Dose optimization of contrast-enhanced carotid MR angiography

• Published in: European radiology 2005-09, Vol.15 (9), p.1797-1805
• Main Authors: Unterweger, M, Froehlich, J M, Kubik-Huch, R A, Seifert, B, Birrer, M, Huber, T, Otto, R
• Format: Article
• Language: English
• Subjects: Adult; Aged; Aged, 80 and over; Angiography; Body weight; Carotid arteries; Carotid Arteries - pathology; Carotid artery; Carotid Stenosis - diagnosis; Contrast agents; Contrast media; Contrast Media - administration & dosage; Diagnostic systems; Female; Gadolinium - administration & dosage; Heterocyclic Compounds - administration & dosage; Humans; Image analysis; Image contrast; Image enhancement; Image Enhancement - methods; Image processing; Image Processing, Computer-Assisted - methods; Image quality; Injections, Intravenous; Magnetic Resonance Angiography - methods; Male; Medical imaging; Middle Aged; Organometallic Compounds - administration & dosage; Prospective Studies; Qualitative analysis; Stroke - diagnosis
• ISSN: 0938-7994; 1432-1084
• DOI: 10.1007/s00330-005-2756-3

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.