Neurology -- Correspondence for Ment et al., 58 (12) 1726-1738

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Correspondence published:

Reply to Letter ot the Editor: Laura R Ment, Henrietta S. Bada, Patrick Barnes, P. Ellen Grant, Deborah Hirtz, LuAnn Papile, Jennifer Pinto-Martin and Thomas L. Slovis (16 August 2002)

Practice parameter: Neuroimaging of the neonate: Report of the Quality Standards Subcommittee of the: A James Barkovich, Steven Miller, Donna Ferriero and Faye Silverstein (16 August 2002)

Reply to Letter ot the Editor 16 August 2002

Laura R Ment
Yale University School of Medicine,
Henrietta S. Bada, Patrick Barnes, P. Ellen Grant, Deborah Hirtz, LuAnn Papile, Jennifer Pinto-Martin and Thomas L. Slovis
Send Correspondence to journal:
Re: Reply to Letter ot the Editor

laura.ment{at}yale.edu Laura R Ment, et al.

The authors thank Drs. Miller, Ferriero, Barkovich and Silverstein for their thoughtful comments. As those who work in newborn intensive care units know all too well, survival rates for both very low birth weight preterm infants and critically ill term neonates have markedly increased – yet the incidence of disability in these pediatric populations has not changed during the past two decades.
Neuroimaging is critical for both care and prognosis in newborn intensive care. The authors of the parameter join Miller et al. in celebrating the excitement and promise of the full range of magnetic resonance imaging as it is applied to the tiniest and most vulnerable of our patient populations. Traditional MRI studies, DWI, functional MRI and volumetric strategies have all been utilized to demonstrate the impact of preterm birth on the developing brain, and studies in older prematurely born children suggest that imaging changes correlate with functional ones. [1, 2, 3] The hope is now that these techniques may not only contribute early evidence of injury but will also provide prognostic information for physicians, parents and caregivers alike.
The ability of MR strategies to provide diagnostic information in the encephalopathic term neonate is significant, and the parameter recommends MRI, single voxel MRS and DWI between days 2 and 8 in all encephalopathic infants without evidence for hemorrhagic brain injury. While MRS may be useful on the first day of life, DWI appears to be mores sensitive after that time, and further studies are needed to determine topologic and age- matched normative values for the former technique. [4, 6] The authors are pleased to note the very recent publication by Miller et al., which assesses the complicated yet important roles of proton MRS and socioeconomic factors to predict neurodevelopmental outcome at age 30 months in 37 encephalopathic term infants. [5] In this study, MRI and MRS were performed at a median age of 6 days (range 2 – 13 days), consistent with the parameter recommendations.
The Practice Parameter is based on published literature. As data become available in the future, the recommendations contained therein will be updated and revised as indicated. Neuroimaging is an essential component of Newborn Special Care, and there is much to be learned at the interface of biomedical engineering and clinical care.
References:
1) Peterson BS, Vohr G, Cannistraci CJ. Et al. Regional brain volume abnormalities and long-term cognitive outcome in preterm infants. JAMA 2000;284:1939-1947.
2) Olsen P, Paakko E, Vainionpaa L, Pyhtinen J, Jarvelin M-R. Magnetic resonance imaging of periventricular leukomalacia and its clinical correlation in children. Ann Neurol 1997;41:754-761.
3) Peterson BS, Vohr BR, Kane M, et al. A functional MRI study of language processing and cognitive outcome in prematurely born children. Pediatric 2002; in press.
4) Barkovich AJ, Westmark KD, Bedi HS, Partridge JC, Ferriero DM, Vigneron D. Proton spectroscopy and diffusion imaging of the first day of life after perinatal asphyxia: Preliminary report. AJNR Am J Neurorad 2001;22:1786-1794.
5) Miller SP, Newton N, Ferriero DM, et al. Predictors of 30-month outcome after perinatal depression: Role of proton MRS and socioeconomic factors. Pediatr Res 2002;52:71-77.
6) Sie LT, van der Knapp MS, van Wezel-Meijler G. Taets van Amerongen AH, Lafeber HN, Valk J. Early MR features of hypoxic-ischemia brain injury in neonates with periventricular densities on sonograms. AJNR Am J Neuroradiol 2000;21:852-861.

Practice parameter: Neuroimaging of the neonate: Report of the Quality Standards Subcommittee of the 16 August 2002

A James Barkovich
University of California San Francisco,
Steven Miller, Donna Ferriero and Faye Silverstein
Send Correspondence to journal:
Re: Practice parameter: Neuroimaging of the neonate: Report of the Quality Standards Subcommittee of the

jimb{at}radiology.ucsf.edu A James Barkovich, et al.

Ment et al. should be commended for undertaking the onerous task of developing neuroimaging guidelines for the neonate. [1] This task is made difficult by the heterogeneous definitions of neonatal brain injury, different applications of the same technologies, and widely discrepant study designs used since 1990 in neonatal neuroimaging studies. The authors systematically reviewed this extensive literature and distilled a number of practice parameters.
With respect to the premature newborn, this practice parameter must be interpreted with caution, in view of the considerable advances in the MR imaging of the premature newborn's brain that have been made in the past 5 years. We and several other colleagues have been enrolling premature newborns in prospective studies to determine the relationship between MRI findings and neurodevelopmental outcome. As a result of these studies the spectrum of white matter injury detectable by MRI is being determined and the effects of early white matter injury on subsequent brain development are being clarified. [2, 3, 4, 5, 6, 7, 8] It is becoming increasingly clear that MRI detects lesions that are not detected by ultrasound and that these lesions are associated with abnormal brain development measured in a variety of ways. Furthermore, advanced MR techniques, such as diffusion tensor imaging and MR spectroscopic imaging offer the exciting possibility of detecting white matter injury at a time when intervention is at least theoretically possible. [9, 10, 11] However, to have meaningful neurodevelopmental follow-up data, cohorts enrolled in study must reach at least 30 months of age. The wealth of exciting preliminary data supporting the role of MRI in neuroimaging the premature newborn presented at meetings in abstract form at the Society for Pediatric Research and the International Society of Magnetic Resonance in Medicine this year (2002) suggests that the literature will soon contain the neurodevelopmental follow-up data that we are currently lacking. [12, 13]
We recognize that the issue of “when” to establish guidelines is difficult as the speed of scientific discovery continues to advance and there is always new information on the horizon. Yet it is important to recognize the potential bias of practice parameters in favoring techniques that have been in use for a longer period of time, at the cost of novel techniques that may be advantageous. During any given period of time, older techniques are published more frequently as there is significant lag -time until new techniques are adequately validated and accepted in the literature. This is particularly true of MRI and neuroimaging the premature newborn.
We congratulate the authors on their work with respect to neuroimaging of the term newborn. However, the authors suggest that early CT should be used to exclude hemorrhage, and MRI should be performed later in the first postnatal week to establish pattern of injury due to asphyxial damage. Neonatal encephalopathy is more often due to prenatal causes such as inborn errors of metabolism, cerebral dysgenesis, or intrauterine infection. [14] MRI helps to narrow the differential diagnosis in the evaluation of an encephalopathic neonate who is not dysmorphic but might have an underlying neurogenetic, neurovascular or inflammatory disease requiring intervention. As the first step in caring for an encephalopathic newborn is establishing the diagnosis, MRI early in the first week of life is the diagnostic test of choice.
Equally important, in addition to helping establish a diagnosis in the encephalopathic newborn, these MR techniques, in particular MR spectroscopy performed at the same time as the MRI, can then provide invaluable prognostic information for the care of these newborns. The valuable prognostic capabilities of MRI and MRS were well illustrated by the authors. Unfortunately, CT does not compare favorably with MRI for confirming the diagnosis of hypoxic-ischemic brain injury or providing prognostic information.
We sincerely hope that this practice parameter in defining clinical guidelines will not be misused to limit clinical access and insurance coverage for optimal imaging modalities for newborns.
Finally, we would like to commend Ment et al. for highlighting the need of future research related to imaging the newborn brain.
References:
1. Ment LR, Bada, MD, Barnes P, et al. Practice parameter: Neuroimaging of the neonate. Report of the Quality Standards Subcommittee of the American Academy of Neurology and the Practice Committee of the Child Neurology Society. Neurology 2002;58:1726-1738.
2. Hüppi PS, Warfield S, Kikinis R. et al. Quantitative magnetic resonance imaging of brain development in premature and mature newborns. Annals of Neurology 1998;43:224-235.
3. Maalouf EF, Duggan PJ, Rutherford MA, et al. Magnetic resonance imaging of the brain in a cohort of extremely preterm infants. Journal of Pediatrics 1999;135:351-357.
4. Maalouf EF, Dugan PJ, Counsell SJ, et al. Comparison of findings on cranial ultrasound and magnetic resonance imaging in preterm infants. Pediatrics 2001;107:719-727.
5. van Wezel-Meijler G, van der Knaap MS, Sie LT, et al. Magnetic resonance imaging of the brain in premature infants during the neonatal period. Normal phenomena and reflection of mild ultrasound abnormalities. Neuropediatrics 1998;29:89-96.
6. Inder TE, Hüppi PS, Warfield S, et al. Periventricular white matter injury in the premature infant is followed by reduced cerebral cortical gray matter volume at term. Annals of Neurology 1999;46:755-760.
7. Groenendaal F, van der Grond J, Eken P, et al. Early cerebral proton MRS and neurodevelopmental outcome in infants with cystic leukomalacia. Developmental Medicine and Child Neurology 1997;39:373-379.
8. Sie LT, van der Knapp MS, van Wezel-Meijler G. Taets van Amerongen AH, Lafeber HN, Valk J. Early MR features of hypoxic-ischemic brain injury in neonates with periventricular densities on sonograms. AJNR Am J Neuroradiol 2000;21:852-861.
9. Vigneron DB, Barkovich AJ, Noworolski SM, et al. Three-dimensional proton MR spectroscopic imaging of premature and term neonates. AJNR Am J Neuroradiol 2001;22:1424-1433.
10.Hüppi PS, Maier SE, Peled S, et al. Micostructural development of human newborn cerebral white matter assessed in vivo by diffusion tensor magnetic resonance imaging. Pediatric Research 1998;44:584-590.
11.Inder T, Hüppi PS, Zientara GP, et al. Early detection of periventricular leukomalacia by diffusion-weighted magnetic resonance imaging techniques [see comments]. Journal of Pediatrics 1999;134:631-634.
12.Pediatric Academic Societies’ Annual Meeting. Program Issue. Pediatric Research 2002;51:438A-440A.
13.Proceedings of the ISMRM, 10th Annual Meeting (Honolulu), 2002.
14.Nelson KB, Grether JK. Selection of neonates for neuroprotective therapies: One set of criteria applied to a population. Arch Pediatr Adolesc Med 1999;153:393-398.