CTA, MRA, Angiography, Venography, IVUS, and Radiation Safety

8.1Choosing the imaging modality for the clinical question

The first decision is not which scanner is available, but what management question the image must answer. In lower-extremity arterial disease, the question may be diagnostic confirmation, hemodynamic localisation before intervention, full anatomic mapping for revascularization, or clarification of an inconclusive noninvasive study. For suspected symptomatic PAD requiring confirmation, duplex ultrasound is usually appropriate when local laboratory quality is reliable. For revascularization planning, CTA and MRA are usually appropriate and have comparable diagnostic roles in suitable patients. Catheter angiography should generally be reserved for an encounter in which intervention is planned or for a case in which noninvasive imaging does not resolve the clinical question. The request should therefore state the symptom pattern, physiologic abnormality, intended treatment decision, and why the selected modality is expected to change management. ACR Appropriateness Criteria 2022

For the vascular surgeon, modality selection should be documented as a clinical decision rather than a radiology order alone. A useful note records the indication, the territory to be imaged, the decision that will follow from the result, and the patient-specific modifiers: renal function, prior iodinated or gadolinium contrast exposure, previous stents or endografts, severe arterial calcification, claustrophobia or MR-device concerns, and cumulative radiation exposure. European PAD guidance similarly frames CTA, MRA, and DSA selection around renal function, prior contrast exposure, and prior interventions rather than treating the modalities as interchangeable. ESVS asymptomatic LEAD/IC guideline 2024

A simple and safe sequence for symptomatic lower-extremity disease is to begin with bedside assessment and physiologic testing, use duplex ultrasound when the question is confirmation or hemodynamic localisation, and proceed to CTA or MRA when a revascularization plan is being constructed. This approach avoids the common error of obtaining a beautiful anatomic study before confirming that the anatomy explains the patient’s symptoms, wounds, or hemodynamic deficit. The 2024 PAD guideline keeps advanced anatomic imaging in context with symptoms, pulse examination, wounds, risk status, and physiologic testing. ACC/AHA PAD guideline 2024

Duplex ultrasound remains a practical first-line anatomic-hemodynamic test when the laboratory can report reproducible velocities and waveforms. For lower-extremity arterial duplex, a peak systolic velocity ratio of at least 2.0 across a lesion is widely used to indicate at least 50% stenosis, and a ratio of at least 4.0 indicates at least 70% stenosis. A peak systolic velocity of at least 300 cm/s, particularly with monophasic distal waveforms, also supports a severe stenosis category. Absent or reversed flow supports occlusion. These thresholds must be interpreted with the patient’s haemodynamics, symptoms, and multilevel disease, because heavily calcified plaques and serial lesions can distort velocity-based grading. AUC peripheral vascular ultrasound 2012

CTA is commonly selected when the surgeon needs a broad anatomic map for revascularization planning, especially when inflow, outflow, access, prior interventions, and calcification must be understood in one examination. ACR appropriateness guidance rates CTA as usually appropriate for revascularization planning in adults with symptomatic PAD, but the same guidance emphasises that radiation exposure, iodinated contrast, renal function, and severe calcification can modify the choice. The order should specify that the study is for vascular planning, not simply “leg pain,” and the report should identify the anatomic segments relevant to the next decision. ACR Appropriateness Criteria 2022

MRA is a zero-ionising-radiation alternative for lower-extremity vascular imaging and is particularly attractive in young patients, patients requiring repeated imaging, and patients in whom radiation stewardship is a prominent concern. It is also endorsed for anatomic characterisation in patients with PAD being considered for revascularization. The surgeon must still check whether MR safety screening, implants, stents, motion, severe calcification, claustrophobia, or local image quality will limit its usefulness. Zero ionising radiation does not mean zero risk; it shifts the safety workflow from radiation and iodinated contrast to MR-environment and contrast-specific screening. ACC/AHA PAD guideline 2024 · ACR Manual 2024 · ACR Appropriateness Criteria 2022

Catheter angiography should be chosen deliberately. It remains powerful because it can combine diagnosis, hemodynamic judgment, and treatment in one session, but it carries procedural risk, operator-dependent radiation exposure, and contrast burden. For symptomatic PAD, ACR appropriateness guidance supports catheter angiography primarily when it is combined with planned intervention or when noninvasive imaging is inconclusive. A diagnostic-only angiogram after adequate CTA or MRA should be unusual and should be justified in the record. ACR Appropriateness Criteria 2022

In asymptomatic PAD, or stable intermittent claudication responding to medical and exercise therapy, routine anatomic imaging with CTA, MRA, or DSA is not appropriate. Imaging should be reserved for the patient in whom revascularization is contemplated, symptoms progress despite guideline-directed therapy, or another clinical question exists. This boundary is important: imaging can create a false sense that anatomy alone determines treatment, when the indication for intervention rests on symptoms, risk, physiology, and expected benefit. ESC 2017

Aortic imaging follows the same principle of matching the modality to the management question. The 2022 ACC/AHA aortic disease guideline is the current US reference point for thoracic and abdominal aortic imaging, while the 2010 thoracic aortic guideline is best viewed as legacy framing. For aortic disease, CT, MRI, and echocardiography measurements must use consistent anatomic landmarks, acquisition technique, and reporting so that interval growth and post-intervention change can be interpreted. ACC/AHA 2022 · AHA 2010

For AAA screening, abdominal duplex ultrasound is the standard initial modality because it avoids ionising radiation and has high diagnostic performance in the screening context. The USPSTF cites ultrasound sensitivity of 94–100% and specificity of 98–100% for AAA detection. USPSTF Abdominal Aortic 2019 CT or MR becomes relevant when ultrasound is limited by body habitus or bowel gas, when anatomy is complex, or when operative planning is needed.

Renal risk should be considered before CTA, catheter angiography, venography, or any other iodinated contrast examination, but renal risk should not be used reflexively to deny necessary imaging. KDIGO Stage 1 AKI is defined by a serum creatinine rise of at least 0.3 mg/dL within 48 hours, a rise to 1.5–1.9 times baseline within early follow-up window, or urine output below 0.5 mL/kg/h for 6–12 hours. KDIGO 2012 These thresholds give the surgeon concrete triggers for post-contrast monitoring in at-risk patients and for early review of volume status, haemodynamics, and nephrotoxic medications.

Radiation considerations should be explicit whenever CTA or fluoroscopy is chosen. Duplex ultrasound and MRA are zero-ionising-radiation modalities in lower-extremity vascular imaging, whereas CTA of the abdomen, pelvis, and lower extremities and catheter angiography fall into moderate-to-high relative radiation categories. ALARA-compatible modality choice, dose documentation, and protocol tailoring to patient size and indication should be part of routine vascular imaging practice, especially in young, female, and repeat-imaging patients. ACR Appropriateness Criteria 2022 · ACR Radiation Safety

AUC PVUS 2012 remains useful as a historical technical note for peripheral vascular ultrasound and selected IVUS appropriateness concepts, but it should not be read as current cross-society IVUS guidance. AUC peripheral vascular ultrasound 2012 Current modality selection in this chapter is anchored in the ACR and ACC/AHA recommendations above; adjunctive IVUS is handled separately in the intraprocedural section.

8.2CTA technique, runoff, and radiation/contrast tradeoffs

CTA is most useful when the surgeon needs a reproducible, comprehensive map that will alter treatment: access planning, lesion distribution, calcification, inflow and outflow assessment, relation to prior stents or bypasses, and the feasibility of endovascular or open reconstruction. For symptomatic PAD revascularization planning, ACR appropriateness guidance rates CTA as usually appropriate. The vascular request should state that the study is for revascularization planning and should identify the relevant territory, because a generic CT request may fail to answer the operative question. ACR Appropriateness Criteria 2022

The report should be structured around the planned decision. In a lower-extremity runoff study, the surgeon needs the inflow segment, treated or diseased iliac and femoropopliteal segments, tibial runoff, and any prior intervention described in a way that can be reconciled with symptoms, wounds, and physiologic testing. Severe calcification can reduce CTA confidence, and multilevel disease may require correlation with duplex or catheter angiography. When CTA findings and clinical physiology disagree, the discrepancy should be documented rather than ignored. ACC/AHA PAD guideline 2024 · ACR Appropriateness Criteria 2022

CTA is not a “free” planning test. ACR appropriateness materials classify CTA of the abdomen, pelvis, and lower extremities in a moderate-to-high relative radiation category. The practical implication is not to avoid CTA when it is the right test, but to justify it, tailor the protocol to the question, and document dose parameters such as dose-length product according to local practice. Repeat-imaging patients deserve particular attention, because cumulative exposure often accumulates through individually reasonable examinations. ACR Appropriateness Criteria 2022 · ACR radiation safety

Iodinated contrast planning should begin before the patient reaches the scanner. At-risk patients should have baseline renal function identified, hydration and nephrotoxic medication issues reviewed, and the expected contrast burden weighed against the clinical need. KDIGO Stage 1 AKI provides concrete post-exposure triggers: a creatinine rise of at least 0.3 mg/dL within 48 hours, a rise to 1.5–1.9 times baseline within early follow-up window, or urine output below 0.5 mL/kg/h for 6–12 hours. KDIGO 2012 In practice, the surgeon should know which patients require post-CTA creatinine follow-up and which patients need a preprocedural renal-protection plan.

Patients with eGFR below 30 mL/min/1.73 m² sit in the highest-risk band for contrast-associated AKI strategies and require an individualised plan: whether the study is urgent, whether a non-iodinated alternative can answer the question, whether contrast volume can be minimized, whether isotonic crystalloid hydration is appropriate, and whether nephrology input is needed. Patients with eGFR 30–44 mL/min/1.73 m² require risk-adapted hydration and review of nephrotoxic co-medications. The decision should not be reduced to a single cutoff; withholding indicated imaging can also harm the patient. KDIGO 2012

Contrast safety is broader than kidney injury. The ACR contrast manual frames contrast administration around patient selection, preparation, injection practice, allergic-like and physiologic reactions, kidney injury terminology, gadolinium considerations, pregnancy and breastfeeding, and reaction treatment workflows. ACR Manual 2025 · ACR Manual A safe CTA service therefore needs a pre-exam risk assessment and a reaction-response system, not merely a creatinine checkbox.

CTA for aortic disease requires special attention to reproducible measurements. The 2022 ACC/AHA aortic disease guideline links diagnosis and surveillance to consistent anatomic landmarks, acquisition technique, and reporting across CT, MRI, and echocardiography. This is particularly important when a later decision will depend on interval growth or post-repair change. The surgeon should expect the report to identify where the measurement was made and how it was made, so that a future comparison is meaningful. ACC/AHA 2022

CTA is often the preoperative reference point in AAA and aorto-iliac aneurysm planning, but surveillance intervals and repair thresholds belong to disease-specific management pathways. In this chapter, the key imaging principle is that the same modality must answer different questions at different moments: screening ultrasound identifies the aneurysm, surveillance establishes change over time, and preoperative CTA defines anatomy for intervention. SVS and ESVS AAA guidelines provide the US and European imaging frames for screening, surveillance, and preoperative planning. Editor's Choice European 2024 · SVS 2018

The long-term need for post-EVAR imaging should be understood even when this chapter does not reproduce detailed surveillance schedules. EVAR-1 15-year follow-up reported late endovascular versus open AAA repair outcomes including late reintervention and rupture signals, supporting continued attention to late post-EVAR imaging beyond the early postoperative years. Endovascular versus open 2016 When the patient returns years after EVAR, the imaging question is not merely whether the graft is present, but whether late findings change rupture risk, reintervention planning, or the need for closer aortic follow-up.

IVUS should not be used as a substitute for CTA when noninvasive imaging can define the anatomy before an elective intervention. Its value is adjunctive and procedural: sizing during EVAR or TEVAR, troubleshooting equivocal angiography, evaluating dissection extent, and assessing post-stent or endograft apposition. Routine diagnostic-only IVUS without procedural impact is rarely appropriate, whereas IVUS that changes sizing, landing-zone confidence, or post-deployment correction can be highly useful. AUC peripheral vascular ultrasound 2012

8.3MRA, duplex, IVUS, venography, and catheter angiography roles

MRA occupies the space between duplex and CTA: it can provide anatomic characterisation for revascularization planning without ionising radiation, but it requires MR-environment safety screening and is vulnerable to artefacts and patient tolerance issues. For PAD patients being considered for revascularization, the 2024 ACC/AHA PAD guideline endorses MRA for anatomic characterisation, and ACR appropriateness guidance rates MRA as usually appropriate with diagnostic performance comparable to CTA in suitable patients. ACC/AHA PAD guideline 2024 · ACR Appropriateness Criteria 2022

MR safety is a workflow, not a final question asked at the scanner door. The ACR MR safety manual organises risk control around MR personnel roles, screening and gowning, final safety checks, implants and devices, special populations, zone-based environments, and hazards from static magnetic fields, gradients, and radiofrequency exposure. ACR Manual 2024 · ACR Manual 2024 A vascular MRA order should therefore trigger implant and device review early enough to prevent cancellation, unsafe entry into the MR environment, or selection of a modality that cannot be completed.

Duplex ultrasound is most valuable when it combines anatomy, haemodynamics, and local expertise. For lower-extremity arterial disease, it can confirm disease, localise haemodynamically important lesions, and support pre-intervention planning. The 2024 PAD guideline endorses duplex ultrasound for hemodynamic and anatomic localisation before intervention when revascularization is contemplated. The surgeon should not accept a report that lists only “stenosis present” when management depends on velocity, velocity ratio, waveform, segment, and physiologic correlation. ACC/AHA PAD guideline 2024 · AUC peripheral vascular ultrasound 2012

Velocity thresholds provide a shared language between the laboratory and surgeon. A PSVR of at least 2.0 supports at least 50% stenosis, and a PSVR of at least 4.0 supports at least 70% stenosis; a PSV of at least 300 cm/s with monophasic distal waveforms also supports severe stenosis. These values are not independent of context. Calcification, tandem stenoses, inflow disease, and lab-specific validation can alter confidence, so a severe duplex label should be reconciled with symptoms, ABI or other physiologic testing, wounds, and the proposed intervention. AUC peripheral vascular ultrasound 2012

Catheter angiography is best treated as a diagnostic-therapeutic platform. Its strongest role is the patient in whom endovascular intervention is planned or the patient whose noninvasive imaging remains inconclusive despite an important clinical question. It should be scheduled with a clear endpoint: proceed to treatment if anatomy and risk are favorable, clarify a discrepancy, or obtain information not available from CTA, MRA, or duplex. ACR Appropriateness Criteria 2022

The radiation burden of catheter angiography is operator-dependent. ACR appropriateness materials classify catheter angiography in a moderate-to-high relative radiation category and note that fluoroscopy time and technique materially influence cumulative dose. The operative note should include dose-related parameters used by the institution, such as fluoroscopy time and dose-area product, and the operator should actively minimise dose through ALARA practice rather than relying on default machine settings. ACR Appropriateness Criteria 2022 · ACR Radiation Safety

Venography should be selected with the same discipline used for arterial catheter angiography. When iodinated contrast venography is performed, the patient is exposed to contrast-related risks and, when fluoroscopy is used, ionising radiation. The indication should therefore be a venous anatomic or procedural question that will change management, and the pre-exam process should include contrast reaction readiness, renal-risk assessment where relevant, and documentation of dose parameters according to local practice. Preface Executive Summary 2007 · ACR Manual

IVUS is most useful when the angiographic lumen image is insufficient for the decision at hand. During peripheral or aortic interventions, IVUS is usually appropriate for equivocal angiographic findings, sizing in EVAR or TEVAR, evaluating aortic dissection extent, and assessing post-stent or endograft apposition. Examples of practical questions include whether a wire is in the true lumen, whether a dissection flap extends into a branch-vessel origin, whether a deployed stent is underexpanded, and whether angiography has underestimated plaque burden. AUC peripheral vascular ultrasound 2012

IVUS has boundaries. It adds procedural time, cost, and device manipulation; its benefit depends on operator experience, anatomy, and whether the information will change treatment. It does not replace CTA or MRA for global preoperative anatomic characterisation, and it should not be used as a routine diagnostic-only test when noninvasive imaging can answer the question. The surgeon should document the reason IVUS was used and the action taken because of it. AUC peripheral vascular ultrasound 2012

Carotid and cerebrovascular imaging pathways also illustrate the changing role of catheter angiography. In CREST, catheter angiography served as a comparator imaging modality within a major carotid revascularization trial, but modern practice increasingly uses noninvasive imaging to define anatomy and risk before deciding whether an invasive procedure is necessary. Stenting versus Endarterectomy 2010 Outcome interpretation for carotid intervention belongs elsewhere; the imaging lesson is that catheter angiography should be reserved for cases in which its procedural information or therapeutic capability is needed.

AAA screening demonstrates the opposite end of the invasiveness spectrum. MASS showed the population value of ultrasound screening in men aged 65–74, and USPSTF guidance cites high sensitivity and specificity for ultrasound AAA detection. USPSTF Abdominal Aortic 2019 · AAA 2002 For the surgeon, this reinforces that the lowest-risk modality that answers the clinical question should be used first; cross-sectional imaging is then reserved for complexity, limited ultrasound quality, or operative planning.

8.4Imaging for intervention planning and intraoperative decision-making

Intervention planning starts with a defined indication. The surgeon should be able to state why the patient is being considered for revascularization, which symptoms or wounds are being treated, what physiologic abnormality supports the plan, and what anatomic information is still needed. The 2024 PAD guideline places advanced anatomic imaging in the context of bedside findings and physiologic testing, and ACR appropriateness guidance separates diagnostic confirmation from revascularization planning. ACC/AHA PAD guideline 2024 · ACR Appropriateness Criteria 2022

For symptomatic lower-extremity PAD in which revascularization is being planned, CTA or MRA is appropriate first-line anatomic imaging in most suitable patients. The practical choice depends on renal function, radiation concerns, prior interventions, stent artefact, calcification, MR safety, patient tolerance, and local image quality. European guidance similarly supports CTA or MRA as first-line anatomic modalities for symptomatic LE-PAD revascularization planning, with DSA primarily linked to planned endovascular intervention rather than diagnosis alone. ACC/AHA PAD guideline 2024 · ESVS asymptomatic LEAD/IC guideline 2024

Duplex can be sufficient for selected pre-intervention decisions when the lesion is well localized, the laboratory is reliable, and the result matches the clinical picture. It is particularly helpful for hemodynamic localisation, for reconciling symptoms with segmental disease, and for avoiding unnecessary cross-sectional imaging in patients who are not yet candidates for intervention. When the duplex result is the basis for intervention, the report should include PSV, PSVR, waveform, segment, and limitations. ACC/AHA PAD guideline 2024 · AUC peripheral vascular ultrasound 2012

CTA is often preferred when the surgeon needs a broad map that includes access, inflow, outflow, prior devices, and calcification. It is endorsed for anatomic characterisation in PAD patients considered for revascularization, but the surgeon must reconcile its strengths with renal function and radiation exposure. Severe calcification can degrade CTA interpretation, and a CTA that cannot confidently define a target or landing zone may need MRA, duplex correlation, IVUS during intervention, or catheter angiography. ACC/AHA PAD guideline 2024 · ACR Appropriateness Criteria 2022

MRA is most useful when radiation avoidance or iodinated contrast avoidance is important and MR safety screening is favorable. It is usually appropriate for revascularization planning and is endorsed for anatomic characterisation in PAD patients being considered for revascularization. Its limitations should be anticipated before scheduling: stent artefact, motion, severe calcification, claustrophobia, device restrictions, and local technical expertise can all determine whether it will answer the operative question. ACC/AHA PAD guideline 2024 · ACR Manual 2024 · ACR Appropriateness Criteria 2022

DSA should be planned as a therapeutic encounter whenever possible. In a patient with symptomatic disease and adequate noninvasive planning, the angiogram should begin with a treatment strategy, equipment plan, access plan, renal-risk plan, and radiation-minimisation plan. If the angiographic findings differ from CTA, MRA, or duplex, the operator should identify whether the discrepancy reflects calcification, flow state, projection, stent artefact, or progression, and should document how the intraoperative finding changed management. ESVS asymptomatic LEAD/IC guideline 2024 · ACR Appropriateness Criteria 2022

Renal risk is an intraoperative issue as much as a preoperative issue. In patients with eGFR below 30 mL/min/1.73 m², the contrast strategy should be individualised before the case begins, including whether alternative imaging can answer part of the question, how contrast volume will be minimized, whether isotonic crystalloid hydration is appropriate, and whether nephrology input is needed. In the eGFR 30–44 mL/min/1.73 m² band, hydration and medication review should be risk-adapted. Post-procedure monitoring should use KDIGO AKI criteria rather than vague concern about “renal bump.” KDIGO 2012

Radiation safety also belongs in the operative plan. Before fluoroscopy, the team should anticipate case complexity, access route, expected imaging angles, and whether IVUS or prior CTA/MRA can reduce fluoroscopy. During the case, fluoroscopy time and dose-area product should be monitored, and after the case, dose-related parameters should be documented. ALARA is not an abstract principle; it is a series of operator choices made throughout the case. ACR Appropriateness Criteria 2022 · ACR Radiation Safety · Preface Executive Summary 2007

IVUS can change intraoperative decision-making when angiography is ambiguous or incomplete. It is usually appropriate for EVAR and TEVAR sizing, for evaluating the extent of aortic dissection, for troubleshooting equivocal angiographic findings, and for confirming post-stent apposition. In aortic dissection, IVUS may help define true-lumen position, dissection extent, and branch-vessel involvement during endovascular evaluation, but it does not replace CTA for global preoperative anatomy. AUC peripheral vascular ultrasound 2012

Stable intermittent claudication that responds to medical and exercise therapy should not be escalated to anatomic imaging simply because stenoses are suspected. Imaging becomes appropriate when symptoms progress, functional limitation remains unacceptable despite therapy, or revascularization is being contemplated. This protects patients from contrast, radiation, incidental findings, and procedures that do not address a meaningful clinical endpoint. ESC 2017

Aortic intervention planning requires the same discipline of asking which imaging finding changes treatment. Screening ultrasound, surveillance ultrasound, preoperative CTA, intraoperative angiography, and IVUS each answer different questions. SVS and ESVS AAA guidelines provide the imaging framework for AAA screening, surveillance, and preoperative planning, while UKSAT and MASS provide trial-level context for size-driven surveillance and screening ultrasound. Editor's Choice European 2024 · SVS 2018 · AAA 2002 · Mortality results randomised 1998

8.5Reporting quality, safety, and follow-up boundaries

A vascular imaging report should help the next clinician act safely. It should identify the indication, modality, relevant territory, prior interventions, key measurements, hemodynamic correlates when applicable, limitations, and comparison with prior imaging. For aortic imaging, consistent landmarks and acquisition technique are essential because future decisions may depend on interval change rather than a single diameter. ACC/AHA 2022

For thoracic aortic CTA or MRA surveillance, reporting should use standardized measurement technique. The 2022 ACC/AHA aortic disease imaging specifications define thoracic aortic dilation at 4.0 cm and aneurysm at 4.5 cm based on dissection-risk analyses, and recommend inner-edge-to-inner-edge ECG-synchronised CTA or MRA measurement, with outer-edge measurement when wall abnormalities are present. ACC/AHA 2022 Growth thresholds also matter: growth of at least 0.5 cm/year in sporadic disease or at least 0.3 cm/year in heritable disease should trigger consideration in the appropriate clinical context.

Follow-up recommendations should stay within the report’s competence and the chapter’s boundaries. It is appropriate to state that a finding requires comparison, closer surveillance, disease-specific management review, or operative planning. It is not useful to copy broad surveillance schedules into every report when those schedules depend on disease type, size, symptoms, repair status, and local protocols. The surgeon’s responsibility is to ensure that imaging findings likely to change treatment are not buried in descriptive text. Editor's Choice European 2024 · ACC/AHA 2022 · SVS 2018

For lower-extremity duplex, reporting quality depends on reproducible thresholds and transparent caveats. A PSVR of at least 2.0 supports at least 50% stenosis, and a PSVR of at least 4.0 or PSV of at least 300 cm/s with monophasic distal waveforms supports at least 70% stenosis. The report should state when calcification, poor acoustic windows, inflow disease, or multilevel disease limits confidence. A surgeon should be cautious about planning intervention from a duplex report that omits velocity ratios, waveforms, or the level of uncertainty. AUC peripheral vascular ultrasound 2012

For asymptomatic PAD and stable intermittent claudication responding to therapy, the safest follow-up boundary is not more anatomy; it is continued clinical and risk-factor management unless symptoms change or revascularization is being considered. European PAD guidance recommends against routine anatomic imaging in asymptomatic PAD or simple intermittent claudication that responds to medical and exercise therapy. ESC 2017 Imaging escalation should be linked to a decision point, not curiosity.

Contrast safety documentation should include more than renal function. The ACR contrast manual frames contrast practice around patient selection, preparation, injection, allergic-like and physiologic reactions, kidney injury terminology, gadolinium and NSF risk, pregnancy and breastfeeding, and treatment of reactions. ACR Manual 2025 · ACR Manual In vascular practice, this means that a CTA, catheter angiogram, venogram, or contrast-enhanced MRA should be preceded by a risk assessment and supported by a response plan for acute reactions.

Post-contrast renal follow-up should use defined AKI thresholds. KDIGO Stage 1 AKI is present with a creatinine rise of at least 0.3 mg/dL within 48 hours, a rise to 1.5–1.9 times baseline within early follow-up window, or urine output below 0.5 mL/kg/h for 6–12 hours. KDIGO 2012 In patients with eGFR 30–44 mL/min/1.73 m², risk-adapted isotonic crystalloid hydration and review of nephrotoxic medications should be considered; in patients below 30 mL/min/1.73 m², the contrast plan should be individualised.

MR safety documentation should confirm that the MR environment has been treated as a controlled clinical space. Screening, gowning, final checks, implant and device review, staff roles, special-population considerations, and zone-based access are all part of safe vascular MRA. The report does not need to reproduce the entire safety workflow, but the service must have completed it before acquisition. ACR Manual 2024 · ACR Manual 2024

Radiation reporting should make exposure visible. For CTA, dose-length product or the institution’s accepted dose metric should be available; for fluoroscopy-guided angiography or venography, fluoroscopy time and dose-area product should be documented according to local standards. The ACR radiation safety resources provide operational support for dose estimates, diagnostic reference levels, achievable doses, fluoroscopy management, equipment quality control, occupational monitoring, and ALARA implementation, while ICRP Publication 103 supplies the international radiation-protection framework for effective dose and dose-limit categories. ACR Radiation Safety · Preface Executive Summary 2007

After EVAR or other endovascular repair, late imaging abnormalities should be interpreted as potential planning events, not administrative surveillance chores. EVAR-1 15-year follow-up provides the long-term rationale for vigilance by documenting late outcome signals after endovascular AAA repair, including reintervention and rupture concerns. Endovascular versus open 2016 When late imaging suggests device-related failure, sac-related concern, or anatomy requiring reintervention, the escalation should be explicit and directed to an aortic management pathway.

The final responsibility of the vascular surgeon is to close the loop. The imaging result should be matched back to the original question: Does the patient need no anatomic intervention, further noninvasive clarification, catheter angiography with possible treatment, renal-risk mitigation before contrast, MR safety review, or disease-specific surveillance? A technically adequate image that does not answer the clinical question is not an adequate vascular imaging episode. ACC/AHA PAD guideline 2024 · ACR Appropriateness Criteria 2022

For thoracic aortic reporting, the 2022 ACC/AHA aortic disease guideline defines 4.0 cm dilation and 4.5 cm aneurysm thresholds and specifies reproducible CTA/MRA measurement technique. ACC/AHA 2022 Those values are preserved here as an ACC/AHA-scoped note, not as a cross-society threshold comparison. The older thoracic-aorta guideline is not used as a modern alignment partner.