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Biomedical subjects

D C Suh

Publications and source records attributed to D C Suh.

At least 37 records · Page 2Linked to original sources
PubMed2000

Change of spontaneous reaction of glue and lipiodol mixture during embolization after the addition of tungsten powder: in vitro study.

BACKGROUND AND PURPOSE: We have noted that glue-Lipiodol mixtures harden prematurely in the catheter during embolization of brain arteriovenous malformations. However, we observed that hardening of this embolic material does not occur when tungsten powder is added to the glue mixture. In order to clarify the effect of tungsten powder on the glue mixture, we evaluated the reaction time and hardness of the glue mixture in vitro after the addition of tungsten powder. We also measured the pH of the tungsten solution. METHODS: Six lots of Lipiodol and three lots of Histoacryl Blue were mixed in a 5-cc bottle with a 50% to 25% glue concentration (glue:Lipiodol = 1:1 to 1:3) and this mixture was observed for 2 weeks. The hardness of the polymerized glue mixture was categorized as liquid, gel, semi-solid, or solid. Various series of experiments were performed after the addition of tungsten powder (0.2 g) and blood (a drop) into the glue mixture. We also separately mixed tungsten and tantalum powder in tubes, each with 5 mL of distilled water, and then measured the pH of these three times. The mixed amounts of tungsten and tantalum ranged from 0.1 to 0.5 mg. RESULTS: In a 50% glue concentration, the glue mixture turned into a solid cast within 48 hours. In a 25% concentration, the glue mixture turned into gel within 24 hours. The casts became solid in the 50% and gelled in the 25% concentration, and solid or gel in 28% and 33% glue mixture concentrations. The addition of tungsten powder to 50% and 25% glue mixture concentrations caused the glue mixtures to remain in a liquid state for 2 weeks regardless of the Lipiodol products used. Measurement of acidity achieved using a pH meter in 5 cc of distilled water with tungsten powder (0.1 to 0.5 g) revealed a change of pH from 3.5 to 2.6 according to the amount of tungsten added. Tantalum revealed weak acidity, with a pH range from 6.4 to 5.7. The addition of blood immediately caused the mixture to become solid in 50% and semi-solid in 25% glue concentrations. CONCLUSION: The reaction time of the glue mixture differed according to the lot number of the Lipiodol. The addition of tungsten powder appeared to prevent premature cast formation by decreasing the pH with a mechanism similar to that of adding acetic acid.

Chemical Phenomena↗
PubMed2000

Castleman's disease in the retropharyngeal space: CT and MR imaging findings.

We report CT and MR imaging findings in a case of Castleman's disease involving the retropharyngeal space in a middle-aged woman. On CT scans, a well-marginated, homogeneous, and densely enhancing mass was detected in the right retropharyngeal space. The mass was isointense to the muscle on T1-weighted MR images, hyperintense to the muscle on T2-weighted MR images, and showed homogeneous, strong enhancement on contrast-enhanced T1-weighted MR images. The linear hypointense signal in an arborizing pattern was observed within the mass on all pulse sequences.

Adult↗
PubMed2000

Localized proton MR spectroscopy of the allocortex and isocortex in healthy children.

BACKGROUND AND PURPOSE: The human allocortex is different from the isocortex in neuroglial cytoarchitecture. The purpose of this study was to compare metabolic data of the allocortex with those of the isocortex by using localized proton MR spectroscopy. METHODS: Short-TE stimulated-echo acquisition mode proton MR spectroscopy (TR/TE = 3000/30) was applied to the allocortex of the temporal lobe and isocortex of the parietal or frontal lobe in 30 healthy children (19 boys and 11 girls, 3-14 years old). Peak intensities of N-acetylaspartate (NAA), choline-containing compounds (Cho), and myo-inositol (mI) relative to creatine and phosphocreatine (Cr) were calculated. Metabolic data from the investigated regions were compared. RESULTS: NAA/Cr was significantly lower in the allocortex than in the isocortex of the parietal or frontal lobe: 1.05 +/- 0.12 (n = 33) vs. 1.36 +/- 0.10 (n = 28) or 1.32 +/- 0.10 (n = 12), respectively. Cho/Cr and mI/Cr were significantly higher in the allocortex than in the isocortex: 0.84 +/- 0.11 vs. 0.56 +/- 0.06 or 0.75 +/- 0.10; 0.78 +/- 0.15 vs. 0.54 +/- 0.08 or 0.66 +/- 0.09, respectively. In the isocortex, NAA/Cr was not different but Cho/Cr and mI/Cr were significantly higher in the frontal cortex than in the parietal cortex. CONCLUSION: Clear metabolic differences were observed between the allocortex and isocortex.

Adolescent↗
PubMed1999

Factors contributing to trends in prescription drug expenditures.

Between 1970 and 1995, national prescription drug expenditures and Medicaid drug expenditures increased proportionately less than did total health care expenditures and total Medicaid expenditures, respectively, although they increased to a greater extent than did expenditures in other sectors of the economy. General inflation, which cannot be controlled by health care policy, has been the major factor contributing to the growth in national prescription drug expenditures. Other contributors were population growth, increases in per capita prescription use, increases in per-prescription intensity (ie, real drug expenditures), and the fact that prescription drug prices exceeded general inflation. Medicaid drug expenditures have increased mainly because of growth in the number of drug recipients, increases in prescription drug prices, and economy-wide inflation.

Data Collection↗
PubMed1999

Trends of generic substitution in community pharmacies.

The purpose of this study is to measure the rate of genetic drug substitution by pharmacists, and factors influencing generic substitution, such as the extent of drugs listed on the formulary as well as physicians' and patients' acceptance rate of generic substitutes. A total of 9,328 prescription orders were retrospectively reviewed from 94 pharmacies which were selected at random. The substitution rate by pharmacists, which is the rate using the number of prescriptions eligible for substitution as the denominator, has risen from 47% in 1979 to 96% in 1997; double the rate over the past 20 years. The net substitution rate, which uses all prescriptions as the denominator, was 30% in 1997; over 4 times greater than the rate in 1979. Physicians wrote most prescriptions (86%) using the brand name of the drug, which has been the trend for the past 20 years. Of the prescriptions ordered by brand name, 47% were substitutable according to the New Jersey formulary. Of these prescriptions, prescribers allowed generic substitution 77% of the time. Out of these prescriptions, 97% of patients agreed to use a generic substitute if the physician approved of substitution. Generic substitution rates have increased, probably due to greater acceptance of generics by physicians and pharmacists as well as encouragement from external sources such as third party payers. Health care professionals, third parties, and patients all have an important role to play in order to increase the use of generics, and therefore reduce drug expenditures.

Drug Prescriptions↗
PubMed1999

Transluminal angioplasty for middle cerebral artery stenosis in patients with acute ischemic stroke.

BACKGROUND AND PURPOSE: Precutaneous transluminal angioplasty (PTA) is currently performed to treat supraaortic atherosclerotic lesions. Our purpose was to evaluate the safety and efficacy of PTA for middle cerebral artery (MCA) stenosis in patients with acute ischemic stroke. METHODS: We performed PTA with the use of a microballoon (2-2.5 mm in diameter and 10-13 mm in length) in 10 consecutive patients (mean age, 48 years) who met the following criteria: high-grade M1 stenosis (> 70%) and mild neurologic deficits (NIH stroke scale < 4) and/or recurrent transient ischemic attacks (TIAs) resistant to anticoagulation, or a large area of hypoperfusion in the MCA territory on brain perfusion SPECT scans. During follow-up, we administered antiplatelet agents and evaluated the status of restenosis by angiography (n = 2), brain perfusion SPECT (n = 4), and/or transcranial Doppler sonography (TCD) (n = 7). RESULTS: Stenotic arteries were successfully dilated in nine of 10 patients. Angioplasty failed in one patient because the balloon could not pass through the tortuous cavernous internal carotid artery. None of the patients experienced either peri- or postangioplasty complications. Residual stenosis was less than 50%, and clinical improvement, including elimination of TIAs in four patients who had suffered resistant TIAs, was observed in all patients; improvement of the cerebral perfusion was also noted in two patients with a large hypoperfusion area in the MCA territory. The average follow-up period was 11 months (range, 2 to 36 months). None experienced recurrent stroke during the follow-up period. TCD revealed decreased flow velocity of the MCA after angioplasty in seven patients. CONCLUSION: PTA of the proximal portion of the MCA seems to be a safe and effective therapeutic technique for the prevention of secondary ischemic stroke.

Acute Disease↗
PubMed1999

Multifocal meningioangiomatosis: a report of two cases.

We report the CT and MR findings in two patients with multifocal meningioangiomatosis, neither of whom had a family history or stigmata of neurofibromatosis. All lesions were located in the cortical and subcortical areas and had round dense calcifications with eccentric cysts. The masses were associated with surrounding edema and gliosis.

Angiomatosis↗
PubMed1999

Focal lesion in the splenium of the corpus callosum in epileptic patients: antiepileptic drug toxicity?

BACKGROUND AND PURPOSE: Discrete focal lesions in the splenium of the corpus callosum on MR images in epileptic patients have received little attention in the literature. Our purpose was to describe these lesions, which may be related to the toxicity of antiepileptic drugs (AEDs), and to discuss the possible mechanisms of their development. METHODS: We examined six patients with epilepsy whose brain MR imaging findings showed a discrete focal nonhemorrhagic lesion in the splenium of the corpus callosum. The medical records and MR images were reviewed retrospectively with respect to the patients' clinical history, medication, and laboratory findings to determine the etiology of the lesion. RESULTS: In all six patients MR imaging showed a focal lesion in the splenium of the corpus callosum, which was ovoid in shape and 15 to 19 mm in size. In the three patients who received contrast material, there was no enhancement of the lesion. Four of six patients had a history of medication with dilantin, in two of whom the level of serum dilantin was found to be elevated (22.3 micrograms/mL and 70.4 micrograms/mL, respectively). Vigabatrin was administered in three patients, one of whom took dilantin together with vigabatrin. In two patients, the focal lesion in the corpus callosum disappeared on follow-up MR images after withdrawal of dilantin and/or vigabatrin. CONCLUSION: A discrete, focal, ovoid, nonhemorrhagic lesion in the splenium of the corpus callosum may be seen on brain MR images of patients with epilepsy. The lesion is considered to be reversible demyelination related to AEDs toxicity.

Adult↗
PubMed1999

Location of the primary motor cortex in schizencephaly.

BACKGROUND AND PURPOSE: Functional reorganization of the brain can result from congenital brain disorders as well as from brain infarction. The purpose of our study was to use functional MR imaging to determine whether reorganization of brain function occurs in patients with schizencephaly. METHODS: Four patients with schizencephaly (three right-handed, one ambidextrous) presented with seizures. Associated lesions included agenesis of the corpus callosum (n = 1) and absence of the septum pellucidum (n = 1). Functional MR imaging was performed in each patient using a single-section fast low-angle shot (FLASH) blood oxygen level-dependent (BOLD) technique at 1.5 T in a standard head coil. The motor cortex was initially identified on an axial T1-weighted anatomic image. Thirty consecutive images were obtained during a motor task consisting of repetitive finger-to-thumb opposition. The percentage of change in increased signal intensity was calculated for the primary motor area. An ipsilateral activation index was used to compare the affected with the unaffected hemisphere. RESULTS: The percentage of change in increased signal intensity in the area of activation ranged from 4.8% +/- 0.9 to 9.2% +/- 1.2 (mean, 5.6% +/- 1.5). The ipsilateral activation index in the affected hemisphere was 0.00 to 0.38, whereas that in the unaffected hemisphere was 15.4 to infinity. The difference in the ipsilateral activation index between each hemisphere was considered significant. CONCLUSION: Our results showed increased activation in the unaffected hemisphere in patients with schizencephaly, which may reflect functional reorganization of the motor area in patients with this congenital disorder.

Adolescent↗
PubMed1996

MRI in presumed cervical anterior spinal artery territory infarcts.

We report the MRI findings in two patients with presumed cervical spinal cord infarcts in the anterior spinal artery territory. MRI revealed abnormal signal intensities and/or band-like enhancement in the anterior two-thirds of the cervical spinal cord, corresponding to the vascular territory of the anterior spinal artery. Clinically there was an anterior spinal cord syndrome.

Aged↗
PubMed1994

Isolated trigeminal sensory change due to pontine hemorrhage.

Isolated trigeminal sensory change has been rarely described as a manifestation of pontine hemorrhage. We report a 31-year-old man who developed sudden and long-lasting trigeminal sensory disturbances. Brain magnetic resonance imaging showed a hemorrhage in the right lateral pontine tegmentum corresponding to the trigeminal sensory nucleus, and the venous phase angiogram demonstrated abnormal vascular structures. Pontine hemorrhage secondary to venous malformation can be one of the causes of isolated trigeminal sensory change.

Adult↗
PubMed1994

Spectrum of lateral medullary syndrome. Correlation between clinical findings and magnetic resonance imaging in 33 subjects.

BACKGROUND AND PURPOSE: Computed tomography is insufficient in evaluation of medullary lesions. Although lateral medullary infarction is a relatively common type of cerebrovascular disease, detailed correlation between clinical findings and magnetic resonance imaging (MRI) has not yet been reported. METHODS: We studied 33 consecutive patients with lateral medullary infarction who showed appropriate MRI lesions and correlated their clinical findings with the MRI results. RESULTS: Gait ataxia (88%), vertigo/dizziness (91%), nausea/vomiting (73%), dysphagia (61%), hoarseness (55%), Horner sign (73%), and facial (85%) and hemibody (94%) sensory changes were frequent clinical findings. MRI results showed that the lesions located in the rostral part of the medulla were usually diagonal band-shaped and were associated with more severe dysphagia, hoarseness, and the presence of facial paresis, whereas the caudal lesions, situated usually in the lateral surface of the medulla, appeared to correlate with more marked vertigo, nystagmus, and gait ataxia. Nausea/vomiting and Horner sign were common regardless of the lesion location, and lesions extending ventromedially correlated with facial sensory change on the contralateral side of the lesion. CONCLUSIONS: Analysis of MRI findings in rostrocaudal and dorsoventral aspects allows us, although not unequivocally, to make anatomicoclinical correlations in the evaluation of patients with lateral medullary stroke syndrome.

Adult↗
PubMed1994

Cerebral paragonimiasis in early active stage: CT and MR features.

OBJECTIVE: Diagnosis of cerebral paragonimiasis in its early active stage is important because curative chemotherapy is possible. Accordingly, this study was undertaken to evaluate the CT and MR features of early active cerebral paragonimiasis. MATERIALS AND METHODS: We retrospectively reviewed the CT scans (n = 29) and MR images (n = 7) of the brain in 20 patients between 7 and 59 years old who had cerebral paragonimiasis in the early active stage. The diagnosis was based on a positive antibody test by enzyme-linked immunosorbent assay (ELISA) for paragonimiasis in serum and CSF. The diagnosis was confirmed surgically in seven patients. RESULTS: The most common and characteristic imaging finding was a conglomerate of ringlike enhancing lesions (grape-cluster appearance) with surrounding edema in one cerebral hemisphere in 11 patients (55%). Other nonspecific findings included a solitary ringlike lesion (n = 4) or irregular enhancing lesions (n = 2), localized hemorrhage with (n = 3) or without (n = 2) enhancing lesions, and a poorly defined non-hemorrhagic, nonenhancing lesion (n = 1). CONCLUSION: CT and MR findings of clustered ring-enhancing lesions, seen in approximately half of the cases of early cerebral paragonimiasis, are suggestive of cerebral paragonimiasis.

Adolescent↗
PubMed1994

Germinomas of the basal ganglia and thalamus: MR findings and a comparison between MR and CT.

OBJECTIVE: The purpose of this study was to describe the MR imaging appearance of germinomas in the basal ganglia and thalamus and to compare the MR findings with CT findings. MATERIALS AND METHODS: Eleven MR studies of 10 patients with pathologically proved germinomas in the basal ganglia or thalamus were retrospectively reviewed. In nine of the 10, the MR findings were compared with CT findings. All patients were male, and all except one were in their second decade of life. All the tumors were located in paraventricular areas. RESULTS: Most of the tumors were 4-7 cm in diameter. MR images showed that the tumors were mostly cystic in five patients, mostly solid with cystic components in four, and solid without cystic components in one. The solid portion mostly was isointense relative to the cerebral cortex for all MR pulse sequences. The cystic portion was hyperintense relative to CSF on T1- and T2-weighted images. MR images showed intratumoral hemorrhage in seven patients. It appeared as an area of hyperintensity on T1- and T2-weighted images in five patients and as a fluid-fluid level with marked hypointensity on T2-weighted images in two. Hemorrhage was not visualized on CT scans in any patient. Flecked or amorphous calcifications visualized on CT scans in two patients were hardly detectable on MR images. Peritumoral edema was usually minimal. CT scans and MR images obtained after injection of contrast material both showed heterogeneous and dense enhancement in the solid portions of the tumors. CONCLUSION: MR images of germinoma in the basal ganglia and thalamus show a large paraventricular mass. Cystic areas, focal hemorrhages, and minimal surrounding edema are common. Unlike CT, MR imaging allows characterization of intratumoral hemorrhage.

Adolescent↗
PubMed1994

Cerebellar MR changes in patients with olivary hypertrophic degeneration.

PURPOSE: To describe MR changes in the cerebellar cortex and the dentate nucleus in patients with inferior olivary nucleus hypertrophy. METHODS: MR scans of 11 patients with palatal myoclonus were reviewed. Among them, we selected 5 cases that showed lesions in the central tegmental tract and the ipsilateral inferior olivary nucleus. We evaluated MR changes of the cerebellar cortices and dentate nuclei contralateral to the affected inferior olivary nuclei. Evaluation was performed by side-to-side comparison in each case. Six cases were excluded, because comparison of the cerebellar hemispheres or dentate nuclei with those of the opposite sides was not possible. RESULTS: The dentate nuclei opposite affected inferior olivary nuclei showed mild to moderate shrinkage of the normal low-signal areas and increases in signal intensity on T2-weighted images in 4 of 5 patients. The cerebellar cortices on the same sides as the involved dentate nuclei showed atrophic changes in 4 of 5 patients. CONCLUSION: Our MR findings suggest that there is a degenerative process involving the dentate nucleus and the cerebellar cortex associated with the hypertrophic degeneration of the inferior olivary nucleus.

Cerebellar Cortex↗
PubMed1993

Coxiella (Q fever)-associated myelopathy.

We describe six men with a slowly progressive myelopathy characterized by asymmetric, incomplete spinal cord syndrome manifested with a thoracic sensory level, mild spastic paraparesis, and urinary incontinence. The spinal cord lesions were evident by MRI in four of them. Coxiella burnetii infection was confirmed in the blood of all patients by immunofluorescence microscopic assay (IFA) and transmission electron microscopy (TEM). In two patients, we detected C burnetii by TEM and IFA using CSF from the patients inoculated onto fresh peripheral blood lymphocyte. Four patients, treated with appropriate antibiotics, responded either with partial resolution of symptoms or arrest of further neurologic progression. In three, the MRI lesions decreased in size.

Adult↗