Background: The ultimate goal of treating patients with abdominal aortic aneurysms (AAAs) is to repair them when the risk of rupture exceeds the risk of repair. Small AAAs demonstrate a low rupture risk, and recently, large AAAs just above the threshold (5.5–6.0 cm) seem to be at low risk of rupture as well. The present review aims to investigate the outcomes of AAAs under surveillance through a comprehensive systematic review and meta-analysis. Methods: PubMed, Embase, and the Cochrane Central Register were searched (22 March 2022; PROSPERO; #CRD42022316094). The Cochrane and PRISMA statements were respected. Blinded systematic screening of the literature, data extraction, and quality assessment were performed by two authors. Conflicts were resolved by a third author. The meta-analysis of prevalence provided estimated proportions, 95% confidence intervals, and measures of heterogeneity (I²). Based on I², the heterogeneity might be negligible (0–40%), moderate (30–60%), substantial (50–90%), and considerable (75–100%). The primary outcome was the incidence of AAA rupture. Secondary outcomes included the rate of small AAAs reaching the threshold for repair, aortic-related mortality, and all-cause mortality. Results: Fourteen publications (25,040 patients) were included in the analysis. The outcome rates of the small AAA group (55 mm) were 25.7% (95% CI 18.0–34.3; I² = 72.0%) of rupture, 22.1% (95% CI 16.5–28.3; I² = 25.0%) of aortic-related mortality, and 61.8% (95% CI 47.0–75.6; I² = 89.1%) of all-cause mortality. The sensitivity analysis demonstrated a higher rupture rate in studies including 72 years, >17% of female patients, and >44% of current smokers. Conclusion: The rarity of rupture and aortic-related mortality in small AAAs supports the current conservative management of small AAAs. Surveillance seems indicated, as one-fifth reached the threshold for repair. Large aneurysms had a high incidence of rupture and aortic-related mortality. However, these data seem biased by the sparse and heterogeneous literature overrepresented by patients unfit for surgery. Specific rupture risk stratified by age, gender, and fit-for-surgery patients with large AAAs needs to be further investigated.

Dual-energy computed tomography (DECT) can estimate tissue vascularity and perfusion via iodine quantification. The aim of this systematic review was to outline current and emerging clinical applications of iodine quantification within the gastrointestinal tract using DECT. The search was conducted with three databases: EMBASE, Pubmed and The Cochrane Library. This identified 449 studies after duplicate removal. From a total of 570 selected studies, 30 studies were enrolled for the systematic review. The studies were categorized into four main topics: gastric tumors (12 studies), colorectal tumors (8 studies), Crohn’s disease (4 studies) and miscellaneous applications (6 studies). Findings included a significant difference in iodine concentration (IC) measurements in perigastric fat between T1–3 vs. T4 stage gastric cancer, poorly and well differentiated gastric and colorectal cancer, responders vs. non-responders following chemo- or chemoradiotherapy treatment among cancer patients, and a positive correlation between IC and Crohn’s disease activity. In conclusion, iodine quantification with DECT may be used preoperatively in cancer imaging as well as for monitoring treatment response. Future studies are warranted to evaluate the capabilities and limitations of DECT in splanchnic flow.

Endovascular repair has become the primary treatment option for abdominal aortic aneurysms over the past decade. The favorable results as well as technical evolution have led endovascular repair to include fenestrated and branched technology for complex juxtarenal, suprarenal, and thoracoabdominal aneurysms. These grafts are, however, extensively customized and patient tailored at present precluding their use in emergency situations. Certain aspect of aneurysm anatomy also limits them. The chimney technique uses standard, off-the-shelf endovascular devices that extend the use of standard aortic stent grafts for aneurysms without suitable proximal landing zones particularly in acute situations. Early results are promising and warrant a continued development of the technique until such time that dedicated devices are available for the treatment of these complex aneurysms.