title: In vivo tumor lactate relaxation measurements by selective multiple-quantum-coherence (Sel-MQC) transfer.
abstract: The frequency-selective multiple-quantum-coherence (Sel-MQC) lactate (Lac) filter offers complete lipid and water suppression in a single scan for robust in vivo detection of tumor Lac, even in the presence of abundant lipids. Conversion of the detected signal into accurate tissue concentrations of Lac requires knowledge of in vivo Lac T1 and T2 relaxation times. This work reports modifications to the Sel-MQC pulse sequence, T1- and T2-Sel-MQC, that facilitate relaxation measurements of Lac. The T1-Sel-MQC sequence combines an inversion prepulse with the Sel-MQC filter. The T2-Sel-MQC sequence incorporates a CH3-selective 180 degrees pulse during the MQ preparation period to overcome the J-modulation effects and allow the insertion of variable echo delays. The performance of these sequences was evaluated with the use of phantoms and subcutaneous murine tumor models in vivo. The present approach will allow investigators to correct for the relaxation-induced Lac signal loss in Sel-MQC experiments for the quantitative mapping of in vivo tumor Lac distribution.
authors.affiliation: Department of Medical Physics and Radiology, Memorial Sloan-Kettering Cancer Center, New York, New York, USA.
authors.forename: Manickam
authors.initials: M
authors.lastname: Muruganandham
authors.forename: Jason A
authors.initials: JA
authors.lastname: Koutcher
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Pizzorno
authors.forename: Qiuhong
authors.initials: Q
authors.lastname: He
mesh_terms: D000818:Animals; D003110:Colonic Neoplasms / Q000737:chemistry*; D007773:Lactates / Q000032:analysis*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008325:Mammary Neoplasms, Experimental / Q000737:chemistry*; D051379:Mice; D008809:Mice, Inbred C3H; D019047:Phantoms, Imaging
chemical_list: D007773:Lactates