Grosse U, Syha R, Papanikolaou D, Martirosian P, Grözinger G, Schabel C, Schick F, Springer F. Magnetic resonance imaging of solid dental restoration materials using 3D UTE sequences: visualization and relaxometry of various compounds.
MAGMA 2013;
26:555-64. [PMID:
23525675 DOI:
10.1007/s10334-013-0373-8]
[Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Revised: 02/19/2013] [Accepted: 02/20/2013] [Indexed: 10/27/2022]
Abstract
OBJECT
Due to an increasing scientific interest in MR-imaging of carious lesions and teeth, an accurate signal characterization of dental restoration materials is necessary for optimization of MR sequence protocols and evaluation of material degradation. Therefore, signal yield and relaxation behavior of common dental restoration materials in comparison to those of dentine of extracted human teeth were assessed in vitro by ultrashort echo time (UTE) sequences.
MATERIALS AND METHODS
Eighteen material samples and dentine of two freshly extracted human teeth were investigated on a 3T whole-body clinical MR-scanner. Transverse (T2*) and longitudinal relaxation times (T1) were quantified using a recently published modified Ernst equation that takes relevant in-pulse relaxation effects into account.
RESULTS
All investigated samples could be successfully visualized but maximum signal yield was highly variable between samples. T1-values of the investigated dental restoration materials ranged between 28 and 365 ms, whereas T2*-values ranged between 96 and 917 μs. In contrast, T1-values of dentine (T1=545 ms±299 ms) were higher, while T2*-values (T2*=478 μs±271 μs) showed similar values.
CONCLUSIONS
Dental restoration materials and dentine of extracted human teeth can be visualized by UTE sequences and show a broad range of signal yield and relaxation times.
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