From b359ad71f3e26e9c27e604451edc36b2a60c99c8 Mon Sep 17 00:00:00 2001 From: Mathieu Boudreau Date: Tue, 8 Oct 2024 10:35:03 -0300 Subject: [PATCH] Partial inline b0 --- 5 B0 Mapping/3 Phase Unwrapping/02-Temporal Unwrapping.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/5 B0 Mapping/3 Phase Unwrapping/02-Temporal Unwrapping.md b/5 B0 Mapping/3 Phase Unwrapping/02-Temporal Unwrapping.md index 8d301e9..46fd05b 100644 --- a/5 B0 Mapping/3 Phase Unwrapping/02-Temporal Unwrapping.md +++ b/5 B0 Mapping/3 Phase Unwrapping/02-Temporal Unwrapping.md @@ -27,7 +27,7 @@ Temporal unwrapping uses multiple time points (>=2) to unwrap the image. By acqu ``` -If we assume a maximum field offset {math}`\Delta f_{0,max}` of 1 ppm at 3T (~127 MHz), we can calculate a maximum field offset ({math}`\Delta f_{0,max}`) of 1 µT or 127 Hz. The [Nyquist criteria](https://en.wikipedia.org/wiki/Nyquist_frequency) can be used to calculate the maximum echo time difference (TE) required to satisfy the no-wrapping requirement in the phase difference image ({math}`\Delta \text{TE} = \left( \Delta f_{0,max} \right)^{-1}). Table 1 shows TE for multiple field strength assuming inhomogeneities of 1 ppm. As shown, the echo spacing is _B_{sub}`0` dependent, as higher field offsets are observed at higher field strengths. +If we assume a maximum field offset {math}`\Delta f_{0,max}` of 1 ppm at 3T (~127 MHz), we can calculate a maximum field offset ({math}`\Delta f_{0,max}`) of 1 µT or 127 Hz. The [Nyquist criteria](https://en.wikipedia.org/wiki/Nyquist_frequency) can be used to calculate the maximum echo time difference (TE) required to satisfy the no-wrapping requirement in the phase difference image ({math}`\Delta \text{TE} = \left( \Delta f_{0,max} \right)^{-1}`). Table 1 shows TE for multiple field strength assuming inhomogeneities of 1 ppm. As shown, the echo spacing is _B_{sub}`0` dependent, as higher field offsets are observed at higher field strengths. ```{list-table} Maximum echo time required to respect the Nyquist criteria for different field strengths for ΔB0 of 1 ppm. :header-rows: 1