Magnetic resonance techniques in the evaluation of the newborn brain

MR imaging provides unequaled sensitivity as compared with US or CT scanning for evaluating developmental changes and pathologic processes in the newborn brain. Myelination can be assessed qualitatively and quantitatively using newer 3D-MR imaging methods. MR imaging provides a much clearer delineation of many developmental disorders, including anomalies of migration and organization, as well as a variety of metabolic disorders and congenital infections. Neonatal intracranial hemorrhage is detected in all its locations by MR imaging. The timing of the hemorrhage is a unique feature of MR imaging. Venous thrombosis also can be identified by MR imaging and confirmed with MR angiography. HIE is the major cause of potentially preventable or reversible brain injury that results in considerable long-term neurologic morbidity. Early detection is crucial for interventions aimed at preventing or reversing ongoing injury. DWI can show early changes at the cellular level that are not detectable by any other imaging modality. MR spectroscopy has further opened the possibility of studying the metabolic mechanisms that define the pathophysiologic events taking place in neonatal brain injury. Both 31P-MR spectroscopy, as a marker of the acute changes in energy metabolism, and 1H-MR spectroscopy, with the measurement of lactate and the excitotoxic aminoacids glutamate and glutamine, have enabled us to study the early and late effects of insults to the newborn brain in a noninvasive fashion. Studies performed to determine the predictive value of MR spectroscopy for later neurodevelopmental outcome after HIE have shown promising results but need further evaluation on larger patient samples. The potential use of these methods in the evaluation of early neuroprotective treatment regimens in the newborn remains to be determined.     

Diagnostic imaging for pediatric scrotal disorders

Classification of pediatric scrotal disorders into three typical clinical manifestations--acute scrotal disorders, scrotal masses, and cryptorchidism--provides a practical basis for evaluation with the most commonly used modalities--sonography, scintigraphy, and magnetic resonance (MR) imaging. Acute scrotal disorders of children include acute epididymitis, torsion of an appendix testis or appendix epididymis, and torsion of the spermatic cord. Either scintigraphy or sonography may be used as the first imaging study, and both can aid in distinguishing among the disorders to different degrees. However, sonography is becoming the preferred modality, primarily because of the superior anatomic detail provided. Scrotal masses are also best depicted with sonography, although MR imaging can occasionally be a useful adjunctive modality. In cases of suspected cryptorchidism with equivocal clinical findings, both sonography and MR imaging may be useful, although sonography is usually the initial study. Knowledge of characteristic imaging appearances, as well as benefits and limitations of the available modalities, enables appropriate, expeditious radiologic evaluation of pediatric scrotal disorders.     

The relationship of caregiver coping to family outcomes during the initial year following pediatric traumatic injury.

This study identified coping strategies associated with caregiver outcomes following pediatric injury and examined injury type as a moderator of coping efficacy. Families of 103 children with traumatic brain injury (TBI) and 71 children with orthopedic injuries were followed prospectively during the initial year postinjury. The groups had comparable preinjury characteristics and hospitalization experiences but differed on neurological insult. In hierarchical regression analyses, acceptance was associated with lower burden and denial was associated with greater distress in both groups. Active coping resulted in higher distress following TBI but not orthopedic injuries. Conversely, the use of humor was related to diminishing distress following TBI but unrelated to distress following orthopedic injuries. Results are discussed in terms of the implications for intervention following TBI. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Magnetic resonance imaging of knee injuries in children

The appearances of knee injuries on MR imaging are less well documented in children than adults. Some patterns of injury are shared by both groups of patients, e. g. meniscal damage. The frequency of specific injuries may differ, e. g. anterior cruciate ligament (ACL) tear. Congenital abnormality, coexistent pathology and previous treatment of the knee appear to be associated with meniscal problems. Discoid menisci are seen most frequently in children and have unique features on MR scans. Cruciate ligament tears are difficult to diagnose in the smallest children. The ACL may not be identified due to its small size. Normal bone marrow signal may be confused with marrow infiltration or bone microfracture. Radiographically occult fractures around the knee appear to be strongly associated with ligamentous injury as in adult patients. Osteochondral fractures, osteochondral lesions and articular cartilage damage are revealed on MR scans, but their long-term effects are uncertain. It is possible to diagnose a range of knee injuries on MR scans in children. The biggest diagnostic challenge is in pre-school children.     

Head trauma

Progress in research includes studies concerning the pathophysiology and outcome of pediatric head injury, the pathology of the hippocampus in fatal injury, and the use of multivariate statistics to predict outcome in survivors. Recent research has confirmed and extended findings regarding the differential effects of closed head injury, depending on the age of the individual. These studies indicate that the consequences of head injury are more severe in older adults and in children younger than 2 years. Neuroimaging findings include evidence for delayed brain injury as a major cause of mortality and disability. Functional brain imaging provides evidence for cerebral dysfunction that is not appreciated by structural brain imaging techniques and may have a stronger relationship to neurobehavioral sequelae. The neurobehavioral sequelae frequently implicate frontal dysfunction, even in the absence of structural findings on computed tomography or magnetic resonance imaging. Studies of mild head injury have expanded our knowledge concerning the pathogenesis of postconcussional symptoms, including a preinjury vulnerability based on recent life events. Persistent postconcussional symptoms after mild head injury are frequently associated with emotional disturbance of clinical proportions.     

Proton MR spectroscopy after acute central nervous system injury: outcome prediction in neonates, infants, and children

PURPOSE: To evaluate the usefulness of proton magnetic resonance (MR) spectroscopy in predicting 6-12-month neurologic outcome in children after central nervous system injuries. MATERIALS AND METHODS: Localized single-voxel, 20-msec-echo-time MR spectra (including N-acetylaspartate [NAA], choline [Ch], creatine and phosphocreatine [Cr]) were obtained in the occipital gray matter in 82 patients and 24 control patients. Patient age groups were defined as neonates (< or = 1 month [n = 23]), infants (1-18 months [n = 31]), and children (> or = 18 months [n = 28]). Metabolite ratios and the presence of lactate were determined. Linear discriminant analysis-with admission clinical data, proton MR spectroscopy findings, and MR imaging score (three-point scale based on severity of structural neuroimaging changes)-was performed to help predict outcome in each patient. Findings were then compared with the actual 6-12-month outcome assigned by a pediatric neurologist. RESULTS: Outcome on the basis of proton MR spectroscopy findings combined with clinical data and MR imaging score was predicted correctly in 91% of neonates and in 100% of infants and children. Outcome on the basis of clinical data and MR imaging score alone was 83% in neonates, 84% in infants, and 93% in children. The presence of lactate was significantly higher in patients with poor outcome than in patients with good-moderate outcomes in all three age groups (neonates, 38% vs 5%; infants, 87% vs 5%; children, 64% vs 10% [chi 2 test, P < .02]). In children with poor outcomes, NAA/Cr ratios were significantly lower in infants (P = .006) and children (P < .001), and NAA/Ch ratios were significantly lower in infants (P = .001) and neonates (P = .05). CONCLUSION: Findings at proton MR spectroscopy helped predict long-term neurologic outcomes in children after central nervous system injury.     

Multivoxel proton MR spectroscopy and hemodynamic MR imaging of childhood brain tumors: preliminary observations

PURPOSE: To assess multivoxel proton MR spectroscopy combined with MR imaging and hemodynamic MR imaging in the evaluation of brain tumors in children and young adults. METHODS: Fifteen patients with brain tumors and 10 healthy children underwent MR imaging and MR spectroscopy on a 1.5-T system. Ten patients with tumors had both MR spectroscopy and hemodynamic MR imaging. MR spectroscopy data sets with 1 cm3 to 3.4 cm3 resolution were acquired within 8.5 minutes by using a point-resolved spectroscopic, chemical-shift imaging technique in two dimensions with volume preselection. MR imaging was performed using fast spin-echo techniques. Hemodynamic MR imaging data were acquired every 2.5 seconds at one anatomic level using a spoiled gradient-echo sequence during intravenous bolus administration of contrast material. RESULTS: Assessment with multivoxel MR spectroscopy and hemodynamic MR imaging added about 30 minutes to the total MR examination time. Normal tissue exhibited spectral peaks from biologically significant compounds such as N-acetylaspartate (NAA), choline-containing compounds (Cho), and total creatine (tCr). Twelve biopsy-proved tumors exhibited prominent Cho, reduced NAA, variable tCr, and/or lactate or lipids, and two showed increased hemodynamic parameters. Three of the tumors treated with radiation did not reveal prominent levels of Cho. Tissue necrosis had no Cho, NAA, or tCr, and reduced hemodynamics. CONCLUSIONS: Preliminary findings by MR spectroscopy combined with MR imaging and hemodynamic MR imaging suggest that regions of active tumor may be differentiated from areas of normal tissue and areas of necrosis. These findings may enable metabolic and hemodynamic characterization of childhood brain tumors as well as suggest their response to therapy.     

Childhood moyamoya disease: hemodynamic MRI

BACKGROUND: Childhood moyamoya disease is a rare progressive cerebrovascular disease. OBJECTIVE: To evaluate cerebral hemodynamics using dynamic Gd-DTPA-enhanced imaging in children with moyamoya disease. MATERIALS AND METHODS: Eight children (2-11 years of age) with the clinical and angiographic findings typical of moyamoya disease, before and/or after surgical intervention (pial synangiosis), underwent conventional MR imaging (MRI) and hemodynamic MR imaging (HMRI). HMRI used a spoiled gradient-echo with low flip angle (10 deg) and long TE (TR/TE = 24/15 ms) to minimize T 1 effects and emphasize T 2* weighting. Raw and calculated hemodynamic images were reviewed. Three-dimensional time-of-flight MR angiography (MRA) and perfusion brain single photon emission computed tomography (SPECT) were also performed. RESULTS: Abnormal hemodynamic maps resulting from vascular stenosis or occlusion and basal collaterals were observed in six patient studies. HMRI depicted perfusion dynamics of affected cerebrovascular territories, detected cortical perfusion deficits, and complemented conventional MRI and MRA. HMRI findings were consistent with those of catheter angiography and perfusion SPECT. CONCLUSION: Our preliminary experience suggests that HMRI may be of value in the preoperative and postoperative evaluation of surgical interventions in moyamoya disease.     

Global phylogeography of the ridley sea turtles (Lepidochelys spp.) as inferred from mitochondrial DNA sequences

BACKGROUND: The cardiovascular applications of magnetic resonance (MR) techniques in coronary artery disease have increased considerably in recent years. Technical advantages of MR imaging are the excellent spatial resolution, the characterization of myocardial tissue, and the potential for three-dimensional imaging. These characteristics allow the accurate assessment of left ventricular mass and volume, the differentiation of infarcted from normal tissue, and the determination of systolic wall thickening and regional wall motion abnormalities. METHODS: In addition to the conventionally used spin-echo and cine-echo techniques, newer techniques such as myocardial tagging, ultrafast MR imaging and MR coronary angiography have been developed. These newer techniques allow a more accurate assessment of ventricular function (tagging), myocardial perfusion (ultrafast imaging), and evaluation of stenosis severity (MR coronary angiography). Particularly early detection and flow assessment of stenosed coronary arteries and bypasses by MR angiography would constitute a major breakthrough in cardiovascular MR imaging. Apart from the MR imaging techniques, cardiac metabolism may be well assessed using MR spectroscopy. This provides unique information on the metabolic behaviour of the myocardium under conditions stress-induced ischemia. However, the definite niche of cardiac MR spectroscopy has still to be settled. CONCLUSION: Currently, MR techniques allow the evaluation of anatomy and function (accepted use), perfusion and viability (development phase), and coronary angiography (experimental phase). A particular strength of MR imaging is that one single MR test may encompass cardiac anatomy, perfusion, function, metabolism and coronary angiography. The replacement of multiple diagnostic tests with one MR test may have major effects on cardiovascular healthcare economics and would outweight the cost inherent to the MR angiography procedure.     

Magnetic resonance images of neuronal migration anomalies

Neuronal migration anomalies are a spectrum of brain malformations caused by insults to migrating neuroblasts during the sixth week to fifth month of gestation. To study the characteristics of MRI findings in migration anomalies, MR images of 36 patients (28 children and 8 adults) with migration anomalies were evaluated. Five patients had lissencephaly, eight had pachygyria, twelve had schizencephaly, six had heterotopias of gray matter, three had hemimegalencephaly, and two had polymicrogyria. The frequency of migration anomalies was 0.51% of all cranial MRI studies and 1.21% of pediatric cranial MRI studies at our hospital. The major clinical presentations of these patients were seizure (64%), development delay (42%), motor deficits (42%) and mental retardation (25%). Twenty-five patients (69%) associated with other brain anomalies, including: other migration anomalies in 12 cases (33%), absence of the septum pellucidum in 10 cases (28%), Dandy-Walker malformation/variant in 5 cases, arachnoid cyst in 4 cases, agenesis of the corpus callosum in 3 cases, holoprosencephaly in 2 cases, mega cisterna magna in 1 case and cephalocele in 1 case. Some of them presented with multiple complicated anomalies. As MR imaging provides superb gray-white matter distinction, details of cortical anatomy and multiplanar capability, it can clearly delineate the detail morphologic changes of the brain caused by neuronal migration disorders as well as the associated anomalies.     

MR imaging of pediatric musculoskeletal inflammatory and infectious disorders

Inflammatory and infectious disorders of the skeletally immature extraspinal musculoskeletal system affect the bones, contiguous soft tissues, muscles, and joints. MR imaging of osteomyelitis, soft tissue infection, inflammatory muscle disease, and acute and chronic joint disease are discussed in the context of underlying pathophysiology. Discussion includes imaging optimization, contribution of MR imaging to overall patient management, and differential diagnostic considerations for the pediatric patient.     

Magnetic resonance imaging of acute stroke

In the investigation of ischemic stroke, conventional structural magnetic resonance (MR) techniques (e.g., T1-weighted imaging, T2-weighted imaging, and proton density-weighted imaging) are valuable for the assessment of infarct extent and location beyond the first 12 to 24 hours after onset, and can be combined with MR angiography to noninvasively assess the intracranial and extracranial vasculature. However, during the critical first 6 to 12 hours, the probable period of greatest therapeutic opportunity, these methods do not adequately assess the extent and severity of ischemia. Recent developments in functional MR imaging are showing great promise for the detection of developing focal cerebral ischemic lesions within the first hours. These include (1) diffusion-weighted imaging, which provides physiologic information about the self-diffusion of water, thereby detecting one of the first elements in the pathophysiologic cascade leading to ischemic injury; and (2) perfusion imaging. The detection of acute intraparenchymal hemorrhagic stroke by susceptibility weighted MR has also been reported. In combination with MR angiography, these methods may allow the detection of the site, extent, mechanism, and tissue viability of acute stroke lesions in one imaging study. Imaging of cerebral metabolites with MR spectroscopy along with diffusion-weighted imaging and perfusion imaging may also provide new insights into ischemic stroke pathophysiology. In light of these advances in structural and functional MR, their potential uses in the study of the cerebral ischemic pathophysiology and in clinical practice are described, along with their advantages and limitations.     

Congenital ocular motor apraxia: imaging findings

PURPOSE: To determine the frequency of cerebellar and cerebral abnormalities on brain imaging studies in children with congenital ocular motor apraxia. METHODS: Brain imaging studies were performed in 19 children with typical congenital ocular motor apraxia who were in the care of a visual impairment program at a children's hospital. Independent clinical review categorized the subjects as having partial (n = 10) or expanded (n = 9) congenital ocular motor apraxia on the basis of extent of associated speech or neurodevelopmental problems. Fifteen CT studies and 13 MR examinations of the brain performed in these children were reviewed independently by two pediatric neuroradiologists. Radiologic findings were agreed on by consensus. RESULTS: Cerebellar abnormalities were found in 12 of 19 cases. The cerebellar vermis was small in 10 children. A small cerebellar vermis was the only abnormality in five of 10 children with partial congenital ocular motor apraxia and in two of nine children with expanded congenital ocular motor apraxia. Among seven children with a small vermis examined with high-resolution MR imaging, the inferior portion of the vermis was preferentially involved in each case. Of these seven subjects, none of four with partial congenital ocular motor apraxia but two of three with expanded congenital ocular motor apraxia had an abnormality of the superior portion of the vermis. Miscellaneous supratentorial lesions affecting both gray and white matter were found in six subjects. Five of the 19 children had normal imaging findings. CONCLUSION: Inferior vermian hypoplasia is the most common abnormality in children with congenital ocular motor apraxia.     

Clinical, neurodiagnostic, and MR findings in children with spinal and brain stem multiple sclerosis

PURPOSE: To describe the clinical, neurodiagnostic, and MR findings in seven children with brain stem and spinal multiple sclerosis. METHODS: Spinal or brain stem multiple sclerosis was diagnosed in seven children between 1986 and 1992. All patients had neurologic and MR examinations as well as neurodiagnostic testing, including spinal fluid analysis and brain stem and auditory evoked potentials. RESULTS: Three children had clinical findings and masslike lesions in the brain stem (two) or spinal cord (one) suggestive of neoplasm, which prompted biopsy (two) or radiation therapy (one). Five of six patients with spinal involvement had cord swelling with increased signal on T2-weighted images over at least three cord segments, and two children had essentially holocord involvement. Three children had normal cranial MR at presentation. CONCLUSIONS: Multiple sclerosis involvement of the brain stem and spinal cord may be associated with extensive swelling and MR signal changes suggestive of neoplasm without typical cerebral white matter abnormalities. Serial clinical and neuroimaging examinations may be necessary to make a definitive diagnosis of multiple sclerosis in children.     

Metabolic activation of 2,6-dichlorobenzonitrile, an olfactory-specific toxicant, by rat, rabbit, and human cytochromes P450

The authors posit that cellular edema is the major contributor to brain swelling in diffuse head injury and that the contribution of vasogenic edema may be overemphasized. The objective of this study was to determine the early time course of blood-brain barrier (BBB) changes in diffuse closed head injury and to what extent barrier permeability is affected by the secondary insults of hypoxia and hypotension. The BBB disruption was quantified and visualized using T1-weighted magnetic resonance (MR) imaging following intravenous administration of the MR contrast agent gadolinium-diethylenetriamine pentaacetic acid. To avoid the effect of blood volume changes, the maximum signal intensity (SI) enhancement was used to calculate the difference in BBB disruption. A new impact-acceleration model was used to induce closed head injury. Forty-five adult Sprague-Dawley rats were separated into four groups: Group I, sham operated (four animals), Group II, hypoxia and hypotension (four animals), Group III, trauma only (23 animals), and Group IV, trauma coupled with hypoxia and hypotension (14 animals). After trauma was induced, a 30-minute insult of hypoxia (PaO2 40 mm Hg) and hypotension (mean arterial blood pressure 30 mm Hg) was imposed, after which the animals were resuscitated. In the trauma-induced animals, the SI increased dramatically immediately after impact. By 15 minutes permeability decreased exponentially and by 30 minutes it was equal to that of control animals. When trauma was coupled with secondary insult, the SI enhancement was lower after the trauma, consistent with reduced blood pressure and blood flow. However, the SI increased dramatically on reperfusion and was equal to that of control by 60 minutes after the combined insult. In conclusion, the authors suggest that closed head injury is associated with a rapid and transient BBB opening that begins at the time of the trauma and lasts no more than 30 minutes. It has also been shown that addition of posttraumatic secondary insult-hypoxia and hypotension-prolongs the time of BBB breakdown after closed head injury. The authors further conclude that MR imaging is an excellent technique to follow (time resolution 1-1.5 minutes) the evolution of trauma-induced BBB damage noninvasively from as early as a few minutes up to hours or even longer after the trauma occurs.     

Molecular mechanism for the relative binding affinity to the intestinal peptide carrier. Comparison of three ACE-inhibitors: enalapril, enalaprilat, and lisinopril

Three-dimensional magnetic resonance angiography (MRA) is a noninvasive technique that images the intracranial arterial vasculature without contrast agents. The suitability of MRA was evaluated for routine use and all children were prospectively studied with conventional MR imaging and time off flight MRA (FISP3D). All MR studies were performed on a 1.5 T-MRA system using a circularly polarized head coil. The study comprised 140 children, ages 3 weeks to 18 years, with different neuropediatric diseases. Major cervical and intracranial arteries were visualized in all age groups. Smaller branches of the supratentorial arteries were identified inconstantly and the number of arteries visualized increased up to the age of 6 years. Sixty-seven children (47%) had normal intracranial vasculature. MRA demonstrated anatomic variations in 21 patients (15%). Twenty-two of 32 children with congenital malformations demonstrated abnormalities of the intracranial vasculature. The diagnostic value of MRA was confirmed in 11 of 12 patients after neonatal stroke and in 3 of 10 children after stroke at older ages. Seven of 18 children with acute hemorrhage demonstrated arteriovenous malformations or an aneurysm on MRA. The correlation with digital subtraction angiographic findings was established in 13 patients. In 9 of 13 children with brain tumor, MRA proved to be diagnostically valuable. MRA proved to be of particular value in the evaluation of the carotid artery following extracorporeal membrane oxygenation therapy. MRA can be used in children of all age groups.(ABSTRACT TRUNCATED AT 250 WORDS)     

Diffusion-weighted MR imaging of acute cerebral ischemia

Diffusion-weighted MR imaging has been used in studies on experimental animal models and on patients with acute cerebral ischemia. Compared with CT and conventional MR techniques, diffusion-weighted imaging can provide earlier and more precise detection of the location and the extent of an ischemic lesion during the critical first few hours after the onset of stroke. Quantitative apparent diffusion coefficient (ADC) mapping of the brain water can also be carried out by recording a series of diffusion-weighted images with different amplitudes of the displacement encoding gradients. ADC maps can provide important information about the extra- and intracellular water homeostasis. ADC reduction of the tissue water is one of the early signals of the pathophysiological cascade resulting from ischemic tissue injury. Diffusion MR imaging has become a valuable tool in stroke research. It may also prove a valuable tool in monitoring the efficiency of therapeutic effects in stroke patients. It is our intention to provide an overview of the recent development in this area with emphasis on the diffusion-weighted MR techniques, and to discuss the possible underlying biophysical mechanisms responsible for the contrast of diffusion-weighted imaging.     

Phenytoin-induced dystonia and choreoathetosis in two retarded epileptic children

Similar movement disorders developed in two 8-year-old retarded children while they were receiving phenytoin. Seizures subsequent to a diphtheria-pertussis-tetanus immunization had developed in each child at 1 to 2 months of age. A static encephalopathy ensued, characterized by mental retardation, ataxia, spasticity, and a mixed seizure disorder. Intermittent dystonia and choreoathetosis developed insidiously while serum phenytoin concentrations were in the therapeutic range. Sustained dystonia and choreoatheosis developed 2 hours after an oral provocation with phenytoin. The baseline abnormalities on the electroencephalogram remained unchanged during the choreoathetosis. Recognizable metabolic abnormalities known to be associated with similar movement disorders were excluded. It was concluded from these studies that the movement disorder is secondary to phenytoin and can occur at therapeutic serum concentrations. Phenytoin is a central anticholinergic agent and a central stimulant of serotonin, and may induce movement disorders as a result of altering these neurotransmitters in the brain. The variable expression of these movement disorders may relate to the nature of the preexisting striatal insult.     

A prospective study of short- and long-term outcomes after traumatic brain injury in children: Behavior and achievement.

Longitudinal behavior and achievement outcomes of traumatic brain injury (TBI) were investigated in 53 children with severe TBI, 56 children with moderate TBI, and 80 children with orthopedic injuries not involving brain insult. Measures of preinjury child and family status and of postinjury achievement skills were administered shortly after injury. Assessments were repeated 3 times across a mean follow-up interval of 4 years. Results from mixed model analysis revealed persisting sequelae of TBI. Recovery of math skills was observed in the severe TBI group but only for children from less stressed families. Social disadvantage in children with TBI predicted more adverse behavioral sequelae and less favorable changes in some outcome measures. The findings suggest that pediatric TBI has long-term effects on behavior and achievement but that postinjury progress is influenced by the family environment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ocular adnexal oncocytoma: a case series and clinicopathologic review of the literature

OBJECTIVE: Headache is a common complaint in children and brain imaging has become widely used to evaluate this clinical condition. We studied the value of neuroimaging in children with chronic headaches. PATIENTS AND METHODS: A retrospective chart review was conducted of all children referred to the pediatric outpatient clinic for evaluation of headache over a 3-year period. The charts were reviewed for headache characteristics, clinical indications for performing neuroimaging, and imaging results. Special attention was paid to evidence of space-occupying lesions. RESULTS: A total of 160 records were studied, with subjects ranging in age from 4 to 14 years. Most patients were diagnosed as having migraine headaches (60%) or chronic tension headaches (29.5%). Other diagnoses were post-traumatic (6%) and unclassified (4%). Sixty-six patients (41%) had computed tomography imaging performed. In most cases, brain imaging studies were performed because of clinical data (41%) like atypical pattern, sleep-related headache or increase of headache, because of the parents' concerns about brain lesions (38%) and because of an age less than 5 years (14%). Structural changes were found on brain imaging in 4 patients, but none indicated the presence of a treatable space-occupying lesion and all were deemed unrelated to the headache. Our findings of no relevant abnormalities in a series of 66 neuroimaging studies indicate that the maximal rate at which such abnormalities might appear in this population is 4.4%. CONCLUSIONS: These results indicate that neuroimaging studies have very limited value in the clinical evaluation of pediatric patients with chronic headache and should be reserved for those patients with clinical evidence suggestive of underlying structural lesion.