Diagnostic Accuracy of Cystic Lesions Using a Pre-Programmed Low-Dose and Standard-Dose Dental Cone-Beam Computed Tomography Protocol: An Ex Vivo Comparison Study

Abstract

Background: This study aimed to analyze the diagnostic reliability of radiographic assessment of cystic lesions using a pre-set, manufacturer-specific, low-dose mode compared to a standard-dose dental cone-beam computed tomography (CBCT) imaging protocol.

Methods: Forty pig mandible models were prepared with cystic lesions and underwent both CBCT protocols on an Orthophos SL Unit (Dentsply-Sirona, Bensheim, Germany). Qualitative and quantitative analysis of CBCT data was performed by twelve investigators independently in SIDEXIS 4 (Dentsply-Sirona) using a trial-specific digital examination software tool. Thereby, the effect of the two dose types on overall detectability rate, the visibility on a scale of 1 (very low) to 10 (very high) and the difference between measured radiographic and actual lesion size was assessed.

Results: Low-dose CBCT imaging showed no significant differences considering detectability (78.8% vs. 81.6%) and visibility (9.16 vs. 9.19) of cystic lesions compared to the standard protocol. Both imaging protocols performed very similarly in lesion size assessment, with an apparent underestimation of the actual size.

Conclusion: Low-dose protocols providing confidential diagnostic evaluation with an improved benefit-risk ratio according to the ALADA principle could become a promising alternative as a primary diagnostic tool as well as for radiological follow-up in the treatment of cystic lesions.

Keywords: cone-beam computed tomography; cystic lesion; low dose protocols; low-dose cone-beam computed tomography; oral anatomy; oral surgery.

Figure 1

Special drilling instruments (rose head bur H141, Komet Dental, DENTAL Brasseler GmbH, Lemgo, Germany; handpiece Kavo Expertmatic E10C, KaVo Dental AG, Kloten, Switzerland) were used to prepare (A) lingual and (B) buccal mandibular cystic lesions of the same size after partial removal of soft tissue and epithelium and underwent standard and low-dose CBCT imaging protocols.

Figure 2

Detectability rates (percentage) of the cystic lesions in the low dose (LD) and standard-dose (SD) imaging protocol. The detection of cystic lesions was successful in 78.8% of cases with the low-dose protocol and in 81.6% with the standard protocol.

Figure 3

The qualitative analysis of the visibility of cystic lesions according to the dose mode using a scale from 1 (very low) to 10 (very high). Regarding the visibility of cystic lesions, an average value of 9.16 in low dose protocol and 9.19 in standard-dose protocol was registered.

Figure 4

Screenshots of the cystic lesions visualized using the standard-dose (upper row) (image reconstruction (A), axial (C), and coronal (E)) and low-dose (lower row) (image reconstruction (B), axial (D), and coronal (F)) cone-beam computed tomography (CBCT) imaging protocols.

Figure 5

A Wilcoxon signed-rank test with continuity correction was performed based on a significance level of 5% to investigate whether the imaging protocols showed significant differences in their assessment with regard to lesion size. The difference between the measured and actual size of the lesion at its greatest extent in both imaging protocols is visualized. Both imaging protocols were found to perform very similarly with no statistically significant differences (p = 0.46) and with an apparent underestimation of the actual distance in both the low-dose and standard protocols.