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The Effects of Compression Factor on Special Stains Whole Slide Imaging. Anurag Sharma 1 , Mark Merren 2 , Pinky Bautista 2 , Roy Lee 2 and Yukako Yagi 2. 1 NEC Laboratories America, Inc. 2 Massachusetts General Hospital. (Pathology Imaging & Comm. Tech. Center). Objective.
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The Effects of Compression Factor on Special Stains Whole Slide Imaging Anurag Sharma1, Mark Merren2, Pinky Bautista2, Roy Lee2 and Yukako Yagi2 1 NEC Laboratories America, Inc. 2 Massachusetts General Hospital. (Pathology Imaging & Comm. Tech. Center)
Objective • To find appropriate compression for special stains in high volume Whole Slide Imaging (WSI) • To investigate the balance between quality and compression
Background – WSI WSI – Tasks and Expectations
Background – Image Compression Compression: Quality Factor (QF) • No universal definition • Indicator of the image quality • Inversely proportional to the compression • Most scanners can be configured to change QF • QF 100 being the best quality image • Higher QF has higher infrastructure requirements • QF varies from manufacturer to manufacturer • Only factor user can control
Effect of QF on Image Size Quality versus size Image size and quality both get reduced with lower QF
Why Special Stains • Earlier, we conducted a similar study with H&E where QF80 was found acceptable • Color distribution is more important than morphology • Special stains may work with higher compression • 10-15% of slides/day is Special stain
Material PAS-D Elastic GMS Congo Red Reticulin PAS Mucicarmine Eight slides from Set I Trichrome
Material Giemsa BrownHopps-Gram PAS Warthin-Starry Steiner GMS Trichrome Reticulin Eight slides from Set 2
Method • Eight slides of mouse embryo • Eight slides of human tissue • Twelve stains • Three scanners • Total Images – 208 • Resolution 0.33-0.50 µm/pixel • Reviewed by a pathologist and 4 non-pathologists including an imaging specialist • reviewed a calibrated monitor • Uncompressed (TIFF) • QF 90, 80, 70, 50, 30 (JPEG)
Results: • Image quality was clearly affected by compression lower than QF 50 • However this did not influence the evaluation with special stain • Most stains were acceptable with QF 30 except Reticulin • All stains showed lighter contrast with compression. (higher compression -> lower contrast)
Results - Mouse Embryo QF 90
Results - Mouse Embryo QF 30
Results - Reticulin Bone Marrow – Hypocellular marrow with triline age hematopoiesis
Results - Reticulin QF 70 QF 90 QF 50 QF 30 Liver Core Biopsy
Results - Trichrome Endocardium Biopsy (right ventricle)
Results - PAS/D QF 30 QF 90 Renal Cell Carcinoma
Results - PAS/D Quality degradation from QF 90 to QF 30 QF 90
Results: • Special stain images of acceptable quality at QF 30 • QF 50 for Reticulin • Artifacts visibility is high at lower QFs • Significant reduction in resources • scan time • storage space • image viewing
Conclusion and discussion • Though the QF 30 provided acceptable image quality for most special stains, some stains worked at QF 50. Hence, a setting of QF 50 is found suitable for volume WSI scans. Future works: • Quantitative analysis of the image quality • Similar study in Immuno-stains