Acurácia da ressonância magnética de crânio como exame de imagem para o diagnóstico de periodontite apical crônica : resultados preliminares de um estudo de validação diagnóstica

Abstract

Chronic apical periodontitis (CAP) is an inflammatory lesion of the periapical tissues, usually asymptomatic, that occurs in response to the presence of root canal system infection. The CAP leads to periapical bone resorption, and its diagnosis is made through the conjunction of clinical data and imaging exams. The most frequently used exams for CAP diagnosis are: periapical radiography, panoramic radiography and / or localized computed tomography cone beam. Invariably, these tests expose the patient to different doses of ionizing radiation. Magnetic Resonance (MRI) is an exam that evaluates different types of tissue and is widely used in several areas of medicine and dentistry. In addition to being a non-invasive, high-resolution method, MRI allows the differentiation of liquid and solid components of a region or tissue. The objective of this study was to investigate the use of MRI of the brain as an imaging method of the CAP, evaluating its accuracy compared to tomographic examinations, considered as the standard test. Nineteen hospitalized patients with MRI exams and multidetector computed tomography (MDCTA) were selected according to inclusion criteria, making a total of 346 teeth analyzed. The CAP diagnosis was recorded separately, through the MRI and the MDCTA, by two examiners: an endodontist (E1) and a dental radiologist (E2). The main exposure validity (MRI) was calculated based on CAP diagnosis through the MDCTA, classified as present or absent CAP. Values of accuracy, sensitivity, specificity, positive and negative predictive values (PPV and NPV), efficiency and positive and negative likelihood ratio (PLR and NLR) were calculated for each examiner. The mean age of participants was 62.10 ± 14.27 years, with 52.62% of males. The prevalence of CAP in MRI and MDCTA was: (E1 = 5.3%, E2 = 15.79%) and (E1 = 37.5%, E2 = 47.4%), considering the patients as a unit of analysis. The validity values of the CMR for the diagnosis of PAC were: accuracy (E1 = 0.962; E2 = 0.959); sensitivity (E1 = 0.187, E2 = 0.263); specificity (E1 = 1.00, E2 = 1.00); PPV (E1 = 1.00, E2 = 1.00) and NPV (E1 = 0.962, E2 = 0.958); efficiency (E1 = 0.593, E2 = 0.631); and NLR (E1 = 0.813, E2 = 0.737). The PLR could not be calculated since the specificity value was 1. Preliminary results suggest that MRI has the potential to be used as an imaging method for the diagnosis of CAP, with no side effects related to ionizing irradiation and with high values of accuracy, specificity, PPV and NPV. However, the sensitivity of MRI was very low, that is, there were many false-negative diagnoses (dental elements that were healthy in the MRI and presented CAP in the MDCTA). In addition, the proportion of true-positive diagnoses among the teeth diagnosed with CAP through the MDCTA was small. Future studies should investigate MRI acquisition protocols that are specific for visualizing oral structures in order to improve MRI efficiency for CAP diagnosis.