title: Development of a universal dual-bolus injection scheme for the quantitative assessment of myocardial perfusion cardiovascular magnetic resonance.
abstract: BACKGROUND
  The dual-bolus protocol enables accurate quantification of myocardial blood flow (MBF) by first-pass perfusion cardiovascular magnetic resonance (CMR). However, despite the advantages and increasing demand for the dual-bolus method for accurate quantification of MBF, thus far, it has not been widely used in the field of quantitative perfusion CMR. The main reasons for this are that the setup for the dual-bolus method is complex and requires a state-of-the-art injector and there is also a lack of post processing software. As a solution to one of these problems, we have devised a universal dual-bolus injection scheme for use in a clinical setting. The purpose of this study is to show the setup and feasibility of the universal dual-bolus injection scheme.
  
  
  METHODS
  The universal dual-bolus injection scheme was tested using multiple combinations of different contrast agents, contrast agent dose, power injectors, perfusion sequences, and CMR scanners. This included 3 different contrast agents (Gd-DO3A-butrol, Gd-DTPA and Gd-DOTA), 4 different doses (0.025 mmol/kg, 0.05 mmol/kg, 0.075 mmol/kg and 0.1 mmol/kg), 2 different types of injectors (with and without "pause" function), 5 different sequences (turbo field echo (TFE), balanced TFE, k-space and time (k-t) accelerated TFE, k-t accelerated balanced TFE, turbo fast low-angle shot) and 3 different CMR scanners from 2 different manufacturers. The relation between the time width of dilute contrast agent bolus curve and cardiac output was obtained to determine the optimal predefined pause duration between dilute and neat contrast agent injection.
  
  
  RESULTS
  161 dual-bolus perfusion scans were performed. Three non-injector-related technical errors were observed (1.9%). No injector-related errors were observed. The dual-bolus scheme worked well in all the combinations of parameters if the optimal predefined pause was used. Linear regression analysis showed that the optimal duration for the predefined pause is 25s to separate the dilute and neat contrast agent bolus curves if 0.1 mmol/kg dose of Gd-DO3A-butrol is used.
  
  
  CONCLUSIONS
  The universal dual-bolus injection scheme does not require sophisticated double-head power injector function and is a feasible technique to obtain reasonable arterial input function curves for absolute MBF quantification.
authors: Division of Imaging Sciences, The Rayne Institute, London, UK. ishidamasaki1@gmail.com
authors: Masaki
authors: M
authors: Ishida
authors: Andreas
authors: A
authors: Schuster
authors: Geraint
authors: G
authors: Morton
authors: Amedeo
authors: A
authors: Chiribiri
authors: Shazia
authors: S
authors: Hussain
authors: Matthias
authors: M
authors: Paul
authors: Nico
authors: N
authors: Merkle
authors: Henning
authors: H
authors: Steen
authors: Dirk
authors: D
authors: Lossnitzer
authors: Bernhard
authors: B
authors: Schnackenburg
authors: Khaled
authors: K
authors: Alfakih
authors: Sven
authors: S
authors: Plein
authors: Eike
authors: E
authors: Nagel
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