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Biomedical subjects

M Akisada

Publications and source records attributed to M Akisada.

At least 37 records · Page 2Linked to original sources
PubMed1990

The role of preoperative radiotherapy for invasive thymoma.

Six patients with large invasive thymomas were treated by preoperative irradiation with 12 to 20 Gy before total or partial resection of the tumor. The responses of these 6 thymomas were estimated on the chest radiograms as follows; complete response in 2 patients, partial response in 3 and no response in one. Although the clinical responses varied, the surgical specimens of all the tumors pronounced severe fibrosis, probably not related to irradiation, and necrotic foci with a few viable tumor cells. Total resection of the thymoma was performed in 3 patients and subtotal resection in 3. Adhered or involved surrounding tissues such as the pericardium, pleura and/or veins were also resected in most patients. Preoperative radiotherapy facilitated total or subtotal resection of the invasive thymoma mass by reducing the tumor volume.

Adult↗
PubMed1990

[MR imaging of the arm].

Thirty arms of healthy adults were studied with MR imaging using surface coil. Fine structures of the arm, such as muscular bundles, small vessels and nerves were clearly demonstrated. Deep fascia dividing muscular bundles appeared as high intensity on T1-weighed image due to fat deposition beneath the fascia. Aponeurosis is also flat sheet of densely arranged collagen fibers. With rather thicker layer of collagen fibers than fascia, aponeurosis appeared as low intensity sheet that was frequently demonstrated on MR images of the extremities.

Adult↗
PubMed1989

[Pulmonary infarction associated with bronchogenic carcinoma].

Pulmonary infarction may be associated with bronchogenic carcinoma. Radiopathological correlation was performed in four patients. There were two cases of squamous cell carcinoma, one case of adenocarcinoma and one case of large cell carcinoma. Infarcts in patients with squamous cell carcinoma were obscured on plain radiographs by a large primary tumor or atelectasis of the affected lobe. Infarcts in adenocarcinoma and large cell carcinoma were clearly demonstrated on plain radiographs; 1 to 2 cm in size, round or polygonal in shape, blurred in margin, and located at the periphery of the same lobe as the primary tumor. Rapid appearance of infarcts was helpful in distinguishing from intrapulmonary metastasis. Invasion of the pulmonary artery, pulmonary vein and bronchial wall in hilar region was thought to be responsible for pulmonary infarction. Pulmonary infarct should be considered in patients with centrally invasive bronchogenic carcinoma, when a small ill-defined opacity appears at the periphery of the involved lobe over a short period.

Aged↗
PubMed1989

[Field localization and verification system for proton beam radiotherapy in deep-seated tumors].

It has been recognized that, for precise localization and verification of radiation fields, a marking drawn on the skin surface is not entirely reliable because its position relative to bony structures or internal organs is not stationary. This is especially true when treating deep-seated tumors located below the clavicle. In proton beam radiotherapy at the University of Tsukuba, we ristrict the margins around the target volume. Therefore, special care in field localization and verification is needed, and we make it a rule to take X-ray pictures on each treatment day. To accomplish this, we have developed a localize-and-verify system by using fluoroscopic techniques and combining it with a real-time digital image processing device. This allows for the formation of a digital image of the proton field and storage it in the optic disc. By using this system as well as verification films, filed placement errors were measured in 10 patients with deep-seated tumors. Out of a total of 190 localizations, 22% exhibited a field placement error of more than 5 mm, where patient positioning and field localization were done by using skin drawings aligned with laser beams. This result strongly suggests the necessity for daily localization and verification of radiation fields, as is being done by us, for precision in the execution of proton beam radiation therapy.

Adult↗
PubMed1989

Intense accumulation of indium-111 leukocytes in peritonitis carcinomatosa.

In order to detect the infectious foci in a case of terminal recurrent cancer of the sigmoid colon with intense inflammation, In-111 oxine leukocyte scintigraphy was performed. Leukocytes labeled with In-111 oxine quickly localized within the region of peritonitis carcinomatosa and could be imaged after 4 hours. With time, high activity appeared in this area. And 48 hours after injection, the large intestine was clearly seen. However, no activity was seen in the main recurrent tumor. This suggested that the labeled leukocytes had accumulated in regions of inflammation rather than in malignant tissue. When performing In-111 leukocyte scintigraphy for diseases in which tumor cells and inflammation are mixed, distinguishing the two components is particularly important, and time-sequential scanning is very useful.

Adenocarcinoma, Papillary↗
PubMed1989

Ga-67 scintigraphy in chromomycosis.

We examined an interesting case of chromomycosis that had a characteristic Ga-67 accumulation. This patient had had widespread chromomycosis skin lesions for 8 years. We performed Ga-67 scintigraphy in an attempt to obtain additional information on the site and extent of the lesion. Ga-67 scintigraphy revealed not only all subcutaneous nodules but also an unsuspected enlarged lymphnode and a visceral lesion. This case indicates that Ga-67 scintigraphy is a very useful method to use in detecting the site and extension of chromomycosis, especially in the nodal and the visceral lesions, and sometimes might help in differential diagnosis.

Chromoblastomycosis↗
PubMed1989

An ultrasonographic method for detection of Achilles tendon xanthomas in familial hypercholesterolemia.

The diagnosis of familial hypercholesterolemia (FH) is frequently made on clinical grounds and detection of tendon xanthomas is crucial for that. In order to clarify whether ultrasonography (US) can be used as a reliable and practical method for detection of Achilles tendon xanthomas in FH, the Achilles tendon thickness in the sagittal section was examined by US in 15 patients with heterozygous FH and 34 normocholesterolemic subjects. US visualized clearly the anterior and posterior borders of the Achilles tendon. The Achilles tendon thickness determined by US correlated with that measured by conventional radiography (r = 0.99). The mean values +/- SD of the Achilles tendon thickness determined by US were 4.5 +/- 0.5 mm in the normal controls and 11.9 +/- 5.1 mm in the patients and the difference was significant (P less than 0.001). In 13 of 15 patients, US visualized thickened Achilles tendons with convex shape in the sagittal section. All the thickened Achilles tendons revealed by US were confirmed by radiography. The data indicate that US can detect Achilles tendons thickened by xanthomas. We conclude that US is a useful aid in the clinical diagnosis of FH.

Achilles Tendon↗
PubMed1989

Irradiation synchronized with respiration gate.

A respiratory gating technique was developed for radiotherapy of tumors unable to remain stable due to respiration. Irradiation was started and stopped with a microwave oscillator of a linear accelerator controlled by gating signals at specific points in the respiratory cycle. This technique was tested in a phantom specially designed to simulate a patient with lung cancer and in clinical therapy for lung tumors of seven patients. A mask was used to check ventilation in the phantom and airbags were used to measure thoracoabdominal pressure in patients and in the phantom; this enabled us to detect the excursion of the tumors. Low sensitivity film for verification demonstrated the efficacy of this technique. The gated irradiation was proved to ensure more precise radiotherapy for tumors located close to the diaphragm.

Humans↗
PubMed1989

Evaluation of myocardial perfusion abnormality by profile analysis for digital subtraction angiogram.

For quantitative estimation of ischemia, ECG-synchronized digital subtraction angiography was performed for selective coronary arteriography. The authors obtained sequential myocardial perfusion images at the arterial, capillary, and venous phases. Profile densitometry was performed along the cross section perpendicular to the long axis of the left ventricle to assess regional myocardial perfusion at the capillary phase quantitatively. By this densitometry, the volumes of vascular bed perfused by the left coronary artery could be estimated, and further, nontransmural myocardial infarction could be differentiated from transmural myocardial infarction through the profile of its density curve. This method appears to be useful for the analysis of myocardial perfusion of ischemic heart disease.

Adult↗
PubMed1989

[Analysis of patients surviving for six months after irradiation of a bone metastasis].

The effects of treatment of a bone metastasis have been studied in 49 patients who survived for more than six months after radiotherapy (RT). Relief from the symptoms reached a rate as high as 91% (85/93 irradiated sites) irrespective of the primary site of the cancer. However, the survival rate and the rate of symptom relief maintenance were statistically higher in those with breast cancer (15 patients, 38 irradiated sites) than in those with a lung cancer (15, 24). The local control rate was dose dependent (TDF). High-dose irradiation, therefore is recommended to achieve a high local control rate for patients with a long life expectancy.

Bone Neoplasms↗
PubMed1989

[MRI and ultrasonography of cavernous hemangioma of the liver].

The frequency of detection of hemangioma has increased with the improvements of ultrasonography. Sonography detected 24 lesions out of 30 (80%), and 28 lesions out of 30 (93%) by MRI. MRI is superior to ultrasonography in detection rate. In T2 weighted spin echo image, most of the hepatic hemangiomas show moderately or markedly higher intensity than the liver and mildly higher or the same intensity as that of the spleen. MRI will play an important role in determination of necessity of further invasive diagnostic methods such as angiography or biopsy.

Adult↗
PubMed1989

[The relationship between N-isopropyl-p-[123I]iodoamphetamine accumulation in the brain and its dynamics in other organs].

Single photon emission computed tomography of the brain and dynamic scintigraphy of the lung and liver with N-isopropyl-p-[123I]iodoamphetamine (IMP) were performed in 21 patients with and without cerebrovascular diseases to determine the relationship between IMP accumulation in the brain and its dynamics in other organs. The D/E ratios of the lung, liver and brain were calculated dividing the counts of the delayed image by that of the early image. The brain D/E ratio in the normal hemisphere was well correlated with the lung D/E ratio. So cases which showed more rapid lung washout tended to washout faster from the brain. We thought that this fact was affected by the systemic circulation. And the values of the brain D/E ratio of the cerebrovascular disease group were larger than that of the non-cerebrovascular disease group. This suggest the frequent existence of arteriosclerotic changes in patients of the cerebrovascular disease. Because the local brain washout was depended on the amount of the cerebral blood flow there. On the other hand, the lung D/E ratio was inversely correlated with the liver D/E ratio. In other words, more washout from the lung caused more accumulation of IMP in the liver. Also the brain D/E ratio was inversely correlated with the liver D/E ratio. In conclusion, there was a close relationship between IMP dynamics in the brain and that in other organs.

Adolescent↗
PubMed1989

Isoproterenol stress thallium scintigraphy for detecting coronary artery disease.

The value of exercise thallium scintigraphy in detecting coronary artery disease is well established. However, there are at times situations in which the exercise test cannot be readily used. Isoproterenol (ISP) stress ECG (ISP-ECG) is reportedly a useful method in diagnosing coronary artery disease. In the present study, we assessed the diagnostic value of ISP thallium scintigraphy, comparing it with those of ISP-ECG and exercise thallium scintigraphy. The study population consisted of 24 patients who had histories of chest pain without previous myocardial infarction. ISP was given at increasing doses of 0.02, 0.04, 0.08 micrograms/kg/min at 3-minute intervals, and was terminated for any of the following reasons: angina, significant arrhythmia, significant ST segment depression (greater than or equal to 0.1 mV) or target heart rate. Thallium scintigrams were obtained immediately after terminating ISP infusion, and after a 3-hour delay, redistribution scans were obtained. Scintigrams were considered positive when a reversible defect was present. In nine patients who underwent exercise tests, exercise thallium scintigraphy was also performed. After the stress tests, coronary angiography was performed. According to the presence or absence of significant coronary artery stenosis (greater than or equal to 75%), all subjects were divided into two groups: coronary artery disease (CAD) group (n = 12) and so-called normal coronary (NC) group (n = 12). 1. Among 12 patients in the CAD group, ISP induced anginal pain in six (50%), and ISP-ECG and ISP thallium scintigraphy were positive in 10 (83%) and in 11 (92%), compared with four (33%), four (33%) and two (17%) in the NC group.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1989

[Quantitative evaluations of left ventricular function obtained by electrocardiographically-gated magnetic resonance imaging].

Using electrocardiographically-gated magnetic resonance imaging, regional cardiac function was evaluated in 12 normal volunteers and in 10 cases of old myocardial infarction. The optimal short axis of the left ventricle was selected at the chordae tendineae level. The left ventricle was divided into 12 segments using a computer-aided system, and percentile shortening fraction (%SF) and percentile wall thickening (%WT) were calculated in each segment by the fixed coordinate method. In the normal volunteers, heterogeneity of both %FS and %WT was observed, ranging from 25 +/- 13% and 37 +/- 13%, respectively in the septal segment, to 49 +/- 13% and 60 +/- 21%, respectively in the posterior segment. In the cases of myocardial infarction, decreased %FS and %WT were detected at the affected regions. The abnormal regions revealed by %WT tended to be narrower than those revealed by %FS. Thus the MR technique at the optimal axis may be useful for quantitative evaluations of regional cardiac function.

Adult↗
PubMed1989

[Bone dynamic study--evaluation for factor analysis of hip joint].

Factor analysis was applied to dynamic study of Tc-99m MDP for the evaluation of hip joint disorders. Fifteen patients were examined; eight were normal, six were osteoarthritis in which one accompanied synovitis was included, and one was aseptic necrosis on the head of the femur. In normals, according to the Tc-99m MDP kinetics, three factor images and time-activity curves were obtained which were named as blood vessel, soft tissue, and bone factor images and curves. In the patient with osteoarthritis, increased accumulation of the hip joint was shown in bone factor image only. But in one patient, who took osteoarthritis with synovitis, marked accumulations of the Tc-99m MDP appeared not only on the bone factor image but also on the soft tissue. Operation revealed thickening synovial tissue around the hip joint, caused by inflammatory process. In follow-up studies of the patient with aseptic necrosis on the head of the left femur, excessive accumulations, which were seemed in his left hip joint on both bone and soft tissue factor images at first, were decreased respondently to the treatment of this lesion. In conclusion, the factor analysis was useful for differencial diagnosis of the hip joint disorders and observation of the clinical course of the hip joint disorders.

Adult↗
PubMed1989

[Clinical evaluation of indium-111-labeled leukocyte imaging in bone infection].

In-111-oxine-labeled leukocyte imaging was performed on twenty-one patients suspected of having bone infection. Nine of eleven cases (82%) were diagnosed as having active infection as demonstrated by abnormal accumulation of In-111-labeled leukocytes at the site of infection. There are two false negative (18%) cases. Two cases without active infection showed abnormal uptake. Four cases revealed cold defects on the scintigraphy. Marked uptake of radiotracer was noted not only in the case of acute osteomyelitis with acute septicaemia but also in the case with persistent chronic active osteomyelitis. It was observed that for precise evaluation of the test results it was equally important to compare the imaging findings with physical signs and laboratory investigations. It is concluded that In-111-oxine-labeled leukocyte imaging is a useful tool for the evaluation of the progression of bone infection.

Adult↗