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Biomedical subjects

T Kozuka

Publications and source records attributed to T Kozuka.

At least 127 records · Page 7Linked to original sources
PubMed1992

Subluxation of the patella: evaluation of patellar articular cartilage with MR imaging.

In patients with subluxation of the patella, injury of the patellar articular cartilage is frequently observed, and correct evaluation of this cartilage injury is extremely important for the management of these patients. Magnetic Resonance (MR) studies were performed on 102 patellofemoral (PF) joints of 51 patients with subluxation of the patella and 20 PF joints of 10 healthy volunteers. In 77 of the 102 PF joints with subluxation, arthroscopy and/or operation were performed. MR images were obtained with spin-echo and FLASH sequences, and para-axial images were obtained. We retrospectively analysed the MR findings of the 77 joints with special attention to the surface and thickness of the cartilage, and classified them into four grades. These MR grades were compared with the grades on arthroscopy, and the following results were obtained: MR grade 0, normal cartilage (n = 27, sensitivity 90.9%, specificity 74.2%); MR grade 1, thickening of the cartilage (n = 24, sensitivity 50%, specificity 89.1%); MR grade 2, surface irregularity of the cartilage (n = 20, sensitivity 85%, specificity 94.7%); MR grade 3, loss of the cartilage (n = 6, sensitivity 100%, specificity 100%). Although the early changes observed by arthroscopy were underestimated from the MR images, MR imaging proved to be extremely useful for evaluating moderately or advanced patellar cartilage injury.

Adolescent↗
PubMed1992

Summer-type hypersensitivity pneumonitis: comparison of high-resolution CT and plain radiographic findings.

Summer-type hypersensitivity pneumonitis is an immunologic disease that occurs only in Japan. It is a form of hypersensitivity pneumonitis in which the clinical symptoms appear in the summer and subside spontaneously in mid autumn. The purpose of our study was to determine the CT findings in this condition, to compare the CT findings with those on chest radiographs, and to assess the variations in the CT findings over time. Accordingly, high-resolution CT scans and chest radiographs of 15 patients with summer-type hypersensitivity pneumonitis were retrospectively studied. Seven patients had sequential CT examinations 18-37 days apart. The CT scans and chest radiographs were reviewed by two observers independently. CT findings included diffuse micronodules (n = 15), slightly elevated lung density (n = 13), and patchy air-space consolidation (n = 13). In one patient, the findings on a chest radiograph were normal, while CT showed parenchymal abnormalities. In two cases, follow-up CT showed micronodular abnormalities after findings on the chest radiograph had returned to normal. Our results show that high-resolution CT findings of summer-type hypersensitivity pneumonitis include pulmonary micronodules, increased lung density, and air-space consolidation. High-resolution CT appears to be more useful than plain chest radiographs in the evaluation of pulmonary parenchymal abnormalities in this condition.

Adult↗
PubMed1992

CT appearance of pulmonary tuberculosis in diabetic and immunocompromised patients: comparison with patients who had no underlying disease.

OBJECTIVE: It has been stated, but not adequately assessed, that pulmonary tuberculosis in diabetic or immunocompromised patients often has an atypical pattern and distribution. To evaluate the CT features of pulmonary tuberculosis in diabetic or immunocompromised patients compared with patients without underlying disease, we performed this retrospective study. MATERIALS AND METHODS: We reviewed conventional CT scans (n = 100) and high-resolution CT scans (n = 16) of the chest in 110 adult patients with active postprimary tuberculosis. Seventy-one patients had no underlying disease, 31 had diabetes mellitus, and eight were immunocompromised. RESULTS: In patients who had no underlying disease, 44 had nodular opacities, 11 had consolidation, and 13 had consolidation with associated loss of volume. Characteristic features of tuberculosis in this group of patients included segmental distribution (97%), satellite lesions (93%), single cavity within any given lesion (95%), and tendency toward architectural distortion and loss of volume. In diabetic and immunocompromised patients, 15 had nodular opacities, seven had consolidation, and 15 had consolidation with associated loss of volume. Diabetic and immunocompromised patients had a high prevalence of nonsegmental distribution (30%) and multiple small cavities within any given lesion (44%). Unusual localization of tuberculosis, including disease confined to the basal segments of the lower lobes, anterior segment of the upper lobes, or right middle lobe, occurred equally in both groups (17% and 18%). CONCLUSION: We conclude that diabetic and immunocompromised patients have a higher prevalence of multiple cavities within any given lesion (p < .01) and of nonsegmental distribution (p < .01) than do patients without underlying disease.

Adult↗
PubMed1992

[Stage III, IV hepatocellular carcinoma patients surviving more than five years after transcatheter chemoembolization].

Twelve of the patients with advanced (Stage III or IV) hepatocellular carcinoma who received transcatheter chemoembolization survived for more than 5 years. These survivors consisted of 6 Stage III cases and 6 Stage IV cases. Of the 6 Stage III cases, 5 had multiple tumors (larger than 2 cm) in one lobe of the liver, and 1 had tumor invasion into the second portal branch before treatment. Of the 6 Stage IV cases, 4 had had multiple tumors in both lobes, and 2 had had tumor invasion into the main portal branches. Before treatment, 9 of the 12 survivors had been rated as Child's class A. Lipiodol was used in all 12 cases. The results of the present study suggest the usefulness of Lipiodol in treating advanced hepatocellular carcinoma.

Aged↗
PubMed1992

[Clinical usefulness of exercise/rest 99mTc-teboroxime SPECT imaging: results of a Japanese multi-center phase II study].

99mTc-Teboroxime [Chloro[tris(cyclohexyldioxime)methaneboronic acid] (99mTc)technetium], a perfusion agent for myocardial imaging, has a distinct advantage over 201Tl because of its very high myocardial extraction and is a 99mTc compound ideal for gamma camera imaging. This agent also demonstrates rapid myocardial washout, which allows completion of exercise and rest imaging studies in a short interval (to 1 hour). However, the rapid washout necessitates the completion of image acquisition very quickly after injection and therefore may require nonconventional SPECT imaging. In this Phase II study we evaluate the safety and efficacy of 99mTc-Teboroxime to detect coronary artery disease by exercise and rest SPECT imaging in 38 patients with prior myocardial infarction, 31 patients with angina pectoris, and 4 patients with non-coronary cardiac diseases. The 99mTc-Teboroxime dose used was 370-740 MBq in each study. The findings were compared with coronary angiography or 201Tl exercise and redistribution SPECT. No significant adverse reactions or laboratory abnormalities attributable to 99mTc-Teboroxime were observed. The quality of SPECT images was optimal in 62.5% of all patients. The relatively large population of suboptimal cases (37.5%) was attributed to the delay of the start and prolongation of the image acquisition time. In 85.7% of patients whose imaging was started within 5 minutes and completed within 11 minutes after injection, optimal quality was observed. Thus, 99mTc-Teboroxime SPECT requires the rapid completion of image acquisition after injection to achieve optimal image quality. Abnormalities of 99mTc-Teboroxime distribution were detected in 97.1% and 62.1% of patients with prior myocardial infarction or angina pectoris, respectively. The concordance with coronary angiography was 84.4% and 68.0%, and with 201Tl was 78.1% and 74.1%, respectively. Although standardization of the image protocol suitable for this agent is needed for the next study, these high correlations suggest the potential usefulness of 99mTc-Teboroxime SPECT imaging.

Adult↗
PubMed1992

[Diagnostic value of a new myocardial perfusion agent, 99mTc-teboroxime (SQ30,217) in patients with coronary artery disease, utilizing a SPECT imaging protocol: a multicenter phase III clinical trial].

Technetium-99m teboroxime (TEBO) is a new technetium-based myocardial perfusion imaging agent, which has high myocardial extraction and rapid myocardial washout. Its rapid myocardial washout may necessitate rapid imaging protocols. This study was designed to perform exercise/rest SPECT imaging protocols with rapid data acquisition (from 2.8 +/- 1.4 min to 11.2 +/- 4.1 min after injection) in 171 patients with coronary artery disease, 15 patients with cardiomyopathy and 8 patients with other heart disease. The rapid imaging protocols resulted in a high prevalence of good image quality. The diagnostic value of TEBO was recognized from the high concordance of image findings with thallium-201 (201Tl) scintigraphy, 88.2% in the exercise protocol and 89.9% in the rest protocol. Also, the sensitivity and specificity of TEBO for detecting coronary artery disease were comparable (86.6% and 53.9%, respectively) with those of 201Tl (90.7% and 46.2%, respectively). No toxic effects of TEBO were observed in subjective and objective clinical findings and blood examinations. TEBO was finally evaluated to be useful in 98.4% of the patients. Thus, this agent has good clinical potential for myocardial perfusion imaging.

Aged↗
PubMed1992

Diagnostic value of technetium-99m radionuclide angiography for detecting thrombosis in left atrial appendage.

In mitral valve disease, it is important to know whether thrombi are present in the left atrium when deciding upon a course of treatment. The left atrial thrombus usually locates in the left atrial appendage. In most cases of mitral valve disease, the left atrial appendage is clearly demonstrated by radionuclide angiography using 99mTc-labeled red blood cells and it can be speculated that the cases in which left atrial appendage are not demonstrated by RNA have left atrial thrombi. On the basis of this hypothesis, the diagnostic accuracy of radionuclide angiography to detect left atrial thrombi was evaluated retrospectively in 60 patients with mitral valve disease who had undergone surgery. The sensitivity of first-pass and equilibrium radionuclide angiography to detect left atrial thrombi was 83% and 67%, the specificity 79% and 54%, and the accuracy 80% and 57%, respectively. Although there were two false-negative cases in which the left atrial thrombi did not locate in the appendage and 10 false-positive cases in which left atrial appendages were not dilated, the negative predictive value was so high that a clearly demonstrated left atrial appendage can be translated into the absence of left atrial thrombi.

Adult↗
PubMed1991

[Changes in the cartilaginous contour of Legg-Calvé-Perthes disease: calculation on T1-weighted MR images].

T1-weighted MR images of Legg-Calvé-Perthes disease (LCPD) were classified into three groups on the basis of radiographic stage, and morphological differentiation for staging was attempted. In the stage of fragmentation, both enlargement and flattening of the cartilaginous contour surrounding the epiphysis could be recognized on MRI, and the growth plate showed more curvature than normal. This produced flattening of the epiphysis in the shape of a crescent. We confirmed these findings using four indexes for the measurement of cartilaginous outline, and the stage of avascular necrosis and fragmentation could be clearly differentiated. Cartilaginous deformities on MRI are very useful for differentiating between the stage of avascular necrosis and fragmentation.

Cartilage, Articular↗
PubMed1991

Regional distribution of the cells expressing glycine receptor beta subunit mRNA in the rat brain.

The expression of mRNA of the beta subunit of the glycine receptor was investigated in the rat by in situ hybridization histochemistry using an oligonucleotide probe specific to the sequence of the beta subunit. Neurons expressing beta subunit mRNA were widely and abundantly distributed in the rat brain from the olfactory bulb to the spinal cord. The pattern of distribution of cells containing beta subunit mRNA in the lower brainstem was very similar to that of cells containing alpha 1 subunit mRNA. In addition, beta subunit mRNA was strongly expressed by the neurons of the cerebral cortex, hippocampal formation and diencephalon as well as by the Purkinje cells where alpha 1 subunit mRNA expression is rare. These findings indicated that the glycine receptor is heterogeneous. The sites where strong labeling was noted were as follows. In the forebrain and diencephalon, strongly labeled neurons were abundant in the olfactory region, hippocampal formation, cerebral cortex, and thalamus. In the hippocampal formation, neurons in the subiculum, pyramidal cells in Ammon's horn, and neurons in the polymorphic layer of the dentate gyrus were strongly labeled. In the thalamus, the anterodorsal, reticular, parafascicular, and the subthalamic nuclei were strongly labeled. In the brainstem, the red nucleus, almost all of the motor neurons in the cranial motor nuclei innervating striated muscles, the trigeminal mesencephalic nucleus, the ventral tegmental nucleus of Gudden, and the pontine nucleus were strongly labeled. In the cerebellum, Purkinje cells in the Purkinje cell layer and all of the cerebellar nuclei were strongly labeled.

Animals↗
PubMed1991

[MR imaging of osteoradionecrosis of the mandibula following radiotherapy for head and neck cancers].

Magnetic resonance (MR) images of 13 patients with osteoradionecrosis of the mandibula were analyzed. Abnormalities were noted in all patients and could be classified into three groups. In nine patients, MR signals were homogeneously low in intensity on both T1 weighted images (T1WI) and T2 weighted images (T2WI), suggesting fibrosis of bone marrow. These nine patients had suffered radiologically and/or clinically overt osteoradionecrosis more than ten months previously, and inflammatory symptoms had settled down by the time of MR study. Two patients showed low signal intensity on T1WI and an area of inhomogeneous high intensity in a diffuse area of low signal intensity on T2WI, suggesting acute inflammation in the irradiated fibrous bone marrow. Both patients suffered pathologic fracture due to osteoradionecrosis and showed severe inflammatory symptoms at the time MR study. In one of the two patients, these pathologic changes were confirmed in surgically excised mandibulectomy specimens. The other two patients showed homogeneous low signal intensity on T1WI and high signal intensity on T2WI, a finding that may be due to slight inflammation. However, in one of the two patients, this signal feature possibly indicated loose fibrosis with marked cellularity.

Adult↗
PubMed1991

[Chest radiograph of foreign bodies in the tracheobronchial tree].

Chest radiographs in 14 children with foreign bodies in the tracheobronchial trees were evaluated retrospectively. The most common causative materials were nuts, and both main bronchi were most commonly involved. The initial chest radiographs that were used for analysis were obtained one hour to 50 days after aspiration or onset of symptoms. Of the nine cases in which chest radiographs were taken within 7 hours after aspiration, six showed hyperlucency with (three cases) or without overinflation (three cases) in the affected lungs, and the other three showed normal chest radiographs. Two patients had indeterminate diagnoses on chest radiographs at inspiration: one patient underwent chest radiographs at expiration and the other underwent fluoroscopy. Air-trapping was demonstrated in both patients. Of another five cases in which chest radiographs were taken 18 hours after aspiration of a foreign body, three cases showed atelectasis or consolidation and the other two showed hyperlucent lung. From these observations, hyperlucent lung indicates an early stage of the disorder while atelectasis or consolidation indicates a fairly advanced stage. In patients with clinically suspected foreign bodies, we advocate that additional examinations be performed to establish a final diagnosis, even when chest radiographs are normal or indeterminate.

Bronchi↗
PubMed1991

[MRI evaluation of the patellar articular cartilage in patients with subluxation of the patella].

In patients with subluxation of the patella, injury of the patellar articular cartilage is frequently observed and correct evaluation is important to manage these patients. We examined 11 patients with subluxation of the patella and five normal volunteers. In 12 patellofemoral joints of seven patients with subluxation of the patella, the abnormalities observed on MRI were compared with those on arthroscopy and/or at operation. MRI was performed with a Magnetom 1.5 T (Siemens) using the round surface coil. Pulse sequences were SE (TR 400 ms/TE 19 ms), FLASH (TR 320 ms/TE 15 ms FA 90 degrees and 40 degrees), and SE (TR 2000 ms/TE 26, 70 ms). We analysed MR findings of the 12 abnormal joints and 10 normal joints according to the following classification of abnormalities observed on arthroscopy. (1) normal appearance (n = 3 joints), (2) softening and fibrillation (n = 6), (3) fragmentation (n = 3), and (4) erosion to bone (n = 0). In only one of the six cases with softening and fibrillation observed on arthroscopy, MRI could visualize the thickening of patellar articular cartilage, but in all three cases with fragmentation observed on arthroscopy, MRI could visualize the thin inhomogenous cartilage with irregular surface. The combination of SE (TR 400 ms/TE 19 ms) and FLASH (TR 320 ms/TE 15 ms FA 90 degrees) are extremely effective pulse sequence to detect the abnormalities of patellar articular cartilage. We conclude that MRI is a useful noninvasive method of detecting advanced changes in patellar articular cartilage.

Adolescent↗
PubMed1991

[Magneto-optical disk filing system for oral diagnostic reports and their synchronized images].

The rewritable and compact media of magneto-optical disk (MOD) is firstly applied to store medical images with spoken reporting. The MOD has multi-media function of communication and filing. Our system is optimized in terms of recording length of speech based upon our clinical research. The results will have influences over the future PACS. One of their examples is possibility of multimedia PACS with images, speeches and demographic data. Another example is prevention of dispersion of images which have no interpretations by radiologists. Our next step is to recognize filed speech in background processing for printing reports.

Optical Storage Devices↗
PubMed1991

[Dynamic MRI of hepatocellular carcinoma with portal vein tumor thrombus].

Dynamic MRI with injection of Gd-DTPA was performed in 7 patients with hepatocellular carcinoma associated with portal vein tumor thrombus. A portal vein tumor thrombus was clearly visualized as a low intense structure. The segment supplied with this portal vein shows high intensity, probably due to the decrease in portal blood flow and compensated arterial blood flow. A tumor itself, located in this segment, was shown as a low intense area. Thus dynamic MRI is a useful method for differentiating the tumor from the surrounding nontumorous tissue with decrease in portal flow.

Aged↗
PubMed1991

Limitation of transcatheter arterial chemoembolization using iodized oil for small hepatocellular carcinoma. A study in resected cases.

The radiologic and histologic findings are presented of the resection of 14 small hepatocellular carcinomas (HCC), less than 2 cm in maximum diameter, after transcatheter arterial chemoembolization (TCE) using iodized oil. The effect of TCE on small HCC depended on the morphologic type of the tumors. When no extracapsular invasion of tumor cells occurred, TCE was extremely effective against encapsulated tumors. However, in nine of the 14 resected specimens, viable tumor cells remained in or around the tumor. The authors suggest that small HCC are not always curable with TCE alone and that a multi-disciplinary approach is necessary for patients with small HCC.

Aged↗
PubMed1991

Modified epiphyseal index for MRI in Legg-Calve-Perthes disease (LCPD).

On radiographs flattening of the femoral head is evaluated by the Epiphyseal Index (EI). Using the ability of MRI to show articular cartilage and the physis clearly, we wish to propose the use of an Epiphyseal Index for MRI (EIM) and demonstrate the value in LCPD. Fifteen patients were examined using 1.5T MR scanner and T1-weighted coronal images were obtained. EIM was calculated as a ratio of height and width of cartilaginous contour surrounding epiphysis, and was compared between normal and the three radiographic stages. EIM of normal hips were ranged from 0.39 to 0.60 and had a tendency to decrease with increasing age. All cases of Stage 1 (avascular necrosis) were within the normal range (n = 4, mean = 0.51, SD = 0.045). EIM of Stage 2 (fragmentation, n = 15, mean = 0.31, SD = 0.055) were smaller than that of Stage 1. Stag 2 and 3 (residual, n = 12, mean = 0.31, SD = 0.077) could not be distinguished by EIM. EIM was useful to show the flattening of epiphysis with growth and very important for differentiation between Stage 1 and 2 LCPD.

Adolescent↗