Optimark

MRI examinations were conducted on 1.5T or 3T MRI scanners including Signa Excite^®, GE Discovery^®, Siemens Aera^®, Espree^®, Verio^®, Avanto^®, Skyra^®, and Trio Tim^® scanners. Non-contrast T1 images were acquired in all patients prior to administration of intravenous contrast. After the administration of intravenous gadolinium-based contrast agent (including Gadavist^® (Bayer), Dotarem^® (Guerbet), Magnevist^® (Bayer), ProHance^® (Bracco Diagnostics), and Optimark^® (Covidien), dosed at 0.1 mmol/kg), three T1-weighted three-dimensional (3D) gradient-echo (GRE) breath-hold imaging series (acquisition times of 12-18s, with fat suppression) were acquired reflecting CT/MRI LI-RADS recommendations: (1) late arterial, (2) portal venous and (3) delayed or equilibrium phase. Bolus tracking was applied in a large proportion of patients. Imaging parameters were in the range of TR 3-5 ms, TE 1-2 ms, flip angle 9-13 degrees, bandwidth 300-500 Hz, slice thickness 3-4 mm, image matrix 256 x 132 to 320 x 216, and field-of-view 300 x 200 mm to 500 x 400 mm. If a patient received multiple MRI scans, then the MRI performed closest to the date of pathological confirmation was used.

This study involved MRI examinations performed from 2010 to 2017 available throughout the institutional PACS, designed to include a heterogeneous collection of MRI scanners and imaging studies. This incorporated both 1.5-Tand 3-T MR scanners, including Siemens Aera, Espree, Verio, Avanto, Skyra, and Trio Tim and GE Discovery and Signa Excite scanners. Multi-phasic contrast-enhanced T1-weighted breath-hold sequences from standard institutional liver MR imaging protocols were used with acquisition times of 12–18 s. Several different gadolinium-based contrast agents were used (dosed at 0.1 mmol/kg), including Dotarem (Guerbet), Gadavist (Bayer), Magnevist (Bayer), ProHance (Bracco Diagnostics), and Optimark (Covidien). Post-contrast images were analyzed, including late arterial phase (~20 s post-injection), portal venous phase(~70spost-injection),anddelayedvenousphase(~3min post-injection). Imaging parameters varied across different scanners and time frames; however, the majority were in the range of TR 3–5 ms, TE 1–2 ms, flip angle 9–13°, bandwidth 300– 500 Hz, slice thickness 3–4 mm, image matrix 256 × 132 to 320 ×216, and field-of-view 300 ×200 mm to 500 ×400 mm.