Comparison of manual and automated digital image analysis systems for quantification of cellular protein expression.

OBJECTIVE: Quantifying protein expression in immunohistochemically stained histological slides is an important tool for oncologic research. The use of computer-aided evaluation of IHC-stained slides significantly contributes to objectify measurements. Manual digital image analysis (mDIA) requires a user-dependent annotation of the region of interest (ROI). Others have built-in machine learning algorithms with automated digital image analysis (aDIA) and can detect the ROIs automatically. We aimed to investigate the agreement between the results obtained by aDIA and those derived from mDIA systems. METHODS: We quantified chromogenic intensity (CI) and calculated the positive index (PI) in cohorts of tissue microarrays (TMA) using mDIA and aDIA. To consider the different distributions of staining within cellular sub-compartments and different tumor architecture our study encompassed nuclear and cytoplasmatic stainings in adenocarcinomas and squamous cell carcinomas. RESULTS: Within all cohorts, we were able to show a high correlation between mDIA and aDIA for the CI (p<0.001) along with high agreement for the PI. Moreover, we were able to show that the cell detections of the programs were comparable as well and both proved to be reliable when compared to manual counting. CONCLUSION: mDIA and aDIA show a high correlation in acquired IHC data. Both proved to be suitable to stratify patients for evaluation with clinical data. As both produce the same level of information, aDIA might be preferable as it is time-saving, can easily be reproduced, and enables regular and efficient output in large studies in a reasonable time period.

Retrospective analysis of time-related three-dimensional iliac bone graft resorption following sinus lift and vertical augmentation in the maxilla.

The atrophic maxilla frequently requires bone grafting using an onlay graft (OG) or sinus lifting (SL) before implant rehabilitation. The resorption of bone grafts is influenced by the time until implantation, quality of donor bone, and grafting technique. The aim of this study was to investigate the impact of both grafting techniques on the time-related resorption of autologous iliac bone graft. Forty-three patients underwent either onlay grafting or a sinus lift at 73 sites in the maxilla. Graft height was measured by cone beam computed tomography after augmentation and during follow-up for up to 12 months prior to implant insertion. The effect of time and technique on graft resorption was evaluated retrospectively. The reduction in bone graft height was greater for OG than SL over the investigated time intervals (OG = 51%, SL = 28%; P = 0.002). Each technique followed a specific course of resorption, which was independent of the initial graft height and could be calculated by a non-linear regression model. Iliac bone graft undergoes rapid resorption when used as an OG prior to implant insertion. For SL, this resorption is reasonably lower. This is especially crucial to determine the optimal time for implant insertion after graft healing to improve implant survival.