When a healthcare provider finds that a patient on hemodialysis has difficulty suctioning with a syringe attached to a permanent central venous catheter and no significant resistance to gently pushing saline through the guide tube, it is important to consider that the patient has a peritubular fibrous sheath that may interfere with the normal use of the catheter. Peritubular fibrous sheaths are difficult to remove with the removal of the central venous catheter. Two imaging methods are used for the diagnosis of periportal fibrous sheaths: 1) to remove the catheter, ultrasound still indicates the presence of annular floaters in the lumen of the vein, and the deep vein in which the catheter is placed remains open to blood flow, with the annulus extending mostly along the entrance of the internal jugular vein catheter toward the subcutaneous tunnel of the catheter; 2) to withdraw the catheter externally after freeing the catheter cuff and re-injecting the contrast agent along the line, which does not diffuse into the central vein through the end of the catheter, but The contrast agent does not diffuse through the end of the catheter into the central vein, but extends in a linear pattern along the original catheter alignment. The above imaging examinations suggest the formation of peri-catheter fibrous sheath.