Dual mechanisms for change in myocardial signal intensity by means of a single MR contrast medium: dependence on concentration and pulse sequence.
To determine whether gadodiamide injection can provide sufficient enhancement on both T1- and T2-weighted spin-echo magnetic resonance (MR) images of the heart and skeletal muscles, anesthetized rats were divided into five groups. Groups 1-3 received 0.1 (n = 9), 0.3 (n = 8), or 0.5 (n = 8) mmol/kg gadodiamide injection, respectively, and T1-weighted images were obtained. Groups 4 and 5 received 0.3 or 0.5 mmol/kg gadodiamide injection, respectively, and T2-weighted images were obtained. Gadolinium concentration was measured in myocardium by means of inductively coupled plasma-atomic emission spectroscopy. On T1-weighted images, the 0.1 and 0.3 mmol/kg doses produced a dose-dependent increase in myocardial signal intensity proportional to gadolinium concentration. A dose of 0.5 mmol/kg, which correlated with higher gadolinium concentration and did not further increase myocardial signal intensity, prolonged the imaging window. On T2-weighted images, the 0.3 mmol/kg dose caused a transient decrease in myocardial signal intensity; the 0.5 mmol/kg dose produced greater and persistent loss of signal intensity. In conclusion, the changes in signal intensity induced by gadodiamide injection depend on the dose, pulse sequence, and type of tissue.
Saeed
M
M
Department of Radiology, University of California, San Francisco 94143-0628.
Wendland
M F
MF
Masui
T
T
Yu
K K
KK
Li
J J
JJ
Derugin
N
N
Higgins
C B
CB
D000818:Animals; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006321:Heart / Q000033:anatomy & histology*; D008279:Magnetic Resonance Imaging / Q000379:methods; D009132:Muscles / Q000033:anatomy & histology; D009942:Organometallic Compounds; D004369:Pentetic Acid; D051381:Rats; D017207:Rats, Sprague-Dawley
D003287:Contrast Media; D009942:Organometallic Compounds; D004369:Pentetic Acid; C064925:gadodiamide; D019786:Gadolinium DTPA