Influence of VistaScan image enhancement filters on diagnosis of simulated periapical lesions on intraoral radiographs

OBJECTIVE:

To evaluate whether image enhancement filters of VistaScan system improve the diagnostic accuracy of simulated periapical lesions.

METHODS:

10 sockets were prepared on bovine ribs to fit a bovine tooth. Bone defects were created and successively enlarged providing four groups (n = 10): Group 0, absence of lesions; Group 1, periapical lesions with 1.6  mm in diameter; Group 2, with 1.8  mm in diameter; and Group 3, with 2.1  mm in diameter. Periapical radiographs were taken using a photostimulable storage phosphor plate and DBSWIN software. VistaScan filters were applied and the images were allocated into seven groups: Nonfiltered, Fine, Caries 1, Caries 2, Endodontic, Periodontal and Noise Reduction. All the 280 images were assessed about the presence or absence of periapical lesions. Pixel intensities standard deviation were compared between nonfiltered and filtered images. Two-Way Analysis of Variance and the post hoc Tukey's test were used to compare area under the ROC curve, sensitivity and specificity.

RESULTS:

VistaScan filters showed no significant difference for area under receiver operating characteristic curve (p = 0.124), sensitivity (p = 0.835) and specificity (p = 0.832). Area under receiver operating characteristic curve (p = 0.000) and sensitivity (p = 0.000) in 2.1  mm lesions size were significantly higher than in 1.6  mm and 1.8  mm lesions size. Pixel intensities standard deviation was significantly changed in the filtered images compared to nonfiltered ones (p < 0.01), except for Fine in the bone region (p > 0.05).

CONCLUSION:

VistaScan enhancement filters do not influence the diagnostic accuracy of simulated periapical lesions. On the other hand, larger lesions were more frequently detected. The filters change the pixel intensities reducing or intensifying the differences between similar regions.