PubMed Health⌕ Search

Biomedical subjects

Y S Soo

Publications and source records attributed to Y S Soo.

At least 19 recordsLinked to original sources
PubMed1998

Neuroradiological features of six kindreds with MELAS tRNA(Leu) A2343G point mutation: implications for pathogenesis.

OBJECTIVE: To determine the neuroradiological abnormalities associated with subjects carrying the mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes (MELAS) tRNA(Leu)(UUR) A3243G point mutation METHODS: Mitochondrial genetic analysis was performed on 24 subjects from six kindreds with the MELAS tRNA(Leu)(UUR) A3243G point mutation. Cerebral CT and MRI were performed on 24 patients and 15 patients respectively. Previous neuroradiological investigations including cerebral CT from four deceased members of the families were also reviewed. Histological examination of postmortem specimens of two patients within the kindreds was performed. RESULTS: The commonest radiological finding was basal ganglia calcification. Other abnormalities included focal lesions and cerebellar and cerebral atrophy. Basal ganglia calcification was progressive, symmetric, and asymptomatic. Histologically, basal ganglia calcification in one patient was found to be in the pericapillary regions of the globus pallidus, with no neuronal involvement. Focal lesions most commonly involved the grey matter of the parietal and occipital lobes and cerebellum. Histopathological examination suggested that these were due to cellular rather than vascular dysfunction. Enlargement of the fourth ventricle was the first sign of cerebellar atrophy. Cerebral and cerebellar atrophy were only present with severe disease. CONCLUSIONS: These radiological findings, when considered in the context of the clinical and pathological findings, seem to reflect two major disease processes: an intermittent abrupt loss of function associated with cell injury from which there is at least partial recovery and a slowly progressive degenerative process causing basal ganglia calcification, and cerebral and cerebellar atrophy. The clinical and radiological features resulting from these processes are distinctive and provide insight into the consequences of mitochondrial dysfunction on the brain.

Adolescent↗
PubMed1997

Clonic perseveration following thalamofrontal disconnection: a distinctive movement disorder.

We describe four patients who developed asymmetrical, rhythmic, stereotyped, and repetitive movements of the upper and lower limbs hours to days after infarction that involved the thalamus and/or basal ganglia. The movements appeared to occur spontaneously and were initially labeled as focal motor seizures, ballism, or tremor; they could however, be induced by passive movement of the limbs. The movements most commonly observed were scratching or rubbing movements of the hands that were of such persistence as to cause trauma to the skin; in the lower limbs, the heel was run up and down the bed sheet, often until it bled. The movements were part of a syndrome characterised initially by a reduced level of consciousness and followed by aspontaneity, usually with mutism and frontal release signs. One patient who had relatively preserved cognition and language repeated words or phrases again and again when encouraged to speak, but had no difficulty changing responses appropriately to different cues. In drawing, he overwrote each figure but could change the figure on command. The distinctive movement disorder in these patients was due to clonic perseveration. We suggest that clonic perseveration results from disconnection of prefrontal cortico-basal ganglia-thalamo-cortical loops that are important for the termination of motor plans. Clonic perseveration should be recognised as a movement disorder following thalamic lesions.

Aged↗
PubMed1996

Arachnoiditis ossificans of the cauda equina demonstrated on computed tomography scanogram. A case report.

STUDY DESIGN: This case report illustrates a patient with arachnoiditis ossificans of the cauda equina of sufficient severity to be demonstrable on a computed tomography scout view. OBJECTIVES: The diagnosis of extensive arachnoiditis ossificans by computed tomography does not necessitate surgical intervention. The authors patient had only mild, chronic symptoms when treated expectantly. SUMMARY OF BACKGROUND DATA: The value of axial computed tomography in visualizing and characterizing the lesions of arachnoiditis ossificans has been well documented. Arachnoiditis ossificans involving the cauda equina is uncommon. To the authors' knowledge, this report represents the first case of arachnoiditis ossificans of the cauda equina in which the arachnoid calcifications were of sufficient density to be obvious on a computed tomography scan. METHODS: The patient was reviewed by a neurologist for paraesthesia in his right foot, occasional backaches, and urinary frequency. Physical examination revealed only a mild loss of lumber lordosis and an area of hypoesthesia in the right foot. He then was investigated with computed tomography, which showed extensive arachnoiditis ossificans. Because his symptoms were mild, surgery was not contemplated. RESULTS: The patient's symptoms remained minimal despite being treated conservatively. CONCLUSIONS: The value of computed tomography in delineating the lesions of arachnoiditis ossificans and the outcome of surgery for resection of its compressive osseous plaques have been well described. Despite extensive arachnoid calcification caused by arachnoiditis ossificans involving the cauda equina that was visible on a computed tomography scan, this patient continued to have only low-grade symptoms when treated conservatively.

Aged↗
PubMed1996

Intraventricular neurocytoma.

Intraventricular neurocytoma is a rare cerebral tumour which is usually associated with a good prognosis. It has imaging features which help differentiate it from other cerebral tumours. We report three cases including the first to originate from the pineal gland. The report emphasizes the radiological appearance and reviews the literature.

Adolescent↗
PubMed1996

A review of the radiological features of intracranial meningiomas.

To evaluate the role of radiological imaging of meningiomas in confirming the diagnosis and as a neuroanatomical aid to surgical planning, 115 patients with surgically excised meningiomas between 1990 and 1993 were studied. Computed tomography (CT), magnetic resonance imaging (MRI) (on a 0.5 T unit) and angiography were reviewed, and compared with histopathology (when available). Seventy-eight CT, 89 MRI and 85 angiographic studies were reviewed, and correlated with histopathology in 67 cases. In 48 cases, the surgical specimens could not be pathologically classified. The most common lesion sites were the cerebral convexities, falx and sphenoidal ridges. True demarcation of cleavage planes was seen on 73% of MRI and 10% of CT studies. Computed tomography showed hyperostosis in 27% and MRI in 7% of studies. Tumours enhanced strongly with contrast in 98% of CT scans. On MRI there were variable signal intensities on different sequences, and no correlation between signal intensities and histological subtype was found. Oedema was present in 59% of CT and 66% of MRI studies, and was most pronounced in lesions > 3 cm in diameter. Tumour calcification was seen in 62% of CT and 8% of MRI studies. Vascular abnormalities were seen on 65% of MRI, 21% of CT and 84% of angiogram studies. Angiographic tumour vascularity did not correlate with histologic subtype. All three imaging modalities have management roles: CT for bony changes and calcification, MRI for multiplanar and vessel anatomy imaging, and angiography for vessel delineation and embolization if required.

Aged↗
PubMed1995

Caries experience in rural Victorian adolescents.

An oral health status survey was conducted on 818 adolescents aged 12 to 16 years in a non-fluoridated area in rural Victoria. The prevalence and severity of dental caries experience was found to increase with age. The occlusal surface was the predominant surface affected by dental caries for all age groups. Filled surfaces represented the largest component of the DMFS index and were responsible for the increasing dental caries experience with age. Fewer fissure sealants were present with increasing age and second molars were sealed less often than the first molars. Although no difference was evident in the total caries experience between those with and without access to public dental services, a statistical difference was found to exist in unmet need between these two groups. Untreated caries levels were significantly higher in health card holders. The provision of preventive and dental treatment services to this group should be a priority in the future.

Adolescent↗
PubMed1994

Imaging of thoracic aortic dissection.

Acute thoracic aortic dissection has a high mortality if untreated, so the diagnosis must be rapidly made if mortality is to be lowered significantly. Multiple imaging techniques are often used. This retrospective study from 1988 to 1993 assesses the usefulness in diagnosis of chest X-rays, computed tomography (CT) scanning, aortography, magnetic resonance imaging (MRI), trans-thoracic (TTE) and trans-oesophageal (TOE) echocardiography. Forty-two patients with a final clinical diagnosis of dissection were studied. The diagnosis was confirmed in 16 (13 at surgery and three at autopsy). Three died with dissection given as the only cause for death. Chest X-ray abnormalities were seen in all 19 patients with surgery or death from dissection, with a widened mediastinum and/or dilated aorta being present in 17. In the group of 16 patients with surgery or autopsy proof, CT scans found dissections in 9 of 12 patients studied and correctly classified the type in only five. Aortography was performed in five, with accurate depiction of dissection and type in all. TTE found dissections in three of eight patients imaged by this method. MRI and TOE were performed each on two patients, with accurate depiction of dissection and type in each. Because of the relatively low sensitivity of CT scanning in defining aortic dissections Westmead Hospital is currently assessing the use of TOE as the prime imaging modality prior to surgical intervention.

Acute Disease↗
PubMed1994

Delayed cerebral radiation necrosis.

The clinical features and long-term outcome of seven patients with delayed cerebral radiation necrosis (DCRN) are described. Radiotherapy had been given for pituitary tumour (1), astrocytoma (2), pinealoma (2), craniopharyngioma (1) and parotid carcinoma (1). The mean latency to onset of the first neurological symptoms was 22 months (range 6-40 months), and mean duration of follow-up was 86 months (range 60-126). Three patients died at a mean of 84 months after radiotherapy (range 62-98). A fourth patient probably died from metastatic disease. Three patients remain alive, albeit severely disabled, after 5-10 years. The illness typically ran a stepwise course, with fits and stroke-like episodes occurring against a background of progressive dementia and somnolence. CT and MRI scans showed progressive ventricular dilatation associated with cerebral atrophy and diffuse or focal changes in the white matter. Four patients had had two or more neurosurgical procedures after the radiotherapy. In only one of the seven patients was the diagnosis made at presentation. DCRN produces a distinctive clinical picture, yet remains a poorly recognized complication of cranial irradiation.

Adolescent↗
PubMed1993

Acute intracerebral haematomas: assessment for possible underlying cause with MRI scanning.

Forty-seven patients presenting with acute intracerebral haematomas between 1989 and 1992 were retrospectively examined to assess the role of Magnetic Resonance Imaging (MRI) in identifying any underlying lesion. None had any prior known intracerebral pathology. Magnetic resonance imaging scans were done on a 0.5 T unit. Ten patients with an average age of 35 years had angiographically occult vascular malformations (AOVM) found by MRI (one with biopsy confirmation). One of three cases of glioma, three of three cases with secondary tumour, one case of superior sagittal sinus thrombosis with haemorrhagic infarction, one of two cases of venous angioma and one case of arteriovenous malformation were detected by MRI. Progress computed tomography scans discovered two cases of glioma and angiography found a venous angioma and an arterial aneurysm, all undetected by MRI. It is concluded that MRI scanning is helpful in detecting underlying AOVM as a cause of intracerebral haemorrhage but its role in imaging haemorrhagic tumours remains unclear.

Acute Disease↗
PubMed1992

Comparison of duplex ultrasound with angiography in assessment of carotid bifurcation disease.

This is a study comparing duplex ultrasound against the "gold standard" of angiography in assessing atherosclerotic disease of the carotid bifurcation, prior to prospective endarterectomy surgery. Thirty-nine patients were studied with both sonography and angiography studies being performed within one month of each other. Plaques were described by sonography as being "smooth" or "irregular" in surface and "homogeneous" or "heterogeneous" in composition. Ultrasound showed an overall 92% sensitivity, against the standard of angiography, in its ability to assess the degree of internal carotid stenosis. There was only a 63% sensitivity with the common carotid arteries and only a 65% sensitivity with the external carotid arteries. Ultrasound did not show a high accuracy in detecting plaque ulceration when compared against angio-graphy.

Adult↗
PubMed1992

Ectasia and fenestration of the anterior cerebral artery associated with persistent trigeminal artery: case report.

Multiple vascular anomalies in a 22-year-old patient who had signs and symptoms of vestibulocochlear dysfunction are reported. Angiography revealed a fenestration of the proximal segment of the left anterior cerebral artery, an ectasia of the left anterior and posterior cerebral arteries, and a persistence of the right trigeminal artery. The rarity of the association is documented, and the clinical significance is discussed.

Adult↗
PubMed1991

Duplication of the vertebro-basilar system.

During the examination of 75 fixed brains and 2086 vertebral angiograms we encountered two cases of fenestration of the vertebral artery and two cases of partial duplication of the basilar artery. In the first case, an 81 year old male, there was fenestration, of the basilar artery at the union of the two vertebral arteries. The fenestration was 9mm long with no associated vascular disease. The other partial duplication of the basilar artery was observed in the upper portion of the artery in a 54 year old male patient investigated angiographically for subarachnoid haemorrhage. The fenestration of the third case was demonstrated in the intracranial part of the right vertebral artery of a 50 year old female patient during digital subtraction angiography for subarachnoid haemorrhage. In the fourth case, the fenestration was found angiographically at the atlanto-axial level in the extracranial portion of the left vertebral artery in a 37 year old female patient with subarachnoid haemorrhage from an arteriovenous malformation in the left cerebral hemisphere. The embryonic, histological and radiological implications of the duplication are discussed.

Adult↗
PubMed1991

Cystic cerebellar schwannoma: case report.

We report a case of cerebellar schwannoma in a 64-year-old woman. The tumor was defined on computed tomographic and magnetic resonance imaging scans and confirmed on surgery. The solid part of the tumor appeared to be derived from the inferior vermis of the cerebellum, the cystic part extending toward the medulla oblongata and the foramen magnum. The problem of preoperative diagnosis based on magnetic resonance imaging findings is discussed.

Cerebellar Neoplasms↗