Lawrence N' Tanenbaum, M'D' FACR

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CT Angiographychallenges and pitfalls

• Lawrence N. Tanenbaum, M.D. FACR
• Seton Hall School of Graduate Medical Education
• Edison Imaging JFK Medical Center
• www.drtmasters.com drt_at_drtmasters.com
• Edison, New Jersey

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CT angiographypitfalls

• timing
• pulsation artifacts
• Ca
• stent
• data load
• single vs multiphase assessment
• iodinated contrast agent
• reimbursement

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CT angiographytiming issues

• variability in arrival and distribution with
  cardiac output
• tailored scan initiation
• enhancement triggered (SmartPrep, Care bolus)
• timing run
• best guess
• surveillance location varies with scanner speed

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CT Angiography
enhancement triggered scanning
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CT angiographytiming issues

• better late than. early
• large(r) window of opportunity (than with MRA)
• streak artifact
• saline flush

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CT angiographypitfalls

• timing
• motion effects
• Ca
• stent
• single vs multiphase assessment
• iodinated contrast / radiation
• data load
• reimbursement

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motion effects

• pseudo-dissection
• segmented data
• cardiac gating
• blurring / Ca

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aortic dissection
Charite
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12 sec
64 ch
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motion effects

• pseudo-dissection
• blurring / Ca blooming
• temporal resolution
• shutter speed
• .33 - .35 sec
• .40 - .50 sec

0.5 sec
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segmented data
Original Image
.35
.40
.50
250 ms
50 ms
100 ms
motion
resolution
CNR / SNR
Courtesy of E. Nagel, M.D. German Heart
Institute, Berlin
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64 channels .5 sec
64 channels .35 sec
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.35 sec
.5 sec
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.35 sec
.5 sec
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.625 mm
.5 sec
.4 sec
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64 ch .4 sec
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64 ch .4 sec
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CT angiographypitfalls

• timing
• pulsation artifacts
• Ca
• stent
• single vs multiphase assessment
• iodinated contrast / radiation
• data load
• reimbursement

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siphon ASVD LS 16 .625 mm
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siphon ASVD LS 16 .625 mm
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CTA .625 / .55
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CTA
MRA
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conv angio
CTA
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ICA occlusion
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CT angiographypitfalls

• timing
• pulsation artifacts
• Ca
• metal stents / clips
• single vs multiphase assessment
• iodinated contrast / radiation
• data load
• reimbursement

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64
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16 channel CT
8 channel 3T
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intimal hyperplasia
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Type II endoleak 64 ch
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Type I endoleak 16 ch
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64 ch
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64 ch
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64 ch
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64 ch
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CT angiographypitfalls

• timing
• pulsation artifacts
• Ca
• stents
• single vs multiphase assessment
• iodinated contrast / radiation
• data load
• reimbursement

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370 / 100 cc
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3D ECTRICKS
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32 element 16 channel calf-foot-ankle PA coil
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runoff
3D TRICKS
2D TOF
J Kevin DeMarco
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is right PTA patent?
delayed arrival left leg
collateral filling!
way too early
PTA
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is left dorsalis pedis patent?
veins on left
retrograde flow!
veins on right!
dorsalis pedis
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3D elliptical centric TRICKS 10 -15 cc Gd
retrograde flow
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CT angiographypitfalls

• timing
• pulsation artifacts
• Ca
• stents
• single vs multiphase assessment
• iodinated contrast /radiation
• reduced volume, focused exam
• data load
• reimbursement

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CT Angiography370 concentration

• Brain or neck 40-50 cc 15-18 grams
• Full neuro 50-75 cc 18-28 grams
• Aorto-iliac 50-75 cc 18-28 grams
• Runoff to feet 75-100 cc -28-37 grams
• Pulmonary 75-100 cc -28-37 grams
• Coronary 80-100 cc -30-37 grams

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16 channel CTpatient benefits

• increase in channels reduces patient dose
• increased imaging / scatter ratio
• shared helical data more dose efficient
• reduced mAs

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140 kV 91 mAs
140 kV 68 mAs
140 kV 55 mAs
140 kV 230 mAs
SmartMA
140 kV 230 mAs
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VCT 64 .625 mm
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259 mA .40 sec 5 251 mA .40 sec 15 251 mA .40
sec 25 251 mA .40 sec 35 281 mA .40 sec 45 475
mA .40 sec 55 612 mA .40 sec 65 613 mA .40 sec
75 613 mA .40 sec 85 446 mA .40 sec 95
EKG dose modulation
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CT angiographypitfalls

• timing
• pulsation artifacts
• Ca
• stents
• single vs multiphase assessment
• iodinated contrast / radiation
• data load
• reimbursement

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CT angiographydata volume

• 1500-3000 slices used for VR
• processing time
• networking issues
• workstation processing power
• archiving cost
• 3.75 mm images to PACS / CD / film
• review

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CT angiographypitfalls

• timing
• pulsation artifacts
• Ca
• stents
• single vs multiphase assessment
• iodinated contrast / radiation
• data load
• reimbursement

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CTA CPT codes

• Head 70496
• Neck 70498
• Chest 71275
• Pelvis 72191
• Abdomen 74175
• Extremity upper 73206, lower 73706
• Abd Ao bilat iliofemoral LE runoff 75635

Las Vegas 2000
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CT Angiographychallenges and pitfalls