Search PubMed⌕ Search

Biomedical subjects

Y Takehara

Publications and source records attributed to Y Takehara.

143 records · Page 8Linked to original sources
PubMed1975

Natural and experimental infections of Japanese tree sparrows with Japanese encephalitis virus.

20 to 37 per cent of wild Japanese tree sparrows had neutralizing antibodies to Japanese encephalitis virus (JEV). Sparrows free of antibodies were inoculated with 10,000 plaque-forming units of JEV. None of the birds became clinically ill. Virus could be detected in blood plasma during the first 3 days after inoculation but not thereafter. Neutralizing antibodies started to appear at 4 days after inoculation and the response was of variable duration, in some cases extending up to 200 days after inoculation.

Animals↗
PubMedDate not supplied

Can MRCP replace ERCP?

Magnetic resonance cholangiopancreatography (MRCP) has replaced direct cholangiography and pancreatography in many instances. Its complete noninvasiveness and flexibility are less onerous for patients. For the use of screening as well as scrutiny, MRCP has played an important role in diagnosing various pathologies in this field. The usefulness of MRCP is not limited to anatomical evaluations; it can also yield physiologic and functional information. From a cost-performance basis, MRCP is undoubtedly superior to direct methods. Coupled with a cutting-edge MR system, MRCP has the potential to limit the use of invasive transpapillary and percutaneous methods merely to interventional purposes. In the near future, the emergence of interventional MR scanners will make MRCP even more competitive, and the replacement will be accelerated.

Cholangiopancreatography, Endoscopic Retrograde↗
PubMedDate not supplied

Macrocystic serous cystadenoma of the pancreas: case report.

We report a case of macrocystic serous cystadenoma of the pancreas. The lesion consisted of a large main cyst and several small cysts, and each cyst showed high intensity on T1-weighted and very high intensity on T2-weighted magnetic resonance images. High-intensity cyst contents may be a characteristic, if not a specific, finding of macrocystic serous cystadenoma of the pancreas.

Cystadenoma, Serous↗
PubMedDate not supplied

MRI of postoperative maxillary cysts.

OBJECTIVE: The purpose of this study is to review the MR characteristics of postoperative maxillary cysts (POMC). MATERIALS AND METHODS: The MR findings in 24 patients with 38 surgically confirmed POMC were retrospectively reviewed. RESULTS: Of 32 cysts detected by MRI, 31 cysts (96.9%) were well demarcated. Nineteen cysts (59.4%) were smooth and the others (40.6%) were irregular. Thirty cysts (93.8%) had signal intensities ranging from that of muscle to that of subcutaneous fat on T1-weighted imaging. On T2-weighted imaging 16 homogeneous (50.0% and 5 inhomogeneous (15.6%) cysts showed signal intensities equal to or higher than subcutaneous fat. The peripheral rims of 11 ring-like cysts (34.4%) also showed signal intensities equal to or higher than subcutaneous fat on T2-weighted imaging. Nine patients (37.5%) had multiple cysts. Their characteristic high signal intensities or ring-like patterns on T2-weighted imaging and well-demarcated margins enabled them to be discriminated from other tumors of the maxillary sinus, such as carcinoma. CONCLUSION: MR imaging is useful for diagnosis of POMC.

Female↗
PubMedDate not supplied

Torsion of the wandering spleen: CT and angiographic appearance.

OBJECTIVE: To seek CT and angiographic appearances that characterize torsion of the wandering spleen. MATERIALS AND METHODS: The CT and angiographic findings of two cases of preoperatively diagnosed torsion of the wandering spleen were reviewed, and the findings were closely compared with intraoperative and histopathological findings. RESULTS: Characteristic CT appearance seemed to be a whirled appearance formed at the medial side of the displaced spleen. The angiographic finding that was characteristic of the disease was a tapered and abruptly twisted distal splenic artery. CONCLUSION: These findings were useful in making the early and correct diagnosis of this rare but fulminant condition.

Adolescent↗
PubMedDate not supplied

Anterior extension of acute pancreatitis: CT findings.

OBJECTIVE: The purpose of this study is threefold: (a) to specify the pathway of the extension of pancreatitis to the anterior abdominal wall, which is clinically famous as the Cullen sign; (b) to assess if this pattern of involvement affects a patient's prognosis; and (c) to seek its association with the inflammatory processes that take place in the vicinity of the pancreatic head. MATERIALS AND METHODS: The CT findings of 277 patients with acute pancreatitis were retrospectively reviewed. RESULTS: Inflammatory changes involved the anterior abdominal wall in 5 of 277 cases (1.8%) with acute pancreatitis. Inflammatory processes seemed to have been delivered to the anterior abdominal wall from the pancreatic head and the hepatoduodenal ligament and along the falciform ligament. The probable triggers of acute pancreatitis in such cases were endoscopic retrograde cholangiopancreatography in two cases, alcohol intake in one case, and one case unknown. Three of five cases had proven or suspected choledocholithiasis or cholelithiasis. All five patients got well after proper treatments for acute pancreatitis. CONCLUSION: The results of our review suggest that the anterior extension of acute pancreatitis does not directly mean extensive retroperitoneal involvement of the phlegmon or pseudocysts nor fatal prognosis either and that this style of extension might be associated with inflammatory processes that occur around the pancreatic head.

Acute Disease↗
PubMedDate not supplied

MRI of dumbbell-shaped spinal tumors.

PURPOSE: The purpose of our study is to review the clinical features and MR findings in patients with dumbbell-shaped spinal tumors that affect the intervertebral foramen. METHOD: Two radiologists retrospectively evaluated a total of 19 tumors from the period 1989-1994 that exhibited dumbbell configuration. These included 11 benign tumors, including 9 neurogenic ones, and 8 malignant tumors. RESULTS: The time between onset of symptoms and admission was shorter in patients with malignant tumors (mean 3.9 months) than in patients with benign tumors (mean 41.1 months). There was a statistically significant difference (p < 0.05) in the short/long axis ratios (minimum tumor diameter divided by maximum tumor diameter) in the vertebral canal components between benign and malignant tumors. All malignant tumors in this study were extradural and paraspinal type (p < 0.05). Most benign tumors had regular margins and enlarged intervertebral foramina, while most malignant ones had irregular margins (p < 0.05). Many neurogenic tumors had regular margins and enlarged intervertebral foramina, while most malignant ones had irregular margins (p < 0.05> Many neurogenic tumors had cystic lesions (77.8%) and a string-of-beads structure (44.4%). Those tumors that surrounded the thecal sac in the vertebral canal and whose adjacent vertebral bodies had abnormal signal intensities were infiltrating and malignant. CONCLUSION: There are many kinds of dumbbell-shaped spinal tumors other than neurogenic ones. MRI is useful in diagnosing dumbbell-shaped spinal tumors, especially those of neurogenic origin, and aids in distinguishing benign from malignant tumors.

Adolescent↗
PubMedDate not supplied

MRA of intracranial aneurysm models: a comparison of contrast-enhanced three-dimensional MRA with time-of-flight MRA.

PURPOSE: The purpose of our study was to compare contrast-enhanced 3D MR angiography (MRA) using ultrafast spoiled gradient-recalled acquisition in the steady state (SPGR) with 2D and 3D time-of-flight (TOF) MRA for visualization of intracranial lateral saccular aneurysm models. METHOD: We used lateral saccular aneurysm models with a height of 10 mm and neck sizes of 2.5 and 10 mm. Imaging was performed using a 1.5 T MR system with a head coil. Contrast-enhanced 3D MR angiograms were obtained using 3D ultrafast SPGR sequence with and without the MR Smartprep technique. Two-dimensional and 3D TOF MR angiograms were also obtained. RESULTS: Contrast-enhanced multiphase 3D MR angiograms taken every 5 s after injection of contrast medium proved superior to the other MRA techniques for delineating lateral saccular aneurysm models. Contrast-enhanced 3D MRA images taken with inadequate delay after MR Smartprep trigger showed poor visualization of the aneurysm model. CONCLUSION: Use of contrast-enhanced multiphase 3D MRA with ultrafast SPGR with shorter TR and TE resulted in clear images of the lateral saccular aneurysm model.

Contrast Media↗
PubMedDate not supplied

BOLD contrast on a 3 T magnet: detectability of the motor areas.

To predict the potential and the limitations of functional MRI (fMRI) with a very high field magnet, the detectability and reproducibility of activation were evaluated by comparing the activation induced by a sequential finger movement task at 1.5 T with that at 3 T. The detectability of the premotor area, supplementary motor area (SMA), and ipsilateral sensorimotor area (SM1) showed significant improvement at 3 T. On the other hand, the detectability of contralateral SM1 was not significantly different between 1.5 and 3 T. The degree of activation was proportional to task demand in the ipsilateral SM1 and SMA, whereas that in the contralateral SM1 and SMA was not. FMRI with a 3 T magnet has greater potential for detection of neuronal activation as a functional network. These observations indicated that task demand and static magnetic field strength should be considered in interpretation of fMRI data for clinical usage.

Adult↗
PubMedDate not supplied

Adult intussusception with an appendiceal mucocele diagnosed by CT and ultrasonography.

Mucocele of the appendix is rare and mainly found incidentally at surgery or autopsy. Clinically, this tumor is known to cause pseudomyxoma peritonei or intussusception in adults. We present a case of adult intussusception with a leading mass of appendiceal mucocele. Computed tomography was useful in resolving the nature of the leading mass.

Aged↗
PubMedDate not supplied

Caroli's disease associated with polycystic kidney: its noninvasive diagnosis.

We present a case of Caroli's disease, a relatively uncommon congenital abnormality, together with CT, US, and scintigraphic findings. The patient had chronic renal failure, complicated by polycystic kidney. No hepatic fibrosis was observed. Intrahepatic biliary lithiasis and gallstones were detected, but the patient was asymptomatic. Because surgery on an abnormal biliary tract may increase the risk of cholangitis, and intravenous administration of contrast media could be invasive in patients with polycystic kidney, CT, US, and scintigraphy are considered to play an important role in diagnosis. Noninvasive diagnostic procedures in Caroli's disease are described in this report.

Aged↗