title: Improved quality and diagnostic confidence achieved by use of dose-reduced gadolinium blood-pool agents for time-resolved intracranial MR angiography.
abstract: OBJECTIVE
  Time-resolved MRA with the use of bolus injection of paramagnetic agents has proved valuable in neurovascular imaging. Standard contrast agents have limited blood-pool residence times, motivating the development of highly protein-bound blood-pool agents with greater relaxivity and longer intravascular residence, affording improved image quality at lesser doses. This study represents the first comparison of blood-pool agents to standard agents in time-resolved cerebral MRA.
  
  
  METHODS
  One hundred datasets were acquired at 1.5 T by use of a standardized, time-resolved MRA protocol. Patients received either unit dosing of a standard extracellular agent at 0.1 mmol/kg or a blood-pool agent at 0.03 mmol/kg. Peak arterial and venous enhancement phases were identified and subsequently scored qualitatively by use of a 4-point Likert scale, with attention to 6 vascular segments: 1) intracranial ICA; 2) MCA M1; 3) MCA M2; 4) MCA M3; 5) deep cerebral veins; and 6) dural venous sinuses.
  
  
  RESULTS
  Fifty MR angiographies were acquired with each agent. No significant differences were found between agents in generation of uncontaminated arteriograms. Blood-pool agents, at 67% dose reduction, were of significantly greater quality across most vascular segments, including ICA (P = .019), M2 (P = .003), and M3 (P < .01). Superiority in the M1 segment approached significance (P = .059). Significantly better venographic quality was noted for deep venous structures (P = .016) with the use of blood-pool agents.
  
  
  CONCLUSIONS
  Blood-pool agents provide superior demonstration of most intracranial vessels in time-resolved MRA compared with standard agents, at reduced doses. The greater relaxation enhancement and more favorable dosing profile make blood-pool agents superior to standard agents for use in cerebral time-resolved MRA.
authors: From Neuroradiology Division, Department of Radiology and Imaging Sciences (S.D., A.M.S.), Emory University Hospital, Atlanta, Georgia.
authors: S
authors: S
authors: Dehkharghani
authors: J
authors: J
authors: Kang
authors: A M
authors: AM
authors: Saindane
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D005260:Female; D005682:Gadolinium; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008536:Meglumine / Q000031:analogs & derivatives*; D008875:Middle Aged; D059906:Neuroimaging / Q000379:methods*; D009942:Organometallic Compounds; D058996:Quality Improvement; D011829:Radiation Dosage; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013997:Time Factors; D055815:Young Adult
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C064572:gadobenic acid; D008536:Meglumine; D005682:Gadolinium; C109932:gadofosveset trisodium
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