C C Tchoyoson Lim | Duke-NUS Graduate Medical School (original) (raw)
Papers by C C Tchoyoson Lim
comp.nus.edu.sg
This paper proposes a generative model approach to automatically annotate medical images to impro... more This paper proposes a generative model approach to automatically annotate medical images to improve the efficiency and effectiveness of image retrieval systems for teaching, research, and diagnosis. The generative model captures the probabilistic relationships among relevant classification tags, tentative lesion patterns, and selected input features. Operating on the imperfect segmentation results of input images, the probabilistic framework can effectively handle the inherent uncertainties in the images and insufficient information in the training data. Preliminary assessment in the ischemic stroke subtype classification shows that the proposed system is capable of generating the relevant tags for ischemic stroke brain images. The main benefit of this approach is its scalability; the method can be applied in large image databases as it requires only minimal manual labeling of the training data and does not demand high-precision segmentation of the images.
Radiographics, Nov 1, 2005
ABSTRACT A new method has been developed for multimedia enhancement of electronic teaching files ... more ABSTRACT A new method has been developed for multimedia enhancement of electronic teaching files created by using the standard protocols and formats offered by the Medical Imaging Resource Center (MIRC) project of the Radiological Society of North America. The typical MIRC electronic teaching file consists of static pages only; with the new method, audio and visual content may be added to the MIRC electronic teaching file so that the entire image interpretation process can be recorded for teaching purposes. With an efficient system for encoding the audiovisual record of on-screen manipulation of radiologic images, the multimedia teaching files generated are small enough to be transmitted via the Internet with acceptable resolution. Students may respond with the addition of new audio and visual content and thereby participate in a discussion about a particular case. MIRC electronic teaching files with multimedia enhancement have the potential to augment the effectiveness of diagnostic radiology teaching.
RadioGraphics, 2005
A new method has been developed for multimedia enhancement of electronic teaching files created b... more A new method has been developed for multimedia enhancement of electronic teaching files created by using the standard protocols and formats offered by the Medical Imaging Resource Center (MIRC) project of the Radiological Society of North America. The typical MIRC electronic teaching file consists of static pages only; with the new method, audio and visual content may be added to the MIRC electronic teaching file so that the entire image interpretation process can be recorded for teaching purposes. With an efficient system for encoding the audiovisual record of on-screen manipulation of radiologic images, the multimedia teaching files generated are small enough to be transmitted via the Internet with acceptable resolution. Students may respond with the addition of new audio and visual content and thereby participate in a discussion about a particular case. MIRC electronic teaching files with multimedia enhancement have the potential to augment the effectiveness of diagnostic radiology teaching.
Pediatric Neurology, 2007
Both the syndrome of mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (... more Both the syndrome of mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS syndrome) and Hashimoto's encephalopathy can present with nonspecific encephalopathy. Hashimoto's encephalopathy is an association of steroid-responsive encephalopathy with elevated thyroid peroxidase antibodies. Steroid-responsive encephalopathy, however, is not characteristic of the MELAS syndrome, which typically presents with stroke-like episodes and lactic acidosis in cerebrospinal fluid and blood. Here, a patient is described with goiter, recurrent encephalopathy and elevated thyroid peroxidase antibodies who apparently responded to steroid therapy; however, magnetic resonance imaging was atypical for Hashimoto's encephalopathy, and she was diagnosed with MELAS syndrome. This syndrome can present with apparent steroid-responsive encephalopathy and elevated thyroid peroxidase antibodies, mimicking Hashimoto's encephalopathy, and should be suspected if lactic acidosis is present and typical features are detected on magnetic resonance imaging.
Journal of Neurology, 2008
Clinical diagnosis of CJD remains important due to lack of access to a genetic or histopathologic... more Clinical diagnosis of CJD remains important due to lack of access to a genetic or histopathological diagnosis. Using current WHO criteria, diagnostic certainty can be increased from "possible" to "probable" CJD if periodic complexes are recorded on EEG. To study the correlation between patterns of MRI-DWI hyperintensity and typical EEG findings among patients with CJD. Demographics, clinical findings, MRI-DWI and EEG findings of CJD patients were retrospectively reviewed. A total of 14 patients ranging in age from 35 to 81 years were identified. All had dementia and cerebellar ataxia. Psychiatric manifestations were seen in 5 patients. Seven patients had both cortical and striatal DWI changes, five had isolated cortical DWI changes and two had isolated striatal DWI changes. All twelve patients with cortical DWI changes also had periodic EEG changes. In ten, periodic EEG was recorded within seven days of the DWI. The two patients with isolated striatal DWI changes did not develop periodic EEG complexes despite serial EEG recordings, 40 and 88 days from their respective DWI scans. Serial EEGs are not useful for patients with isolated striatal DWI hyperintensity but will increase diagnostic certainty from "possible" to probable" CJD for patients with cortical DWI hyperintensity.
Singapore medical journal
We describe a seven-year-old chinese girl with NF1 and unilateral MMS with multiple hyperintensit... more We describe a seven-year-old chinese girl with NF1 and unilateral MMS with multiple hyperintensities on T2-weighted magnetic resonance (MR) images. The ischaemic lesions in the ipsilateral white matter were hypointense on fluid attenuated inversion recovery (FLAIR) MR images, in contrast to the hyperintense "unidentified bright objects" (UBOs) of NF1. Neuroradiologists should be aware of associated MMS in NF1 patients, and distinguish the effects of ischaemia from UBOs, especially on FLAIR MR imaging.
Annals of the Academy of Medicine, Singapore
Introduction: Deep venous thrombosis (DVT) is thought to be less common in Asians than in the Cau... more Introduction: Deep venous thrombosis (DVT) is thought to be less common in Asians than in the Caucasian population. The incidence of asymptomatic DVT in high-risk groups in the Asian population has not been well studied. While DVT incidence among Caucasian stroke patients has been extensively studied and the need for prophylaxis established, the lack of data in Asian patients leaves physicians with no firm basis for adopting prophylactic protocols in the local population. Our aim was to prospectively establish the incidence of early DVT in immobilised stroke patients in a heterogenous Asian population. Materials and Methods: We screened 44 patients with significant hemiplegia from acute stroke. Doppler ultrasound, the currently accepted method of investigation for DVT, was used to study patients on admission and at 1 week post-stroke. While there was no standard prophylactic regime in use, none of the patients received heparin and only 2 were given compression stockings. Results: The incidence of DVT at 1 week was 2.4%. Review at 1 month detected another patient with DVT, bringing the overall incidence at 1 month to 4.8%. This is lower than in Caucasian populations, but is similar to another local study on a different group of high-risk patients. Conclusion: The low incidence of early DVT in hospitalised stroke patients of Asian ethnicity does not justify routine screening for this population. Further research to validate this should ideally include a comparison test for DVT as ultrasound may have inherently lower sensitivity in an asymptomatic population.
Neurology Asia
Advanced diffusion weighted (DW) MRI of the brain in the fatal outbreak of Nipah viral encephalit... more Advanced diffusion weighted (DW) MRI of the brain in the fatal outbreak of Nipah viral encephalitis among pig workers in Malaysia and Singapore revealed a pattern similar to ischaemic infarction caused by obstruction of small cerebral blood vessels. However, relapse and late-onset cases in Malaysia, and other outbreaks of Nipah virus in Bangladesh and the Hendra virus infection in Australia, showed a different MRI pattern of predominantly confluent cortical lesions. MRI was useful in characterizing the disease in acute infection, as well as detection of spine abnormalities and subclinical infection.
Annals of the Academy of Medicine, Singapore
The aim of this study was to review the clinical, computed tomography (CT) and magnetic resonance... more The aim of this study was to review the clinical, computed tomography (CT) and magnetic resonance imaging (MRI) diagnosis and the frequency of positive neuroimaging findings in patients with cerebral venous thrombosis (CVT) involving the superior sagittal sinus. A clinical and radiological database of patients with final diagnosis of CVT was compiled from the inpatient hospital information service of a tertiary neurological hospital over 5 years. CT and MRI studies in 22 patients were retrospectively examined for direct signs of venous sinus thrombosis and for complications of CVT. The diagnosis of CVT before and after CT and MRI was reviewed. Clinical diagnosis of possible CVT was suspected in only 1 patient. When the diagnosis was not suspected, CT diagnosis was difficult and there was a high false negative rate of 52.6%. MRI fared better, but the false negative rate was still 11%. Directs signs of venous sinus thrombosis such as the triangle sign, empty delta sign on CT and loss ...
Singapore medical journal, 2014
A 58-year-old Indian woman presented with asystole after an episode of haemetemesis, with a patie... more A 58-year-old Indian woman presented with asystole after an episode of haemetemesis, with a patient downtime of 20 mins. After initial resuscitation efforts, computed tomography of the brain, obtained to evaluate neurological injury, demonstrated evidence of severe hypoxic ischaemic brain injury. The imaging features of hypoxic ischaemic brain injury and the potential pitfalls with regard to image interpretation are herein discussed.
Neuroimaging clinics of North America, 2011
The myelin sheath and oligodendrocytes in the brain may be damaged by autoimmune-mediated inflamm... more The myelin sheath and oligodendrocytes in the brain may be damaged by autoimmune-mediated inflammatory processes secondary to postinfectious demyelination or nutritional and vitamin deficiency. This article describes acute disseminated encephalomyelitis, acute hemorrhagic leukoencephalitis, acute necrotizing encephalopathy, and tumefactive demyelination as well as osmotic demyelination, Wernicke encephalopathy, Marchiafava-Bignami disease, and subacute combined degeneration of the spinal cord. Although some characteristic MR imaging features allow radiologists to suggest a diagnosis, these may overlap, and images should be interpreted in light of clinical symptoms and laboratory investigations.
Singapore medical journal, 2010
Bilateral vestibular schwannomas are the diagnostic features of neurofibromatosis type 2 (NF-2), ... more Bilateral vestibular schwannomas are the diagnostic features of neurofibromatosis type 2 (NF-2), and are the most common findings associated with the disorder. We report a three-year-old boy who presented with left facial nerve palsy and weight loss with bilateral large cerebellopontine (CP) angle masses that extended into the internal auditory canal on magnetic resonance imaging. The patient also had synchronous tumours in the lateral ventricle and intradural extramedullary spinal canal. The above findings were misinterpreted as NF-2 with bilateral vestibular schwannomas, ventricular meningioma and spinal schwannomas/meningiomas. However, histological examination of the spinal masses revealed a primitive neuroectodermal tumour. Although bilateral CP angle masses are characteristic of NF-2, the possibility of diffuse craniospinal malignancy should be considered in a very young child who presents with weight loss and extensive tumours.
Annals of the Academy of Medicine, Singapore, 2009
Radiologists may encounter bilaterally symmetrical abnormalities of the basal ganglia on magnetic... more Radiologists may encounter bilaterally symmetrical abnormalities of the basal ganglia on magnetic resonance imaging (MRI), typically in the context of diffuse systemic, toxic or metabolic diseases. A systematic approach and broad knowledge of pathology causing this uncommon group of conditions would be useful. This review uses illustrative images to highlight metabolic conditions, such as Leigh's syndrome, citrullinaemia, hypoglycaemia or carbon monoxide poisoning, as well as other causes of bilateral basal ganglia lesions such as osmotic myelinolysis, deep cerebral venous thrombosis and Creutzfeldt-Jakob disease. Careful assessment of radiological findings outside the basal ganglia, such as involvement of the cortex, white matter, thalamus and pons, together with clinical correlation, may be helpful in narrowing the differential diagnosis, and directing further radiological, biochemical or genetic investigations. Recent advances in MR technology have resulted in newer technique...
Annals of the Academy of Medicine, Singapore, 2012
Pediatric Radiology, 2009
Head trauma is the most common form of injury sustained in serious childhood trauma and remains o... more Head trauma is the most common form of injury sustained in serious childhood trauma and remains one of the top three causes of death despite improved road planning and safety laws. CT remains the first-line investigation for paediatric head trauma, although MRI may be more sensitive at picking up the full extent of injuries and may be useful for prognosis. Follow-up imaging should be tailored to answer the specific clinical question and to look for possible complications.
New England Journal of Medicine, 2009
A 50-year-old woman with hypertension had an acute pontine hemorrhage, as seen on computed tomogr... more A 50-year-old woman with hypertension had an acute pontine hemorrhage, as seen on computed tomography (Panel A, arrow), which resulted in quadriplegia. Thirty months later, she reported having difficulty reading because of oscillopsia. The physical examination revealed ...
Journal of Neurosurgery, 2008
There have been fewer than 60 cases of malignant teratocarcinosarcoma (TCS) described in the lite... more There have been fewer than 60 cases of malignant teratocarcinosarcoma (TCS) described in the literature, usually arising in the nose and paranasal sinuses. The authors report on a patient who presented with neurological symptoms caused by a frontal lobe TCS, and in whom widespread spinal tumor dissemination developed. In rare cases, TCSs can occur with a predominantly cranial and neurological presentation and spread to the spinal canal.
Journal of Medical Imaging and Radiation Oncology, 2012
1. Arbelaez A, Castillo M, Armao DM. Imaging features of intraventricular melanoma. AJNR Am J Neu... more 1. Arbelaez A, Castillo M, Armao DM. Imaging features of intraventricular melanoma. AJNR Am J Neuroradiol 1999;20:691-693 2. Enochs WS, Hyslop WB, Bennett HF, Brown RD. III, Koenig SH, Swartz HM. Sources of the increased longitudinal relaxation rates observed in melanotic melanoma. An in vitro study of synthetic melanins. Invest Radiol 1989;24:794-804 3. Gomori JM, Grossman RI, Shields JA, Augsburger JJ, Joseph PM, DeSimeone D. Choroidal melanomas: correlation NMR spectroscopy and MR imaging. Radiology 1986;158:443-445 4. Atlas SW, Grossman RI, Gomori JM, Guerry D, Hackney DB, Goldberg HI, Zimmerman RA, Bilaniuk LT. MR imaging of intracranial metastatic melanoma. J Comput Assist Tomogr 1987; 11:577-582 LETTERS LETTERS
comp.nus.edu.sg
This paper proposes a generative model approach to automatically annotate medical images to impro... more This paper proposes a generative model approach to automatically annotate medical images to improve the efficiency and effectiveness of image retrieval systems for teaching, research, and diagnosis. The generative model captures the probabilistic relationships among relevant classification tags, tentative lesion patterns, and selected input features. Operating on the imperfect segmentation results of input images, the probabilistic framework can effectively handle the inherent uncertainties in the images and insufficient information in the training data. Preliminary assessment in the ischemic stroke subtype classification shows that the proposed system is capable of generating the relevant tags for ischemic stroke brain images. The main benefit of this approach is its scalability; the method can be applied in large image databases as it requires only minimal manual labeling of the training data and does not demand high-precision segmentation of the images.
Radiographics, Nov 1, 2005
ABSTRACT A new method has been developed for multimedia enhancement of electronic teaching files ... more ABSTRACT A new method has been developed for multimedia enhancement of electronic teaching files created by using the standard protocols and formats offered by the Medical Imaging Resource Center (MIRC) project of the Radiological Society of North America. The typical MIRC electronic teaching file consists of static pages only; with the new method, audio and visual content may be added to the MIRC electronic teaching file so that the entire image interpretation process can be recorded for teaching purposes. With an efficient system for encoding the audiovisual record of on-screen manipulation of radiologic images, the multimedia teaching files generated are small enough to be transmitted via the Internet with acceptable resolution. Students may respond with the addition of new audio and visual content and thereby participate in a discussion about a particular case. MIRC electronic teaching files with multimedia enhancement have the potential to augment the effectiveness of diagnostic radiology teaching.
RadioGraphics, 2005
A new method has been developed for multimedia enhancement of electronic teaching files created b... more A new method has been developed for multimedia enhancement of electronic teaching files created by using the standard protocols and formats offered by the Medical Imaging Resource Center (MIRC) project of the Radiological Society of North America. The typical MIRC electronic teaching file consists of static pages only; with the new method, audio and visual content may be added to the MIRC electronic teaching file so that the entire image interpretation process can be recorded for teaching purposes. With an efficient system for encoding the audiovisual record of on-screen manipulation of radiologic images, the multimedia teaching files generated are small enough to be transmitted via the Internet with acceptable resolution. Students may respond with the addition of new audio and visual content and thereby participate in a discussion about a particular case. MIRC electronic teaching files with multimedia enhancement have the potential to augment the effectiveness of diagnostic radiology teaching.
Pediatric Neurology, 2007
Both the syndrome of mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (... more Both the syndrome of mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS syndrome) and Hashimoto's encephalopathy can present with nonspecific encephalopathy. Hashimoto's encephalopathy is an association of steroid-responsive encephalopathy with elevated thyroid peroxidase antibodies. Steroid-responsive encephalopathy, however, is not characteristic of the MELAS syndrome, which typically presents with stroke-like episodes and lactic acidosis in cerebrospinal fluid and blood. Here, a patient is described with goiter, recurrent encephalopathy and elevated thyroid peroxidase antibodies who apparently responded to steroid therapy; however, magnetic resonance imaging was atypical for Hashimoto's encephalopathy, and she was diagnosed with MELAS syndrome. This syndrome can present with apparent steroid-responsive encephalopathy and elevated thyroid peroxidase antibodies, mimicking Hashimoto's encephalopathy, and should be suspected if lactic acidosis is present and typical features are detected on magnetic resonance imaging.
Journal of Neurology, 2008
Clinical diagnosis of CJD remains important due to lack of access to a genetic or histopathologic... more Clinical diagnosis of CJD remains important due to lack of access to a genetic or histopathological diagnosis. Using current WHO criteria, diagnostic certainty can be increased from "possible" to "probable" CJD if periodic complexes are recorded on EEG. To study the correlation between patterns of MRI-DWI hyperintensity and typical EEG findings among patients with CJD. Demographics, clinical findings, MRI-DWI and EEG findings of CJD patients were retrospectively reviewed. A total of 14 patients ranging in age from 35 to 81 years were identified. All had dementia and cerebellar ataxia. Psychiatric manifestations were seen in 5 patients. Seven patients had both cortical and striatal DWI changes, five had isolated cortical DWI changes and two had isolated striatal DWI changes. All twelve patients with cortical DWI changes also had periodic EEG changes. In ten, periodic EEG was recorded within seven days of the DWI. The two patients with isolated striatal DWI changes did not develop periodic EEG complexes despite serial EEG recordings, 40 and 88 days from their respective DWI scans. Serial EEGs are not useful for patients with isolated striatal DWI hyperintensity but will increase diagnostic certainty from "possible" to probable" CJD for patients with cortical DWI hyperintensity.
Singapore medical journal
We describe a seven-year-old chinese girl with NF1 and unilateral MMS with multiple hyperintensit... more We describe a seven-year-old chinese girl with NF1 and unilateral MMS with multiple hyperintensities on T2-weighted magnetic resonance (MR) images. The ischaemic lesions in the ipsilateral white matter were hypointense on fluid attenuated inversion recovery (FLAIR) MR images, in contrast to the hyperintense "unidentified bright objects" (UBOs) of NF1. Neuroradiologists should be aware of associated MMS in NF1 patients, and distinguish the effects of ischaemia from UBOs, especially on FLAIR MR imaging.
Annals of the Academy of Medicine, Singapore
Introduction: Deep venous thrombosis (DVT) is thought to be less common in Asians than in the Cau... more Introduction: Deep venous thrombosis (DVT) is thought to be less common in Asians than in the Caucasian population. The incidence of asymptomatic DVT in high-risk groups in the Asian population has not been well studied. While DVT incidence among Caucasian stroke patients has been extensively studied and the need for prophylaxis established, the lack of data in Asian patients leaves physicians with no firm basis for adopting prophylactic protocols in the local population. Our aim was to prospectively establish the incidence of early DVT in immobilised stroke patients in a heterogenous Asian population. Materials and Methods: We screened 44 patients with significant hemiplegia from acute stroke. Doppler ultrasound, the currently accepted method of investigation for DVT, was used to study patients on admission and at 1 week post-stroke. While there was no standard prophylactic regime in use, none of the patients received heparin and only 2 were given compression stockings. Results: The incidence of DVT at 1 week was 2.4%. Review at 1 month detected another patient with DVT, bringing the overall incidence at 1 month to 4.8%. This is lower than in Caucasian populations, but is similar to another local study on a different group of high-risk patients. Conclusion: The low incidence of early DVT in hospitalised stroke patients of Asian ethnicity does not justify routine screening for this population. Further research to validate this should ideally include a comparison test for DVT as ultrasound may have inherently lower sensitivity in an asymptomatic population.
Neurology Asia
Advanced diffusion weighted (DW) MRI of the brain in the fatal outbreak of Nipah viral encephalit... more Advanced diffusion weighted (DW) MRI of the brain in the fatal outbreak of Nipah viral encephalitis among pig workers in Malaysia and Singapore revealed a pattern similar to ischaemic infarction caused by obstruction of small cerebral blood vessels. However, relapse and late-onset cases in Malaysia, and other outbreaks of Nipah virus in Bangladesh and the Hendra virus infection in Australia, showed a different MRI pattern of predominantly confluent cortical lesions. MRI was useful in characterizing the disease in acute infection, as well as detection of spine abnormalities and subclinical infection.
Annals of the Academy of Medicine, Singapore
The aim of this study was to review the clinical, computed tomography (CT) and magnetic resonance... more The aim of this study was to review the clinical, computed tomography (CT) and magnetic resonance imaging (MRI) diagnosis and the frequency of positive neuroimaging findings in patients with cerebral venous thrombosis (CVT) involving the superior sagittal sinus. A clinical and radiological database of patients with final diagnosis of CVT was compiled from the inpatient hospital information service of a tertiary neurological hospital over 5 years. CT and MRI studies in 22 patients were retrospectively examined for direct signs of venous sinus thrombosis and for complications of CVT. The diagnosis of CVT before and after CT and MRI was reviewed. Clinical diagnosis of possible CVT was suspected in only 1 patient. When the diagnosis was not suspected, CT diagnosis was difficult and there was a high false negative rate of 52.6%. MRI fared better, but the false negative rate was still 11%. Directs signs of venous sinus thrombosis such as the triangle sign, empty delta sign on CT and loss ...
Singapore medical journal, 2014
A 58-year-old Indian woman presented with asystole after an episode of haemetemesis, with a patie... more A 58-year-old Indian woman presented with asystole after an episode of haemetemesis, with a patient downtime of 20 mins. After initial resuscitation efforts, computed tomography of the brain, obtained to evaluate neurological injury, demonstrated evidence of severe hypoxic ischaemic brain injury. The imaging features of hypoxic ischaemic brain injury and the potential pitfalls with regard to image interpretation are herein discussed.
Neuroimaging clinics of North America, 2011
The myelin sheath and oligodendrocytes in the brain may be damaged by autoimmune-mediated inflamm... more The myelin sheath and oligodendrocytes in the brain may be damaged by autoimmune-mediated inflammatory processes secondary to postinfectious demyelination or nutritional and vitamin deficiency. This article describes acute disseminated encephalomyelitis, acute hemorrhagic leukoencephalitis, acute necrotizing encephalopathy, and tumefactive demyelination as well as osmotic demyelination, Wernicke encephalopathy, Marchiafava-Bignami disease, and subacute combined degeneration of the spinal cord. Although some characteristic MR imaging features allow radiologists to suggest a diagnosis, these may overlap, and images should be interpreted in light of clinical symptoms and laboratory investigations.
Singapore medical journal, 2010
Bilateral vestibular schwannomas are the diagnostic features of neurofibromatosis type 2 (NF-2), ... more Bilateral vestibular schwannomas are the diagnostic features of neurofibromatosis type 2 (NF-2), and are the most common findings associated with the disorder. We report a three-year-old boy who presented with left facial nerve palsy and weight loss with bilateral large cerebellopontine (CP) angle masses that extended into the internal auditory canal on magnetic resonance imaging. The patient also had synchronous tumours in the lateral ventricle and intradural extramedullary spinal canal. The above findings were misinterpreted as NF-2 with bilateral vestibular schwannomas, ventricular meningioma and spinal schwannomas/meningiomas. However, histological examination of the spinal masses revealed a primitive neuroectodermal tumour. Although bilateral CP angle masses are characteristic of NF-2, the possibility of diffuse craniospinal malignancy should be considered in a very young child who presents with weight loss and extensive tumours.
Annals of the Academy of Medicine, Singapore, 2009
Radiologists may encounter bilaterally symmetrical abnormalities of the basal ganglia on magnetic... more Radiologists may encounter bilaterally symmetrical abnormalities of the basal ganglia on magnetic resonance imaging (MRI), typically in the context of diffuse systemic, toxic or metabolic diseases. A systematic approach and broad knowledge of pathology causing this uncommon group of conditions would be useful. This review uses illustrative images to highlight metabolic conditions, such as Leigh's syndrome, citrullinaemia, hypoglycaemia or carbon monoxide poisoning, as well as other causes of bilateral basal ganglia lesions such as osmotic myelinolysis, deep cerebral venous thrombosis and Creutzfeldt-Jakob disease. Careful assessment of radiological findings outside the basal ganglia, such as involvement of the cortex, white matter, thalamus and pons, together with clinical correlation, may be helpful in narrowing the differential diagnosis, and directing further radiological, biochemical or genetic investigations. Recent advances in MR technology have resulted in newer technique...
Annals of the Academy of Medicine, Singapore, 2012
Pediatric Radiology, 2009
Head trauma is the most common form of injury sustained in serious childhood trauma and remains o... more Head trauma is the most common form of injury sustained in serious childhood trauma and remains one of the top three causes of death despite improved road planning and safety laws. CT remains the first-line investigation for paediatric head trauma, although MRI may be more sensitive at picking up the full extent of injuries and may be useful for prognosis. Follow-up imaging should be tailored to answer the specific clinical question and to look for possible complications.
New England Journal of Medicine, 2009
A 50-year-old woman with hypertension had an acute pontine hemorrhage, as seen on computed tomogr... more A 50-year-old woman with hypertension had an acute pontine hemorrhage, as seen on computed tomography (Panel A, arrow), which resulted in quadriplegia. Thirty months later, she reported having difficulty reading because of oscillopsia. The physical examination revealed ...
Journal of Neurosurgery, 2008
There have been fewer than 60 cases of malignant teratocarcinosarcoma (TCS) described in the lite... more There have been fewer than 60 cases of malignant teratocarcinosarcoma (TCS) described in the literature, usually arising in the nose and paranasal sinuses. The authors report on a patient who presented with neurological symptoms caused by a frontal lobe TCS, and in whom widespread spinal tumor dissemination developed. In rare cases, TCSs can occur with a predominantly cranial and neurological presentation and spread to the spinal canal.
Journal of Medical Imaging and Radiation Oncology, 2012
1. Arbelaez A, Castillo M, Armao DM. Imaging features of intraventricular melanoma. AJNR Am J Neu... more 1. Arbelaez A, Castillo M, Armao DM. Imaging features of intraventricular melanoma. AJNR Am J Neuroradiol 1999;20:691-693 2. Enochs WS, Hyslop WB, Bennett HF, Brown RD. III, Koenig SH, Swartz HM. Sources of the increased longitudinal relaxation rates observed in melanotic melanoma. An in vitro study of synthetic melanins. Invest Radiol 1989;24:794-804 3. Gomori JM, Grossman RI, Shields JA, Augsburger JJ, Joseph PM, DeSimeone D. Choroidal melanomas: correlation NMR spectroscopy and MR imaging. Radiology 1986;158:443-445 4. Atlas SW, Grossman RI, Gomori JM, Guerry D, Hackney DB, Goldberg HI, Zimmerman RA, Bilaniuk LT. MR imaging of intracranial metastatic melanoma. J Comput Assist Tomogr 1987; 11:577-582 LETTERS LETTERS