Ultrashort echo time (UTE) MRI for the assessment of caries lesions

Bracher, A-K; Hofmann, Christian; Bornstedt, Axel; Hell, Erich; Janke, F; Ulrici, J.; Haller, Bernd; Geibel, Margrit-Ann; Rasche, Volker

doi:10.1259/dmfr.20120321

Cited by 55 publications

(35 citation statements)

References 39 publications

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“…UTE is a relatively novel method that allows for the visualization of solid structures 17 and has been also described as useful in the field of dentistry. 2,18 Because of its very short TE and use of high bandwidth, it is expected that UTE scans will yield the smallest artefact areas. One limitation of our study, however, is the very restricted choice and range of editable parameters in the pre-commercial UTE pulse sequence provided by the scanner manufacturer, preventing statistical comparisons with general GRE and SE results.…”

Section: Discussionmentioning

confidence: 99%

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Influence of pulse sequence parameters at 1.5 T and 3.0 T on MRI artefacts produced by metal–ceramic restorations

Cortes

Abdala-Júnior

Weber

et al. 2015

Dentomaxillofacial Radiology

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Objectives: Susceptibility artefacts from dental materials may compromise MRI diagnosis. However, little is known regarding MRI artefacts of dental material samples with the clinical shapes used in dentistry. The present phantom study aims to clarify how pulse sequences and sequence parameters affect MRI artefacts caused by metal-ceramic restorations. Methods: A phantom consisting of nickel-chromium metal-ceramic restorations (i.e. dental crowns and fixed bridges) and cylindrical reference specimens immersed in agar gel was imaged in 1.5 and 3.0 T MRI scanners. Gradient echo (GRE), spin echo (SE) and ultrashort echo time (UTE) pulse sequences were used. The artefact area in each image was automatically calculated from the pixel values within a region of interest. Mean values for similar pulse sequences differing in one parameter at a time were compared. A comparison between mean artefact area at 1.5 and 3.0 T, and from GRE and SE was also carried out. In addition, a parametric correlation between echo time (TE) and artefact area was performed. Results: A significant correlation was found between TE and artefact area in GRE images. Higher receiver bandwidth significantly reduced artefact area in SE images. UTE images yielded the smallest artefact area at 1.5 T. In addition, a significant difference in mean artefact area was found between images at 1.5 and 3.0 T field strengths (p 5 0.028) and between images from GRE and SE pulse sequences (p 5 0.005). Conclusions: It is possible to compensate the effect of higher field strength on MRI artefacts by setting optimized pulse sequences for scanning patients with metal-ceramic restorations.

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Section: Discussionmentioning

confidence: 99%

“…[1][2][3][4] MRI provides multiplanar imaging with satisfactory soft-tissue contrast using non-ionizing electromagnetic fields. However, MRI is prone to artefacts caused by the presence of metallic materials, namely susceptibility artefacts, which may preclude a clinical diagnosis or lead to an erroneous diagnosis.…”

Section: Introductionmentioning

confidence: 99%

Influence of pulse sequence parameters at 1.5 T and 3.0 T on MRI artefacts produced by metal–ceramic restorations

Cortes

Abdala-Júnior

Weber

et al. 2015

Dentomaxillofacial Radiology

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“…It has been shown [5,6] that at least 30 % mineral loss is required to detect a bony lesion on XR-based imaging methods. Instead, MRI can show the signal changes before substantial mineral loss occurs, due to its sensitivity to the changes in the number of water molecules in a given lesion [43,44]. From the clinical routine it is well known that the lesion extent is often underestimated by XR-based methods, indicating only a limited performance in definition of the accurate lesion border.…”

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confidence: 99%

Assessment of Apical Periodontitis by MRI: A Feasibility Study

Geibel

Schreiber

Bracher

et al. 2015

Fortschr Röntgenstr

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Purpose: The purpose of this clinical feasibility study was to evaluate the applicability of magnetic resonance imaging (MRI) for the assessment of apical periodontitis in direct comparison with cone beam CT (CBCT). Materials and Methods: 19 consecutive patients (average age 43???13 years) with 34 lesions in total (13 molars, 14 premolars and 7 front teeth) were enrolled in this feasibility study. Periapical lesions were defined as periapical radiolucencies (CBCT) or structural changes in the spongy bone signal (MRI), which were connected with the apical part of a root and with at least twice the width of the periodontal ligament space. The location and dimension of the lesions were compared between MRI and CBCT. Results: While mainly mineralized tissue components such as teeth and bone were visible with CBCT, complimentary information of the soft tissue components was assessable with MRI. The MRI images provided sufficient diagnostic detail for the assessment of the main structures of interest. Heterogeneous contrast was observed within the lesion, with often a clear enhancement close to the apical foramen and the periodontal gap.?No difference for lesion visibility was observed between MRI and CBCT. The lesion dimensions corresponded well, but were slightly but significantly overestimated with MRI. A heterogeneous lesion appearance was observed in several patients. Four patients presented with a well circumscribed hyperintense signal in the vicinity of the apical foramen. Conclusion: The MRI capability of soft tissue characterization may facilitate detailed analysis of periapical lesions. This clinical study confirms the applicability of multi-contrast MRI for the identification of periapical lesions. Key Points: ??MRI can be applied for the identification of periapical lesions without ionizing radiation exposure ??MRI might facilitate more detailed characterization of periapical lesions ??MRI might provide more accurate lesion dimensions as X-ray-based methods Citation Format: ??Geibel MA., Schreiber ES, Bracher AK et?al. Assessment of Apical Periodontitis by MRI: A Feasibility Study. Fortschr R?ntgenstr 2015; 187: 269???275

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“…A three‐dimensional UTE sequence was used to investigate the MR relaxation properties and a ZTE sequence was employed for imaging of the CPC‐restored teeth. Although both sequences are able to detect tissues with very short transverse relaxation times at high SNR, their respective intrinsic features make them suitable for different purposes . The selection of TE values in UTE enables images with T 2 * contrast to be acquired and also for signals from materials with extremely fast decay, such as components of the radiofrequency (RF) coil, to be suppressed.…”

Section: Methodsmentioning

confidence: 99%

“…These sequences have been applied in bone imaging for qualitative and quantitative analysis of cortical bone and direct depiction of bone microstructure . In addition, they have been applied in dental imaging to identify different tooth components, including the detection of caries lesions …”

Section: Introductionmentioning

confidence: 99%

Visualization of calcium phosphate cement in teeth by zero echo time ¹H MRI at high field

et al. 2017

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H magnetic resonance imaging (MRI) by a zero echo time (ZTE) sequence is an excellent method to image teeth. Calcium phosphate cement (CPC) materials are applied in the restoration of tooth lesions, but it has not yet been investigated whether they can be detected by computed tomography (CT) or MRI. The aim of this study was to optimize high-field ZTE imaging to enable the visualization of a new CPC formulation implanted in teeth and to apply this in the assessment of its decomposition in vivo. CPC was implanted in three human and three goat teeth ex vivo and in three goat teeth in vivo. An ultrashort echo time (UTE) sequence with multiple flip angles and echo times was applied at 11.7 T to measure T and T * values of CPC, enamel and dentin. Teeth with CPC were imaged with an optimized ZTE sequence. Goat teeth implanted with CPC in vivo were imaged after 7 weeks ex vivo. T * relaxation of implanted CPC, dentin and enamel was better fitted by a model assuming a Gaussian rather than a Lorentzian distribution. For CPC and human enamel and dentin, the average T * values were 273 ± 19, 562 ± 221 and 476 ± 147 μs, respectively, the average T values were 1234 ± 27, 963 ± 151 and 577 ± 41 μs, respectively, and the average T values were 1065 ± 45, 972 ± 40 and 903 ± 7 ms, respectively. In ZTE images, CPC had a higher signal-to-noise-ratio than dentin and enamel because of the higher water content. Seven weeks after in vivo implantation, the CPC-filled lesions showed less homogeneous structures, a lower T value and T * separated into two components. MRI by ZTE provides excellent contrast for CPC in teeth and allows its decomposition to be followed.

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Ultrashort echo time (UTE) MRI for the assessment of caries lesions

Cited by 55 publications

References 39 publications

Influence of pulse sequence parameters at 1.5 T and 3.0 T on MRI artefacts produced by metal–ceramic restorations

Influence of pulse sequence parameters at 1.5 T and 3.0 T on MRI artefacts produced by metal–ceramic restorations

Assessment of Apical Periodontitis by MRI: A Feasibility Study

Visualization of calcium phosphate cement in teeth by zero echo time ¹H MRI at high field

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Ultrashort echo time (UTE) MRI for the assessment of caries lesions

Cited by 55 publications

References 39 publications

Influence of pulse sequence parameters at 1.5 T and 3.0 T on MRI artefacts produced by metal–ceramic restorations

Influence of pulse sequence parameters at 1.5 T and 3.0 T on MRI artefacts produced by metal–ceramic restorations

Assessment of Apical Periodontitis by MRI: A Feasibility Study

Visualization of calcium phosphate cement in teeth by zero echo time 1H MRI at high field

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Visualization of calcium phosphate cement in teeth by zero echo time ¹H MRI at high field