Fig. 2
Temperature experiments (i) performed at two national metrology institutes: the US National Institute of Standards and Technology (NIST) laboratory after 1 year on six loose tubes from T1MES and at Physikalisch-Technische Bundesanstalt (PTB) on phantom 30E012. ii and iii indicate to which field-strength device the tested tubes belong. At NIST, T1 and T2 were measured on a Varian/Agilent small bore scanner operating at 1.5 T in a temperature-controlled environment. Temperatures were measured using a fiber optic probe. At PTB, T1 and T2 were measured on a 3 T MAGNETOM Verio scanner (Siemens Healthineers; software syngo MR B17A). The phantom was always stored, moved, and scanned while resting in a Styrofoam box to ensure that the temperatures picked at bottle hull reflects the tube temperature. At scan time, the box was placed in the head coil (12 ch) of the PTB 3 T scanner. Temperatures were measured using a Pt100 resistance thermometer. Similar to temperature dependency results immediately after phantom manufacture, [5] short-T1 tubes (modeling post-GBCA myocardium and blood) are more stable with temperature than very long-T1 tubes (native blood) where T1 increases more significantly with temperature