Biomedical subjects
Publications and source records attributed to Masafumi Uchida.
We report a case of giant cell-rich osteosarcoma in the right distal femur of a 32-year-old man. Giant cell-rich osteosarcomas are sometimes difficult to distinguish from giant cell tumors by age, location, magnetic resonance imaging findings, and pathology. Radiography may be useful in the diagnosis of giant cell-rich osteosarcoma.
PURPOSE: This study was performed to investigate the role of injection methods and conditions under a fixed dose of radiographic contrast medium (CM) in respect to promoting blood-brain barrier (BBB) disruption. MATERIALS AND METHODS: A total of 44 white rabbits (average body weight 2.7 +/- 0.4 kg) were used, and their carotid injection was performed with nonionic CM. The variables assessed for the carotid injections included the following: iodine content (300 or 150 mg I/ml), liquid temperature (37 degrees or 24 degrees C), and the injection time duration (1 or 30 s). The rabbits were divided into five groups. To evaluate BBB disruption, pre- and post-contrast-enhanced magnetic resonance (MR) studies were performed. RESULTS: Abnormal enhancement of the brain parenchyma in MRI was noted in only one group, which consisted of high-iodine concentration CM injected at a low temperature over a short injection interval. Statistically significant increased values for the percentage of relative enhancement (RE%) were demonstrated (P < 0.05) in comparison with the saline-injected control group. CONCLUSION: This result suggests variables that may need to be carefully considered to prevent BBB injury induced by nonionic CM for cerebral angiography, especially in the setting of a neurointerventional procedure.
Angioleiomyomas are smooth muscle tumors that occur most often in the extremities and are usually less than 2 cm in diameter. We present 2 case reports of giant angioleiomyoma. Case 1 was a 51-year-old woman with a 5-year history of a slowly growing mass 12x10 cm in diameter in the right posterior thigh. The tumor was larger than any previously reported. Case 2 was a 72-year-old man with an 8-year history of a slowly growing mass 6x6 cm in diameter in the left palm. The tumor was unique in that it grew to a giant size in the hand of the elderly patient. Magnetic resonance imaging of both cases confirmed the tumors' presence in the subcutis. T1-weighted images showed homogenous signal isointense to muscle. On T2-weighted images, areas of hyperintensity and hypointensity intermingled. Three-dimensional gadolinium-enhanced magnetic resonance angiography showed rapid initial enhancement followed by a gradual increase in enhancement, suggesting that the tumors were rich in vessels. Microscopic examination revealed numerous vascular channels embedded within a huge smooth muscle component.
A case of uterine lipoleiomyoma in a 72-year-old woman is presented. Although a series of imaging studies suggested a lipomatous tumor, diagnosis was difficult because the tumor appeared as a pedunculated mass extending from the uterine body. To distinguish the tumor from an ovarian lipomatous tumor, the "beak sign" in a magnetic resonance imaging study was diagnostic in this case. The purpose of this paper is to review lipomatous masses of the female pelvis, to discuss the differential diagnosis of the unusual imaging features, and to discuss imaging techniques to optimize pelvic mass characterization.
OBJECTIVE: We evaluated the feasibility of creating 3D and multiphase fusion images of cholangiocarcinoma. The 3D rendering of the biliary tree provide valuable information for planning surgery, including the location of the obstruction and its relationship to the surrounding vessels. CONCLUSION: Our data emphasize that 3D and multiphase fusion images may be an accurate and routinely applicable tool for the diagnosis and therapeutic management of patients with biliary system abnormalities.
OBJECTIVE: The purpose of our study was to compare the high-resolution CT and pulmonary function test findings of smokers and nonsmokers with pulmonary sarcoidosis. MATERIALS AND METHODS: Full inspiratory and expiratory high-resolution CT of the thorax and pulmonary function tests were performed in 46 patients (23 smokers and 23 lifelong nonsmokers) with histologically proven sarcoidosis. The median interval between high-resolution CT and pulmonary function tests was 8 days (range, 0-27 days). High-resolution CT findings were categorized into six patterns, and the overall extent of each pattern was scored independently (high-resolution CT score). Correlation between each high-resolution CT score with each pulmonary functional parameter was performed using Spearman's rank correlation and stepwise multiple regression analysis. RESULTS: Air trapping on expiration (45/46 patients, 98%) and small nodules on inspiration (all 46 patients, 100%) were the most common findings. Smokers had a greater extent of emphysema than nonsmokers (p = 0.002). No significant difference was seen in the extent of air trapping, consolidation, ground-glass attenuation, reticular opacities, or small nodules between smokers and nonsmokers. On Spearman's rank correlation, the extent of air trapping negatively correlated with forced vital capacity in smokers (p < 0.05) but not in nonsmokers. The extent of small nodules negatively correlated with forced vital capacity and positively correlated with the ratio of forced expiratory volume in 1 sec to forced vital capacity in nonsmokers (p < 0.05, both) but not in smokers, respectively. On stepwise multiple regression analysis, the extent of air trapping on CT was independently associated with decreased forced vital capacity (p < 0.05), and cigarette smoking was the main determinant of decrease in maximum midexpiratory flow and forced expiratory flow at 50% of vital capacity (p < 0.01). CONCLUSION: Cigarette smoking confounds the correlation between the CT and pulmonary function test findings in patients with sarcoidosis. Therefore, smoking history must be taken into account when correlating the extent of parenchymal sarcoidosis on CT with functional impairment.
PURPOSE: To evaluate the usefulness of diffusion-weighted MRI in distinguishing different components and in differentiating benign from malignant musculoskeletal tumors. MATERIALS AND METHODS: Fifty-seven patients with musculoskeletal tumors underwent MR at our institution from October 1999 to April 2002. We evaluated 57 tumors (9 bone tumors and 48 soft tissue tumors). All tumors were classified into 8 groups (myxomatous, fibrous, cystic, cartilaginous, fatty components, hematomas, other benign tumors, and other malignant tumors). MR examinations were performed with a 1.5-Tesla system. Diffusion-weighted single-shot EPI images were obtained in all patients. Apparent diffusion coefficients (ADCs) were calculated by using b factors of 0 and 1,000 sec/mm2. RESULTS: ADC values of myxomatous, cystic, and cartilaginous components were significantly higher than those of other tumors. In cartilaginous tumors, malignant tumor ADC values (2.33 +/- 0.44) were higher than those of benign tumors (2.13 +/- 0.13). However, there was no significant difference between benign and malignant tumors. Except for high-intensity components on T1-weighted imaging and low or homogeneously very high intensity components on T2-weighted imaging, there was a significant difference in ADC between malignant (1.35 +/- 0.40) and benign (1.97 +/- 0.50) tumors. CONCLUSION: Within the limited number of cases, there was a significant difference in ADC between malignant and benign tumors.
BACKGROUND: Prosthetic valve dysfunction (PVD) as a result of pannus or thrombus formation is an infrequent but serious complication. Currently available diagnostic tools, however, are insufficient to detect a minute pannus and thrombi. The use of a more advanced diagnostic image, multidetector-row computed tomography scanner, may enable us to determine the anatomic and functional causes of PVD. METHODS: Patients who underwent aortic valve replacement with a St. Jude Medical valve were examined by transthoracic echocardiography and cineradiography to diagnose PVD. Sixteen patients with PVD (PVD group) and 12 patients with normal prosthetic valve function (control group) were studied using the multidetector-row computed tomography scanner. The multidetector-row computed tomography findings in 2 patients with PVD were validated by the observations during reoperation. RESULTS: In 13 of 16 patients (81%) in the PVD group and 3 of 12 patients (25%) in the control group, multidetector-row computed tomography demonstrated that an abnormal small tissue, regarded as pannus, was found to extend from the left ventricular septum into the pivot guard. These findings were confirmed by the observations during reoperation in 2 patients in the PVD group. CONCLUSIONS: Multidetector-row computed tomography can be a useful diagnostic technique for anatomic and functional evaluation of PVD as a result of pannus formation.
Prosthetic valve dysfunction (PVD) due to pannus formation is an infrequent but serious complication. A 72-year-old man who underwent aortic valve replacement was diagnosed with PVD and aneurysm of the Sinus of Valsalva. Multidetector-row computed tomography (MDCT) was used to examine the cause of PVD before reoperation. MDCT demonstrated that tissue regarded as pannus extended from the left ventricular septum into the pivot guard. These findings were confirmed by observations during reoperation. MDCT can be a useful diagnostic technique for the anatomical and functional evaluation of PVD.
The purpose of this study was to determine the feasibility of virtual endoscopy, named as "virtual CT laparoscopy", in the hepatobiliary system prior to laparoscopic cholecystectomy. We applied this technique to 28 patients suspected of having biliary disease. These images were compared and analyzed qualitatively based on visualization of the structures critical to operative cholangiography and surgical findings. Twenty-four patients, who underwent laparoscopic cholecystectomy, were evaluated as follows: the common bile duct and the hepatic duct were adequately visualized in 23 (96%) of the 24 patients, the cystic duct in 21 (88%), the gallbladder opacification in 20 (83%), the liver inferior surface in 20 (83%). Four patients had anatomic variations detected virtual CT laparoscopy and were proven by operative cholangiography and surgical findings. We emphasize that our new technique may contribute to the laparoscopy during surgery as the aid of understanding of anatomical structures in these organs.
The 3-dimensional image was excellent as a result of the fast scanning and narrow collimation using multidetector computed tomography (CT); and the parallel escalation in the capabilities of the workstation allow the use of CT angiography/CT cholangiography image fusion. We demonstrated the feasibility of fusion images of the hepatobiliary system. We believe that fusion images are extremely valuable for applications such as preoperative planning for hepatic and bile duct resection.
PURPOSE: The purpose of this study was to evaluate the feasibility and image quality of a novel biliary imaging technique that obtains 3D cholangiography image sets by infusing contrast material through a PTC-drainage tube, using 3D-digital subtraction angiography (DSA). METHODS: We applied this technique to seven patients suspected of having biliary disease. All patients underwent PTCD because of obstructive jaundice. Contrast material was introduced through the drainage tube, and the raw data were then transferred automatically to a workstation. Approximately 3 minutes of user time was required to generate the 3D images following image acquisition. RESULTS: Three-dimensional cholangiography was obtained in all patients who underwent 3D-DSA examination. Acceptable quality 3D-DSA cholangiograms were generated in six of the seven patients. CONCLUSION: We emphasize that our new technique may help during surgery as an aid to understanding anatomical structures in the biliary system.
Once hepatocellular carcinoma (HCC) develops, it repeats intrahepatic metastasis and has multicentric occurrence, which requires frequent treatment. We designed a phase II clinical trail to clarify whether antineoplaston AS2-1, a mixture of sodium salts of phenylacetylglutamine and phenylacetic acid at a ratio of 1:4, prolongs the recurrence-free interval of HCC patients who undergo frequent treatments for recurrence. Ten patients were enrolled in this trial, 2 in stage I, 6 in stage II, 1 in stage III, 1 in stage IV-B at initial diagnosis. Ten patients experienced 35 recurrence-free intervals. Recurrence-free intervals during antineoplaston AS2-1 administration were significantly longer than those without antineoplaston AS2-1 (16.19+/-15.916 versus 5.05+/-2.897 months: p<0.01). Patients who experienced recurrence-free intervals with and without antineoplaston AS2-1 showed longer intervals during antineoplaston AS2-1 administration than those before and after antineoplaston AS2-1 administration (14.47+/-13.821 versus 5.07+/-2.989 versus 5.02+/-3.009 months: p<0.05). Two patients in stage I showed longer recurrence-free intervals than those in more advanced stages. In conclusion, antineoplaston AS2-1 could not prevent recurrence of HCC but prolonged the recurrence-free interval between regional treatments and improved survival rate of these patients.
OBJECTIVE: To evaluate the usefulness of pancreatic enhancement using a high concentration of contrast material in CT. METHODS: We performed abdominal CT on 125 patients after dividing them at random into five groups with two different concentrations, two different injection rates and three different injection doses: group A: 100 ml, 300 mgI/mL, 3 mL/sec; group B: 2 mL/kg, 300 mgI/mL, 3 mL/sec; group C: 1.5 mL/kg, 370 mgI/mL, 3 mL/sec; group D: 2 mL/kg, 300 mgI/mL, 5 mL/ sec; and group E: 1.5 mL/kg, 370 mgI/mL, 5 mL/sec. Among these five groups, the two groups given a concentration of 370 mgI/mL received a dose of 1.5 mL/body weight. RESULTS: The peak enhancement value of the pancreas was significantly greater in group E than in groups A and B. However, no statistically significant differences were found among the other groups. CONCLUSION: The fast injection rate using the high concentration of contrast medium provided greater enhancement of the pancreas than the slow injection rate using the routine concentration of contrast medium, and pancreatic CT enhancement depended more on the dose of iodine per second than on that of total iodine.