

Eric Huang

K. Stampe

Marie J Beaulieu

Monica Chan

Gloria Thevasagayam

Gabriela Marino-Merlo

Zaid Salaheen

A. Malvea

Leeor Yefet

Ali Moghaddamjou

Sam Molot-Toker

Eisha Christian

Jennifer L Quon

P. B. Dirks

James M. Drake

James T. Rutka

Abhaya V. Kulkarni

Reinhard Zeller

George M. Ibrahim

Julie Joncas

Soraya Barchi

Stefan Parent

Karim Aboelmagd

Archana Sivakuganandan

Amna Zulfiqar

Anne Murphy

Stanley Moll

Julia Sorbara

Brett Rocos

Mark Camp

Geoffrey K. Shumilak

Jalen Dansby

Andrew Chan-Tai-Kong

David E. Lebel

Daisy A Lu

Monique Clar

M. F. Al-Shakfa

Parham Rasoulinejad

Firoz Miyanji

Karim Kantar

Timothy P. Carey

Ravi Ghag

Brent Lanting

Zeeshan Sardar

Saumayajit Basu

Manish Gupta

Abdullah T. Eissa

So Kato

Lawrence G. Lenke

Kristen Jones

Saumyajit Basu

Michael P Kelly

Justin Smith

S. Strantzas

Yong Qiu

Ferran Pellise

A. Alanay

Nasir A. Quraishi

R. Gray

G. Yoshida

Amer Aziz

Jennyfer Paulla Galdino Chaves

Brian Hsu

Stone Sima

Bhisham Singh

Vinay Kulkarni

Ashish D. Diwan

Taryn Ludwig

Farbod Moghaddam

Mina Aminghafari

May Choi

Eliana Seider

Lauren Daunt

Vanessa Vashishth

Ali Ahmadi

P. Brzozowski

Asra Toobaie

Renan R. Fernandes

Anthony V. Perruccio

Amir Mishreky

Mark Alexander MacLean

Lisa Julien

Glenn Patriquin

Jason Leblanc

Ryan Greene

J. Alant

Sean Barry

R. Glennie

Sean D. Christie

Greg MacIntosh

Daniel P Smith

Erin Bigney

Jeffrey Hebert

Eden Richardson

Neil Manson

Edward Abraham

Abdullah Zein

Kyra Holt

Hannah Isaac

Jillian Kearney

Chris Small

Abdullah A.S.M. AlDuwaisan

V. Smith

Tara Whittaker

Denise Eckenswiller

Elias Soumbasis

Robert Tanguay

Celina Nahanni

Tiffany Lung

James J Young

Chloe N Cadieux

Jin Tong Du

Raja Rampersaud

Andrew Glennie

Cynthia Dunning

Emma Jones

William Oxner

Kaike Lobo

P. Łajczak

Cláudia Santos

Numa Rajab

Rafael Oliveira

Y. Silva

R. Barbosa

Aazad Abbas

Gurjovan Sahi

Michael B Johnson

Edward Buchel

Jay Toor

Ronit Kulkarni

Melanie Bertolino

Chase Walton

Gabriella Rivas

John Glaser

Charles Reitman

James Lawrence

Robert Ravinsky

Mohammed Ali Alvi

Avery B. Nathens

Eva Yuan

Yingshi He

Francois Mathieu

Michael C. Sklar

Samuel Yoon

Luke Reda

Hussain Shakil

S. Sadiqi

S. Muijs

Charlotte Dandurand

Marcel Dvorak

F. C. Oner

Vivian Huong Hoang Thien Le

Pascal Mputu Mputu

Francis Bernard

Yiorgos Alexandros Cavayas

H. Hong

D. Kurban

Tianyu Yang

Nader Fallah

Christiana L Cheng

Suzanne Humphreys

Vanessa K. Noonan

Dana El-mughayyar

Colleen O’Connell

Husain Shakil

Zixuan Hu

Christopher W. Smith

Hui M Ling

Zakariya M Khan

Ervin Sejdic

Errol Colak

Christopher Witiw

Maude Duguay

Juan David Cifuentes Hernandez

Jean-Marc Mac-Thiong

Antoine Dionne

Natan Bensoussan

Andréane Richard-Denis

Louis Carrier

Jocelyn Blanchard

Bernard LaRue

Ariane Paquette

Yan Gabriel Morais David Silva

Christopher Nielsen

Vaidehi Bhatt

Stephen J. Lewis

Y. Raja Rampersaud

Brent Rosenstein

Chanelle Montpetit

Nicolas Vaillancourt

Geoffrey Dover

Christina Weiss

Lee Ann Papula

Antonys Melek

Maryse Fortin

A. Fazlollahi

Uri Barak

Samira Kalhor

Joshua Hien Nguyen

Carlo Santaguida

Ruheksh Raj

Kyle Rogan

Allison Marchuk

Erin Barrett

Anand Masson

Brandy Pratt

Danielle Michaud

Kateryna Skyrda

Sierra Simms

Brandon Herrington

Fawaz Siddiqi

Kevin Gurr

Mathieu Chayer

P-J Arnoux

Jeremy Rawlinson

Olumide Aruwajoye

Carl-Eric Aubin

Hussein Samhat

K. Pedro

A. A. Pirshahid

Genevieve Gore

K. Filion

Oliver Lasry

Jordan J. Levett

Nathan Evanview

G. Mcintosh

Nadav Rinott

Mathieu Laflamme

Andy Liu

Alexander Tuchman

Christopher Mikhail

Vivien K. Chan

James McDonald

Julien Zaldivar

G. Lonjon

Matthieu Vassal

Alexandre Dhenin

Alexis Perez

Martin Dupuy

V. Challier

J. Castelain

S. Ghailane

Matthieu Campana

Jonathan Lebhar

Gilles Guerin

Nicolas Pellet

Yann Sabah

T. Chevillotte

A. Darnis

Joseph Cristini

F.X. Ferracci

J. Delambre

Steffen Queinnec

Alexandre Delmotte

Paulo Marinho

R. Gauthé

P. Hannequin

Vianney Gilard

Jean Meyblum

Alexis Perrin

Raphaël Pietton

Nicolas Lonjon

Antoine Gennari

Ahmed Essa

Michael Craig

W. Bradley Jacobs

Peter Lewkonia

Fred Nicholls

Michael Yang

Julien-Cohen Adad

Isaac Wangai

Andrew Nataraj

Osman Hojanepesov

Matthew Skarsgard

Nathan Evaniew

Jérôme Paquet

Perry Dhaliwal

Najmedden Attabib

Chris Bailey

Jefferson R. Wilson

Daniel Kurtz

P. Phan

Christopher Sun

Newton Cho

Abdul Al-Shawwa

Bradley W. Jacobs

Jacques Bouchard

Steven Casha

Stephan duPlessis

Alex Soroceanu

Ganesh Swamy

Kenneth C. Thomas

David W. Cadotte

Landon J Hansen

Stephen Yip

Nicolas Dea

Chetan Bettegowda

Laurence D. Rhines

Daniel M. Sciubba

James M. Schuster

Stefano Boriani

M. Clarke

Paul Arnold

Anne Versteeg

Michael H. Weber

R. de la Garza Ramos

John Shin

Markian Pahuta

A. Luzatti

A. Disch

A. Gasbarrini

Jorrit‐jan Verlaan

William G J Teixeira

Ilya Laufer

Á. Lazáry

Dean Chou

Z. Gokaslan

Addisu Mesfin

Tony Goldschlager

C. Netzer

J. O'Toole

Ori Barzilai

Norio Kawahara

Naresh Kumar

Jeremy J. Reynolds

Rory Goodwin

Jetan Badhiwala

A. Sahgal

Michael G. Fehlings

Alex Kiss

Donald A. Redelmeier

William Chu Kwan

Nikolaus Koegl

Charles G. Fisher

Raphaële Charest-Morin

Alexandra Rocha

Matthew Renaud

Jennifer C. Urquhart

Supriya Singh

Marco Pérez Caceres

Omer Ahmed

Véronique Freire

Jesse Shen

Fidaa Al-shakfa

Danielle Boule

Z. Wang

Christopher S. Lozano

Armaan Malhotra

Vishwathsen Karthikeyan

2025-12-11

Canadian journal of surgery. Journal canadien de chirurgie (published)

Building a library of acute traumatic spinal cord injury images across Canada: a retrospective cohort study protocol

Naama Rotem-Kohavi

Suzanne Humphreys

Vanessa K Noonan

Christiana L Cheng

Mathieu Guay-Paquet

Maxime Bouthillier

Enamundram Naga Karthik

Emma Lichtenstein

Nick Guenther

Naj Attabib

Michael Hardisty

Jetan Badhiwala

Jeremie Larouche

Markian Pahuta

Sean Christie

Michael G Fehlings

Daryl Fourney

Brian K Kwon … (see 6 more)

Jean Marc Mac-Thiong

Jérôme Paquet

Philippe Phan

Christopher Witiw

David W Cadotte

MRI is increasingly recognised as a valuable tool for assessing prognosis and predicting outcomes following traumatic spinal cord injury (SC… (see more)I). Several potential MRI biomarkers have been identified, but efforts are still needed to improve the accuracy and feasibility of these biomarkers in clinical practice. This study aims to build a national Canadian SCI imaging repository for storing and analysing imaging data for SCI, with the goal of improving SCI MRI biomarkers to predict outcomes and inform clinical management. As a substudy of the Rick Hansen SCI Registry (RHSCIR), this retrospective multisite study includes individuals who sustained a traumatic cervical SCI between 2015 and 2021, were previously enrolled in RHSCIR, and had MRI scans acquired within 72 hours of injury and before any surgical intervention. Individuals with a penetrating trauma and/or with any prior spine surgery are excluded. The study principal investigator and research associates, experienced with data curation and with the standardised format and specifications of the Brain Imaging Data Structure standard, guide the site’s curator on the steps to perform image deidentification and curation to create standardised datasets across all sites. These datasets are transferred to a Digital Research Alliance of Canada (‘the Alliance’) server designated for this project and concatenated to form the national Canadian SCI imaging repository (Neurogitea). We are using a semiautomated processing pipeline to quantify lesion morphology, together with additional imaging measures that are manually extracted from the images (for instance, the relative maximal spinal cord compression and the maximum canal compromise). Through linkage to RHSCIR clinical and epidemiological data already available on eligible participants, regression analysis is planned to predict neurological outcomes at discharge, including the American Spinal Injury Association Impairment Scale grade, upper and lower extremity motor and sensory scores. This protocol has been submitted by the participating sites to obtain ethics and institutional approvals prior to the study initiation at each site. All 12 sites across Canada have now obtained ethics and institutional approvals. Study results will be disseminated at local, national and international conferences and by journal publications.

2025-11-30

BMJ Open (published)

RootletSeg: Deep learning method for spinal rootlets segmentation across MRI contrasts

Katerina Krejci

Jiri Chmelik

Sandrine B'edard

Falk Eippert

Ulrike Horn

Virginie Callot

Purpose: To develop a deep learning method for the automatic segmentation of spinal nerve rootlets on various MRI scans. Material and Method… (see more)s: This retrospective study included MRI scans from two open-access and one private dataset, consisting of 3D isotropic 3T TSE T2-weighted (T2w) and 7T MP2RAGE (T1-weighted [T1w] INV1 and INV2, and UNIT1) MRI scans. A deep learning model, RootletSeg, was developed to segment C2-T1 dorsal and ventral spinal rootlets. Training was performed on 76 scans and testing on 17 scans. The Dice score was used to compare the model performance with an existing open-source method. Spinal levels derived from RootletSeg segmentations were compared with vertebral levels defined by intervertebral discs using Bland-Altman analysis. Results: The RootletSeg model developed on 93 MRI scans from 50 healthy adults (mean age, 28.70 years

2025-09-16

ArXiv (preprint)

arxiv.org

Cervical Spinal Cord Magnetization Transfer Ratio and Its Relationship With Clinical Outcomes in Multiple Sclerosis

Lisa Eunyoung Lee

Julien Cohen‐Adad

Irene M. Vavasour

Melanie Guenette

Katherine Sawicka

Neda Rashidi‐Ranjbar

Nathan Churchill

Akash Chopra

Adelia Adelia

Pierre‐Louis Benveniste

Anthony Traboulsee

Nathalie Arbour

Fabrizio Giuliani

Larry D. Lynd

Scott B. Patten

Alexandre Prat

Alice Schabas

Penelope Smyth

Roger Tam

Yunyan Zhang … (see 6 more)

Simon J. Graham

Mojgan Hodaie

Anthony Feinstein

Shannon Kolind

Tom A. Schweizer

Jiwon Oh

The cervical spinal cord (cSC) is highly relevant to clinical dysfunction in multiple sclerosis (MS) but remains understudied using quantita… (see more)tive magnetic resonance imaging (MRI). We assessed magnetization transfer ratio (MTR), a semi‐quantitative MRI measure sensitive to MS‐related tissue microstructural changes, in the cSC and its relationship with clinical outcomes in radiologically isolated syndrome (RIS) and MS. MTR data were acquired from 52 RIS, 201 relapsing–remitting MS (RRMS), 47 primary progressive MS (PPMS), and 43 control (CON) participants across four sites in the Canadian Prospective Cohort Study to Understand Progression in MS (CanProCo) using 3.0 T MRI systems. Mean MTR was compared between groups in whole cSC and sub‐regions between C2‐C4. Multiple linear regression was used to evaluate relationships between MTR and clinical outcomes, including the expanded disability status scale (EDSS), walking speed test (WST), and manual dexterity test (MDT). There were consistent group differences in MTR, which were most pronounced between PPMS and CON (−5.8% to −3.7%, p ≤ 0.01). In PPMS, lower MTR was associated with greater disability as measured by EDSS (β = −0.3 to −0.1, p ≤ 0.03), WST (β = −0.9 to −0.5, p ≤ 0.04), and MDT (β = −0.6 and − 0.5, p = 0.04). In RRMS, MTR was associated with only EDSS (β = −0.1, p ≤ 0.03). In this large sample of RIS and MS, cSC MTR was lowest in PPMS, with associations between MTR and clinical outcomes in MS but not RIS. These findings suggest that MTR provides important information about the underlying tissue microstructural integrity of the cSC relevant to clinical disability in established MS.

2025-06-28

Annals of Clinical and Translational Neurology (published)

Ultrasound and MRI-based evaluation of relationships between morphological and mechanical properties of the lower lumbar multifidus muscle in chronic low back pain

Neda Naghdi

Sara Masi

Cleo Bertrand

Brent Rosenstein

Hassan Rivaz

Mathieu Roy

Maryse Fortin

While lumbar multifidus (MF) muscle alterations are linked to low back pain (LBP), the structure-function relationship is not fully understo… (see more)od. This study aims to evaluate the relationship between fatty degeneration of the lumbar MF muscle and its function in individuals with and without LBP. The study included 25 participants with chronic nonspecific LBP and 25 age- and sex-matched healthy controls. Participants underwent MRI assessment for MF fat infiltration, utilizing IDEAL fat-water images. Ultrasound measures evaluated MF function, including shear-wave elastography (SWE) for stiffness/elasticity and thickness ratio from rest to submaximal contraction. All measurements were acquired at L4/L5 and L5/S1 spinal levels, bilaterally. Bivariate and multivariable linear regression models were used to assess the relationship between morphology and function, while age, sex, body max index (BMI), physical activity levels, and LBP status were considered as covariates. Fifty participants (26 females) were included (mean age: 39.22 ± 11.67). Greater % MF fat at L4/L5 was significantly associated with greater MF SWE ratio (p = 0.002). No significant bivariate or multivariable relationships were found between MF fat infiltration and MF thickness ratio. Participants with LBP exhibited lower contraction ratios (p = 0.017) and higher SWE during contraction (p = 0.03) at L4/L5 compared to controls. This study highlights a positive association between MF fat infiltration and SWE-based stiffness measures at L4/L5, suggesting altered muscle composition may impacts MF function. However, no relationship was found between MF fat infiltration and contraction. Participants with LBP demonstrated distinct deficits in muscle activation, supporting the need for targeted rehabilitation strategies addressing these functional impairments.

2025-06-08

European Spine Journal (published)

Multi‐center benchmarking of cervical spinal cord RF coils for 7 T MRI: A traveling spines study

Eva Alonso‐Ortiz

Daniel Papp

Robert L. Barry

Kyota Poëti

Alan C. Seifert

Kyle M. Gilbert

Nibardo Lopez‐Rios

Jan Paska

Falk Eippert

Nikolaus Weiskopf

Laura Beghini

Nadine N. Graedel

Robert Trampel

Martina F. Callaghan

Christoph S. Aigner

Patrick Freund

Maryam Seif

Aurélien Destruel

Virginie Callot

Johanna Vannesjo … (see 1 more)

Julien Cohen‐Adad

The depth within the body, small diameter, long length, and varying tissue surrounding the spinal cord impose specific considerations when d… (see more)esigning RF coils. The optimal coil configuration for 7 T cervical spinal cord MRI is unknown and currently there are very few coil options. The purpose of this work was (1) to establish a quality control protocol for evaluating 7 T cervical spinal cord coils, and (2) to use that protocol to evaluate the performance of four different coil designs. Three healthy volunteers and a custom anthropomorphic phantom (the traveling spines cohort) were scanned at seven 7 T imaging centers using a common protocol and each center's specific cervical spinal cord coil. Four different coil designs were tested (two in‐house, one Rapid Biomedical, and one MRI.TOOLS design). The Rapid Biomedical coil was found to have the highest B1+ efficiency, whereas one of the in‐house designs (NeuroPoly Lab) had the highest SNR and the largest spinal cord coverage. The MRI.TOOLS coil had the most uniform B1+ profile along the cervical spinal cord; however, it was limited in its ability to provide the requested flip angles (especially for larger individuals). The latter was also the case for the second in‐house coil (MSSM). The results of this study serve as a guide for the spinal cord MRI community in selecting the most suitable coil based on specific requirements and offer a standardized protocol for assessing future coils.

2025-05-19

Magnetic Resonance in Medicine (published)

Influence of scanning plane on Human Spinal Cord functional Magnetic Resonance echo planar imaging

Marta Moraschi

Silvia Tommasin

Laura Maugeri

Mauro DiNuzzo

Marco Masullo

Fabio Mangini

Lorenzo Giovannelli

Daniele Mascali

Tommaso Gili

Valerio Pisani

Ugo Nocentini

Federico Giove

Michela Fratini

BACKGROUND: Functional Magnetic Resonance Imaging (fMRI) is based on the Blood Oxygenation Level Dependent contrast and has been exploited f… (see more)or the indirect study of the neuronal activity within both the brain and the spinal cord. However, the interpretation of spinal cord fMRI (scfMRI) is still controversial and its diffusion is rather limited because of technical limitations. Overcoming these limitations would have a beneficial effect for the assessment and follow-up of spinal injuries and neurodegenerative diseases. PURPOSE: This study was aimed at systematically verify whether sagittal scanning in scfMRI using EPI readout is a viable alternative to the more common axial scanning, and at optimizing a pipeline for EPI-based scfMRI data analysis, based on Spinal Cord Toolbox (SCT). METHODS: Forty-five healthy subjects underwent MRI acquisition in a Philips Achieva 3T MRI scanner. T2*-weighted fMRI data were acquired using a GE-EPI sequence along sagittal and axial planes during an isometric motor task. Differences on benchmarks were assessed via paired two-sample t-test at p=0.05. RESULTS: We investigated the impact of the acquisition strategy by means of various metrics such as Temporal Signal to Noise Ratio (tSNR), Dice Coefficient to assess geometric distortions, Reproducibility and Sensitivity. tSNR was higher in axial than in sagittal scans, as well as reproducibility within the whole cord mask (t=7.4, p0.01) and within the GM mask (t=4.2, p0.01). The other benchmarks, associated with distortion and functional response, showed no differenc

2025-05-11

PLOS One (published)

arxiv.org

Impact of through‐slice gradient optimization for dynamic slice‐wise shimming in the cervico‐thoracic spinal cord

Arnaud Breheret

Alexandre D'Astous

Yixin Ma

Jason P. Stockmann

Julien Cohen‐Adad

This study investigates the effectiveness of through‐slice gradient optimization in dynamic slice‐wise B0 shimming of the cervico‐thor… (see more)acic spinal cord to enhance signal recovery in gradient‐echo (GRE) EPI sequences commonly used in functional MRI studies. Six volunteers underwent MRI acquisitions with dynamic shim updating (DSU) using a custom‐built 15‐channel AC/DC coil at 3 T. A magnetization‐prepared rapid gradient echo was acquired to segment the spine and to provide a clear image of the anatomical region of interest in the figures. GRE B0 field maps were used to measure field homogeneity before and after shimming; the pre‐shimming field map was used for optimization. Shimmed fields were dynamically applied to GRE–echo planar imaging acquisitions simulating functional MRI acquisitions under two shimming conditions: DSU with and without through‐slice gradient consideration. DSU with through‐slice gradient optimization increased the temporal signal‐to‐noise ratio at the T2 vertebral level by 201% compared with volume‐wise shim and by 28% compared with DSU without through‐slice. The residual geometric distortions were similar between DSU with and without through‐slice gradient optimization. A high signal loss penalty parameter was effective in simulations for reducing through‐slice gradient‐induced signal loss but led to instability and reduced image quality in actual acquisitions due to excessive in‐plane B0 inhomogeneities. Introducing a carefully balanced through‐slice gradient parameter in slice‐wise shimming substantially improves signal recovery in axial GRE images of the spinal cord, without compromising in‐plane homogeneity. This effective approach can advance spinal cord functional MRI applications at high field strengths.

2025-04-30

Magnetic Resonance in Medicine (published)