- Email: [email protected]
Computed Tomography Angiography and the Incidence of Unruptured Aneurysms
Perspectives Commentary on: Prevalence of Asymptomatic Incidental Aneurysms: A Review of 2685 Computed Tomographic Angiograms by Agarwal et al. World Neurosurg 2014 http://dx.doi.org/10.1016/j.wneu.2013.01.082
Felipe C. Albuquerque, M.D. Assistant Director of Endovascular Neurosurgery Division of Neurological Surgery Barrow Neurological Institute St. Joseph’s Hospital and Medical Center
Computed Tomography Angiography and the Incidence of Unruptured Aneurysms Felipe C. Albuquerque
n this issue of WORLD NEUROSURGERY, Agarwal et al. report their experience in the evaluation of 2195 computed tomography (CT) angiograms. Their review revealed that 39 images of patients demonstrated unruptured asymptomatic intracranial aneurysms producing a prevalence of 1.8%. Previous analyses reported angiographic and autopsy detection rates of 0.8%e6% (1-4).
I
associated with a lower complication rate than diagnostic angiography. CT angiography can be performed quickly and is a useful tool for future follow-up of patients harboring unruptured intracranial aneurysms. At our institution, CT angiography has supplanted diagnostic angiography as the initial assessment modality for patients suspected of harboring an intracranial aneurysm.
Although Agarwal et al. made an effort to exclude patients who had CT angiograms for reasons that were possibly associated with an aneurysm, bias still exists in this evaluation. Prior studies have reported that CT angiography is 94% sensitive in the detection of intracranial aneurysms (5). Similarly, aneurysms less than 3 mm may not be detectable with CT angiography. Finally, this cohort does not truly represent an asymptomatic population as these patients underwent CT angiography for some reason. All of these factors probably lead to an underestimation of the prevalence of unruptured intracranial aneurysms in the general population.
A critical issue central to the discovery of unruptured aneurysms is their future management. Debate persists as to whether small aneurysms should be treated. Agarwal et al. do not discuss their management of the 39 cases harboring unruptured intracranial aneurysms. If their estimate of 1.8% is actually lower than the true incidence and if one considers the sensitivity of CT angiography, then unruptured aneurysms occur in approximately 1 in 50 individuals. Certainly, a small percentage of these aneurysms go on to produce subarachnoid hemorrhage. This complicates the issue of treatment in this patient population. Although establishing a size cutoff for treatment has been elusive and a subject of great debate, CT angiography provides a noninvasive means of investigating this issue further.
Despite these drawbacks, CT angiography is a useful tool in the assessment of this patient population. Certainly it is
REFERENCES 1. Chason JL, Hindman WM: Berry aneurysms of the circle of Willis; results of a planned autopsy study. Neurology 8:41-44, 1958. 2. Cohen MM: Cerebrovascular accidents; a study of two hundred one cases. AMA Arch Pathol 60:296-307, 1955. 3. Crompton MR: Mechanism of growth and rupture in cerebral berry aneurysms. Br Med J 1:1138-1142, 1966.
Key words Aneurysms - Asymptomatic incidental aneurysms - Computed tomography angiography - CTA -
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4. De la Monte SM, Moore GW, Monk MA, Hutchins GM: Risk factors for the development and rupture of intracranial berry aneurysms. Am J Med 78:957-964, 1985. 5. Luo Z, Wang D, Sun X, Zhang T, Liu F, Dong D, Chan NK, Shen B: Comparison of the accuracy of subtraction CT angiography performed on 320detector row volume CT with conventional CT angiography for diagnosis of intracranial aneurysms. Eur J Radiol 81:118-122, 2012.
Intracranial aneurysms Prevalence Unruptured aneurysms
Citation: World Neurosurg. (2014). http://dx.doi.org/10.1016/j.wneu.2013.02.081 Journal homepage: www.WORLDNEUROSURGERY.org Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2014 Elsevier Inc. All rights reserved.
Division of Neurological Surgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA To whom correspondence should be addressed: Felipe C. Albuquerque, M.D. [E-mail: [email protected]]
Abbreviations and Acronyms CT: Computed tomography
WORLD NEUROSURGERY 00 [0]: 1, MONTH 2014
www.WORLDNEUROSURGERY.org
1
Felipe C. Albuquerque, M.D. Assistant Director of Endovascular Neurosurgery Division of Neurological Surgery Barrow Neurological Institute St. Joseph’s Hospital and Medical Center
Computed Tomography Angiography and the Incidence of Unruptured Aneurysms Felipe C. Albuquerque
n this issue of WORLD NEUROSURGERY, Agarwal et al. report their experience in the evaluation of 2195 computed tomography (CT) angiograms. Their review revealed that 39 images of patients demonstrated unruptured asymptomatic intracranial aneurysms producing a prevalence of 1.8%. Previous analyses reported angiographic and autopsy detection rates of 0.8%e6% (1-4).
I
associated with a lower complication rate than diagnostic angiography. CT angiography can be performed quickly and is a useful tool for future follow-up of patients harboring unruptured intracranial aneurysms. At our institution, CT angiography has supplanted diagnostic angiography as the initial assessment modality for patients suspected of harboring an intracranial aneurysm.
Although Agarwal et al. made an effort to exclude patients who had CT angiograms for reasons that were possibly associated with an aneurysm, bias still exists in this evaluation. Prior studies have reported that CT angiography is 94% sensitive in the detection of intracranial aneurysms (5). Similarly, aneurysms less than 3 mm may not be detectable with CT angiography. Finally, this cohort does not truly represent an asymptomatic population as these patients underwent CT angiography for some reason. All of these factors probably lead to an underestimation of the prevalence of unruptured intracranial aneurysms in the general population.
A critical issue central to the discovery of unruptured aneurysms is their future management. Debate persists as to whether small aneurysms should be treated. Agarwal et al. do not discuss their management of the 39 cases harboring unruptured intracranial aneurysms. If their estimate of 1.8% is actually lower than the true incidence and if one considers the sensitivity of CT angiography, then unruptured aneurysms occur in approximately 1 in 50 individuals. Certainly, a small percentage of these aneurysms go on to produce subarachnoid hemorrhage. This complicates the issue of treatment in this patient population. Although establishing a size cutoff for treatment has been elusive and a subject of great debate, CT angiography provides a noninvasive means of investigating this issue further.
Despite these drawbacks, CT angiography is a useful tool in the assessment of this patient population. Certainly it is
REFERENCES 1. Chason JL, Hindman WM: Berry aneurysms of the circle of Willis; results of a planned autopsy study. Neurology 8:41-44, 1958. 2. Cohen MM: Cerebrovascular accidents; a study of two hundred one cases. AMA Arch Pathol 60:296-307, 1955. 3. Crompton MR: Mechanism of growth and rupture in cerebral berry aneurysms. Br Med J 1:1138-1142, 1966.
Key words Aneurysms - Asymptomatic incidental aneurysms - Computed tomography angiography - CTA -
-
4. De la Monte SM, Moore GW, Monk MA, Hutchins GM: Risk factors for the development and rupture of intracranial berry aneurysms. Am J Med 78:957-964, 1985. 5. Luo Z, Wang D, Sun X, Zhang T, Liu F, Dong D, Chan NK, Shen B: Comparison of the accuracy of subtraction CT angiography performed on 320detector row volume CT with conventional CT angiography for diagnosis of intracranial aneurysms. Eur J Radiol 81:118-122, 2012.
Intracranial aneurysms Prevalence Unruptured aneurysms
Citation: World Neurosurg. (2014). http://dx.doi.org/10.1016/j.wneu.2013.02.081 Journal homepage: www.WORLDNEUROSURGERY.org Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2014 Elsevier Inc. All rights reserved.
Division of Neurological Surgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA To whom correspondence should be addressed: Felipe C. Albuquerque, M.D. [E-mail: [email protected]]
Abbreviations and Acronyms CT: Computed tomography
WORLD NEUROSURGERY 00 [0]: 1, MONTH 2014
www.WORLDNEUROSURGERY.org
1