From 09e4d3559f9a714dd36981b041927bc6ef944aa8 Mon Sep 17 00:00:00 2001
From: Michiel Cottaar <michiel.cottaar@ndcn.ox.ac.uk>
Date: Tue, 20 Feb 2024 13:42:42 +0000
Subject: [PATCH] Count EPI as single readout
---
src/parts/epi_readouts.jl | 23 ++++++++++++++++++++++-
1 file changed, 22 insertions(+), 1 deletion(-)
diff --git a/src/parts/epi_readouts.jl b/src/parts/epi_readouts.jl
index 7f1e6b6..9549c32 100644
--- a/src/parts/epi_readouts.jl
+++ b/src/parts/epi_readouts.jl
@@ -2,7 +2,8 @@ module EPIReadouts
import ...Containers: BaseSequence, get_index_single_TR
import ..Trapezoids: Trapezoid, opposite_kspace_lines, LineReadout
import ...Components: ADC
-import ...Variables: get_free_variable, VariableType, qval, qvec, set_simple_constraints!, resolution, inverse_voxel_size, inverse_fov, resolution, get_readout, apply_simple_constraint!
+import ...Variables: get_free_variable, VariableType, qval, qvec, set_simple_constraints!, resolution, inverse_voxel_size, inverse_fov, resolution, get_readout, apply_simple_constraint!, effective_time
+import ...Pathways: PathwayWalker, update_walker_till_time!
"""
EPIReadout(resolution; ky_lines=-resolution[2]:resolution[2], recenter=false, group=:FOV, variables...)
@@ -64,6 +65,13 @@ inverse_fov(epi::EPIReadout) = [inverse_fov(epi.positive_line), 1e3 * epi.ky_ste
inverse_voxel_size(epi::EPIReadout) = [inverse_voxel_size(epi.positive_line), 1e3 * epi.ky_step * maximum(abs.(epi.ky_lines))]
resolution(epi::EPIReadout) = [resolution(epi.positive_line), maximum(abs.(epi.ky_lines))]
get_readout(epi::EPIReadout) = epi.positive_line
+function effective_time(epi::EPIReadout)
+ index = findfirst(iszero, epi.ky_lines)
+ if isnothing(index)
+ error("EPI readout does not pass through the centre of k-space")
+ end
+ return effective_time(epi, index * 2)
+end
function get_index_single_TR(epi::EPIReadout, index::Integer)
if index == 1
@@ -84,4 +92,17 @@ function get_index_single_TR(epi::EPIReadout, index::Integer)
end
end
+# overrides default pathway behaviour, so that EPI is counted as a single readout
+function walk_pathway!(epi::EPIReadout, walker::PathwayWalker, pulse_effects::Vector{Symbol}, nreadout::Ref{Int}, block_start_time::VariableType)
+ if length(pulse_effects) > 0
+ return false
+ end
+ nreadout[] -= 1
+ if nreadout[] > 0
+ return false
+ end
+ update_walker_till_time!(walker, block_start_time + effective_time(epi))
+ return true
+end
+
end
\ No newline at end of file
--
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