Tips and Tricks to Utilize Noninvasive Imaging With US/CTA/MRA In Intervention

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1 Tips and Tricks to Utilize Noninvasive Imaging With US/CTA/MRA In Intervention Terry R. Bowers MD, FACC, FSVM Director, Vascular Medicine, William Beaumont Hospitals

2 Noninvasive Peripheral Imaging Duplex Ultrasound Inexpensive Readily available in lab and office Approved for screening Correlates well with disease severity in quartiles No adverse effects Computed Tomographic Angiography (CTA) Advantages Testing time short Excellent spatial resolution and characterization of disease severity Readily available 3D reconstruction Disadvantages Requires iodinated contrast Radiation exposure Challenging in calcified vessels

3 Noninvasive Peripheral Imaging Magnetic Resonance Angiography (MRA) Advantages Lack of radiation Lack of iodinated contrast Excellent spatial resolution Detailed parenchymal eval Disadvantages Prolonged imaging time Overcalls degree of stenosis Susceptible to motion artifact Limited in renal insufficiency Newer Technologies 3D Ultrasound Optical Coherence Tomography (OCT) Non-nephrotoxic contrast agents Improved postprocessing dealing with the removal of calcification

4 Applications of Duplex US Peripheral Intervention Applications Access into diseased CFA antegrade and retrograde Access into popliteal vessels Assess patency of SFA stents Assess patency of Renal A. stents Assess significance of carotid atherosclerosis Advantages Available in the lab at time of intervention Low cost Reliable for instent assessment Reliable for stenosis severity assessment in the carotid distribution

5 Duplex Imaging Carotid Disease Severity PSV (cm/sec) < >300 Diameter Stenosis <30% 30-50% 50-70% >70% 75 yo with asymptomatic carotid disease. Tx options: CAS v CEA

6 Duplex Imaging Superficial Femoral Artery (SFA) SFA distally Turbulent flow Shows severity of occlusive disease but does not give enough information to plan the intervention as the inflow is not well seen.

7 Duplex Imaging SFA Instent Restenosis Flow Turbulence and Increased Velocity Intimal Hyperplasia Tx options: PTA vs cryoplasty vs DES vs medical tx with duplex f/u

8 Instent Restenosis Repeat restenosis with debilitating claudication Cutting Balloon then Viabahn Restenosis 6mo Recurrent Restenosis

9 Duplex Imaging Renal Instent Restenosis Flow Turbulence Intimal Hyperplasia AO 80cm/sec RAR 4.2 Single functioning kidney with labile HTN. Tx option: repeat PTA

10 US Guided Access Popliteal Artery and Vein

11 Applications of CTA and MRA Peripheral Intervention Assess arterial disease presence: Carotid Great vessels Renal/mesenteric Aortoiliac Infrainguinal Assess etiology of nonatherosclerotic occlusive disorders FMD Dissection Cystic disease Entrapment Decision for CTA vs MRA is driven by patient (claustrophobia, metal implant, renal insufficiency) institution (access to testing, postprocessing) and physician preferences.

12 Computed Tomography Angiography External Iliac Artery stenosis Excellent spatial resolution and characterization of stenosis severity. 3D Volume rendered reconstruction depicts anatomy identifying access options, crossover potential and inflow disease not seen on duplex. Tx: R CFA retrograde sheath with R EIA PTA/stent Volume Rendered MIP

13 EPD Position and Orientation

14 CTA to Guide Carotid Intervention Favorable Case Successful CAS Confirm lesion severity 80% RICA stenosis Lesion Characteristics Mild calcification Evaluate for tortuosity and proximal occlusive disease Minimal tortuosity and occlusive disease Evaluate for arch type Type A Interesting case due to significant venous phase contrast in the IJ abutting the RICA lesion

15 CAS High Risk Anatomic Features Identified by CTA Sheath Placement Issues Type III arch or Bovine arch (LICA) Arch and CCA calcification CCA and Innominant origin stenosis Excessive tortuosity precluding sheath access ICA issues Circumferential heavy calcification Excessive ICA tortuosity ICA lesion ulceration String sign Roubin et al, Circulation 2006;113 Macdonald et al, Stroke 2009;40

16 CTA - ICA Tortuosity Prohibiting EPD Placement Distally Treatment Options: Proximal protection with CAS vs CEA

17 CTA - CCA Proximal Tortuosity Difficulty placing sheath /delivering stent Treatment Options: CEA vs CCA Guide for CAS

18 CTA - ICA Ulceration Extraluminal Ulceration & Calcification Type C arch, severe Aortoiliac disease, severe ICA ulceration. Tx Option: CEA with local (critical AS)

19 CTA Severe Lesion Calcification Indeterminant for Severity of Stenosis Circumferential calcification favors CEA unable to expand stent Rely on duplex velocity analysis, consider MRA.

20 Unrecognized Calcification Stent Migration During Delivery

21 CTA - Carotid String Sign Not as clear as angiography Angiography confirmed a string sign with limited distal flow Important issue: occluded vessel med tx, string sign CEA

22 Iliac Artery Revascularization Complex Bilateral Stenting TASC D Bilat PTA RCIA BES due to short landing area, LCIA SES due to ectasia

23 Aortoiliac CTA - Inflow Disease Limited evaluation with severe calcification. No definite Inflow disease. Surgical options limited due to severe CAD with ICM EF 10%. Tx: CEA R CFA, SFA, profundoplasty

24 CTA Instent Restenosis CIA Stents Be careful you can be fooled by the postprocessing Volume rendered images looked OK

25 MDCT Allows Sophisticated Processing to Evaluate for Instent Restenosis Distal At Lesion Adjust window levels to evaluate

26 Fibromuscular Dysplasia Evident on CTA Angio CTA Non-inflammatory, nonatherosclerotic disorder Cause is unknown Predominantly affects renal (60-75%) and internal carotid arteries (25-35%), but can affect any artery Small to medium sized vessels Young to middle aged women Causes aneurysm, dissection, and obstruction Hyperplasia of arterial wall Medial fibroplasia (75-80%) String of beads appearance seen on CTA, MRA and Angio.

27 CTA Guide Placement Viabahn Stent for Popliteal Aneurysm 10F sheath, access from LCFA antegrade with preclose vs cutdown

28 CTA Guide Placement Viabahn Stent for Popliteal Aneurysm CT identifies normal to normal SFA and pop a diameter, as well as stent length required

29 Infrainguinal Intervention - CLI CTA: Inflow, Disease Location, Lesion Assessment Crossover favorable L SFA PTA/stent with R EIA PTA/stent

30 Infrainguinal Intervention - CLI CTA: Inflow, Disease Location, Lesion Assessment Recanalization of R TPT occlusion with DES DES 4.0x28mm

31 Magnetic Resonance Angiography External Iliac Artery occlusion Retrograde access from L CFA with crossover. CTO recanalization with R EIA PTA/stent.

32 Fibromuscular Dysplasia Evident on MRA PTA complicated by distal lower pole RA dissection leading to inferior renal infarct

33 Carotid MRA Tendency to Overcall Stenosis 80% by MRA may be 60% by CTA or Angio Transverse cut Coronal MIP and targeted volume rendering of LICA

34 MRA - Subclavian Artery Subclavian A. stenosis or occlusion easily seen Delayed enhancement of ipsi vertebral A Retrograde direction of flow in ipsi vertebral A seen to Identify subclavian steal Femoral or radial approach can be planned Tx: Left SCA PTA / Stent from R CFA approach

35 Subclavian Stenting Technique Arm Claudication

36 Chronic Mesenteric Ischemia MRA Postprandial pain Weight loss Compromised mesenteric flow Celiac artery stenosis SMA stenosis IMA stenosis MIP display of 3D MRA in early arterial phase Tx: SMA stent from L CFA approach

37 MRI/MRA for diagnosis of Cystic Adventitial Disease Incidence 1:1200 therefore not rare Young to middle aged 5:1 men:women Most commonly in popliteal artery (85%) Mucin containing cysts in adventitia Sudden onset of unilateral calf claudication Tx: surgical bypass

38 Popliteal Artery Entrapment Syndrome MRI/MRA Medial displacement of pop A. Occurs in young athletic males Congenital abnormality where popliteal artery is trapped by medial head of gastronemius Exercise-induced claudication Pulses normal at rest Dorsiflexion leads to gastroc contraction with decreased pulse due to squeezing of artery Leads to stenosis, aneurysm or occlusion of the popliteal artery Tx: Surgical release

39 Thromboembolism Upper Extremity MRA Thromboembolism Large emboli Comprised of organized thrombus Originate from Cardiac source Acute occlusion Absent distal pulses Profound ischemia Brachial Artery Embolus Tx: surgical embolectomy

40 Conclusions Duplex remains the standard screening technique for vascular disease Duplex is necessary for stent surveillance CTA is the main imaging tool to plan intervention especially in the carotid arteries CTA has excellent spatial assessment leading to precise sizing CTA is limited by calcification and stents, but progress is being made to overcome these issues MRA is an excellent imaging technique that clearly depicts the anatomy, however has limitations MRA is the superior imaging technique to assess perivascular structures and nonatherosclerotic disease