Absolute temperature MR imaging with thulium 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetramethyl-1,4,7,10-tetraacetic acid (TmDOTMA-).
MR thermometry based on the water (1)H signal provides high temporal and spatial resolution, but it has low temperature sensitivity (approximately 0.01 ppm/degrees C) and requires monitoring of another weaker signal for absolute temperature measurements. The use of the paramagnetic lanthanide complex, thulium 1,4,7,10- tetraazacyclododecane-1,4,7,10-tetramethyl-1,4,7,10-tetraacetate (TmDOTMA(-)), which is approximately 60 times more sensitive to temperature than the water (1)H signal, is advanced to image absolute temperatures in vivo using water signal as a reference. The temperature imaging technique was developed using gradient echo and asymmetric spin echo imaging sequences on 9.4 Tesla (T) horizontal and vertical MR scanners. A comparison of regional temperatures measured with TmDOTMA(-) and fiber-optic probes showed that the accuracy of imaging temperature is <0.3 degrees C. The temperature imaging technique was found to be insensitive to inhomogeneities in the main magnetic field. The feasibility of imaging temperature of intact rats at approximately 1.4 mmol/kg dose with approximately 1-mm spatial resolution in only 3 min is demonstrated. TmDOTMA(-) should prove useful for imaging absolute temperatures in deep-seated organs in numerous biomedical applications.
James
Judy R
JR
Department of Radiology, Indiana University School of Medicine, Indianapolis, IN 46202-5181, USA.
Gao
Yong
Y
Miller
Michael A
MA
Babsky
Andriy
A
Bansal
Navin
N
D000465:Algorithms; D000818:Animals; D001831:Body Temperature / Q000502:physiology*; D003287:Contrast Media; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009942:Organometallic Compounds; D051381:Rats; D011916:Rats, Inbred F344; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013817:Thermography / Q000379:methods*; D051598:Whole Body Imaging / Q000379:methods*
D003287:Contrast Media; D009942:Organometallic Compounds; C463281:thulium-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate