2024年6月17日发(作者：)

timing bolus technique, 中文术语

Timing bolus technique is a crucial concept in the field of medical

imaging, specifically in computed tomography (CT) angiography.

This technique plays a significant role in obtaining high-quality

images of blood vessels by precisely timing the injection of

contrast media. In this article, we will delve into the intricacies of

the timing bolus technique, its purpose, process, and its relevance

in clinical practice.

Timing bolus technique, in Chinese known as "定时对比剂技术," is

designed to optimize the timing of a contrast medium injection

during CT angiography. The ultimate goal is to achieve maximum

enhancement of the blood vessels while minimizing artifacts

caused by contrast media dispersion or washout. By accurately

timing the contrast medium injection, radiologists can obtain

precise images that accurately depict the vascular structures.

The timing bolus technique involves several steps. The first step is

patient preparation, which includes ensuring the patient's medical

history is thoroughly reviewed, which can help the radiologist

identify any potential contraindications or risks. It also involves

verifying the patient's renal function to determine the appropriate

contrast medium and dosage.

The second step is the setup phase. During this phase, the CT

scanner is properly calibrated, and the appropriate scan parameters

are selected. The positioning of the patient is also crucial, as it

affects the accuracy of the scan. The patient is typically positioned

supine on the CT table, and the area of interest is localized.

The third step is the actual timing bolus process. Firstly, a small test

injection of contrast media, commonly iodinated contrast agents, is

administered to determine the individual patient's circulation time.

This test injection is referred to as the timing bolus. The timing

bolus is typically administered via a peripheral intravenous line,

usually in the antecubital fossa of the arm.

The timing bolus is monitored using a region of interest (ROI)

placed within an artery or vein near the area of interest. The ROI

measures the contrast media's arrival time and peak intensity. This

information is essential in calculating the optimal scan delay for

subsequent CT angiography.

Various monitoring techniques are employed during the timing

bolus phase. These include monitoring the contrast injection using

an injector pump, real-time monitoring of Hounsfield unit (HU)

within the ROI, and obtaining test scans to detect the precise

timing of the contrast media's arrival. These monitoring techniques

collectively aid in determining the peak enhancement time.

Once the timing bolus has been administered and appropriately

monitored, the fourth step involves adjusting the scanning delay.

This delay is crucial to ensure that the contrast media reaches its

peak intensity within the area of interest. The delay is usually

calculated based on the circulation time determined during the

timing bolus stage, taking into account the patient's body weight

and other relevant factors.

Finally, the fifth step is the acquisition of the actual CT angiography

scan. The CT scanner is programmed to start the scanning process

at the predetermined delay time calculated during the previous

step. The images are acquired in a rapid sequence, allowing the

radiologist to capture the arterial and venous phases required for a

comprehensive evaluation of the vascular structures.

The timing bolus technique is of paramount importance in clinical

practice. It allows radiologists to obtain optimal imaging results by

ensuring that the contrast media reaches its peak intensity at the

precise moment when the CT scanner captures the images. This

technique helps minimize artifacts and blurring caused by contrast

dispersion or washout, improving the overall quality and diagnostic

value of CT angiography.

Moreover, the timing bolus technique enables accurate

visualization and evaluation of blood vessels, aiding in the

diagnosis and treatment planning of various vascular diseases. It is

particularly valuable in diagnosing conditions such as aneurysms,

arterial stenosis, or venous thrombosis.

In conclusion, the timing bolus technique plays a vital role in CT

angiography, optimizing the timing of the contrast media injection

and enhancing the quality of vascular imaging. Through careful

patient preparation, monitoring, and precise timing adjustments,

radiologists can achieve accurate and high-quality images. This

technique is widely employed in clinical practice and significantly

contributes to the diagnosis and management of vascular diseases.