Digital Pathology Guide for IDC

Digital Pathology Guide for IDC

Tested with: IDC data version v23, idc-index 0.11.9

For general IDC queries and downloads, use idc-index (see main SKILL.md). This guide covers slide microscopy (SM) imaging, microscopy bulk simple annotations (ANN), and segmentations (SEG) in the context of digital pathology in IDC.

Index Tables for Digital Pathology

Five specialized index tables provide curated metadata without needing BigQuery:

All require client.fetch_index("table_name") before querying. Use client.indices_overview to inspect column schemas programmatically.

Slide Microscopy Queries

Basic SM metadata

from idc_index import IDCClient
client = IDCClient()

# sm_index has detailed metadata; join with index for collection_id
client.fetch_index("sm_index")
client.sql_query("""
    SELECT i.collection_id, COUNT(*) as slides,
           MIN(s.min_PixelSpacing_2sf) as min_resolution
    FROM sm_index s
    JOIN index i ON s.SeriesInstanceUID = i.SeriesInstanceUID
    GROUP BY i.collection_id
    ORDER BY slides DESC
""")

Find SM series with specific properties

# Find high-resolution slides with specific objective lens power
client.fetch_index("sm_index")
client.sql_query("""
    SELECT
        i.collection_id,
        i.PatientID,
        s.ObjectiveLensPower,
        s.min_PixelSpacing_2sf
    FROM sm_index s
    JOIN index i ON s.SeriesInstanceUID = i.SeriesInstanceUID
    WHERE s.ObjectiveLensPower >= 40
    ORDER BY s.min_PixelSpacing_2sf
    LIMIT 20
""")

Annotation Queries (ANN)

DICOM Microscopy Bulk Simple Annotations (Modality = 'ANN') are annotations on slide microscopy images. They appear in ann_index (series-level) and ann_group_index (group-level detail). Each ANN series references the slide it annotates via referenced_SeriesInstanceUID.

Basic annotation discovery

# Find annotation series and their referenced images
client.fetch_index("ann_index")
client.fetch_index("ann_group_index")

client.sql_query("""
    SELECT
        a.SeriesInstanceUID as ann_series,
        a.AnnotationCoordinateType,
        a.referenced_SeriesInstanceUID as source_series
    FROM ann_index a
    LIMIT 10
""")

Annotation group statistics

# Get annotation group details (graphic types, counts, algorithms)
client.sql_query("""
    SELECT
        GraphicType,
        SUM(NumberOfAnnotations) as total_annotations,
        COUNT(*) as group_count
    FROM ann_group_index
    GROUP BY GraphicType
    ORDER BY total_annotations DESC
""")

Find annotations with source slide context

# Find annotations with their source slide microscopy context
client.sql_query("""
    SELECT
        i.collection_id,
        g.GraphicType,
        g.AnnotationPropertyType_CodeMeaning,
        g.AlgorithmName,
        g.NumberOfAnnotations
    FROM ann_group_index g
    JOIN ann_index a ON g.SeriesInstanceUID = a.SeriesInstanceUID
    JOIN index i ON a.referenced_SeriesInstanceUID = i.SeriesInstanceUID
    WHERE g.AlgorithmName IS NOT NULL
    LIMIT 10
""")

Segmentations on Slide Microscopy

DICOM Segmentations (Modality = 'SEG') are used for both radiology (e.g., organ segmentations on CT) and pathology (e.g., tissue region segmentations on whole slide images). Use seg_index.segmented_SeriesInstanceUID to find the source series, then filter by source Modality to isolate pathology segmentations.

# Find segmentations whose source is a slide microscopy image
client.fetch_index("seg_index")
client.fetch_index("sm_index")
client.sql_query("""
    SELECT
        seg.SeriesInstanceUID as seg_series,
        seg.AlgorithmName,
        seg.total_segments,
        src.collection_id,
        src.Modality as source_modality
    FROM seg_index seg
    JOIN index src ON seg.segmented_SeriesInstanceUID = src.SeriesInstanceUID
    WHERE src.Modality = 'SM'
    LIMIT 20
""")

Filter by AnnotationGroupLabel

AnnotationGroupLabel is the most direct column for finding annotation groups by name or semantic content. Use LIKE with wildcards for text search.

Simple label filtering

# Find annotation groups by label (e.g., groups mentioning "blast")
client.fetch_index("ann_group_index")
client.sql_query("""
    SELECT
        g.SeriesInstanceUID,
        g.AnnotationGroupLabel,
        g.GraphicType,
        g.NumberOfAnnotations,
        g.AlgorithmName
    FROM ann_group_index g
    WHERE LOWER(g.AnnotationGroupLabel) LIKE '%blast%'
    ORDER BY g.NumberOfAnnotations DESC
""")

Label filtering with collection context

# Find annotation groups matching a label within a specific collection
client.fetch_index("ann_index")
client.fetch_index("ann_group_index")
client.sql_query("""
    SELECT
        i.collection_id,
        g.AnnotationGroupLabel,
        g.GraphicType,
        g.NumberOfAnnotations,
        g.AnnotationPropertyType_CodeMeaning
    FROM ann_group_index g
    JOIN ann_index a ON g.SeriesInstanceUID = a.SeriesInstanceUID
    JOIN index i ON a.SeriesInstanceUID = i.SeriesInstanceUID
    WHERE i.collection_id = 'your_collection_id'
      AND LOWER(g.AnnotationGroupLabel) LIKE '%keyword%'
    ORDER BY g.NumberOfAnnotations DESC
""")

Annotations on Slide Microscopy (SM + ANN Cross-Reference)

When looking for annotations related to slide microscopy data, use both SM and ANN tables together. The ann_index.referenced_SeriesInstanceUID links each annotation series to its source slide.

# Find slide microscopy images and their annotations in a collection
client.fetch_index("sm_index")
client.fetch_index("ann_index")
client.fetch_index("ann_group_index")
client.sql_query("""
    SELECT
        i.collection_id,
        s.ObjectiveLensPower,
        g.AnnotationGroupLabel,
        g.NumberOfAnnotations,
        g.GraphicType
    FROM ann_group_index g
    JOIN ann_index a ON g.SeriesInstanceUID = a.SeriesInstanceUID
    JOIN sm_index s ON a.referenced_SeriesInstanceUID = s.SeriesInstanceUID
    JOIN index i ON a.SeriesInstanceUID = i.SeriesInstanceUID
    WHERE i.collection_id = 'your_collection_id'
    ORDER BY g.NumberOfAnnotations DESC
""")

Join Patterns

SM join (slide microscopy details with collection context)

client.fetch_index("sm_index")
result = client.sql_query("""
    SELECT i.collection_id, i.PatientID, s.ObjectiveLensPower, s.min_PixelSpacing_2sf
    FROM index i
    JOIN sm_index s ON i.SeriesInstanceUID = s.SeriesInstanceUID
    LIMIT 10
""")

ANN join (annotation groups with collection context)

client.fetch_index("ann_index")
client.fetch_index("ann_group_index")
result = client.sql_query("""
    SELECT
        i.collection_id,
        g.AnnotationGroupLabel,
        g.GraphicType,
        g.NumberOfAnnotations,
        a.referenced_SeriesInstanceUID as source_series
    FROM ann_group_index g
    JOIN ann_index a ON g.SeriesInstanceUID = a.SeriesInstanceUID
    JOIN index i ON a.SeriesInstanceUID = i.SeriesInstanceUID
    LIMIT 10
""")

Related Tools

The following tools work with DICOM format for digital pathology workflows:

Python Libraries:

• highdicom - High-level DICOM abstractions for Python. Create and read DICOM Segmentations (SEG), Structured Reports (SR), and parametric maps for pathology and radiology. Developed by IDC.
• wsidicom - Python package for reading DICOM WSI datasets. Parses metadata into easy-to-use dataclasses for whole slide image analysis.
• TIA-Toolbox - End-to-end computational pathology library with DICOM support via DICOMWSIReader. Provides tile extraction, feature extraction, and pretrained deep learning models.
• EZ-WSI-DICOMweb - Extract image patches from DICOM whole slide images via DICOMweb. Designed for AI/ML workflows with cloud DICOM stores.

Viewers:

• Slim - Web-based DICOM slide microscopy viewer and annotation tool. Supports brightfield and multiplexed immunofluorescence imaging via DICOMweb. Developed by IDC.
• QuPath - Cross-platform open source software for whole slide image analysis. Supports DICOM WSI via Bio-Formats and OpenSlide (v0.4.0+).

Conversion:

• dicom_wsi - Python implementation for converting proprietary WSI formats to DICOM-compliant files.