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Dawn E Saunders

Publications and source records attributed to Dawn E Saunders.

13 recordsLinked to original sources
PubMed2006

Is there a role for magnetic resonance imaging in the evaluation of non-traumatic intraparenchymal haemorrhage in children?

BACKGROUND: In contrast to adults, intraparenchymal haemorrhage (IPH) is at least as common as ischaemic stroke in children. There is often uncertainty about the most appropriate modality for imaging in the acute stage. OBJECTIVE: To examine the diagnostic value of MRI and MR angiography (MRA) in the detection of underlying pathology in children with non-traumatic IPH. MATERIALS AND METHODS: A retrospective review was conducted of children with IPH from January 1997 to March 2003. After exclusion of patients with traumatic IPH or previously diagnosed vascular malformation, aneurysm, or brain tumour, 50 children were identified. Case notes and imaging studies were reviewed. RESULTS: An underlying lesion was demonstrated with MR in two-thirds of children (25/38) with IPH. A vascular lesion was the commonest cause, followed by tumour. Three children had false-negative MR scans. CONCLUSION: MR is a valuable non-invasive imaging modality for detection of both vascular and non-vascular causes of paediatric IPH. The high rate of the latter in childhood makes incorporation of MR into paediatric IPH imaging protocols especially important. Clinical guidelines regarding the optimum sequence of investigations in non-traumatic IPH would be helpful to standardize practice and enable critical appraisal.

Adolescent↗
PubMed2006

Impact of frontal white matter lesions on performance monitoring: ERP evidence for cortical disconnection.

We examined the impact of discrete white matter lesions in the frontal lobes on event-related potential (ERP) correlates of performance monitoring. We tested the hypothesis that abnormal performance monitoring may result from injury to white matter without evidence of injury to grey matter in the frontal lobes. It was predicted that such lesions may result in disconnection of the lateral and medial frontal cortices. The close interaction of these two areas has been implicated in performance monitoring. Two fast-choice response tasks were administered to patients with MRI-confirmed frontal white matter lesions due to sickle cell disease (SCD) vasculopathy (n = 11; age = 11-23 years; 6 unilateral left lesions and 5 bilateral lesions) and two control groups: SCD patients without brain lesions and non-sickle cell sibling controls (n = 11 each). Stimulus-locked ERP components N2 and P3 were not significantly affected by presence of lesions. The difference between response-locked components to correct trials (correct-response negativity--CRN) and erroneous trials (error-related negativity--ERN) was diminished in patients with unilateral and bilateral frontal white matter lesions. This finding was due to a significantly attenuated ERN amplitude in lesion patients compared with both sibling and non-lesion control groups. These ERP findings were not due to performance differences between groups and hence reflect a compromised neural substrate underlying performance monitoring. The latter may also contribute to the deficits in executive function tasks observed in these patients. As disruption to ERP markers of error processing was found in the absence of lesions to the lateral or medial frontal cortex, we conclude that a functional connection between these areas facilitates performance monitoring, possibly implemented via tracts traversing the deep frontal white matter.

Adolescent↗
PubMed2006

Pantothenate kinase 2 mutation with classic pantothenate-kinase-associated neurodegeneration without 'eye-of-the-tiger' sign on MRI in a pair of siblings.

It has been postulated that all patients with pantothenate kinase 2 (PANK2) mutations causing pantothenate-kinase-associated neurodegeneration (PKAN) are associated with the 'eye-of-the-tiger' sign on MRI. We report a pair of siblings who presented with dystonia and who have been found to be homozygous for 104C>A, S35X mutation, confirming the diagnosis of PKAN. They do not have the typical iron deposition in the globi pallida or substantia nigra on MR imaging.

Child, Preschool↗
PubMed2006

Detecting white matter injury in sickle cell disease using voxel-based morphometry.

OBJECTIVE: Sickle cell disease (SCD) is associated with cerebrovascular disease, cerebral infarction, and cognitive dysfunction. This study aimed to detect the presence and extent of white matter abnormalities in individuals with SCD using voxel-based morphometry (VBM). METHODS: Thirty-six children and adolescents with SCD (age range, 9-24 years) and 31 controls (8-25 years) underwent magnetic resonance investigations using T1- and T2-weighted protocols. White and gray matter density maps were obtained from three-dimensional magnetic resonance imaging (MRI) data sets. Using VBM, we compared the maps between controls and SCD individuals with silent white matter infarct lesions (SCD+L; n = 16), and those without visible abnormality (SCD-L; n = 20). RESULTS: In comparison with controls, intelligence quotients (IQs) were lower in both SCD groups irrespective of presence of visible lesions. VBM showed widespread bilateral white matter abnormalities in the SCD+L group, extending beyond the regions of focal infarction in the deep anterior and posterior white matter borderzones. Bilateral white matter abnormalities were also observed in the SCD-L group, in locations similar to those in the SCD+L group. INTERPRETATION: VBM is sensitive to detection of widespread white matter injury in SCD patients in borderzones between arterial territories even in the absence of evidence of infarction. Those changes may contribute to cognitive deficits in this population.

Adolescent↗
PubMed2006

Evolution of cerebral arteriopathies in childhood arterial ischemic stroke.

OBJECTIVE: To investigate evolution of cerebral arteriopathy in children with arterial ischemic stroke (AIS) and its influence on recurrence. METHODS: Arteriopathy severity was graded on serial magnetic resonance angiograms from 50 children with first AIS; diagnostic categories were assigned. RESULTS: Arteriopathy affected 72 arteries in 43 of 50 children. Five had clinical recurrence, with reinfarction in four; another had clinically silent reinfarction. Twelve children (24%; 4 with recurrence) had progressive arteriopathy. Arteriopathy improved in 24 patients (including 1 with recurrent transient ischemic attacks) and was stable in 7 patients. Magnetic resonance angiograms remained normal in seven patients; one had recurrent stroke. Diagnoses were transient cerebral arteriopathy (n = 24), chronic cerebral arteriopathy (n = 11), arterial dissection (n = 3), possible moyamoya (n = 2), primary moyamoya (n = 1), dysplastic arteriopathy (n = 1), and cerebral vasculitis (n = 1). Some of the first two categories could represent thromboembolic arterial occlusion with recanalization. The hazard of recurrence was three times higher when arterial disease had progressed (Cox regression hazard ratio, 3.2; 95% confidence intervals, 0.5-20.3; p = 0.22). After adjustment for age and number of AIS risk factors, the hazard ratio was 3.1 (95% confidence interval, 0.4-22.2; p = 0.27). INTERPRETATION: Arteriopathy frequently progresses after childhood AIS. Further studies are needed to examine the relationship between progressive arteriopathy and recurrence.

Adolescent↗
PubMed2006

Post-varicella intracranial haemorrhage in a child.

We report a case of a 7-month-old male with primary intracranial haemorrhage 2 months after infection with varicella zoster virus (VZV). His initial clinical course was complicated by seizures and right hemiparesis; when last seen at 22 months the only positive finding was of left hand preference. Although the literature has recently established the association of arterial ischaemic stroke and VZV infection, primary intracranial haemorrhage has been reported only in one case. The child reported here had anterior interhemispheric haemorrhage due to a focal arteritis of the left anterior cerebral artery. The vascular abnormality was transient and had radiological features compatible with either a focal arteritis or vasospasm as a direct result of blood surrounding the vessels. We postulate that direct invasion of VZV caused extensive inflammation of the vessel wall and aggressive tissue penetration resulting in necrotizing angiitis and intracranial haemorrhage. We suggest that VZV infection should be considered a potential risk factor for intracranial haemorrhage in children.

Anterior Cerebral Artery↗
PubMed2005

Spontaneous regression of residual low-grade cerebellar pilocytic astrocytomas in children.

BACKGROUND: Cerebellar low-grade astrocytomas (CLGAs) of childhood are benign tumours and are usually curable by surgical resection alone or combined with adjuvant radiotherapy. OBJECTIVE: To undertake a retrospective study of our children with CLGA to determine the optimum schedule for surveillance imaging following initial surgery. In this report we describe the phenomenon of spontaneous regression of residual tumour and discuss its prognostic significance regarding future imaging. MATERIALS AND METHODS: A retrospective review was conducted of children treated for histologically proven CLGA at Great Ormond Street Hospital from 1988 to 1998. RESULTS: Of 83 children with CLGA identified, 13 (15.7%) had incomplete resections. Two children with large residual tumours associated with persistent symptoms underwent additional treatment. Eleven children were followed by surveillance imaging alone for a mean of 6.83 years (range 2-13.25 years). Spontaneous tumour regression was seen in 5 (45.5%) of the 11 children. There were no differences in age, gender, symptomatology, histological grade or Ki-67 fractions between those with spontaneous tumour regression and those with progression. There was a non-significant trend that larger volume residual tumours progressed. CONCLUSIONS: Residual tumour followed by surveillance imaging may either regress or progress. For children with residual disease we recommend surveillance imaging every 6 months for the first 2 years, every year for years 3, 4 and 5, then every second year if residual tumour is still present 5 years after initial surgery. This would detect not only progressive or recurrent disease, but also spontaneous regression which can occur later than disease progression.

Adolescent↗
PubMed2005

Complication rates of diagnostic cerebral arteriography in children.

BACKGROUND: Cerebral arteriography (CA) remains the gold standard in delineating both intra- and extracranial vascular anatomy. Most data relating to the safety of CA are drawn from studies of adult patients in whom the practicalities of the procedure, range of potential pathologies and comorbid factors are different from those in children. OBJECTIVE: To evaluate the current local and neurological complication rates of paediatric CA in the setting of a tertiary level children's hospital in the UK. MATERIALS AND METHODS: Data from patients who had undergone CA between January 1998 and July 2003 were reviewed. The medical, anaesthetic and nursing records, and angiography reports were reviewed for all identified patients. The following parameters were extracted and entered into a proforma: gender, age, ethnicity, diagnosis, cerebrovascular diagnosis, referral source, date of CA, number of vessels catheterized and local and neurological complications. RESULTS: A total of 176 CA studies were undertaken in 150 patients (median age 7.3 years, range neonate to 19 years; 83 males, 67 females) during the 5.5-year study period. The majority of referrals originated from the neurology (58%) and neurosurgery services (27.8%). No neurological complications or deaths occurred. Local complications occurred in eight children (4.5%). Five children had a groin haematoma and two had bleeding at the puncture site. A single child had a reduced pedal pulse distal to the site of catheterization, but Doppler imaging was normal. CONCLUSIONS: CA has a continuing role in the evaluation of cerebrovascular pathologies in children. Neurological complications are rare and local complications are not uncommon (around 5%), but are not usually serious.

Adolescent↗
PubMed2005

Imaging characteristics of primary cranial Ewing sarcoma.

BACKGROUND: Ewing sarcoma accounts for 10-15% of all childhood malignant bone tumours and is second in prevalence to osteosarcoma. The skull bones are an unusual site of origin of primary Ewing sarcoma in children. Previous reports concentrate on the neurosurgical aspects and relatively good outcome compared to other bone tumours of the calvarium. Reported cases mainly describe the imaging characteristics on CT. OBJECTIVE: To describe the MRI and CT features of primary cranial Ewing sarcoma. MATERIALS AND METHODS: The neuroimaging of three cases of primary cranial Ewing sarcoma are reviewed. RESULTS: Our three cases show an extra-axial mass that is high attenuation on CT and low signal on T2-weighted MRI. Haemorrhagic components, dural extension and contrast enhancement are also characteristic features. CONCLUSION: CT attenuation and magnetic resonance signal characteristics reflect sheets of densely packed cells seen in Ewing sarcoma.

Child↗
PubMed2005

Magnetic resonance image correlates of hemiparesis after neonatal and childhood middle cerebral artery stroke.

OBJECTIVE: Motor impairment after neonatal and childhood-onset ischemic stroke (IS) is common, although the prevalence and type of hemiparesis differs between the 2 age groups. Lesion topography is an important predictor of hemiparesis after neonatal IS, but it is not known if the same topographic predictors of adverse motor outcome apply to childhood-onset IS. We used a consistent approach to define lesion topography and evaluate motor outcome in both age groups to (1) investigate whether early topographic predictors of hemiparesis after unilateral middle cerebral artery-territory stroke are the same in neonates and older children and (2) compare the prevalence of dystonia and loss of independent finger movements between the 2 age groups. DESIGN: Twenty-eight patients with neonatal-onset IS (Hammersmith Hospital, London, United Kingdom) were studied together with 43 patients with childhood-onset IS (Great Ormond Street Hospital, London, United Kingdom). All patients had exclusive unilateral middle cerebral artery-territory IS. Lesion topography was studied by using the first magnetic resonance image acquired after the onset of symptoms and was coded for involvement of cerebral cortex (CC), posterior limb of the internal capsule (PLIC), basal ganglia (BG), and white matter. The primary outcome was hemiparesis, and secondary outcomes were dystonia and loss of age-appropriate independent finger movements. RESULTS: Hemiparesis was more common after childhood-onset IS (56%) than neonatal-onset IS (24%). In neonatal-onset IS, concomitant involvement of BG, CC, and PLIC predicts the development of hemiparesis (odds ratio: 99; 95% confidence interval: 5.2-1883.8), and no child with 1 or 2 of these structures involved developed hemiparesis. In contrast, in childhood-onset IS, concomitant BG, CC, and PLIC lesions tended to be associated with hemiparesis (9 of 11), but this adverse outcome was seen also among patients with 1- or 2-site involvement. However, hemiparesis was less likely if the infarction involved BG only (odds ratio: 0.162; 95% confidence interval: 0.036-0.729). Dystonia was present in 15 of 24 in the childhood-onset group with hemiparesis but was not seen after neonatal-onset IS. In both age groups upper-limb impairment was more severe than lower-limb impairment, with frequent loss of independent hand function among hemiparetic patients. CONCLUSIONS: In neonatal and childhood-onset IS, early magnetic resonance imaging provides useful prognostic information about subsequent motor outcome. There are differences in the functional response of the neuromotor system to injury between the 2 age groups that cannot be attributed to methodological differences alone.

Adolescent↗
PubMed2005

Surveillance imaging strategies following surgery and/or radiotherapy for childhood cerebellar low-grade astrocytoma.

OBJECT: The authors sought to evaluate surveillance strategies for the detection and monitoring of residual and recurrent disease in children with cerebellar low-grade astrocytomas (CLGAs) treated surgically or with radiotherapy. Patients were divided into three groups: (1) those in whom a "complete" resection was achieved; (2) those with residual disease with no immediate adjuvant therapy; and (3) those who received radiotherapy for residual/recurrent disease. METHODS: Magnetic resonance (MR) imaging studies and clinical data obtained in children with CLGA who presented between January 1988 and September 1998 were reviewed. Eighty-four children were followed for a mean period of 73 months (range 2-159 months). One child died. Of the 70 children in whom a complete resection was achieved, nine (13%) developed a recurrence detected by surveillance imaging at 6, 8, 9, 9, 13, 27, 39, 44, and 47 months, respectively. Following an incomplete resection, radiologically detected tumor progression leading to further treatment was detected at 7, 9, 12, 13, and 20 months, respectively, and an additional six tumors regressed or stablized. In 11 of 12 children treated with radiotherapy, stabilization/regression occurred radiologically at a mean of 14.9 months. CONCLUSIONS: The authors recommend surveillance MR imaging in children treated for CLGA at 6 months and 1, 2, 3.5, and 5 years following a complete resection and after radiotherapy performed either initially or following recurrence. For follow up of residual tumor, 6-month interval imaging for at least 3 years, yearly images for another 2 years, and subsequent 2-year imaging is recommended.

Adolescent↗
PubMed2003

Surveillance neuroimaging of intracranial medulloblastoma in children: how effective, how often, and for how long?

OBJECT: The goal of this paper was to review brain and spine images obtained in children with medulloblastomas to determine the risk factors for tumor recurrence and to assess the impact of surveillance imaging on patient outcomes among patients who remain alive 1 month postsurgery. METHODS: Imaging studies and clinical data obtained in children with medulloblastomas, who presented between January 1987 and August 1998, were retrospectively reviewed. Images were termed surveillance if they were follow-up studies and symptom prompted if they were obtained to investigate new symptoms. One hundred seven patients (mean age 6 years and 3 months, range 2 months-15 years and 6 months) were entered into the study. Fifty-three children experienced tumor recurrence; 41 had one recurrence, nine had two, and three had three recurrences. Surveillance imaging revealed 10 of the first 53 recurrences and 15 of all 68 recurrences. When the first recurrence was identified by the emergence of symptoms (42 patients), the children tended to survive for a shorter time (hazard ratio 3.72, 95% confidence interval 1.42-9.76, p = 0.008) than children in whom the first recurrence was detected before symptoms occurred (10 patients). The median survival time following symptomatic tumor recurrence was 4 months and that after surveillance-detected tumor recurrence was 17 months. The median increased survival time among patients whose recurrence was asymptomatic and identified by imaging studies was 13 months, more than half the mean time between surveillance imaging sessions. Incomplete tumor resection was associated with a significantly reduced time to recurrence (p = 0.048) and to death (p = 0.002). The number of recurrences that were experienced was associated with a reduced time to death (p < 0.001). CONCLUSIONS: Surveillance imaging is associated with an increase in survival in children with medulloblastomas. More frequent surveillance imaging in children with incomplete tumor excision and recurrent disease may further improve the length of survival.

Adolescent↗