What is the clinical evidence from this study?

Study design: Observational. Intervention: 7T cardiac MRI with B1 shimming vs. 3T cardiac MRI. Primary outcome: Volumetric and strain parameters.

What question did this study set out to answer?

The aim is to develop an efficient B1 shimming workflow for cine imaging at 7T and assess its effects on cardiac parameters.

June 17, 2026Open Access

Cardiac function and myocardial strain analysis at 7T using B1 shimming in comparison to 3T magnetic resonance imaging.

Key Result

Cardiac MRI at 7T using a single B1 shim set slightly underestimated left ventricular volumes (<10% difference) compared to 3T, but did not impact strain parameters or diagnostic quality.

Key Points

The aim is to develop an efficient B1 shimming workflow for cine imaging at 7T and assess its effects on cardiac parameters.
Ten volunteers underwent cardiac MRI scans at both 3T and 7T.
A single B1 shim set was applied during the imaging sessions to mitigate signal variation.
Biventricular volumetric parameters and peak strain were analyzed using feature tracking.
At 7T, left ventricular volumes were slightly underestimated (differences <10%), deemed clinically minimal.
Strain parameters were unaffected by field strength changes.
Image quality at 7T was inferior to 3T, yet all images were considered diagnostically usable.

Study Design

Type

Observational (n=10)

Structured PICO

Does cardiac MRI at 7T using a single B1 shim set provide comparable image quality, volumetric, and strain parameters to 3T MRI in volunteers?

Population

10 volunteers undergoing cardiac MRI at 3T and 7T for comparison of volumetric and strain parameters.

Exposure

Cardiac MRI at 7T using a single B1 shim set for cine imaging

Comparator

Cardiac MRI at 3T

Outcome

Image quality, biventricular volumetric parameters, and peak strainsurrogate

An efficient workflow using a single B1 shim set for cardiac cine imaging at 7T provides diagnostically usable images and comparable strain analysis to 3T, despite slight underestimation of LV volumes.

Abstract

Due to spatial heterogeneities of transmit B1 magnitude, cardiac MRI at 7 Tesla is still far from being clinically established. Different strategies were proposed to mitigate signal variations that may lead to a significant increase of the examination time. The aim of this study was to establish an efficient workflow for B1 shimming for cine imaging at 7T with a single B1 shim set and the investigation of the impact of field strength on volumetric and strain parameters Long- and short-axis images were acquired in ten volunteers at 3T and 7T. At 7T, B1 maps were acquired to calculate a single B1 phases him vector that was applied for the entire exam. Image quality reading was performed by two radiologists. Biventricular volumetric parameters were assessed by two readers. Biventricular function was further assessed for peak strain using feature tracking Image quality and contrast of long-axis images acquired at 7T was inferior compared to 3T, although all images were deemed to bediagnostically usable. In comparison to 3T, 7T slightly underestimated left ventricular volumes, with differences remaining under 10%of absolute values and thus of minimal clinical relevance. Strain parameters were not impacted by field strength A single B1 shim set provides excitation patterns without substantial signal dropouts in the heart. Moderate residual B1 variations and the reduced myocardium-blood contrast at 7T hindered neither quantification nor diagnostic quality. In conclusion, an efficient workflow could be realized at 7T for cardiac cine imaging for function and strain analysis.