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ARTICLES: Heather J. Fullerton, Yvonne W. Wu, Stephen Sidney, and S. Claiborne Johnston Risk of Recurrent Childhood Arterial Ischemic Stroke in a Population-Based Cohort: The Importance of Cerebrovascular Imaging Pediatrics 2007; 119: 495-501 [Abstract] [Full text] [PDF]

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The importance of high quality MR Angiography in neonatal and pediatric cerebrovascular imaging.

Christina Malamateniou, Frances M Cowan, Mary A Rutherford, Jo V Hajnal, Imaging Sciences Department, Imperial College London   (24 April 2007)

The importance of high quality MR Angiography in neonatal and pediatric cerebrovascular imaging. 24 April 2007
Christina Malamateniou, Lecturer in Medical Imaging Division of Medical Imaging, University of Liverpool and ISD, Imperial College London, Frances M Cowan, Mary A Rutherford, Jo V Hajnal, Imaging Sciences Department, Imperial College London Send letter to journal: Re: The importance of high quality MR Angiography in neonatal and pediatric cerebrovascular imaging. chris06{at}liverpool.ac.uk Christina Malamateniou, et al.	We read with great interest the paper of Fullerton et al in the March 2007 Pediatrics issue. The authors emphasized the importance of cerebrovascular imaging in childhood arterial ischemic stroke as a strong predictor of recurrence(1). They concluded that, notwithstanding its clinical value, cerebrovascular imaging is not commonly performed but suggested that “Magnetic resonance angiography is probably a reasonable first step”. We are very supportive of this suggestion and would like to highlight the following: Magnetic resonance angiography (MRA) is non-invasive, does not involve radiation and can produce high quality vascular images without contrast, if a flow dependent technique, either a Time-of-Flight (TOF) or a Phase-Contrast (PC) MRA, is used. Therefore MRA is well suited for this population. However MRA has some limitations, such as slow flow saturation and lack of sensitivity to detect small vessels(2), highlighted by previous studies. In our experience problematic visualisation of the small peripheral vessels in most neonatal and pediatric cerebrovascular imaging studies stems mainly from the use of standard adult protocols and preset commercially available sequences instead of neonatal and pediatric dedicated MRA protocols (3, 4). In our study in a neonatal population we modified the adult preset sequence into an optimised one that took into account the specific neonatal anatomic and physiological characteristics: smaller cerebral vessels, slower blood flow(5) and necessity for fast scans to avoid motion artefacts. We addressed those characteristics by using higher true spatial resolution of 0.6x0.6x0.6mm3 to compensate for the smaller vessel size, multiple overlapping thin slab acquisition to minimise slow flow saturation and parallel imaging to maintain reasonable scanning times of approximately 5 minutes helping us achieve motion-free images(6). This optimised protocol significantly improved peripheral vessel visualisation both by qualitative and quantitative measures of image quality. To conclude, we would like to highlight that MRA can be the way forward in non invasive pediatric and neonatal cerebrovascular imaging to monitor both disease but also normal vessel development only when it is used in its full potential; this should involve thorough optimisation of the MRA protocols based on the anatomical and physiological features of the target population before embarking on clinical trials. References 1. Fullerton HJ et al, Pediatrics 2007 2. Busson B et al, Stroke, 2002 3. Kuker W et al, Child’s Nervous System, 2004 4. Allison JW et al, Radiographics, 1994 5. d’Orey C et al, Journal of Perinatal Medicine 1999 6. Malamateniou C et al, Neuroimage, 2006 Conflict of Interest: None declared

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