Comparison of quantitative radiomorphometric predictors of healthy and MRONJ-affected bone using panoramic radiography and cone-beam CT

Abstract

Objectives: To determine the most distinctive quantitative radiomorphometric parameter(s) for the detection of MRONJ-affected bone changes in panoramic radiography (PR) and cone-beam CT (CBCT).

Methods: PR and sagittal CBCT slices of 24 MRONJ patients and 22 healthy controls were used for the measurements of mandibular cortical thickness (MCT), fractal dimension (FD), lacunarity, mean gray value (MGV), bone area fraction (BA/TA), trabecular thickness (Tb.Th), trabecular separation (Tb.Sp), trabecular number (Tb.N). MCT was measured in the mental foramen region. While FD and lacunarity were measured on mandibular trabecular and cortical regions-of-interest (ROIs), the remaining parameters were measured on trabecular ROIs. The independent samples t-test was used to compare the measurements between the MRONJ and control groups for both imaging modalities (P = .05).

Results: MCT was the only parameter that differentiated MRONJ-affected bone in both PR and CBCT (P < .05). None of the remaining parameters revealed any difference for MRONJ-affected bone in CBCT (P > .05). FD, lacunarity, MGV, BA/TA, and Tb.Sp could distinguish MRONJ-affected trabecular bone in PR (P < .05). The correspondent ROI for both imaging methods that was reliable for detecting MRONJ-affected bone was the trabecular bone distal to the mental foramen above the inferior alveolar canal (ROI-3).

Conclusions: MCT is a reliable parameter for the discrimination of MRONJ-affected bone in both PR and CBCT images. PR may be used to detect MRONJ-affected trabecular bone using FD, lacunarity, MGV, BA/TA, and Tb.Sp measurements as well.

Keywords: cone-beam CT; medication-related osteonecrosis of the jaws; panoramic radiography; quantitative bone parameters.

Figure 1.

(A) The bucco-lingual line connecting the outer borders of buccal and lingual cortical walls of the mandible and passing through the centre of the mental foramen on axial slice (horizontal line). (A, B) The sagittal plane passing through the midpoint of the buccal and lingual cortical plates of the mandible on axial and coronal slices (vertical line). (C) The resulting sagittal plane for locating the ROI(s).

Figure 2.

Locations of trabecular and cortical ROIs in PR and sagittal CBCT images. (A) PR and (B) CBCT images showing trabecular ROIs anterior to the mental foramen (ROI-1), inferior to the mental foramen (ROI-2), and distal to the mental foramen above the inferior alveolar canal (ROI-3). (C) PR and (D) CBCT images showing cortical ROIs inferior to the mental foramen (ROI-4), and between the distal border of the mental foramen to the ascending ramus (ROI-5).

Figure 3.

Measurement of MCT in PR and three sagittal CBCT slices. (A) PR image of the hemi-mandible showing the perpendicular line drawn to the tangent line to the inferior border. (B, B1) Measurement of MCT in the sagittal CBCT slice passing through the midpoint of the buccal and lingual cortical plates of the mandible, and the sagittal slices. (C, C1) 2 mm to the buccal, and (D, D1) 2 mm to the lingual to the middle slice. MCT was measured in the inferior part of the perpendicular line (white lines) for PR and each CBCT slice.

Figure 4.

(A) Trabecular ROI cropped from the original image before binarization, (B) segmented binarized ROI showing bone trabeculae (black pixels) and bone marrow (white pixels), (C) graphical illustration of segmented image describing Tb.Th (α) and Tb.Sp (β).