CTA or MRA for PVD Screening: Advantages and Limitations of Both Michael H. Wholey, MD, MBA Interventional Radiology Christus Santa Rosa San Antonio, TX Monday Feb 6, 2012 8:10-8:20 AM

Michael H. Wholey, MD Consulting Fees: Covidien My presentation will include off-label discussions: Carotid stents and embolic protection are off-label.

CTA or MRA for PVD Screening: Advantages and Limitations Financial Responsibilities Consultant: Covidien Boston Scientific Founder: Wholey and Wholey, LLC

Peripheral Vascular Disease: Screening Tests Non-Invasive Diagnostic Tests Ankle Brachial Index (ABI) Arterial Color Doppler (Duplex) Ultrasound Arterial Segmental Pressures Arterial Pressure Volumes (PVR) CTA MRA Angiography The Judgment of Paris, Peter Paul Rubens,

Lower Extremity: Epidemic

Symptoms of PAD Critical Limb Ischemia Asymptomatic Claudication Acute Limb Ischemia Amputation -Rest Pain -Tissue Loss ---Ulceration ---Gangrene

Benefits of CTA/MRA Assessment of Incidental Findings Awareness of significant vascular findings Pre-planning for intervention Major decisions in patient management

CTA or MRA Scan Lower Extremities Should be used as a screen for patients with abnormal ABI, Segmental Pressures and/or Physical Exam.

Another View for Lower Extremity Intervention F/U: Patients presenting with CLAUDICATION American College of Radiology ACR Appropriateness Criteria®

MRA for PAD Benefits: No Radiation Less Nephrotoxicity Easy to read and manipulate images Do not have problems caused with calcium artifacts

MRA Lower Extremities: Bolus Chasing Bolus-chasing method material in which vessels are imaged sequentially as contrast flows distally. Multiple overlapping fields of view are used, and images are obtained in the coronal or sagital planes (usually in 3 coronal stations). This technique also uses subtraction to improve the resultant vascular images by suppressing the background and reducing the volume averaging. -Occluded Left SFA -Diseased Bilateral Post Tibials

MRA Bolus Chasing Bolus-chasing MRA is rapidly evolving Technology revolution that made equipment widely available, Improvements in technical capabilities (eg, increased field strengths, dedicated coils, increased SNRs, decreased repetition times, improved bolus-detection techniques, MR SmartPrep technique)

MRA vs DSA in runoff vessels 2D TOF method with extremity coil ACR Rapid technology assessment Baum et al JAMA 1995; 274:875 Multicenter trial (n=155 pts) MRA distinguishes patent segments Sensitivity MRA 85% DSA 83% Specificity MRA 81% DSA 81% MRA changed treatment plans 13%

MRA for PAD: Disadvantages -Contraindications: Implanted pacemakers Defibrillators Surgical aneurysm clips Renal Dysfunction -Difficulties in Interpretation MRA also takes longer to perform than a CT angiogram More Expensive Requires multiple segments Difficulties in Performing Limited on visualization of small vessels Overestimation of stenosis Metal stents Disrupt the MRA images.

Try to order an MRI on a Patient with elevated creatinine ? FDA describes the risk for NSF following exposure to a GBCA in patients with acute or chronic severe renal insufficiency (glomerular filtration rate <30 mL/min/1.73 square meters) and patients with acute renal insufficiency of any severity due to the hepato-renal syndrome

CTA: Ability to see whole body Guidewire exited the right common iliac and caused Type B Dissection

Aortic Occlusion What would you do with this renal artery ? Aorta occluded just inferior to left renal artery which has high grade stenosis.

CTA: Pelvic Pathology Persistent Femoral Sciatic Artery -35 yr old pt s/p PTCA with claudication -Allows quick overview of multiple diseased segments -Allows for intervention planning

CTA: Femoral Disease Closure device complication in diseased cfa

CTA Lower Extremities History: -Patient with SFA stent placed one year ago. -Patient returning with increased claudication of the right leg. Arterial Segmental pressures with decreased waveform right leg. Intervention: -Findings: in-stent restenosis of the stent -Treatment: plan on PTA or removing plaque.

Information obtained from CTA Pt with pulsatile mass behind knee -Embolization performed afterwards Pt with large mass left groin and hx fem-fem graft -Large pseudoaneurysm

Benefits of Infrapopliteal CTA CTA Shows moderate peroneal disease but severe anterior tibial Based upon CTA findings , able to see anterior tibial, cross and PTA the vessel

CTA Benefits and Drawbacks? CTA (Abdomen, Pelvis, Bilateral Lower Legs) Able to rotate with axial, coronal and sagital images easily Able to scan larger segments Easier to schedule Able to see surrounding pathology Drawbacks Artifacts from calcium No measure of flow

Benefits of CTA/MRA Assessment of Incidental Findings Incidental Renal Cell Carcinoma found on routine CTA Abdomen in two pts

Pitfalls of CTA A major pitfall is that although imaging vessel calcification is an advantage of CT, beam hardening artifacts remain difficulties, especially dense medial calcifications found in diabetic patients. What is the degree of stenosis: 60% 70% 80% or 90%

Simple Technologies Available Effective Follow Up Good Clinic Personnel Home Health Care Podiatry Visits Skype/JPEGS Pt in remote clinic following recent catheterization. Distal Embolization

Conclusions Screening for PAD: -Obtain Non invasive Arterial Duplex or Segmental Pressures first, if abnormal -Obtain CTA or MRA Very similar in results compared to DSA Useful to see immediate disease Help to plan intervention Replacing diagnostic angiograms

Conclusions Future is very bright for CTA/MRA