(Stroke. 2002;33:1280.)
© 2002 American Heart Association, Inc.
Original Contributions |
From the Service de Radiologie (B.H.), Service de Neurologie, Département de Pédiatrie (M.T.), and Service de Neuroradiologie (G.R., P.L.), Hôpital Bicêtre, Université Paris XI, Le Kremlin Bicêtre, France; and Service de Neurologie Pédiatrique, Unité de Neurologie et du Développement, Cliniques universitaires Saint Luc, Université Catholique de Louvain, Brussels, Belgium (G.S.).
Correspondce to Béatrice Husson, MD, Service de Radiopédiatrie, Centre Hospitalier Universitaire de Bicêtre, 78 rue du Général Leclerc, 94275 Le Kremlin Bicêtre Cédex, France. E-mail beatrice.husson{at}bct.ap-hop-paris.fr
| Abstract |
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Methods Twenty-four children presenting with 26 infarcts were studied. All were examined with cerebral MRI and MRA and with CA. The interval between CA and MRA was <3 days for most of the patients.
Results Arterial lesions were detected in all but 2 children. They were located in the major cerebral arteries, predominantly in the anterior circulation (85% of cases). All lesions shown by CA were present on MRA (19 cases). Patients with no lesion on MRA had normal CA (2 cases). Associated distal vascular lesions and degree of arterial stenosis were more accurately detected with CA.
Conclusions MRA is sensitive enough to provide an adequate initial evaluation of arterial brain disease in childhood.
Key Words: angiography child magnetic resonance angiography stroke
| Introduction |
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| Subjects and Methods |
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To determine the accuracy of MRA in the analysis of large, medium, and small arteries, MRA and CA were interpreted by 2 investigators who were not aware of each others results. On the basis of CA data, the following terms were used to describe the various vascular lesions: occlusion was defined as a total obstruction of a vessel, focal stenosis as a short and regular narrowing of a vessel, severe stenosis as a succession of tight stenoses leading often to a "string of beads" appearance, irregular stenosis as nonocclusive segmental irregularities of the arterial wall, endoluminal defect as a segmental lack of blood flow, and ectasia as arterial enlargement.
CA was performed under general anesthesia by transfemoral selective catheterization of internal carotid arteries (ICA) and vertebral arteries after informed consent was obtained from the parents. We did not observe any complications. MRI and MRA were conducted with a 1.5-T Siemens Magnetom unit. Light sedation (sodium pentobarbital, 5 mg/kg, rectal administration) was required only for children younger than 6 years. MRI was performed with T1- and T2-weighted axial and coronal sequences. MRA of the intracranial circulation was performed with the use of a 3-dimensional time-of-flight fast imaging with steady state precession sequence with repetition time/echo time=35/6 ms, flip angle=20°, and axial volume with 50 slices 0.8 mm in thickness. Transfer of magnetization was used with a 256x256 matrix and field of view of 200 mm. The data sets were reconstructed with a maximum intensity projection algorithm. In addition, cervical MRA (5 patients) was performed with a 3-dimensional time-of-flight sequence with the use of multiple overlapping thin-slab acquisition when cervical trauma was suspected or when flow was not visualized in the ICA with MRA.
| Results |
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Detection of Arterial Lesions
The MRA and CA data for the large arteries were similar in the 26 strokes. These patients had either anomalies of the large cerebral arteries (anterior cerebral artery [ACA], MCA, posterior cerebral artery [PCA], ICA, and basilar artery; n=24) or normal examinations (n=2 [patients 11 and 12]). Two patients had anomalies involving all major vessels of the circle of Willis (patients 1 and 9). Nine had abnormalities involving the supraclinoid ICA (distal ICA) extending to the initial segment of the MCA (n=9) and ACA (n=5) (Figure 1). Nine children had focal lesions, located in the cervical ICA (n=1), in the horizontal segment of the MCA (n=5), in the initial segment of the PCA (n=1), and in the basilar artery (n=2). In 3 cases (patients 17, 20, 24) with a distal occlusion of a supraclinoid ICA, MRA as well as CA showed a severe decrease of flow in the cervical segment of the ICA (Figure 2).
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For all 10 patients with parenchymal infarcts limited to the region of the deep gray nuclei, MRA gave the same result as CA in detecting the arterial lesions. Both techniques showed either focal anomalies of MCA (n=4; patients 7, 10, 22, 23), dissection of cervical ICA (n=1; patient 4), or extended lesions of ICA and MCA (n=3; patients 14, 18, 20). Two patients had normal MRA and CA.
In 9 children (34%) CA detected anomalies of small arteries not visible on MRA. These anomalies were located on distal MCA branches and were associated in all the patients with lesions of the horizontal portion of the MCA detected with MRA.
Characterization of Arterial Lesions
Among the 24 infarcts with intracranial or cervical vascular lesions, MRA and CA provided identical information in 18 cases (75%). Arteriographic occlusions, endoluminal defects (Figure 3), and multiple ectasia were diagnosed with MRA as well as CA.
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In 6 cases (25%), MRA and CA were discordant (Table 2). In all of these cases arteriographic stenosis was overestimated with MRA. Irregular (patient 18) and focal stenosis (patient 22) appeared as severe stenosis on MRA. In 4 patients, a severe stenosis appeared as an occlusion on MRA (patients 13, 17, 21, 24).
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The characteristics of arterial lesions studied by MRA were specific enough to pinpoint the common etiopathological conditions. Two of our 24 patients (8%) had moyamoya syndrome with bilateral ICA lesions and a basal neovascular network that was diagnosed by MRA as well as by CA. Dissection of the vertebral or cervical carotid arteries was detected in 2 patients (8%). For these 2 patients a pseudoaneurysm was present, one seen on CA and MRA at days 20 and 21, respectively, after the stroke (patient 5), the other detected by MRA performed 6 days after CA, which showed a severe stenosis of the cervical segment of an ICA (patient 4, Figure 4). Nineteen strokes (73%) remained idiopathic; 5 of the children had recently had chickenpox.
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| Discussion |
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Some studies have already assessed the value of MRA for the visualization of the intracranial circulation in childhood.28 In a series of 31 pediatric brain infarcts confirmed by MRI, Zimmerman et al5 observed MRA anomalies in 62% of cases. Using MRA in a series of 24 children with parenchymal infarcts, Wiznitzer and Masaryk6 reported abnormalities in the corresponding arteries in 75% of cases. None of these studies compared CA and MRA. Lee et al7 performed such comparison, but the interval between the 2 explorations was not specified. In this series of 13 children with stroke, the authors showed that MRA was concordant with CA in 100% of cases for the localization of vascular lesions in large- to medium-caliber intracranial arteries. Rollins et al8 also compared MRA and CA and found that the positive predictive value of MRA for arteriopathy was 100%. MRA was as reliable as CA in the detection of stenotic or occlusive diseases of the ICA and MCA. Our findings confirm an excellent correlation between CA and MRA for the detection and location of intracerebral arterial lesions, although the characterization of the type of lesion remains somewhat limited with MRA (circumferential clefts, intimal flaps, intraluminal thrombi, or tapering of MCA branches). As previously shown, in several series of strokes in childhood investigated with CA,710 the most common sites of arterial disease are the distal ICA or the proximal MCA. In our series, the same locations were observed in 74% of the cases. The study of Rollins et al8 of distal ICA lesions raised doubts concerning the p2recision of MRA compared with CA. This suspected limitation is apparently due to a well-recognized artifact caused by signal loss in a large vessel in regions of complex flow such as the internal carotid siphon or the bifurcation of the common and internal carotid arteries.4,6,7,11,12 The use of 3-dimensional time-of-flight sequences with thin slices (<1 mm) and a 512 matrix to decrease voxels, combined with analysis of the source images, enables differentiation between an artifact and a vascular lesion. Taking into account these technical considerations, we improved the images in our patients, leading to the elimination of any discordant results by MRA compared with CA in exploring the distal ICA.
Ten children of our series (42%) had infarcts limited to the basal ganglia. Brower et al13 described the characteristics of this entity, which is a frequent association with arterial stroke in childhood. In our study both MRA and CA showed the same lesions in this subgroup. It is therefore inferable that MRA is comparable to CA in detecting one of the most frequent intracranial arterial lesions associated with stroke in children. Furthermore, MRA was as efficient as CA in detecting the main etiologies of arterial diseases of the brain in childhood, particularly moyamoya, extracranial dissection, and idiopathic arteriopathy, such as transient cerebral arteriopathy.10 These data are in agreement with several studies reporting the usefulness of MRA in the diagnosis of cervical dissection,1416 although confident diagnosis or exclusion may require CA.17 Likewise, Yamada et al11 reported accurate diagnosis and evaluation of moyamoya by MRA. CA was reserved for cases in which surgical revascularization was planned. However, in particular cases, such as intracranial dissection, the spatial resolution of MRA, which is inferior to CA, can lead to an imprecise description of the nature of the lesion. Furthermore, the extent of collateral flow via leptomeningeal anastomoses cannot be judged by MRA.
Other pitfalls, limitations, and technical points must be considered when MRA is used. In 3 patients from our series, a signal void on the cervical ICA proximal to a severe intracranial lesion raised some difficulties concerning the precise diagnosis. It is known that slow blood flow is difficult to visualize with a 3-dimensional time-of-flight sequence.4,5 In situations in which the underlying mechanism is doubtful, such as slow blood flow proximal to a distal stenosis or an intraluminal defect, a Doppler examination of the cervical vessels may resolve the diagnostic problem. If this sonographic exploration fails, CA should be considered. Another known limitation of MRA is its lack of sensitivity in the detection of small-vessel diseases.2,3,68,14,17,18 Some authors3,12,19 have noted the utility of the technique of magnetization transfer with increased signal-to-noise ratio, which improves small-vessel detection. Additionally, the use of intravenous paramagnetic contrast to increase the signal of blood in vessels may allow better definition of small vessels.3,7 Furthermore, the sensitivity of MRA may be enhanced when a 512 matrix is used.7 However, the indication for investigation of the small cerebral vessels in children is restricted to a small fraction of patients because most ischemic strokes in childhood are related to lesions involving large arteries. CA is indicated for the investigation of lesions distal to small vessels, for instance, to make the distinction between embolic disease and inflammatory processes, such as isolated angiitis of the central nervous system.20 Another widely noted limitation of MRA is the overestimation of stenosis,2,3,6,18,21 observed in 25% of our patients. A precise quantification of stenosis, for instance, in carotid artery lesions, is important in adulthood in making therapeutic decisions. In childhood, such quantification currently seems to be less important since the degree of stenosis is not recognized as a determinant parameter in therapeutic decisions.
In conclusion, within the diagnostic framework we studied, MRA is sensitive enough to provide an adequate and most often sufficient evaluation in the initial stage of arterial brain diseases in childhood. However, CA should be considered in situations in which MRA is normal, small-artery diseases are suspected, or uncertainties about the differential diagnosis of ICA lesions persist and for an accurate assessment of the effect of therapeutic trials on the arterial wall.
| Acknowledgments |
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Received July 5, 2001; revision received December 19, 2001; accepted January 30, 2002.
| References |
|---|
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2.
Volgl TJ, Balzer JO, Stemmler J, Bergman C, Egger E, Lissner J. MR angiography in children with cerebral neurovascular diseases. AJR Am J Roentgenol. 1992; 159: 817823.
3. Koelfen W, Wentz U, Freund M, Schultze C. Magnetic resonance angiography in 140 neuropediatric patients. Pediatr Neurol. 1995; 12: 3138.[CrossRef][Medline] [Order article via Infotrieve]
4. Maas K, Barkovich AJ, Dong L, Edwards MSB, Piecuch RE, Charlton V. Selected indications for and applications of magnetic resonance angiography in children. Pediatr Neurosurg. 1994; 20: 113125.[Medline] [Order article via Infotrieve]
5. Zimmerman RA, Bogdan AR, Gusnard DA. Pediatric magnetic resonance angiography: assessment of stroke. Cardiovasc Intervent Radiol. 1992; 15: 6064.[Medline] [Order article via Infotrieve]
6. Wiznitzer M, Masaryk TJ. Cerebrovascular abnormalities in pediatric stroke: assessment using parenchymal and angiographic magnetic resonance imaging. Ann Neurol. 1991; 29: 585589.[CrossRef][Medline] [Order article via Infotrieve]
7. Lee BCP, Park TS, Kaufman BA. MR angiography in pediatric neurological disorders. Pediatr Radiol. 1995; 25: 409419.[CrossRef][Medline] [Order article via Infotrieve]
8.
Rollins N, Dowling M, Booth T, Purdy P. Idiopathic ischemic cerebral infarction in childhood: depiction of arterial abnormalities by MR angiography and catheter angiography. AJNR Am J Neuroradiol. 2000; 21: 549556.
9. Harwood-Nash DC, McDonald P, Argent W. Cerebral arterial disease in children. AJR Am J Roentgenol. 1971; 111: 672686.[Abstract]
10.
Chabrier S, Rodesch G, Lasjaunias P, Tardieu M, Landrieu P, Sebire G. Transient cerebral arteriopathy: a disorder recognized by serial angiograms in children with stroke. J Child Neurol. 1998; 13: 2732.
11.
Yamada I, Suzuki S, Matsushima Y. Moyamoya disease: comparison of assessment with MR angiography and MR imaging versus conventional angiography. Radiology. 1995; 196: 211218.
12.
Edelman RR, Ahn SS, Chien D, LI W, Goldmann A, Mantello M, Kramer J, Kleefield J. Improved time-of-flight MR angiography of the brain with magnetization transfer contrast. Radiology. 1992; 184: 395399.
13.
Brower MC, Rollins N, Roach ES. Basal ganglia and thalamic infarction in children: cause and clinical features. Arch Neurol. 1996; 53: 12521256.
14.
Mann CI, Dietrich RB, Schrader MT, Peck WW, Demos DS, Bradley WG Jr. Posttraumatic carotid artery dissection in children: evaluation with MR angiography. AJR Am J Roentgenol. 1993; 160: 134136.
15. Patel H, Smith RR, Garg BP. Spontaneous extracranial carotid artery dissection in children. Pediatr Neurol. 1995; 13: 5560.[CrossRef][Medline] [Order article via Infotrieve]
16. Khurana DS, Bonnemann CG, Dooling EC, Ouellette EM, Buonanno F. Vertebral artery dissection: issues in diagnosis and management. Pediatr Neurol. 1996; 14: 255258.[CrossRef][Medline] [Order article via Infotrieve]
17. Ganesan V, Savvy L, Chong WK, Kirkham FJ. Conventional cerebral angiography in the investigation of children with ischaemic stroke. Pediatr Neurol. 1999; 20: 3842.[CrossRef][Medline] [Order article via Infotrieve]
18. Brunereau L, Bousson V, Arrivé L, Lévy C, Marsot-Dupuch K, Tubiana JM. Artefacts en angiographie par résonance magnétique. J Radiol. 1998; 79: 849859.[Medline] [Order article via Infotrieve]
19. Dousset V, Franconi JM, Degrèze P, Balderrama J, Lexa F, Caillé JM. Use of magnetisation transfer contrast to improve cerebral 3 D MR angiography. Neuroradiology. 1994; 36: 188192.[CrossRef][Medline] [Order article via Infotrieve]
20.
Lanthier S, Lortie A, Michaud J, Laxer R, Jay V, deVeber G. Isolated angiitis of the CNS in children. Neurology. 2001; 56: 837842.
21. Johnson BA, Heiserman JE, Drayer BP, Keller PJ. Intracranial MR angiography: its role in the integrated approach to brain infarction. AJNR Am J Neuroradiol. 1994; 15: 901908.[Abstract]
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