Date: 2026-01-13

# Testing the Dimensions with CIFTI Files

#### 2026-01-13

    install_dir = tempfile()
    dir.create(install_dir)

# Load MSC data and test data from cifti package

Using `download_cifti_data()` and `download.file` to download the test data.

    library(cifti)
    download_cifti_data(outdir = install_dir)

    ## [1] "/var/folders/1s/wrtqcpxn685_zk570bnx9_rr0000gr/T//RtmpOoSPG4/filee204e8eb9b/cifti-2_test_data/ones.dscalar.nii"
    ## [2] "/var/folders/1s/wrtqcpxn685_zk570bnx9_rr0000gr/T//RtmpOoSPG4/filee204e8eb9b/cifti-2_test_data/Conte69.MyelinAndCorrThickness.32k_fs_LR.dscalar.nii"
    ## [3] "/var/folders/1s/wrtqcpxn685_zk570bnx9_rr0000gr/T//RtmpOoSPG4/filee204e8eb9b/cifti-2_test_data/Conte69.R.inflated.32k_fs_LR.surf.gii"
    ## [4] "/var/folders/1s/wrtqcpxn685_zk570bnx9_rr0000gr/T//RtmpOoSPG4/filee204e8eb9b/cifti-2_test_data/Conte69.L.inflated.32k_fs_LR.surf.gii"
    ## [5] "/var/folders/1s/wrtqcpxn685_zk570bnx9_rr0000gr/T//RtmpOoSPG4/filee204e8eb9b/cifti-2_test_data/Conte69_AverageT1w_restore.nii.gz"
    ## [6] "/var/folders/1s/wrtqcpxn685_zk570bnx9_rr0000gr/T//RtmpOoSPG4/filee204e8eb9b/cifti-2_test_data/Conte69.MyelinAndCorrThickness.32k_fs_LR.ptseries.nii"
    ## [7] "/var/folders/1s/wrtqcpxn685_zk570bnx9_rr0000gr/T//RtmpOoSPG4/filee204e8eb9b/cifti-2_test_data/Conte69.parcellations_VGD11b.32k_fs_LR.dlabel.nii"
    ## [8] "/var/folders/1s/wrtqcpxn685_zk570bnx9_rr0000gr/T//RtmpOoSPG4/filee204e8eb9b/cifti-2_test_data/Conte69.MyelinAndCorrThickness.32k_fs_LR.dtseries.nii"

Here we will download a NIfTI file from the MSC dataset:

    mscfile = file.path(
      install_dir,
      "sub-MSC01_ses-func01_task-rest_bold_32k_fsLR.dtseries.nii")
    if (!file.exists(mscfile)) {
      # url = paste0(
      #   "https://openneuro.org/crn/datasets/ds000224/snapshots/00002/files/",
      #   "derivatives:", "surface_pipeline:", "sub-MSC01:",
      #   "processed_restingstate_timecourses:",  "ses-func01:cifti:",
      #   "sub-MSC01_ses-func01_task-rest_bold_32k_fsLR.dtseries.nii")
      url = paste0("https://s3.amazonaws.com/openneuro/ds000224/ds000224_R1.0.2/",
                   "uncompressed/derivatives/surface_pipeline/sub-MSC01/",
                   "processed_restingstate_timecourses/ses-func01/cifti/",
                   "sub-MSC01_ses-func01_task-rest_bold_32k_fsLR.dtseries.nii")
      res = download.file(url = url,
        destfile = mscfile, mode = "wb")
      stopifnot(file.exists(mscfile))
    }

    test_dir = file.path(install_dir, "cifti-2_test_data")

    ds <- read_cifti(
      file.path(test_dir,
                "Conte69.MyelinAndCorrThickness.32k_fs_LR.dscalar.nii")
      )

    ## Parsing Volume Data

    ## Parsing Surface Data

    ## Parsing Parcel Data

    ## Parsing Named Map Data

    ## Parsing Brain Model Data

    dt <- read_cifti(
      file.path(test_dir,
                "Conte69.MyelinAndCorrThickness.32k_fs_LR.dtseries.nii")
      )

    ## Parsing Volume Data

    ## Parsing Surface Data

    ## Parsing Parcel Data

    ## Parsing Named Map Data

    ## Parsing Brain Model Data

    pt <- read_cifti(
      file.path(test_dir,
                "Conte69.MyelinAndCorrThickness.32k_fs_LR.ptseries.nii")
      )

    ## Parsing Volume Data

    ## Parsing Surface Data

    ## Parsing Parcel Data

    ## Parsing Named Map Data

    ## Parsing Brain Model Data

    dl <- read_cifti(
      file.path(test_dir,
                "Conte69.parcellations_VGD11b.32k_fs_LR.dlabel.nii")
      )

    ## Parsing Volume Data

    ## Parsing Surface Data

    ## Parsing Parcel Data

    ## Parsing Named Map Data

    ## Parsing Brain Model Data

    msc <- read_cifti(mscfile, trans_data = FALSE)

    ## Parsing Volume Data

    ## Parsing Surface Data

    ## Parsing Parcel Data

    ## Parsing Named Map Data

    ## Parsing Brain Model Data

    msc_trans <- read_cifti(mscfile, trans_data = TRUE)

    ## Parsing Volume Data

    ## Parsing Surface Data

    ## Parsing Parcel Data

    ## Parsing Named Map Data

    ## Parsing Brain Model Data

## For reference: MSC 01 (65890 * 818) (using matlab ft_read_cifti), showing first 5 rows & columns

    ##            V1       V2       V3       V4       V5
    ## [1,]  1.60060  2.27580  1.60540  0.12593 -0.49364
    ## [2,]  1.85790  2.55780  1.59500 -0.84614 -2.63840
    ## [3,]  0.33651  1.46200  1.77790  0.34857 -1.93580
    ## [4,]  0.95052  0.71743 -0.94483 -2.33310 -2.10040
    ## [5,] -2.08590 -1.99750 -1.24970 -0.93712 -0.58043

## MSC Sub-01 Session 1 (sub-MSC01_ses-func01_task-rest_bold_32k_fsLR.dtseries.nii)

`read_cifti(fname = , trans_data = FALSE)` * header dimension shows 65890 * 818 * read in file shows 65890 * 818 by setting trans_data to FALSE

    msc$hdr

    ## NIfTI-1 format
    ##   Type            : nifti
    ##   Data Type       : 16 (FLOAT32)
    ##   Bits per Pixel  : 32
    ##   Slice Code      : 0 (Unknown)
    ##   Intent Code     : 3002 ()
    ##   Qform Code      : 0 (Unknown)
    ##   Sform Code      : 0 (Unknown)
    ##   Dimension       : 1 x 1 x 1 x 1 x 65890 x 818
    ##   Pixel Dimension : 1 x 1 x 1 x 1 x 1 x 1
    ##   Voxel Units     :
    ##   Time Units      : sec

    dim(msc$data)

    ## [1] 65890   818

    msc$data[1:5,1:5]

    ##           [,1]      [,2]      [,3]      [,4]      [,5]
    ## [1,]  1.600599  2.275847  1.605402  0.125929 -0.493640
    ## [2,]  1.857941  2.557801  1.595005 -0.846137 -2.638434
    ## [3,]  0.336508  1.461959  1.777888  0.348566 -1.935833
    ## [4,]  0.950522  0.717431 -0.944832 -2.333094 -2.100426
    ## [5,] -2.085948 -1.997536 -1.249652 -0.937115 -0.580428

- If transpose is not set to FALSE (default is TRUE), it will return a 818 * 65890 that is filled correctly, and user just have to `t()` the `cii$data`

    t(msc_trans$data[1:5,1:5])

    ##           [,1]      [,2]      [,3]      [,4]      [,5]
    ## [1,]  1.600599  2.275847  1.605402  0.125929 -0.493640
    ## [2,]  1.857941  2.557801  1.595005 -0.846137 -2.638434
    ## [3,]  0.336508  1.461959  1.777888  0.348566 -1.935833
    ## [4,]  0.950522  0.717431 -0.944832 -2.333094 -2.100426
    ## [5,] -2.085948 -1.997536 -1.249652 -0.937115 -0.580428

## Data where dimensions are row x dense loads fine. Updated function loads them the same way as before.

### Conte69.MyelinAndCorrThickness.32k_fs_LR.dscalar.nii

- Dense file “d”, vertex level data
- Header shows dimension as rows * dense

    ds$hdr

    ## NIfTI-1 format
    ##   Type            : nifti
    ##   Data Type       : 16 (FLOAT32)
    ##   Bits per Pixel  : 32
    ##   Slice Code      : 0 (Unknown)
    ##   Intent Code     : 3006 ()
    ##   Qform Code      : 0 (Unknown)
    ##   Sform Code      : 0 (Unknown)
    ##   Dimension       : 1 x 1 x 1 x 1 x 2 x 60951
    ##   Pixel Dimension : 1 x 1 x 1 x 1 x 1 x 1
    ##   Voxel Units     :
    ##   Time Units      : sec

    attributes(ds$BrainModel[[1]])

    ## $IndexOffset
    ## [1] 0
    ##
    ## $IndexCount
    ## [1] 30424
    ##
    ## $BrainStructure
    ## [1] "CIFTI_STRUCTURE_CORTEX_LEFT"
    ##
    ## $ModelType
    ## [1] "CIFTI_MODEL_TYPE_SURFACE"
    ##
    ## $SurfaceNumberOfVertices
    ## [1] 32492

    attributes(ds$BrainModel[[2]])

    ## $IndexOffset
    ## [1] 30424
    ##
    ## $IndexCount
    ## [1] 30527
    ##
    ## $BrainStructure
    ## [1] "CIFTI_STRUCTURE_CORTEX_RIGHT"
    ##
    ## $ModelType
    ## [1] "CIFTI_MODEL_TYPE_SURFACE"
    ##
    ## $SurfaceNumberOfVertices
    ## [1] 32492

    dim(ds$data)

    ## [1] 60951     2

    head(ds$data)

    ##          [,1]     [,2]
    ## [1,] 1.321855 3.195882
    ## [2,] 1.373803 2.141433
    ## [3,] 1.408264 3.028383
    ## [4,] 1.244012 3.237031
    ## [5,] 1.479665 2.216135
    ## [6,] 1.266741 2.795304

### Conte69.MyelinAndCorrThickness.32k_fs_LR.dtseries.nii

    dt$hdr

    ## NIfTI-1 format
    ##   Type            : nifti
    ##   Data Type       : 16 (FLOAT32)
    ##   Bits per Pixel  : 32
    ##   Slice Code      : 0 (Unknown)
    ##   Intent Code     : 3002 ()
    ##   Qform Code      : 0 (Unknown)
    ##   Sform Code      : 0 (Unknown)
    ##   Dimension       : 1 x 1 x 1 x 1 x 2 x 60951
    ##   Pixel Dimension : 1 x 1 x 1 x 1 x 1 x 1
    ##   Voxel Units     :
    ##   Time Units      : sec

    attributes(dt$BrainModel[[1]])

    ## $IndexOffset
    ## [1] 0
    ##
    ## $IndexCount
    ## [1] 30424
    ##
    ## $BrainStructure
    ## [1] "CIFTI_STRUCTURE_CORTEX_LEFT"
    ##
    ## $ModelType
    ## [1] "CIFTI_MODEL_TYPE_SURFACE"
    ##
    ## $SurfaceNumberOfVertices
    ## [1] 32492

    attributes(dt$BrainModel[[2]])

    ## $IndexOffset
    ## [1] 30424
    ##
    ## $IndexCount
    ## [1] 30527
    ##
    ## $BrainStructure
    ## [1] "CIFTI_STRUCTURE_CORTEX_RIGHT"
    ##
    ## $ModelType
    ## [1] "CIFTI_MODEL_TYPE_SURFACE"
    ##
    ## $SurfaceNumberOfVertices
    ## [1] 32492

    dim(dt$data)

    ## [1] 60951     2

    head(dt$data)

    ##          [,1]     [,2]
    ## [1,] 1.321855 3.195882
    ## [2,] 1.373803 2.141433
    ## [3,] 1.408264 3.028383
    ## [4,] 1.244012 3.237031
    ## [5,] 1.479665 2.216135
    ## [6,] 1.266741 2.795304

### Conte69.MyelinAndCorrThickness.32k_fs_LR.ptseries.nii

- parcel level

    pt$hdr

    ## NIfTI-1 format
    ##   Type            : nifti
    ##   Data Type       : 16 (FLOAT32)
    ##   Bits per Pixel  : 32
    ##   Slice Code      : 0 (Unknown)
    ##   Intent Code     : 3004 ()
    ##   Qform Code      : 0 (Unknown)
    ##   Sform Code      : 0 (Unknown)
    ##   Dimension       : 1 x 1 x 1 x 1 x 2 x 54
    ##   Pixel Dimension : 1 x 1 x 1 x 1 x 1 x 1
    ##   Voxel Units     :
    ##   Time Units      : sec

    dim(pt$data)

    ## [1] 54  2

    head(pt$data)

    ##          [,1]     [,2]
    ## [1,] 1.431012 2.515503
    ## [2,] 1.392534 2.339441
    ## [3,] 1.521327 2.154038
    ## [4,] 1.498012 1.684434
    ## [5,] 1.618780 2.652969
    ## [6,] 1.511189 2.089453

### Conte69.parcellations_VGD11b.32k_fs_LR.dlabel.nii (dense label on vertex level)

- dense label

    dl$hdr

    ## NIfTI-1 format
    ##   Type            : nifti
    ##   Data Type       : 16 (FLOAT32)
    ##   Bits per Pixel  : 32
    ##   Slice Code      : 0 (Unknown)
    ##   Intent Code     : 3007 ()
    ##   Qform Code      : 0 (Unknown)
    ##   Sform Code      : 0 (Unknown)
    ##   Dimension       : 1 x 1 x 1 x 1 x 3 x 64984
    ##   Pixel Dimension : 1 x 1 x 1 x 1 x 1 x 1
    ##   Voxel Units     :
    ##   Time Units      : sec

    dim(dl$data)

    ## [1] 64984     3

    head(dl$data)

    ##      [,1] [,2] [,3]
    ## [1,]    0   67    0
    ## [2,]    0   59    0
    ## [3,]    8   56    0
    ## [4,]    8   54    0
    ## [5,]   14   87    0
    ## [6,]    0   64    0