What is the clinical evidence from this study?

Study design: Observational. Population: Healthy volunteers (n=10). Intervention: Phase contrast MRI breath-hold techniques and image positions. Primary outcome: Stroke volume (SV).

What does this research mean for the field?

Stroke volume measurements using phase contrast MRI do not differ significantly between breath-hold methods, but stroke volume measured at the left ventricular outflow tract is significantly lower than at the ascending aorta, sino-tubular junction, and valsalva sinus. Novelty: ClaimNovelty.INCREMENTAL. Consensus alignment: ConsensusAlignment.NEUTRAL.

January 1, 2015Open Access

An Examination of Variable Image Positions in the Aortic Valve Blood Flow Using Phase Contrast MRI: Effect of Breath-holding Methods in Healthy Volunteers

Key Result

Stroke volume measurements using PC-MRI did not differ significantly between breath-hold methods, but LVOT stroke volume was significantly lower than Ao, STJ, and valsalva positions.

Study Design

Type

Observational (n=10)

Structured PICO

Does breath-holding technique or image position affect stroke volume measurement using PC-MRI in healthy volunteers?

Population

10 healthy volunteers (8 male, 2 female, age 23-33, mean age 28.1 years)

Intervention

Phase contrast MRI (PC-MRI) using different breath-holding techniques (maximum inspiration, maximum expiration, and free-breathing with navigator-echo) and image positions (ascending aorta [Ao], sino-tubular junction [STJ], valsalva sinus [valsalva], left ventricular outflow tract [LVOT])

Comparator

Comparison among the different breath-holding techniques and image positions

Outcome

Stroke volume (SV) measured at each slice position and breath-hold techniquesurrogate

In healthy volunteers, PC-MRI stroke volume measurements are not significantly affected by breath-holding methods, but measurements at the LVOT are significantly lower than at the ascending aorta, STJ, or valsalva sinus.

Abstract

Phase contrast MRI (PC-MRI) is a useful tool for evaluating valvular pathology. In addition, PC-MRI can provide a noninvasive assessment of blood flow in an arbitrary cross section. However, the blood flow measurement with breath-hold or free breath PC-MRI may be different from each other because of intrathoracic pressure changing and variable image position. The aim of this study was to find both the optimal breath-hold technique and the image position. Quantitative flow images were acquired in four planes (ascending aorta: Ao, sino-tubular junction: STJ, valsalva sinus: valsalva, left ventricular outflow tract: LVOT), in healthy subjects (n=10). The study protocol was divided into two parts: (1) stroke volume (SV) measured in each slice positions by using inspiration, expiration, and navigation method during normal breathing and (2) SV measured at each breath-hold techniques in the Ao, STJ, valsalva, and LVOT. As a result, (1) SV of the respective measurement positions were not significant by using inspiration, expiration, and navigation method and (2) LVOT SV was significantly lower than Ao, STJ, and valsalva.

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