Magnetization transfer based contrast for imaging denatured collagen.
OBJECTIVE
To study of the sensitivity of various NMR and MRI methods and parameters to the degree of thermal denaturation of collagen.


METHODS
Collagen type I powder was washed with methanol:chloroform to remove traces of lipids and then suspended in saline. Denaturation was carried out by heating the suspension for 5-120 minutes at a temperature range of 50-100 degrees C. The NMR methods tested were two T(2) filter methods: Goldman-Shen (GS) and Edzes-Samulski (ES); magnetization transfer contrast (MTC); double quantum filtering (DQF) and high resolution spectroscopy. MRI contrasts based on these methods were compared.


RESULTS
The following parameters were found to be sensitive to denaturation of collagen: 1) the amount of spins that experience high dipolar interactions as assessed by DQF; 2) MTR; 3) k(w)T(1w) (where k(w) is the magnetization transfer rate from water to collagen, and T(1w) is the water protons longitudinal relaxation time); and 4) aliphatic residues content. The contrast between native and denatured collagen was improved by all the tested methods, with ES and DQF producing the highest contrast.


CONCLUSIONS
Methods depending on T(2) filtering and DQF were found to be sensitive to the degree of thermal denaturation of collagen and improve the contrast between native and denatured collagen.
Harel
Amir
A
Department of Medical Physics, Tel Aviv University, Tel Aviv, Israel.
Eliav
Uzi
U
Akselrod
Solange
S
Navon
Gil
G
D000818:Animals; D002417:Cattle; D003094:Collagen / Q000737:chemistry*; D006358:Hot Temperature; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D011489:Protein Denaturation; D013816:Thermodynamics; D013997:Time Factors
D003094:Collagen