Right aortic arch analysis - Anatomical variant or serious vascular defect?

BACKGROUND: The right-sided aortic arch (RAA) is a rare congenital defect of the aorta. The aim of the study was to assess the occurrence of RAA in diagnoses performed by the University Radiology Department and analyze the frequency of concomitant vascular abnormalities. METHODS: The database of the Radiology Department was retrospectively analyzed between January 2008 and May 2016 with the keyword "right aortic arch". Twenty patients with this diagnosis were identified from a total of 11,690 CT examinations of the chest area, 19,623 CT examinations of brain-supplying vessels, and 1863 MRI examinations of the heart and aortic arch or brain-supplying arteries. The type of aortic arch, the occurrence of Kommerell's diverticulum and possible other vascular abnormalities, such as stenosis, kinking or occlusion, were then investigated. RESULTS: The analysis identified nine patients with type I and 11 patients with type II RAA. Eight of the 11 type II patients presented Kommerell's diverticulum. Concomitant vascular abnormalities were detected in four patients with type II RAA. In two cases, the right common carotid artery (RCCA) was narrowed by up to 80%, with steal phenomenon confirmed in one of them. In the second coincident right subclavian artery (RSA) stenosis was depicted. In two other cases, the aberrant left subclavian arteries (ALSA) were found to be narrowed at the level of origin by up to 70%. One patient was found with type B aortic dissection including ALSA and Kommerell's diverticulum. CONCLUSIONS: Our observations indicate that concomitant vascular abnormalities may occur more often than reported in literature. Patients diagnosed with type II RAA should be examined with Doppler ultrasonography to identify coincident vascular disorders, especially stenosis of the common carotid arteries or subclavian arteries.

Median arcuate ligament syndrome: Predictor of ischemic complications?

Median arcuate ligament syndrome (MALS) is a pathologic entity that can affect the celiac axis. Due to the extensive collateral network of mesenteric circulation, stenosis of one mesenteric artery does not lead to significant symptoms. The purpose of this study was to describe multidetector computed tomography (MDCT) angiography findings of celiac artery entrapment by the median arcuate ligament and determine those patients with high risks of ischemic complications. From January 2012 to March 2016, 103 patients with celiac artery (CA) compression by median arcuate ligament were detected. In 23 patients collateral circulation was developed. In order to investigate the problem, we managed to estimate the correlation between range of stenosis of CA and presence of collateral circulation between the celiac artery (CA) and superior mesenteric artery (SMA). A statistically significant correlation was found between range of CA stenosis and collateral circulation presence (Spearman's correlation coefficient 0.339, P < 0.0001). In conclusions, based on our observations, we hypothesize that ischemia as a result of mesenteric vessel narrowing by the median arcuate ligament may occur more often than indicated by clinical symptoms and described in literature. Clin. Anat. 29:1025-1030, 2016. © 2016 Wiley Periodicals, Inc.

A Novel Attempt to Standardize Results of CFD Simulations Basing on Spatial Configuration of Aortic Stent-Grafts.

Currently, studies connected with Computational Fluid Dynamic (CFD) techniques focus on assessing hemodynamic of blood flow in vessels in different conditions e.g. after stent-graft's placement. The paper propose a novel method of standardization of results obtained from calculations of stent-grafts' "pushing forces" (cumulative WSS--Wall Shear Stress), and describes its usefulness in diagnostic process. AngioCT data from 27 patients were used to reconstruct 3D geometries of stent-grafts which next were used to create respective reference cylinders. We made an assumption that both the side surface and the height of a stent-graft and a reference cylinder were equal. The proposed algorithm in conjunction with a stent-graft "pushing forces" on an implant wall, allowed us to determine which spatial configuration of a stent-graft predispose to the higher risk of its migration. For stent-grafts close to cylindrical shape (shape factor φ close to 1) WSS value was about 267 Pa, while for stent-grafts different from cylindrical shape (φ close to 2) WSS value was about 635 Pa. It was also noticed that deformation in the stent-graft's bifurcation part impaired blood flow hemodynamic. Concluding the proposed algorithm of standardization proved its usefulness in estimating the WSS values that may be useful in diagnostic process. Angular bends or tortuosity in bifurcations of an aortic implant should be considered in further studies of estimation of the risk of implantation failure.

An unusual case of left renal artery compression: a rare type of median arcuate ligament syndrome.

Compression from median arcuate ligament was observed during multidetector 64-row computed tomography in a Caucasian 30-year-old female. The patient was referred for examination to exclude anatomical pathologies causing hypertension. The examination demonstrated that left renal artery, which had its origin in the chest (at the level of upper one-third of Th12), was compressed as it passed by median arcuate ligament of the diaphragm. In addition, aortic compression and kinked shape was also revealed.