Background Pelvimetry is essential in obstetrics for delivery planning. While computed tomography (CT) is the standard, magnetic resonance imaging (MRI) offers a radiation-free alternative with zero echo time (ZTE) and black bone (BB) sequences providing high bone-to-soft tissue contrast within short scan times. This proof-of-concept study evaluates the reliability of these sequences and the agreement with CT for pelvimetry in a predominantly elderly population. Methods This retrospective study included 21 female patients who underwent 3-T whole-body MRI including ZTE and BB sequences and 18fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/CT with optimized low-dose whole-body CT. Obstetric conjugate diameter (OCD), interspinous diameter (ISD), and median transverse diameter (MTD) were measured by five radiologists. Intra-reader, inter-reader, and inter-technique agreement were assessed using intraclass correlation coefficient (ICC) and repeatability/reproducibility coefficients. Results Intra-reader agreement was good regardless of diameter or reader: all ICC ≥ 0.90, repeatability ranging from ± 0.26 to ± 0.48 cm (CT), ± 0.30 to ± 0.52 cm (BB), and ± 0.29 to ± 0.67 cm (ZTE). The inter-reader agreement was good regardless of sequence: all ICC ≥ 0.88, reproducibility ranging from ± 0.39 to ± 0.42 (OCD), ± 0.26 to ± 0.51 cm (ISD), and ± 0.53 to ± 0.58 cm (MTD). ZTE and BB showed similar agreement with CT: ± 0.57 to ± 0.81 cm when including inter-reader variability; ± 0.34 to ± 0.47 cm for only intra-reader variability. Conclusion ZTE and BB sequences provided reliable measurements with good agreement with CT, for obstetric pelvimetry. Further validation in the context of pregnancy is needed. Relevance statement MRI-based pseudo-CT sequences are a promising radiation-free alternative to CT for obstetric pelvimetry, offering the prospect of accurate, reliable measurements of pelvic diameters in pregnant women. Trial registration The population included female patients with suspected multiple myeloma from a previous prospective oncology trial (ClinicalTrials.gov: NCT05381077). Key Points <UnorderedList Mark="Bullet"> <ItemContent> This study explores pseudo-CT MRI sequences for radiation-free non-invasive obstetric pelvimetry. </ItemContent> <ItemContent> Pseudo-CT zero echo time and black bone sequences provide repeatable and reproducible measurements of pelvic diameters. </ItemContent> <ItemContent> Pseudo-CT MRI sequences show good inter-technique agreement with the reference CT. </ItemContent> </UnorderedList> Graphical Abstract

MRI-based pseudo-CT sequences as a radiation-free alternative to CT for obstetric pelvimetry: a proof-of-concept study

期刊论文
出版模式：

开放获取
发表日期：

2025年5月19日

查看全文

Caroline Chabot,
Mathilde Haegeman,
Eya Chaouch,
Dana Dumitriu,
Renaud Menten,
Patricia Steenhaut,
Pierre Bernard,
Perrine Triqueneaux,
Nicolas Michoux,
Frédéric E. Lecouvet

摘要

Background

Pelvimetry is essential in obstetrics for delivery planning. While computed tomography (CT) is the standard, magnetic resonance imaging (MRI) offers a radiation-free alternative with zero echo time (ZTE) and black bone (BB) sequences providing high bone-to-soft tissue contrast within short scan times. This proof-of-concept study evaluates the reliability of these sequences and the agreement with CT for pelvimetry in a predominantly elderly population.

Methods

This retrospective study included 21 female patients who underwent 3-T whole-body MRI including ZTE and BB sequences and ¹⁸fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET)/CT with optimized low-dose whole-body CT. Obstetric conjugate diameter (OCD), interspinous diameter (ISD), and median transverse diameter (MTD) were measured by five radiologists. Intra-reader, inter-reader, and inter-technique agreement were assessed using intraclass correlation coefficient (ICC) and repeatability/reproducibility coefficients.

Results

Intra-reader agreement was good regardless of diameter or reader: all ICC ≥ 0.90, repeatability ranging from ± 0.26 to ± 0.48 cm (CT), ± 0.30 to ± 0.52 cm (BB), and ± 0.29 to ± 0.67 cm (ZTE). The inter-reader agreement was good regardless of sequence: all ICC ≥ 0.88, reproducibility ranging from ± 0.39 to ± 0.42 (OCD), ± 0.26 to ± 0.51 cm (ISD), and ± 0.53 to ± 0.58 cm (MTD). ZTE and BB showed similar agreement with CT: ± 0.57 to ± 0.81 cm when including inter-reader variability; ± 0.34 to ± 0.47 cm for only intra-reader variability.

Conclusion

ZTE and BB sequences provided reliable measurements with good agreement with CT, for obstetric pelvimetry. Further validation in the context of pregnancy is needed.

Relevance statement

MRI-based pseudo-CT sequences are a promising radiation-free alternative to CT for obstetric pelvimetry, offering the prospect of accurate, reliable measurements of pelvic diameters in pregnant women.

Trial registration

The population included female patients with suspected multiple myeloma from a previous prospective oncology trial (ClinicalTrials.gov: NCT05381077).

Key Points

This study explores pseudo-CT MRI sequences for radiation-free non-invasive obstetric pelvimetry.

Pseudo-CT zero echo time and black bone sequences provide repeatable and reproducible measurements of pelvic diameters.

Pseudo-CT MRI sequences show good inter-technique agreement with the reference CT.

Graphical Abstract