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Katsuhiko Kato

Publications and source records attributed to Katsuhiko Kato.

At least 19 recordsLinked to original sources
PubMed2006

Micturition induced seizures: ictal EEG and subtraction ictal SPECT findings.

We report an 8-year-old girl with seizures induced by micturition. Her seizures were characterized by extension of upper extremities with preserved consciousness. Magnetic resonance imaging and interictal electroencephalograms were normal. Ictal electroencephalogram showed low voltage fast waves without clear focal features followed by frontal dominant rhythmic multiple spikes. Subtraction ictal single photon emission computed tomography revealed a significant increase in blood flow in the mesial frontal area.

Child↗
PubMed2006

Single photon emission computed tomography and serial MRI in preterm infants with kernicterus.

Single photon emission computed tomography was performed in three preterm infants with athetoid cerebral palsy due to kernicterus. No clinical signs and symptoms of kernicterus, or ultrasonographic abnormalities were seen during the neonatal period in any patients. Although MRI during infancy revealed high intensity areas in bilateral globi pallidi in all of them, MRI abnormalities were mild in two of them. On later MRI, subtle high intensity areas in the globi pallidi were recognized in only one of them. Single photon emission computed tomography demonstrated hypoperfusion in the basal ganglia regions in all patients. Regions of interest analyses showed decreased blood flow in the basal ganglia related to the cortical areas. Single photon emission computed tomography will be useful for the diagnosis of kernicterus, whereas MRI abnormalities become less clear beyond infancy.

Basal Ganglia↗
PubMed2006

Cerebral glucose metabolism change in patients with complex regional pain syndrome: a PET study.

PURPOSE: The aim of this study was to examine abnormalities of the central nervous system in patients with chronic pain who were diagnosed with complex regional pain syndrome (CRPS). MATERIALS AND METHODS: Brain activity was assessed using (18)F-fluorodeoxyglucose positron emission tomography. The data collected from 18 patients were compared with data obtained from 13 normal age-matched controls. RESULTS: Our results showed that glucose metabolism was bilaterally increased in the secondary somatosensory cortex, mid-anterior cingulated cortex (ACC) or posterior cingulated cortex (PCC) (or both), parietal cortex, posterior parietal cortex (PPC), and cerebellum as well as in the right posterior insula and right thalamus in our patients. In contrast, glucose metabolism was reduced contralaterally in the dorsal prefrontal cortex and primary motor cortex. Glucose metabolism was bilaterally elevated in the mid-ACC/PCC and the PPC, which correlated with pain duration. CONCLUSION: These data suggested that glucose metabolism in the brains of patients with CRPS changes dramatically at each location. In particular, glucose metabolism was increased in the areas concerned with somatosensory perception, possibly due to continuous painful stimulation.

Adult↗
PubMed2006

Low efficacy of 18F-FDG PET for detection of uveal malignant melanoma compared with 123I-IMP SPECT.

UNLABELLED: Earlier investigations showed that N-isopropyl-p-123I-iodoamphetamine SPECT (123I-IMP SPECT) is useful for the diagnosis of uveal malignant melanoma, whereas the feasibility and usefulness of 18F-FDG PET in uveal malignant melanoma have not yet been established. We compared the usefulness of 123I-IMP SPECT and 18F-FDG PET for the detection of uveal malignant melanoma on the same subjects. METHODS: Nineteen patients (10 men, 9 women) with suspected uveal malignant melanoma were examined by 123I-IMP SPECT. Thirteen of them were also examined by 18F-FDG PET. 123I-IMP SPECT was performed at 15 min or at 3 and 24 h after intravenous administration of 123I-IMP. RESULTS: In 12 of 19 study patients, 123I-IMP SPECT obtained at 24 h after intravenous administration of 123I-IMP delineated an area of increased uptake in the site corresponding to the ocular tumor. All of the ocular tumors in the 12 123I-IMP SPECT-positive patients were confirmed histopathologically and clinically to be uveal malignant melanoma. The other 7 123I-IMP-SPECT-negative patients have been monitored under the diagnosis of choroidal nevus, choroidal hemangioma, hyperplasia of the pigment epithelium of the retina, or idiopathic inflammatory lesions without any complications. In a total of 13 patients examined by 18F-FDG PET, 9 of whom were 123I-IMP SPECT positive and 4 were negative, only 1 patient showed abnormal uptake of 18F-FDG PET in the site corresponding to the ocular tumor. Therefore, 8 of 9 patients with uveal malignant melanoma showed false-negative results in 18F-FDG PET. The 18F-FDG PET-positive patient with uveal malignant melanoma had the largest tumor mass with a short diameter of 12 mm, a long diameter of 17 mm, and a height of 7 mm. In the other 8 18F-FDG PET-negative patients, the tumors had a dimension of 11 x 13 x 7 mm or less. CONCLUSION: 123I-IMP SPECT is a sensitive and accurate method for the detection of uveal malignant melanoma, whereas the efficacy of 18F-FDG PET for this purpose is low because of a high incidence of false-negative results. 123I-IMP SPECT is far more superior in comparison with 18F-FDG PET in detecting uveal malignant melanoma.

Adult↗
PubMed2006

Intra- and interobserver agreement and performance score of breast phantom image interpretation: influence of ambient room lighting levels.

The influence of ambient room lighting conditions on soft-copy breast phantom image interpretation was evaluated by comparing cathode ray tube (CRT) monitors with liquid crystal displays (LCDs). Nine observers were asked to use a three-point scale to rate the visibility of various phantom objects (masses, specks, and fibers) displayed on a 21-inch CRT (2,560 x 2,048) and a 21-inch LCD (2,560 x 2,048) under three different levels of ambient lighting (20, 100 and 420 lux at the display center). Each phantom image was interpreted twice, and the reproducibility of judgment and inter-observer agreement was evaluated using kappa statistics. Except for the "mass" score, the LCD score showed a significantly higher value (p<0.05) compared with that of CRT. Nevertheless, no significant differences were found among the three lighting levels. Furthermore, intra- and inter-observer agreement in judgments showed no effects of room illumination. Although the breast phantom objects were better visualized on LCDs than on CRT monitors, room illumination did not affect the performance score of soft-copy reading.

Breast Neoplasms↗
PubMed2005

Cardiac sympathetic dysfunction correlates with abnormal myocardial contractile reserve in dilated cardiomyopathy patients.

OBJECTIVES: We investigated the relationship between iodine-123-metaiodobenzylguanidine (123I-MIBG) findings and myocardial contractile reserve in patients with mild to moderate dilated cardiomyopathy (DCM). BACKGROUND: Little is known regarding the relationship between cardiac sympathetic nervous function and myocardial contractile reserve in DCM. METHODS: Twenty-four DCM patients who showed sinus rhythm underwent echocardiography, biventricular catheterization, and myocardial 123I-MIBG scintigraphy. Left ventricular (LV) pressures were measured using a micromanometer-tipped catheter. The myocardial contractile function (LV dP/dt(max)) was determined at rest and during atrial pacing. The messenger ribonucleic acid (mRNA) expressions of intracellular Ca2+-regulatory proteins were analyzed by real-time quantitative reverse transcription-polymerase chain reaction. Myocardial 123I-MIBG accumulation was quantified as a heart-mediastinum ratio (HMR). RESULTS: A significant correlation was observed between the delayed 123I-MIBG HMR and the percentage change in LV dP/dt(max) from the baseline to the peak or critical heart rate (r = 0.64; p < 0.001). The delayed 123I-MIBG HMR was significantly lower in patients showing a worsening change in LV dP/dt(max) than in those showing a favorable change (p < 0.005). The maximum LV dP/dt(max) during pacing and the sarcoplasmic reticulum Ca2+-ATPase (SERCA2) mRNA levels were significantly more reduced in patients with a delayed HMR < or =1.8 than in those with a delayed HMR >1.8 (p < 0.05, respectively). CONCLUSIONS: Abnormal myocardial 123I-MIBG accumulation is related to an impaired myocardial contractile reserve and down-regulation of SERCA2 mRNA in DCM. Myocardial 123I-MIBG scintigraphy can be useful in noninvasively evaluating myocardial contractile reserve in patients with mild to moderate DCM.

3-Iodobenzylguanidine↗
PubMed2005

Effects of monitor luminance change on observer detection performance.

To confirm that the dimming luminance change in the CRT monitor will have a detrimental effect on diagnostic performance, we performed the four-alternative forced choice experiments on the CRT monitor with the 11 luminance conditions simulating CRT degraded by long-term usage. Six radiologists and one pulmonary physician performed a detection task for 11,000 test areas on 110 test images. The 11 monitor conditions significantly affected the correct detection rates of simulated nodules in the four-alternative forced choice experiments. The gradual deterioration in CRT monitor luminance will have certainly a detrimental effect on detection performance.

Computer Terminals↗
PubMed2005

Cardiac 123I-MIBG reflects left ventricular functional reserve in patients with nonobstructive hypertrophic cardiomyopathy.

UNLABELLED: Little is known about the relation between left ventricular (LV) functional reserve in response to exercise and cardiac sympathetic nervous function in patients with nonobstructive hypertrophic cardiomyopathy (HCM). We investigated whether an assessment of cardiac sympathetic nervous function by myocardial (123)I-metaiodobenzylguanidine ((123)I-MIBG) scintigraphy might provide a sign of an abnormal LV functional reserve in response to exercise-induced beta-adrenergic stimulation in patients with HCM. METHODS: Thirty HCM patients underwent (123)I-MIBG scintigraphy and echocardiography at rest and subsequent biventricular cardiac catheterization at rest and during dynamic exercise. LV pressures were measured using a micromanometer-tipped catheter system. The early and delayed (123)I-MIBG images were quantified as a heart-to-mediastinum ratio (H/M). The plasma levels of brain natriuretic peptide (BNP) and norepinephrine (NE) were also measured. RESULTS: Patients were divided into 2 groups according to the delayed (123)I-MIBG H/M: group I consisted of 12 patients with a delayed H/M of < or =1.8 and group II had 18 patients with a delayed H/M of >1.8. Both the percentage increase from rest to exercise in LV isovolumic contraction (LV dP/dt(max)) and the percentage shortening of LV pressure half-time (T(1/2)) as an index of isovolumic relaxation were significantly less in group I than in group II (P < 0.05, respectively). A significant linear correlation was observed between the percentage increase in LV dP/dt(max) and (123)I-MIBG H/Ms (early H/M: r = 0.49, P < 0.01; delayed H/M: r = 0.54, P < 0.005, respectively). A significant linear correlation was also observed between the percentage shortening in T(1/2) and (123)I-MIBG H/Ms (early H/M: r = 0.58, P < 0.001; delayed H/M: r = 0.64, P < 0.0005, respectively). The plasma NE levels were significantly higher in group I than in group II (P < 0.01), whereas the plasma BNP levels were comparable in the 2 HCM groups. CONCLUSION: beta-Adrenergic enhancement of LV function during exercise may depend on the extent of cardiac sympathetic nervous innervation in HCM patients. Resting myocardial (123)I-MIBG scintigraphy can noninvasively evaluate LV functional reserve in response to exercise in patients with nonobstructive HCM.

3-Iodobenzylguanidine↗
PubMed2004

Time course of lens capsule staining using trypan blue and indocyanine green: in vitro study in porcine eyes.

PURPOSE: To determine whether staining of the lens capsule with trypan blue 0.1% and indocyanine green (ICG) 0.5% diminishes with time and whether it differs between the anterior and posterior capsules. SETTING: Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan. METHODS: Crystalline lenses removed from porcine eyes were stained for 10 seconds with 0.1 mL of trypan blue 0.1% or indocyanine green 0.5%. They were then placed in distilled water and observed for the persistence of staining over time. In a second experiment, the anterior chamber and internal aspects of the anterior capsule and internal and vitreous aspects of the posterior capsule were gently irrigated with 0.1 mL of trypan blue 0.1% or ICG 0.5%. After 10 seconds, the capsules were irrigated with distilled water and the staining intensities were compared. RESULTS: Staining was not diminished 30 seconds, 5 minutes, or 1 hour after application of either dye. No difference was evident in staining intensity or diminution with time between the anterior and posterior capsules, but the external aspects were stained more than the internal aspects with both dyes. Trypan blue produced more intense staining than ICG. CONCLUSIONS: Since the intensity of capsule staining in the intact lens did not change during a 1-hour immersion in water, capsule dyes may not dissipate fully during cataract surgery. As possible long-term adverse effects have not been ruled out, capsule dyes should be used in a low concentration for a short exposure time.

Animals↗
PubMed2004

Diffusion tensor imaging in frontal lobe epilepsy.

We report a 13-year-old female with refractory frontal lobe epilepsy in whom diffusion tensor imaging was useful for exploring subtle cortical malformation. She had frequent simple partial seizures characterized by clonic movement of the right upper extremity. Conventional magnetic resonance imaging was not conclusive. A diffusion tensor imaging revealed an increased apparent diffusion coefficient and reduced anisotropy in the left frontal lobe. Positron emission tomography disclosed hypermetabolism in the adjacent area. We could identify the relatively thick cortex with an indistinct gray-white matter junction in a thin-slice T(1)-weighted image.

Adolescent↗
PubMed2004

Natural vanadium-containing Mt. Fuji ground water improves hypo-activity of liver insulin receptor in Goto-Kakisaki rats.

After daily treatments with Mt. Fuji ground water containing natural vanadium (approximately 65 microg/l) at doses of 0.53 microg/kg/day for 12 weeks, blood glucose (BG), serum hemoglobin A1C (HbA1C) levels and insulin secretion from the pancreas of Goto-Kakisaki (GK) rats, a genetic model of Type 2 diabetes, were improved. In GK rat liver insulin receptors, the binding properties of [125I] insulin, and the activities of insulin receptor beta subunit and primary insulin-like growth factor-1beta all recovered to normal levels of those found in Wistar rats. These results suggest that daily treatment with small concentrations of natural vanadium improves hyperglycemia by ameliorating liver insulin receptor activity.

Administration, Oral↗
PubMed2003

Collection of MNCs and progenitor cells by two separators for PBPC transplantation: a randomized crossover trial.

BACKGROUND: Efficient collection of progenitor cells is essential for PBPC transplantation. Two apheresis machines (Amicus, Baxter Healthcare; and Spectra, Gambro BCT, software version 4.7) were compared prospectively by a crossover trial. STUDY DESIGN AND METHODS: Apheresis collections were performed for two consecutive days on patients for autologous and donors for allogeneic PBPC transplantation. The patients and donors, receiving a G-CSF, were randomized into two groups. In Group I, PBPCs were collected by the Amicus on the 1st day and the Spectra on the 2nd day, and the reverse order was used with Group II. A total of 60 apheresis procedures of 30 (16 in Group I and 14 in Group II) among 40 patients and donors enrolled were performed and evaluated. RESULTS: The nucleated cell counts, MNC counts, CD34+ PBPC counts, and amounts of CFU-GM collected per procedure were similar with the Amicus and the Spectra. On the other hand, the decrease of peripheral blood platelet counts of patients and donors was more prominent from using Spectra than Amicus (p < 0.0001). Components collected by the Amicus had fewer platelets than those collected by the Spectra (p < 0.0001). The efficiencies of collecting nucleated cells, MNCs, and CD34+ PBPCs were not different between the machines (p > 0.05). However, the efficiency of collecting platelets was significantly higher with Spectra than with Amicus (p < 0.0001). The Amicus took longer than the Spectra to process the same volume (p < 0.05). CONCLUSION: Amicus is superior to Spectra in avoiding apheresis-induced thrombocytopenia caused by platelets contaminating the collected samples. Therefore, the Amicus is useful for patients with thrombocytopenia or with a less-than-normal platelet count.

Adolescent↗
PubMed2003

Influence of monitor luminance change on observer performance for detection of abnormalities depicted on chest radiographs.

RATIONALE AND OBJECTIVES: To investigate how changes in luminance affect the detection accuracy of radiologists viewing chest radiograph images on high-resolution CRT monitors. MATERIALS AND METHODS: Thirteen radiologists performed a detection task for 11 chest radiograph images with simulated nodules on a monitor with 11 luminance conditions (the maximum luminance ranges from 157.4-369.0 candela/m2) simulating CRT degraded by long-term usage, under the ambient illumination of 200 lux; the observation order was always from the darkest to the brightest. RESULTS: There was a statistically reliable effect of the 11 monitor display conditions on the detection of nodules (P < 0.001). In the conditions in which the maximum luminance of the CRT was 60.7% or below that of the standard display luminance, the correctly detected nodule number reliably deteriorated. CONCLUSIONS: The luminance change in CRT monitor display under long-term usage will have a detrimental effect on nodule detection performance in chest radiograph images.

Data Display↗
PubMed2003

Prenatal diagnosis for placental steroid salfatase deficiency with fluorescence in situ hybridization: a case of X-linked ichthyosis.

X-linked ichthyosis (XLI) is a relatively common genetic disorder that occurs in about one in every 2000-6000 male births. Clinically, XLI is characterized by a generalized scaling of the skin, with large, polygonal, dark brown scale, and more prominent on the extensor aspects of the limbs. It is known that an undetectable maternal serum, unconjugated estriol, associated with placental steroid sulfatase (STS) deficiency, may be the cause of cause of XLI. In most case, STS deficiency is caused by a complete or partial deletion of the STS gene mapped on chromosome Xp22.3. We describe here the prenatal detection of a male fetus affected with STS deficiency as a result of an undetectable unconjugated estriol in the second-trimester maternal serum screening. Microdeletion of the STS gene was confirmed by fluorescence in situ hybridization analysis of cultured amniotic fluid.

Adult↗
PubMed2003

Quantitative analysis for assessing regional function of liver by using 99mTc-GSA SPECT.

In the present study, we developed quantitative index for evaluating regional liver function using 99mTc diethylenetriamine-pentaacetic acid galactosyl human serum albumin (GSA). A three head SPECT equipped with a low energy high resolution parallel hole collimator was used. Used pre-filter was Butterworth and axial images were reconstructed by a ramp filter without attenuation correction. Correlation between SPECT counts and net concentration of activity of radioisotopes was evaluated in basic consideration using LKS and Nine-Ball phantoms. SPECT Counts = 0.6 x RI concentration. There was a simple correlation among GSA receptor amounts (Cr), injected GSA amounts (S), free GSA amounts (Cf), and intra hepatic receptor ratio ((Cr ratio)). Cr = S - Cf. (Cr ratio) = Cr/S, 0 < (Cr ratio) < 1. Injected GSA amounts can be calculated from injected net RI counts. Free GSA amounts can be evaluated from counts of the heart. GSA receptor amounts can be assumed by performing SPECT three times in series. Regional GSA receptor amounts can be evaluated from the ratio between the region's counts and whole counts. In clinical SPECT images, we could evaluate the regional GSA receptor amounts before and after chemolipiodolization. In conclusion, our method is a simple quantitative index of analyzing regional GSA receptor amounts.

Humans↗
PubMed2003

Relationship between exercise-induced myocardial ischemia and reduced left ventricular distensibility in patients with nonobstructive hypertrophic cardiomyopathy.

UNLABELLED: Many studies have demonstrated that reduced left ventricular (LV) diastolic distensibility plays a key role in the pathophysiology of hypertrophic cardiomyopathy (HCM). However, the relationship between myocardial ischemia and reduced LV distensibility in HCM remains unclear. We aimed to clarify the relationship between exercise-induced ischemia and reduced LV distensibility in patients with HCM. METHODS: Twenty patients with HCM and 5 age-matched control subjects underwent stress-redistribution (201)Tl myocardial scintigraphy and biventricular cardiac catheterization and echocardiography at rest and during exercise. Scintigraphic defect analysis was interpreted using Berman's 20-segment model. The summed stress score (SSS) was calculated as the sum of scores of the 20 LV segments and the summed difference score (SDS) was calculated as the sum of differences between each of the 20 LV segments on stress and rest images. RESULTS: Patients were divided into 2 groups according to the (201)Tl defect as follows: 9 patients with an SSS on (201)Tl of >or=10 and an SDS on (201)Tl of >or=5 (ischemic group) and 11 patients with an SSS of <10 or an SDS of <5 (nonischemic group). The absolute increases from rest to peak exercise in LV end-diastolic pressure (LVEDP) and pulmonary artery wedge pressure were significantly greater (15.5 +/- 5.2 vs. 7.6 +/- 5.5 mm Hg and 17.3 +/- 5.0 vs. 8.9 +/- 5.0 mm Hg, P < 0.01, respectively), and the percentage changes from rest to peak exercise in the maximum first derivative of LV pressure and LV pressure half-time were significantly smaller in the ischemic HCM group compared with the nonischemic HCM group (70% +/- 24% vs. 123% +/- 43% and -32% +/- 6.4% vs. -44% +/- 9.4%, P < 0.01, respectively). However, the end-diastolic dimensions did not differ between the 2 HCM groups. One of the 9 patients in the ischemic group, as revealed by fill-in on (201)Tl scintigraphy, showed increased (18)F-FDG uptake in the anteroseptal wall. CONCLUSION: Some HCM patients show a significant increase in LVEDP without chamber dilatation, indicating reduced LV diastolic distensibility. Myocardial ischemia may at least in part contribute to this condition.

Adult↗
PubMed2002

Elschnig pearl formation along the neodymium:YAG laser posterior capsulotomy margin. Long-term follow-up.

PURPOSE: To examine the long-term occurrence and course of Elschnig pearl (string of pearls) formation along neodymium:YAG (Nd:YAG) laser posterior capsulotomy margins. SETTING: Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan. METHODS: The clinical records of eyes having an Nd:YAG posterior capsulotomy to treat posterior capsule opacification after cataract surgery were retrospectively reviewed. Kaplan-Meier and Cox proportional hazards analysis were performed. RESULTS: Among 201 eyes, string of pearls developed in 139 (69.2%). The mean follow-up after the Nd:YAG posterior capsulotomy was 32.1 months +/- 25.3 (SD). At 2 years, the cumulative probability of developing string of pearls was 77.0% (95% confidence interval [CI], 70.6%-83.4%), after which it reached a plateau. Among the 139 eyes, 100 had sufficient data to be reviewed to assess the long-term outcome (mean follow-up from Nd:YAG posterior capsulotomy, 43.7 +/- 26.0 months). A second Nd:YAG posterior capsulotomy was performed in 18 eyes (18.0%) to treat progression of string of pearls, typically within 2 years after the initial Nd:YAG capsulotomy. The string of pearls disappeared spontaneously in 31 eyes (31.0%). The probability of disappearance was 80.4% (95% CI, 63.4%-97.4%) 8 years after the Nd:YAG posterior capsulotomy. Cox proportional hazards analysis identified no factor significantly favoring the disappearance of the string of pearls. CONCLUSIONS: String of pearls was a common complication after Nd:YAG laser posterior capsulotomy. About 20% of cases were progressive and required a second capsulotomy; however, most regressed over several years.

Cataract↗