Three-Dimensional Modeling Analysis of Visceral Arteries and Kidneys during Respiration.
BACKGROUND
Visceral arteries are commonly involved in endovascular repair of complex abdominal aortic aneurysms (AAAs). To improve repair techniques and reduce long-term complications involving visceral arteries, it is crucial to understand in vivo arterial geometry and the deformations due to visceral organ movement with respiration. This study quantifies deformation of the celiac, superior mesenteric (SMA), and renal arteries during respiration and correlates the deformations with diaphragmatic excursion.


METHODS
Sixteen patients with small AAAs underwent magnetic resonance angiography during inspiratory and expiratory breathholds. From geometric models of the aorta and visceral arteries, vessel length, branch angle, curvature, and positions were computed, along with degree of diaphragmatic excursion as indicated by kidney translation.


RESULTS
From inspiration to expiration, the celiac artery exhibited axial shortening of 4.8 ± 6.4% (P < 0.001) and a mean curvature increase of 0.03 ± 0.02 mm(-1), greater than other visceral arteries (P < 0.01). With expiration, the SMA, left and right renal arteries (LRA and RRA) angled upward by -9.8 ± 6.4°, -6.4 ± 6.4°, and -5.2 ± 5.0°, respectively (P < 0.005). All vessels translated superiorly (P < 0.0005) and posteriorly (P < 0.01), and the SMA translated rightward additionally (P < 0.005). The left and right kidneys translated by 22 ± 9 mm and 21 ± 9 mm, mostly superiorly (P < 0.001). Translations of all visceral arteries were moderately correlated to the right kidney (R > 0.50). Correlation of the LRA with the left kidney was greater than that of the RRA with the right kidney.


CONCLUSIONS
The celiac artery exhibited less branch angle change, and greater axial and curvature deformations than the other visceral arteries, due to the vicinity to the liver and influence of the median arcuate ligament. Correlation between visceral arteries and kidney translations revealed that diaphragmatic excursion affects vessel mobility. Weaker correlation of the RRA to the right kidney indicates mechanical shielding from the inferior vena cava.
Department of Surgery, Stanford University, Stanford, CA. Electronic address: gysuh@stanford.edu.
Ga-Young
GY
Suh
Department of Surgery, Stanford University, Stanford, CA.
Gilwoo
G
Choi
Department of Radiology, Stanford University, Stanford, CA.
Robert J
RJ
Herfkens
Department of Surgery, Stanford University, Stanford, CA.
Ronald L
RL
Dalman
Department of Surgery, Stanford University, Stanford, CA.
Christopher P
CP
Cheng
D000368:Aged; D000369:Aged, 80 and over; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging* / Q000503:physiopathology; D062485:Breath Holding; D002445:Celiac Artery / Q000000981:diagnostic imaging*; D045853:Exhalation; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D021621:Imaging, Three-Dimensional; D001239:Inhalation; D007668:Kidney / Q000000981:diagnostic imaging*; D018810:Magnetic Resonance Angiography; D008297:Male; D017538:Mesenteric Artery, Superior / Q000000981:diagnostic imaging*; D008955:Models, Cardiovascular; D009068:Movement; D011237:Predictive Value of Tests; D012077:Renal Artery / Q000000981:diagnostic imaging*; D012119:Respiration