Biomedical subjects

Hiroshi Toyoda

Publications and source records attributed to Hiroshi Toyoda.

14 recordsLinked to original sources

PubMed2006

Application of ultrasonography for blunt laryngo-cervical-tracheal injury.

BACKGROUND: Bronchoscopy has been the gold standard for diagnosing blunt laryngo-cervical-tracheal injury (BLCTI); however, BLCTI is often undetected. Ultrasonography (US) is an indispensable tool in the field of critical care and traumatology, but has not been considered useful for evaluation of the airway. The aim of this study was to determine the usefulness of US in the diagnosis of BLCTI. METHODS: To determine the detectability of BLCTI by US, we use a model of cylindrical plastic with a protruding mass made of paste. The model was placed in a water bath and US (3.5-MHz probe) was used to try to detect the mass. RESULTS: We could detect the existence of the mass as a high echoic mass with strongly high echoic tail. We used four patients with BLCTIs whose sites of injury were confirmed by computed tomography (CT) and bronchoscopy. We evaluated the larynx and the cervical trachea as their outline of air in the cranial section near the sternal notch using a 3.5-MHz convex probe. The following US findings were compared with CT and bronchoscopic images as specific findings of BLCTI: discontinuity of the laryngo-cervical-tracheal wall and an abnormal mass protruding into the laryngo-cervical-tracheal lumen. Specific findings of BLCTI were detected in three of the four patients, whose sites of injury were the anterior or lateral side of the larynx or the cervical trachea. The site of injury of the remaining patient, where we detected no specific BLCTI findings, was the posterior wall of the larynx. CONCLUSIONS: US is useful for the diagnosis of BLCTI because it is capable of presenting specific images showing BLCTI features such as discontinuity of the laryngo-cervical-tracheal wall and abnormal masses protruding into the lumen; not only as a single diagnostic tool but one tool with many uses.

Bronchoscopy↗

PubMed2006

Angiomyofibroblastoma of the vulva: a large pedunculated mass formation.

Angiomyofibroblastoma is a rare, usually small benign mesenchymal tumor that occurs in vulvar lesions of premenopausal women. A case of angiomyofibroblastoma that arose as a unique pedunculated and particularly large mass in the left vulva of a 48-year-old woman is presented herein. The patient had been aware of a gradually enlarged mass of 7 years duration without any other gynecological symptoms or signs. The maximum dimension of the tumor measured 11 cm. The resected tumor was well circumscribed with a bulging and glistening cut surface. Histological examination revealed an admixture of irregularly distributed hypercellular and hypocellular areas with spindled, plump spindled, or plasmacytoid stromal cells and abundant venular or capillary-sized vessels. Stromal cells characteristically cluster around delicate vessels within an edematous to collagenous matrix. In the present case, intralesional adipose tissue was present throughout the tumor. There was no significant nuclear atypia, and mitotic figures were very sparse. There was little stromal mucin throughout the tumor. Immunohistochemically, the stromal cells were characterized by strong reactivity for vimentin and CD34, with focal reactivity for desmin and alpha smooth muscle actin. Both estrogen and progesterone receptors were diffusely expressed in the stromal cells. These histological findings are consistent with angiomyofibroblastoma and support the hypothesis that angiomyofibroblastoma originates from perivascular stem cells with a capacity for myofibroblastic and fatty differentiation.

Female↗

PubMed2005

Usefulness of the 3-dimensionally reconstructed computed tomography imaging for diagnosis of the site of tracheal injury (3D-tracheography).

Computed tomography (CT) has not been considered useful for early diagnosis of traumatized patients who could hardly hold their breath, particularly patients with tracheal injuries. However, the recent development of spiral CT has made it possible to acquire contiguous patient data, which eliminates the respiratory misregistration. Air is easily differentiated from surrounding tissues by striking contrast, and the trachea can therefore be well displayed by three-dimensional (3D)-CT. We consider that it is possible to show tracheal injury by 3D-CT. The aim of this study is to clarify the usefulness of 3D-CT for detecting the injury site of blunt tracheal injuries. The study was carried out in hemodynamically stable patients who were suspected of having tracheal injury based on clinical manifestations such as hemoptysis, or cervical subcutaneous, deep cervical, or mediastinal emphysema. Repeated bronchoscopy confirmed tracheal injury. The virtual images of the 3D-CT (3D-tracheography) were compared with the direct images of bronchoscopic findings. Five cases were examined. In patients with tracheal injury, bronchoscopy revealed laceration of the tracheal lumen or disruption and dislocation of the tracheal cartilage, partially coated by mucus and clot, findings that confirmed the diagnosis of tracheal injury. The virtual images of the 3D-tracheography clearly showed the injury as a defect in the tracheal wall or a depression in the wall. The site and size of injury shown in the 3D-tracheography were comparable with those detected by bronchoscopy. We succeeded in detecting tracheal injuries by 3D-CT imaging, the virtual images of which were comparable with the bronchoscopic findings. 3D-tracheography is a useful method for diagnosing the site and form of tracheal injury in hemodynamically stable patients.

Adult↗

PubMed2005

Cardiac functional analysis with multi-detector row CT and segmental reconstruction algorithm: comparison with echocardiography, SPECT, and MR imaging.

PURPOSE: To evaluate accuracy of cardiac functional analysis with multi-detector row computed tomography (CT) and segmental reconstruction algorithm over a range of heart rates. MATERIALS AND METHODS: Institutional review board approval was obtained. Informed consent was not required. Multi-detector row CT (500-msec rotation time, 8 x 1-mm detector collimation) and magnetic resonance (MR) imaging were performed in 50 patients (28 men, 22 women; age range, 46-84 years; mean age, 67 years). Two-dimensional echocardiography was performed in 41 patients, and electrocardiographically (ECG)-gated single photon emission computed tomography (SPECT) was performed in 27. End-diastolic volume (EDV), end-systolic volume (ESV), ejection fraction (EF), and left ventricular (LV) mass were estimated with multi-detector row CT and compared with values estimated with MR imaging, which served as the reference standard. Additionally, EF values estimated with multi-detector row CT, echocardiography, and SPECT were compared with those estimated with MR imaging. Systemic error and degree of agreement of global functional parameters measured with MR imaging and other modalities were assessed. In a second analysis, linear regression analysis was added. RESULTS: EF estimated with multi-detector row CT agreed and correlated well with EF estimated with MR imaging (bias +/- standard deviation, -1.2% +/- 4.6; r = 0.96). Agreement and correlation were similar for EDV (-0.35 mL +/- 15.2; r = 0.97), ESV (1.1 mL +/- 8.6; r = 0.99), and LV mass (2.5 mL +/- 15.0; r = 0.96). Standard deviation of EF difference between multi-detector row CT and MR imaging was significantly less than that between echocardiography and MR imaging (P < .001) or that between SPECT and MR imaging (P < .001). CONCLUSION: Various LV functional parameters were measured with multi-detector row CT with a segmental approach, and measurements correlated and agreed with those obtained with MR imaging. Moreover, functional analysis with multi-detector row CT was more accurate than that with two-dimensional echocardiography or ECG-gated SPECT.

Aged↗

PubMed2004

Effect of caffeine intake on myocardial hyperemic flow induced by adenosine triphosphate and dipyridamole.

UNLABELLED: The aims of this study were (a). to compare absolute myocardial blood flow (MBF) during adenosine triphosphate (ATP) infusion with that after dipyridamole administration without caffeine intake and (b). to evaluate the effect of caffeine intake on the hyperemic flow induced by these coronary vasodilator agents. METHODS: MBF was quantified with (15)O-labeled water and PET at rest, during ATP infusion (0.16 mg/kg/min for 9 min), and after dipyridamole administration (0.56 mg/kg over 4 min) after a 24-h abstinence from caffeine (baseline evaluation) in 10 healthy volunteers. Within 2 wk, the same PET studies were repeated after caffeine intake to evaluate the effect of caffeine on the hyperemic flow induced by these pharmacologic agents (caffeine study). Myocardial flow reserve (MFR), defined as the ratio of hyperemic to resting blood flow, was also evaluated. RESULTS: Resting MBF in baseline and caffeine studies did not differ significantly (0.79 +/- 0.29 vs. 0.75 +/- 0.31 mL/min/g, P = 0.88). Without caffeine intake, MBF during ATP infusion was significantly higher than that after dipyridamole administration (3.70 +/- 0.67 vs. 3.00 +/- 0.79 mL/min/g, P = 0.003), whereas there was no significant difference in MFR between ATP and dipyridamole stress (5.15 +/- 1.64 vs. 4.11 +/- 1.44, P = 0.07). After caffeine intake, the hyperemic flows induced by ATP and dipyridamole were not significantly different (1.68 +/- 0.37 vs. 1.52 +/- 0.40 mL/min/g, P = 0.50). MFR estimated by ATP and dipyridamole also did not differ significantly in the caffeine studies (2.44 +/- 0.88 vs. 2.25 +/- 0.94, P = 0.73). MBF during ATP infusion and after dipyridamole administration were significantly lower in the caffeine studies than that in the baseline evaluation (1.68 +/- 0.37 vs. 3.70 +/- 0.67 mL/min/g, P < 0.0001, and 1.52 +/- 0.40 vs. 3.00 +/- 0.79 mL/min/g, P < 0.0001, respectively). CONCLUSION: This study demonstrates that ATP has the potential to induce greater hyperemia than dipyridamole, whereas hyperemic responses to ATP and dipyridamole are similarly attenuated after caffeine intake. These findings suggest that abstinence from caffeine before ATP stress testing may be needed.

Adenosine Triphosphate↗

PubMed2003

Cortical correlates of vestibulo-ocular reflex modulation: a PET study.

To elucidate cortical correlates of vestibulo-ocular reflex (VOR) modulation, we observed cortical activation during fixation suppression and habituation of caloric vestibular nystagmus in 12 normal subjects, using PET. Significant positive correlation between regional cerebral blood flow (rCBF) and slow phase eye velocity of caloric nystagmus was observed in the middle and posterior insula, inferior parietal lobule, temporal pole, right fusiform gyrus, lingual gyrus, and cerebellar vermis and hemisphere. The rCBF increase in the insular region and the inferior parietal lobule was lateralized depending on the direction of the nystagmus. Caloric nystagmus was suppressed as a result of visual fixation, during which time the area around the right frontal eye field, temporal pole, inferior temporal gyrus, a broad area in the visual cortex, including fusiform and lingual gyrus, cerebellar uvula/nodulus and flocculus, exhibited positive correlation with fixation suppression of caloric nystagmus, while vestibular cortices exhibited negative correlation. The caloric nystagmus habituated with repetition of stimulation. With habituation, we observed activation in the right anterior cingulate gyrus, left superior parietal lobule and right cuneus, and deactivation in the anterior insula, cingulate gyrus, inferior parietal lobule and occipito-temporal visual cortex. The region that showed significant co-activation with fixation suppression and habituation of caloric nystagmus was the right cuneus, and significant co-deactivation was observed in the anterior insula, cingulate gyrus, inferior parietal lobule and middle temporal visual cortex. The present results support previous observations that the parieto-insular cortex and inferior parietal lobule are involved in processing of vestibular information, and, in addition, suggest that activation may depend on the direction of nystagmus. Deactivation of vestibular cortices during visual fixation supports the concept of inhibitory visual-vestibular interaction in the cortex. Significant activation of the cingulate, superior parietal and visual cortices, and cerebellar vermis accompanying reduction of caloric response with repeated stimuli suggests possible involvement of these regions in vestibular habituation. Common activation of the cuneus in visual cortex and deactivation of vestibular and visuo-spatial association cortices by both visual suppression and habituation of VOR suggests that these two mechanisms are not completely independent but may share some cortical and subcortical regions.

Adult↗

PubMed2003

Inner ear hearing loss modulates ipsilateral temporal lobe activation by monaural speech stimuli.

We examined cortical activation by speech in patients with moderate inner ear hearing loss using PET to investigate the response of the language network to insufficient speech input. We made two word lists, well-perceived words and poorly-perceived words, and measured rCBF during monaural presentation of these words. Well-perceived words activated bilateral temporal lobes, bilateral inferior frontal gyri (IFG) and left angular gyrus (AG) regardless of the ear stimulated, Poorly-perceived words activated contralateral temporal lobe and bilateral IFG, while little or no activation was observed in the ipsilateral temporal lobe and left AG. Insufficient activation of the temporal lobe ipsilateral to the ear stimulated might correlated with less accurate word comprehension in patients with inner ear hearing loss.

Acoustic Stimulation↗

PubMed2003

The effect of nitroglycerin on myocardial blood flow in various segments characterized by rest-redistribution thallium SPECT.

UNLABELLED: The use of nitrates is reported to be effective in viability detection in scintigraphic perfusion imaging. The purpose of the study was to evaluate the effect of nitroglycerin (NTG) on myocardial blood flow (MBF) and coronary vascular resistance (CVR) in various segments characterized by rest-redistribution (201)Tl SPECT. METHODS: Twenty-three patients with coronary artery disease underwent rest-redistribution (201)Tl SPECT and (15)O-labeled water PET at rest and after NTG spray (0.3 mg). In addition, 11 healthy volunteers were also studied using PET. RESULTS: NTG did not change global MBF in the volunteers or in the patients. In segments with normal (201)Tl uptake and in those with a severe irreversible (201)Tl defect, NTG significantly reduced MBF without changing CVR. NTG reduced CVR in segments with a reversible (201)Tl defect (141 +/- 50 to 114 +/- 29 mm Hg/[mL/min/g], P = 0.004) and in those with a mild-to-moderate irreversible (201)Tl defect (165 +/- 64 to 149 +/- 60 mm Hg/[mL/min/g], P = 0.003), while maintaining MBF. CONCLUSION: NTG preferentially reduces CVR in the viable myocardium with ischemia. After NTG, tracer uptake in the ischemic myocardium will be relatively increased compared with that in the nonviable and nonischemic myocardium, leading to improvements in viability detection.

Aged↗

PubMed2003

Relationship between vasodilatation and cerebral blood flow increase in impaired hemodynamics: a PET study with the acetazolamide test in cerebrovascular disease.

UNLABELLED: The changes in cerebral blood flow (CBF) and arterial-to-capillary blood volume (V(0)) induced by acetazolamide (ACZ) are expected to be parallel each other in the normal circulation; however, it has not been proven that the same changes in those parameters are observed in patients with cerebrovascular disease. To investigate the relationship between changes in CBF, vasodilatory capacity, and other hemodynamic parameters, the ACZ test was performed after an (15)O-gas PET study. METHODS: Twenty-two patients with unilateral major cerebral arterial occlusive disease underwent PET scans using the H(2)(15)O bolus method with the ACZ test after the (15)O-gas steady-state method. CBF and V(0) for each subject were calculated using the 3-weighted integral method as well as the nonlinear least-squares fitting method. After evaluation of accuracy in V(0) values, a new parameter, the CBF/V(0) ratio, which is expected to disclose arterial perfusion pressure, was also compared between the conditions. RESULTS: The regional CBF (rCBF) and V(0) increased significantly after ACZ administration in the hemisphere contralateral to the ischemic side. However, in a subgroup of patients who showed a significant reduction in the rCBF increase in the ipsilateral hemisphere (group A), the ACZ injection caused no change or a slight decrease in rCBF even though the V(0) showed a significant increase. Thus, the increases in rCBF and V(0) did not necessarily parallel each other in the ipsilateral hemispheres of patients who have impaired cerebral circulation. A parameter defined by the rCBF/V(0) ratio decreased significantly in the ipsilateral hemisphere of group A after ACZ administration, although the ratio showed no change in the contralateral hemisphere or in the other subgroup (group B). CONCLUSION: The change in the rCBF/V(0) ratio after ACZ challenge may represent an alteration in arterial perfusion pressure that is expected to indicate a critical hemodynamic status in patients with cerebrovascular disease, especially in patients who have a reduced rCBF response.

Acetazolamide↗

PubMed2002

MR imaging with quantitative diffusion mapping of tacrolimus-induced neurotoxicity in organ transplant patients.

Our objective was to investigate brain MR imaging findings and the utility of diffusion-weighted (DW) imaging in organ transplant patients who developed neurologic symptoms during tacrolimus therapy. Brain MR studies, including DW imaging, were prospectively performed in 14 organ transplant patients receiving tacrolimus who developed neurologic complications. In each patient who had abnormalities on the initial MR study, a follow-up MR study was performed 1 month later. Apparent diffusion coefficient (ADC) values on the initial MR study were correlated with reversibility of the lesions. Of the 14 patients, 5 (35.7%) had white matter abnormalities, 1 (7.1%) had putaminal hemorrhage, and 8 (57.1%) had normal findings on initial MR images. Among the 5 patients with white matter abnormalities, 4 patients (80.0%) showed higher than normal ADC values on initial MR images, and all showed complete resolution on follow-up images. The remaining 1 patient (20.0%) showed lower than normal ADC value and showed incomplete resolution with cortical laminar necrosis. Diffusion-weighted imaging may be useful in predicting the outcomes of the lesions of tacrolimus-induced neurotoxicity.

Adult↗

PubMed2002

A simplified double-injection method to quantify cerebral blood flow and vascular reserve using iodine-123 IMP-SPECT.

UNLABELLED: We developed and evaluated a simplified double-injection method for iodine-123 N-isopropyl-p-iodoamphetamine (IMP) to quantify regional cerebral blood flow (rCBF) twice in a single SPECT session. The method enabled rapid calculations of rCBF with five 10-minute SPECT scans, a fixed distribution volume (Vd), and one-point arterial blood sampling to calibrate a standard input function (SIF). METHODS: Sixty neurological patients were examined to measure rCBF twice in a single session of IMP-SPECT. Patients underwent frequent arterial blood sampling with two injections of IMP and acetazolamide challenge. We generated the SIF and determined the optimal Vd and calibration time (t(cal)) for the SIF in 30 patients. Validities of the fixed t(cal) and Vd were assessed in the remaining 30 patients. Simulation studies were also performed to evaluate the error sensitivity of the method. RESULTS: The optimal t(cal) and Vd were 34 min and 30 ml/ml, respectively. The method was robust in rCBF calculation with noisy SPECT data and yielded rCBF with negligible bias and acceptable errors compared with those obtained by the double-injection method previously reported. CONCLUSION: The method can be applied to measure rCBF twice in a single SPECT session more easily and less invasively.

Aged↗

PubMedDate not supplied

Oxygen metabolism of the liver during an HA clamp: HV saturation and free radicals.

BACKGROUND/AIMS: To clarify changes in the hepatic oxygen metabolism and tissue damage resulting from oxygen-derived free radical generation from polymorphonuclear cells during a hepatic arterial clamp. METHODOLOGY: Subjects were 32 male Wistar rats. Hepatic tissue blood flow, and hepatic venous chemiluminescence, indicating oxygen-derived free radicals from polymorphonuclear cells, and liver lipid peroxide were measured, and hepatic and portal venous blood gas analysis were performed before and after 130 minutes of hepatic arterial clamping. RESULTS: Hepatic tissue blood flow decreased by hepatic arterial clamp. The values of hepatic arterial oxygen pressure (HTBF), hepatic venous oxygen saturation (ShvO2), and O2 contents after hepatic arterial clamp were lower than those before hepatic arterial clamp (P = 0.035, 0.024, and 0.028, respectively). Hepatic venous chemiluminescence decreased and the lipid peroxide level of the liver increased by hepatic arterial clamp (P = 0.001). CONCLUSIONS: ShvO2 is useful for the evaluation of hepatic oxygen metabolism and hepatic tissue blood flow during acute hepatic arterial clamp. This condition should prepare the following tissue damage due to oxygen-derived free radicals from polymorphonuclear cells.

Animals↗

PubMedDate not supplied

Monitoring and evaluation of intraperitoneal bleeding (IPB) by small portable ultrasonography during transcatheter arterial embolization (TAE) in abdominal-pelvic trauma patients with shock: as a monitor for early detection of increase of IPB.

BACKGROUND/AIMS: Blunt abdominal-pelvic trauma patients with shock often require transcatheter arterial embolization (TAE), and may also require surgery if intraperitoneal bleeding (IPB) becomes massive. Deciding whether the patient should undergo surgery is highly critical. We sometimes perform TAE without attention to IPB because it has been difficult to evaluate the volume of IPB exactly during TAE. Currently we use small portable ultrasonography (PUS) as a monitor of volume of IPB during TAE. The aim of this study is to clarify the usefulness of PUS for monitoring changes in IPB during TAE. METHODOLOGY: We examined the volume of IPB by PUS during TAE without disturbing the operators of TAE. In our protocol, if the volume of IPB showed rapid increase we tried to perform a surgical procedure. The design of this study was a prospective case series study. RESULTS: We examined 26 patients. Increase of IPB was detected in 3 cases; two were undergoing angiography for ileac and renal arteries when PUS indicated increase of IPB, which drew attention to their hepatic arteries. The other was examined initially for internal ileac artery and underwent surgery because of an increase of IPB. In the other 22 cases, we confirmed no increment of IPB by PUS and continued the procedure. CONCLUSIONS: PUS is useful for deciding the order of therapeutic procedure, and is a useful monitoring instrument for increase of IPB.

Abdominal Injuries↗

PubMedDate not supplied

Gastrointestinal fiberscopic findings after simple closure for perforated duodenal ulcer in the early postoperative phase: from experience to evidence by evaluation of the healing process.

BACKGROUND/AIMS: Today, in light of widespread adoption of H2-RA and PPI, the standard surgical procedure for perforated duodenal ulcer (PDU) is simple closure and/or omental patch (SC). However, the healing process after these techniques has not been fully examined. We have not yet confirmed the propriety of simple suture of the bottom of the ulcer. This technique has been performed based only on experience, and there is insufficient evidence to conclude that this procedure can be definitively considered a safe therapeutic technique for the majority of patients with PDU. The aim of this study is to clarify the macroscopic findings of the healing process after SC for PDU. METHODOLOGY: Thirteen patients with PDU who were treated with SC underwent postoperative gastroduodenal fiberscopy (GF) at the 7th-16th postoperative day and the healing process was monitored under sufficient informed consent. Patients with severe preoperative disease were excluded from the study. Healing condition of the ulcer and stitches, deformity, and stenosis were evaluated by postoperative endoscopy. Possible adverse effects that were evaluated included: perforation, rise in fever, worsening of inflammation on laboratory data, gastrointestinal symptoms such as abdominal pain, sense of fullness, and vomiting. The indications for SC were as follows: PDU with 1) no stenosis and 2) no prominent ulcer ridge. The surgical technique was as follows: 1) interrupted simple closure with no trimming and debridement of wound (4-5 stitches) with absorbable monofilament suture, and/or 2) omental patch, 3) administration of H2-RA (or PPI) just after operation, and 4) oral feeding 4-5 days after operation independent of postoperative GF. RESULTS: GF findings in 2 patients showed active and healing stage, in whom surgical technique was thought to be insufficient; the ulcer had been large and included a descending portion, or a small perforation had occurred in the large ulcer bottom (the distance between the stitches and the edge of the ulcer was insufficient). In the other 11 patients, GF findings showed scar phase. There was no morbidity related to endoscopic procedure. CONCLUSIONS: Sutured PDU with SC will be in the scar phase in 1 or 2 weeks. Postoperative GF 1 week after SC for PDU is thought to be a safe examination. This study is a primitive study of a small group, and more cases that can adequately show the frequency of complications and indicate the overall safety of the procedure are needed.

Adolescent↗