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| ORIGINAL ARTICLE |
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| Year : 2021 | Volume
: 9
| Issue : 1 | Page : 20-25 |
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The use of ultrasonography in oral radiology: An ultrasound archive study
Fatma Caglayan, Fatma Nur Yozgat İlbaş, Betül Subaşı Aksakal
Department of Oral Dental and Maxillofacial Radiology, Faculty of Dentistry, Ataturk University, Erzurum, Turkey
| Date of Submission | 18-Mar-2021 |
| Date of Decision | 04-Apr-2021 |
| Date of Acceptance | 07-Apr-2021 |
| Date of Web Publication | 20-May-2021 |
Correspondence Address:
Fatma Caglayan
Department of Oral Dental and Maxillofacial Radiology, Faculty of Dentistry, Ataturk University, Erzurum 25240
Turkey
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/jomr.jomr_6_21
Objective: The objective was to evaluate the ultrasonography (USG) images and reports in dental and maxillofacial radiology clinic, to reveal USG usage, and to draw attention to the diagnostic contribution of USG in necessary cases. Materials and Methods: USG archive has been reviewed retrospectively. One hundred and eleven USG examinations reported in our clinic between 2016 and 2020 were included in the study. USG patients consisted of 57 males and 54 females and their mean age was 38.76 ± 18.60. Results: The use of USG in the dental radiology clinic was not satisfactory since only 111 USG examinations were detected. Extraoral USG was used in 64.9%, intraoral USG in 28.8%, and both extraoral and intraoral USG in 6.3% of patients. The most frequently used areas of USG were lymph node examinations (26.1%), mucosal lesions (18.9%), salivary gland pathologies (16.2%), abscesses (10.8%), nasolabial cysts (4.5%), masseter hypertrophy (2.7%), palatal masses (2.7%), and others (6.3%). Conclusion: Despite advantages of USG in soft-tissue pathologies and even in some jaw pathologies, its use in dental radiology is limited. Dental and maxillofacial radiologists should improve themselves in the use of USG and follow the developments and also should be aware of the benefits that
Keywords: Abscess, lymph node, salivary glands, ultrasonography
How to cite this article:
Caglayan F, Yozgat İlbaş FN, Aksakal BS. The use of ultrasonography in oral radiology: An ultrasound archive study. J Oral Maxillofac Radiol 2021;9:20-5 |
How to cite this URL:
Caglayan F, Yozgat İlbaş FN, Aksakal BS. The use of ultrasonography in oral radiology: An ultrasound archive study. J Oral Maxillofac Radiol [serial online] 2021 [cited 2023 Mar 20];9:20-5. Available from: https://www.joomr.org/text.asp?2021/9/1/20/316486 |
| Introduction | |  |
Modern dental radiology now uses conventional radiography techniques as well as advanced imaging methods such as computed tomography (CT), magnetic resonance imaging (MRI), and ultrasonography (USG). Today, the most commonly used advanced imaging technique in dental radiology is cone-beam computed tomography (CBCT) and the CBCT device is generally included in almost all dental radiology units. Now, the use of USG in the field of dental radiology is getting increasing interest and the dental radiology departments have USG devices within their body.
USG is a diagnostic method in which internal organs are imaged using ultrasound in medicine. The basic principles and applications of ultrasound were first discovered by the Curie brothers in 1880, and USG imaging was described by the Dussik brothers in 1937.[1] In 1963, Baum et al. reported the diagnostic USG findings in dentistry first time.[2] The sound waves used in USG are not electromagnetic, unlike X-rays. Therefore, there is no risk of X-ray and ionizing radiation in this examination method and it can be used easily even in pregnant and children. Ultrasonic images are created by sending ultrasound waves to the tissue from elements called transducers that convert electrical energy into ultrasonic sound waves by the piezoelectric effect. Heads carrying the transducer in USG devices are called probes. Depending on the shape, frequency, and configuration of the probe, different viewing areas are created. In the USG principle, low frequency results in deeper tissue penetrance but lower image resolution.[3] Since the structures to be examined in dentistry are relatively superficial, high-frequency linear probes are used. Convex probes are generally used in abdominal examinations and gynecology where deep penetration is required because of their low frequency.
Muscles, tendons, joints, vessels, and internal organs that are not behind the bone can be examined with USG. The echoes obtained in USG depending on the location and amplitude differences are displayed in three different modes: A (amplitude), B (brightness), and M (motion).[4] B-mode is the most commonly used method in diagnostic radiology, and B-mode creates two-dimensional images consisting of points of different brightness in the gray scale on the monitor. Doppler USG, the basic method for assessing the quality and quantity of blood flow, was developed by Australian physicist Johan Christian Doppler in 1842.[5]
Compared to other medical imaging methods, USG has a number of advantages, namely creates simultaneous images, portable, relatively inexpensive, does not have the risk of ionizing radiation, noninvasive, and unaffected by metal artifacts such as dental restorations.[1],[2],[6] With its power Doppler and Color Doppler features, it enables to examine the vascularization of lesions, distinguish between cystic and solid lesions, and helps to distinguish malignant and benign lesions.[1],[6] USG also has some disadvantages such as there may be limitations in the examination area depending on the physical condition and cooperation of the patient and images cannot be obtained from the structures behind the bone and air; the success of the method largely depends on the success of the operator. Oral and nasal cavities, pharynx, larynx, and trachea regions are almost completely filled with air and many bone barriers in these areas make USG examination difficult in the maxillofacial area.[3],[7] Since ultrasound is blocked by the bone, images can be obtained from the back of the bone only when there is a perforation area in the bone that will allow the passage of ultrasound waves.
Although it is thought that the use of USG in dentistry is limited to evaluation of salivary glands, cervical lymph node evaluation, facial muscles, and soft tissues of the face and neck, with the development of high-resolution devices in recent years, USG has started to be used in different areas in our field. High-resolution images can be obtained in many planes in the maxillofacial region with modern USG devices combined with high frequency (7.5–12 MHz) linear probes. In dentistry, USG is generally used in the imaging of maxillofacial fractures,[8] cervical lymphadenopathy,[9],[10] various soft-tissue masses,[10] masticatory and neck muscles,[11] temporomandibular joint (TMJ),[12] periapical lesions,[13] and of course salivary gland diseases.[14] Transoral or transcutaneous approach is preferred in USG examinations in dental radiology according to the case. Intraoral USG is also used for examining the salivary glands and ducts, as well as the mouth floor, the buccal, labial, and palatal mucosa, the tongue, periodontal tissues, and periapical lesions.[15]
The aim of this study was to re-evaluate the USG images and reports in our clinic and to reveal USG usage in our dental and maxillofacial radiology department. In this way, it was also aimed to reveal the deficiencies of using USG in the field of dental radiology and to draw attention to the diagnostic contribution of USG in necessary cases.
| Materials and Methods | | |
This study was carried out in the department of oral and maxillofacial radiology and is approved by the faculty ethical committee in compliance with the Helsinki Declaration (Decision number: 2020/41). One hundred and eleven USG reports performed in our radiology clinic between 2016 and 2020 were included in the study. Only the USG results that were clinically requested and the result reports entered into the system were included in the study. Apart from this, USG images taken for academic studies were not included in the study. USG patients consisted of 57 males and 54 females and their mean age was 38.76 ± 18.60 (minimum: 4, maximum: 80) years. USG examinations were performed together with assistant dental and maxillofacial radiologists and master hold PhD with at least 5 years of maxillofacial USG experience. Evaluations were performed by the master. In suspicious cases, both the patient reports and images were re-examined and she made the final decision again. USG was applied using an Aplio-300 device (Toshiba Corporation, Tokyo, Japan) and a 7.5 MHz and 12 MHz linear probe for transcutaneous USG and 18 MHz hockey stick probe for intraoral USG.
Demographic data of the patients were recorded. USG reports and images of the patients were examined retrospectively one by one again. The probe used and the method of intraoral or extraoral USG examination were recorded also. USG results were classified as: salivary gland diseases such as sialoliths, tumors, infections, and others; lymphadenopathy; abscess; mucosal lesions; jaw lesions; masseter examination; and others.
The data were evaluated using the SPSS V. 20.0 program. Distribution and frequencies were determined.
| Results | | |
A total of 111 reported USG scans were included in the study. Demographic data of the patients included in the study were as follows: 57 males and 54 females and the mean age was 38.76 ± 18.60 (min: 4, maximum: 80) years. When the USG technique used was evaluated, extraoral USG was used in 72 (64.9%) patients, intraoral USG in 32 (28.8%) patients, and both extraoral and intraoral USG in 7 (6.3%) patients.
The distribution of pathologies examined by USG is seen in [Table 1]. The most common use of USG was lymph node examination (26.1%) [Figure 1]. Of the patients for whom lymphadenopathy was evaluated, 29 had facial, 12 had submandibular, 3 had cervical, and 2 had submental lymphadenopathy and all of them were examined by extraoral USG. | Figure 1: (a and b) Two examples of lymph node examination. (a) A facial node anterior the masseter muscle with hilar blood flow on colored Doppler ultrasonography. (b) A parotideal lymph node with echogenic hilus
Click here to view |
Second, USG was used most frequently in the examinations of mucosal lesions [18.9%, [Figure 2]. The first two of the most common mucosal lesions were mucosal hemangioma in eight patients and superficial mucoceles in five patients. Third, USG was used most frequently in the examinations of major salivary glands [16.2%, [Figure 3]. The most common finding in the salivary glands was sialolith (10.8%), solid masses (3.6%), and salivary gland infection (1.8%). Extraoral USG was used in all salivary gland examinations except the only case of sublingual stone. | Figure 2: A hemangioma on the dorsal of the tongue with increased blood flow by color Doppler ultrasonography
Click here to view |
 | Figure 3: (a-d) Examples for salivary gland pathologies. (a) A panoramic view of a suspected submandibular sialolith. (b) Ultrasonography examination of the same patient reveals a hyperechogenic stone with posterior acoustic shadow and loss of parenchymal echogenicity of the submandibular gland. (c) A cystic lesion (ranula) with posterior acoustic enhancement on the mouth floor. (d) A case of chronic infection (sialadenitis) of the parotid gland with loss of homogeneous echogenicity and hypoechoic areas
Click here to view |
When the other USG results are evaluated, soft-tissue abscesses in 10.8% of USG patients, nasolabial cyst [Figure 4] in 4.5%, masseter hypertrophy [Figure 5] in 2.7%, palatal masses in 2.7%, and 6.3% of other lesions were evaluated. Intraoral USG was used in all mucosal lesions and palatal masses. No pathology was found in 11.7% of the patients examined, and most of them were salivary gland examination. | Figure 5: Masseter muscle examination and measurement of thickness by ultrasonography
Click here to view |
| Discussion | | |
In parallel to the rapid advancement of technology, there are new developments in radiology day by day, devices are developed and even new techniques emerge. In this respect, both dental radiology and maxillofacial imaging should capture the latest technological developments. In addition to conventional radiography techniques, advanced imaging methods such as CT, MRI, and USG are increasingly used in dental radiology today. Although USG is not a very new technique, it does not attract enough attention in the field of dental radiology. So much so that the use of USG in dental radiology came to the fore in 1963.[2] Perhaps, the perception that only soft tissues can be examined with USG may have a role in this. In addition, USG images have always been complex for dental radiologists and they did not dare to interpret them. USG creates a perception like Pandora's Box in many dental radiologists. In addition, most dentists and some of the dental radiologists are unfortunately not aware of the contributions USG will provide them. For example, in the dental radiology clinic where the present study was conducted, the number of CBCT scanning performed in the last 5 years was approximately 5000, while the number of USGs performed and reported was only 111. There is no study similar to the present study in the literature, namely existing articles were either reviews or case reports on the use of USG in dentistry.[4],[16],[17] There was no study in which all USG reports applied in a clinic were compiled. In this respect, this study will be the first.
In the present study, it was found that USG was most commonly used to examine lymph nodes (29%). There are approximately 800 lymph nodes in the human body, and 300 of them are located above the neck.[18] Since the neck is a drainage area, lymphadenopathy in this area is very important to evaluate. Lymph nodes can be evaluated radiologically with CT, MRI, and USG. CT use is particularly limited in pregnant patients and children due to the risk of ionizing radiation. Although MRI has sufficient soft-tissue resolution, it has disadvantages such as not being available at every center, not being able to distinguish malignant and benign lymph nodes and inadequate differentiation of calcific lymph nodes.[10] In this sense, USG is a noninvasive, easy, simultaneous method that is frequently used in lymph node examinations. USG also provides more sensitive and more accurate values than palpation in the evaluation of cervical lymph nodes. The shape, border, echogenicity, hilus, blood supply, calcification, and necrosis of the lymph node can be evaluated by USG. In this study, supramandibular lymph nodes which are facial lymph nodes were the most evaluated lymph nodes by USG (14.4% of all patients), and followed by the supmandibular lymph nodes (10.8% of all patients). In a recent study, Caglayan et al.[19] found the frequency of facial supramandibular lymph nodes to be 17% among dental patients. Facial nodes are mobile structures that lie within the soft tissues of the cheek between the skin and the buccinator muscle at the anterior border of the masseter muscle and they provide drainage of soft tissues such as skin and mucous membranes. They also play an important role in the spread and diagnosis of facial malignancies. Since dentists usually focus on the submandibular lymph nodes that drain the teeth, they may be inadequate in the examination of facial lymph nodes. In this regard, USG is a very useful technique that can contribute to diagnosis and treatment.
In the present study, another common use of USG was salivary gland examinations (16.2%) after lymph node examinations and mucosal lesions. In the imaging of the salivary glands, it is recommended that CT with or without contrast, MRI with or without contrast, sialography and MRI sialography, and USG should be applied depending on the clinical data.[14] According to Yousem et al.,[20] USG replaces CT and MRI in imaging of superficial salivary gland lesions. When combined with clinical findings, USG allows the physician to rapidly examine normal and pathological salivary glands. Normal salivary glands must show homogeneous echogenous parenchymal structure in USG. Sialolithiasis was the most common salivary gland disease and occurs most often in the submandibular gland and it was most often salivary gland pathology in the present study also. Although calcific stones can be imaged with conventional radiography techniques and CBCT, the relationship of these structures with soft tissues can only be clearly determined by USG. Since it has been stated that not all calcifications detected in the submandibular area are salivary stones, and some of them may be lymph node calcification.[21] The relationship of the stone with the gland parenchyma or its ducts can be clearly determined by USG. Wharton canal can be well examined and small-sized stones can also be detected with intraoral USG also. In this study, all salivary gland examinations were performed extraorally, except for one sublingual gland stone which was detected by intraoral USG.
In addition, the ability to examine blood flow and vascularization thanks to Doppler ultrasound contributes to differentiating solid and cystic lesions. In our study, solid lesions of salivary glands were found in 3.6% of the patients and sialadenitis in 1.8% of patients. USG provides valuable information in inflammatory diseases of the salivary gland. Thus, in acute cases, the glands are enlarged and appear more hypoechoic with an increase in blood flow, whereas in chronic cases, loss of homogeneous echogenicity of the gland and hypoechoic areas is observed.[14] USG may sometimes have some limitations in imaging the salivary glands, that is, it is difficult to view the inframandibular part, which is the deep lobe of the parotid gland and the deep lobes of the submandibular gland with USG.[22] In such cases, it may be appropriate to use MRI or CT together with USG, depending on the case.
Mucosal lesions were examined in 18.9% of the patients in the present study and the majority of them consisted of oral hemangiomas and all of them were examined by intraoral USG. Areas that the hockey stick probe can easily reach, such as tongue, lips, and buccal mucosa are suitable for intraoral USG examination. Several studies have reported that USG is useful in evaluating the thickness of some primary lesions in oral mucosa.[23] Wakasugi-Sato et al.[24] also demonstrated the clinical applications of USG in imaging of soft-tissue lesions, guided fine-needle aspiration, measurement of tongue cancer thickness, and diagnosis of metastasis to cervical lymph nodes. USG is a noninvasive rapid technique that makes a clear contribution to the diagnosis by clearly showing the blood supply and borders of the lesion.
In our study, abscesses were examined in 10.8% of USG patients. Abscess pouches are observed as heterogeneous areas with unclear borders with posterior acoustic enhancement on USG. Central liquefaction and debris may be seen as avascular areas and abscess gases seen as hyperechogenic areas.[14] It was stated that the diagnostic accuracy of USG in the diagnosis of space infections and abscesses was 90% and 100% in lymphadenopathies.[4] A clear examination of abscesses with USG actually may allow abscess drainage with USG also.
Another area in which USG was used in the diagnosis of our study was nasolabial cysts (4.5%). As it is known, nasolabial cyst is a soft-tissue lesion and therefore does not show any finding in radiography or CBCT. However, it can be seen with MRI or USG. Like other cystic lesions, this is seen as regularly demarcated hypoechoic lesions with posterior acoustic enhancement on USG, not showing central blood supply in the Doppler. There are few cases of nasolabial cyst diagnosed by USG in the literature.[25] Another area in which USG was used in our study was masseter muscle examination (2.7%). Thickness, internal structure, blood supply, and even spasm points of masseter muscles can be examined in a short time with USG.[11] Furthermore, palatal masses were examined in 2.7% of our patients. When examining the palatal masses by USG, well-delimited margins of the palatal tumors are related to the presence of a histological capsule, and posterior echo enhancement shows defects in the palatal bone.[26] They are usually related to minor salivary glands and they are more likely to be malignant.
Despite such advantages of USG, its use in dental radiology is limited and the most commonly used area was the evaluation of lymphadenopathy, salivary glands, and mucosal lesions in accordance with general information. However, many advantages of USG are known in the diagnosis and treatment of soft-tissue lesions and even some pathologies of hard tissues.[27] As in every field, new developments are occurring day by day in USG also. Techniques such as elastography, microvascular imaging, and contrast-enhanced USG are now in use.[28],[29] The fact that CBCT is the most popular advanced imaging technique in dental radiology clinics is of course natural due to its advantages such as high spatial resolution in hard tissues, ability to obtain real-size images in desired planes, and X-ray dose compared to medical CT.[30] In this respect, the superiority of CBCT in dental radiology is indisputable. However, the most important handicaps of CBCT are the risk of ionizing radiation and lack of soft-tissue resolution. In this case, USG should not be avoided in pathologies involving soft tissue, which may be combined with CBCT in appropriate cases.
| Conclusion | | |
Dental radiologists should not refrain from USG in soft-tissue pathologies and they should perform USG examinations more boldly. Since USG has no known risks. Therefore, they can apply repeatedly and obtain ideal images and after improving themselves on normal anatomy, they can easily begin to distinguish pathologies. Apart from the known classical usage areas of USG, they should know that it can also be used in TMJ disorders, orthodontic applications, implant applications, jawbone lesions, periodontal examinations, interventional anesthetic or muscular injections, and many more. Hence, they should follow the developments in this field continuously. They should be aware of the benefits that USG will provide them and therefore their patients.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]
[Table 1]
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