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Objective: Various modalities are applied for pathological diagnosis of malignant biliary strictures (MBS), including brush cytology (BC), forceps biopsy (FB) and endoscopic ultrasound‐guided fine needle aspiration (EUS‐FNA). We aimed to assess the value of these modalities in a repeated tissue acquisition process for biliary strictures with initially inconclusive pathological outcomes. Methods: Patients who were suspected of having MBS and underwent a BC in two large teaching hospitals were retrospectively included. The sensitivity, specificity, positive and negative predictive values, and accuracy of the initial and repeated BC, FB and EUS‐FNA were analyzed. Their performances were compared to determine which modality was superior in repeated tissue acquisition. Results: In total, 476 patients were included. The sensitivity, specificity and accuracy in diagnosing MBS for the initial BC were 30.3%, 100% and 55.0%, respectively. Altogether 39, 27 and 44 patients underwent a repeat BC, FB and EUS‐FNA, respectively. The sensitivity for repeated BC, FB and EUS‐FNA was 41.2%, 61.1% and 44.4%, respectively, whereas their specificity all reached 100%. When comparing diagnostic accuracy, none of the modalities was superior (74.4% vs 74.1% vs 54.5%, P = 0.173). In the repeated process, one patient who underwent BC and two underwent FB developed mild pancreatitis. Conclusions: Repeated tissue acquisition achieves a conclusive diagnosis of MBS in nearly half patients who have an initially inconclusive cytological diagnosis. None of the tissue acquisition methods is significantly superior in the repeated process. [ABSTRACT FROM AUTHOR]

The crystal structures of N, N′-(1,2-phenyl­ene)­bis­(pyridine-2-carbox­amide), C18H14N4O2, (I), and N, N′-(1,2-cyclo­hexane­diyl)­bis­(pyridine-2-carbox­amide) have been determined, the latter compound as the toluene hemisolvate, C18H20N4O2·0.5C7H8, (II). In (I), the benzene ring is nearly coplanar with one of the pyridine rings and forms a dihedral angle of 59.4 (1)° with the other. However, in (II), the dihedral angle of the two pyridine rings is 70.0 (1)°. [ABSTRACT FROM AUTHOR]