Structuring the MRA or CTA
Report
E. Kent Yucel, MD
Peripheral angiography
• What is it?
– Complete evaluation of the vascular supply to
at least one leg
– “Runoff”
• Two basic components
– Inflow: infrarenal aorta and both iliacs
– Outflow: one or both legs from groin (CFA) to
the ankle +/- the foot
Peripheral angiography
• Aids to interpretation:
– Symptoms
• Claudication vs. rest pain
• Level of claudication
– Tissue loss
• Requires restoration of pulse in foot
– Pulse exam
• In angio, may be determinative for access site
– Lower extremity noninvasives (LENIs)
LENIs
• Essential in interpretation of the angiogram
• Two components
– Segmental Doppler Pressures (SDPs)
– Impedance Plethysmography (IPGs)
LENIs
• Segmental Doppler Pressures (SDPs)
– Use blood pressure cuffs at thigh and calf (3-4 levels)
– Measure blood pressure using Doppler stethoscope at
the DP or PT in the foot
– Calculate TBI and ABI
– Drop of >20 mmHg between levels or side to side in
thigh
– Normal ABI >1.0, ATI > 1.2
– ABI 0.9-0.3 claudication; 0.5-0.1 rest pain; <0.2 tissue
loss
– Pitfall: incompressible vessels (ABI >1.4)
LENIs
• Impedance Plethysmography (IPG)
– Trace pulsation of leg at same 3-4 levels
– Plus can do a mid-foot level
– Utility
• Cross-check to SDPs
• Incompressible vessels
• Severity of midfoot ischemia (non-pulsatile = limbthreatening ischemia)
Peripheral angiography
• Pre-imaging evaluation
– Symptoms
• Asymptomatic, claudication, rest pain, tissue loss
– Level of disease based on pulses/LENIs
• Inflow (aortoiliac)—bilateral or unilateral
• Femoropopliteal
• Tibiopedal
Basic CT runoff acquisition
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Need “64” detectors or greater
Coverage approx. 120 cm
Collimation 0.6 mm
32 x 0.6 mm = 19.2 mm/rotation
1200/19.2 = 62 rotations or 31 sec
Injection 4-5 cc/sec x 40-50 sec
CT runoff processing
• 1200 mm x 0.7 recon interval = 1714 slices!
• Standard MPRs:
– 3 mm axials
– 5 mm coronal and sagittals
• Workstation:
– Long axis oblique MPRs for quick overview
• Cross reference axials esp. for calcium
– 3D
• Eliminate table and bones
Contrast-Enhanced MRA Runoff
• Time resolved DS-MRA of calves
– 15-20 cc @ 2 cc/sec
– Dedicated coil
– Eliminates venous contamination
• 3-4 station runoff
– Mask + contrast enhanced x 2 phases
– 35-40 cc @ slow fixed or variable rate
– Body coil
Contrast-Enhanced MRA Runoff
• >1500 images in 7-9 series
• Processing—be practical!
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Mask subtraction
Time resolved cine of calf
Full volume rotating MIP of best calf phase
Rotating MIP of all runoff stations
• Refer to source images as needed
Reading an angiogram
• Pelvis
– “Inflow” precedes outflow
– Both sides relevant even with unilateral
symptoms
• Interpret each leg, focusing on leg of
interest
– Do NOT interpret by station
Interpreting an angiogram
• Goal of report should be to point surgeon
toward proper therapy
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TASC II 2007
PTA for shorter, focal lesions
Bypass graft for longer lesions
Restore pulse in foot
Adjunctive interventions: CFA endarterectomy,
profundoplasty, iliac stent
Interpreting an angiogram
• Do NOT mention each stenosis/occlusion
• DO interpret by vascular region
• DO specify whether disease is focal,
multifocal, or diffuse
• DO measure length of disease segment(s)
Aortoiliac
• General issues
– Both sides important
– AAA
– Heavy calcification
• Occlusions
– Infrarenal aorta, CIA +/- EIA
– IIA, CFA involvement
– AAA
• Stenosis
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Short < 3 cm
Medium 3-10 cm
Diffuse >10 cm
Intraluminal
Infrainguinal
• Evaluate each side separately
• Stenosis/occlusion
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Single vs. multiple
Short: each <5 cm
Medium: 5-15 cm
Long: >15 cm or Total, “diffuse”
Heavily calcified, intraluminal
• Location
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Superficial femoral, suprageniculate popliteal
Infrageniculate popliteal
Tibial
Comment on common and deep femoral arteries
• Runoff: continuous to foot or isolated segment
Reading an angiogram
• DO characterize tibial runoff
• DO specify level of reconstitution of
continuously patent vessels (or isolated
vessels if none continuous)
• Do mention supply/status of PT and DP in
foot
Reading an angiogram
• Common considerations
– “Focal” means “good for PTA”
– “Diffuse” for stenosis or “long-segment” for
occlusion means “bypass graft”
– Even moderate iliac stenosis may merit PTA to
support infrainguinal bypass graft
– Comment on above-knee and below-knee
popliteal
– Mention vessels “in continuity” to foot