The dataset viewer is not available for this split.
Error code: StreamingRowsError
Exception: CastError
Message: Couldn't cast
MagneticFieldStrength: double
ImagingFrequency: double
RepetitionTime: double
FlipAngle: int64
Manufacturer: string
ManufacturersModelName: string
PulseSequenceDetails: string
B0_dir: list<item: double>
child 0, item: double
VoxelSize: list<item: double>
child 0, item: double
EchoTime: double
EchoNumber: int64
ImageType: list<item: string>
child 0, item: string
Units: string
to
{'MagneticFieldStrength': Value('float64'), 'ImagingFrequency': Value('float64'), 'RepetitionTime': Value('float64'), 'FlipAngle': Value('int64'), 'Manufacturer': Value('string'), 'ManufacturersModelName': Value('string'), 'PulseSequenceDetails': Value('string'), 'B0_dir': List(Value('float64')), 'VoxelSize': List(Value('float64')), 'EchoTime': Value('float64'), 'EchoNumber': Value('int64'), 'ImageType': List(Value('string'))}
because column names don't match
Traceback: Traceback (most recent call last):
File "/src/services/worker/src/worker/utils.py", line 147, in get_rows_or_raise
return get_rows(
dataset=dataset,
...<4 lines>...
column_names=column_names,
)
File "/src/libs/libcommon/src/libcommon/utils.py", line 272, in decorator
return func(*args, **kwargs)
File "/src/services/worker/src/worker/utils.py", line 127, in get_rows
rows_plus_one = list(itertools.islice(safe_iter(ds, dataset=dataset), rows_max_number + 1))
File "/src/services/worker/src/worker/utils.py", line 483, in safe_iter
yield from ds.decode(False) if ds.features else ds
File "/usr/local/lib/python3.14/site-packages/datasets/iterable_dataset.py", line 2840, in __iter__
for key, example in ex_iterable:
^^^^^^^^^^^
File "/usr/local/lib/python3.14/site-packages/datasets/iterable_dataset.py", line 2373, in __iter__
for key, pa_table in self._iter_arrow():
~~~~~~~~~~~~~~~~^^
File "/usr/local/lib/python3.14/site-packages/datasets/iterable_dataset.py", line 2398, in _iter_arrow
for key, pa_table in self.ex_iterable._iter_arrow():
~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^
File "/usr/local/lib/python3.14/site-packages/datasets/iterable_dataset.py", line 536, in _iter_arrow
for key, pa_table in iterator:
^^^^^^^^
File "/usr/local/lib/python3.14/site-packages/datasets/iterable_dataset.py", line 419, in _iter_arrow
for key, pa_table in self.generate_tables_fn(**gen_kwags):
~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^
File "/usr/local/lib/python3.14/site-packages/datasets/packaged_modules/json/json.py", line 343, in _generate_tables
self._cast_table(pa_table, json_field_paths=json_field_paths),
~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.14/site-packages/datasets/packaged_modules/json/json.py", line 132, in _cast_table
pa_table = table_cast(pa_table, self.info.features.arrow_schema)
File "/usr/local/lib/python3.14/site-packages/datasets/table.py", line 2378, in table_cast
return cast_table_to_schema(table, schema)
File "/usr/local/lib/python3.14/site-packages/datasets/table.py", line 2306, in cast_table_to_schema
raise CastError(
...<3 lines>...
)
datasets.table.CastError: Couldn't cast
MagneticFieldStrength: double
ImagingFrequency: double
RepetitionTime: double
FlipAngle: int64
Manufacturer: string
ManufacturersModelName: string
PulseSequenceDetails: string
B0_dir: list<item: double>
child 0, item: double
VoxelSize: list<item: double>
child 0, item: double
EchoTime: double
EchoNumber: int64
ImageType: list<item: string>
child 0, item: string
Units: string
to
{'MagneticFieldStrength': Value('float64'), 'ImagingFrequency': Value('float64'), 'RepetitionTime': Value('float64'), 'FlipAngle': Value('int64'), 'Manufacturer': Value('string'), 'ManufacturersModelName': Value('string'), 'PulseSequenceDetails': Value('string'), 'B0_dir': List(Value('float64')), 'VoxelSize': List(Value('float64')), 'EchoTime': Value('float64'), 'EchoNumber': Value('int64'), 'ImageType': List(Value('string'))}
because column names don't matchNeed help to make the dataset viewer work? Make sure to review how to configure the dataset viewer, and open a discussion for direct support.
QSMbly example data
One in-vivo subject, used as the "Load example data" dataset in QSMbly and fetched by the browser at runtime.
A single 5-echo 3D gradient-echo acquisition at 1 mm isotropic, acquired on a Siemens MAGNETOM Prisma Fit. Magnitude and phase are split one file per echo, since QSMbly's loader reads 3D volumes and derives the echo count from the file list.
| Matrix | 184 × 256 × 128, 1 mm isotropic |
| Echoes | 5 — TE 5 / 11 / 17 / 23 / 29 ms |
| TR / flip | 35 ms / 15° |
| Sequence | gre_bridge_1mm_psn_adapt (product GRE, GRAPPA R=2) |
| Scanner | MAGNETOM Prisma Fit (XR VA30A) |
| Phase | radians, wrapped |
Field strength
MagneticFieldStrength is 2.8946 T, the accurate field derived from the scanner's
carrier frequency (ImagingFrequency 123.243444 MHz ÷ 42.576384 MHz/T), not the nominal
3.0 T printed on the magnet. QSM scales ppm by this value, so the accurate one is the
correct one to use.
Echo times
Recovered from the exam-card PDFs shipped with the acquisition and, for the Pulseq consensus sequence in the wider study, from HarmonizedMRI/megre_label. They are not the DICOM sidecar values, which carry placeholder timings for some protocols.
Provenance
Packed from the 2026-08-20 QSM harmonization acquisition (MGH bays 4/5) — one subject
scanned on two Siemens 3T scanners under four protocols × 3 runs. The full study is on
OSF at osf.io/gkemr; this repo holds the prisma-bridge-run1
acquisition only, re-split into per-echo files.
The same acquisition is available to QSMxT users via qsmxt example.
- Downloads last month
- 131