Biomedical subjects

K Masuda

Publications and source records attributed to K Masuda.

970 records · Page 54Linked to original sources

PubMedDate not supplied

Computed tomographic findings of invasive transitional cell carcinoma in the kidney.

CT findings of 10 cases of transitional cell carcinoma with renal parenchymal involvement were reviewed. CT showed a low-density mass with varying degrees of renal parenchymal involvement. Intrarenal transitional cell carcinomas were characterized by preserved renal contour with abnormalities of the collecting system such as obliteration, entrapment in the tumor, dilatation, and intraluminal mass. Obliteration of the renal sinus fat and poorly defined tumor margin were other characteristic CT features. This study indicated that CT is useful for differentiating transitional cell carcinomas with renal parenchymal involvement from renal cell carcinomas.

Adipose Tissue↗

PubMedDate not supplied

Improvement of chemical analysis of antibiotics. Part XIX: Determination of tetracycline antibiotics in milk by liquid chromatography and thin-layer chromatography/fast atom bombardment mass spectrometry.

A precise liquid chromatographic (LC) determination with high sensitivity and a reliable mass spectrometric (MS) confirmation were established for the determination of tetracycline antibiotics (TCs) in milk. The determination of the TCs was based on C18 cartridge cleanup followed by LC separation. Recoveries of TCs from milk fortified at 20 ppb were 73.0-81.8%, and coefficients of variation were 2.6-4.6%. With this method, concentrations of oxytetracycline and tetracycline as low as 10 ppb and chlortetracycline and doxycycline as low as 20 ppb were determined readily. Thin-layer chromatography (TLC)/fast atom bombardment (FAB) MS with a condensation technique was used to confirm TCs in milk. After the C18 cartridge cleanup, separation on a C8 TLC plate, and application of the sample condensation technique, FAB mass spectra were measured. TCs in milk at 50 ppb were reliably confirmed by TLC/FABMS.

Animals↗

PubMedDate not supplied

Isolated Crohn's disease of the gastroduodenum: a case report.

We report a case of isolated Crohn's disease in the gastroduodenum. A 33-year-old man was hospitalized due to epigastralgia. Endoscopic and double-contrast radiographic studies revealed edematous gastroduodenal mucosa with a deep, undermining ulceration in the gastric antrum, which changed after a short interval into a typical "cobblestoned" appearance. A gastrectomy was performed due to antral narrowing, and Crohn's disease was histologically confirmed. Our objective was to reveal the change from a deep, undermining ulceration to a typical "cobblestoned" appearance using a double-contrast barium study.

Adult↗

PubMedDate not supplied

MR imaging compared with CT, angiography, and myelography supplemented with CT in the diagnosis of spinal tumors.

To clarify the significance of MR imaging and the present status of CT, angiography, and myelography supplemented by CT (M-CTM), the radiological findings of 50 spinal tumors were reviewed and analyzed. MR imaging was most effective for visualizing morphological features such as the margins and/or inner structures of the tumors. CT was also effective for imaging "dumbbell" neurinomas and extradural tumors. Angiography was necessary in one hemangioblastoma and in cervical extradural tumors. M-CTM visualized the morphology of intradural extramedullary tumors and extradural tumors, but provided no new information in most of these cases. It was concluded that when using MR the indications for CT, angiography, and M-CTM are limited and that CT or angiography should be performed only in selected cases. M-CTM appeared to be unnecessary.

Adolescent↗

PubMedDate not supplied

Intrahepatic peripheral cholangiocarcinoma: two-phased dynamic incremental CT and pathologic correlation.

To elucidate the characteristic CT findings of intrahepatic peripheral cholangiocarcinoma, two-phased dynamic incremental CT scans of 20 cholangiocarcinomas in 16 patients were carefully analyzed. Dynamic incremental CT scanning was performed after intravenous administration of 100 ml iodinated contrast medium at a rate of 2 ml/s using a power injector. The CT scans (8-16 sections) were obtained during 45-110 s (early phase) and 6-7 min (delayed phase) after commencement of the injection of the contrast medium. On CT, 55% (11 of 20) of intrahepatic peripheral cholangiocarcinomas appeared hypodense in both phases. Most of the tumors (80%) appeared hypodense in the early phase and had increased CT numbers in their delayed images. Lymphadenopathy was observed in 69% (11 of 16) of patients whose main tumors exceeded 3 cm in diameter. All tumors appeared irregular or indistinct. Twenty percent (4 of 20) of the cholangiocarcinomas were difficult to distinguish from hepatocellular carcinomas or hemangiomas.

Adenoma, Bile Duct↗

PubMedDate not supplied

Solitary choroid plexus lipomas: CT and MR appearance.

Using MR imaging, the authors detected 23 cases of intracranial lipomas, among which were three cases of solitary choroid plexus lipomas. All the lipomas were located in the choroid plexus at the trigone. One of the three solitary choroid plexus lipomas was very small and could not be detected using CT. The authors believe that solitary choroid plexus lipomas are not as rare as was previously thought.

Adult↗

PubMedDate not supplied

Postcontrast 3D-TOF-MR angiography of intracranial venous angiomas.

The clinical value of three-dimensional time-of-flight magnetic resonance angiography (3D-TOF-MRA) was assessed in 15 patients with intracranial venous angiomas (VAs), by comparing results thereof with those of postcontrast T1-weighted MR images (MRIs). All 15 VAs were identified both on the postcontrast MRIs and MRAs. The MRAs surpassed the MRIs in imaging entire structures, including the draining veins of the supratentorial VAs. For the infratentorial VAs, the MRAs and the MRIs were of equal value. Although the addition of MRA to the MRI procedure incurs more time and expense, the complete structure of the VA can thereby be identified three-dimensionally on MRA. Conventional angiography is apparently not required for the confirmation of a VA. Thus, it is concluded that MRA is very useful for diagnosing VAs.

Adolescent↗

PubMedDate not supplied

Intracranial metastasis of renal cell carcinoma: MR imaging.

The purpose of this study was to evaluate the magnetic resonance (MR) findings of intracranial metastatic tumors of renal cell carcinomas (RCCs). MR images of seven patients with intracranial metastases of RCCs were retrospectively reviewed. Each of the seven patients had a single lesion, including five supratentorial intraparenchymal lesions, one 4th ventricular lesion, and one pituitary lesion. Intra- and/or peritumoral flow voids were observed in five of the seven lesions. The signal intensities of the tumors were not specific. All lesions showed gadolinium enhancement, including solid (3), nearly solid (2), and ring enhancement (2). We concluded that intra- and/or peritumoral flow void is a relatively characteristic MR finding of intracranial metastases of RCCs.

Aged↗

PubMedDate not supplied

CT diagnosis of pleural dissemination without pleural effusion in primary lung cancer.

We retrospectively reviewed the CT scans of 25 primary lung cancers with disseminated pleural nodules or minimal malignant pleural effusions that were not recognized preoperatively. Special attention was devoted to abutting interlobar fissures, thick major fissures, and disseminated nodules on the chest wall, the diaphragm, and in the interlobar fissures. Among 10 primary tumors abutting interlobar fissures, nine (90%) had at least one of these findings. Among 15 primary lung tumors which did not abut interlobar fissures, four (27%) had at least one of these findings. We conclude that CT is a useful modality for detecting the pleural dissemination of primary lung cancers when primary lung cancers abut interlobar fissures even if no pleural effusion is detectable on CT.

Adult↗

PubMedDate not supplied

Intra-arterial digital subtraction angiography with extra-large fields using a computed radiography system in evaluating peripheral vascular disease.

The authors evaluated the usefulness of intra-arterial digital subtraction angiography (DSA) with extra-large field sizes using a computed radiography (CR) system in evaluating peripheral vascular disease (PVD). Intra-arterial DSA using CR was performed in 55 patients with suspected PVD. A 4 F catheter was advanced into the abdominal aorta via the transbrachial approach and 90 ml of contrast medium was injected during six exposures using a long leg changer mounting a total of 18 imaging plates on six surfaces. Visualization of the superficial femoral and popliteal arteries was judged as diagnostic in all cases. The abdominal aorta, iliac arteries, and subtrifurcation were also visualized in most cases, but visualization was suboptimal in some cases. As a complication, median nerve palsy occurred in one case. This technique is thought to be a useful method for evaluating PVD because of the advantages of a large field of view and wide exposure latitude, in spite of its relatively long processing time.

Aged↗

PubMedDate not supplied

MR imaging of focal nodular hyperplasia of the liver: value of contrast-enhanced dynamic study.

To clarify the role of MR imaging of hepatic focal nodular hyperplasia (FNH), MR images of 11 patients with 13 FNH were retrospectively reviewed. MR imaging with T1- and T2-weighted spin echo sequences was performed for all lesions. Dynamic studies using the SPGR technique followed by postcontrast delayed T1-weighted images were performed in four patients with five lesions. Gd-DTPA enhanced T1-weighted images were obtained in five patients with six lesions. Two patients with single lesions received no contrast agent. The signal intensity, morphologic appearance, and enhancement patterns were evaluated. Dynamic MR study revealed homogeneous early vigorous enhancement and prolonged enhancement in all five lesions. On T1-weighted images, three lesions were hypointense, six were isointense, and four were hyperintense to the surrounding hepatic parenchyma. On T2-weighted images, four lesions were isointense and nine were hyperintense. A central scar was identified in eight lesions and showed delayed enhancement. It is concluded that dynamic MR studies are mandatory for diagnosing FNH.

Adolescent↗

PubMedDate not supplied

Dural non-cavernous sinus arteriovenous fistulas symptomatically simulating spontaneous carotid-cavernous fistulas: an analysis of angiographic findings.

The sites of fistulas and patterns of venous drainage in 34 consecutive cases of dural AVFs manifesting symptoms suggesting CCFs were retrospectively analyzed to determine the frequency of dural AVFs in sites other than the cavernous sinus and to ascertain their causative mechanisms. In five cases (15%), dural AVFs were demonstrated in sites other than the cavernous sinus. Among four, retrograde venous flow due to occlusion of the outflow tract or a rapid-flow shunt resulted in filling of the superior ophthalmic vein. A rapid-flow dural AVF in the anterior cranial fossa showed no occlusive changes in the sinuses, and increased pressure in the cavernous sinus was thought to be responsible for the symptoms. Embolization was effective for relief of the symptoms. Symptoms mimicking CCFs can be seen in dural AVFs in sites other than the cavernous sinus with retrograde venous drainage or with a rapid-flow shunt, conditions which are not as rare as previously believed.

Adult↗

PubMedDate not supplied

Neural network analysis of breast cancer from MRI findings.

PURPOSE: To evaluate how much the experience of radiologists affects the performance of an artificial neural network (ANN) trained by two highly experienced radiologists. MATERIALS AND METHODS: Before biopsy two experienced radiologists reviewed the MR images of 100 adult patients with suspicious breast lesions and evaluated their findings based on six features. This database was then used to train a three-layered feed-forward neural network. The network's generalizing ability was then tested to predict the outcome of biopsy in 56 new patients' records which were extracted by 10 participating radiologists. The MRI findings of each reader were presented to the ANN to evaluate the effect of various levels of experience on the output of the ANN. The performance of the ANN was then compared with that of attendant physicians in terms of sensitivity, specificity, and accuracy as well as ROC analysis. RESULTS: The best ANN outcome offered a correct diagnosis in 40 of 41 of the patients with malignant breast cancer and 10 of 15 with benign entity presented in the testing set. The output of the trained ANN outperformed the attendant radiologists with low levels of experience and showed comparable performance with radiologists with higher levels of experience. CONCLUSIONS: The ANN is able to work as a backup system to assist radiologists in the diagnosis of breast cancer.

Adolescent↗

PubMedDate not supplied

Intracranial penetrating injuries via the optic canal.

Two cases of intracranial penetration of a plastic or wooden chopstick via the optic canal are described. CT scans showed the chopsticks as linear hypodense structures in the suprasellar cistern contiguous with the optic canal. In one case, MR imaging was performed, which clearly depicted the foreign body and adjacent brain structures. Although they are extremely rare, transorbital intracranial penetrating injuries via the optic canal require physicians' awareness.

Brain Injuries↗

PubMedDate not supplied

Adaptive spatial filtering technique for storage phosphor radiography in portable chest radiographs: parameter optimization.

PURPOSE: To investigate the optimal parameters of adaptive spatial filtering (ASF) in storage phosphor radiography for processing portable chest radiographs. MATERIALS AND METHODS: Two types of weighting factor curves starting at 383 digital pixel values (PV) (type B) and at 511 PV (type C) were selected for the optimization of ASF. The PV of 27 areas of apparent pulmonary lesions and seven retrocardiac areas were measured for original unprocessed and ASF-processed images. Three radiologists compared 30 ASF-processed portable chest radiographs with apparent pulmonary or pleural lesions with unprocessed images. RESULTS: PV measurements revealed no significant change in pulmonary densities in type B, and an increase in PV of lower pulmonary densities in type C. Densities of retrocardiac areas were more enhanced in type C than in type B. Observer testing showed that pulmonary densities were evaluated as unchanged in 90% of type B images and 76% of type C images. Changes in mediastinal densities were evaluated as adequate in 80% of type B and 90% of type C images. CONCLUSION: The starting point of the weighting factor curve of ASF in portable chest radiographs should be set the same as in chest radiographs in the upright posteroanterior position with high kVp.

Algorithms↗

PubMedDate not supplied

Consistency of variables in PCS and JASTRO great area database.

PURPOSE: To examine whether the Patterns of Care Study (PCS) reflects the data for the major areas in Japan, the consistency of variables in the PCS and in the major area database of the Japanese Society for Therapeutic Radiology and Oncology (JASTRO) were compared. METHODS AND PATIENTS: Patients with esophageal or uterine cervical cancer were sampled from the PCS and JASTRO databases. From the JASTRO database, 147 patients with esophageal cancer and 95 patients with uterine cervical cancer were selected according to the eligibility criteria for the PCS. From the PCS, 455 esophageal and 432 uterine cervical cancer patients were surveyed. Six items for esophageal cancer and five items for uterine cervical cancer were selected for a comparative analysis of PCS and JASTRO databases. RESULTS: Esophageal cancer: Age (p=.0777), combination of radiation and surgery (p=.2136), and energy of the external beam (p=.6400) were consistent for PCS and JASTRO. However, the dose of the external beam for the non-surgery group showed inconsistency (p=.0467). Uterine cervical cancer: Age (p=.6301) and clinical stage (p=.8555) were consistent for the two sets of data. However, the energy of the external beam (p<.0001), dose rate of brachytherapy (p<.0001), and brachytherapy utilization by clinical stage (p<.0001) showed inconsistencies. CONCLUSION: It appears possible that the JASTRO major area database could not account for all patients' backgrounds and factors and that both surveys might have an imbalance in the stratification of institutions including differences in equipment and staffing patterns.

Adult↗