Brightness and contrast adjustments influence the radiographic detection of soft tissue calcification

Does low bone mineral density have an association with head and neck soft tissue calcifications?

OBJECTIVES

To evaluate whether low bone mineral density (BMD) has an association with the presence of head and neck soft tissue calcifications (STC), aging, and impaired mandibular canal cortices visibility.

MATERIALS AND METHODS

Panoramic radiographs of 1000 women aged between 50 and 75 years old were evaluated by two examiners to classify BMD using mandibular cortical index (C1- normal, C2-moderately eroded and C3-severely eroded), the presence of STC, and also the mandibular canal cortices visibility at the ramus region. Chi-square test evaluated the association between the variables (α = 5%).

RESULTS

There was no association between bone loss and the presence of head and neck soft tissue calcifications, except for calcified thyroid cartilage, which was less visualized at C3 group than others (p < 0.05). Women aged 61 to 70 years old presented higher bone loss than those between 50 and 60 (p < 0.05). The mandibular canal was more poorly visualized at C3 group than C1 and C2 (p < 0.05).

CONCLUSIONS

In general, no association between BMD and the presence of STC was found. However, greater bone loss had a positive correlation with aging and impaired mandibular canal cortices visibility.

CLINICAL RELEVANCE

No relationship between bone mineral density and the existence of soft tissue calcifications was found. Nevertheless, increased bone loss was positively associated with aging and a reduced mandibular canal cortices visibility. This finding highlights the clinical importance of considering bone density factors when planning treatment strategies for patients with related disorders.

Comparison of detection performance of soft tissue calcifications using artificial intelligence in panoramic radiography

Artificial intelligence (AI) is limited to teeth and periodontal disease in the dental field, and is used for diagnosis assistance or data analysis, and there has been no research conducted in actual clinical situations. So, we created an environment similar to actual clinical practice and conducted research by selecting three of the soft tissue diseases (carotid artery calcification, lymph node calcification, and sialolith) that are difficult for general dentists to see. Therefore, in this study, the accuracy and reading time are evaluated using panoramic images and AI. A total of 20,000 panoramic images including three diseases were used to develop and train a fast R-CNN model. To compare the performance of the developed model, two oral and maxillofacial radiologists (OMRs) and two general dentists (GDs) read 352 images, excluding the panoramic images used in development for soft tissue calcification diagnosis. On the first visit, the observers read images without AI; on the second visit, the same observers used AI to read the same image. The diagnostic accuracy and specificity for soft tissue calcification of AI were high from 0.727 to 0.926 and from 0.171 to 1.000, whereas the sensitivity for lymph node calcification and sialolith were low at 0.250 and 0.188, respectively. The reading time of AI increased in the GD group (619 to 1049) and decreased in the OMR group (1347 to 1372). In addition, reading scores increased in both groups (GD from 11.4 to 39.8 and OMR from 3.4 to 10.8). Using AI, although the detection sensitivity of sialolith and lymph node calcification was lower than that of carotid artery calcification, the total reading time of the OMR specialists was reduced and the GDs reading accuracy was improved. The AI used in this study helped to improve the diagnostic accuracy of the GD group, who were not familiar with the soft tissue calcification diagnosis, but more data sets are needed to improve the detection performance of the two diseases with low sensitivity of AI.

Prevalence of soft tissue calcifications in panoramic radiographs of the maxillofacial region of older adults

OBJECTIVES

To investigate the presence of soft tissue calcifications in the head and neck region on panoramic radiographs of older adults.

METHODS

We analysed 1176 panoramic radiographs obtained between January 2013 and December 2018 from individuals of both sexes aged 60 years or older, who were referred by dental specialities to the Dental Imaginology Service of the Federal University of Rio Grande do Norte, Brazil. The types of soft tissue calcification evaluated were as follows: carotid artery calcification (CAC), thyroid cartilage calcifications, triticeous cartilage calcifications, sialoliths, tonsilloliths and lymph node calcifications. The presence of soft tissue calcifications was correlated with age and sex. The chi-square test with continuity correction was used for the calculation of p values and the evaluation of the proposed associations. Prevalence ratios and 95% confidence intervals were also calculated.

RESULTS

At least one type of soft tissue calcification was found in 43% of the sample. The main calcifications detected were CAC, thyroid and triticeous cartilage calcifications, tonsilloliths, sialoliths, calcified lymph nodes, and phleboliths. Mean patient age was 67.47 years and there was a predominance of females (62.8%) in the sample. Bivariate analysis showed a statistically significant association between female sex and the presence of thyroid and triticeous cartilage calcifications and between male sex and the presence of tonsilloliths.

CONCLUSION

Routine panoramic radiography permits the identification of soft tissue calcifications that may be indicators of future cardiovascular disorders, the referral to a medical service and the establishment of therapies for stroke prevention.

Does dose optimisation in digital panoramic radiography affect diagnostic performance?

OBJECTIVES

To compare the overall diagnostic performance of digital panoramic radiographs obtained with low-dose protocols and to estimate the absorbed dose in the head and neck.

MATERIALS AND METHODS

Forty-eight panoramic radiographs were obtained from eight imaging phantoms using six exposure protocols of progressively lower tube voltages (kVp) and currents (mA), as follows: (1) 70 kVp and 12.5 mA, (2) 66 kVp and 10 mA, (3) 66 kVp and 8 mA, (4) 66 kVp and 5 mA, (5) 66 kVp and 4 mA and (6) 66 kVp and 3.2 mA. Five oral radiologists independently evaluated the images and reported all detectable radiographic findings. Intra-examiner reproducibility was assessed by re-evaluation of 25% of the images. The data were analysed using the McNemar and weighted Kappa tests. Absorbed doses of the six protocols were obtained from thermoluminescent dosimeters placed inside a Rando phantom and compared using one-way ANOVA with post hoc Tukey (α = 0.05).

RESULTS

The overall diagnostic performance of panoramic radiographs obtained with low-dose protocols did not differ from that of panoramic radiographs obtained with the highest dose (p > 0.05). Moreover, substantial agreement was observed between all protocols. Protocol 1 resulted in the highest absorbed dose and protocols 4, 5 and 6 in the lowest absorbed doses, with the difference being significant (p ≤ 0.05).

CONCLUSION

Although digital panoramic radiography is considered a relatively low-dose examination, the radiation dose can be further reduced without negatively affecting its overall diagnostic performance.

CLINICAL RELEVANCE

Considering the risks associated with X-rays, digital panoramic radiographs can be obtained at even lower exposure levels.