A male in his 70s underwent laparoscopic-assisted high anterior resection and D2 lymph node dissection for rectal cancer (pT3, pN1a, M0, fStage ⅢB)3 years ago. Postoperative adjuvant chemotherapy was not administered due to diabetic nephropathy. Three years post-surgery, plain CT and PET-CT revealed recurrent liver metastasis at the bifurcation of the anterior and posterior liver segments. Right hepatic lobectomy was planned following portal vein embolization, as his ICG R15 was 18.9%, indicating insufficient residual liver volume after resection. To avoid frequent contrast-enhanced CT scans due to low renal function, 4D flow-MRI was performed before portal vein embolization and on the third day post-embolization to measure portal blood flow velocity and volume. These measurements were applied to the estimated residual liver volume formula to predict the residual liver volume 28 days later. The predicted residual liver volume on the 28th day was 469 mL(64%), and CT volumetry performed on the same day showed a volume of 471 mL. Right hepatic lobectomy was performed without worsening liver or kidney function. This case report demonstrates that using 4D flow-MRI can accurately predict the residual liver volume after portal vein embolization, enabling safe curative resection in patients for whom contrast-enhanced CT is challenging due to renal impairment.