Modern cross-sectional imaging sweeps past the abdominal aorta in each abdominopelvic scan. In a 2024 to 25 New Zealand cohort of routine abdominopelvic CT scans, 5.2% of adults ≥50 years harbored an unsuspected AAA, while 4.4 % of lumbar‐spine MRI scans contained an aneurysm. Incidental imaging now uncovers more AAAs each year than dedicated screening programs in several Western countries.

Recent U.S. cost analyses indicate that steering an incidentally-detected AAA into elective surveillance and repair now spares patients the 65% to 85% mortality that accompanies rupture and avoids some $80,000 in extra hospital expenditure for an acute abdominal aortic syndrome (elective repairs average $43,000–50,000, whereas an emergency ruptured repair is ≈$124,000).

However, this opportunity is often squandered at the reporting desk. In the aforementioned spine-MRI series, radiologists noted the aneurysm in only 31% of cases, leaving two-thirds undocumented to referring clinician. Similar patterns persist for CT: earlier multi-institution audits showed roughly one-third of new AAAs were never documented in the report, while a 2021 Portuguese registry confirmed that even when documented, follow-up orders were absent in 36%. Such oversights may translate directly into harm. A Norwegian rupture registry reported in 2024 that 39% of patients who later presented with a catastrophic rupture actually had an aneurysm incidentally-recognized on imaging months or years before but were not followed.

Real-world studies show feasibility and potential value. An NIH-Wisconsin deep-learning model detected AAAs on 9,172 CT colonography studies with 96% sensitivity/specificity, all without radiologist input. A commercial artificial intelligence (AI) tool at Yale reanalyzed >4,000 emergency CTs, boosting true-positive detection by 7.4% and recovering 5 silent AAAs missed in original reports. In a real-world implementation, an AI-assisted detection-and-care protocol increased the proportion of patients receiving initial AAA evaluation and longitudinal follow-up, shortened time to first evaluation, and reduced the interval from detection to repair. Taken together, and consistent with recent reviews on AI for aortic disease, opportunistic, automation-assisted AAA detection could be aligned with value-based care. Detailed size-stratified surveillance intervals are summarized in Table 1 .

Major guidelines for AAA screening converge on a 1-time abdominal ultrasound for men aged 65 to 75 years who have ever smoked and recommend selective screening of older women or first-degree relatives when local prevalence exceeds 1%. ^,, Medicare has covered this examination since 2007, and the United States Preventive Services Task Force (USPSTF) still assigns it a “B” grade, citing moderate certainty of substantial net benefit. ^, At approximately $95 under the 2024 Medicare Outpatient Prospective Payment System, it represents the lowest-cost gateway to rupture prevention. Screening eligibility criteria and recommended modality are outlined in Table 2 .

A 2019 USPSTF evidence report pooling 4 randomized trials (124,929 participants) showed a 35 % relative reduction in AAA mortality over 13 to 15 years among invitees, about 1 rupture death averted per 240 men screened. Cost-utility models based on U.S. life tables place the incremental cost-effectiveness ratio of 1-time ultrasound near $7,000 to 14,000 per quality-adjusted life-year, well below conventional willingness-to-pay thresholds. Real-world accounting supports this: a Veterans Affairs (VA) program that funneled screen-detected AAAs into elective care saved roughly. $18,000 per patient relative to the rupturefirst status quo because emergency repairs remain more than twice as costly. In our value based framework, Porter’s value is outcomes across the AAA care cycle divided by total episode cost, and opportunistic CT based screening increases value by improving rupture free survival and related outcomes while adding only a small increment to cost.

Despite these advantages, screening uptake remains strikingly low and unequal. In a large academic health system, only 6.9% of newly eligible 65-year-old men were screened within 1 year, with Black patients 27% less likely to be screened than White peers. Among privately insured adults, just 38.7% of USPSTF-eligible patients received screening, and living outside metropolitan areas independently reduced the odds of screening. Women, who already face higher rupture case-fatality, are rarely screened even when eligible under broader Society for Vascular Surgery (SVS) criteria. ^, Women with untreated AAAs face a higher risk of rupture than men, even at smaller diameters. This sex-based disparity is reflected in current guidelines, which recommend a lower diameter threshold for elective repair in women (5.0 cm vs 5.5 cm in men), citing higher rupture rates at comparable sizes. European guidelines similarly highlight that women have a markedly greater rupture hazard during surveillance and advocate earlier intervention. In U.S. population data, Black and Hispanic patients are more likely to present with ruptured rather than elective AAA, indicating a greater burden of untreated rupture in these groups. These access gaps further align with outcomes: in Medicarelinked data after elective EVAR, 5-year rupture was highest in Black women (6.4%) and lowest in White men (2.3%), with higher adjusted hazards of rupture and mortality in several female subgroups.

As an AAA nears the repair threshold, imaging priorities shift from interval surveillance to detailed operative mapping. Duplex ultrasound remains the cornerstone for serial diameter measurements because it is inexpensive, radiation-free, and highly sensitive; however, it cannot provide the anatomic detail required for procedural planning. Once an aneurysm approaches the actionable size or exhibits rapid growth, major guidelines recommend transitioning to advanced cross-sectional imaging. Current guidelines focus on the importance of thorough cross sectional preoperative imaging.

CT angiography (CTA) is the gold standard at this stage, offering high-resolution 3D visualization of the aneurysm’s true maximal diameter, shape, and relationship to renal and iliac arteries. One contrast-enhanced CTA spanning the thoracoabdominal aorta and ilio-femoral runoff delineates seal zones, branch involvement, and conduit caliber; additional scans seldom alter management yet add cost and ≈10 mSv of radiation per scan.

MR angiography (MRA) is a radiation-free alternative that provides comparable anatomic detail to CTA. MRA is especially useful for patients with contraindications to iodinated contrast. However, MRA comes with tradeoffs: it is more costly, less accessible, and longer in exam time, and metallic stent grafts can cause artifacts. ^,

In practice, CTA remains the first choice for preoperative imaging in most patients, with MRA reserved for specific situations. Recommended follow-up intervals for unrepaired AAAs are presented in Table 3 .

Economic considerations and imaging value. preoperative imaging choices carry measurable cost consequences. In contemporary U.S. data, each duplex ultrasound costs a mean $309, whereas an abdominal CTA costs $453. Because small AAAs may be monitored for years, such a cost differential accumulates when examinations are repeated every 6 to 12 months, making an ultrasound-first surveillance strategy, and reserving cross-sectional imaging for the point of intervention, the most cost-efficient pathway for small AAAs.

Bundled-payment signals. Payers are beginning to associate these value-based considerations with reimbursement. Centers for Medicare and Medicaid Services (CMS) forthcoming Transforming Episode Accountability Model (TEAM) places vascular surgical episodes, including AAA repair, under a single 30-day bundle that explicitly folds preoperative imaging into the episode price. ^, Under the Hospital Outpatient Prospective Payment System, any additional CT or MR study is folded into the Ambulatory Payment Classification for the primary service, so Medicare makes no separate payment for that extra scan, effectively eliminating the financial incentive for duplicative imaging.

For postprocedural follow-up, guidelines converge on a risk-stratified algorithm. For the majority of cases, a contrast-enhanced CTA at ∼30 days is recommended to confirm exclusion and device integrity. ^, If low-risk on that initial study (no endoleak, anatomy within instructions for use (IFU), adequate component overlap, and ≥10 mm proximal/distal apposition) duplex ultrasonography (DUS) ± contrast-enhanced ultrasound (CEUS) can be used for routine surveillance through years 1 to 4, with cross-sectional imaging reassessment at ∼5 years. Guidelines recommend earlier escalation to CTA/MRA for sac growth ≥5 mm, type I/III endoleak (or persistent type II with sac growth), device migration/compromised seal, or new symptoms. ^, Of note, this approach applies to standard EVAR. In contrast, complex repairs (fenestrated/branched/chimney) or higher-risk anatomies warrant individualized follow-up often with greater intensity. However, in real-world experiences imaging strategies vary. In an analysis of a national VA cohort of 27,792 EVAR patients (2000–2023), > 50 % of annual follow-up studies were still CT-based despite ultrasound being guideline-concordant for most. Likely drivers include legacy “annual CT” paradigms and default order sets, variable DUS access and operator-dependence, and concern for missed type I/III endoleaks or limited acoustic windows. Similarly, CT-heavy follow-up and underuse of ultrasound have been reported in Medicare and multicenter cohorts, with more aggressive annual cross-sectional surveillance not reducing aneurysm-related mortality versus risk-adapted follow-up. ^,,,

The cost and radiation penalty is substantial. A multi-institution analysis showed mean per-study costs of $2,132 for CTA vs $234 for DUS, and modeling demonstrated that switching just 50% of second-year scans to ultrasound would trim annual surveillance spending by 14% to 48%. When CT is required, converting triphasic protocols to single-phase dual-energy CT (DECT) or using photon-counting CT (PCD-CT) can reduce per-scan radiation dose by ∼30% to 60 % without sacrificing endoleak detection. ^, Even with dose-sparing CT, cumulative exposure matters: applying standard radiation-risk models to infrarenal EVAR surveillance suggests a 70-year-old man undergoing serial CTA accrues an excess lifetime cancer risk of roughly 0.4% to 0.6% (≈1 in 170–240). Because radiation models assign higher risk per dose to women of the same age, the corresponding excess risk is proportionally higher, reinforcing ultrasound-lean follow-up when clinically safe. ^,

In contrast, open surgical repair (OSR) requires far leaner follow-up. Both the 2024 European Society for Vascular Surgery (ESVS) guideline and contemporary SVS recommendations advise only (1) a single baseline cross-sectional study within 30 to 90 days to document graft patency and (2) one additional check at 5 years, with interim imaging triggered solely by new symptoms or sac enlargement >10 mm. Real-world data echo that policy: fewer than 20% of OSR patients undergo any abdominal imaging beyond year 2, yet late graft-related complications remain rare (<2 %) and reintervention rates are a fraction of those after EVAR. ^,

Even with liberal CT use, many patients fall off the imaging schedule altogether. In the same VA series, postEVAR follow up imaging adherence fell from 90% in year 1 to 58% by year 4, with lapses concentrated among unmarried veterans and those from racial-minority or rural areas, 29 of the 49 participating hospitals (59%) were classified as rural or nonmetropolitan, based on VA facility designations. Parallel Medicare data (9,695 beneficiaries, median follow-up 6.1 years) show only 43% maintained complete surveillance ( defined as ≥1 abdominal study every 15 months) with the greatest attrition after year 3. A contemporary commercial-claims analysis echoes these gaps, linking missed imaging to emergency readmissions and higher rupturerelated costs, particularly in socio-economically disadvantaged groups. These findings echo the observation that overimaging in some patients coexists with underimaging in others.

Evidence supporting an ultrasound-dominant strategy continues to build. A 2024 multicenter study of 1,012 EVAR patients followed with DUS-only after the first postoperative year reported 97 % freedom from AAA-related reintervention at 5 years, with no ruptures attributed to missed endoleaks. CEUS further boosts sensitivity, achieving 92% sensitivity and 98% specificity for endoleak classification, matching CTA while avoiding radiation and nephrotoxic contrast. Technology may soon close the residual accuracy gap: a 2024 deep-learning model applied to noncontrast CT detected clinically significant endoleaks with an AUC = 0.95 and >87% sensitivity, offering a pathway to low-dose, single-phase surveillance when cross-sectional imaging is required. Meta-analysis of dual-energy CT protocols shows comparable accuracy to triphasic CTA but at 30% to 40% lower radiation dose, reinforcing the trend toward leaner imaging. postprocedural imaging schedules for EVAR and OSR are consolidated in Table 4 .

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