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Hsieh YC, Chu YC, Lin SM, Tsou MY, Tsai SK, Lee TY. Comparison of recovery characteristics of sevoflurane and halothane for outpatient surgery in infants. ZHONGHUA YI XUE ZA ZHI = CHINESE MEDICAL JOURNAL; FREE CHINA ED 1999; 62:801-6. [PMID: 10575809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
BACKGROUND Sevoflurane, a newly approved potent inhaled anesthetic in Taiwan, provides rapid emergence from anesthesia in adults and children. Clinically, it is difficult to accurately assess the rate of recovery from anesthesia in infants. This study was designed to compare the emergence characteristics of halothane with those of sevoflurane having recourse to a respiratory agent monitor in infants undergoing outpatient surgery. METHODS Forty infants of ASA class I, scheduled for day-case urologic surgery were studied. Patients were randomly allocated to two groups of 20. Sevoflurane or halothane was used as the inhaled anesthetic. Toward the end of surgery, sevoflurane or halothane was turned off. The concentrations of exhaled sevoflurane or halothane were read every minute after its discontinuation until extubation. The decay curve of the exhaled concentration of either agent was recorded minute by minute for 10 minutes. The time intervals from discontinuation of the inhalation agent to spontaneous movement and tracheal extubation were recorded. Untoward side-effects during emergence were also compared. RESULTS Sevoflurane was eliminated faster than halothane. Based on the decay curves of the exhaled concentrations of the two agents, the time constant for halothane was 2.59 minutes and that for sevoflurane was only 1.43 minutes. The time from discontinuation of agent to extubation was also shorter for sevoflurane. Postoperative restlessness or agitation occurred more frequently in infants who received sevoflurane, although the difference was of no statistical significance. CONCLUSIONS Sevoflurane is superior to halothane for rapid elimination in infant outpatient surgery as gauged by observation of end-tidal concentration elimination curves recorded with a respiratory agent monitor. No other postoperative side-effect was evident in sevoflurane anesthesia.
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Henderson E, McKinnon G, Lee TY, Rutt BK. A fast 3D look-locker method for volumetric T1 mapping. Magn Reson Imaging 1999; 17:1163-71. [PMID: 10499678 DOI: 10.1016/s0730-725x(99)00025-9] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We introduce a fast technique, based on the principles of the 2D Look-Locker T1 measurement scheme, to rapidly acquire the data for accurate maps of T1 in three dimensions. The acquisition time has been shortened considerably by segmenting the acquisition of the k(y) phase encode lines. Using this technique, the data for a 256 x 128 x 32 volumetric T1 measurement can be acquired in 7.6 min. T1 measurements made in phantoms with T1s between 200 and 1200 ms had an accuracy of 4% and a reproducibility of 3.5%. Measurements of T1 made in normal brain using the fast 3D sequence corresponded well with inversion-recovery fast spin-echo measurements.
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Nabavi DG, Cenic A, Craen RA, Gelb AW, Bennett JD, Kozak R, Lee TY. CT assessment of cerebral perfusion: experimental validation and initial clinical experience. Radiology 1999; 213:141-9. [PMID: 10540654 DOI: 10.1148/radiology.213.1.r99oc03141] [Citation(s) in RCA: 201] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To validate a dynamic single-section computed tomographic (CT) method to measure cerebral blood volume (CBV) and cerebral blood flow (CBF) by using a noncarotid artery as the input and to demonstrate the feasibility of this method in a pilot series of patients. MATERIALS AND METHODS Twelve dynamic contrast material-enhanced CT studies were performed in beagles. CBV, CBF, and mean transit time (MTT) values were calculated by using an internal carotid artery (ICA) and a noncarotid artery as the input artery to the brain. Patient studies with use of the radial artery as the input were performed (a) repetitively in two patients after subarachnoid hemorrhage, (b) in a patient with a symptomatic ICA occlusion before and after the intravenous injection of 1 g of acetazolamide, and (c) in a patient with a malignant brain tumor. RESULTS Linear regression analyses revealed highly significant correlations (P < .001) between CBV (r, 0.98; slope, 0.96), CBF (r, 0.89; slope, 0.87), and MTT (r, 0.80; slope, 0.76) values calculated with the ICA and the noncarotid inputs. The CT-derived patient data correlated well with ancillary clinical and neuroradiologic findings. CONCLUSION Dynamic single-section CT scanning to measure CBV and CBF on the basis of a noncarotid input is a highly accessible and cost-effective blood flow measurement technique.
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Lin SH, Su NY, Hseu SS, Ting CK, Yien HW, Cheng HC, Lee TY. Anesthetic managements of the patients with giant mediastinal tumors--a report of two cases. ACTA ANAESTHESIOLOGICA SINICA 1999; 37:133-9. [PMID: 10609346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
Abstract
Anesthesia for patients with a huge anterior mediastinal tumor is a well-known challenge and trial to all the anesthesiologists. The tumor mass which directly compresses the trachea and bronchus induces hypoxia and asphyxia, eventuating in cardiac arrest or even fatality in the process of general anesthesia. In selection of anesthetic technique, general anesthesia is deliberately avoided if not mandatory or spontaneous respiration should be strictly preserved by all means if obligatory. Our surgical colleagues are usually not so familiar with this potentially life-threatening situation as are the anesthesiologists, and bad communications and interactions between the two may court disaster. Here we reported 2 cases: the former was an immediate mortality in a youth with a giant anterior mediastinal tumor undergoing excisional biopsy of a neck mass under general anesthesia, and the latter was a successful anesthetic management in a woman with a giant mediastinal tumor receiving abdominal total hysterectomy for cervical cancer in situ under spinal anesthesia. The hazards of general anesthesia in these patients and the importance of comprehending preanesthetic preparations were reviewed and discussed. Moreover, we address that whenever one has shot his bolt still futile to improve the respiratory crisis in a case with mediastinal tumor, try to ventilate the patient in a prone position as it has clinical importance in ventilation and oxygenation.
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Tsao CM, Yuan HB, Neu SH, Lan CJ, Hu JS, Lui PW, Lee TY. Postoperative pulmonary edema after cervical spine surgery--a case report. ACTA ANAESTHESIOLOGICA SINICA 1999; 37:147-50. [PMID: 10609348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
Abstract
Injury of the cervical spine may cause serious complications and neurological sequelae. Recently, a patient with C1-2 spinal cord compression developed pulmonary edema postoperatively associated with unstable hemodynamics, which might result from overzealous fluid administration in order to correct neurogenic shock during anesthesia. Therefore, early recognition and timely use of vasoconstrictors, together with judicious fluid replacement are important in the anesthetic management of patients with cervical spine injury undergoing surgery. In addition, the placement of pulmonary artery catheter is crucial for assessing the cardiac function and fluid status.
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Wu YC, Ho CM, Tsou MY, Hung JH, Yuan CC, Lee TY, Ng HT. Successful management of malignant hyperthermia susceptibility during cesarean hysterectomy for postpartum hemorrhage. Acta Obstet Gynecol Scand 1999; 78:738-9. [PMID: 10468070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
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Tofts PS, Brix G, Buckley DL, Evelhoch JL, Henderson E, Knopp MV, Larsson HB, Lee TY, Mayr NA, Parker GJ, Port RE, Taylor J, Weisskoff RM. Estimating kinetic parameters from dynamic contrast-enhanced T(1)-weighted MRI of a diffusable tracer: standardized quantities and symbols. J Magn Reson Imaging 1999; 10:223-32. [PMID: 10508281 DOI: 10.1002/(sici)1522-2586(199909)10:3<223::aid-jmri2>3.0.co;2-s] [Citation(s) in RCA: 2382] [Impact Index Per Article: 95.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
We describe a standard set of quantity names and symbols related to the estimation of kinetic parameters from dynamic contrast-enhanced T(1)-weighted magnetic resonance imaging data, using diffusable agents such as gadopentetate dimeglumine (Gd-DTPA). These include a) the volume transfer constant K(trans) (min(-1)); b) the volume of extravascular extracellular space (EES) per unit volume of tissue v(e) (0 < v(e) < 1); and c) the flux rate constant between EES and plasma k(ep) (min(-1)). The rate constant is the ratio of the transfer constant to the EES (k(ep) = K(trans)/v(e)). Under flow-limited conditions K(trans) equals the blood plasma flow per unit volume of tissue; under permeability-limited conditions K(trans) equals the permeability surface area product per unit volume of tissue. We relate these quantities to previously published work from our groups; our future publications will refer to these standardized terms, and we propose that these be adopted as international standards.
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Lee TY, Sun YN, Lin YC, Lin L, Lee C. Three-dimensional facial model reconstruction and plastic surgery simulation. IEEE TRANSACTIONS ON INFORMATION TECHNOLOGY IN BIOMEDICINE : A PUBLICATION OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY 1999; 3:214-20. [PMID: 10719485 DOI: 10.1109/4233.788583] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Facial model reconstruction and surgical simulation are essential to plastic surgery in today's medicine. Both can help surgeons to design appropriate repair plans and procedures prior to actual surgery. In this paper, we exploit a metamorphosis technique in our new design. First, using metamorphosis and vision techniques, we can establish three-dimensional facial models from a given photo. Second, we design several morphing operators, including augmentation, cutting, and lacerating. Experiments show that the proposed algorithms can successfully create acceptable facial models and generate realistically visual effects of surgical simulation.
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Tofts PS, Brix G, Buckley DL, Evelhoch JL, Henderson E, Knopp MV, Larsson HB, Lee TY, Mayr NA, Parker GJ, Port RE, Taylor J, Weisskoff RM. Estimating kinetic parameters from dynamic contrast-enhanced T(1)-weighted MRI of a diffusable tracer: standardized quantities and symbols. J Magn Reson Imaging 1999; 10:223-232. [PMID: 10508281 DOI: 10.1002/(sici)1522-2586(199909)10:3<223∷aid-jmri2>3.0.co;2-s] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023] Open
Abstract
We describe a standard set of quantity names and symbols related to the estimation of kinetic parameters from dynamic contrast-enhanced T(1)-weighted magnetic resonance imaging data, using diffusable agents such as gadopentetate dimeglumine (Gd-DTPA). These include a) the volume transfer constant K(trans) (min(-1)); b) the volume of extravascular extracellular space (EES) per unit volume of tissue v(e) (0 < v(e) < 1); and c) the flux rate constant between EES and plasma k(ep) (min(-1)). The rate constant is the ratio of the transfer constant to the EES (k(ep) = K(trans)/v(e)). Under flow-limited conditions K(trans) equals the blood plasma flow per unit volume of tissue; under permeability-limited conditions K(trans) equals the permeability surface area product per unit volume of tissue. We relate these quantities to previously published work from our groups; our future publications will refer to these standardized terms, and we propose that these be adopted as international standards.
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Tsao CM, Ho CM, Tsai SK, Lee TY. Effects of estrogen on autotomy in normal and ovariectomized rats. Pharmacology 1999; 59:142-8. [PMID: 10450069 DOI: 10.1159/000028314] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Gonadal hormones may modulate analgesia responses induced by acute stress in humans and rats. To evaluate the effects of gonadal hormones in modifying neuropathic pain, we measured autotomy changes following sciatic nerve resection in ovariectomized rats and in the presence of estrogen replacement. Two groups of female rats were subjected to ovariectomy and sham surgery. Each group was then divided into two subgroups receiving subcutaneously sesame oil with or without estradiol benzoate (5 microg/day/rat). All rats then underwent sciatic nerve resection in one hindlimb. Degree of self-mutilation was measured daily for 8 weeks. Estradiol treatment resulted in significantly lower autotomy scores in ovariectomized rats (3.6 +/- 0.6 vs. 5.5 +/- 0.3, p < 0.01) and in sham-operated rats (3.4 +/- 0.7 vs. 5.1 +/- 0.4, p < 0.05). The results of this study indicate that estrogen can modify the autotomy behavior, an indicator of neuropathic pain, in rats after nerve injury.
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Chia YY, Liu K, Chow LH, Lee TY. The preoperative administration of intravenous dextromethorphan reduces postoperative morphine consumption. Anesth Analg 1999; 89:748-52. [PMID: 10475318 DOI: 10.1097/00000539-199909000-00041] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
UNLABELLED We evaluated the effect of dextromethorphan on postoperative pain management. Sixty ASA physical status I-III female patients undergoing major abdominal surgery underwent standardized general anesthesia. Thirty patients received an i.v. infusion of dextromethorphan 5 mg/kg before anesthetic induction (Pre group), whereas the remaining 30 patients received the same volume of isotonic sodium chloride solution, followed by a postoperative i.v. infusion of dextromethorphan 5 mg/kg (Post group). Patients in the Pre group received the same volume of isotonic sodium chloride solution postoperatively. All patients were then treated with patient-controlled i.v. analgesia, which administered a 0.6-mg bolus of morphine on demand (maximal 4 h dose 20 mg). The mean visual analog pain score during cough or movement and at rest were similar in the two groups in the first 3 days postoperatively. However, Post group patients consumed more morphine than Pre group patients during the first 2 days (P < 0.01). The sedation scores, patient satisfaction, and the incidence of morphine-related side effects were similar between the two groups. We conclude that the preoperative administration of dextromethorphan 5 mg/kg reduces postoperative morphine consumption compared with postoperative administration. IMPLICATIONS In this double-blinded study, we found that the preoperative administration of i.v. dextromethorphan 5 mg/kg, compared with postoperative administration, reduces postoperative morphine consumption, which may provide clinical evidence of preemptive or preventive analgesic effects of dextromethorphan.
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Lee TY, Gotlieb AI. Early stages of endothelial wound repair: conversion of quiescent to migrating endothelial cells involves tyrosine phosphorylation and actin microfilament reorganization. Cell Tissue Res 1999; 297:435-50. [PMID: 10460490 DOI: 10.1007/s004410051370] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Endothelial repair to reestablish structural integrity following wounding is a complex process. Since the actin cytoskeleton undergoes specific changes in distribution as quiescent endothelial cells switch to activated migrating cells over a 6-h period following wounding (Lee et al. 1996), we studied tyrosine phosphorylation in association with actin microfilaments and adhesion proteins using double immunofluorescent confocal microscopy. We showed that in a confluent monolayer phosphotyrosine localized at the periphery of the cell at vinculin cell-cell adhesion sites within the actin-dense peripheral band (DPB) and centrally at talin/vinculin cell-substratum adhesion sites at the ends of central microfilaments. Over a period of 6 h following in vitro wounding there was a reduction of peripheral phosphotyrosine associated with the loss of both cell-cell adhesion sites and the DPB (stage I). Concomitantly, an increase in central phosphotyrosine was associated with an increase in cell-substratum adhesion sites and central microfilaments parallel to the wound edge (stage II), which subsequently redistributed perpendicular to the wound edge (stage III). We also localized FAK and paxillin at the ends of parallel and perpendicular central microfilaments. Immunoprecipitation of paxillin showed increased phosphotyrosine and protein levels when prominent central microfilaments were present and underwent remodeling. Inhibition of tyrosine kinases by genistein and tyrosine phosphatases by sodium orthovanadate resulted in reduced endothelial repair associated with disruption of adhesion site formation and central microfilament formation/redistribution in each stage of repair. We suggest that tyrosine phosphorylation of adhesion proteins, such as paxillin, may be important in regulating the early stages of endothelial wound repair.
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Lee TY, Chin GS, Kim WJ, Chau D, Gittes GK, Longaker MT. Expression of transforming growth factor beta 1, 2, and 3 proteins in keloids. Ann Plast Surg 1999; 43:179-84. [PMID: 10454326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
Keloids represent a pathological response to cutaneous injury, creating disfiguring scars with no known satisfactory treatment. They are characterized by an excessive accumulation of extracellular matrix, especially collagen. Transforming growth factor beta (TGF-beta) has been implicated in the pathogenesis of keloids. The three TGF-beta isoforms identified in mammals (TGF-beta1, -beta2, and -beta3), are thought to have different biological activities in wound healing. TGF-beta1 and TGF-beta2 are believed to promote fibrosis and scar formation, whereas TGF-beta3 has been shown to be either scar inducing or reducing, depending on the study. The aim of this study was to characterize expression of TGF-beta isoforms in keloids at the protein level using Western blot analysis. The authors found that TGF-beta1 and -beta2 proteins were at higher levels in keloid fibroblast cultures compared with normal human dermal fibroblast cultures. In contrast, the expression of TGF-beta3 protein was comparable in both the normal (N = 3) and keloid (N = 3) cell lines. These findings, demonstrating increased TGF-beta1 and -beta2 protein expression in keloids relative to normal human dermal fibroblasts further support the roles of TGF-beta1 and -beta2 as fibrosis-inducing cytokines.
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Tang GJ, Tang JJ, Lin BS, Kong CW, Lee TY. Factors affecting gentamicin pharmacokinetics in septic patients. Acta Anaesthesiol Scand 1999; 43:726-30. [PMID: 10456812 DOI: 10.1034/j.1399-6576.1999.430707.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND This prospective, comparative study was designed to estimate the volume of distribution (Vd) and elimination rate constant (K(e)) of gentamicin and to determine the clinical factors affecting the pharmacokinetics of gentamicin in different stages of sepsis. METHOD Seventy-seven critically ill patients treated with gentamicin for gram-negative sepsis were included. These septic patients were divided into hyperdynamic septic and hypodynamic septic groups according to cardiac index. Twenty-seven patients who received postoperative prophylactic gentamicin were recruited as controls. RESULTS Fifty-two patients in the hyperdynamic septic group had a significantly larger Vd than those in the hypodynamic septic and control groups. The Vd was correlated significantly with both Acute Physiological Score (APS) (r=0.340, P<0.01) and cardiac index (r=0.394, P<0.01). The K(e) of gentamicin correlated significantly with both blood urea nitrogen (BUN) (r= 0.565, P<0.01) and serum creatinine level (r=0.563, P<0.01). CONCLUSION The increased Vd in the septic patients was related to the severity of illness and magnitude of cardiac output. The K(e) of gentamicin was correlated with the serum creatinine level.
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Cheng YF, Chen CL, Huang TL, Chen TY, Lee TY, Chen YS, Wang CC, de Villa V, Goto S, Chiang YC, Eng HL, Jawan B, Cheung HK. Magnetic resonance of the hepatic veins with angular reconstruction: application in living-related liver transplantation. Transplantation 1999; 68:267-71. [PMID: 10440400 DOI: 10.1097/00007890-199907270-00019] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
BACKGROUND Preoperative mapping of the hepatic venous system of the partial liver graft is indispensable to the success of living-related liver transplantation. We assessed the accuracy of magnetic resonance (MR) venography with angular reconstruction in depicting the tributaries of the middle hepatic vein and left hepatic vein in the donors, which was essential in graft retrieval and venoplasty. METHODS Nineteen living-related liver transplantation donors underwent a pretransplantation survey, including sonography and MRI for hepatic venous evaluation. T1-weighted images were reconstructed manually, using the inferior vena cava as a fixed point for tilting to produce an oblique plane image where both the middle hepatic vein and left hepatic vein could be demonstrated draining into the inferior vena cava. The reconstructed images of the hepatic veins were compared with preoperative sonography, intraoperative sonography, and operative findings. RESULTS Preoperative sonography and MR findings correlated well with the operative findings in the major hepatic veins. The MR venography of the ramification of the hepatic veins has an accuracy of 93%, the sonography, 84%. Sonography is slightly inferior in the evaluation of the hepatic vein in segment 4 and the left superior hepatic vein, with an accuracy of 73% and 67%, respectively. CONCLUSION MR venography with angular reconstruction is accurate in depicting the complex distribution of the hepatic veins of the left liver, providing important information for decision making as to the cutting plane during graft retrieval and the method of venoplasty and anastomosis. Thus, unnecessary blood loss could be avoided and vascular complications could be prevented, as these conditions would be unacceptable for a healthy living donor. We propose that MR venography, a rapid and reliable technique, is an appropriate alternative examination or complementary modality to sonography in the pretransplantation evaluation of the living donor.
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Nabavi DG, Cenic A, Dool J, Smith RM, Espinosa F, Craen RA, Gelb AW, Lee TY. Quantitative assessment of cerebral hemodynamics using CT: stability, accuracy, and precision studies in dogs. J Comput Assist Tomogr 1999; 23:506-15. [PMID: 10433275 DOI: 10.1097/00004728-199907000-00003] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE The limited clinical availability of currently used methods to measure regional cerebral blood volume (CBV) and cerebral blood flow (CBF) represents an important restriction. We undertook this study to evaluate a new dynamic CT method to measure CBV and CBF in normal and ischemic tissue. METHOD A total of 21 dynamic CT studies were performed in seven male beagles. The contrast enhancement curves of the carotid arteries and of various brain regions were deconvolved to obtain CBV and CBF. The stability of the deconvolution method employed was assessed by comparing three data sets obtained by analyses of one, two, and four regions of interest (ROIs), all covering the entire brain area. The accuracy of CT-derived CBF was analyzed for normal (n = 5 studies) and ischemic (n = 7 studies) brain tissue using fluorescent microspheres. Repetitive CT studies were performed to evaluate the precision of the CT measurements. RESULTS The stability of the deconvolution method was high with variabilities of 2.3% (CBV), 5.9% (CBF), and 8.9% (mean transit time), respectively. The correlation between the CT and the microsphere measurements was good for both normal and ischemia studies (r > 0.78, slope > 0.9). The variability of the CT CBF (30.6%) was higher than that of the CT CBV (12.3%) measurements. CONCLUSION Our novel dynamic CT method is stable with respect to the sizes of ROIs used, allowing for accurate measurements of CBV and CBF in both normal and ischemic tissue. Further studies are necessary to evaluate the variability of this method under controlled physiologic conditions.
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Lee TY, Weng TL, Lin CH, Sun YN. Interactive voxel surface rendering in medical applications. Comput Med Imaging Graph 1999; 23:193-200. [PMID: 10551725 DOI: 10.1016/s0895-6111(99)00015-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Semi-boundary (SB) data structure is a compact voxel surface representation of the structure from the medical images. It represents only the boundary of the extracted structure and only an opaque object boundary involved in a 3D dataset can be visualized. Its computational complexity is in proportion to the number of SB voxels. In this paper, we propose schemes to reduce the number of projections in two ways. First, in conjunction with neighboring code, we exploit a set of visibility tables to cull some of the invisible SB voxels. Second, we exploit three pass rotations and an incremental approach to quickly determine the projection position for each SB voxel during rendering. With these two combinations, we significantly improve SB rendering performance. As a result, we can achieve an interactive rendering speed on general purpose workstations for our medical applications.
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Liou JT, Lui PW, Lo YL, Liou L, Wang SS, Yuan HB, Chan KH, Lee TY. Normative data of quantitative thermal and vibratory thresholds in normal subjects in Taiwan: gender and age effect. ZHONGHUA YI XUE ZA ZHI = CHINESE MEDICAL JOURNAL; FREE CHINA ED 1999; 62:431-7. [PMID: 10418177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
BACKGROUND Quantitative sensory testing has gained popularity as a tool in the diagnosis of peripheral neuropathies. This study aims to establish normative data of quantitative thermal and vibratory thresholds in normal subjects in Taiwan. In addition, we also examined the effect of age and gender differences on these thresholds. METHODS The study included 100 healthy subjects (50 males and 50 females) who were admitted for regular physical examination. The quantitative testing of thermal, cold and vibratory sensations were performed having recourse to a Thermotest instrument applied on the right hand and foot of these subjects. Measurements included perception thresholds of warm (WT), cold (CT), heat pain, cold pain and vibration as well as a visual analog pain scale. RESULTS Age was comparable between the sexes, but the male subjects were taller than the female subjects. A higher WT and CT in the hand, but not in the foot, were found in the male subjects in comparison with the female subjects. Heat pain threshold and cold pain threshold of both sites did not significantly differ between genders. Moreover, the groups did not differ in vibration threshold and visual analog pain scale. Young subjects (age < 30 years) showed a higher CT in the foot than the older subjects (age > 50 years). None of the above parameters were different between these two age groups. Overall, the age or height bore no significant relation to the difference between WT and CT (DDWT-CT). CONCLUSIONS The female subjects were found to be more sensitive to warm and cold stimulation in the hand than their counterparts. These results have provided valuable normative data on sensory perceptive thresholds in Taiwanese, which are useful as a tool in the diagnosis of peripheral neuropathy.
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Tsubota K, Kwong KK, Lee TY, Nakamura J, Cheng HM. Functional MRI of brain activation by eye blinking. Exp Eye Res 1999; 69:1-7. [PMID: 10375444 DOI: 10.1006/exer.1999.0660] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Functional magnetic resonance imaging (fMRI) was used to map cortical areas that control eye blinking. T2*-weighted asymmetric spin-echo MRI (or BOLD-blood oxygen level dependent-MRI) was used to detect changes caused by focal variations in blood oxygenation. Six normal volunteers and two cases of dry eye (less than 5-mm Schirmer's test) entered the study. The experimental scheme consisted of three cycles of a two-step sequence: (eyes closed)-(blink or blink inhibition). And to minimize contamination from photic activation, the experiments were carried out in a dark environment and the volunteers reported no light perception during the MR scans. In all eight cases, normal blinking (about one blink every 4 sec) activated areas in the orbitofrontal cortex and in some cases, the visual cortex including the anterior portion of the visual cortex and the primary visual cortex. In severe dry eye, blink-inhibition strongly activated the visual cortex even after irritation due to corneal desiccation was removed by topical anesthesia. The blinking process, especially the rate, appears to be controlled in the orbitofrontal cortex. The significance of visual cortex activation in the dark and in the case of severe dry eye still remains unclear; although it may be associated with attention and arousal.
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Leaw SJ, Cheng YF, Lee YC, Lee TY. Cholangiocarcinoma presenting as lung mass with hemoptysis. ABDOMINAL IMAGING 1999; 24:407-9. [PMID: 10390568 DOI: 10.1007/s002619900525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
A case of peripheral cholangiocarcinoma with the presentation of chronic hemoptysis and lung mass without evident jaundice is reported. Exophytic spread of hepatobiliary disease through the diaphragm through perihepatic ligaments is described as the possible route of invasion of the tumor.
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Ko SF, Wan YL, Ng SH, Lee TY, Cheng YF, Wong HF, Hsieh MJ. MRI of thoracic vascular lesions with emphasis on two-dimensional time-of-flight MR angiography. Br J Radiol 1999; 72:613-20. [PMID: 10560347 DOI: 10.1259/bjr.72.858.10560347] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
MRI is a valuable method for evaluating thoracic vascular lesions by virtue of its non-invasiveness and multiplanar capability. In addition, ionizing radiation and iodinated contrast medium are not required. Electrocardiographically gated T1 weighted spin echo MRI remains the principal technique for demonstrating the anatomy and morphology of thoracic vascular diseases. Cine MRI allows dynamic evaluation of vascular flow, whereas MR angiography is particularly useful in the two-dimensional (2D) or three-dimensional (3D) display of vascular anatomy. This pictorial review illustrates the use of 2D time-of-flight MR angiography in the assessment of various thoracic vascular conditions including aortic arch and great vessel anomalies, heterotaxic syndromes, aortic dissection, aortic or arch vessel aneurysms, pulmonary embolism, pulmonary sequestration, axillofemoral bypass and tumour/vessel relationships.
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148
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Lee TY, Lin PH, Lin CH, Sun YN, Lin XZ. Interactive 3-D virtual colonoscopy system. IEEE TRANSACTIONS ON INFORMATION TECHNOLOGY IN BIOMEDICINE : A PUBLICATION OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY 1999; 3:139-50. [PMID: 10719495 DOI: 10.1109/4233.767089] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We describe a low-cost three-dimensional (3-D) virtual colonoscopy system that is a noninvasive technique for examining the entire colon and can assist physicians in detecting polyps inside the colon. Using the helical CT data and proposed techniques, we can three-dimensionally reconstruct and visualize the inner surface of the colon. We generate high resolution of video views of the colon interior structures as if the viewer's eyes were inside the colon. The physicians can virtually navigate inside the colon in two different modes: interactive and automatic navigation, respectively. For automatic navigation, the flythrough path is determined a priori using the 3-D thinning and two-pass tracking schemes. The whole colon is spatially subdivided into several cells, and only potentially visible cells are taken into account during rendering. To further improve rendering efficiency, potentially visible cells are rendered at different levels of detail. Additionally, a chain of bounding volume in each cell is used to avoid penetrating through the colon during navigation. In comparison with previous work, the proposed system can efficiently accomplish required preprocessing tasks and afford adequate rendering speeds on a low-cost PC system.
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149
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Ho CM, Tsou MY, Sun MS, Chu CC, Lee TY. The optimal effective concentration of lidocaine to reduce pain on injection of propofol. J Clin Anesth 1999; 11:296-300. [PMID: 10470630 DOI: 10.1016/s0952-8180(99)00040-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
STUDY OBJECTIVE To determine the optimal concentration of lidocaine that reduces pain on injection of a propofol-lidocaine mixture. DESIGN Prospective, randomized, double-blinded, clinical investigation. SETTING Medical center, university teaching hospital. PATIENTS 240 ASA physical status I and II female outpatients, aged 21 to 65 years, undergoing dilation and curettage with propofol for anesthesia induction. INTERVENTIONS Patients were randomized to one of four groups in double-blinded fashion. In Group A (control), patients were given propofol containing normal saline; in Group B, Group C, and Group D, patients received propofol containing 0.05% lidocaine (Group B), propofol containing 0.1% lidocaine (Group C), and propofol containing 0.2% lidocaine (Group D) for induction. MEASUREMENTS AND MAIN RESULTS The incidence of pain on injection of propofol was significantly decreased in Group C and Group D (8.3% and 10.0%, respectively) in comparison to the control group (91.7%) (p < 0.001). Although the result in Group B (76.7%) was better than that in the control group, the difference was not statistically significant. No significant difference was seen between Group C and Group D. CONCLUSIONS The optimal effective concentration of lidocaine, which decreased the incidence of pain caused by propofol injection, was 0.1% in the currently studied population.
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150
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Lu CY, Yuan HB, Chang WK, Lui PW, Lee TY. Unexpected transurethral resection of prostate syndrome complicated with acute myocardial infarction during transurethral incision procedure--a case report. ACTA ANAESTHESIOLOGICA SINICA 1999; 37:105-8. [PMID: 10410413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
Transurethral incision (TUI) is a simple and safe procedure. We, herein, present a case undergoing transurethral incision procedure during which he developed transurethral resection of prostate syndrome (TURP syndrome) and hypothermia precipitating an acute perioperative myocardial infarction attack. The potential risk of development of TURP syndrome in settings other than TURP surgery as well as its prevention are reviewed and discussed.
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