Biomedical subjects

Moon Hee Han

Publications and source records attributed to Moon Hee Han.

At least 37 records · Page 2Linked to original sources

PubMed2003

Embolization with autologous fibroblast-attached platinum coils in canine carotid artery aneurysms: histopathological differences from plain coil embolization.

PURPOSE: This study was designed to evaluate the effect of autologous fibroblast-attached platinum coils on the promotion of intra-aneurysmal thrombus organization. MATERIALS AND METHODS: Sidewall aneurysms were surgically created at common carotid arteries bilaterally in 5 dogs. Fibroblasts were obtained from the skins of the dogs and cultured and attached to unmodified platinum coils in a 5-day coculture. In each animal, one aneurysm was embolized with fibroblast-attached platinum coils (study group) and the other with plain platinum coils of the same size (control group). RESULTS: All aneurysms were partially occluded; the mean occlusion rate was 67%. The histologic analyses performed 2 weeks after the embolization showed more advanced organization of intra-aneurysmal thrombus in the study group than in the control group (80% versus 53%, P = 0.02). Overgrowth of the organizing tissue and parent artery stenosis did not occur. CONCLUSION: Our results suggest that autologous fibroblasts delivered with platinum coils could promote the organization of intra-aneurysmal thrombus. Although further research is needed, especially on the potential complications, endovascular treatment using autologous fibroblasts may be applied to aneurysm treatment.

Aneurysm↗

PubMed2003

Angiographic characteristics of central neurocytoma suggest the origin of tumor.

The authors retrospectively analyzed the angiographic findings performed in 17 cases with central neurocytoma to document the angiographic characteristics and suggested the origin of tumor based on the angiographic findings. Their medical records and radiological investigations were reviewed and cerebral angiographies were thoroughly examined in arterial, capillary, and venous phases. In ten cases, marked or moderate tumor staining was found whereas the staining was either scanty or absent in seven cases. In the ten cases showing marked or moderate tumor staining, the feeding vessels were originated from the ipsilateral carotid and/or vertebro-basilar system. In the venous phase, the ipsilateral thalamostriate vein, tortuous and enlarged, was elevated, and the internal cerebral vein was depressed. Thus, the venous angle of the ipsilateral side was widened at an irregular contour. Based on the characteristic displacement and the increased size of the associated venous system, it is suggested that the central neurocytoma might originate from a neuronal cell mass of the subependymal zone located on the floor of the lateral ventricle around the foramen of Monro rather than from the septum pellucidum.

Adult↗

PubMed2003

Gas generation and clot formation during electrolytic detachment of Guglielmi detachable coils: in vitro observations and animal experiment.

BACKGROUND AND PURPOSE: Recent reports describe a high rate of thromboembolic events related to Guglielmi detachable coil (GDC) use in the treatment of cerebral aneurysms. The purpose of this study was to investigate electrolysis-related changes of blood as a potential cause of thromboembolic complications associated with GDC use. METHODS: For in vitro observations, 15 GDCs (10 conventional coils and five insulated coils) were experimentally detached under microscopic observation. Three coils were detached in normal saline, five in human serum, and seven in heparinized human blood. For animal experiments, two coils were detached in two canine normal common carotid arteries with systemic heparinization. Immediately after detachment, the arteries were exposed, and clot formations were observed. RESULTS: Significant amounts of gas bubbles were observed in all in vitro observations; more were seen in conventional coils, which required longer detachment times, than in insulated coils. Gas generation started with the growth of tiny bubbles into larger ones. In insulated coils, gas was generated only at the detachment zone, and no difference between saline, serum, and blood environments was observed. During detachment within heparinized blood, clot formations of 2-3-mm diameter were observed at the detachment zones of insulated coils. Animal experiments showed clot formation at the detachment zone, and bubble entrapments around the clots were also found. CONCLUSION: The electrolytic detachment mechanism of the platinum coil can generate gas bubbles during the application of electric current. In association with electrothrombosis, this phenomenon may be a potential cause of thromboembolic complications during the treatment of cerebral aneurysms by use of GDCs.

Animals↗

PubMed2003

Delayed encephalopathy of acute carbon monoxide intoxication: diffusivity of cerebral white matter lesions.

BACKGROUND AND PURPOSE: Carbon monoxide intoxication has delayed effects on the cerebral white matter characterized by bilateral, confluent lesions that reflect diffuse demyelination. To increase our understanding of this process, we assessed the diffusion characteristics of these lesions. METHODS: Five consecutive patients with delayed encephalopathy of CO intoxication were examined with diffusion MR imaging. Diffusion-weighted images (DWIs) were obtained 25-95 days after their exposure to CO and during a relapse of neuropsychiatric symptoms, which occurred after an initial recovery. Imaging was performed at 1.5 T by using a spin-echo echo-planar sequence with diffusion gradients of 0, 500, and 1000 s/mm(2). DWIs and apparent diffusion coefficient (ADC) maps were visually evaluated, and mean ADCs were calculated from the periventricular white matter and the centrum semiovale, where confluent hyperintensity was seen on T2-weighted images. Findings were compared with those of normal-looking white matter. RESULTS: In all five patients, both T2-weighted images and DWIs showed the white matter lesions as bilateral, diffuse, confluent areas of hyperintensity in the periventricular white matter and centrum semiovale. On ADC maps, these lesions were isointense, with focal areas of hypointensity (n = 4) or diffuse hypointensity (n = 1). Mean ADC values of the white matter lesions were significantly lower than those of normal-looking white matter, regardless of their isointensity or hypointensity on ADC maps (P <.05). CONCLUSION: Bilateral, confluent, white matter lesions in patients with delayed encephalopathy of CO intoxication show decreased diffusivity.

Aged↗

PubMed2002

Decrease in genu of the corpus callosum in medication-naïve, early-onset dysthymia and depressive personality disorder.

BACKGROUND: The purpose of this study was to detect differences in regional areas of the corpus callosum (CC) in subjects with early-onset minor depression (dysthymia or depressive personality disorder) and healthy comparison subjects. Based on previous reports that have suggested reduced frontal lobe volume and reduced hemispheric lateralization in the frontal regions of the brain in depression, we hypothesized that the area of the CC that interconnects the frontal regions of the brain, i.e., the genu, will be smaller compared to that of healthy comparison subjects. METHODS: Forty female subjects with early-onset dysthymia or depressive personality disorder, as defined by the Structured Clinical Interview for DSM-III-R and the Diagnostic Interview for Depressive Personality, respectively, and age- and gender-matched healthy comparison subjects (n = 42) were recruited (age: 21.4 +/- 2.1 and 20.9 +/- 2.8 years, respectively). All subjects were psychotropic medications-naïve and right-handed. A 1.5T GE Sigma scanner was used to acquire 124 1.5-mm-thick contiguous coronal images. Midsagittal slice images were carefully selected from reconstructed magnetic resonance images both from native and stereotaxic space to measure seven regional areas of the CC. RESULTS: There were significant diagnosis by CC region interactions [F(6,480) = 4.06, p <.001; F(6,480) = 3.30, p =.003, native and stereotaxic space, respectively]. Early-onset minor depression subjects had a 9.9% (native space) and 6.9% (stereotaxic space) smaller genu of the CC compared to the healthy comparison subjects (the Newman-Keuls post hoc test, p =.005 and.019, native and stereotaxic space, respectively). Early-onset minor depression subjects also had a 7.8% smaller posterior midbody relative to the comparison subjects (the Newman-Keuls post hoc test, p =.033) only in the native space. Severity of current depressive symptoms or duration of illness did not correlate with the size of the genu or the posterior midbody parts of the CC. CONCLUSIONS: These results suggest frontal lobe structural, and possibly functional, abnormalities in the brain in young female adults with a milder spectrum of depression, i.e., DSM-IV early-onset dysthymia or depressive personality disorder. The present findings point out the possible role of frontal lobe abnormality in pathophysiology of early-onset minor depression.

Adolescent↗

PubMed2002

Craniofacial cavernous venous malformations: percutaneous sclerotherapy with use of ethanolamine oleate.

PURPOSE: To assess the efficacy of percutaneous sclerotherapy with use of ethanolamine oleate for craniofacial cavernous venous malformations. MATERIALS AND METHODS: From 1991 to 2001, sclerotherapy (average of two procedures per patient) was performed in 29 patients (mean age, 22 y; 10 male) with craniofacial venous malformations. Direct puncture venography was performed with use of water-soluble contrast media to delineate the extent of the lesions. CO(2) gas was used as contrast medium in addition to water-soluble contrast media in five patients in whom lesions had large nondependent areas. Coil embolization with a transvenous approach was performed in two patients when the lesions had large draining veins. Then, a mixture of 5% ethanolamine oleate and iodized oil (ratio, 5:1-5:2) was injected manually into the lesions under fluoroscopic guidance to monitor the process. A total of 59 procedures were performed. Clinical follow-up was obtained in 25 of 29 patients. The duration of follow-up ranged from 10 days to 6 years (mean, 8.5 mo). The effectiveness of sclerotherapy was assessed on the basis of clinical, surgical, and radiologic findings. RESULTS: The procedures were effective in 14 of 16 patients who underwent sclerotherapy only. The procedures were beneficial for all nine patients who underwent sclerotherapy and surgery. There was no skin injury or nerve damage. The trismus that appeared in two patients with lesions in the masticator space was treated well by conservative therapy. CONCLUSION: Percutaneous sclerotherapy with use of ethanolamine oleate is a safe and effective treatment of craniofacial cavernous venous malformations. However, renal function was not specifically evaluated after treatment, and therefore occult renal dysfunction cannot be excluded.

Adolescent↗

PubMed2002

A technique for safe withdrawal of a catheter tip that hooks a coil loop.

In cerebral aneurysm embolization with GDCs, coil movement and subsequent coil protrusion or migration may occur during catheter withdrawal. Coil migration or protrusion usually does not produce clinical problems, but sometimes it may do. Because the consequences of coil movement cannot be anticipated exactly, coil motion during a catheter withdrawal makes interventionists nervous. The authors report on a technique for safe withdrawal of a catheter tip that hooks a coil loop using a small soft coil.

Cerebral Angiography↗

PubMed2002

Clinical characteristics of dural arteriovenous fistula.

Intracranial dural arteriovenous fistula (DAVF) is an uncommon neurosurgical condition; in particular, it has been infrequently reported in Korea. To understand the general clinical characteristics of DAVFs, the authors reviewed 53 cases and analyzed factors affecting DAVF hemorrhage of and treatment outcome. Since 1980 we have encountered 480 pial and 53 DAVFs, a ratio of 9.1 to 1. The age of these patients ranged from 1 month to 71 years, the most common being in the 6th decade, and females exceeded males by 1.65 to 1. All lesions except three were single, and symptoms were related to location and the venous drainage pattern. The most common location was the cavernous sinus, accounting for about 64% of cases, with the result that the most common clinical symptoms of DAVFs were ocular, namely proptosis and chemosis. The next was tinnitus also found in transverse-sigmoid sinus DAVFs. Intracranial hemorrhage was seen in eight cases,(15%) the primary cause of hemorrhage was retrograde intracranial venous drainage (P=0.017), and one hemorrhage was observed in cases with no intracranial venous drainage. Intracranial hemorrhage was more frequently in transverse-sigmoid than cavernous sinus DAVFs (P=0.049), and this proved to be so even where there was intracranial venous drainage. However, two of 34 patients with cavernous DAVFs became blind in one eye, demonstrating that in such patients, the clinical course could be aggressive. Thirteen patients were treated conservatively. The conservative treatment group was comprised of 13 patients, two of three patients with transverse-sigmoid sinus DAVF expired, and 7 of 10 with cavernous sinus DAVF experienced a clinical improvement or cure. Surgical excision was performed in only two patients. A total of 39 patients underwent embolization; clinical cure was achieved in 13, improvement of symptoms in 12, an unchanged or aggravated result occurred in 9, one died, and four were lost to follow up. During intervention, there was one hemorrhagic complication, owing to obstruction of the venous outflow with embolic materials. In this study, the most common location of DAVFs was the cavernous sinus. The cortical venous drainage remains the primary determinant of intracranial hemorrhage. Common indications for treatment include hemorrhage and neurological deficit. Endovascular treatment is preferred in the majority of cases except tentorial DAVF. The goal of embolization in cavernous DAVF is the alleviation of symptoms, not angiographic cure. But transverse-sigmoid sinus DAVF with venous restriction and leptomeningeal drainage should be treated aggressively.

Adolescent↗

PubMed2002

Computed tomographic findings of distensible orbital venous anomalies.

PURPOSE: To describe the CT findings of distensible orbital venous anomalies. METHODS: We reviewed the records of 17 consecutive patients who met the imaging criteria for orbital venous anomalies. We analyzed the clinical data and the CT scans qualitatively and quantitatively. RESULTS: Distensible venous anomalies usually occupied both intraconal and extraconal spaces of the orbit (65%). The contour of the mass was ovoid or fusiform in 3 of the orbits (18%) and tubular or lobular in 14 orbits (82%). The optic nerve was encased by the mass in 8 orbits. Changes in the adjacent bone were detected in 9 orbits. The average volume of the venous anomalies was 1.1 mL in the axial scan and 5.7 mL in the coronal scan. The patients who showed clinically evident exophthalmos on the Valsalva maneuver had larger volumes than those who did not. CONCLUSIONS: The orbital structures adjacent to the distensible orbital venous anomalies were vulnerable to intermittent compression. CT scans, including both postcontrast axial and coronal images, were useful in demonstrating the presence of distensible venous anomalies, even in cases with no apparent exophthalmos on the Valsalva maneuver.

Adolescent↗

PubMed2002

Intraosseous dural arteriovenous fistula of the skull base associated with hearing loss. Case report.

The most common clinical presentations of dural arteriovenous fistulas (DAVFs) are bruit, headache, increased intracranial pressure, and intracranial hemorrhage. In particular locations, such as the cavernous sinus or middle cranial fossa, cranial nerve involvement due to dural arterial steal or venous occlusion may develop. A case in which a DAVF is associated with hearing loss, however, has not previously been reported. The authors report a case in which an intraosseous DAVF and associated hearing loss probably resulted from cochlear nerve or vascular compression caused by the draining vein or nidus of the DAVF.

Adolescent↗

PubMed2002

Intraarterially administered abciximab as an adjuvant thrombolytic therapy: report of three cases.

The intravenous administration of abciximab can be used as an adjuvant therapy to facilitate thrombolysis for acute cerebrovascular occlusion. However, to our knowledge, the intraaterial administration of abciximab has not been reported. We recently treated three patients with acute thrombosis of the cerebral arteries by using an intraarterial infusion of urokinase and abciximab. Even with small doses, we achieved rapid and complete recanalization without complications. We believe that the intraarterial infusion of abciximab may be promising for effective and safe recanalization of acute thrombotic occlusion of cerebral arteries.

Abciximab↗

PubMed2002

A technique of GDC embolization for deeply bilobulated aneurysms.

The endovascular occlusion of deeply bilobulated aneurysms is a technical challenge. Recently, we successfully treated three patients with deeply bilobulated aneurysms by using Guglielmi detachable coils. The embolization technique was conventional, but it required several special technical considerations. In this report, we describe the technique of coil embolization of deeply bilobulated aneurysms.

Aged↗

PubMed2002

Apparent diffusion coefficient value of the hippocampus in patients with hippocampal sclerosis and in healthy volunteers.

BACKGROUND AND PURPOSE: MR diffusion-weighted (DW) imaging with apparent diffusion coefficient (ADC) has had widespread use clinically in a variety of intracranial diseases; however, only a few studies report ADC changes in patients with hippocampal sclerosis. We sought to determine the ability of ADC to lateralize the epileptogenic lesion in patients with hippocampal sclerosis. METHODS: Nineteen healthy volunteers and 18 patients with intractable temporal lobe epilepsy whose MR imaging diagnosis was unilateral hippocampal sclerosis were examined prospectively with DW imaging and ADC mapping. DW images were obtained at 1.5 T with a spin-echo echo-planar sequence (6500/103 [TR/TE]) with variable diffusion gradients. ADCs were calculated from bilateral hippocampi. The ability of DW imaging and ADC to lateralize the lesion was evaluated visually and by comparing ADC values between healthy volunteers and patients with hippocampal sclerosis. RESULTS: In all patients, visual assessment of DW images failed to lateralize the lesion. However, the mean ADC value measured at the hippocampal area was significantly higher on the lesion side than on the contralateral side (P <.001). The overall correct lateralization rate of ADC was 100% (18 of 18 patients). Mean ADC in sclerotic hippocampi was also significantly higher than that in healthy volunteers. The normal-appearing hippocampus of the contralateral side in the patients had higher ADC values compared with those of healthy volunteers (P =.045). CONCLUSION: ADC can be used as a complementary tool in lateralizing the epileptogenic lesion in patients with hippocampal sclerosis, although the practical role of ADC value is yet to be determined in patients with inconclusive MR imaging findings.

Adolescent↗

PubMed2002

Technical problems associated with new designs of Guglielmi detachable coils.

BACKGROUND AND PURPOSE: Recently, we experienced several technical problems that were directly related to new designs of Guglielmi detachable coils (GDCs). We herein present cases involving those problems and propose probable causes. METHODS: We reviewed the clinical and angiographic data of 269 consecutive patients with intracranial aneurysms who had been treated with GDCs between May 1996 and October 2001. We focused on newly encountered technical problems: spontaneous premature coil detachment, backward slipping of the coil into the microcatheter lumen after detachment, and undesirable detachment of the coils at the parent artery. The occurrence and clinical consequences of the problems were investigated before and after the introduction of a new GDC (SynerG) design. Additionally, to confirm the potential causal relationship, in vitro observations and simulation tests were performed. RESULTS: Of the 269 patients, 69 underwent embolization between March and October of 2001. Among those, we encountered technical problems in 10 (14.5%) cases. The overall number of events was 12, including spontaneous detachment (n = 5), backward slipping of the coil into the microcatheter lumen after detachment (n = 4), and undesirable coil detachment with a segment of the coil remaining at the parent artery (n = 3). No similar problems occurred among the 200 patients treated during the period between May 1996 and February 2001, when the new design coil had not yet been introduced. In vitro observations suggested that the long and stiff segment of the SynerG coil, especially the SR type, was a highly probable cause of these technical problems. CONCLUSION: Our clinical experience showed a high incidence of technical problems, and in vitro observations suggested that the new GDC designs could be responsible for them. For safe aneurysm treatment, details of embolization techniques should be modified.

Adult↗

PubMed2002

Marker alignment for Guglielmi detachable coil embolization: practical considerations.

BACKGROUND AND PURPOSE: Aneurysm embolization is not without risk: numerous technical aspects are considered before, during, and after the procedure. The purpose of this study was to show the position of the detachment zone of a Guglielmi detachable coil (GDC) with respect to the catheter tip for various microcatheters and marker alignments. METHODS: Six types of commonly used microcatheters were tested (Excel-14, Excelsior, FasTracker-10, Prowler-10, Prowler-14, and Rebar-14). First, the catheter markers and the distance from the catheter tip to the distal end of the proximal and distal markers of each catheter were compared. Second, the coil maker was aligned with the catheter marker. Third, the distal 3 cm of the microcatheter was modified by random shaping, with or without steaming. Last, marker alignment was tested with resterilized microcatheters (ethylene oxide gas sterilization). RESULTS: The length of the catheter marker and the distance between the catheter tip and the distal end of the proximal and distal catheter markers varied among the microcatheters. Sometimes, they varied even within the same microcatheter type. When a GDC was advanced until the proximal end of the marker on the delivery wire was exactly distal to the proximal catheter marker, the coil detachment zone was positioned at approximately 1.0 to 1.5 mm outside the catheter tip. Steaming or shaping of the distal 3 cm of the microcatheters resulted in the GDCs protruding more from the catheter tip. Resterilization also had an effect of marker distance shortening. Microcatheters were easily stretched by usual handling, such as removing a shaping mandrel from the catheter tip. CONCLUSION: Our study shows that proper marker alignment is influenced by many factors, including microcatheter type, steaming, shaping, sterilization, and manual handling.

Catheterization↗

PubMedDate not supplied

Nasopharyngeal carcinoma: posttreatment changes of imaging findings.

OBJECTIVE: The purpose of this study was to determine the radiologic results of nasopharyngeal carcinoma (NPC) that showed complete responses on follow-up imaging studies after radiation therapy. MATERIALS AND METHODS: This study is a retrospective review of 23 patients (18 male, 5 female, aged 15-71 years; mean age, 48.5 years) affected with NPC, from August 1995 to July 2000, who were examined with magnetic resonance imaging or computed tomography scan before and after either radical radiotherapy or chemoradiotherapy. The median follow-up was 24.7 months and ranged from 12 to 48 months. We analyzed the primary tumors by ascertaining/measuring tumor size, depth, middle ear effusion, skull base invasion, and lymphadenopathy. The treatment responses for primary tumors were classified as either atrophy, scar (asymmetric elevation without enhancement), or normalized. The tumor response and the appearance of bone regeneration in the previous destructive part of the skull base were also recorded. RESULTS: The 23 patients consisted of 12 superficial tumors, for whom treatment results were normalized in 10, atrophy in 1, and scar in 1 and 11 deep tumors for whom treatment results were scar in 6, normalized in 3, and atrophy in 2. Skull base invasion was detected in 6 patients, 5 of whom showed complete healing of skull base destruction after radiotherapy. However, the other patient exhibited an unusual hyperostotic change in the skull base mimicking fibrous dysplasia of the skull base. CONCLUSIONS: The superficial tumors tended to be radiologically normalized even when they were large. However, the deep tumors mainly changed to scar after radiation therapy. On the other hand, skull base invasion could be normalized after radiotherapy.

Adolescent↗

PubMedDate not supplied

Nodular fasciitis of the head and neck: radiographic findings.

Nodular fasciitis is an unusual benign reactive process of the soft tissues related to the fascia and characterized by fibroblastic proliferation. Clinical findings and radiologic aspects of six cases are described [four computed tomography (CT), two ultrasonography (US), one magnetic resonance (MR)]. They were located in the infrahyoid anterior triangle (n=3), prevertebral space (n=2), and masticator space (n=1). Most of these lesions showed moderate to strong enhancement on CT or MR imaging, and were partially embedded in the adjacent muscle with preservation of smooth margin of the muscle. Most cases showed a benign nature, except one case in the prevertebral space which showed aggressive nature with jugular fossa destruction and intracranial extension.

Adult↗

PubMedDate not supplied

Changes of flow characteristics by stenting in aneurysm models: influence of aneurysm geometry and stent porosity.

An endovascular technique using a stent has been developed and successfully applied in the treatment of wide neck aneurysms. A stent can facilitate thrombosis in the aneurysm pouch while maintaining biocompatible passage of the parent artery. Insertion of the stent changes the flow characteristics inside the aneurysm pouch, which can affect the intra-aneurysmal embolization process. The purpose of this study is to clarify the velocity and wall shear stress changes that are caused by stenting in fusiform and lateral aneurysm models. We used a flow visualization technique that incorporated a photochromic dye in order to observe the flow fields and measure the wall shear rates. The intra-aneurysmal flow motion was significantly reduced in the stented aneurysm models. Coherent inflow along the distal wall of the aneurysm was diminished and inflow was distributed along the pores of the stent wall in the stented models. Also, sluggish intra-aneurysmal vortex motion was well maintained in the stented aneurysm models during the deceleration phase. A less porous stent generally reduced the intraneurysmal fluid motion further, but the porosity effect was not significant. The magnitude and pulsatility of the wall shear rate were reduced by stenting, and the reductions were more significant in the lateral aneurysm models compared to the fusiform aneurysm models. The hemodynamic changes that were observed in our study can help explain the efficacy of in vivo thrombus formation caused by stenting.

Aneurysm↗