Korean J Radiol.  2011 Oct;12(5):547-553. 10.3348/kjr.2011.12.5.547.

Prevalence of Unruptured Intracranial Aneurysm on MR Angiography

• Jeon TY
• Jeon P
• Kim KH

• KMID: 1116439
• DOI: http://doi.org/10.3348/kjr.2011.12.5.547

Abstract

OBJECTIVE
To evaluate the prevalence of incidentally found unruptured intracranial aneurysms (UIAs) on the brain MR angiography (MRA) from a community-based general hospital.
MATERIALS AND METHODS
This was a prospectively collected retrospective study, carried out from January 2004 to December 2004. The subjects included 3049 persons from a community-based hospital in whom MRA was performed according to a standardized protocol in an outpatient setting. Age- and sex-specific prevalence of UIAs was calculated. The results by MRA were compared with intra-arterial digital subtraction angiography (DSA) findings.
RESULTS
Unruptured intracranial aneurysms were found in 137 (5%) of the 3049 patients (M:F = 43:94; mean age, 60.2 years). The prevalence of UIAs was 5% (n = 94) in women and 4% (n = 43) in men, respectively (p = 0.2046) and showed no age-related increase. The most common site of aneurysm was at the distal internal carotid artery (n = 64, 39%), followed by the middle cerebral artery (n = 40, 24%). In total, 99% of aneurysms measured less than 12 mm, and 93% of aneurysms measured less than 7 mm. Direct comparisons between MRA and DSA were available in 70 patients with 83 UIAs; the results revealed two false positive and two false negative results.
CONCLUSION
This community-hospital based study suggested a higher prevalence of UIAs observed by MRA than previously reported. These findings should be anticipated in the design and use of neuroimaging in clinical practice.

Keyword

MR angiography; Intracranial aneurysm; Prevalence

MeSH Terms

Adolescent
Adult
Aged
Aged, 80 and over
Aneurysm, Ruptured/diagnosis
Angiography, Digital Subtraction
Cerebral Angiography
Female
Humans
Incidental Findings
Intracranial Aneurysm/*diagnosis/radiography
*Magnetic Resonance Angiography
Male
Middle Aged
Young Adult

Figure

• 

  Fig. 1 False-negative intracranial aneurysm on MR angiography in 58-year-old woman.A, B. Maximum intensity projection image demonstrates two aneurysms (arrows) on right middle cerebral artery bifurcation (A) and M1 segment of left middle cerebral artery (B), respectively. C, D. Digital subtraction angiography image demonstrates another 2-mm-sized aneurysm (arrowhead) on M1 segment of left middle cerebral artery, in addition to two aneurysms seen on maximum intensity projection of MR angiography.

• 

  Fig. 2 False-positive intracranial aneurysm on MR angiography in 64-year-old woman.A. Maximum intensity projection image demonstrates 2-mm-sized aneurysm (arrow) on A2 segment of left anterior cerebral artery. B. Volume rendering image shows presence of aneurysm (arrow) at same location. C. Digital subtraction angiography image demonstrates no aneurysm. Perforator (arrowhead) of anterior cerebral artery with downward direction mimics aneurysm.

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