ABSTRACT
To examine the feasibility of the quantification of abdominal periaortic fat tissue (PaFT) (tissue within - 45 to - 195 HU) in enhanced CT-angiographies compared to unenhanced CT-scans and identify methodological issues affecting its clinical implementation. Using OsirixMD, PaFT volume and mean HU value were retrospectively measured within a 5 mm periaortic ring in paired unenhanced and enhanced abdominal aortic CT-scans. The correlation between PaFT values was examined in a derivation cohort (n = 101) and linear regression analysis produced correction factors to convert values from enhanced into values from unenhanced CTs. The conversion factors were then applied to enhanced CTs in a different validation cohort (n = 47) and agreement of corrected enhanced values with values from unenhanced scans was evaluated. Correlation between PaFT Volume und Mean HU from enhanced and unenhanced scans was very high (r > 0.99 and r = 0.95, respectively, p < 0.0001 for both). The correction factors for PaFT Volume and Mean HU were 1.1057 and 1.0011. Potential confounding factors (CT-kilovoltage, slice thickness, mean intraluminal contrast density, aortic wall calcification, longitudinal variation of intraluminal contrast density, aortic diameter) showed no significant effect in a multivariate regression analysis (p > 0.05). Bland-Altman analysis of corrected enhanced and unenhanced values showed excellent agreement and Passing-Bablok regression confirmed minimal/no residual bias. PaFT can be quantified in enhanced CT-angiographies very reliably. PaFT Volume scores are very consistently slightly underestimated in enhanced scans by about 10%, while the PaFT Mean HU value remains practically constant and offers distinct methodological advantages. However, a number of methodological issues remain to be addressed.
ABSTRACT
A right-sided aortic arch is a rare anomaly with an incidence of 0.1% worldwide and is usually associated with a mirror image of all supra-aortic branches or an aberrant left subclavian artery. The latter is often associated with a Kommerell diverticulum, although it can rarely be hypoplastic or atretic and lead to congenital subclavian steal. In most patients, the situation is well-tolerated. In this report, we present a case of subclavian steal syndrome with multiple cerebellar infarcts in a patient with an atypical right-sided aortic arch and an atretic aberrant left subclavian artery arising from a left-sided descending thoracic aorta.
Subject(s)
Aneurysm/complications , Aorta, Thoracic/abnormalities , Cardiovascular Abnormalities/complications , Cerebral Infarction/etiology , Deglutition Disorders/complications , Subclavian Artery/abnormalities , Subclavian Steal Syndrome/etiology , Aneurysm/diagnosis , Aneurysm/surgery , Aortography/methods , Cardiovascular Abnormalities/diagnosis , Cardiovascular Abnormalities/surgery , Cerebral Angiography/methods , Cerebral Infarction/diagnosis , Deglutition Disorders/diagnosis , Deglutition Disorders/surgery , Humans , Magnetic Resonance Angiography , Male , Middle Aged , Subclavian Artery/surgery , Subclavian Steal Syndrome/diagnosis , Subclavian Steal Syndrome/surgery , Tomography, X-Ray Computed , Treatment OutcomeABSTRACT
Retrograde ascending aortic dissections usually complicate endovascular reconstructions of Stanford B dissections. Although rare, with an incidence of 1.3% to 6.8%, they are catastrophic, with a high mortality rate of up to 42%. The exact mechanism is not known, but all indications point to a mechanical interaction between the tips of the proximal bare stent and a fragile aortic wall. Practically all reported cases involve dissections of the thoracic aorta. We report a patient with an asymptomatic retrograde ascending aortic dissection that originated at the level of a damaged suprarenal stent during capture tip retrieval during a routine endovascular aneurysm repair to treat an infrarenal aortic aneurysm.