|Year : 2015 | Volume
| Issue : 1 | Page : 20-24
Comparison of ultrasound, digital, and conventional radiography in differentiating periapical lesions: An in vivo study
Purnachandrarao Naik Nunsavathu1, Ravi Kiran Alaparthi1, Samatha Yelamanchili1, Neha Vashisht2, Ravindra Naik Gugulothu3, Sri Krishna Koppula4
1 Department of Oral Medicine and Radiology, Sibar Institute of Dental Sciences, Guntur, Andhra Pradesh, India
2 Private Practitioner, Shimla, Himachal Pradesh, India
3 Department of Oral Medicine and Radiology, Mamatha Dental College and Hospital, Khammam, Telangana, India
4 Department of Oral Medicine and Radiology, Hazaribag College of Dental Sciences, Hazaribag, Jharkhand, India
|Date of Submission||08-Aug-2014|
|Date of Acceptance||13-Jul-2015|
|Date of Web Publication||12-Oct-2015|
Purnachandrarao Naik Nunsavathu
Department of Oral Medicine and Radiology, Sibar Institute of Dental Sciences, Guntur, Andhra Pradesh
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Aims and Objectives: To evaluate in vivo the efficacy of ultrasound, digital and conventional radiography in identifying periapical lesions. To compare the results of the above imaging modalities with histopathology, which is considered to be the gold standard for diagnosis. Materials and Methods: Thirty patients aged between 15 and 45 years with periapical lesions associated with maxillary or mandibular anterior teeth indicated for endodontic surgery or extraction were selected for the study. Pre-operatively, conventional, digital periapical radiography and ultrasonography were done and interpreted. Endodontic surgery or extraction was performed including curettage of apical tissue to enable histopathological investigation, which provided the gold standard diagnosis. All measurements and findings were compared and statistically analyzed. Results: In conventional and digital radiography, the periapical lesions were readily identified but observers were unable to differentiate granuloma from cyst using these modalities only. But ultrasonography was able to give the true nature of the periapical pathology. All the cases diagnosed by ultrasound were confirmed with histopathology, and maximal number of cases diagnosed by ultrasound correlated with the histopathological diagnosis. Conclusion: The present study confirms that ultrasound is a promising and reliable imaging technique for differentiating periapical lesions i.e., periapical cysts and granulomas. Based on the echo texture of their contents and the presence of vascularity using color Doppler, periapical cyst and granulomas can be readily identified. The present study is further applicable for the evaluation of periapical lesions of the posterior teeth and evaluation of other jaw lesions.
Keywords: Conventional and digital radiography, periapical cyst, periapical granuloma ultrasound
|How to cite this article:|
Nunsavathu PN, Alaparthi RK, Yelamanchili S, Vashisht N, Gugulothu RN, Koppula SK. Comparison of ultrasound, digital, and conventional radiography in differentiating periapical lesions: An in vivo study. J Indian Acad Oral Med Radiol 2015;27:20-4
|How to cite this URL:|
Nunsavathu PN, Alaparthi RK, Yelamanchili S, Vashisht N, Gugulothu RN, Koppula SK. Comparison of ultrasound, digital, and conventional radiography in differentiating periapical lesions: An in vivo study. J Indian Acad Oral Med Radiol [serial online] 2015 [cited 2019 Dec 14];27:20-4. Available from: http://www.jiaomr.in/text.asp?2015/27/1/20/167069
| Introduction|| |
Endodontics has traditionally relied heavily on radiography. Pre-operatively, intra-operatively and post-operatively the endodontic patient is often exposed to radiation of a single site repeatedly in spite of which the nature of the underlying disease is notoriously difficult to determine from radiographs alone.  Correct diagnosis of a periapical lesion aids in predicting the treatment outcome and helps in decreasing the incidence of root canal treatment failure associated with lack of proper diagnosis owing to the limitations of routinely used conventional and digital radiography. 
Thus research into alternative, non-invasive imaging techniques is necessary to see if they can provide the endodontist with more information, while at the same time reducing radiation exposure.  One such modality being used in this field is ultrasonography. The number of studies investigating the role of ultrasound in the diagnosis of bone lesions of the jaw is limited. Lauria et al. first evaluated the role of ultrasound as a complementary examination in the diagnosis of intra-osseous lesions of the jaws. In 2002 and 2003 Cotti et al. and in 2006 Gundappa et al. reported positive findings using ultrasound in the differential diagnosis of periapical lesions.  This study was aimed to compare ultrasound, digital, and conventional radiography in differentiating periapical lesions.
| Materials and Methods|| |
This study comprised 30 patients aged between 15 and 45 years with periapical lesions associated with maxillary or mandibular anterior teeth indicated for endodontic surgery or extraction. Patients with endo-perio lesions, root canal-treated teeth and with any underlying systemic illness were excluded from the study. Approval from the ethical committee was obtained, and informed consent was taken from each patient after explaining the aim and methodology of the study. Patients were subjected first to conventional intraoral periapical radiographs, then digital radiographs, followed by ultrasound imaging.
Equipment used for conventional radiography were film holder with beam aiming device (Autoclavable Rinn XCP-ORA), X-mind tm x-ray system (70 kv, 8 mA, 0.425 KVA, 2-mm aluminium filter, effective beam at cone tip 60 mm, 31 cm SSD) manufactured by Satelec (India) Private Limited, E-speed film (No: 2, 31 × 41 mm), view box and vernier caliper with millimeter scale. Digital radiographs were taken by using paralleling technique using SuniRay digital charged coupled device (CCD), model no CCD 0503302YB, intraoral sensor size: 2 (39 × 23 mm), and SuniRay Software with computer monitor. The ultrasonographic equipment consisted of color Doppler ultrasound scan machine, model "MY LAB-40" of ESOATA Biomedica Company Limited. A linear array transducer manufactured by "MY LAB-40" of ESOATA Biomedica company limited, which is a multi frequency probe (7.5 MHZ), was used for all the scans in this study. To take prints a high quality printing paper UP-895 MD manufactured by Sony Corporation, Tokyo, Japan was used.
Preoperative periapical radiographs were taken for all the patients using paralleling technique and the diagnosis was given based on the criteria suggested by Wood and Goaz.
- Periapical granuloma as a well-circumscribed periapical radiolucency measuring <1.6 cm in diameter. 
- Periapical cyst as a well-defined periapical radiolucency with sclerotic border measuring >1.6 cm in diameter. 
- Periapical abscess as an ill-defined periapical radiolucency with diffuse margins. 
The dimensions of all the lesions were measured in mesiodistal (MD) and superoinferior (SI) directions by using a caliper on a millimeter scale. After conventional radiographic examination, the patients were subjected to digital radiographic examination and the SI and MD dimensions of the periapical lesion were measured by using the digital ruler to minimize the bias. And the diagnosis was made based on the criteria similar to conventional radiography. After radiographic examination, patients were taken for sonographic examination and after ultrasound examination, a tentative diagnosis was agreed upon, based on the following criteria by an expert ultrasonographer.
A hypo-echoic well-contoured cavity surrounded by a reinforced bone walls, filled with fluid and with no evidence of internal vascularization on color Doppler examination.
A poorly defined hypo-echoic area, showing rich vascular supply on color Doppler examination.
Predominantly hypo-echoic area with focal anechoic area, showing vascularity in some areas on color Doppler examination.
All intraoral conventional and digital radiographs were analyzed by two experts: a radiologist and an endodontist and diagnoses were given separately. All the ultrasound images were also interpreted and diagnosis given by expert ultrasonographer. Once the measurements were taken and diagnosed, the patients were subjected to extraction or endodontic therapy followed by periapical curettage for biopsy, which is considered to be the gold standard for diagnosis.
| Results|| |
All the cases diagnosed by ultrasound were confirmed with histopathology. Among 30 cases, four cases were diagnosed histopathologically as periapical granulomas and 26 cases as periapical cyst. Twenty-six cases diagnosed by ultrasound as periapical cysts were confirmed by histopathology [Figure 1], [Figure 2], [Figure 3] and [Figure 4]. Three cases diagnosed as periapical cyst by ultrasonography, were not correlating histopathologically. They showed the characteristic of a periapical granuloma. One case was diagnosed as periapical granuloma by ultrasound, and was confirmed histopathologically as granuloma. The percentage accuracy of diagnosis in conventional radiography by observer 1 and observer 2 was 93.33%; similarly, for the digital radiograph, percentage accuracy was 100%. The inter-examiner agreement for ultrasound and histopathology was 90% with P < 0.010 which was considered significant [Graph 1 [Additional file 1] ] and [Table 1].
|Figure 1: Conventional radiographic images showing well-circumscribed periapical radiolucency in relation to 21 and 22 measuring <1.6 cms suggestive of periapical granuloma|
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|Figure 2: Digital radiographic images showing well-circumscribed periapical radiolucency in relation to 21 and 22 measuring <1.6 cms suggestive of periapical granuloma|
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|Figure 3: Ultrasound images revealed hypoechoic area without any vascularity on color Doppler examination suggestive of 'periapical cyst'|
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|Figure 4: Histopathological examination showed acellular, eosinophilic structures within the squamous lining of periapical cyst|
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| Discussion|| |
In routine dental practice, radiographs act as a back bone in diagnosing periapical lesions and helps in treatment planning, monitoring details during endodontic treatment and follow-up of treatment outcomes.  The possibility of diagnosing a periapical lesion, accurately measuring it, describing its histopathological features and understanding the severity of the infection may help understand its healing potential. It is also important in assessing treatment results and for epidemiological studies.  Several radiographic features such as size and shape of the lesion and the presence of sclerotic border demarcating the lesion support the diagnosis of periapical lesions. Radiographically periapical granuloma is a well-circumscribed periapical radiolucency measuring <1.6 cm in diameter. Periapical cyst is a well-defined periapical radiolucency with sclerotic border measuring >1.6 cm in diameter. , Mecall and Wald proposed that periapical cyst could be differentiated radiographically from granulomas on the basis of their larger size (9.5 mm in diameter), and the presence of a radiopaque cortex. , Periapical lesions cannot be differentiated into cystic and non-cystic based on radiographic features alone, because of lots of variations in literature regarding size. In a recent histopathological study of periapical lesion, it was conclusively shown that no relation existed between the presence of radiopaque border and the histopathologic diagnosis of a cyst. ,
The conventional root canal therapy is the main treatment modality for periapical granuloma but has limited value for periapical cysts; periapical cysts, particularly smaller ones, heal completely after root canal therapy, whereas larger cysts are less likely to resolve by non-surgical endodontics and therefore, may affect the treatment outcome. , Ultrasound real-time imaging is a more convenient diagnostic aid than other modalities because it is easy, reproducible and convenient to use. , The equipment is relatively cheap when compared with the other advanced imaging modalities. Images obtained are easy to read once the observer is trained. It prevents unnecessary exposure of the patient to ionizing radiation and no harmful effects of ultrasound waves have been observed in the tissue as a result of ultrasound examination.
In the present study, the level of agreement between the two observers with respect to diagnosis carried out using conventional and digital radiography was highly significant. As per the studies conducted by Gundappa et al. (2006), using analysis of variance (ANOVA), there was no significant difference between three observers, nor on the three conclusions when using conventional radiography.  In a study by Raghav et al. (2010) the interobserver reliability for measuring the dimensions of periapical lesions was analyzed by using ANOVA for CR and DR, and P-value of <0.05 was accepted as statistically significant.  In our study, the percentage accuracy of conventional and digital radiography by both observer 1 and observer 2 was 93.33% and 100%, respectively, which indicates the percentage accuracy for digital radiography was more compared to conventional radiography. Our study supports the findings of Tirrell et al., who found that the digital radiographic images revealed the lesions earlier than conventional radiography.  Also this observation is similar to observations made by Raghav et al. (2010),  where the percentage accuracy of digital radiography was more than conventional radiography. In one study, analysis revealed that the digital images were inferior (P < 0.01) to conventional radiography in visualizing bone lesions regardless of whether the lesion was large or small.
In the present study, the diagnosis carried out using ultrasound was compared with histopathology using Chi-square tests, which was statistically significant. Out of 30 cases, 27 cases diagnosed by ultrasound were confirmed with histopathology. These findings are consistent with the findings made by Cotti et al. in 2002 and 2003, who reported positive findings using ultrasound in the differential diagnosis of periapical lesions.  Only one case diagnosed as periapical granuloma by ultrasound, was confirmed as periapical granuloma. Out of 30 cases, 29 cases were diagnosed as periapical cyst by ultrasound, from which three cases were diagnosed as periapical granuloma and 26 cases were diagnosed as periapical cyst by histopathology. This observation is similar to the observations made by Cotti et al. (2002 and 2003)  and Gundappa et al. (2006)  where they have accurately diagnosed all the periapical granulomas ultrasonographically.
In our study measurements made with conventional radiograph and digital radiograph, were compared with the ultrasound measurement and were almost always smaller than the corresponding radiographic measurement with a mean SI measurement of 9.16 mm and mean MD measurement of 10.70 mm. This could be attributed to the fact that the bony edges of the lesions cast an acoustic shadow on the lateral walls, making it difficult to place the electronic caliper for exact measurement. This observation is similar to the observation made by Raghav et al. (2010). By obtaining real time imaging using ultrasound, a working diagnosis could be made without delay and may prevent unnecessary exposure of the patient to ionizing radiation, and no harmful effects of ultrasound waves have been observed in the tissues as a result of ultrasound examination. ,
| Conclusion|| |
The present study has confirmed that ultrasound imaging provides sufficient information with regard to the nature of the periapical lesions, unlike conventional and digital radiography and is a reliable diagnostic technique for differentiating periapical lesions, i.e., periapical cyst and periapical granulomas based on their contents and presence of vascularity using color Doppler. Hence, ultrasound imaging has a potential to be used as an adjunct to routine use of conventional and digital radiography in the diagnosis of periapical pathology and is further applicable for the evaluation of periapical lesions of the posterior teeth and evaluation of other jaw lesions. The result of this study should be further confirmed using a larger sample size.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]