added description

SPIDER.py

@@ -11,7 +11,27 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-"""TODO: Add a description here.""" #TODO
+"""The SPIDER dataset contains (human) lumbar spine magnetic resonance images 
+(MRI) and segmentation masks described in the following paper:
+
+van der Graaf, J.W., van Hooff, M.L., Buckens, C.F.M. et al. Lumbar spine 
+segmentation in MR images: a dataset and a public benchmark. 
+Sci Data 11, 264 (2024). https://doi.org/10.1038/s41597-024-03090-w
+
+The dataset includes 447 sagittal T1 and T2 MRI series collected from 218 
+patients across four hospitals. Segmentation masks indicating the vertebrae, 
+intervertebral discs (IVDs), and spinal canal are also included. Segmentation 
+masks were created manually by a medical trainee under the supervision of a 
+medical imaging expert and an experienced musculoskeletal radiologist.
+
+In addition to MR images and segmentation masks, additional metadata 
+(e.g., scanner manufacturer, pixel bandwidth, etc.), limited patient 
+characteristics (biological sex and age, when available), and radiological 
+gradings indicating specific degenerative changes can be loaded with the 
+corresponding image data.
+
+HuggingFace repository: https://huggingface.co/datasets/cdoswald/SPIDER
+""" 
 
 # Import packages
 import csv