Aortic structure — CMR phenotype documentation

Aorta

The aorta is the largest elastic artery in the human body is classically divided into two anatomical segments, the thoracic aorta and the abdominal aorta, separated by the diaphragm. The thoracic aorta presents higher compliance as compared to the abdominal aorta and its elastic capacity, especially in the proximal segments, actively contributes to maintaining diastolic pressure and blood flow at the level of peripheral circulation (Di Gioia et al. 2023).

The thoracic aorta includes the aortic root, the ascending aorta, the arch, and the descending aorta. The ascending aorta comprises the tract from the STJ to approximately the level of the fourth thoracic vertebra, where the brachiocephalic artery takes off. The aortic arch lies between the brachiocephalic artery and the isthmus, distal to the left subclavian artery origin, and gives rise to the brachiocephalic, the left common carotid, and the left subclavian arteries. The descending aorta starts after the take-off of the left subclavian artery and has a thoracic and abdominal segment (Di Gioia et al. 2023).

<figure> <img src="/latex/images/aorta/aorta_structure1.png" id="fig:aorta1" alt="Diagram of the aorta, with color-coded anatomical segmentation (Di Gioia et al. 2023)." /><figcaption aria-hidden="true">Diagram of the aorta, with color-coded anatomical segmentation <span>(Di Gioia et al. 2023)</span>.</figcaption> </figure>

Diameter

The anatomy of the aortic arch is challenging to assess due to its angulated configuration and the presence of supra-aortic branches. Aortic diameters can be measured in the ascending and descending aorta, as well as in the supra-aortic trunks, including the innominate artery (IA), left common carotid artery (LCCA), and left subclavian artery (LSCA). A detailed list of measures of aortic arch and supra-aortic trunks determined using the protocol or manually can be found in (Girsowicz et al. 2017).

<figure> <img src="/latex/images/aorta/aorta_structure2.png" id="fig:aorta2" alt="Diagram illustrating the measurements of the different morphometric and geometric parameters: Point Z_0 at the level of the pulmonary trunk bifurcation; point Z_1 at the distal edge of innominate artery; point Z_2 at the distal edge of left common carotid artery and point Z_3 at the distal edge of the left subclavian artery; aortic diameters of zone 0 (D_0), zone 1 (D_1), zone 2 (D_2), zone 3 (D_3) (Boufi et al. 2017)." /><figcaption aria-hidden="true">Diagram illustrating the measurements of the different morphometric and geometric parameters: Point <span class="math inline"><em>Z</em><sub>0</sub></span> at the level of the pulmonary trunk bifurcation; point <span class="math inline"><em>Z</em><sub>1</sub></span> at the distal edge of innominate artery; point <span class="math inline"><em>Z</em><sub>2</sub></span> at the distal edge of left common carotid artery and point <span class="math inline"><em>Z</em><sub>3</sub></span> at the distal edge of the left subclavian artery; aortic diameters of zone 0 (<span class="math inline"><em>D</em><sub>0</sub></span>), zone 1 (<span class="math inline"><em>D</em><sub>1</sub></span>), zone 2 (<span class="math inline"><em>D</em><sub>2</sub></span>), zone 3 (<span class="math inline"><em>D</em><sub>3</sub></span>) <span>(Boufi et al. 2017)</span>.</figcaption> </figure>

Definition: Diameters of aorta measured at a specific location, or averaged across a specific region.
Acquisition Type: Thoracic scout MRI, Aortic distensibility cine

Reference Range:

Mean across aorta:
Study Cohort Size Reference Value (mm) Note
(Kurugol et al. 2015) 2500 (26.2, 2.6) 46% males, 54 % females, average age 59.76 years, COPDGene study

Study	Cohort Size	Reference Value (mm)	Note
(Kurugol et al. 2015)	2500	(26.2, 2.6)	46% males, 54 % females, average age 59.76 years, COPDGene study

Mean across ascending aorta:

Study	Cohort Size	Gender	Age	Reference Value (mm)	Note
(Kurugol et al. 2015)	2500			(30.8, 3.4)	46% males, 54 % females, average age 59.76 years, COPDGene study
(Obel et al. 2021)	14989			(37.3, 4.1)	14235 males, 754 females, average age 67.8 years, DANCAVAS I and II study
(Wolak et al. 2008)	2510			(34.0, 4.1)	average age 53.5 years
	1529			(31.8, 3.17)	average age 57.5 years
(Redheuil et al. 2011)	45	male		(31, 4)	average age 45 years
	55	female		(30, 4)	average age 48 years
(Turkbey et al. 2014)	345	male	45-54	27.2-37.3
	229	male	55-64	28.1-40.7
	139	male	65-74	28.7-41.0
	57	male	75-84	28.6-40.8
	416	male	45-54	24.6-34.4
	232	female	55-64	25.7-36.4
	157	female	65-74	26.1-36.3
	37	female	75-84	26.8-37.1
(Davis et al. 2014)	208	male		18.7-33.3	average age 36 years
	239	female		17.8-31.6	average age 38 years
(Boufi et al. 2017)	123			(30, 0.71)	73 males, 50 females, average age 53 years
(Qiu et al. 2020)	534			(32.9, 4.1)	312 males, 222 females, average age 65.24 years

Mean across aortic arch:

Study	Cohort Size	Reference Value (mm)	Note
(Kurugol et al. 2015)	2500	(27.6, 2.6)	46% males, 54 % females, average age 59.76 years, COPDGene study
(Obel et al. 2021)	14989	(30.6, 3.0)	14235 males, 754 females, average age 67.8 years, DANCAVAS I and II study
(Qiu et al. 2020)	534	(25.6, 3.4)	312 males, 222 females, average age 65.24 years

Mean across proximal descending aorta:

Study	Cohort Size	Gender	Age	Reference Value (mm)	Note
(Kurugol et al. 2015)	2500			(23.6, 2.6)	46% males, 54 % females, average age 59.76 years, COPDGene study
(Obel et al. 2021)	14989			(28.3, 2.8)	14235 males, 754 females, average age 67.8 years, DANCAVAS I and II study
(Redheuil et al. 2011)	45	male		(24, 3)	average age 45 years
	55	female		(22, 3)	average age 48 years
(Eikendal et al. 2016)	19	male	25-30	19.49-24.13	total vessel diameter
	19	male	25-30	16.20-21.30	lumen diameter
	40	male	30-35	19.97-24.19	total vessel diameter
	40	male	30-35	16.65-21.09	lumen diameter
	28	female	25-30	18.66-21.14	total vessel diameter
	28	female	25-30	15.58-18.21	lumen diameter
	37	female	30-35	19.31-22.89	total vessel diameter
	37	female	30-35	15.93-19.63	lumen diameter
(Davis et al. 2014)	208	male		14.7-25.5	average age 36 years
	239	female		14.6-22.4	average age 38 years
(Qiu et al. 2020)	534			(24.1, 3.6)	312 males, 222 females, average age 65.24 years

Innominate artery (distal edge):
Study Cohort Size Reference Value (mm) Note
(Boufi et al. 2017) 123 (28, 0.71) 73 males, 50 females, average age 53 years
(Sun et al. 2021) 168 (29.5, 3.2) 137 males, 31 females, average age 56.5 years
Left common carotid artery (distal edge):
Study Cohort Size Reference Value (mm) Note
(Boufi et al. 2017) 123 (26, 0.71) 73 males, 50 females, average age 53 years
(Sun et al. 2021) 168 (26.3, 2.4) 137 males, 31 females, average age 56.5 years
Left subclavian artery (distal edge):
Study Cohort Size Reference Value (mm) Note
(Boufi et al. 2017) 123 (25, 0.53) 73 males, 50 females, average age 53 years
(Sun et al. 2021) 168 (25.1, 2.6) 137 males, 31 females, average age 56.5 years

Clinical Associations:
The diameters of the ascending aorta, aortic arch, and total proximal aorta are significantly larger in patients with Type B aortic dissection (TBAD) compared to controls (Cao et al. 2020). The ascending aorta diameter is also larger in patients with BAV (Philip et al. 2015). Additionally, aortic dissection and rupture are frequently associated with increased aortic diameter (Erbel 2006). There is a significant trend, independent of age, towards larger BSA-indexed ascending aortic diameters with increasing valve fusion in females with Turner syndrome (TS)(Olivieri et al. 2013). Primary aortic dilation is also associated with coarctation of the aorta (CoA), BAV, and conotruncal anomalies such as tetralogy of Fallot (TOF) and pulmonary atresia (PA) with ventricular septal defect (VSD) (Francois 2015). In contrast, aortic arch diameters are smaller in patients with coarctation than in healthy individuals (Minderhoud et al. 2024).

Study	Cohort Size	Reference Value (mm)	Note
(Boufi et al. 2017)	123	(28, 0.71)	73 males, 50 females, average age 53 years
(Sun et al. 2021)	168	(29.5, 3.2)	137 males, 31 females, average age 56.5 years

Study	Cohort Size	Reference Value (mm)	Note
(Boufi et al. 2017)	123	(26, 0.71)	73 males, 50 females, average age 53 years
(Sun et al. 2021)	168	(26.3, 2.4)	137 males, 31 females, average age 56.5 years

Study	Cohort Size	Reference Value (mm)	Note
(Boufi et al. 2017)	123	(25, 0.53)	73 males, 50 females, average age 53 years
(Sun et al. 2021)	168	(25.1, 2.6)	137 males, 31 females, average age 56.5 years

(Cross-sectional) Area

Definition: The cross-sectional area of aorta in a plane orthogonal to the vessel centerline.
Acquisition Type: Thoracic scout MRI, Aortic distensibility cine, PC

Reference Range:

Ascending aorta, maximal

Study	Cohort Size	Reference Value (cm<sup>2</sup>)	Note
(Assadi et al. 2023)	169	(6.7, 2.3)	96 males, 73 females
(Mehmood et al. 2024)	10	(7.0, 2.0)	9 males, 1 female, average age 22.9 years
	10	(9.0, 3.0)	4 males, 6 females, average age 60.5 years
(Zhao et al. 2023)	58	(6.1, 1.0)	35 males, 23 females, age ranges: 21-36 years
	56	(7.1, 1.5)	30 males, 26 females, age ranges: 37-50 years
	55	(8.3, 1.7)	31 males, 24 females, age ranges: 51-76 years

Ascending aorta, minimal

Study	Cohort Size	Reference Value (cm<sup>2</sup>)	Note
(Assadi et al. 2023)	169	(5.3, 2.0)	96 males, 73 females
(Mehmood et al. 2024)	10	(5.0, 1.0)	9 males, 1 female, average age 22.9 years
	10	(7.0, 2.0)	4 males, 6 females, average age 60.5 years
(Zhao et al. 2023)	58	(4.6, 1.0)	35 males, 23 females, age ranges: 21-36 years
	56	(5.5, 1.2)	30 males, 26 females, age ranges: 37-50 years
	55	(7.0, 1.7)	31 males, 24 females, age ranges: 51-76 years

Descending aorta

Study	Cohort Size	Reference Value (cm<sup>2</sup>)	Note
(Eikendal et al. 2016)	19	male	25-30	3.00-4.65	total vessel area
	19	male	25-30	2.05-3.59	lumen area
	40	male	30-35	3.13-4.62	total vessel area
	40	male	30-35	2.23-3.52	lumen area
	28	female	25-30	2.75-3.51	total vessel area
	28	female	25-30	1.91-2.59	lumen area
	37	female	30-35	2.93-4.15	total vessel area
	37	female	30-35	2.01-3.05	lumen area

Clinical Associations: The cross-sectional areas of the ascending and descending aorta are larger in patients with BAV (Singh et al. 2019).

Length

Two segmentation conventions are commonly used to delineate the thoracic aorta in imaging-based analyses. The first is an anatomical segmentation, in which the ascending aorta, aortic arch, and descending aorta are defined according to the origins of the major supra-aortic branches, namely the innominate (brachiocephalic) artery, the left common carotid artery, and the left subclavian artery. This approach follows standard anatomical landmarks (Cao et al. 2020; Qiu et al. 2020; Sun et al. 2021).

The second is a geometric, centerline-based segmentation, in which the aortic arch is defined according to the curvature profile of the vessel centerline. Specifically, the arch corresponds to the superior portion of the centerline bounded by the inflection point of curvature, or by the midpoint between the ascending and descending limbs of the aortic trajectory. This method provides a continuous and reproducible description of the aortic geometry, independent of the branching anatomy (Redheuil et al. 2011; Beeche et al. 2024).

<figure> <img src="/latex/images/aorta/aorta_structure4.png" id="fig:aorta3" style="width:70.0%" alt="Diagram illustrating the measurements of the different morphometric and geometric parameters: Point Z_0 at the level of the pulmonary trunk bifurcation; point Z_1 at the distal edge of innominate artery; point Z_2 at the distal edge of left common carotid artery; point Z_3 at the distal edge of the left subclavian artery and point Z_4 at the level of the fourth thoracic vertebra body under edge; lengths L_0,L_1,L_2 and L_3 of the different zones (Boufi et al. 2017)." /><figcaption aria-hidden="true">Diagram illustrating the measurements of the different morphometric and geometric parameters: Point <span class="math inline"><em>Z</em><sub>0</sub></span> at the level of the pulmonary trunk bifurcation; point <span class="math inline"><em>Z</em><sub>1</sub></span> at the distal edge of innominate artery; point <span class="math inline"><em>Z</em><sub>2</sub></span> at the distal edge of left common carotid artery; point <span class="math inline"><em>Z</em><sub>3</sub></span> at the distal edge of the left subclavian artery and point <span class="math inline"><em>Z</em><sub>4</sub></span> at the level of the fourth thoracic vertebra body under edge; lengths <span class="math inline"><em>L</em><sub>0</sub>, <em>L</em><sub>1</sub>, <em>L</em><sub>2</sub></span> and <span class="math inline"><em>L</em><sub>3</sub></span> of the different zones <span>(Boufi et al. 2017)</span>.</figcaption> </figure>

<figure> <img src="/latex/images/aorta/aorta_structure3.png" id="fig:aorta3" alt="Diagram illustrating the measurements of the different morphometric and geometric parameters: Point Z_0 at the level of the pulmonary trunk bifurcation; point Z_1 at the distal edge of innominate artery; point Z_2 at the distal edge of left common carotid artery; point Z_3 at the distal edge of the left subclavian artery and point Z_4 at the level of the fourth thoracic vertebra body under edge; lengths L_0,L_1,L_2 and L_3 of the different zones (Boufi et al. 2017)." /><figcaption aria-hidden="true">Diagram illustrating the measurements of the different morphometric and geometric parameters: Point <span class="math inline"><em>Z</em><sub>0</sub></span> at the level of the pulmonary trunk bifurcation; point <span class="math inline"><em>Z</em><sub>1</sub></span> at the distal edge of innominate artery; point <span class="math inline"><em>Z</em><sub>2</sub></span> at the distal edge of left common carotid artery; point <span class="math inline"><em>Z</em><sub>3</sub></span> at the distal edge of the left subclavian artery and point <span class="math inline"><em>Z</em><sub>4</sub></span> at the level of the fourth thoracic vertebra body under edge; lengths <span class="math inline"><em>L</em><sub>0</sub>, <em>L</em><sub>1</sub>, <em>L</em><sub>2</sub></span> and <span class="math inline"><em>L</em><sub>3</sub></span> of the different zones <span>(Boufi et al. 2017)</span>.</figcaption> </figure>

Definition: The centerline distance of the aortic segment.
Acquisition Type: Thoracic scout MRI
Reference Range:
1. Ascending aorta according to the anatomical segmentation:
  Study Cohort Size Reference Value (mm) Note
  (Qiu et al. 2020) 534 (61.80, 11.09) 312 males, 222 females, average age 65.24 years
  (Sun et al. 2021) 168 (66.8, 8.2) 137 males, 31 females, average age 56.5 years
2. Aortic arch according to the geometric segmentation:
  Study Cohort Size Gender Reference Value (mm) Note
  (Redheuil et al. 2011) 45 male (122, 21) average age 45 years
  55 female (110, 15) average age 48 years
3. Aortic arch according to the anatomical segmentation:
  Study Cohort Size Reference Value (mm) Note
  (Qiu et al. 2020) 534 (25.54, 7.47) 312 males, 222 females, average age 65.24 years
  (Sun et al. 2021) 168 (38.1, 7.6) 137 males, 31 females, average age 56.5 years
4. Proximal descending aorta according to the anatomical segmentation:
  Study Cohort Size Reference Value (mm) Note
  (Qiu et al. 2020) 534 (68.14, 15.67) 312 males, 222 females, average age 65.24 years
5. Distal descending aorta according to the geometric segmentation:
  Study Cohort Size Gender Reference Value (mm) Note
  (Redheuil et al. 2011) 45 male (143, 15) average age 45 years
  55 female (134, 16) average age 48 years
6. Distal descending aorta according to the anatomical segmentation:
  Study Cohort Size Reference Value (mm) Note
  (Qiu et al. 2020) 534 (152.05, 23.44) 312 males, 222 females, average age 65.24 years
7. From pulmonary trunk bifurcation to the distal edge of innominate artery:
  Study Cohort Size Reference Value (mm) Note
  (Boufi et al. 2017) 123 (30, 0.71) 73 males, 50 females, average age 53 years
8. From the distal edge of innominate artery to the distal edge of left common carotid artery:
  Study Cohort Size Reference Value (mm) Note
  (Boufi et al. 2017) 123 (28, 0.71) 73 males, 50 females, average age 53 years
9. From the distal edge of left common carotid artery to distal edge of the left subclavian artery:
  Study Cohort Size Reference Value (mm) Note
  (Boufi et al. 2017) 123 (26, 0.71) 73 males, 50 females, average age 53 years
10. From the distal edge of left subclavian artery to the level of the fourth thoracic vertebra body under edge:
  Study Cohort Size Reference Value (mm) Note
  (Boufi et al. 2017) 123 (25, 0.53) 73 males, 50 females, average age 53 years
Clinical Associations: The length of total aorta, as well as the ascending aorta and aortic arch are elongated in the acute TBAD group (Qiu et al. 2020; Sun et al. 2021).

Study	Cohort Size	Reference Value (mm)	Note
(Qiu et al. 2020)	534	(61.80, 11.09)	312 males, 222 females, average age 65.24 years
(Sun et al. 2021)	168	(66.8, 8.2)	137 males, 31 females, average age 56.5 years

Study	Cohort Size	Gender	Reference Value (mm)	Note
(Redheuil et al. 2011)	45	male	(122, 21)	average age 45 years
	55	female	(110, 15)	average age 48 years

Study	Cohort Size	Reference Value (mm)	Note
(Qiu et al. 2020)	534	(25.54, 7.47)	312 males, 222 females, average age 65.24 years
(Sun et al. 2021)	168	(38.1, 7.6)	137 males, 31 females, average age 56.5 years

Study	Cohort Size	Reference Value (mm)	Note
(Qiu et al. 2020)	534	(68.14, 15.67)	312 males, 222 females, average age 65.24 years

Study	Cohort Size	Gender	Reference Value (mm)	Note
(Redheuil et al. 2011)	45	male	(143, 15)	average age 45 years
	55	female	(134, 16)	average age 48 years

Study	Cohort Size	Reference Value (mm)	Note
(Qiu et al. 2020)	534	(152.05, 23.44)	312 males, 222 females, average age 65.24 years

Study	Cohort Size	Reference Value (mm)	Note
(Boufi et al. 2017)	123	(30, 0.71)	73 males, 50 females, average age 53 years

Study	Cohort Size	Reference Value (mm)	Note
(Boufi et al. 2017)	123	(28, 0.71)	73 males, 50 females, average age 53 years

Study	Cohort Size	Reference Value (mm)	Note
(Boufi et al. 2017)	123	(26, 0.71)	73 males, 50 females, average age 53 years

Study	Cohort Size	Reference Value (mm)	Note
(Boufi et al. 2017)	123	(25, 0.53)	73 males, 50 females, average age 53 years

Arch Width

In order to measure the aortic arch height and width, a triangle can be drawn between the arch apex and the midline of the ascending and descending aorta at the level of the right pulmonary artery. Arch width is the length of the base of the triangle. Arch height is the vertical distance between the pulmonary artery and the arch vertex (Alhafez et al. 2019).

<figure> <img src="/latex/images/aorta/aorta_arch1.png" id="fig:aorta_arch2" alt="Diagram illustrating aortic arch measurements, including arch height, width, as well as aortic diameters at the sinuses of Valsalva, sinotubular junction (Alhafez et al. 2019). Definition 2 of arch height is determined based on the segmentation criteria shown in the diagram." /><figcaption aria-hidden="true">Diagram illustrating aortic arch measurements, including arch height, width, as well as aortic diameters at the sinuses of Valsalva, sinotubular junction <span>(Alhafez et al. 2019)</span>. Definition 2 of arch height is determined based on the segmentation criteria shown in the diagram.</figcaption> </figure>

<figure> <img src="/latex/images/aorta/aorta_arch2.png" id="fig:aorta_arch2" alt="Diagram illustrating aortic arch measurements, including arch height, width, as well as aortic diameters at the sinuses of Valsalva, sinotubular junction (Alhafez et al. 2019). Definition 2 of arch height is determined based on the segmentation criteria shown in the diagram." /><figcaption aria-hidden="true">Diagram illustrating aortic arch measurements, including arch height, width, as well as aortic diameters at the sinuses of Valsalva, sinotubular junction <span>(Alhafez et al. 2019)</span>. Definition 2 of arch height is determined based on the segmentation criteria shown in the diagram.</figcaption> </figure>

Definition: The maximum distance between the outer curvature of the ascending aorta and descending aorta (Qiu et al. 2020).
Acquisition Type: Thoracic scout MRI

Reference Range:

Study	Cohort Size	Gender	Reference Value (mm)	Note
(Redheuil et al. 2011)	45	male	(72, 11)	average age 45 years
	55	female	(66, 10)	average age 48 years
(Alhafez et al. 2019)	234		73-91	155 males, 79 females, average age 54 years
(Qiu et al. 2020)	534		(72.05, 14.04)	312 males, 222 females, average age 65.24 years

Clinical Associations: The aortic width is elevated in patients with TBAD (Qiu et al. 2020).

Arch Height

Definition 1: The vertical distance between the origin of the brachiocephalic artery and the arch vertex (Qiu et al. 2020).
Definition 2: The length of the orthogonal projection of the centerline curve’s inflection point at the top of the aortic arch on the width of the aortic arch (Redheuil et al. 2011).
Acquisition Type: Thoracic scout MRI
Reference Range:
1. Measured according to definition 1:
  Study Cohort Size Gender Reference Value (mm) Note
  (Redheuil et al. 2011) 45 male (40, 7) average age 45 years
  55 female (37, 6) average age 48 years
2. Measured according to definition 2:
  Study Cohort Size Reference Value (mm) Note
  (Qiu et al. 2020) 534 (18.53, 8.94) 312 males, 222 females, average age 65.24 years
Clinical Associations: The aortic height is elevated in patients with TBAD (Qiu et al. 2020). For patients with bicuspid aortic valve (BAV), they show increased arch height, but no significant difference in arch width compared to tricuspid aortic valve (TAV) controls (Alhafez et al. 2019).

Study	Cohort Size	Gender	Reference Value (mm)	Note
(Redheuil et al. 2011)	45	male	(40, 7)	average age 45 years
	55	female	(37, 6)	average age 48 years

Study	Cohort Size	Reference Value (mm)	Note
(Qiu et al. 2020)	534	(18.53, 8.94)	312 males, 222 females, average age 65.24 years

Curvature

Once the centerline of the aorta is determined, based on this centerline, the curvature, torsion and tortuosity of the centerline can be determined for a more comprehensive analysis of the aortic morphology (Minderhoud et al. 2024).

<figure> <img src="/latex/images/aorta/aorta_geometry.png" id="fig:aorta_geometry" alt="Extraction of geometrical features of segmented aortas (Minderhoud et al. 2024)." /><figcaption aria-hidden="true">Extraction of geometrical features of segmented aortas <span>(Minderhoud et al. 2024)</span>.</figcaption> </figure>

Definition : Degree of the bending of the centerline and the deviation from a straight line in one plane (Minderhoud et al. 2024).
Calculation: For the centerline c(s), the analytical form is $\kappa(s)=\frac{|c'(s)\times c''(s)|}{|c'(s)|^3}$ (Piccinelli et al. 2009). For the geometric interpretation, $\kappa=\frac{1}{r}$ where r is the radius of the osculating circle (Minderhoud et al. 2024).
Acquisition Type: Thoracic scout MRI

Reference Range:

Study	Cohort Size	Gender	Reference Value (mm<sup>−1</sup>)	Note
(Redheuil et al. 2011)	45	male	(0.029, 0.004)	average age 45 years
	55	female	(0.032, 0.004)	average age 48 years
(Minderhoud et al. 2024)	23		0.034-0.040	11 males, 12 females, average age 30 years

Clinical Associations: In patients with repaired coarctation of the aorta (CoA), curvature is increased compared to controls (Minderhoud et al. 2024).

Torsion

Definition: The twist of the centerline and the degree of the deviation of the curve from the osculating plane (Minderhoud et al. 2024).
Calculation: For the centerline c(s), $\tau(s)=\frac{[c'(s)\times c''(s)]\times c'''(s)}{|c'(s)\times c(s)|}$ (Piccinelli et al. 2009).
Acquisition Type: Thoracic scout MRI
Reference Range:
Study Cohort Size Reference Value (mm<sup>−1</sup>) Note
(Minderhoud et al. 2024) 23 0.08-0.13 11 males, 12 females, average age 30 years
Clinical Associations: In patients with repaired coarctation of the aorta (CoA), torsion is increased compared to controls (Minderhoud et al. 2024).

Study	Cohort Size	Reference Value (mm<sup>−1</sup>)	Note
(Minderhoud et al. 2024)	23	0.08-0.13	11 males, 12 females, average age 30 years

Tortuosity

Definition: The relative increment in the length of a curve deviating from a rectilinear line (Piccinelli et al. 2009).
Calculation 1: The ratio of the centerline length L and the direct distance D between the centerline endpoints $\chi=\frac{L}{D}$ . (Boufi et al. 2017; Cao et al. 2020; Sun et al. 2021; Minderhoud et al. 2024).
Calculation 2: The ratio of the centerline length L and the direct distance D between the centerline endpoints, subtracted by 1: $\chi=\frac{L}{D}-1$ (Piccinelli et al. 2009).
Calculation 3: The ratio of arch length divided by arch width (Alhafez et al. 2019).
Acquisition Type: Thoracic scout MRI
Reference Range:
1. Ascending aorta, measured according to calculation 1:
  Study Cohort Size Reference Value (%) Note
  (Sun et al. 2021) 168 (115.3, 6.7) 137 males, 31 females, average age 56.5 years
  (Cao et al. 2020) 127 (112.2, 3.9) 106 males, 21 females, average age 56.3 years
2. Aortic arch, measured according to calculation 1:
  Study Cohort Size Reference Value (%) Note
  (Sun et al. 2021) 168 (106.5, 5.7) 137 males, 31 females, average age 56.5 years
  (Cao et al. 2020) 127 (102.3, 1.3) 106 males, 21 females, average age 56.3 years
3. Aortic arch, measured according to calculation 3:
  Study Cohort Size Reference Value (%) Note
  (Alhafez et al. 2019) 234 146-156 155 males, 79 females, average age 54 years
4. STJ to distal LSA, measured according to calculation 1:
  Study Cohort Size Reference Value (%) Note
  (Sun et al. 2021) 168 (131.8, 6.4) 137 males, 31 females, average age 56.5 years
  (Cao et al. 2020) 127 (123.0, 4.9) 106 males, 21 females, average age 56.3 years
5. STJ to the level of fourth thoracic vertebra body upper edge, measured according to calculation 1:
  Study Cohort Size Reference Value (%) Note
  (Boufi et al. 2017) 123 (119, 1) 73 males, 50 females, average age 53 years
6. STJ to aortic bifurcation, measured according to calculation 1:
  Study Cohort Size Reference Value (%) Note
  (Sun et al. 2021) 168 (187.8, 20.3) 137 males, 31 females, average age 56.5 years
Clinical Associations: Tortuosity of aorta is increased in TBAD patients who develop enlarging thoracoabdominal aneurysms or ruptures, as well as BAV patients (Alhafez et al. 2019). The aortic arch and total aorta tortuosities are also elevated in the TBAD group, but not the one of ascending aorta (Cao et al. 2020; Sun et al. 2021).

Study	Cohort Size	Reference Value (%)	Note
(Sun et al. 2021)	168	(115.3, 6.7)	137 males, 31 females, average age 56.5 years
(Cao et al. 2020)	127	(112.2, 3.9)	106 males, 21 females, average age 56.3 years

Study	Cohort Size	Reference Value (%)	Note
(Sun et al. 2021)	168	(106.5, 5.7)	137 males, 31 females, average age 56.5 years
(Cao et al. 2020)	127	(102.3, 1.3)	106 males, 21 females, average age 56.3 years

Study	Cohort Size	Reference Value (%)	Note
(Alhafez et al. 2019)	234	146-156	155 males, 79 females, average age 54 years

Study	Cohort Size	Reference Value (%)	Note
(Sun et al. 2021)	168	(131.8, 6.4)	137 males, 31 females, average age 56.5 years
(Cao et al. 2020)	127	(123.0, 4.9)	106 males, 21 females, average age 56.3 years

Study	Cohort Size	Reference Value (%)	Note
(Boufi et al. 2017)	123	(119, 1)	73 males, 50 females, average age 53 years

Study	Cohort Size	Reference Value (%)	Note
(Sun et al. 2021)	168	(187.8, 20.3)	137 males, 31 females, average age 56.5 years

Angulation

Definition: The angle between tangent lines drawn at two points along the centerline, or between two anatomical planes (Boufi et al. 2017; Cao et al. 2020).
Acquisition Type: Thoracic scout MRI
Reference Range:
1. Ascending aorta according to the anatomical segmentation:
  Study Cohort Size Reference Value () Note
  (Sun et al. 2021) 168 (80.6, 12.1) 137 males, 31 females, average age 56.5 years
  (Cao et al. 2020) 127 (79.7, 10.8) 106 males, 21 females, average age 56.3 years
2. Aortic arch according to the anatomical segmentation:
  Study Cohort Size Reference Value () Note
  (Sun et al. 2021) 168 (41.2, 10.9) 137 males, 31 females, average age 56.5 years
  (Cao et al. 2020) 127 (41.7, 11.1) 106 males, 21 females, average age 56.3 years
3. From STJ to the distal edge of left subclavian artery:
  Study Cohort Size Reference Value () Note
  (Sun et al. 2021) 168 (106.8, 11.3) 137 males, 31 females, average age 56.5 years
4. From pulmonary trunk bifurcation to the distal edge of innominate artery:
  Study Cohort Size Reference Value () Note
  (Boufi et al. 2017) 123 (46, 2.3) 73 males, 50 females, average age 53 years
5. From the distal edge of innominate artery to the distal edge of left common carotid artery:
  Study Cohort Size Reference Value () Note
  (Boufi et al. 2017) 123 (13, 1.24) 73 males, 50 females, average age 53 years
6. From the distal edge of left common carotid artery to distal edge of the left subclavian artery:
  Study Cohort Size Reference Value () Note
  (Boufi et al. 2017) 123 (23, 1.41) 73 males, 50 females, average age 53 years
7. From the distal edge of left subclavian artery to the level of the fourth thoracic vertebra body under edge:
  Study Cohort Size Reference Value () Note
  (Boufi et al. 2017) 123 (35, 3) 73 males, 50 females, average age 53 years
Clinical Associations: Angulation of the ascending aorta plays an independent role in the development of type A aortic dissection (TAAD) (Cao et al. 2020). Higher angulations of the ascending aorta and the aortic arch are also observed in TBAD patients (Cao et al. 2020; Sun et al. 2021).

Study	Cohort Size	Reference Value ()	Note
(Sun et al. 2021)	168	(80.6, 12.1)	137 males, 31 females, average age 56.5 years
(Cao et al. 2020)	127	(79.7, 10.8)	106 males, 21 females, average age 56.3 years

Study	Cohort Size	Reference Value ()	Note
(Sun et al. 2021)	168	(41.2, 10.9)	137 males, 31 females, average age 56.5 years
(Cao et al. 2020)	127	(41.7, 11.1)	106 males, 21 females, average age 56.3 years

Study	Cohort Size	Reference Value ()	Note
(Sun et al. 2021)	168	(106.8, 11.3)	137 males, 31 females, average age 56.5 years

Study	Cohort Size	Reference Value ()	Note
(Boufi et al. 2017)	123	(46, 2.3)	73 males, 50 females, average age 53 years

Study	Cohort Size	Reference Value ()	Note
(Boufi et al. 2017)	123	(13, 1.24)	73 males, 50 females, average age 53 years

Study	Cohort Size	Reference Value ()	Note
(Boufi et al. 2017)	123	(23, 1.41)	73 males, 50 females, average age 53 years

Study	Cohort Size	Reference Value ()	Note
(Boufi et al. 2017)	123	(35, 3)	73 males, 50 females, average age 53 years

Arch Type*

<figure> <img src="/latex/images/aorta/aorta_arch_type.png" id="fig:aorta_arch_type" alt="Aortic arch classification in types I to III of the normal aorta (Sun et al. 2021)." /><figcaption aria-hidden="true">Aortic arch classification in types I to III of the normal aorta <span>(Sun et al. 2021)</span>.</figcaption> </figure>

Definition: Aortic arch type can be divided into three types (Sun et al. 2021):
1. Type I arch: The vertical distance from the origin of the innominate artery (IA) to the arch vertex is < 1 time diameter of the left common carotid artery (LCCA).
2. Type II arch: the distance ranges is between 1 and 2 times the LCCA diameter.
3. Type III arch: the distance exceeds 2 times the LCCA diameter.
Acquisition Type: Thoracic scout MRI
Clinical Associations: A significantly higher proportion of type III aortic arch is observed in patients with acute TBAD compared to controls (Sun et al. 2021).

Aortic Root

The aortic root extends from the annulus to the sinotubular junction (STJ), and comprises the sinuses of Valsalva, with the aortic cusps, the coronary origins, and the inter-cuspal triangles. The annulus is a virtual circular line running through the base of the aortic cusps. It lies both to the anatomic ventricular-aortic junction (where cardiac myocytes leave the place to smooth muscle cells of the aortic wall) and the hemodynamic junction, identified by the crown-like attachment of the aortic cusps to the sinuses wall. The STJ is a virtual circular line running through the tip of the aortic valve commissures. As for the sinuses of Valsalva, its wall is thinner as compared to the wall of the aorta (about 2 mm versus 4 mm) (Di Gioia et al. 2023).

<figure> <img src="/latex/images/aorta/LVOT1.png" id="fig:LOVT2" alt="The aortic root is the segment between the annulus (red dashed line) and the sinotubular junction (black dotted line). It comprises the sinuses of Valsalva with the aortic cusps, as outlined with the orange dashed line (Di Gioia et al. 2023)." /><figcaption aria-hidden="true">The aortic root is the segment between the annulus (red dashed line) and the sinotubular junction (black dotted line). It comprises the sinuses of Valsalva with the aortic cusps, as outlined with the orange dashed line <span>(Di Gioia et al. 2023)</span>.</figcaption> </figure>

<figure> <img src="/latex/images/aorta/LVOT2.png" id="fig:LOVT2" alt="The aortic root is the segment between the annulus (red dashed line) and the sinotubular junction (black dotted line). It comprises the sinuses of Valsalva with the aortic cusps, as outlined with the orange dashed line (Di Gioia et al. 2023)." /><figcaption aria-hidden="true">The aortic root is the segment between the annulus (red dashed line) and the sinotubular junction (black dotted line). It comprises the sinuses of Valsalva with the aortic cusps, as outlined with the orange dashed line <span>(Di Gioia et al. 2023)</span>.</figcaption> </figure>

Other schematic representation can also be found in (Roman et al. 1987; Erbel 2006; Burman, Keegan, and Kilner 2008; de Kerchove and El Khoury 2013).

Annulus Diameter

Definition: The diameter of aortic annulus.
Acquisition Type: LVOT

Reference Range:

Study	Cohort Size	Reference Value (mm)	Note
(Kawel-Boehm et al. 2020)	299	male	(23, 5)
	328	female	(20, 3)
(Zhao et al. 2023)	58		(22.4, 2.5)	35 males, 23 females, age ranges: 21-36 years
	56		(21.8, 2.3)	30 males, 26 females, age ranges: 37-50 years
	55		(21.0, 2.1)	31 males, 24 females, age ranges: 51-76 years
(Vriz et al. 2014)	503	male	(21.0, 2.2)
	540	female	(18.7, 1.6)
(Davis et al. 2014)	208	male	18.6-29.2	average age 36 years
	239	female	17.4-23.8	average age 38 years

Clinical Associations: Aortic annulus dilation is the most common definable cause of severe aortic regurgitation (AR) (Roman et al. 1987; Padial et al. 1997).
ICC: 0.81

Sinuses of Valsalva Diameter

Definition: The diameter of aortic sinuses of Valsalva.
Acquisition Type: LVOT

Reference Range:

Study	Cohort Size	Reference Value (mm)	Note
(Kawel-Boehm et al. 2020)	359	male	(32, 6)
	328	female	(28, 5)
(Burman, Keegan, and Kilner 2008)	60	male	(34, 3)	measured at systole in sinus plane image, cusp-commissure view
	60	male	(32, 4)	measured at diastole in sinus plane image, cusp-commissure view
	60	female	(30, 3)	measured at systole in sinus plane image, cusp-commissure view view
	60	female	(28, 3)	measured at diastole in sinus plane image, cusp-commissure view
	60	male	(36, 4)	measured at systole in sinus plane image, cusp-cusp view
	60	male	(35, 4)	measured at diastole in sinus plane image, cusp-cusp view
	60	female	(32, 3)	measured at systole in sinus plane image, cusp-cusp view view
	60	female	(31, 3)	measured at diastole in sinus plane image, cusp-cusp view
(Zhao et al. 2023)	58		(27.7, 3.4)	35 males, 23 females, age ranges: 21-36 years
	56		(28.4, 3.3)	30 males, 26 females, age ranges: 37-50 years
	55		(30.4, 3.3)	31 males, 24 females, age ranges: 51-76 years
(Vriz et al. 2014)	503	male	(31.8, 3.7)
	540	female	(28,5, 3.0)
(Davis et al. 2014)	208	male	24.3-39.5	average age 36 years
	239	female	21.9-33.1	average age 38 years

Clinical Associations: Measuring at the level of the sinuses of Valsalva has the potential to predict aortic root dilation, a critical prognostic marker in Marfan syndrome (MFS) for assessing the risk of life-threatening complications such as aortic dissection or rupture (Cox et al. 2022). It is also associated with severe AR (Roman et al. 1987; Padial et al. 1997).
ICC: 0.89

Sinotubular Junction Diameter

Definition: The diameter of sinotubular junction (STJ).
Acquisition Type: LVOT

Reference Range:

Study	Cohort Size	Reference Value (mm)	Note
(Kawel-Boehm et al. 2020)	299	male	(25, 6)
	328	female	(21, 5)
(Zhao et al. 2023)	58		(22.1, 2.6)	35 males, 23 females, age ranges: 21-36 years
	56		(23.6, 3.0)	30 males, 26 females, age ranges: 37-50 years
	55		(24.7, 2.6)	31 males, 24 females, age ranges: 51-76 years
(Vriz et al. 2014)	503	male	(26.9, 3.7)
	540	female	(24.4, 2.9)
(Davis et al. 2014)	208	male	18.2-30.6	average age 36 years
	239	female	16.6-26.6	average age 38 years
(Sun et al. 2021)	168		(29.2, 2.8)	137 males, 31 females, average age 56.5 years

Clinical Associations: When indexed to BSA, the diameters from the aortic sinus to the level of the right pulmonary artery, including the sinotubular junction, are significantly increased in patients with conotruncal defects such as tetralogy of Fallot (TOF) and complete transposition of the great arteries (TGA) (Rutz et al. 2012). It associated with severe AR as well (Roman et al. 1987; Padial et al. 1997).
ICC: 0.78

Alhafez, Bader Aldeen, Van Thi Thanh Truong, Daniel Ocazionez, Sahand Sohrabi, Harleen Sandhu, Anthony Estrera, Hazim J. Safi, et al. 2019. “Aortic Arch Tortuosity, a Novel Biomarker for Thoracic Aortic Disease, Is Increased in Adults with Bicuspid Aortic Valve.” International Journal of Cardiology 284: 84–89.

</div>

Assadi, Hosamadin, Gareth Matthews, Xiaodan Zhao, Rui Li, Samer Alabed, Ciaran Grafton-Clarke, Zia Mehmood, et al. 2023. “Cardiac MR Modelling of Systolic and Diastolic Blood Pressure.” Open Heart 10 (2): e002484.

</div>

Beeche, C, MJ Dib, B Zhao, JD Azzo, H Maynard, J Duda, J Gee, et al. 2024. “Three-Dimensional Aortic Geometry: Clinical Correlates, Prognostic Value and Genetic Architecture.” Biorxiv: The Preprint Server for Biology.

</div>

Boufi, M., C. Guivier-Curien, A. D. Loundou, V. Deplano, O. Boiron, K. Chaumoitre, V. Gariboldi, and Y. S. Alimi. 2017. “Morphological Analysis of Healthy Aortic Arch.” European Journal of Vascular and Endovascular Surgery 53 (5): 663–70.

</div>

Burman, Elisabeth D., Jennifer Keegan, and Philip J. Kilner. 2008. “Aortic Root Measurement by Cardiovascular Magnetic Resonance: Specification of Planes and Lines of Measurement and Corresponding Normal Values.” Circulation: Cardiovascular Imaging 1 (2): 104–13.

</div>

Cao, Long, Weihang Lu, Yangyang Ge, Xinhao Wang, Yuan He, Guoyi Sun, Jie Liu, et al. 2020. “Altered Aortic Arch Geometry in Patients with Type B Aortic Dissection.” European Journal of Cardio-Thoracic Surgery 58 (4): 714–21.

</div>

Cox, Kelly, Yousi A. Oquendo, David Liang, and Elif Seda Selamet Tierney. 2022. “Aortic Root Dilation in Adult Patients with Marfan Syndrome: Does Aortic Root Stiffness Matter?” JTCVS Open 10: 113–20.

</div>

Davis, Anne E, Adam J Lewandowski, Cameron J Holloway, Ntobeko AB Ntusi, Rajarshi Banerjee, Richard Nethononda, Alex Pitcher, et al. 2014. “Observational Study of Regional Aortic Size Referenced to Body Size: Production of a Cardiovascular Magnetic Resonance Nomogram.” Journal of Cardiovascular Magnetic Resonance 16 (1): 9.

</div>

de Kerchove, Laurent, and Gebrine El Khoury. 2013. “Anatomy and Pathophysiology of the Ventriculo-Aortic Junction: Implication in Aortic Valve Repair Surgery.” Annals of Cardiothoracic Surgery 2 (1): 57–64.

</div>

Di Gioia, Cira Rosaria Tiziana, Andrea Ascione, Raffaella Carletti, and Carla Giordano. 2023. “Thoracic Aorta: Anatomy and Pathology.” Diagnostics 13 (13): 2166.

</div>

Eikendal, Anouk L. M., Michiel L. Bots, Cees Haaring, Tobias Saam, Rob J. Van Der Geest, Jos J. M. Westenberg, Hester M. Den Ruijter, Imo E. Hoefer, and Tim Leiner. 2016. “Reference Values for Cardiac and Aortic Magnetic Resonance Imaging in Healthy, Young Caucasian Adults.” Edited by John Lynn Jefferies. PLOS ONE 11 (10): e0164480. https://doi.org/10.1371/journal.pone.0164480.

</div>

Erbel, R. 2006. “Aortic Dimensions and the Risk of Dissection.” Heart 92 (1): 137–42.

</div>

Francois, Katrien. 2015. “Aortopathy Associated with Congenital Heart Disease: A Current Literature Review.” Annals of Pediatric Cardiology 8 (1): 25.

</div>

Girsowicz, Elie, Yannick Georg, François Lefebvre, Anne Lejay, Fabien Thaveau, Catherine Roy, Mickael Ohana, and Nabil Chakfe. 2017. “Anatomical Study of Healthy Aortic Arches.” Annals of Vascular Surgery 44: 179–89.

</div>

Kawel-Boehm, Nadine, Scott J. Hetzel, Bharath Ambale-Venkatesh, Gabriella Captur, Christopher J. Francois, Michael Jerosch-Herold, Michael Salerno, et al. 2020. “Reference Ranges (‘Normal Values’) for Cardiovascular Magnetic Resonance (CMR) in Adults and Children: 2020 Update.” Journal of Cardiovascular Magnetic Resonance 22 (1): 87.

</div>

Kurugol, Sila, Carolyn E. Come, Alejandro A. Diaz, James C. Ross, Greg L. Kinney, Jennifer L. Black-Shinn, John E. Hokanson, Matthew J. Budoff, George R. Washko, and Raul San Jose Estepar. 2015. “Automated Quantitative 3d Analysis of Aorta Size, Morphology, and Mural Calcification Distributions.” Medical Physics 42 (9): 5467–78.

</div>

Mehmood, Zia, Hosamadin Assadi, Rui Li, Bahman Kasmai, Gareth Matthews, Ciaran Grafton-Clarke, Aureo Sanz-Cepero, et al. 2024. “Aortic Flow Is Abnormal in HFpEF [Version 2; Peer Review:” Wellcome Open Research.

</div>

Minderhoud, Savine C S, Rick van Montfoort, Timion A Meijs, Suze-Anne Korteland, Jan L Bruse, Isabella Kardys, Jolanda J Wentzel, et al. 2024. “Aortic Geometry and Long-Term Outcome in Patients with a Repaired Coarctation.” Open Heart 11 (1): e002642.

</div>

Obel, Lasse M., Axel C. Diederichsen, Flemming H. Steffensen, Lars Frost, Jess Lambrechtsen, Martin Busk, Grazina Urbonaviciene, et al. 2021. “Population-Based Risk Factors for Ascending, Arch, Descending, and Abdominal Aortic Dilations for 60-74–Year-Old Individuals.” Journal of the American College of Cardiology 78 (3): 201–11.

</div>

Olivieri, Laura J., Ridhwan Y. Baba, Andrew E. Arai, W. Patricia Bandettini, Douglas R. Rosing, Vladimir Bakalov, Vandana Sachdev, and Carolyn A. Bondy. 2013. “Spectrum of Aortic Valve Abnormalities Associated with Aortic Dilation Across Age Groups in Turner Syndrome.” Circulation. Cardiovascular Imaging 6 (6): 1018–23.

</div>

Padial, Luis R., Alvaro Oliver, Alex Sagie, Arthur E. Weyman, Mary Etta King, and Robert A. Levine. 1997. “Two-Dimensional Echocardiographic Assessment of the Progression of Aortic Root Size in 127 Patients with Chronic Aortic Regurgitation: Role of the Supraaortic Ridge and Relation to the Progression of the Lesion.” American Heart Journal 134 (5): 814–21.

</div>

Philip, Femi, Nadine Nadar Faza, Paul Schoenhagen, Milind Y. Desai, E. Murat Tuzcu, Lars G. Svensson, and Samir R. Kapadia. 2015. “Aortic Annulus and Root Characteristics in Severe Aortic Stenosis Due to Bicuspid Aortic Valve and Tricuspid Aortic Valves: Implications for Transcatheter Aortic Valve Therapies.” Catheterization and Cardiovascular Interventions 86 (2).

</div>

Piccinelli, Marina, Alessandro Veneziani, David A. Steinman, Andrea Remuzzi, and Luca Antiga. 2009. “A Framework for Geometric Analysis of Vascular Structures: Application to Cerebral Aneurysms.” IEEE Transactions on Medical Imaging 28 (8): 1141–55.

</div>

Qiu, Peng, Junchao Liu, Yuqian Chen, Binshan Zha, Kaichuang Ye, Jinbao Qin, Peipei Hao, et al. 2020. “Changes in Aortic Arch Geometry and the Risk for Stanford B Dissection.” Journal of Thoracic Disease 12 (12): 7193–7201.

</div>

Redheuil, Alban, Wen-Chung Yu, Elie Mousseaux, Ahmed A. Harouni, Nadjia Kachenoura, Colin O. Wu, David Bluemke, and Joao A. C. Lima. 2011. “Age-Related Changes in Aortic Arch Geometry.” Journal of the American College of Cardiology 58 (12): 1262–70.

</div>

Roman, Mary J., Richard B. Devereux, Nathaniel W. Niles, Clare Hochreiter, Paul Kligfield, Nina Sato, Mariane C. Spitzer, and Jeffrey S. Borer. 1987. “Aortic Root Dilatation as a Cause of Isolated, Severe Aortic Regurgitation: Prevalence, Clinical and Echocardiographic Patterns, and Relation to Left Ventricular Hypertrophy and Function.” Annals of Internal Medicine 106 (6): 800–807.

</div>

Rutz, Tobias, Friedrich Max, Andreas Wahl, Kerstin Wustmann, Kerstin Khattab, Jean-Pierre Pfammatter, Alexander Kadner, and Markus Schwerzmann. 2012. “Distensibility and Diameter of Ascending Aorta Assessed by Cardiac Magnetic Resonance Imaging in Adults With Tetralogy of Fallot or Complete Transposition.” The American Journal of Cardiology 110 (1): 103–8.

</div>

Singh, Anvesha, Mark A. Horsfield, Soliana Bekele, John P. Greenwood, Dana K. Dawson, Colin Berry, Kai Hogrefe, et al. 2019. “Aortic Stiffness in Aortic Stenosis Assessed by Cardiovascular MRI: A Comparison Between Bicuspid and Tricuspid Valves.” European Radiology 29 (5): 2340–49.

</div>

Sun, Likun, Jiehua Li, Lunchang Wang, Quanming Li, Hao He, Xin Li, Ming Li, et al. 2021. “Aortic Geometric Alteration Associated With Acute Type B Aortic Dissection: Angulation, Tortuosity, and Arch Type.” Frontiers in Physiology 12: 708651.

</div>

Turkbey, Evrim B., Aditya Jain, Craig Johnson, Alban Redheuil, Andrew E. Arai, Antoinette S. Gomes, James Carr, et al. 2014. “Determinants and Normal Values of Ascending Aortic Diameter by Age, Gender, and Race/Ethnicity in the Multi-Ethnic Study of Atherosclerosis (MESA).” Journal of Magnetic Resonance Imaging 39 (2): 360–68.

</div>

Vriz, Olga, Victor Aboyans, Antonello D’Andrea, Francesco Ferrara, Edvige Acri, Giuseppe Limongelli, Alessandro Della Corte, et al. 2014. “Normal Values of Aortic Root Dimensions in Healthy Adults.” The American Journal of Cardiology 114 (6): 921–27.

</div>

Wolak, Arik, Heidi Gransar, Louise E. J. Thomson, John D. Friedman, Rory Hachamovitch, Ariel Gutstein, Leslee J. Shaw, et al. 2008. “Aortic Size Assessment by Noncontrast Cardiac Computed Tomography: Normal Limits by Age, Gender, and Body Surface Area.” JACC: Cardiovascular Imaging 1 (2): 200–209.

</div>

Zhao, Xiaodan, Pankaj Garg, Hosamadin Assadi, Ru-San Tan, Ping Chai, Tee Joo Yeo, Gareth Matthews, et al. 2023. “Aortic Flow Is Associated with Aging and Exercise Capacity.” European Heart Journal Open 3 (4): oead079.

</div>