301
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Abstract
OBJECT In this article, pathological, radiological, and clinical information regarding unruptured intracranial aneurysms is reviewed. METHODS Treatment decisions require that surgeons and interventionists take into account information obtained in pathological, radiological, and clinical studies of unruptured aneurysms. The author has performed a detailed review of the literature and has compared, contrasted, and summarized his findings. Unruptured aneurysms may be classified as truly incidental, part of a multiple aneurysm constellation, or symptomatic by virtue of their mass, irritative, or embolic effects. Unruptured aneurysms with clinical pathological profiles resembling those of ruptured lesions should be considered for treatment at a smaller size than unruptured lesions with profiles typical of intact aneurysms, as has been determined at autopsy in patients who have died of other causes. The track record of the surgeon or interventionist and the institution in which treatment is to be performed should be considered while debating treatment options. In cases in which treatment is not performed immediately, ongoing periodic radiological assessment may be wise. Radiological investigations to detect unruptured aneurysms in asymptomatic patients should be restricted to high-prevalence groups such as adults with a strong family history of aneurysms or patients with autosomal dominant polycystic kidney disease. All patients with intact lesions should be strongly advised to discontinue cigarette smoking if they are addicted. CONCLUSIONS The current state of knowledge about unruptured aneurysms does not support the use of the largest diameter of the lesion as the sole criterion on which to base treatment decisions, although it is of undoubted importance.
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Affiliation(s)
- Bryce Weir
- Section of Neurosurgery, The University of Chicago, Illinois 60637-1470, USA
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302
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Winn HR, Jane JA, Taylor J, Kaiser D, Britz GW. Prevalence of asymptomatic incidental aneurysms: review of 4568 arteriograms. J Neurosurg 2002; 96:43-9. [PMID: 11794602 DOI: 10.3171/jns.2002.96.1.0043] [Citation(s) in RCA: 162] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT The prevalence of unruptured cerebral aneurysms is unknown, but is estimated to be as high as 5%. The goal of this study was to determine the prevalence of asymptomatic incidental aneurysms. METHODS The authors studied all cerebral arteriography reports produced at a single institution, the University of Virginia, between April 1969 and January 1980. A review of 3684 arteriograms demonstrated 24 cases of asymptomatic aneurysms, yielding a prevalence rate of 0.65%. The majority (67%) of the 24 patients harboring unruptured aneurysms were women. More than 90% of the unruptured aneurysms were located in the anterior circulation and in locations similar to those found in patients with ruptured aneurysms. Nearly 80% of the aneurysms were smaller than 1 cm in their greatest diameter. The frequency of asymmetrical unruptured aneurysms (0.6-1.5%) was constant throughout all relevant age ranges (35-84 years). CONCLUSIONS While keeping in mind appropriate caveats in extrapolating from these data, the prevalence rate of asymptomatic unruptured aneurysms found in the present study allows an estimation of the yearly rate of rupture of these lesions. The authors suggest that this yearly rate of rupture falls within the range of 1 to 2%.
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Affiliation(s)
- H Richard Winn
- Department of Neurosurgery, University of Washington, Harborview Medical Center, Seattle 98104, USA.
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303
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Abstract
The aim is to review the background underlying the debate related to the alternative nomenclatures for and the most appropriate diagnostic evaluation of patients with thunderclap headache. The clinical profile and differential diagnosis of thunderclap headache is described, and a nosological framework and diagnostic approach to this group of patients is proposed.
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Affiliation(s)
- D W Dodick
- Department of Neurology, Mayo Clinic, 13400 East Shea Boulevard, Scottsdale, Arizona 85259, USA.
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304
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White PM, Teadsale E, Wardlaw JM, Easton V. What is the most sensitive non-invasive imaging strategy for the diagnosis of intracranial aneurysms? J Neurol Neurosurg Psychiatry 2001; 71:322-8. [PMID: 11511704 PMCID: PMC1737547 DOI: 10.1136/jnnp.71.3.322] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVES To determine whether combining non-invasive tests for intracranial aneurysms together would significantly improve aneurysm detection over individual tests. METHODS 114 patients undergoing intra-arterial digital subtraction angiography to confirm or exclude an intracranial aneurysm were also examined by CT angiography, MR angiography, and transcranial power Doppler ultrasound. The reviewers and ultrasonographers were blinded to the angiogram result, other imaging results and all clinical information. RESULTS The combination of non-invasive tests did improve diagnostic performance on a per patient basis. The combination of power Doppler and CT angiography had the greatest sensitivity for aneurysm detection (0.83; 05% confidence interval (95% CI) 0.66-0.93) and the level of agreement for this strategy with the reference angiographic standard was excellent (kappa 0.84; 95% CI 0.72-0.95). The improvement in sensitivity of adding power Doppler to CT angiography was not significant (p=0.55) but the improvement in the level of agreement with the reference standard was substantial. However, even the most sensitive combination strategy performed poorly in the detection of small (3-5 mm) and very small (<3 mm) aneurysms with a sensitivity of 0.43 (95% CI 0.23-0.66) and 0.00 (95% CI 0.00-0.31) respectively. CONCLUSIONS The addition of transcranial power Doppler ultrasound to either CT angiography or MR angiography does improve diagnostic performance on a per patient basis but aneurysms of 5 mm or smaller can still not be reliably identified by current standard clinical non-invasive imaging modalities.
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MESH Headings
- Adult
- Aged
- Cerebral Angiography/adverse effects
- Cerebral Angiography/instrumentation
- Cerebral Angiography/methods
- Cerebral Angiography/standards
- False Negative Reactions
- Female
- Humans
- Intracranial Aneurysm/diagnosis
- Magnetic Resonance Angiography/adverse effects
- Magnetic Resonance Angiography/instrumentation
- Magnetic Resonance Angiography/methods
- Magnetic Resonance Angiography/standards
- Male
- Middle Aged
- Observer Variation
- Pain/diagnosis
- Pain/etiology
- Pain Measurement
- Sensitivity and Specificity
- Single-Blind Method
- Surveys and Questionnaires
- Tomography, X-Ray Computed/adverse effects
- Tomography, X-Ray Computed/instrumentation
- Tomography, X-Ray Computed/methods
- Tomography, X-Ray Computed/standards
- Ultrasonography, Doppler, Transcranial/adverse effects
- Ultrasonography, Doppler, Transcranial/instrumentation
- Ultrasonography, Doppler, Transcranial/methods
- Ultrasonography, Doppler, Transcranial/standards
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Affiliation(s)
- P M White
- University Department of Neurosurgery and Department of Neuroradiology, Institute of Neurological Sciences, Southern General Hospital, Glasgow G52 4TF, UK.
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305
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Johnson MR, Good CD, Penny WD, Barnes PR, Scadding JW. Lesson of the week: Playing the odds in clinical decision making: lessons from berry aneurysms undetected by magnetic resonance angiography. BMJ (CLINICAL RESEARCH ED.) 2001; 322:1347-9. [PMID: 11387186 PMCID: PMC1120432 DOI: 10.1136/bmj.322.7298.1347] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- M R Johnson
- Division of Neuroscience and Psychological Medicine, Charing Cross Hospital, London W6 8RF.
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306
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White PM, Wardlaw JM, Teasdale E, Sloss S, Cannon J, Easton V. Power transcranial Doppler ultrasound in the detection of intracranial aneurysms. Stroke 2001; 32:1291-7. [PMID: 11387489 DOI: 10.1161/01.str.32.6.1291] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE We sought to perform a large, prospective, multicenter, blinded study comparing power transcranial color duplex sonography (power TCDS) with intra-arterial digital subtraction angiography (IADSA) in the detection of intracranial aneurysms. METHODS Contemporaneous TCDS and IADSA examinations were performed in 171 subjects with suspected intracranial aneurysm. Via the temporal bone window, a 2-dimensional hand-held noncontrast transcranial duplex ultrasound imaging system was used operating in power and spectral modes. Sonographers were blinded to clinical history and results of brain CT and IADSA. RESULTS We found that 157 subjects (92%) had an adequate bone window. Sensitivity per patient was 0.78 (95% CI, 0.66 to 0.87) and 0.46 (95% CI, 0.36 to 0.56) for any anterior circulation aneurysms. Sensitivity was 0.35 (95% CI, 0.24 to 0.46) for aneurysms </=5 mm and 0.81 (95% CI, 0.62 to 0.94) for aneurysms >5 mm. Accuracy was lower for aneurysms on the cavernous and terminal internal carotid arteries, including posterior communicating artery origin (0.71; 95% CI, 0.63 to 0.79), than for those on the anterior (0.82; 95% CI, 0.74 to 0.89) or the middle cerebral arteries (0.79; 95% CI, 0.71 to 0.86). CONCLUSIONS Power TCDS is a promising, inexpensive, noninvasive test for anterior circulation intracranial aneurysms but is less sensitive per aneurysm than alternatives such as CT angiography or MR angiography. Sensitivity is poor for aneurysms </=5 mm in diameter. The internal carotid artery is the most difficult segment to interpret.
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Affiliation(s)
- P M White
- Department of Neuroradiology, Institute of Neurological Sciences, Southern General Hospital, Glasgow, UK.
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307
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White PM, Teasdale EM, Wardlaw JM, Easton V. Intracranial aneurysms: CT angiography and MR angiography for detection prospective blinded comparison in a large patient cohort. Radiology 2001; 219:739-49. [PMID: 11376263 DOI: 10.1148/radiology.219.3.r01ma16739] [Citation(s) in RCA: 233] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
PURPOSE To compare computed tomographic (CT) angiography and magnetic resonance (MR) angiography with intraarterial digital subtraction angiography (DSA) in the detection of intracranial aneurysms. MATERIALS AND METHODS One hundred forty-two patients underwent intraarterial DSA to detect aneurysms. CT angiography, three-dimensional time-of-flight MR angiography, and intraarterial DSA were performed contemporaneously. Film hard-copy images and maximum intensity projection reconstructions of the CT angiograms and MR angiograms were reviewed at different times. RESULTS The accuracy per patient for the best observer was 0.87 at CT angiography and 0.85 at MR angiography. The accuracy per aneurysm for the best observer was 0.73 at CT angiography and 0.67 at MR angiography. Differences between readers and modalities were not significant. Interobserver agreement was good: kappa value of 0.73 for CT angiography and of 0.74 for MR angiography. The sensitivity for detection of aneurysms smaller than 5 mm was 0.57 for CT angiography and 0.35 for MR angiography compared with 0.94 and 0.86, respectively, for detection of aneurysms 5 mm or larger. The accuracy of both CT angiography and MR angiography was lower for detection of internal carotid artery aneurysms compared with that at other sites. With low observer confidence, the likelihood of correct interpretation was significantly poorer. CONCLUSION CT angiography and MR angiography have limited sensitivity in the detection of small aneurysms but good interobserver agreement. There is no significant difference in diagnostic performance between the noninvasive modalities.
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Affiliation(s)
- P M White
- University Department of Neurosurgery and Department of Neuroradiology, Institute of Neurological Sciences, Southern General Hospital, Glasgow, Scotland.
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308
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Chen CC, Bellon RJ, Ogilvy CS, Putman CM. Aneurysms of the lateral spinal artery: report of two cases. Neurosurgery 2001; 48:949-53; discussion 953-4. [PMID: 11322459 DOI: 10.1097/00006123-200104000-00057] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
OBJECTIVE AND IMPORTANCE The goal of this report was to describe aneurysms arising from the lateral spinal artery. The locations of aneurysms contributing to subarachnoid hemorrhage (SAH) have been well characterized and are primarily in the circle of Willis or at the bifurcation points of the internal carotid artery or the vertebrobasilar system. Although the spinal arteries are also in direct communication with the subarachnoid space, aneurysms of these arteries that lead to SAH are rare. To date, only aneurysms of the anterior and posterior spinal arteries have been described. In this communication, we report two patients with aneurysms of the lateral spinal artery who presented with SAH. CLINICAL PRESENTATION Review of our neurointerventional database from 1997 to the present revealed two patients with lateral spinal artery aneurysms. The medical records, as well as the operative and radiological findings, were reviewed for both patients. In both cases, the lateral spinal arteries were involved as collateral pathways for occlusive vertebral lesions, suggesting hemodynamic stress as a cause. INTERVENTION Endovascular treatment was attempted in both cases and was successful in one; open surgery, with aneurysm resection, was performed in the other case. We review the vascular anatomic features of the spinal cord as they relate to the lateral spinal artery, as well as treatment options for lateral spinal artery aneurysms. CONCLUSION Lateral spinal artery aneurysms are a rare cause of SAH. Both endovascular and surgical treatment options are available.
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Affiliation(s)
- C C Chen
- Department of Interventional Neuroradiology, Massachusetts General Hospital, Harvard Medical School, Boston 02114, USA
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309
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Chen CC, Bellon RJ, Ogilvy CS, Putman CM. Aneurysms of the Lateral Spinal Artery: Report of Two Cases. Neurosurgery 2001. [DOI: 10.1227/00006123-200104000-00057] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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310
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Abstract
In this overview the results and indications of Magnetic Resonance Angiography of the intracranial vasculature will be discussed. The value of MRA will be studied in the visualisation of normal variants of the cerebral anatomy, the imaging of cerebrovascular disease, the diagnosis of aneurysms and cerebral arteriovenous malformations, the preoperative setup of cerebral tumors and the demonstration of vascular compression.
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Affiliation(s)
- G Wilms
- Department of Radiology, University Hospitals KU Leuven, Herestraat 49, 3000, Leuven, Belgium. guido.wilms@uz..kuleuven.ac.be
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311
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Ujiie H, Tamano Y, Sasaki K, Hori T. Is the aspect ratio a reliable index for predicting the rupture of a saccular aneurysm? Neurosurgery 2001; 48:495-502; discussion 502-3. [PMID: 11270538 DOI: 10.1097/00006123-200103000-00007] [Citation(s) in RCA: 264] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
OBJECTIVE The present retrospective study was undertaken to prove the reliability of the aspect ratio (aneurysm depth to aneurysm neck width) for predicting an aneurysmal rupture. The aspect ratio is considered a better geometric index than aneurysm size for determining the intra-aneurysmal blood flow. METHODS We measured the aspect ratios and the sizes of aneurysms, as determined by examining angiographic films magnified 1.4x, in 129 patients with ruptured aneurysms and in 72 patients with 78 unruptured aneurysms. After categorizing the aneurysms into four groups on the basis of their locations (aneurysms of the anterior communicating artery, middle cerebral artery, internal carotid artery-posterior communicating artery [ICA-PComA], and other aneurysms), a statistical analysis of ruptured and unruptured aneurysms was performed. RESULTS The mean aneurysm size was found to be statistically significant in the aneurysms at the ICA-PComA and in locations excluding the anterior communicating artery, the middle cerebral artery, and the ICA-PComA. However, the mean aspect ratio was statistically significant at all four locations. In patients with ruptured aneurysms, no ruptured aneurysms with an aspect ratio of less than 1.0 were found. The distribution of the ruptured group versus the unruptured group with an aspect ratio of less than 1.6 at each location was 13 versus 79%, respectively, at the anterior communicating artery, 11 versus 58% at the middle cerebral artery, 11% versus 85% at the ICA-PComA, and 7 versus 81% at other locations. CONCLUSION The aspect ratio between ruptured aneurysms and unruptured aneurysms was found to be statistically significant, and almost 80% of the ruptured aneurysms showed an aspect ratio of more than 1.6, whereas almost 90% of the unruptured aneurysms showed an aspect ratio of less than 1.6. This study therefore suggests that the aspect ratio may be useful in predicting imminent aneurysmal ruptures.
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Affiliation(s)
- H Ujiie
- Department of Neurosurgery, Neurological Institute, Tokyo Women's Medical University, Japan.
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312
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Abstract
The incidence of subarachnoid haemorrhage (SAH) is stable, at around six cases per 100 000 patient years. Any apparent decrease is attributable to a higher rate of CT scanning, by which other haemorrhagic conditions are excluded. Most patients are <60 years of age. Risk factors are the same as for stroke in general; genetic factors operate in only a minority. Case fatality is approximately 50% overall (including pre-hospital deaths) and one-third of survivors remain dependent. Sudden, explosive headache is a cardinal but non-specific feature in the diagnosis of SAH: in general practice, the cause is innocuous in nine out of 10 patients in whom this is the only symptom. CT scanning is mandatory in all, to be followed by (delayed) lumbar puncture if CT is negative. The cause of SAH is a ruptured aneurysm in 85% of cases, non-aneurysmal perimesencephalic haemorrhage (with excellent prognosis) in 10%, and a variety of rare conditions in 5%. Catheter angiography for detecting aneurysms is gradually being replaced by CT angiography. A poor clinical condition on admission may be caused by a remediable complication of the initial bleed or a recurrent haemorrhage in the form of intracranial haematoma, acute hydrocephalus or global brain ischaemia. Occlusion of the aneurysm effectively prevents rebleeding, but there is a dearth of controlled trials assessing the relative benefits of early operation (within 3 days) versus late operation (day 10-12), or that of endovascular treatment versus any operation. Antifibrinolytic drugs reduce the risk of rebleeding, but do not improve overall outcome. Measures of proven value in decreasing the risk of delayed cerebral ischaemia are a liberal supply of fluids, avoidance of antihypertensive drugs and administration of nimodipine. Once ischaemia has occurred, treatment regimens such as a combination of induced hypertension and hypervolaemia, or transluminal angioplasty, are plausible, but of unproven benefit.
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Affiliation(s)
- J van Gijn
- Department of Neurology, University Medical Centre, Utrecht, The Netherlands.
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313
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Ruigrok YM, Rinkel GJ, Buskens E, Velthuis BK, van Gijn J. Perimesencephalic hemorrhage and CT angiography: A decision analysis. Stroke 2000; 31:2976-83. [PMID: 11108759 DOI: 10.1161/01.str.31.12.2976] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE The method of choice for detecting or excluding a vertebrobasilar aneurysm still is a matter of debate in patients with a characteristically perimesencephalic pattern of subarachnoid hemorrhage (SAH) on CT. We used decision analysis to compare possible diagnostic strategies in these patients. METHODS A decision analytic model was developed to evaluate the effect of 4 different diagnostic strategies following a perimesencephalic pattern of SAH on CT: 1, no further investigation; 2, digital subtraction angiography (DSA) by catheter; 3, CT angiography as initial modality, not followed by DSA if negative; and 4, CT angiography as initial modality, followed by DSA. We used a 4% prevalence of a vertebrobasilar aneurysm given a perimesencephalic pattern of hemorrhage, a 97% sensitivity and specificity of CT angiography, and a 99.5% sensitivity and 100% specificity of DSA. In a prospectively collected series, the complication rate from DSA in patients with a perimesencephalic pattern of hemorrhage was 2.6%. We calculated the expected utility of each of the 4 diagnostic options and used sensitivity analyses to examine the influence of the plausible ranges of the various estimates used. RESULTS The expected utilities were 99.09 for CT angiography only, 98.96 for no further investigation, 98.22 for DSA, and 96.34 for CT angiography plus DSA. The results of the sensitivity analysis indicate that over a wide range of assumptions, CT angiography only is the most beneficial option. Only when the complication rate of catheter angiography is <0.2% is DSA the preferred strategy. CONCLUSIONS Our decision analysis shows that in patients with a perimesencephalic pattern of hemorrhage on CT, CT angiography only is the best diagnostic strategy. DSA can be omitted in patients with a perimesencephalic pattern of hemorrhage and a negative CT angiogram.
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Affiliation(s)
- Y M Ruigrok
- Department of Neurology, University Medical Center Utrecht, (Netherlands).
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314
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Mitchell P, Jakubowski J. Estimate of the maximum time interval between formation of cerebral aneurysm and rupture. J Neurol Neurosurg Psychiatry 2000; 69:760-7. [PMID: 11080228 PMCID: PMC1737163 DOI: 10.1136/jnnp.69.6.760] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
The recent publication of the results of the international study on unruptured intracranial aneurysms highlighted a paradox: there do not seem to be enough unruptured aneurysms in the population to account for the observed incidence of subarachnoid haemorrhage. Some authors have suggested that the answer to this paradox is that most aneurysms that bleed do so shortly after formation. This would mean that the bulk of subarachnoid haemorrhages come from recently formed rather than long standing aneurysms. This paradox and proposed answer are examined. The available statistics on the incidence of subarachnoid haemorrhage, the prevalence of unruptured aneurysms, and the risk of bleeding from unruptured aneurysms are used to place a maximum on the time interval between aneurysm formation and rupture. For aneurysms less than 10 mm in diameter in persons with no history of subarachnoid haemorrhage, an estimate of less than 42 weeks was made. The null hypothesis that such aneurysms pose a constant risk with time is rejected with p <10(-9). In larger aneurysms the risk seems to be constant with time.
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Affiliation(s)
- P Mitchell
- Department of Neurological Surgery, N Floor, Royal Hallamshire Hospital, Glossop Road, Sheffield S10 2JF, UK.
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