Protocol 2 - MRI data protocol

For this protocol you will need to have installed :

- Anaconda

- FSL 6.0 

- The meld_focal_epilepsy package 

- The mfe_env conda environment

Install Anaconda & FSL

To check if you already have anaconda installed, in your terminal window run:

conda --version
```It should return the version of your current conda installation e.g "conda 4.10.1"

If not, please refer to the following instructions to install anaconda on your computer :

[https://www.anaconda.com/products/individual-d](https://www.anaconda.com/products/individual-d)







To check if you already have  **FSL**  installed, in your terminal window run:   

flirt --version

If not, or if you don't have the version 6, please refer to the following instructions to install FSL 6.0 on your computer :

[https://fsl.fmrib.ox.ac.uk/fsl/fslwiki/FslInstallation](https://fsl.fmrib.ox.ac.uk/fsl/fslwiki/FslInstallation)

Install meld_focal_epilepsy github & create environment:

1. Open a terminal and move to the folder you want to saved the package in:

cd <path_to_meld_focal_epilepsy_github_folder>
```2) Copy from GitHub the package by pasting the following sentence :     

git clone https://github.com/MELDProject/meld_focal_epilepsy.git

    Check if you have a folder called meld_focal_epilespy in <path_to_meld_focal_epilepsies_folder>

3) Create the environment :    

cd <path_to_meld_focal_epilepsy_github_folder>/meld_focal_epilepsy/scripts conda env create -f mfe_env.yml

conda activate mfe_env

    e.g

    

<img src="https://static.yanyin.tech/literature_test/protocol_io_true/protocols.io.3byl4k8jjvo5/image.png" alt="" loading="lazy" title=""/>

Your meld_focal_epilepsy package is ready to be used !



 **Note**  : you will have to activate your environment every time you open a new terminal and you want to use the meld_focal_epilepsy package

Prepare your data

Download the meld_focal_epilepsy_data folder from : https://figshare.com/s/763e50f4eb51a4f76f58

Keep note of where you save this folder as it will be your data folder : <path_to_meld_focal_epilepsy_data_folder>

You will need to unzip the folder :

cd <path_to_meld_focal_epilepsy_data_folder> 
tar -xzvf meld-focal-epilepsy-data.tar.gz

Anonymous participant IDs

During Protocol 1 each participant should have been given an anonymous ID according to the following naming structure:

MELD_[site code]_[patient/control]_number

In the meld_focal_epilepsy_data/participants folder copy the template file structure called meld_template and rename the folder with the participants anonymous ID. This can either be done by right clicking on the folder clicking rename and typing in the anonymous ID OR in your terminal window:

cd <path_to_meld_focal_epilepsy_folder>/meld_focal_epilepsy/participants
mv meld_template <MELD_anonymous_ID>
```e.g. mv meld_template MELD_H1_P_0001





Further details about the naming structure:



[site code] =  site identifier which will be provided to you e.g. H1 for Great Ormond Street Hospital



[patient/control] = P if patient, C if control. 



 _If participant was included in the FCD study and has an ID such as MELD_H1_15T_FCD_0001, the ID should be kept the same. I.e. Use the original FCD flag and scanner flag._ 



 _If control was included in the FCD study and has an ID such as MELD_H1_3T_C_0001, the ID should be kept the same._ 





[number] = 0001, 0002 etc.



Examples of participant IDs:

MELD_H1_P_0001

MELD_H1_C_0002

MELD_H2_FCD_0042



Please make sure to securely keep a spreadsheet at your centre which links the anonymous IDs used in this study back to the IDENTIFIABLE patient data. THIS MUST NOT BE SHARED and should be kept securely! 

The following MRI data should be retrieved off the hospital system / research database for each participant and stored in the relevant folder for each participant:

A	B	C	D	E
MRI scan	Notes on data	Essential / where available	Folder to store data	Data formats accepted
T1-weighted preoperative	3D 1.5T, 3T or 7T	Essential	t1	dicom, nifti
T2 preoperative	3D or 2D coronal	Where available	t2	dicom, nifti
FLAIR preoperative	3D or 2D coronal	Where available	flair	dicom, nifti
DWI preoperative (diffusion weighted data, bval and bvec)	3D	Where available	dwi	dicom, nifti
T1-weighted postoperative	3D 1.5T, 3T or 7T	Essential in operated patients	postop_t1	dicom, nifti

Please note: the MRI data must NOT have contrast (e.g. gadolinium contrast)

Within the meld_template are 1.5T, 3T and 7T folders and within these there are folders to store the MRI data. Please save the patient's MRI data in the correct folder.

If you have MRI data from multiple scanner field strengths for the same patient (e.g. 1.5T and 3T data for a patient) - it would be wonderful to have both, so we can compare how the classifier is able to perform on data from different scanner field strengths.

Here is an overview of the folder structure:

Diffusion Weighted Data:

Please note if you are providing the data in nifti format you need to provide the following files:

dwi.nii.gz

dwi.bval

dwi.bvec

If you are providing the data in dicom format, the script in the subsequent section will create these files.

Once you have retrieved all your patient / control MRI data and stored it in the MELD_focal_epilepsy file structure, you need to run the " meld_bidsify_data_step1.py " script. This script will convert any dicom data into nifti format and save them alongside dicoms

Note : you need to have your mfe_env environment activated : conda activate mfe_env

Please note that the meld_focal_epilepsy_github_folder contains the scripts and is different from the meld_focal_epilepsy_data_folder which should contains the data.

To run this script on all participants: Open a terminal window and type:

cd <path_to_meld_focal_epilepsy_github_folder>/meld_focal_epilepsy/scripts

python meld_bidsify_data_step1.py -d <path_to_meld_focal_epilepsy_data_folder>/meld_focal_epilepsy_data

Note :

This script also coregister FLAIR volumes to T1 if both available, and saves it in the 'flair' folder

You can now use the nifti T1 volume, and the additional coregistered FLAIR volume to create the lesion mask if not already provided.

This section (Substeps 1 - 7) details how to create a lesion mask in ITK-SNAP and save it as a Nifti file.

Lesion masks should ideally be created for all patients included in the MELD Project EXCEPT patients with:

• hippocampal sclerosis

• or patients who are MRI negative

If your centre has an established method to create lesion masks / has already created lesion mask:

You do not need to redo them or change your method. The lesion masks will need to be converted to Nifti format. Please save the lesion mask as lesion.nii.gz or lesion.nii in the lesion_mask folder. If the lesion mask was created based on a 1.5T scan, please save in the 1.5T folder. If the lesion mask was created based on a 3T scan, please save in the 3T folder etc.

How to create a lesion mask:

The lesion mask should be done on the 3D T1-weighted scan but other scans e.g. FLAIR and the post-operative T1-weighted can be used to assist in defining the lesion. We provide the FLAIR coregistered (FLAIR_coreg.nii) which can be used to help delineate the lesion.

You may need assistance from a neuroradiologist at your centre for the subtle lesions.

If you have multiple T1-weighted scans at different field strengths - please create the lesion mask based on the T1-weighted scan you can visualise the lesion best on.

If the patient has hippocampal sclerosis OR is MRI negative there is no need to create a lesion mask.

If the patient is MRI-negative but with histological confirmation, the post-operative scan and other corroborative evidence such as EEG, PET, sEEG etc. can be used to help define where the lesion was on the preoperative scan in order to create the lesion mask.

If it is NOT possible to create a lesion mask. Please still include this patient in the study. In the RedCap Participant information survey under the question "Have you provided a lesion mask for this patient?" Click No

If you have any questions or run into problems, please feel free to contact the MELD project: (meld.study@gmail.com).

Downloading ITK-SNAP:

Click on the link below and download version 3.8.0 for windows / mac / linux depending on your workstation:

http://www.itksnap.org/pmwiki/pmwiki.php?n=Downloads.SNAP3

Follow the tutorial provided for the installation: http://www.itksnap.org/pmwiki/pmwiki.php?n=Documentation.TutorialSectionInstallation

Before starting manual lesion masking:

We advise watching part of the ITK-SNAP webinar:

If you start at 9minutes 57 seconds and watch until 12 minutes 5 seconds, you can watch the part of navigating an image in ITK-SNAP and manual segmentation. You may want to pause / rewatch the manual segmentation example as it is very fast but shows you 3 tools you can use to help create your lesion masks - polygon; paintbrush and smart brush

https://www.youtube.com/watch?v=Wob8beX88Ks

Here is a useful introductory guide on how to use ITK-SNAP:

http://www.itksnap.org/pmwiki/uploads/Train/RSNA2016-Manual-Guido-Final.pdf

Slides

11-14: Image navigation

16-22: Manual segmentation

24: Loading and saving manual segmentations

There are also many other useful youtube tutorials on how to manually segment using ITK-SNAP. Here is a longer (18 minute) but much more detailed webinar which is very useful. In this example they use segmentation of the hippocampal subfields as an example.

https://www.youtube.com/watch?v=OpYJiY_GoeY

Example manual segmentation of a FCD Type IIB - Opening the MRI scans and navigating through them

Open ITK-SNAP and click open image

Then search for the MRI image (usually T1-weighted) of the patient who's lesion you are going to segment

In this example I have opened a 3T FLAIR image:

On the toolbar, the cursor is clicked, so I can navigate through the MRI to find the lesion.

If I want to add another MRI scan (e.g. the co-registered 3T T1-weighted), I can click file -> add another image

Example manual segmentation of a FCD Type IIB - Opening the MRI scans and navigating through them

Open ITK-SNAP and click open image

Then search for the MRI image (usually T1-weighted) of the patient who's lesion you are going to segment

Example manual segmentation of a FCD Type IIB

Once you have identified the lesion, you may want to zoom in on it. Click the magnifying glass and increase the zoom until you can clearly see the lesion

Then click the paintbrush and choose your brush style (I use the circle), and brush size. To create your lesion mask in 3D click 3D, to mask slice by slice, unclick the 3D button.

You can now start to mask your lesion. As you can see the "Active label" is 1 - this means that the voxels of the lesion will all have a value of 1. If you make a mistake and want to delete some of the voxels you have labelled, you can right click on them.

Saving the lesion label

Click Segmentation -> Save Segmentation Image

Save image as lesion.nii.gz in the patient's MELD folder e.g. MELD_H1_0001/3T/lesion_mask

Creating the lesion label if there is more than 1 lesion e.g. FCD IIIA where you have a hippocampal lesion and a cortical lesion

Mask one lesion using active label 1. Then change the label to 2 and mask the other lesion:

Save the lesions as before as "lesion.nii.gz". The first lesion mask will have values of 1 and the second will have values of 2.

Run meld_bidsify_data_step2.py to convert in BIDS format

Once you have placed the lesion nifti file into the right lesion_mask folder, you need to run " meld_bidsify_data_step2.py " script. This script will :

1. Reorganise MRI data into BIDS structure saved into meld_bids folder

2. Strip any identifiable header information from the scans

3. Deface the MRI data

4. Compress the meld_bids folder into different batchs

To run this script you need to provide a txt file with the list of participants you want to include in the batch.

To create the list of participants :

1) Open a terminal window

 cd <path_to_meld_focal_epilepsy_data_folder>/meld_focal_epilepsy_data
 nano list_participants_batch_<date_as_ddmmyyyy>.txt
```     Then type the MELD IDs of the participants you would like to run the script on. Press enter between each         participant_id:

     e.g.

     MELD_H1_3T_P_0001

     MELD_H1_3T_P_0002

     MELD_H1_15T_P_0001

     MELD_H1_15T_C_0002

     

File handling in nano

     Ctrl+S Save current file

     Ctrl+X Close buffer, exit from nano

     

Alternatively use any text editor to save your list of participant ids at list_participants_batch_<date_as_ddmmyyyy>.txt.

 



Once you have the participants file, type:

cd <path_to_meld_focal_epilepsy_github_folder>/meld_focal_epilepsy/scripts

python meld_bidsify_data_step2.py -d <path_to_meld_focal_epilepsy_data_folder>/meld_focal_epilepsy_data -ids <path_to_meld_focal_epilepsy_data_folder>/meld_focal_epilepsy_data/list_participants_batch_.txt

You can find your new bids folder and its zipped batches at <path_to_meld_focal_epilepsy_data_folder>/meld_focal_epilepsy_data/meld_bids

The files to share begin with: "share_data_part"



 **Note**  : remember to keep track of the subjects you have already converted with the participants list file. 

Note: Dropbox is now deprecated and files will be shared via File Request on OneDrive

Please contact meld.study@gmail.com and provide the email(s) of the person(s) who will be uploading the data. We will send you a file request to upload the data to a secure drop-only folder.

Upload each zipped batch

Please note – due to the file sizes, it may take a while to upload!

A member of the MELD team will confirm the reception of the files

REMINDER: ONLY SEND ANONYMISED DATA OVER