Dental MRI: imaging of soft and solid components without ionizing radiation.
OBJECTIVE
To evaluate the ability of conventional and ultra-short or zero echo time MRI for imaging of soft and solid dental components in and ex vivo.


METHODS
Turbo spin echo (TSE), ultra-short echo time (UTE), and zero echo time (ZTE) MRI were performed on extracted (human and equine) teeth and in vivo using whole-body and small-bore MR systems at 3 T, 7T, and 9.4T, respectively.


RESULTS
At an isotropic resolution of (600 μm)(3) , strong signal of soft-tissue, e.g., mucosa and nerves with excellent contrast was achieved using TSE at 3T in vivo. No signal, though, was obtained from solid components, e.g., teeth (due to short T(2) ). In contrast, dentin, cementum as well as enamel of extracted teeth were readily depicted using UTE and ZTE at a resolution of ≈ (150 μm)(3) at 7T and 9.4T. In particular, ZTE provided higher signal in enamel.


CONCLUSIONS
As an alternative to X-ray based methods like cone-beam computed tomography (CT) or conventional CT, the presented results demonstrate the potential of ZTE and UTE MRI as a radiation-free imaging modality, delivering contrast of soft and solid components at the same time.
Department of Radiology - Medical Physics, University Medical Center, Freiburg, Germany. jan.hoevener@uniklinik-freiburg.de
Jan-Bernd
JB
Hövener
Stefan
S
Zwick
Jochen
J
Leupold
Anne-Katrin
AK
Eisenbeiβ
Christian
C
Scheifele
Frank
F
Schellenberger
Jürgen
J
Hennig
Dominik V
DV
Elverfeldt
Ute
U
Ludwig
D003238:Connective Tissue / Q000473:pathology*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008963:Molar / Q000473:pathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014076:Tooth Diseases / Q000473:pathology*