New image‐processing technology for endoscopic ultrasound‐guided fine‐needle aspiration biopsy specimen evaluation in patients with pancreatic cancer

OBJECTIVES: We evaluated the usefulness of a newly developed system with which the total amount of whitish cores in endoscopic ultrasound‐guided fine‐needle aspiration biopsy (EUS‐FNAB) samples is automatically calculated (automated multiband imaging system [AMUS]). METHODS: From 30 prospectively enrolled patients suspected of having pancreatic cancer, four EUS‐FNAB specimens per patient were obtained. Following AMUS calculations, two specimens were prepared after stereomicroscopy‐guided manual division into whitish and reddish sections (isolation group), and the other two were prepared without such division (no‐isolation group). The relation of the AMUS results pertaining to the length of the manually measured whitish cores (stereo‐microscopically visible white core [SVWC]) and the sample suitability for pathologic evaluation were analyzed. RESULTS: Histological diagnostic accuracy was 90%; median SVWC length, 14 mm; and median area of whitish core calculated using the AMUS, 13 mm(2). The SVWC length correlated with whitish core amount (ρ = 0.83, p < 0.01) and adequacy score (ρ = 0.50, p < 0.01). The whitish core amount correlated with the adequacy score (ρ = 0.40, p < 0.01). The area under the receiver‐operating characteristic curve calculated for whitish core amount with respect to the histological diagnosis was 0.84 (p < 0.01; cutoff ≥ 8 mm(2), sensitivity 92.5%). Subgroup analysis (isolation vs. no‐isolation group) revealed no significant between‐group differences in the median histological adequacy (p = 0.27) or tumor cell content ratio (p = 0.28). The median scores for degree of blood contamination were significantly lower in the isolation group than in the no‐isolation group (p < 0.01). CONCLUSION: AMUS is a simple on‐site verification procedure for determining the appropriate sampling tissue quantity for high diagnostic accuracy.