Radial artery puncture is commonly used to obtain vascular access for cerebral angiography and neurointerventional procedures. Conventional ultrasound guidance usually provides either a short-axis or a long-axis view of the radial artery. A biplanar handheld ultrasound system can provide simultaneous long-axis and short-axis views, which may help the operator visualize the puncture needle and radial artery more clearly.

This prospective, single-center, randomized, parallel-group superiority trial will compare the TUOREN biplanar handheld ultrasound system with a conventional high-frequency linear-array ultrasound system for ultrasound-guided radial artery puncture. A total of 152 adults scheduled to undergo cerebral angiography or neurointerventional treatment through a transradial approach will be randomly assigned in a 1:1 ratio to one of the two ultrasound-guidance groups.

The main objective is to determine whether biplanar handheld ultrasound guidance improves the percentage of participants with successful radial artery cannulation on the first puncture attempt. Other assessments include the total number of puncture attempts, cumulative active puncture time, fixation time after successful cannulation, and the occurrence of posterior wall puncture.

Ultrasound guidance is used to improve visualization of the radial artery during vascular access. Conventional high-frequency linear-array ultrasound systems provide either a short-axis or a long-axis image, depending on probe orientation and puncture technique. During puncture, the operator may need to adjust the probe repeatedly to maintain visualization of the needle tip and its position relative to the radial artery.

The TUOREN biplanar handheld ultrasound system uses a T-shaped dual-probe configuration to display simultaneous long-axis and short-axis views of the radial artery and puncture needle. The long-axis view is intended to show the needle trajectory and advancement, while the short-axis view is intended to show the lateral position of the needle relative to the vessel.

This is a prospective, randomized, parallel-group, single-center superiority trial conducted at Shanghai Fourth People's Hospital. Eligible participants scheduled for cerebral angiography or neurointerventional treatment through a transradial approach will be allocated in a 1:1 ratio using block randomization with allocation concealment.

Participants in the experimental group will undergo radial artery puncture guided by the TUOREN biplanar handheld ultrasound system. Participants in the active comparator group will undergo radial artery puncture guided by a conventional high-frequency linear-array ultrasound system using either a short-axis out-of-plane technique or a long-axis in-plane technique. Other components of the radial artery cannulation procedure will be standardized between the two groups.

The study is designed to evaluate whether simultaneous biplanar ultrasound visualization improves first-attempt radial artery cannulation success and procedural efficiency compared with conventional ultrasound guidance. Puncture attempts, procedure-related time intervals, and ultrasound findings will be recorded according to prespecified study definitions.

Inclusion Criteria:

1. Adults aged 18 years or older, regardless of sex, who are scheduled to undergo cerebral angiography or neurointerventional treatment through a transradial approach.
2. Adequate collateral circulation between the radial and ulnar arteries, as demonstrated by the modified Allen test or vascular ultrasound.
3. Radial artery diameter of at least 1.5 mm on preprocedural ultrasound examination.
4. Ability to understand the study procedures, willingness to participate voluntarily, and provision of written informed consent.

Exclusion Criteria:

1. Infection or skin damage at the intended puncture site; known radial artery occlusion or severe stenosis; or inadequate collateral circulation between the radial and ulnar arteries.
2. Radial artery diameter of less than 1.5 mm on preprocedural ultrasound examination, or severe radial artery tortuosity or anatomical variation that may interfere with the puncture procedure.
3. Previous puncture, surgery, or trauma involving the radial artery on the intended puncture side that may have altered the local anatomy.
4. Hemodynamic instability requiring urgent hemodynamic support, including cardiogenic shock or severe hypotension.
5. Impaired consciousness, psychiatric illness, or any other condition that prevents the participant from cooperating with the study procedures or completing the required follow-up.
6. Severe coagulation abnormality, defined as an international normalized ratio greater than 1.8 or a platelet count below 80 × 10^9/L.

Because the two ultrasound systems are visibly different, the operator and the on-site observer recording puncture attempts and procedure times cannot be masked. Posterior wall puncture may be independently adjudicated using coded ultrasound recordings by an assessor without access to the allocation list.