The insertion of peripherally inserted central catheters (PICCs) represents a minimally invasive and safe method for establishing long-term central venous access in patients requiring prolonged intravenous therapy, including chemotherapy, parenteral nutrition, and long-term antibiotic treatment. Ultrasound-guided cannulation of peripheral arm veins improves procedural success, reduces complications, and increases patient comfort compared with centrally inserted central catheters.Accurate positioning of the catheter tip at the cavo-atrial junction is essential for optimal catheter function and safety. The Sherlock 3CG Tip Confirmation System combines electromagnetic tracking with intracavitary electrocardiography (ECG) to enable real-time catheter tip navigation and positioning.The aim of this prospective clinical study is to evaluate the accuracy and safety of ultrasound-guided PICC insertion using the Sherlock 3CG system, as well as to assess the impact of PICC placement on venous wall integrity. Ultrasound examination of the target vein will be performed before catheter insertion and after catheter removal to evaluate potential vascular wall changes associated with catheter use. A chest X-ray examination will be performed after each catheter insertion to confirm final catheter tip position and to assess the accuracy of the navigation system.Fluoroscopic guidance will be used only in selected cases, such as patients with anatomical anomalies, previously known difficult vascular access, or unsuccessful standard catheter advancement.A total of 80 adult patients with a clinical indication for PICC placement will be enrolled over a three-year study period.

Peripherally inserted central catheters (PICCs) have been widely used for many years as reliable central venous access devices in patients requiring prolonged intravenous therapy. Traditionally, catheter tip positioning is confirmed using fluoroscopy or chest radiography, which exposes patients to ionizing radiation and may increase procedural time and costs. Technological advances such as the Sherlock 3CG Tip Confirmation System allow real-time catheter navigation and tip positioning using electromagnetic tracking and intracavitary ECG.The primary objective of this prospective single-center clinical study is to evaluate the safety and effectiveness of ultrasound-guided PICC insertion using the Sherlock 3CG system. An additional objective is to assess the effect of PICC placement on venous wall integrity using ultrasound imaging before catheter insertion and after catheter removal.Adult patients (>18years) with sinus rhythm in the absence of an implanted cardiac pacing device and a medical indication for PICC placement, including chemotherapy, parenteral nutrition, or prolonged intravenous therapy, will be eligible for enrollment. After obtaining written informed consent, patients will undergo pre-procedural ultrasound examination to assess venous anatomy, vessel diameter, and baseline vascular wall characteristics.PICC insertion will be performed under sterile conditions using ultrasound guidance and the Seldinger technique. Cannulation will be performed in one of the upper-arm veins (basilic, brachial, or cephalic vein). Local anesthesia will be administered prior to venipuncture. Catheter tip navigation and positioning at the cavo-atrial junction will be performed using the Sherlock 3CG system with intracavitary ECG guidance.A chest X-ray examination will be performed after each catheter insertion to document the final catheter tip position and to evaluate the accuracy of the Sherlock 3CG system. Fluoroscopic guidance will not be routinely used but will be reserved for cases with suspected anatomical anomalies, previously documented difficult vascular access, or unsuccessful catheter advancement using the standard approach.Procedure duration, success rate, and any intra-procedural or post-procedural complications will be recorded. Following completion of therapy and catheter removal, patients will undergo repeat ultrasound examination to assess venous wall characteristics, including wall thickness, structural changes, and potential complications such as thrombosis or fibrosis. Baseline and follow-up findings will be compared.Participants will be followed according to clinical routine throughout catheter dwell time, and complications such as infection, thrombosis, catheter malfunction, or mechanical issues will be documented.The study will begin on March 1, 2026, with an estimated duration of three years. A total of 80 patients are planned to be enrolled.The results of this study are expected to provide evidence regarding the accuracy and safety of the Sherlock 3CG system, its impact on vascular wall integrity, and its role in optimizing vascular access procedures in clinical practice.

Inclusion Criteria:

• sinus rhythm
• medical indication
• suitable upper-extremity venous anatomy confirmed by ultrasound examination
• ability to provide written informed consent

Exclusion Criteria:

• Implanted cardiac pacing device
• Palliative care
• <18years old
• Local infection, skin lesion, or burn at the intended insertion site
• Severe coagulopathy contraindicating vascular access procedures
• Known allergy to catheter materials or local anesthetics used during the procedure
• Presenceof an implanted cardiac pacemaker or non-sinus cardiac rhythm preventing reliable intracavitary ECG guidance
• Anatomical abnormalities preventing safe PICC insertion
• Previous lymphadenectomy on the intended side
• Pre-existing venous thrombosis or significant venous wall pathology detected on baseline ultrasound

Adult patients (>18years) with sinus rhythm in the absence of an implanted cardiac pacing device and a medical indications for PICC placement, including oncologic therapy, parenteral nutrition, or prolonged intravenous treatment, will be considered eligible for participation. All participants will provide written informed consent prior to enrollment.