Investig Magn Reson Imaging.  2019 Sep;23(3):202-209. 10.13104/imri.2019.23.3.202.

Ultrashort Echo Time MRI (UTE-MRI) Quantifications of Cortical Bone Varied Significantly at Body Temperature Compared with Room Temperature

Affiliations
  • 1Department of Radiology, University of California, San Diego, United States. jiangdu@ucsd.edu, sjerban@ucsd.edu
  • 2Radiology Service, VA San Diego Healthcare System, San Diego, United States.

Abstract

PURPOSE
To investigate the temperature-based differences of cortical bone ultrashort echo time MRI (UTE-MRI) biomarkers between body and room temperatures. Investigations of ex vivo UTE-MRI techniques were performed mostly at room temperature however, it is noted that the MRI properties of cortical bone may differ in vivo due to the higher temperature which exists as a condition in the live body.
MATERIALS AND METHODS
Cortical bone specimens from fourteen donors (63 ± 21 years old, 6 females and 8 males) were scanned on a 3T clinical scanner at body and room temperatures to perform T1, T2*, inversion recovery UTE (IR-UTE) T2* measurements, and two-pool magnetization transfer (MT) modeling.
RESULTS
Single-component T2*, IR-T2*, short and long component T2*s from bi-component analysis, and T1 showed significantly higher values while the noted macromolecular fraction (MMF) from MT modeling showed significantly lower values at body temperature, as compared with room temperature. However, it is noted that the short component fraction (Frac1) showed higher values at body temperature.
CONCLUSION
This study highlights the need for careful consideration of the temperature effects on MRI measurements, before extending a conclusion from ex vivo studies on cortical bone specimens to clinical in vivo studies. It is noted that the increased relaxation times at higher temperature was most likely due to an increased molecular motion. The T1 increase for the studied human bone specimens was noted as being significantly higher than the previously reported values for bovine cortical bone. The prevailing discipline notes that the increased relaxation times of the bound water likely resulted in a lower signal loss during data acquisition, which led to the incidence of a higher Frac1 at body temperature.

Keyword

Cortical bone; Magnetic resonance imaging; Ultrashort echo time; Body temperature

MeSH Terms

Biomarkers
Body Temperature*
Female
Humans
Incidence
Magnetic Resonance Imaging*
Relaxation
Tissue Donors
Water
Biomarkers
Water
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