Postoperative liver failure (PLF) is the major cause of morbidity after liver resection (1,2). The risk of PLF is linked to the future liver remnant (FLR) (3), although liver volume and function are not always proportional (4). Therefore, the estimation of the preoperative FLR is mandatory in major hepatectomy as for staged procedures (5,6). As alternative, for ensuring adequate FLR, parenchyma-sparing major hepatectomies have been proposed (10-13), including detachment of major intrahepatic vessels from CLM (R1vasc) which proved to be oncologically suitable (14). Given that, major hepatectomy has been reduced (15-16). However, the FLR estimation in complex parenchyma-sparing hepatectomy for multiple bilobar and deep-located CLMs is unfeasible just adopting hand trace technique. Three-dimensional (3D) virtual cast has shown facilitating the FLR estimation (17-19). Recently, 3D modelling to estimate the FLR in the peculiar setting of ultrasound guided R1vasc approach has been introduced (20). That adding standardization could enhance the clinical reliability, reproducibility, and then safety of ultrasound guided R1vasc surgery. References 1. Mullen JT, et al. (2007) J Am Coll Surg 204:854–862. 2. Vibert E, et al. (2014) Surgery 155:94–105. 3. Schroeder RA, et al. (2006).Ann Surg 243:373–379. 4. Chuang YH, et al. (2018) Liver Int 38:868-874. 5. Jaeck D, et al. (2004) Ann Surg 240:1037-49. 6. Schnitzbauer AA, et al. (2012) Ann Surg 25:405-14. 7. Torzilli G, et al. (2017) HPB (Oxford). 19(9): 775-784. 8. Mise Y, et al (2016) Ann Surg 263:146-152. 9. Matsuki R, et al. (2016) Surgery 160:1256-1263. 10.Torzilli G, et al. (2009) Surgery 146: 60–71. 11. Torzilli G, et al. (2018) Dig Surg 35:323-332. 12. Torzilli G, et al. (2019). HPB (Oxford). 21(10): 1411-1418 13. Torzilli G. 2021. (2021) Br J Surg, 12;108(2):109-111 14. Viganò L, et al. (2016) Ann Surg Oncol 23:1352-60. 15. Torzilli G, et al. (2018) Surgery 163:277-284. 16. Torzilli G. Ultrasound guided liver surgery. Springer 2014 17. Nakayama K, et al. (2017) World J Surg 41:1840-1847. 18. Mise Y, et al. (2018) Ann Surg 268:127-133. 19. Takamoto T, et al. (2018) J Gastrointest Surg 22:2037-2044. 20. Procopio F, et al. HPB (Oxford). 2021;23(7):1084-1094