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2.  Pathophysiology of persistent syringomyelia after decompressive craniocervical surgery 
Journal of neurosurgery. Spine  2010;13(6):10.3171/2010.6.SPINE10200.
Object
Craniocervical decompression for Chiari malformation Type I (CM-I) and syringomyelia has been reported to fail in 10%–40% of patients. The present prospective clinical study was designed to test the hypothesis that in cases in which syringomyelia persists after surgery, craniocervical decompression relieves neither the physiological block at the foramen magnum nor the mechanism of syringomyelia progression.
Methods
The authors prospectively evaluated and treated 16 patients with CM-I who had persistent syringomyelia despite previous craniocervical decompression. Testing before surgery included the following: 1) clinical examination; 2) evaluation of the anatomy using T1-weighted MR imaging; 3) assessment of the syrinx and CSF velocity and flow using cine phase-contrast MR imaging; and 4) appraisal of the lumbar and cervical subarachnoid pressures at rest, during a Valsalva maneuver, during jugular compression, and following the removal of CSF (CSF compliance measurement). During surgery, ultrasonography was performed to observe the motion of the cerebellar tonsils and syrinx walls; pressure measurements were obtained from the intracranial and lumbar intrathecal spaces. The surgical procedure involved enlarging the previous craniectomy and performing an expansile duraplasty with autologous pericranium. Three to 6 months after surgery, clinical examination, MR imaging, and CSF pressure recordings were repeated. Clinical examination and MR imaging studies were then repeated annually.
Results
Before reexploration, patients had a decreased size of the CSF pathways and a partial blockage in CSF transmission at the foramen magnum. Cervical subarachnoid pressure and pulse pressure were abnormally elevated. During surgery, ultrasonographic imaging demonstrated active pulsation of the cerebellar tonsils, with the tonsils descending during cardiac systole and concomitant narrowing of the upper pole of the syrinx. Three months after reoperation, patency of the CSF pathways was restored and pressure transmission was improved. The flow of syrinx fluid and the diameter of the syrinx decreased after surgery in 15 of 16 patients.
Conclusions
Persistent blockage of the CSF pathways at the foramen magnum resulted in increased pulsation of the cerebellar tonsils, which acted on a partially enclosed cervical subarachnoid space to create elevated cervical CSF pressure waves, which in turn affected the external surface of the spinal cord to force CSF into the spinal cord through the Virchow-Robin spaces and to propel the syrinx fluid caudally, leading to syrinx progression. A surgical procedure that reestablished the CSF pathways at the foramen magnum reversed this pathophysiological mechanism and resolved syringomyelia. Elucidating the pathophysiology of persistent syringomyelia has implications for its primary and secondary treatment.
doi:10.3171/2010.6.SPINE10200
PMCID: PMC3822767  PMID: 21121751
syringomyelia; therapeutics; radiography; physiology; Arnold-Chiari malformation, Type I
3.  Recurrent left atrial myxomas in Carney complex: a genetic cause of multiple strokes that can be prevented 
Background
Intracardiac myxomas in Carney complex are significant causes of cardiovascular morbidity and mortality through embolic stroke and heart failure. The genetic, clinical and laboratory characteristics of Carney complex-related strokes from atrial myxomas have not been described before. The PRKAR1A gene is mutated in more than 60% of the cases of Carney complex.
Methods and Results
We studied patients with strokes and cardiac myxomas that were hospitalized in our institution and elsewhere: a total of 7 patients with 16 recurrent atrial myxomas and more than 14 episodes of strokes were identified. Neurological deficits were reported; in one patient, an aneurysm developed at the site of a previous stroke. All patients were female, most had presented with Cushing syndrome, and all had additional tumors or other Carney complex manifestations. Other than gender, although there was a trend for patients being overweight and hypertensive, no other risk factors were identified. A total of 5 patients (71%) had a PRKAR1A mutation; all mutations (c418_419delCA, c.340delG/p.Val113fsX15, c.353_365del13/p.Ile118fsX6, c.491_492delTG/p.Val164fsX4, c.177+1G>A) were located in exons 3–5 and introns 2–3, and all led to a non-sense PRKAR1A mRNA.
Conclusions
Female Carney complex patients appear to be at a high risk for recurrent atrial myxomas that lead to multiple strokes. Early identification of a female patient with Carney complex is of paramount importance for the early diagnosis of atrial myxomas and the prevention of strokes.
doi:10.1016/j.jstrokecerebrovasdis.2012.01.006
PMCID: PMC3369015  PMID: 22341669
4.  Pathophysiology of primary spinal syringomyelia 
Journal of neurosurgery. Spine  2012;17(5):367-380.
Object
The pathogenesis of syringomyelia in patients with an associated spinal lesion is incompletely understood. The authors hypothesized that in primary spinal syringomyelia, a subarachnoid block effectively shortens the length of the spinal subarachnoid space (SAS), reducing compliance and the ability of the spinal theca to dampen the subarachnoid CSF pressure waves produced by brain expansion during cardiac systole. This creates exaggerated spinal subarachnoid pressure waves during every heartbeat that act on the spinal cord above the block to drive CSF into the spinal cord and create a syrinx. After a syrinx is formed, enlarged subarachnoid pressure waves compress the external surface of the spinal cord, propel the syrinx fluid, and promote syrinx progression.
Methods
To elucidate the pathophysiology, the authors prospectively studied 36 adult patients with spinal lesions obstructing the spinal SAS. Testing before surgery included clinical examination; evaluation of anatomy on T1-weighted MRI; measurement of lumbar and cervical subarachnoid mean and pulse pressures at rest, during Valsalva maneuver, during jugular compression, and after removal of CSF (CSF compliance measurement); and evaluation with CT myelography. During surgery, pressure measurements from the SAS above the level of the lesion and the lumbar intrathecal space below the lesion were obtained, and cardiac-gated ultrasonography was performed. One week after surgery, CT myelography was repeated. Three months after surgery, clinical examination, T1-weighted MRI, and CSF pressure recordings (cervical and lumbar) were repeated. Clinical examination and MRI studies were repeated annually thereafter. Findings in patients were compared with those obtained in a group of 18 healthy individuals who had already undergone T1-weighted MRI, cine MRI, and cervical and lumbar subarachnoid pressure testing.
Results
In syringomyelia patients compared with healthy volunteers, cervical subarachnoid pulse pressure was increased (2.7 ± 1.2 vs 1.6 ± 0.6 mm Hg, respectively; p = 0.004), pressure transmission to the thecal sac below the block was reduced, and spinal CSF compliance was decreased. Intraoperative ultrasonography confirmed that pulse pressure waves compressed the outer surface of the spinal cord superior to regions of obstruction of the subarachnoid space.
Conclusions
These findings are consistent with the theory that a spinal subarachnoid block increases spinal subarachnoid pulse pressure above the block, producing a pressure differential across the obstructed segment of the SAS, which results in syrinx formation and progression. These findings are similar to the results of the authors' previous studies that examined the pathophysiology of syringomyelia associated with obstruction of the SAS at the foramen magnum in the Chiari Type I malformation and indicate that a common mechanism, rather than different, separate mechanisms, underlies syrinx formation in these two entities. Clinical trial registration no.: NCT00011245. (http://thejns.org/doi/abs/10.3171/2012.8.SPINE111059)
doi:10.3171/2012.8.SPINE111059
PMCID: PMC3787878  PMID: 22958075
syringomyelia; physiology; ultrasonography; surgery; cerebrospinal fluid; magnetic resonance imaging; myelography
5.  Molecular imaging of pediatric brain tumors: comparison of tumor metabolism using 18F-FDG-PET and MRSI 
Journal of neuro-oncology  2012;109(3):521-527.
Purpose
Magnetic resonance spectroscopic imaging (MRSI) and 18F-Fluorodeoxyglucose positron emission tomography (FDG-PET) are non-invasive imaging techniques routinely used to evaluate tumor malignancy in adults with brain tumors. We compared the metabolic activity of pediatric brain tumors using FDG-PET and MRSI.
Methods
Children (n=37) diagnosed with a primary brain tumor underwent FDG-PET and MRSI within two weeks of each other. Tumor metabolism was classified as inactive, active or highly active using the maximum choline:N-acetyl-asparate (Cho:NAA) on MRSI and the highest tumor uptake on FDG-PET. A voxel-wise comparison was used to evaluate the area with the greatest abnormal metabolism. Agreement between methods was assessed using the percent agreement and the kappa statistic (κ).
Results
Pediatric brain tumors were metabolically heterogeneous on FDG-PET and MRSI studies. Active tumor metabolism was observed more frequently using MRSI compared to FDG-PET, and agreement in tumor classification was weak (κ=0.16, p=0.12), with 42% agreement (95% CI= 25 – 61%). Voxel-wise comparison for identifying the area of greatest metabolic activity showed overlap in the majority (62%) of studies, though exact agreement between techniques was low (29.4%, 95% CI = 15.1 – 47.5%).
Conclusion
These results indicate that FDG-PET and MRSI detect similar but not always identical regions of tumor activity, and there is little agreement in the degree of tumor metabolic activity between the two techniques.
doi:10.1007/s11060-012-0918-0
PMCID: PMC3482688  PMID: 22760419
pediatric; brain tumor; 18F-FDG-PET; MR spectroscopy; metabolism
6.  The influence of DNA repair on neurological degeneration, cachexia, skin cancer and internal neoplasms: autopsy report of four xeroderma pigmentosum patients (XP-A, XP-C and XP-D) 
Background
To investigate the association of DNA nucleotide excision repair (NER) defects with neurological degeneration, cachexia and cancer, we performed autopsies on 4 adult xeroderma pigmentosum (XP) patients with different clinical features and defects in NER complementation groups XP-A, XP-C or XP-D.
Results
The XP-A (XP12BE) and XP-D (XP18BE) patients exhibited progressive neurological deterioration with sensorineural hearing loss. The clinical spectrum encompassed severe cachexia in the XP-A (XP12BE) patient, numerous skin cancers in the XP-A and two XP-C (XP24BE and XP1BE) patients and only few skin cancers in the XP-D patient. Two XP-C patients developed internal neoplasms including glioblastoma in XP24BE and uterine adenocarcinoma in XP1BE. At autopsy, the brains of the 44 yr XP-A and the 45 yr XP-D patients were profoundly atrophic and characterized microscopically by diffuse neuronal loss, myelin pallor and gliosis. Unlike the XP-A patient, the XP-D patient had a thickened calvarium, and the brain showed vacuolization of the neuropil in the cerebrum, cerebellum and brainstem, and patchy Purkinje cell loss. Axonal neuropathy and chronic denervation atrophy of the skeletal muscles were observed in the XP-A patient, but not in the XP-D patient.
Conclusions
These clinical manifestations and autopsy findings indicate advanced involvement of the central and peripheral nervous system. Despite similar defects in DNA repair, different clinicopathological phenotypes are seen in the four cases, and therefore distinct patterns of neurodegeneration characterize XP-D, XP-A and XP-C patients.
doi:10.1186/2051-5960-1-4
PMCID: PMC3776212  PMID: 24252196
DNA damage; DNA repair; Neurodegeneration; Glioblastoma; Cachexia
7.  The complex of myxomas, spotty skin pigmentation and endocrine overactivity (Carney complex): imaging findings with clinical and pathological correlation 
Insights into Imaging  2013;4(1):119-133.
The complex of myxomas, spotty skin pigmentation and endocrine overactivity, or Carney complex (CNC), is a familial multiple endocrine neoplasia and lentiginosis syndrome. CNC is inherited in an autosomal dominant manner and is genetically heterogeneous. Its features overlap those of McCune-Albright syndrome and other multiple endocrine neoplasia (MEN) syndromes. Spotty skin pigmentation is the major clinical manifestation of the syndrome, followed by multicentric heart myxomas, which occur at a young age and are the lethal component of the disease. Myxomas may also occur on the skin (eyelid, external ear canal and nipple) and the breast. Breast myxomas, when present, are multiple and bilateral among female CNC patients, an entity which is also described as “breast-myxomatosis” and is a characteristic feature of the syndrome. Affected CNC patients often have tumours of two or more endocrine glands, including primary pigmented nodular adrenocortical disease (PPNAD), an adrenocorticotropin hormone (ACTH)-independent cause of Cushing’s syndrome, growth hormone (GH)-secreting and prolactin (PRL)-secreting pituitary adenomas, thyroid adenomas or carcinomas, testicular neoplasms (large-cell calcifying Sertoli cell tumours [LCCSCT]) and ovarian lesions (cysts and cancinomas). Additional infrequent but characteristic manifestations of CNC are psammomatous melanotic schwannomas (PMS), breast ductal adenomas (DAs) with tubular features, and osteochondromyxomas or “Carney bone tumour”.
Teaching Points
• Almost 60 % of the known CNC kindreds have a germline inactivating mutations in the PRKAR1A gene.
• Spotty skin pigmentation is the major clinical manifestation of CNC, followed by heart myxomas.
• Indicative imaging signs of PPNAD are contour abnormality and hypodense spots within the gland.
• Two breast tumours may present in CNC: myxoid fibroadenomas (breast myxomatosis) and ductal adenomas.
• Additional findings of CNC are psammomatous melanotic schwannomas (PMSs) and osteochondromyxomas.
doi:10.1007/s13244-012-0208-6
PMCID: PMC3579989  PMID: 23315333
Carney complex; Protein kinase A; Spotty skin pigmentation; Myxoma; Primary pigmented nodular adrenocortical disease; Large-cell calcifying sertoli cell tumour; Psammomatous melanotic schwannoma; Ductal adenoma; Osteochondromyxoma
8.  Neonatal Diagnosis and Treatment of Menkes Disease 
The New England journal of medicine  2008;358(6):605-614.
BACKGROUND
Menkes disease is a fatal neurodegenerative disorder of infancy caused by diverse mutations in a copper-transport gene, ATP7A. Early treatment with copper injections may prevent death and illness, but presymptomatic detection is hindered by the inadequate sensitivity and specificity of diagnostic tests. Exploiting the deficiency of a copper enzyme, dopamine-β-hydroxylase, we prospectively evaluated the diagnostic usefulness of plasma neurochemical levels, assessed the clinical effect of early detection, and investigated the molecular bases for treatment outcomes.
METHODS
Between May 1997 and July 2005, we measured plasma dopamine, norepinephrine, dihydroxyphenylacetic acid, and dihydroxyphenylglycol in 81 infants at risk. In 12 newborns who met the eligibility criteria and began copper-replacement therapy within 22 days after birth, we tracked survival and neurodevelopment longitudinally for 1.5 to 8 years. We characterized ATP7A mutations using yeast complementation, reverse-transcriptase–polymerase-chain-reaction analysis, and immunohistochemical analysis.
RESULTS
Of 81 infants at risk, 46 had abnormal neurochemical findings indicating low dopamine-β-hydroxylase activity. On the basis of longitudinal follow-up, patients were classified as affected or unaffected by Menkes disease, and the neurochemical profiles were shown to have high sensitivity and specificity for detecting disease. Among 12 newborns with positive screening tests who were treated early with copper, survival at a median follow-up of 4.6 years was 92%, as compared with 13% at a median follow-up of 1.8 years for a historical control group of 15 late-diagnosis and late-treatment patients. Two of the 12 patients had normal neurodevelopment and brain myelination; 1 of these patients had a mutation that complemented a Saccharomyces cerevisiae copper-transport mutation, indicating partial ATPase activity, and the other had a mutation that allowed some correct ATP7A splicing.
CONCLUSIONS
Neonatal diagnosis of Menkes disease by plasma neurochemical measurements and early treatment with copper may improve clinical outcomes. Affected newborns who have mutations that do not completely abrogate ATP7A function may be especially responsive to early copper treatment.
doi:10.1056/NEJMoa070613
PMCID: PMC3477514  PMID: 18256395
9.  BRITTLE HAIR, DEVELOPMENTAL DELAY, NEUROLOGIC ABNORMALITIES AND PHOTOSENSITIVITY IN A 4 YEAR OLD GIRL 
doi:10.1016/j.jaad.2010.03.041
PMCID: PMC3464913  PMID: 20633800
DNA repair; trichothiodystrophy; genetic diseases; hair abnormalities; recurrent infections; collodion membrane; erythroderma; congenital ichthyosis
10.  Reversible posterior encephalopathy syndrome associated with micronodular adrenocortical disease and Cushing syndrome 
European journal of pediatrics  2009;169(1):125-126.
We report the case of a 6-year-old female with ACTH-independent Cushing syndrome secondary to bilateral adrenal nodular hyperplasia, who presented with hypertension and seizures, and was found have MRI changes consistent with posterior reversible encephalopathy syndrome (PRES). The patient received anti-hypertensive medication and a bilateral adrenalectomy was performed. One month later, resolution of her brain MRI changes were seen. This is the first case described in the literature of a patient with Cushing syndrome and PRES. We review the link between hypertension and Cushing syndrome, along with the pathophysiology of PRES and emphasize the importance of early recognition and treatment of hypertension in pediatric patients with Cushing syndrome to avoid possible cerebrovascular complications that may be related to a hypertensive event.
doi:10.1007/s00431-009-0990-4
PMCID: PMC3124700  PMID: 19415327
Cushing syndrome; hypertension; adrenal tumors; hyperplasia
11.  A change in pituitary MRI protocol detects ACTH-secreting tumours in patients with previously negative results 
Clinical endocrinology  2009;72(4):502-506.
Objective
While detection of pituitary tumors with magnetic resonance imaging (MRI) may reduce diagnostic costs and improve surgical outcomes for patients with Cushing's disease, the optimal T1-weighted spin echo MRI protocol remains unknown. We hypothesized that specific MR scanning parameters influence detection of corticotropinomas.
Design and patients
Between December 1997 and November 2004, 21 of 84 consecutive patients with Cushing's disease had a falsely negative initial pituitary MRI study and a lesion identified subsequently at the National Institutes of Health Clinical Center. This study retrospectively reviewed and compared technical parameters used for the two pituitary T1-weighted spin echo MRIs in 18 patients with available scans.
Measurements
Repetition time (TR)/echo times (TE), field of view (FOV), matrix size, magnetic field strength, slice thickness, use of Gadolinium contrast and the time interval between studies were recorded.
Results
The MRI inter-scan interval was 5.4 ± 1.1 months. All scans used gadolinium, matrix sizes were similar and nearly all had 3 mm slice thickness. Parameters that differed between the NIH and outside scans were: TR (400 ms vs. 492±19 ms, P = 0.0002); TE (10.3 ± 0.5 vs. 17.2 ms ± 1.2 ms, P = 0.0003); FOV (12×12 cm vs.17±0.6 × 18±0.7 cm, P<0.0001). Immunohistochemistry of tumors resected at transsphenoidal surgery confirmed all tob be corticotropinomas.
Conclusions
Not all “T1-weighted spin echo” scans are equally accurate. MRI technique, particularly FOV and TR/TE value, influences results. We recommend that endocrinologists consider pituitary MRI parameters when interpreting the results.
doi:10.1111/j.1365-2265.2009.03646.x
PMCID: PMC2866063  PMID: 19500112
Magnetic resonance imaging; Cushing's disease; diagnosis
12.  Lymphocytic Vasculitis Involving the Central Nervous System Occurs in Patients with X-linked Lymphoproliferative Disease in the Absence of Epstein-Barr Virus Infection 
Pediatric blood & cancer  2009;53(6):1120-1123.
X-linked lymphoproliferative disease (XLP) is an immunodeficiency caused by defects in the adaptor molecule SAP. The manifestations of XLP generally occur following Epstein-Barr virus (EBV) infection and include fulminant mononucleosis, hypogammaglobulinemia and lymphoma. In this report, we describe two unrelated patients with fatal T cell-mediated central nervous system vasculitis for whom repeated serologic and molecular testing for EBV was negative. In both patients, clonal T cell populations were observed, but neither demonstrated evidence of lymphoma. Thus, loss of SAP function can lead to dysregulated immune responses characterized by the uncontrolled expansion and activation of T cells independent of EBV infection.
doi:10.1002/pbc.22185
PMCID: PMC2745493  PMID: 19621458
X-linked lymphoproliferative disease; central nervous system; vasculitis
13.  Clinical Outcomes in Menkes Disease Patients with a Copper-Responsive ATP7A Mutation, G727R 
Molecular genetics and metabolism  2008;95(3):174-181.
Menkes disease is a fatal neurodegenerative disorder of infancy caused by defects in an X-linked copper transport gene, ATP7A. Evidence from a recent clinical trial indicates that favorable response to early treatment of this disorder with copper injections involves mutations that retain some copper transport capacity. In three unrelated infants, we identified the same mutation, G727R, in the second transmembrane segment of the ATP7A gene product that complemented a S. cerevisiae copper transport mutant, consistent with partial copper transport activity. Quantitative reverse transcription-polymerase chain reaction studies showed approximately normal levels of ATP7AG727R transcript in two patients’ fibroblasts compared to wild type controls, but Western blot analyses showed markedly reduced quantities of ATP7A protein, suggesting post-translational degradation. We confirmed the latter by comparing degradation rates of mutant and wild type ATP7A via cyclohexamide treatment of cultured fibroblasts; half-life of the G727R mutant was 2.9 hr and for the wild-type, 11.4 hr. We also documented a X-box binding protein 1 splice variant in G727R cells - known to be associated with the cellular misfolded protein response. Patient A, diagnosed 6 months of age, began treatment at 228 days (7.6 mos) of age. At his current age (2 years), his overall neurodevelopment remains at a 2 to 4 month level. In contrast, patients B and C were diagnosed in the neonatal period, began treatment within 25 days of age, and show near normal neurodevelopment at their current ages, 3 years (B), and 7 months (C). The poor clinical outcome in patient A with the same missense mutation as patients A and B with near normal oucomes, confirms the importance of early medical intervention in Menkes disease and highlights the critical potential benefit of newborn screening for this disorder.
doi:10.1016/j.ymgme.2008.06.015
PMCID: PMC2654537  PMID: 18752978
14.  Surgical management of Cushing Syndrome secondary to micronodular adrenal hyperplasia 
Surgery  2008;143(6):750-758.
Background
We reviewed our experience with micronodular adrenal hyperplasia (MAH), its pigmented variant primary pigmented nodular adrenocortical disease (PPNAD), and the association with Carney’s Complex (CNC) in order to better characterize the disorders.
Methods
This study is a retrospective analysis of clinical data and operative reports of 34 patients identified with MAH and/or PPNAD who underwent resection between 1969 and 2006 at the Clinical Research Center, an inpatient research hospital, at the National Institutes of Health. Symptoms and anthropometric and biochemical data were used to evaluate effect of resection.
Results
Fifteen patients (44%) presented as adults and 19 (56%) as children. Twenty five patients (74%) presented with non-cyclic Cushing syndrome and nine patients (26%) presented with cyclic Cushing Syndrome. Thirty one patients underwent bilateral resection; this was curative biochemically in 30 patients. Fourteen operations were performed laparoscopically (41%), and 20 were perfomed as open resections (59%). There was one post-operative complication in the laparoscopic group (7%) and 6 complications in the open group (30%) (p=0.20). Follow-up was available for 25 patients (74%). Statistically significant improvements in anthropometrics were observed for both adults and children. The most frequent manifestation of CNC requiring additional operation was cardiac myxoma which was associated strongly with an atypical (cyclic) presentation of Cushing Syndrome (p=0.009).
Conclusion
Cushing Syndrome due to MAH and PPNAD may be cured by bilateral adrenal resection. All patients should be screened for manifestations of CNC at the time of adrenal diagnosis with particular attention to cardiac disease.
doi:10.1016/j.surg.2008.03.022
PMCID: PMC2601697  PMID: 18549891
15.  XERODERMA PIGMENTOSUM, TRICHOTHIODYSTROPHY AND COCKAYNE SYNDROME: A COMPLEX GENOTYPE-PHENOTYPE RELATIONSHIP 
Neuroscience  2007;145(4):1388-1396.
Patients with the rare genetic disorders, xeroderma pigmentosum (XP), trichothiodystrophy (TTD) and Cockayne syndrome (CS) have defects in DNA nucleotide excision repair (NER). The NER pathway involves at least 28 genes. Three NER genes are also part of the basal transcription factor, TFIIH. Mutations in 11 NER genes have been associated with clinical diseases with at least 8 overlapping phenotypes. The clinical features of these patients have some similarities and but also have marked differences. NER is involved in protection against sunlight induced DNA damage. While XP patients have 1000-fold increase in susceptibility to skin cancer, TTD and CS patients have normal skin cancer risk. Several of the genes involved in NER also affect somatic growth and development. Some patients have short stature and immature sexual development. TTD patients have sulfur deficient brittle hair. Progressive sensorineural deafness is an early feature of XP and CS. Many of these clinical diseases are associated with developmental delay and progressive neurological degeneration. The main neuropathology of XP is a primary neuronal degeneration. In contrast, CS and TTD patients have reduced myelination of the brain. These complex neurological abnormalities are not related to sunlight exposure but may be caused by developmental defects as well as faulty repair of DNA damage to neuronal cells induced by oxidative metabolism or other endogenous processes.
doi:10.1016/j.neuroscience.2006.12.020
PMCID: PMC2288663  PMID: 17276014
cancer; neurodegeneration; DNA repair; genetic disease; neurocutaneous diseases
16.  Magnetic resonance imaging and computed tomography in emergency assessment of patients with suspected acute stroke: a prospective comparison 
Lancet  2007;369(9558):293-298.
Summary
Background
Although the use of magnetic resonance imaging (MRI) for the diagnosis of acute stroke is increasing, this method has not proved more effective than computed tomography (CT) in the emergency setting. We aimed to prospectively compare CT and MRI for emergency diagnosis of acute stroke.
Methods
We did a single-centre, prospective, blind comparison of non-contrast CT and MRI (with diffusion-weighted and susceptibility weighted images) in a consecutive series of patients referred for emergency assessment of suspected acute stroke. Scans were independently interpreted by four experts, who were unaware of clinical information, MRI-CT pairings, and follow-up imaging.
Results
356 patients, 217 of whom had a final clinical diagnosis of acute stroke, were assessed. MRI detected acute stroke (ischaemic or haemorrhagic), acute ischaemic stroke, and chronic haemorrhage more frequently than did CT (p<0.0001, for all comparisons). MRI was similar to CT for the detection of acute intracranial haemorrhage. MRI detected acute ischaemic stroke in 164 of 356 patients (46%; 95% CI 41-51%), compared with CT in 35 of 356 patients (10%; 7-14%). In the subset of patients scanned within 3 h of symptom onset, MRI detected acute ischaemic stroke in 41 of 90 patients (46%; 35-56%); CT in 6 of 90 (7%; 3-14%). Relative to the final clinical diagnosis, MRI had a sensitivity of 83% (181 of 217; 78-88%) and CT of 26% (56 of 217; 20-32%) for the diagnosis of any acute stroke.
Interpretation
MRI is better than CT for detection of acute ischaemia, and can detect acute and chronic haemorrhage; therefore it should be the preferred test for accurate diagnosis of patients with suspected acute stroke. Because our patient sample encompassed the range of disease that is likely to be encountered in emergency cases of suspected stroke, our results are directly applicable to clinical practice.
doi:10.1016/S0140-6736(07)60151-2
PMCID: PMC1859855  PMID: 17258669

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