Systolic rise time in neurovascular duplex sonography: an important indicator of upstream vascular stenosis

Introduction

The evaluation of arterial hemodynamics plays an essential role in vascular sonography. Our essay aims to encourage the use of both visual inspection and quantification of the Doppler spectrum in transcranial and extracranial ultrasound.

Although verbal description still remains an essential part of a sonographer’s work, there are ways to objectively quantify this subjective impression. An interdisciplinary overview on the topic is provided by J. E. Trihan et al. (J Clin Med 2023; 12(3):1097).

Two routine Doppler parameters are suited for this task, especially downstream from a stenosis: One of them is the time from the start of the upslope to a defined peak, given in ms. Some authors call it peak appearance time, others (systolic) rise time or even acceleration time. Although the latter terminology is used by many, we will use “rise time” (T or Tr) in this article for clarity ([Fig. 1]). The other parameter is just called “acceleration”. It expresses the steepness of a slope and is given in m/s². As it quantifies the change of speed in a given time period, it is directly dependent on Doppler angle correction. It must be noted that there is debate as to whether “maximum acceleration” of the slope measured tangentially, as opposed to “early mean acceleration” until the first peak, should be used ([Fig. 1]).

Fig. 1 Schematic drawing of a Doppler spectrum envelope. The point of end-diastolic velocity and the first peak allow for the computation of both the early mean acceleration (solid red line with endpoints) and the systolic rise time (Tr, dotted red line with arrows). Maximum acceleration (thin blue line) is measured tangentially.

In our clinic, however, acceleration and rise time are measured using the first peak of the Doppler spectrum, if needed. With this one-step approach, the ultrasound machine computes early systolic mean acceleration and early systolic rise time at once.

Publication History

Received: 29 April 2025

Accepted after revision: 04 July 2025

Accepted Manuscript online:
04 July 2025

Article published online:
31 July 2025