Elsevier

Academic Radiology

Volume 19, Issue 8, August 2012, Pages 1011-1017
Academic Radiology

Original investigation
Thoracic and Abdominal Aortic Diameter Measurement by MRI Using Plain Axial Volumetric Interpolated Breath-hold Examination in Epidemiologic Research: A Validation Study

https://doi.org/10.1016/j.acra.2012.03.012Get rights and content

Rationale and Objectives

This study evaluates the validity and reliability of measuring the diameters of the thoracic and abdominal aorta from plain volumetric interpolated breath-hold examination (VIBE) images.

Materials and Methods

The study included 50 male subjects from the population-based Study of Health in Pomerania. They underwent imaging of the thoracic and abdominal aorta at 1.5 Tesla using a contrast-enhanced magnetic resonance angiography (CE-MRA) and plain VIBE sequence. Diameters were measured at five predefined anatomic sites from reformatted orthogonal CE-MRA images and axial plain VIBE images. The measurements were validated using Pearson correlation and Bland-Altman analysis. The Bland-Altman method was also used to assess reliability.

Results

Comparison of the diameters measured from CE-MRA and VIBE images revealed strong correlation for the ascending, descending, suprarenal, and infrarenal aorta with r = 0.95 (P < .0001), r = 0.88 (P < .0001), 0.92 (P < .0001), and 0.87 (P < .0001), respectively. Measurement for the aortic arch was moderately correlated with r = 0.78 (P < .0001). Mean bias did not exceed 0.1 cm (6%). The 95% limits of agreement (LOA) were less than 0.5 cm (15%). Intra- and interobserver agreement showed a mean bias of less than 2%; the 95% LOA were less than 11%.

Conclusions

Axial measurement of the diameters of the thoracic and abdominal aorta using a plain axial VIBE sequence is highly valid and reliable, making it suitable for use in epidemiologic research.

Section snippets

Study Population and Imaging Protocol

For the analysis imaging, data from volunteers participating in SHIP were used; patients were examined according to a standardized MRI protocol (4). In the SHIP framework, only men had the option of additionally undergoing CE-MRA. The first 53 men who underwent optional CE-MRA were consecutively included in the present analysis. They had a mean age of 54 ± 17 years (range, 21–81 years). MRI was performed at 1.5 T (Magnetom Avanto; Siemens Healthcare AG, Erlangen, Germany) using integrated coil

Results

The mean diameters of the ascending aorta, aortic arch, descending aorta, suprarenal aorta, and infrarenal aorta (calculated from the two measurements made by each observer) on CE-MRA and VIBE images were 3.39 ± 0.42 cm and 3.42 ± 0.43 cm, 2.94 ± 0.26 cm and 2.83 ± 0.28 cm, 2.75 ± 0.29 cm and 2.70 ± 0.32 cm, 2.34 ± 0.26 cm and 2.37 ± 0.28 cm, and 1.91 ± 0.16 cm and 2.03 ± 0.20, respectively.

Discussion

The measurement of aortic diameter at different anatomic levels and factors contributing to diameter variability has been investigated in numerous studies 5, 6, 8, 9, 13, 14. MRI-based studies of aortic diameter are rare. Some of the MRI studies are limited by the use of clinical images and the investigation of small populations (n < 70) 8, 9. The largest study was conducted by Wanhainen et al (5), who examined 231 70-year-old men and women using CE-MRA and measuring thoracic and abdominal

Acknowledgments

We thank our technologists for performing the magnetic resonance imaging examinations and we thank the subjects for their participation in the study.

References (21)

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Conflict of interest: None.

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