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Biomedical subjects

Hon-Man Liu

Publications and source records attributed to Hon-Man Liu.

29 records · Page 2Linked to original sources
PubMed2003

Diffuse capillary telangiectasia of the brain manifested as a slowly progressive course.

Brain capillary telangiectasia (BCT) are usually small, solitary, benign in clinical manifestation, or found incidentally at autopsy. However, diffuse BCT are rarely reported. A 39-year-old woman had the first generalized seizure 10 years previously. Thereafter, she had sustained progressive spastic paraparesis and blurred vision. Computed tomography (CT) showed diffuse brain atrophy with numerous calcified spots. Contrast T1-weighted magnetic resonance images showed diffuse faintly enhancing lesions with stippled appearance in the whole brain. Cerebral angiography revealed multiple small nets of dilated capillaries and Xenon CT showed diffuse low cerebral blood flow in the resting and good cerebral reserve capacity in the acetazolamide challenge test. Therefore, diffuse BCT was diagnosed clinically. Although BCT are not rare, diffuse BCT with slowly progressive neurological symptoms had never been reported before. It causes global cerebral ischemia that lead to brain atrophy and a degenerative course.

Adult↗
PubMed2003

The hemodynamic effects of internal carotid artery stenting: a study with color-coded duplex sonography.

BACKGROUND: Stenting has been used as an alternative treatment for patients with internal carotid artery (ICA) stenosis. Color-coded duplex sonography (CDS) is able to measure not only the prestenting stenosis but also the poststenting hemodynamic changes. The purpose of this study was to quantify, using CDS, the hemodynamic changes after ICA stenting. METHODS: Both symptomatic and asymptomatic patients were included in this study. The degree of ICA stenosis before stenting was required to be more than 50%. Thirty-two treated ICAs were included to compare the prestenting and poststenting CDS findings, including the diameter and cross-sectional area of the lumen, the flow peak systolic and end-diastolic velocities, the resistivity index and the amount of flow in bilateral extracranial carotid and vertebral arteries. RESULTS: After stenting, the turbulent flow pattern in the stenotic ICA recovered to laminar flow, and the reversed ophthalmic flow direction normalized. Of the CDS parameters applied to evaluate the effect of stenting on ICA stenosis, the diameter, residual area, peak systolic velocity, diastolic velocity and the ration of systolic flow velocity ratio in the ICA to that in the common carotid artery (CCA) were altered significantly. The mean area and residual area of these stenotic ICAs showed increases of 24% (p = 0.005) and 84% (p = 0.001) after ICA stenting, respectively. The mean peak systolic flow velocity significantly decreased by 71%. The mean diastolic flow velocity also significantly decreased (by 77%). Both the systolic and diastolic velocities of the ipsilateral CCA significantly increased after stenting. The amount of flow in the contralateral ICA decreased significantly after stenting. The change in the amount of flow in the vertebral arteries after ICA stenting was insignificant. CONCLUSIONS: The results of this CDS study clearly demonstrated the hemodynamic changes after ICA stenting. The carotid stenting significantly changed the ICA flow pattern, diameter, residual area, peak systolic velocity and ICA to CCA velocity ratio.

Aged↗
PubMed2002

The efficacy of papaverine administration by different routes for the treatment of experimental acute cerebral vasospasm.

OBJECTIVE: To compare the effect of papaverine (PPV) by different routes of administration for the treatment of experimental acute cerebral vasospasm. METHODS: A rabbit model of acute cerebral vasospasm induced by autologous blood injected into the basilar and prepontine cistern was used. The PPV (2mg/kg) was injected either by an intravenous (IV), intra-arterial (IA), intra-cisternal (IC), or combination of intra-arterial and intra-cisternal (IA+IC) routes. Basilar artery diameters were measured before and after vasospasm was induced and after PPV treatment. RESULTS: Induction of vasospasm reduced basilar artery diameters by more than 50% in all animals. Compared to artery diameters before vasospasm, diameters after PPV treatment via the IV route were only reduced by 0.5+/-4.7%. Other reductions in the diameter included 29.1+/-10.4%, about 1.8+/-3.1%, and about 26.7+/-8.4% in the IA, IC, and IA+IC groups, respectively. However, IA administration of PPV caused obvious side effects. CONCLUSION: Intra-arterial application of the PPV was the most effective way to treat vasospasm in this study. The efficacy of IC route in our study did not confirm the results of prior study. The possibility of side effects of PPV via the IA route should be considered before clinical application.

Acute Disease↗
PubMed2002

Subthalamotomy for advanced Parkinson disease.

OBJECT: The aim of this study was to determine if subthalamotomy is effective in treating advanced Parkinson disease (PD). METHODS: The authors performed microelectrode mapping-guided stereotactic surgery on the subthalamic nucleus in eight patients with PD. Lesioning was performed using radiofrequency heat coagulation and confirmed with magnetic resonance imaging. Three patients who underwent unilateral and four with bilateral subthalamotomy were evaluated for up to 18 months according to the Unified PD Rating Scale (UPDRS). One patient who underwent unilateral subthalamotomy died 6 months postsurgery. At 3 months into the "off" period after surgery, there were significant improvements in contralateral bradykinesia (p < 0.0002), rigidity (p < 0.0001), tremor (p < 0.01), axial motor features (p < 0.02), gait (p < 0.03), postural stability (p < 0.03), total UPDRS scores (p < 0.03), and Schwab and England scores (p < 0.04). The benefits were sustained at 6, 12, and 18 months, except for the improvement in tremor. At 12 months into the "on" period, significant benefits were present for motor fluctuation (p < 0.04), on dyskinesia (p < 0.006), off duration (p < 0.05), total UPDRS score (p < 0.02), and contralateral tremor (p < 0.05). Benefits for motor fluctuation, off duration, and off-period tremor were lost after the 18-month follow-up period. The levodopa requirement was reduced by 66% for the unilateral and 38% for the bilaterally treated group. Bilateral subthalamotomy offered more benefits than did unilateral surgery for various parkinsonian features in both the on and off periods. Three patients suffered hemiballismus, two recovered spontaneously, and one died of aspiration pneumonia after discontinuation of levodopa. CONCLUSIONS: These findings indicate that subthalamotomy can ameliorate the cardinal symptoms of PD, reduce the dosage of levodopa, diminish complications of the drug therapy, and improve the quality of life.

Aged↗
PubMedDate not supplied

Diffusion-weighted images in children with meningoencephalitis.

PURPOSE: The objective of the study was to evaluate the maps of apparent diffusion coefficients (ADCs) and diffusion-weighted (DW) images in demonstrating meningoencephalitic lesions in children. MATERIALS AND METHODS: Between May 1998 and May 2000, 18 infants and children (4.5-190 months old) suffering from meningoencephalitis were included in the study. The diagnoses were bacterial meningoencephalitis in 8 and aseptic or viral in 10 patients. All 18 patients had brain MRI examinations. In the axial plane, three pulse sequences were performed on all patients: (1) FSE T2W images; (2) fast FLAIR images; (3) single-shot echoplanar DW images were acquired. Another 18 patients from the control group also received DW image examination. ADCs were computed for all regions on each DW image. RESULTS: The absolute values of CNRs of lesions on T2W (7.27+/-5.51), FLAIR (5.56+/-5.03) and DW (13.36+/-16.64) images were significantly greater than those on ADC maps (0.42+/-0.30) in the study group of patients (P<.01). In addition, absolute CNRs on DW images were significantly greater than on T2W and FLAIR images (P<.01). However, lesions on ADC maps in the study group have significantly greater CNRs than in the control group (0.13+/-0.12) (P<.01). CNRs on initial DW images from patients with atrophy or swelling of meningoencephalitic lesions were significantly different from the CNRs of those patients without significant changes in meningoencephalitic lesions (P=.02<.05). CONCLUSION: The DW image is a sensitive tool for detecting meningoencephalitic lesions and is better than FSE T2W and fast FLAIR images in CNRs. Diffusion MR techniques provides new ways to possibly predict the outcome of intracranial infectious diseases in children.

Brain Mapping↗
PubMedDate not supplied

Intraductal papillary carcinoma of bilateral breasts: a case report.

We report a 59-year-old woman presenting with a 2-month history of occasional bloody discharge from her right nipple and a palpable right breast mass on self-examination. The mammography revealed heterogeneously dense fibroglandular stromas of bilateral breasts, a lobulated mass in her right breast associated with faint pleomorphic microcalcifications, and, in addition, very faint focal granular microcalcifications in the left breast. Breast ultrasound revealed a lobulated and heterogeneous hypoechoic tumor with irregular margins at the right breast and a well-circumscribed tumor with heterogeneous echotexture at the left breast.

Breast Neoplasms↗
PubMedDate not supplied

Comparison of contrast-enhanced magnetization transfer imaging and contrast-enhanced fat saturation T1-weighted imaging in nasopharyngeal carcinoma.

OBJECTIVE: The objective of this study was to evaluate the efficacy of contrast-enhanced magnetization transfer (CEMT) imaging in the study of nasopharyngeal carcinoma (NPC). METHODS: The contrast-to-noise ratio (CNR) of CEMT images was compared with the CNR of contrast-enhanced fat-saturation (CEFS) T1-weighted images in locoregional tumors and adenopathies of 50 patients with pathologically proven NPC. RESULTS: The CEMT images showed higher CNRs than CEFS images of local nasopharyngeal regions. The mean CNRs of the precontrast T1-weighted, CEFS, and CEMT images were 4.9, 15.4, and 21.2, respectively. There was a statistically significant difference (p < 0.01) in the CNRs of CEFS and CEMT images. In considering images of nodal metastasis, the mean values in these three groups were 0.7, 16.8, and 19.7, respectively, with the difference (p < 0.05) between CEFS and CEMT being statistically significant. CONCLUSIONS: The CEMT image with a larger CNR is superior to the CEFS image in detecting locoregional NPC. CEMT can be useful in imaging patients with possible small tumors and local recurrences.

Adolescent↗
PubMedDate not supplied

Moyamoya syndrome with inherited proteins C and S deficiency: report of one case.

Moyamoya disease (MMD) is a vascular abnormality characterized by progressive narrowing of the internal carotid, middle, anterior and posterior cerebral arteries and the development of basal collaterals forming the classic angiographic appearance-moyamoya. Protein C (PC) and its cofactor, protein S (PS), which are vitamin-K dependent, act as inhibitors of coagulation cascade by inactivating factor Va and factor VIIIa and facilitating thrombolysis. Deficiencies of these proteins leading to a prothrombotic state increase the risk of ischemic cerebrovascular accident. Herein we report a 3-year-old girl, who had an acute onset of right-side hemiparesis during an episode of herpetic gingivostomatitis. She was noted to have moyamoya syndrome in the angiographic examination and was later proved to have inherited deficiencies of both PC and PS. She received warfarin medical treatment and then bilateral encephalo-duro-arterio-synangiosis (EDAS) and encephalo-myo-synangiosis (EMS) due to neurological deterioration and is now under the use of low molecular weight heparin for preventing further ischemic stroke. The motor deterioration improved after medical and surgical intervention. We conclude that coagulopathy like PC or PS deficiency should be considered in children presenting with moyamoya syndrome.

Child, Preschool↗