T2 relaxation mapping MRI of healthy and inflamed gingival tissue

Periapical bone edema volume in 3D MRI is positively correlated with bone architecture changes

OBJECTIVES

To compare and correlate bone edema volume detected by 3D-short-tau-inversion-recovery (STIR) sequence to osseous decay detected by a T1-based sequence and conventional panoramic radiography (OPT).

MATERIALS AND METHODS

Patients with clinical evidence of apical periodontitis were included retrospectively and received OPT as well as MRI of the viscerocranium including a 3D-STIR and a 3D-T1 gradient echo sequence. Bone edema was visualized using the 3D-STIR sequence and periapical hard tissue changes were evaluated using the 3D-T1 sequence. Lesions were segmented and volumes were calculated for bone edema and structural decay. OPTs were assessed for corresponding periapical radiolucencies using the periapical index (PAI).

RESULTS

Of the 42 patients of the initial cohort 21 patients with 38 periapical lesions were included in the analysis (mean age 57.2 ± 13.8 years, 9 women). Reactive bone edema was detected on MRI in 23 periapical lesions with corresponding radiolucency on OPT. Fifteen periapical lesions were detected only in the STIR sequence. The volume of edema measured in the STIR was significantly larger in OPT-positive lesions (mean: STIR (OPT+) 207.3 ± 191.1 mm³) compared to OPT-negative lesions (mean: STIR (OPT-) 29.5 ± 34.2 mm³, p < 0.001). The ROC curve analysis demonstrated that Volume T1 (0.905, p < 0.01) and Volume STIR (0.857, p < 0.01) measurements have strong diagnostic performance for distinguishing OPT-positive from OPT-negative lesions.

CONCLUSION

Clinically symptom-free patients without pathologic changes in OPT can show signs of inflammation within the periapical bone. Bone edema volume visualized by STIR sequence exceeds bone architecture changes indicated in T1-based imaging and might precede osteolysis in dental radiography.

CRITICAL RELEVANCE STATEMENT

These results show that subtle intraosseous inflammation within the periapical tissue might remain undetected by conventional dental radiography and T1-based sequences. This emphasizes the potential of MRI in secondary prevention in dentistry.

KEY POINTS

Conventional panoramic radiography (OPT) may show only delayed findings of pathological periapical changes. MRI detected bone edema in 23 radiolucent lesions on OPT. MRI revealed 15 lesions only visible with STIR sequences. STIR sequences showed bone inflammation undetectable by conventional radiography or T1 imaging. MRI offers diagnostic advantages for early dental pathology detection.

Detection of caries lesions using a water-sensitive STIR sequence in dental MRI

In clinical practice, diagnosis of suspected carious lesions is verified by using conventional dental radiography (DR), including panoramic radiography (OPT), bitewing imaging, and dental X-ray. The aim of this study was to evaluate the use of magnetic resonance imaging (MRI) for caries visualization. Fourteen patients with clinically suspected carious lesions, verified by standardized dental examination including DR and OPT, were imaged with 3D isotropic T2-weighted STIR (short tau inversion recovery) and T1 FFE Black bone sequences. Intensities of dental caries, hard tissue and pulp were measured and calculated as aSNR (apparent signal to noise ratio) and aHTMCNR (apparent hard tissue to muscle contrast to noise ratio) in both sequences. Imaging findings were then correlated to clinical examination results. In STIR as well as in T1 FFE black bone images, aSNR and aHTMCNR was significantly higher in carious lesions than in healthy hard tissue (p < 0.001). Using water-sensitive STIR sequence allowed for detecting significantly lower aSNR and aHTMCNR in carious teeth compared to healthy teeth (p = 0.01). The use of MRI for the detection of caries is a promising imaging technique that may complement clinical exams and traditional imaging.

Evaluation of 3D MRI for early detection of bone edema associated with apical periodontitis

OBJECTIVES

To detect and evaluate early signs of apical periodontitis using MRI based on a 3D short-tau-inversion-recovery (STIR) sequence compared to conventional panoramic radiography (OPT) and periapical radiographs in patients with apical periodontitis.

MATERIALS AND METHODS

Patients with clinical evidence of periodontal disease were enrolled prospectively and received OPT as well as MRI of the viscerocranium including a 3D-STIR sequence. The MRI sequences were assessed for the occurrence and extent of bone changes associated with apical periodontitis including bone edema, periradicular cysts, and dental granulomas. OPTs and intraoral periapical radiographs, if available, were assessed for corresponding periapical radiolucencies using the periapical index (PAI).

RESULTS

In total, 232 teeth of 37 patients (mean age 62±13.9 years, 18 women) were assessed. In 69 cases reactive bone edema was detected on MRI with corresponding radiolucency according to OPT. In 105 cases edema was detected without corresponding radiolucency on OPT. The overall extent of edema measured on MRI was significantly larger compared to the radiolucency on OPT (mean: STIR 2.4±1.4 mm, dental radiograph 1.3±1.2 mm, OPT 0.8±1.1 mm, P=0.01). The overall PAI score was significantly higher on MRI compared to OPT (mean PAI: STIR 1.9±0.7, dental radiograph 1.3±0.5, OPT 1.2±0.7, P=0.02).

CONCLUSION

Early detection and assessment of bone changes of apical periodontitis using MRI was feasible while the extent of bone edema measured on MRI exceeded the radiolucencies measured on OPT.

CLINICAL RELEVANCE

In clinical routine, dental MRI might be useful for early detection and assessment of apical periodontitis before irreversible bone loss is detected on conventional panoramic and intraoral periapical radiographs.

Visualization of clinically silent, odontogenic maxillary sinus mucositis originating from periapical inflammation using MRI: a feasibility study

OBJECTIVES

Maxillary sinus mucositis is frequently associated with odontogenic foci. Periapical inflammation of maxillary molars and premolars cannot be visualized directly using radiation-based imaging. The purpose of this study was to answer the following clinical question: among patients with periapical inflammatory processes in the maxilla, does the use of magnetic resonance imaging (MRI), as compared to conventional periapical (AP) and panoramic radiography (OPT), improve diagnostic accuracy?

METHODS

Forty-two subjects with generalized periodontitis were scanned on a 3 T MRI. Sixteen asymptomatic subjects with mucosal swelling of the maxillary sinus were enrolled in the study. Periapical edema was assessed using short tau inversion recovery (STIR) sequence. Apical osteolysis and mucosal swelling were assessed by MRI, AP, and OPT imaging using the periapical index score (PAI). Comparisons between groups were performed with chi-squared tests with Yates' correction. Significance was set at p < 0.05.

RESULTS

Periapical lesions of maxillary premolars and molars were identified in 16 subjects, 21 sinuses, and 58 teeth. Bone edema and PAI scores were significantly higher using MRI as compared to OPT and AP (p < 0.05). Using the STIR sequence, a significant association of PAI score > 1 and the presence of mucosal swelling in the maxillary sinus was detected (p = 0.03).

CONCLUSION

Periapical inflammation and maxillary mucositis could be visualized using STIR imaging. The use of MRI may help detect early, subtle inflammatory changes in the periapical tissues surrounding maxillary dentition. Early detection could guide diagnostic criteria, as well as treatment and prevention.

Magnetic resonance imaging as a diagnostic tool for periodontal disease: A prospective study with correlation to standard clinical findings-Is there added value?

AIM

To evaluate the correlation between standard clinical findings, radiographic (OPT) and magnetic resonance imaging (MRI) as well as to assess whether MRI is capable of providing additional information related to the severity and extent of periodontal disease.

METHODS

42 patients with generalized periodontitis received pre-interventional MRI scans. These were compared to MR images of a periodontal healthy control group (n = 34). The extent of the osseous oedema, detected by MRI, was set in correlation with clinical periodontitis-associated findings.

RESULTS

A highly significant correlation between bone oedema and clinical testings such as probing depth (p < 0.0001) and bleeding on probing (p < 0.0001) was revealed. The oedema exceeded the extent of demineralized bone. Patients with a positive BOP test showed a 2.51-fold increase in risk of already having a bone oedema around the respective tooth even if probing depth was ≤3 mm (logistic binary regression analysis, OR 2.51; 95% CI: 1.54-4.11; p < 0.0001).

CONCLUSION

MRI findings correlated with standard clinical findings, and MRI was able to depict intraosseous changes before any osseous defect had occurred.