Controlled trial of transfusions for silent cerebral infarcts in sickle cell anemia.

BACKGROUND: Silent cerebral infarcts are the most common neurologic injury in children with sickle cell anemia and are associated with the recurrence of an infarct (stroke or silent cerebral infarct). We tested the hypothesis that the incidence of the recurrence of an infarct would be lower among children who underwent regular blood-transfusion therapy than among those who received standard care. METHODS: In this randomized, single-blind clinical trial, we randomly assigned children with sickle cell anemia to receive regular blood transfusions (transfusion group) or standard care (observation group). Participants were between 5 and 15 years of age, with no history of stroke and with one or more silent cerebral infarcts on magnetic resonance imaging and a neurologic examination showing no abnormalities corresponding to these lesions. The primary end point was the recurrence of an infarct, defined as a stroke or a new or enlarged silent cerebral infarct. RESULTS: A total of 196 children (mean age, 10 years) were randomly assigned to the observation or transfusion group and were followed for a median of 3 years. In the transfusion group, 6 of 99 children (6%) had an end-point event (1 had a stroke, and 5 had new or enlarged silent cerebral infarcts). In the observation group, 14 of 97 children (14%) had an end-point event (7 had strokes, and 7 had new or enlarged silent cerebral infarcts). The incidence of the primary end point in the transfusion and observation groups was 2.0 and 4.8 events, respectively, per 100 years at risk, corresponding to an incidence rate ratio of 0.41 (95% confidence interval, 0.12 to 0.99; P=0.04). CONCLUSIONS: Regular blood-transfusion therapy significantly reduced the incidence of the recurrence of cerebral infarct in children with sickle cell anemia. (Funded by the National Institute of Neurological Disorders and Stroke and others; Silent Cerebral Infarct Multi-Center Clinical Trial ClinicalTrials.gov number, NCT00072761, and Current Controlled Trials number, ISRCTN52713285.).

Reproducibility of detecting silent cerebral infarcts in pediatric sickle cell anemia.

Detecting silent cerebral infarcts on magnetic resonance images (MRIs) in children with sickle cell anemia is challenging, yet reproducibility of readings has not been examined in this population. We evaluated consensus rating, inter-, and intra-grader agreement associated with detecting silent cerebral infarct on screening MRI in the Silent Infarct Transfusion Trial. Three neuroradiologists provided consensus decisions for 1073 MRIs. A random sample of 53 scans was reanalyzed in blinded fashion. Agreement between first and second consensus ratings was substantial (κ = 0.70, P < .0001), as was overall intergrader agreement (κ = 0.76, P < .0001). In the test-retest sample, intragrader agreement ranged from κ of 0.57 to 0.76. Consensus decisions were more concordant when MRIs contained more than one larger lesions. Routine use of MRI to screen for silent cerebral infarcts in the research setting is reproducible in sickle cell anemia and agreement among neuroradiologists is sufficient.

Acute silent cerebral ischemic events in children with sickle cell anemia.

BACKGROUND: Irregular, sporadic episodes of ischemic brain injury are known to occur in sickle cell anemia (SCA), resulting in overt stroke and silent cerebral infarction. Ongoing ischemia in other organs is common in SCA but has never been documented in the brain. OBJECTIVE: To test the hypothesis that acute silent cerebral ischemic events (ASCIEs) are frequent and potentially transient. DESIGN: Cross-sectional and cohort study of children with SCA screened by magnetic resonance imaging (MRI) of the brain for a randomized clinical trial. SETTING: Clinical trial setting in tertiary care centers. PATIENTS: Asymptomatic children with SCA without known stroke, neurologic injury, or epilepsy not receiving treatment with transfusions or hydroxyurea. MAIN OUTCOME MEASURE: Incidence of ASCIEs calculated using single diffusion-weighted MRI scans (acute ischemic events that occurred within 10 days of the MRI). RESULTS: Acute silent cerebral ischemic events were detected on 1.3% of MRIs (10 of 771) in 652 children (mean age, 10.0 years), with an incidence of 47.3 events per 100 patient-years (95% CI, 22.7-87.2). Two of 10 children with ASCIEs had follow-up MRIs of the brain; only 1 had silent cerebral infarction in the same location as the previously detected ASCIE. CONCLUSIONS: Children with SCA experience ongoing (chronic, intermittent) cerebral ischemia, sometimes reversible, far more frequently than previously recognized. The brain in SCA is at constant threat of ischemia.

Incidental findings on brain magnetic resonance imaging of children with sickle cell disease.

OBJECTIVE: We describe the prevalence and range of incidental intracranial abnormalities identified through MRI of the brain in a large group of children screened for a clinical trial. METHODS: We included 953 children between 5 and 14 years of age who were screened with MRI of the brain for the Silent Infarct Transfusion Trial. All had sickle cell anemia or sickle beta-null thalassemia. MRI scans were interpreted by 3 neuroradiologists. MRI scans reported to have any abnormality were reviewed by 2 study neuroradiologists. Incidental findings were classified into 4 categories, that is, no, routine, urgent, or immediate referral recommended. Cerebral infarctions and vascular lesions were not considered incidental and were excluded. RESULTS: We identified 63 children (6.6% [95% confidence interval: 5.1%-8.4%]) with 68 incidental intracranial MRI findings. Findings were classified as urgent in 6 cases (0.6%), routine in 25 cases (2.6%), and no referral required in 32 cases (3.4%). No children required immediate referral. Two children with urgent findings underwent surgery in the subsequent 6 months. CONCLUSION: In this large cohort of children, incidental intracranial findings were identified for 6.6%, with potentially serious or urgent findings for 0.6%.

Silent Cerebral Infarct Transfusion (SIT) trial imaging core: application of novel imaging information technology for rapid and central review of MRI of the brain.

The Silent Cerebral Infarct Multicenter Transfusion (SIT) Trial is a multi-institutional intervention trial in which children with silent cerebral infarcts are randomized to receive either blood transfusion therapy or observation (standard care) for 36 months. The SIT Trial is scheduled to enroll approximately 1,880 children with sickle cell disease from 29 clinical sites in the United States, Canada, UK, and France. Each child undergoes a screening magnetic resonance imaging (MRI) of the brain to detect the presence of silent cerebral infarct-like lesions, a pre-randomization (baseline) MRI and exit MRI to determine if there are new or enlarged cerebral infarcts, using a designated, prospective imaging protocol. The objective of this manuscript is to describe the innovative method used to process and adjudicate imaging studies for an international trial with a primary endpoint that includes neuroimaging. Institution investigators at each site were provided with computer hardware and software for transmission of MRI images that allow them to strip the scans of all personal information and add unique study identifiers. Three neuroradiologists at separate academic centers review MRI studies and determine the presence or absence of silent cerebral infarct-like lesions. Their findings are subsequently placed on web-based case report forms and sent to the Statistical Coordinating Center. The average time from imaging center receipt of the MRI study to the radiology committee report back to the local site is less than two working days. This novel strategy was designed to maximize efficiency and minimize cost of a complex large multicenter trial that depends heavily on neuroimaging for entry criteria and assessment for the primary outcome measures. The technology, process, and expertise used in the SIT Trial can be adapted to virtually any clinical research trial with digital imaging requirements.

Elevated lactate as an early marker of brain injury in inflicted traumatic brain injury.

BACKGROUND: Traumatic brain injury is a major cause of disability and death in the pediatric population. The metabolic and neurochemical abnormalities that underlie traumatic brain injury remain poorly understood, but hypoxia-ischemic injury might play an important role. OBJECTIVE: This study evaluated children with inflicted traumatic brain injury using magnetic resonance spectroscopy (MRS). We postulated that children with hypoxic-ischemic injury indicated by elevated lactate in the acute phase of injury will have worse early neurological status and short-term clinical outcomes than those without lactate upon MRS. MATERIALS AND METHODS: This prospective study employed proton MRS to sample bilaterally the frontal lobes and the parasagittal cortex within the parietal and occipital lobes of 11 patients with inflicted traumatic brain injury who were undergoing a clinical MRI examination. Patients' measured clinical course while hospitalized included initial neurological evaluation, presence of seizure activity, need for admission to the pediatric intensive care unit (PICU), number of days hospitalized, presence of retinal hemorrhages and presence of bone fractures. Measurement of outcome was determined using the Pediatric Overall Performance Category Scale (POPCS; 1=good performance; 6=death). RESULTS: Four children demonstrated elevated lactate and diminished N-acetyl aspartate (a neuronal marker) within several regions, indicating global ischemic injury (lactate-positive global group). These four children all had seizure activity and abnormal initial neurological examinations and required admission to the PICU. The mean POPCS for this group was 3.25. In four other children, lactate was detected within at least one region, indicating a focal ischemic injury (lactate-positive focal group); two of these children had seizure activity, and two had an abnormal initial neurological examination. The mean POPCS score was 1.5 for this group. The remaining three children had no evidence of lactate upon MRS (lactate-negative group). These children did not have seizure activity, did not require admission to the PICU, nor did they have initial abnormal neurological examinations. The mean POPCS score was 1.3 for this group. SUMMARY: Patients with inflicted traumatic brain injury and evidence of hypoxic-ischemic injury as indicated by elevated lactate on MRS tend to have worse early neurological status and early outcome scores. Lactate levels as sampled by MRS might predict early clinical outcome in inflicted traumatic brain injury.

The clinical syndrome of creatine transporter deficiency.

To describe the clinical, spectroscopic and neuropsychological features of the first family diagnosed with a defect in the creatine transporter. Proton Magnetic Resonance Spectroscopy (MRS) indicated an absence of creatine and phosphocreatine in the brain of a male patient characterized by developmental delay, mild epilepsy and severe expressive language impairment. Subsequent genetic testing revealed a defect in the X-linked creatine transporter (SLC6A8/CT1), with a hemizygous mutation in the patient and a heterozygous mutation for the female carriers. Magnetic resonance imaging and spectroscopy examinations were performed on a 1.5T clinical MR Scanner. Neuropsychological examinations were performed on the index patient and maternal relatives. Preliminary spectroscopy results indicate the disorder prevents transport of creatine and phosphocreatine in the brain of the affected male. However, the skeletal muscle demonstrates the presence of creatine and phosphocreatine which correlates clinically with normal structure and function. Female carriers demonstrated impairments in confrontational naming and verbal memory assessments. This new neurological syndrome is associated with developmental delay, mild epilepsy, severe language impairment. MR Spectroscopy is a non-invasive method for obtaining a preliminary diagnosis of this disorder. Muscle creatine uptake may be normal in this disorder.

Language processing during natural sleep in a 6-year-old boy, as assessed with functional MR imaging.

Functional MR imaging for language lateralization was performed in a 6-year-old child before neurosurgical intervention. A passive story-listening task was used; this revealed a bilateral language network. The task was repeated during the same session when the child had fallen asleep and surprisingly yielded strong activation in similar language areas. Our findings suggest that language processing does occur during natural sleep, even in young children. This potentially allows for an assessment of language functions, even in sleeping children.

Vein of Galen aneurysmal malformation: diagnosis and treatment of 13 children with extended clinical follow-up.

BACKGROUND AND PURPOSE: We herein present our experience in diagnosing and treating 13 children with vein of Galen aneurysmal malformations (VGAM), with an emphasis on possible prognostic indicators, endovascular strategies, factors affecting treatment during the neonatal period, and long-term follow-up. With this review, we hope to identify those factors that have the most significant prognostic value in determining long-term outcomes in children with VGAM. METHODS: We retrospectively reviewed the radiology studies, hospital charts, and outpatient clinic chart notes (when applicable) of 13 children evaluated and treated for VGAM at a single tertiary care pediatric hospital. Clinical presentation, diagnostic methods, treatment strategies, and outcome were documented for each child. The present neurologic status and level of function of each patient was determined by review of the outpatient charts and direct contact with the clinicians who were conducting the follow-up. Outcome was graded on a 5-point scale, ranging from 0 (death) to 4 (normal), taking into account only neurologic and developmental characteristics. RESULTS: Eight of 13 patients presented as neonates with congestive heart failure. The other five patients ranged in age from 4 months to 13 years at the time of presentation. The five patients presenting outside of the neonatal period achieved normal or near-normal outcomes. Two of the eight patients presenting during the neonatal period achieved normal or near-normal outcomes, one experienced significant impairment, and the other five died. We were unable to identify significant differences in outcome on the basis of differences in treatment strategies. CONCLUSION: Our experience confirms that children with VGAM presenting during the neonatal period have a generally much worse prognosis than do those presenting later in childhood. Complicating factors in the management and treatment of these children are discussed in light of their impact on outcome.