Download as PDF, PPTX
![‘Surgical (endovascular) Segments’
• aorto-iliac =‘suprainguinal’ =‘inflow’
• common fem. a. important landmark;
bypass target/source
[deep fem.a.] [important collateral if SFA
occluded; post amput.]
• femoropoplital a. ‘infra-inguinal’ = ‘runoff’
reconstitution of pop. a.
(pop.: P1, P2, P3) above (P1) or below (P3) knee
• below knee aa. only relevant in CLI,
can ignore in claudicants
• pedal arteries only CLI, bypass targets](https://image.slidesharecdn.com/tipsandtricksinvascularimaginglowerextremitycta-161026144905/75/Tips-and-Tricks-in-Vascular-Imaging-Lower-Extremity-CTA-21-2048.jpg)
![Systematic Approach to Reading Lower
Extremity CTA
answer clinical questions rather than listing lesions
• intermittent claudication?
critical limb ischemia ?
-- determines how you read scan
• organize first by leg, and then by station
Right/left lower extremity
- aortoiliac (inflow disease [above inguinal lig.])
- (common fem a.); - (deep femoral artery)
- femoropopliteal artery; SFA, P1, P2, P3
- below knee (infrapop.) runoff: 2 vessels cross ankle)
- (pedal)](https://image.slidesharecdn.com/tipsandtricksinvascularimaginglowerextremitycta-161026144905/75/Tips-and-Tricks-in-Vascular-Imaging-Lower-Extremity-CTA-22-2048.jpg)
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Tips and Tricks in Vascular Imaging (Lower Extremity CTA)
- 1. Tips and Tricksin Vascular Imaging Lower Extremity CTA North American Society of Cardiovascular Imaging Annual Meeting, Baltimore MD, October 15-18, 2016 Dominik Fleischmann, Richard Hallett Division of Cardiovascular Imaging Department of Radiology, Stanford University
- 2. Tips and Tricksin Vascular Imaging LOWER EXTREMITY CTA • Clinical context • Scanning and Contrast Technique • Postprocessing • Interpretation & Reporting
- 3. Tip 1: ClinicalContext Role of Imaging in PAD* *Peripheral Artery Disease
- 4. DSA Peripheral Artery Disease(PAD) • manifestation of atherosclerosis in arteries supplying blood to lower extremities Clinical Symptoms: • at 'stress‘: intermittent claudiaction perfusion pressure (ABI<0.8) can‘t keep up with increased demand when walking; ischemic tissue is muscle • at 'rest': critical limb ischemia perfusion pressure<baseline demand; ischemic tissue is skin, nerve- connective tissue
- 5. DSA Diagnosis and Stagingof PAD • symptoms + • ankle-brachial-index • poor correlation of symptoms and ABI with number, location and severity of lesions à i.e. calf claudiaction can be caused by isolated vs a combination of iliac or femoropolpliteal lesions Role of Imaging NOT diagnosis / staging • mapping of lesions to symptoms for treatment planning
- 6. 16x.75mm 2.0mm/1.0mm post PTA post PTA / stent 73 yearold woman with intermittent claudication bilaterally MIP multipath CPR
- 7. TASC II Criteria TransatlanticSociety Consensus (2007)
- 8. Type A endovascular TASC IICriteria Transatlantic Society Consensus (2007) Type B Type C Type D surgical aortoiliac femoropopliteal
- 9. Tip 2: Technique Scanningand CM Injection
- 10. Scanning and CMInjection • no fancy scanner needed: any CT scanner with ~1mm thickness (≥16-slice MDCT); • ideally isotropic resolution (sub-millimeter) Account for slow bolus transit in diseased arteries: • long injection (~35s) • scan slow (40s) • add delayed acquisition, if needed
- 11. Peripheral Arterial Enhancement (20patients with PAOD) Aorta 0 30 60 90 120 150 180 0 10 20 30 40 50 tCMT Popliteal artery 0 30 60 90 120 150 180 0 10 20 30 40 50 tAPT Aorto-popliteal .. Transit time Transit speed mean: 10 s 65 mm/s min: 4 s 177 mm/s max: 24 s 30 mm/s tAPT Radiology 236 (Sept.) 2005 tAPT= aorto-popliteal transit time tCMT= contrast medium transit time
- 12. Integrated Scanning-Injection Protocol Scantime:40s for ALL patients (pitch variable) (automated tube current modulation) Inj.duration: 35s for ALL patients Delay: bolus triggering 64 - channel Lower Extremities weight Biphasic Injection <55kg 20 mL (4.0mL/s) + 96 mL (3.2mL/s) <65kg 23 mL (4.5mL/s) + 108 mL (3.6mL/s) 75kg 25 mL (5.0mL/s) + 120 mL (4.0mL/s) >85kg 28 mL (5.5mL/s) + 132 mL (4.4mL/s) >95kg 30 mL (6.0mL/s) + 144 mL (4.8mL/s) 64
- 13. 82 y.o. woman bilateralclaudication re>lt Scanner: 64 × 0.6mm Scantime: 40 s Injection (biphasic): 35 s 20mL (4 mL/s) + 95mL (3.2 mL/s) Delay: 'CareBolus'
- 14. Peripheral CTA Scanning Range ScanningRange 1 celiac artery (Th12) à toes (105 – 130 cm) Optional Additional Scanning Range 2 above the knees à toes Always pre-programmed, but only initiated by technologist if no contrast in crural vessels
- 15.
- 16.
- 17. Tips and Tricksfor Lower Extremity CTA Postprocessing • greatest challenge in lower extremity CTA: difference between quick read vs. painful (literally) scrolling through images • axial (transverse) images inadequate, except in acute ischemia (i.e. thromboembolic) • need longitudinal cross sections (MPR/CPR) • ideally, mapping of lesions needs a ‘map’: ‘multipath curved planar reformations’ • try to delegate (3D-Lab, trained technologist) if routinely performing runoff CTAs
- 18. • 59 year oldman with intermittent claudication bilaterally. • Past medical history significant for prior Stent-PTA of right EIA MultiPath-CPR;thin,stretched DSA ThinCPRRight,stretched post kissing stent pre- PTA/re-stent of stent-stenosis MultiPath-CPR;thin,stretched,close-up MIP CPRs DSA
- 19. Display on PACS MIPMulti-Path CPR single CPR
- 20. Tip 4: Interpretation &Reporting
- 21. ‘Surgical (endovascular) Segments’ • aorto-iliac=‘suprainguinal’ =‘inflow’ • common fem. a. important landmark; bypass target/source [deep fem.a.] [important collateral if SFA occluded; post amput.] • femoropoplital a. ‘infra-inguinal’ = ‘runoff’ reconstitution of pop. a. (pop.: P1, P2, P3) above (P1) or below (P3) knee • below knee aa. only relevant in CLI, can ignore in claudicants • pedal arteries only CLI, bypass targets
- 22. Systematic Approach toReading Lower Extremity CTA answer clinical questions rather than listing lesions • intermittent claudication? critical limb ischemia ? -- determines how you read scan • organize first by leg, and then by station Right/left lower extremity - aortoiliac (inflow disease [above inguinal lig.]) - (common fem a.); - (deep femoral artery) - femoropopliteal artery; SFA, P1, P2, P3 - below knee (infrapop.) runoff: 2 vessels cross ankle) - (pedal)
- 23. Tips and Tricksin Vascular Imaging LOWER EXTREMITY CTA: SUMMARY • Clinical context ■ goal is to map lesions to clinical symptoms ■ ‘stress’ (claudication) vs. ‘resting’ (CLI) ischemia • Scanning and Contrast Technique ■ inject long, and scan slow • Postprocessing ■ curved planar reformats • Interpretation & Reporting ■ don’t read study without knowing symptoms ■ answer clinical question rather listing lesions
- 24. SAM Question Which ofthe following statements regarding lower extremity CTA is correct ? A. the diagnosis of peripheral artery disease is fundamentally based on imaging B. symptoms and ankle-pressure-index (ABI) not only establish the diagnosis of peripheral artery disease, but also accurately localize the anatomic level of obstruction C. the role of imaging in peripheral artery disease is not making the diagnosis, but to map (localize) obstructive lesions for treatment planning D. in patients with calf claudication, evaluation of the distal below- knee arteries is important for treatment planning
- 25. SAM Question ANSWER Whichof the following statements regarding lower extremity CTA is correct ? A. the diagnosis of peripheral artery disease is fundamentally based on imaging B. symptoms and ankle-pressure-index (ABI) not only establish the diagnosis of peripheral artery disease, but also accurately localize the anatomic level of obstruction C. the role of imaging in peripheral artery disease is not making the diagnosis, but to map (localize) obstructive lesions for treatment planning D. in patients with calf claudication, evaluation of the distal below- knee arteries is important for treatment planning Reference: Fleischmann D, Hallett RL, Rubin GD. CT angiography of peripheral arterial disease. J Vasc Interv Radiol. 2006;17:3-26
- 26. Thank you… Dept. ofRadiology, Stanford University, CA North American Society of Cardiovascular Imaging Annual Meeting, Baltimore MD, October 15-18, 2016