Case presentation of oral soft tissue lesions by using ultrasound, terahertz and histopathology

Background

In recent years, there has been an intense interest in biomedical imaging applications based on terahertz (THz) wavelengths due to its advantages such as non-invasiveness and non-ionizing radiation.

Case Presentation and Differential Diagnosis

A total of 10 intraoral lesions were evaluated by using an ACUSON S 2000 (Siemens, Munchen, Germany) color Doppler ultrasonography unit with a 15 MHz intraoperative probe. The borders of the lesion, vascular supply, and internal structure were evaluated. After ultrasonography, excision of lesions was performed under local anesthesia and histopathological examination and spectroscopy by using Terahertz Attenuated Total Reflection (ATR) in the light were performed. On ultrasonographic examination, 6 of the lesions showed a heterogeneous hyperechogenicity with well-defined margins and posterior acoustic shadow with no vascularity. The lesions were diagnosed histopathologically as fibroma with hyperkeratosis, hyperplasia of epidermis, proliferation of fibroblasts, and hyaline degeneration in partially hyperplastic collagen. Three of these lesions were hypoechoic with well-defined hyperechoic borders, with some isoechoic areas indicating internal vascularization. These lesions were histopathologically diagnosed as peripheral giant cell granuloma showing epithelioid cells and macrophages. One lesion showed a heterogeneous echogenic internal structure with clear hyperechoic borders without vascularization on ultrasonographic evaluation. This was histopathologically diagnosed as oral focal mucinosis, appearing as well-circumscribed but non-encapsulated myxomatous connective tissue. Imaging characteristics of the 10 lesions were shown by using the terahertz method with our laboratory settings.

Conclusion

Terahertz images were found to be promising in terms of assessing intraoral soft tissue lesions. Statement of Ethical Review Written consent and permission was obtained from the patients