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Prospective parallel randomized trial of the MultiCyte™ ThinPrep® imaging system: the Scottish experience


Dr T. J. Palmer, Department of Pathology, Raigmore Hospital, Inverness, IV2 3UJ, Scotland, UK Tel.: +44 (0)1463 704266; Fax: +44(0)1463 705430; e-mail:


T.J. Palmer, S.M. Nicoll, M.E. McKean, A.J. Park, D. Bishop, L. Baker and J.E.A. Imrie
Prospective parallel randomized trial of the MultiCyte™ ThinPrep® imaging system: the Scottish experience

Background:  Computer-assisted screening of cervical liquid-based cytology (LBC) preparations using the ThinPrep® Imaging System (TIS) has shown improved qualitative and quantitative gains. The use of Multicyte™ has not been described in a well-established national screening programme with a low incidence of high-grade dyskaryosis.

Objectives:  To assess the impact of computer-assisted screening within the Scottish Cervical Screening Programme (SCSP).

Methods:  Two groups of three laboratories, each sharing a ThinPrep® Imager, screened 79 366 slides randomized to test and 90 551 to control arms by laboratory accession. Screeners were not blinded. Standard laboratory reporting profiles of the SCSP, sensitivity, specificity and false-negative rates of all grades of LBC abnormalities with respect to final cytology reports, predictive value for cervical intraepithelial neoplasia grade 2 or worse (CIN2+) on histology; and screening rates were compared for both arms.

Results:  Inadequate and negative reporting rates were significantly lower and low-grade reporting rates significantly higher in the imager arm. Imager-assisted screening showed significantly better specificity than manual screening with respect to the final cytology result. There was no evidence of a significant difference in the detection of CIN2 +  or CIN3 + . Positive, abnormal and total predictive values (high-grade, low-grade and all abnormal cytology found to be CIN2 + , respectively) were similar in both arms. Productivity was significantly higher in the imager arm.

Conclusion:  Computer-assisted screening in a well established screening programme showed significantly improved productivity without loss of quality. These findings should inform future policy for cervical screening programmes.