title: Dose optimization of contrast-enhanced carotid MR angiography.
abstract: The purpose of this work was to compare the diagnostic performance of a single-contrast or a double-contrast dose of carotid contrast-enhanced MR angiography (MRA). One-hundred nineteen patients (mean age 65+/-14.4 years) underwent carotid contrast-enhanced MRA with a standardized protocol (repetition time/echo 3.73 ms/1.38 ms, flip-angle 25 degrees, acquisition-time 19 s, voxel size 1.2 x 1.2 x 0.9 mm3) on a 1.5-T scanner (Sonata, Siemens-Medical-Systems) using a neck phased-array coil. Contrast agent was administered intravenously at a rate of 3.0 ml/s, either as a single dose (n=57; 0.1 mmol/kg body weight) or as a double dose (n=62; 0.2 mmol/kg body weight) of meglumine gadoterate (0.5 M/l), followed by 30 ml saline. Qualitative image analysis was performed on maximum intensity projections using a five-point scale. Signal intensities were measured at three different vascular levels on both sides to assess the contrast-to-noise ratios (CNRs). Image quality was rated as good or excellent in all cases. A double dose did not influence the efficacy of carotid enhancement (CNR single dose 69.12+/-19.8; CNR double dose 70.01+/-20.7; p = 0.81) compared with a single dose. In both dose groups the mean CNRs were inversely related to bodyweight, despite adjusted contrast volumes (p=0.0005). Double-dose contrast-enhanced carotid MRA is not superior to single-dose MRA, as overall diagnostic performance and quantitative contrast enhancement are equal. Being more cost-efficient, a single-dose administration of contrast agent is recommended for MRA of the carotid arteries.
authors.affiliation: Cantonal Hospital Baden, Institute of Radiology, 5404, Baden, Switzerland. martin.unterweger@ksb.ch
authors.forename: M
authors.initials: M
authors.lastname: Unterweger
authors.forename: J M
authors.initials: JM
authors.lastname: Froehlich
authors.forename: R A
authors.initials: RA
authors.lastname: Kubik-Huch
authors.forename: B
authors.initials: B
authors.lastname: Seifert
authors.forename: M
authors.initials: M
authors.lastname: Birrer
authors.forename: T
authors.initials: T
authors.lastname: Huber
authors.forename: R
authors.initials: R
authors.lastname: Otto
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002339:Carotid Arteries / Q000473:pathology*; D016893:Carotid Stenosis / Q000175:diagnosis; D003287:Contrast Media / Q000008:administration & dosage*; D005260:Female; D005682:Gadolinium / Q000008:administration & dosage; D006571:Heterocyclic Compounds / Q000008:administration & dosage; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007275:Injections, Intravenous; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009942:Organometallic Compounds / Q000008:administration & dosage; D011446:Prospective Studies; D020521:Stroke / Q000175:diagnosis
chemical_list: D003287:Contrast Media; D006571:Heterocyclic Compounds; D009942:Organometallic Compounds; C050823:gadolinium 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetate; D005682:Gadolinium