Purpose A fast T1 mapping method of the whole pancreas remains a challenge, due to the complex anatomy of the organ. In addition, a technique for pancreas water T1 mapping is needed, since the T1 is biased in the presence of fat. The purpose of this work is to accelerate the acquisition of water selective T1 (wT1) mapping for the whole pancreas at 3 T. Methods The proposed method combines a continuous inversion-recovery Look-Locker acquisition with a single-shot gradient echo spiral readout, water-fat separation and dictionary matching for wT1 mapping of the whole pancreas at 3 T. The bias of T1 in the presence of fat was evaluated in a phantom by comparing the modified Look-Locker inversion-recovery (MOLLI) and the proposed method to MRS measurements. The present method was validated in 11 volunteers by evaluating its pancreas coverage and repeatability and by comparing it to MOLLI. Four pancreatitis patients were evaluated using the proposed method and clinical scans. Results The phantom wT1 results are in better agreement to MRS (<InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10334_2025_1224_Article_IEq1.gif" Format="GIF" Height="20" Rendition="HTML" Resolution="72" Type="Linedraw" Width="286" /> </InlineMediaObject> <EquationSource Format="TEX">${\text{wT}}_{1} = 1.02{\text{wT}}_{{1{\text{MRS}}}} - 47.81,{ }R^{2} = 0.99){ }$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msub> <mtext>wT</mtext> <mn>1</mn> </msub> <mo>=</mo> <mn>1.02</mn> <msub> <mtext>wT</mtext> <mrow> <mn>1</mn> <mtext>MRS</mtext> </mrow> </msub> <mo>-</mo> <mn>47.81</mn> <mo>,</mo> <mrow /> <msup> <mi>R</mi> <mn>2</mn> </msup> <mrow> <mo>=</mo> <mn>0.99</mn> <mo stretchy="false">)</mo> <mrow /> </mrow> </mrow> </math></EquationSource> </InlineEquation> than MOLLI (<InlineEquation ID="IEq2"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10334_2025_1224_Article_IEq2.gif" Format="GIF" Height="20" Rendition="HTML" Resolution="72" Type="Linedraw" Width="321" /> </InlineMediaObject> <EquationSource Format="TEX">${\text{T}}_{{1{\text{MOLLI}}}} = 1.13{\text{wT}}_{{1{\text{MRS}}}} - 74.65, R^{2} = 0.98)$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msub> <mtext>T</mtext> <mrow> <mn>1</mn> <mtext>MOLLI</mtext> </mrow> </msub> <mo>=</mo> <mn>1.13</mn> <mrow /> <mo>∗</mo> <msub> <mtext>wT</mtext> <mrow> <mn>1</mn> <mtext>MRS</mtext> </mrow> </msub> <mo>-</mo> <mn>74.65</mn> <mo>,</mo> <msup> <mi>R</mi> <mn>2</mn> </msup> <mrow> <mo>=</mo> <mn>0.98</mn> <mo stretchy="false">)</mo> </mrow> </mrow> </math></EquationSource> </InlineEquation>. The volunteer wT1 results demonstrate the whole pancreas coverage capability for different fat fractions, good repeatability (<InlineEquation ID="IEq3"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10334_2025_1224_Article_IEq3.gif" Format="GIF" Height="21" Rendition="HTML" Resolution="72" Type="Linedraw" Width="297" /> </InlineMediaObject> <EquationSource Format="TEX">${\text{wT}}_{{1,{ }2^\circ }} = 0.98{\text{wT}}_{{1,{ }1^\circ }} + 17.40, R^{2} = 0.69)$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mmultiscripts> <mtext>wT</mtext> <mrow> <mn>1</mn> <mo>,</mo> <mrow /> <msup> <mn>2</mn> <mo>∘</mo> </msup> </mrow> <mrow /> </mmultiscripts> <mo>=</mo> <mn>0.98</mn> <mrow /> <mo>∗</mo> <mmultiscripts> <mtext>wT</mtext> <mrow> <mn>1</mn> <mo>,</mo> <mrow /> <msup> <mn>1</mn> <mo>∘</mo> </msup> </mrow> <mrow /> </mmultiscripts> <mo>+</mo> <mn>17.40</mn> <mo>,</mo> <msup> <mi>R</mi> <mn>2</mn> </msup> <mrow> <mo>=</mo> <mn>0.69</mn> <mo stretchy="false">)</mo> </mrow> </mrow> </math></EquationSource> </InlineEquation> and lower T1 values than MOLLI (<InlineEquation ID="IEq4"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10334_2025_1224_Article_IEq4.gif" Format="GIF" Height="21" Rendition="HTML" Resolution="72" Type="Linedraw" Width="298" /> </InlineMediaObject> <EquationSource Format="TEX">${\text{wT}}_{1} = 0.34{\text{T}}_{{1{\text{MOLLI}}}} + 383.65,{\text{ R}}^{2} = 0.26)$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msub> <mtext>wT</mtext> <mn>1</mn> </msub> <mo>=</mo> <mn>0.34</mn> <msub> <mtext>T</mtext> <mrow> <mn>1</mn> <mtext>MOLLI</mtext> </mrow> </msub> <mo>+</mo> <mn>383.65</mn> <mo>,</mo> <msup> <mrow> <mspace width="0.333333em" /> <mtext>R</mtext> </mrow> <mn>2</mn> </msup> <mrow> <mo>=</mo> <mn>0.26</mn> <mo stretchy="false">)</mo> </mrow> </mrow> </math></EquationSource> </InlineEquation>. The wT1 maps in patients captured diverse pancreatitis regions with higher values <InlineEquation ID="IEq5"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10334_2025_1224_Article_IEq5.gif" Format="GIF" Height="19" Rendition="HTML" Resolution="72" Type="Linedraw" Width="220" /> </InlineMediaObject> <EquationSource Format="TEX">$({\text{wT}}_{{1{\text{Patients}}}} = \left[ {831 - 1696} \right]\;{\text{ms}})$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mo stretchy="false">(</mo> <msub> <mtext>wT</mtext> <mrow> <mn>1</mn> <mtext>Patients</mtext> </mrow> </msub> <mo>=</mo> <mfenced close="]" open="["> <mrow> <mn>831</mn> <mo>-</mo> <mn>1696</mn> </mrow> </mfenced> <mspace width="0.277778em" /> <mtext>ms</mtext> <mo stretchy="false">)</mo> </mrow> </math></EquationSource> </InlineEquation> than in the volunteers <InlineEquation ID="IEq6"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10334_2025_1224_Article_IEq6.gif" Format="GIF" Height="19" Rendition="HTML" Resolution="72" Type="Linedraw" Width="224" /> </InlineMediaObject> <EquationSource Format="TEX">$\left( {{\text{wT}}_{{1{\text{Volunteers}}}} = \left[ {605 - 799} \right]\;{\text{ms}}} \right)$</EquationSource> <EquationSource Format="MATHML"><math> <mfenced close=")" open="("> <mrow> <msub> <mtext>wT</mtext> <mrow> <mn>1</mn> <mtext>Volunteers</mtext> </mrow> </msub> <mo>=</mo> <mfenced close="]" open="["> <mrow> <mn>605</mn> <mo>-</mo> <mn>799</mn> </mrow> </mfenced> <mspace width="0.277778em" /> <mtext>ms</mtext> </mrow> </mfenced> </math></EquationSource> </InlineEquation>, thus showing their potential clinical feasibility. Conclusion The present work proposes a wT1 mapping methodology of the whole pancreas at 3 T, where 24 slices (<InlineEquation ID="IEq7"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10334_2025_1224_Article_IEq7.gif" Format="GIF" Height="17" Rendition="HTML" Resolution="72" Type="Linedraw" Width="105" /> </InlineMediaObject> <EquationSource Format="TEX">$2 \times 2 \times 5\;{\text{mm}}^{3}$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mn>2</mn> <mo>×</mo> <mn>2</mn> <mo>×</mo> <mn>5</mn> <mspace width="0.277778em" /> <msup> <mrow> <mtext>mm</mtext> </mrow> <mn>3</mn> </msup> </mrow> </math></EquationSource> </InlineEquation>) were acquired in three short breath-holds of 12 s each.

Whole pancreas water T₁ mapping at 3 Tesla

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发表日期：

2025年3月6日

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Elizabeth Huaroc Moquillaza,
Kilian Weiss,
Lisa Steinhelfer,
Jonathan Stelter,
Marcus R. Makowski,
Rickmer Braren,
Mariya Doneva,
Dimitrios C. Karampinos

摘要

Purpose

A fast T₁ mapping method of the whole pancreas remains a challenge, due to the complex anatomy of the organ. In addition, a technique for pancreas water T₁ mapping is needed, since the T₁ is biased in the presence of fat. The purpose of this work is to accelerate the acquisition of water selective T₁ (wT₁) mapping for the whole pancreas at 3 T.

Methods

The proposed method combines a continuous inversion-recovery Look-Locker acquisition with a single-shot gradient echo spiral readout, water-fat separation and dictionary matching for wT₁ mapping of the whole pancreas at 3 T. The bias of T₁ in the presence of fat was evaluated in a phantom by comparing the modified Look-Locker inversion-recovery (MOLLI) and the proposed method to MRS measurements. The present method was validated in 11 volunteers by evaluating its pancreas coverage and repeatability and by comparing it to MOLLI. Four pancreatitis patients were evaluated using the proposed method and clinical scans.

Results

The phantom wT₁ results are in better agreement to MRS ( ${\text{wT}}_{1} = 1.02{\text{*wT}}_{{1{\text{MRS}}}} - 47.81,{ }R^{2} = 0.99){ }$ ${wT}_{1} = 1.02 {*wT}_{1 MRS} - 47.81, R^{2} = 0.99)$ than MOLLI ( ${\text{T}}_{{1{\text{MOLLI}}}} = 1.13*{\text{wT}}_{{1{\text{MRS}}}} - 74.65, R^{2} = 0.98)$ $T_{1 MOLLI} = 1.13 * {wT}_{1 MRS} - 74.65, R^{2} = 0.98)$ . The volunteer wT₁ results demonstrate the whole pancreas coverage capability for different fat fractions, good repeatability ( ${\text{wT}}_{{1,{ }2^\circ }} = 0.98*{\text{wT}}_{{1,{ }1^\circ }} + 17.40, R^{2} = 0.69)$ ${wT}_{1, 2^{\circ}} = 0.98 * {wT}_{1, 1^{\circ}} + 17.40, R^{2} = 0.69)$ and lower T₁ values than MOLLI ( ${\text{wT}}_{1} = 0.34{\text{*T}}_{{1{\text{MOLLI}}}} + 383.65,{\text{ R}}^{2} = 0.26)$ ${wT}_{1} = 0.34 {*T}_{1 MOLLI} + 383.65, R^{2} = 0.26)$ . The wT₁ maps in patients captured diverse pancreatitis regions with higher values $({\text{wT}}_{{1{\text{Patients}}}} = \left[ {831 - 1696} \right]\;{\text{ms}})$ $({wT}_{1 Patients} = [831 - 1696] ms)$ than in the volunteers $\left( {{\text{wT}}_{{1{\text{Volunteers}}}} = \left[ {605 - 799} \right]\;{\text{ms}}} \right)$ $({wT}_{1 Volunteers} = [605 - 799] ms)$ , thus showing their potential clinical feasibility.

Conclusion

The present work proposes a wT₁ mapping methodology of the whole pancreas at 3 T, where 24 slices ( $2 \times 2 \times 5\;{\text{mm}}^{3}$ $2 \times 2 \times 5 {mm}^{3}$ ) were acquired in three short breath-holds of 12 s each.

Whole pancreas water T1 mapping at 3 Tesla

摘要

Whole pancreas water T₁ mapping at 3 Tesla