Can CTA or MRA replace Can CTA or MRA replace intra-arterial digital intra-arterial digital subtraction subtraction angiography (DSA) in angiography (DSA) in the investigation of the investigation of isolated third nerve isolated third nerve palsy? palsy? William A. Fletcher, William A. Fletcher, M.D., FRCPC M.D., FRCPC University of Calgary University of Calgary
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Can CTA or MRA replace intra-arterial digital subtraction angiography (DSA) in the investigation of isolated third nerve palsy? William A. Fletcher, M.D.,
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Can CTA or MRA replace Can CTA or MRA replace intra-arterial digital intra-arterial digital
subtraction angiography subtraction angiography (DSA) in the investigation (DSA) in the investigation
of isolated third nerve of isolated third nerve palsy?palsy?
William A. Fletcher, M.D., William A. Fletcher, M.D., FRCPCFRCPC
University of CalgaryUniversity of Calgary
DSA?DSA?Or is MRA or CTA Or is MRA or CTA sufficient? sufficient?
Kissel et al (1983)Kissel et al (1983)25 aneurysmal palsies: 25 aneurysmal palsies: 12% pupil-sparing incomplete12% pupil-sparing incomplete
Third Nerve Palsy – Can CTA Third Nerve Palsy – Can CTA or MRA Replace DSA?or MRA Replace DSA?
• 3 Questions:3 Questions:– Sensitivity of CTA and MRA in Sensitivity of CTA and MRA in
detecting aneurysms? detecting aneurysms?
– Prevalence of aneurysm in III palsy?Prevalence of aneurysm in III palsy?• With pupil-sparing incomplete palsyWith pupil-sparing incomplete palsy
• With relative pupil-sparing palsyWith relative pupil-sparing palsy
– Risk of complications from DSA?Risk of complications from DSA?
III Nerve Palsy – MRA?III Nerve Palsy – MRA?
• Jacobson and Trobe (1999):Jacobson and Trobe (1999):– Risk of MRA missing P Comm Risk of MRA missing P Comm
aneurysm:aneurysm:
1.5%1.5%
Posterior Communicating Posterior Communicating Artery (P-Comm) Aneurysms Artery (P-Comm) Aneurysms Causing Third Nerve Palsy Causing Third Nerve Palsy
• Jacobson and Trobe (1999):Jacobson and Trobe (1999):
AneurysmAneurysm
DiameterDiameter
Proportion Proportion causing causing palsy palsy
(%)(%)
Not Not detected detected by MRA by MRA
(%)(%)
Proportion Proportion causing palsy causing palsy
& not & not detected by detected by
MRA (%)MRA (%)
5 mm5 mm 91.391.3 x 3 x 3 = 2.7= 2.7
5 mm5 mm 8.7 8.7 x 46x 46 = 4.0= 4.0
P-Comm Aneurysms Causing P-Comm Aneurysms Causing Third Nerve Palsy Third Nerve Palsy
• Jacobson and Trobe (1999):Jacobson and Trobe (1999):
AneurysAneurysmDiametmDiamet
erer
Proportion Proportion causing palsy causing palsy
& not & not detected by detected by
MRA (%)MRA (%)
8-Year 8-Year RupturRupture Rate e Rate
(%) (%)
Proportion not Proportion not detected by detected by
MRA and liable MRA and liable to rupture (%)to rupture (%)
5 mm5 mm 2.72.7 x 31 x 31
= 0.85= 0.85
5 mm5 mm 4.0 4.0 x 16x 16 = 0.65= 0.65
Total 1.5Total 1.5
P-Comm AneurysmsP-Comm Aneurysms
• International Study of Unruptured International Study of Unruptured Intracranial Aneurysms (ISUIA) Intracranial Aneurysms (ISUIA) (2003)(2003)
• Yanaka et al (2003):Yanaka et al (2003):– 16 patients with acute third nerve 16 patients with acute third nerve
palsiespalsies– all aneurysms all aneurysms 10 mm 10 mm– 1 aneurysm (6mm) ruptured on day 31 aneurysm (6mm) ruptured on day 3
risk of rupture unknownrisk of rupture unknown
P-Comm Aneurysms Causing P-Comm Aneurysms Causing III Nerve Palsy III Nerve Palsy
• Jacobson and Trobe (modified):Jacobson and Trobe (modified):
AneurysmAneurysm
DiameterDiameter
Proportion Proportion causing causing palsy palsy
(%)(%)
Not Not detected detected by MRA by MRA
(%)(%)
Proportion not Proportion not detected by detected by
MRA and liable MRA and liable to rupture (%)to rupture (%)
5 mm5 mm 91.391.3 x 3 x 3 = 2.7= 2.7
5 mm5 mm 8.7 8.7 x 46x 46 = 4.0= 4.0
Total 6.7Total 6.7
MRA Sensitivity for Detecting MRA Sensitivity for Detecting AneurysmsAneurysms
• White et al (2000):White et al (2000):– 3 mm: 94%3 mm: 94%
• Kupersmith et al (2005):Kupersmith et al (2005):– Prospective study of MRAProspective study of MRA
MRA Sensitivity for Detecting MRA Sensitivity for Detecting AneurysmsAneurysms
• Kupersmith et al (2005):Kupersmith et al (2005):
MRA Sensitivity for Detecting MRA Sensitivity for Detecting AneurysmsAneurysms
• White et al (2000):White et al (2000):– 3 mm: 94%3 mm: 94%
• Kupersmith et al (2005):Kupersmith et al (2005):– Prospective study of MRAProspective study of MRA– 3 mm: 100% (n = 42)3 mm: 100% (n = 42)– Confidence interval: 93% - 100%Confidence interval: 93% - 100%
CTA Sensitivity for Detecting CTA Sensitivity for Detecting AneurysmsAneurysms
CTA Sensitivity for Detecting CTA Sensitivity for Detecting AneurysmsAneurysms
• Hoh et al (2004):Hoh et al (2004):– 225 aneurysms225 aneurysms
• 109 ruptured109 ruptured• 114 unruptured114 unruptured• 28 P Comm aneurysms28 P Comm aneurysms• Sensitivity: 100%Sensitivity: 100%
• GenderGender– M:F ratio - 1:3 for PComm aneurysmsM:F ratio - 1:3 for PComm aneurysms
– Capo et al (1992) & Renowden et al (1993):Capo et al (1992) & Renowden et al (1993):• 75 patients with III palsy:75 patients with III palsy: womenwomen menmen