title: Inversion recovery EPI of bolus transit in rat myocardium using intravascular and extravascular gadolinium-based MR contrast media: dose effects on peak signal enhancement.
abstract: Inversion recovery gradient recalled echo planar imaging (TI/TR/TE = 700/2000/10 ms) was used to dynamically monitor the first pass of an intravascular (GdDOTA-polylysine) and an extravascular (GdDTPA-BMA) contrast agent through normal rat myocardium. It was found that myocardial enhancement increased with dose of the intravascular agent to a limiting value of approximately 50% of fully relaxed intensity, consistent with enhancement of 40% of myocardial water content during the first pass. Larger doses produced no further increase in peak response. On the other hand, the extravascular agent caused incrementally increased enhancement throughout the dose range examined to a final value of 68 +/- 2% of fully relaxed intensity. The profile of dose dependence for both agents was inconsistent with monoexponential T1 relaxation. It was concluded that: (a) compartmentalization of myocardial water combined with restricted myocardial water diffusion limits the peak response during bolus transit; (b) extraction of the extravascular agent during transit elevates the peak response over that obtained from agent confined to the vascular volume; and (c) models that assume simple monoexponential T1 relaxation to derive time-density curves do not adequately describe the relationship between changes in signal intensity, R1 and contrast concentration.
authors.affiliation: Department of Radiology, University of California, San Francisco 94143-0628.
authors.forename: M F
authors.initials: MF
authors.lastname: Wendland
authors.forename: M
authors.initials: M
authors.lastname: Saeed
authors.forename: K K
authors.initials: KK
authors.lastname: Yu
authors.forename: T P
authors.initials: TP
authors.lastname: Roberts
authors.forename: K
authors.initials: K
authors.lastname: Lauerma
authors.forename: N
authors.initials: N
authors.lastname: Derugin
authors.forename: J
authors.initials: J
authors.lastname: Varadarajan
authors.forename: A D
authors.initials: AD
authors.lastname: Watson
authors.forename: C B
authors.initials: CB
authors.lastname: Higgins
mesh_terms: D000418:Albumins / Q000008:administration & dosage; D000818:Animals; D001834:Body Water / Q000378:metabolism; D003287:Contrast Media / Q000008:administration & dosage / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D017352:Echo-Planar Imaging; D005260:Female; D005682:Gadolinium / Q000008:administration & dosage / Q000097:blood / Q000378:metabolism; D019786:Gadolinium DTPA; D006207:Half-Life; D006352:Heart Ventricles / Q000378:metabolism / Q000473:pathology; D006571:Heterocyclic Compounds / Q000008:administration & dosage / Q000097:blood / Q000378:metabolism; D007089:Image Enhancement / Q000379:methods*; D007091:Image Processing, Computer-Assisted; D007275:Injections, Intravenous; D009206:Myocardium / Q000378:metabolism / Q000473:pathology*; D009942:Organometallic Compounds / Q000008:administration & dosage / Q000097:blood / Q000378:metabolism; D004369:Pentetic Acid / Q000008:administration & dosage / Q000031:analogs & derivatives; D011107:Polylysine / Q000008:administration & dosage / Q000031:analogs & derivatives*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014018:Tissue Distribution
chemical_list: D000418:Albumins; D003287:Contrast Media; D006571:Heterocyclic Compounds; D009942:Organometallic Compounds; C058946:albumin-(gadolinium-DTPA); C069063:polylysine-(Gd-DOTA); D011107:Polylysine; D004369:Pentetic Acid; C064925:gadodiamide; C050823:gadolinium 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetate; D005682:Gadolinium; D019786:Gadolinium DTPA