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Biomedical subjects

N Matsunaga

Publications and source records attributed to N Matsunaga.

At least 19 recordsLinked to original sources
PubMed1995

Regional ventilatory evaluation using dynamic SPET imaging of xenon-133 washout in obstructive lung disease: an initial study.

Regional ventilatory abnormalities in obstructive lung disease were evaluated by dynamic single-photon emission tomography (SPET) of pulmonary washout of xenon-133 (133Xe) gas. The subjects included seven healthy volunteers. 17 patients with obstructive lung disease, and seven patients with restrictive lung disease. Following 6 min of inhalation of 133Xe gas (60-72 MBq/l), equilibrium and subsequent washout SPET images during spontaneous breathing were sequentially acquired every 30 s for 6-7 min, using a triple-head SPET system with the return mode of continuous repetitive rotating acquisition. A gravity-induced gradient of ventilation was demonstrated in the volunteers' lungs. Compared with the normal subjects, all the patients with obstructive disease showed abnormal 133Xe retention on the washout SPET images, with or without abnormalities on chest X-ray computed tomography, whereas the patients with restrictive disease did not show any significant delays in washout. This modality may assist in the evaluation of the three-dimensional dynamic process of ventilatory abnormalities in obstructive lung disease.

Adult↗
PubMed1995

Enhanced MR imaging of the liver after ethanol treatment of hepatocellular carcinoma: evaluation of areas of hyperperfusion adjacent to the tumor.

OBJECTIVE: In the arterial phase of dynamic contrast-enhanced MR images, we observed areas of increased contrast enhancement adjacent to hepatocellular carcinomas treated by percutaneous ethanol injection. The purpose of this study was to assess the frequency, appearance, and location of this hyperperfusion abnormality. It is important not to mistake this finding for other pathologic conditions. SUBJECTS AND METHODS: Multisection dynamic MR images obtained in 33 consecutive patients with hepatocellular carcinoma treated with percutaneous ethanol injection were reviewed. Hepatic parenchymal hyperperfusion abnormalities were diagnosed when areas of early enhancement were seen in the hepatic parenchyma adjacent to the treated tumor. The location, appearance, and frequency of the findings were recorded. RESULTS: Hepatic parenchymal hyperperfusion abnormalities were observed in 15 (45%) of the 33 patients on arterial-dominant-phase images. Of these 15 patients, 10 (67%) had MR imaging within 1 month after percutaneous ethanol injection. Hyperperfusion abnormalities were located in liver parenchyma adjacent to the lesion with wedge-shaped appearances. In two patients, early opacification of the peripheral portal branch was seen within the area of hyperperfusion abnormalities. CONCLUSION: Hepatic hyperperfusion abnormalities are commonly seen adjacent to a treated hepatocellular carcinoma on contrast-enhanced MR images. Awareness of this hyperperfusion abnormality, which is caused by increased blood flow after percutaneous ethanol injection, is important because such a finding may be misinterpreted as another pathologic condition such as tumor progression or tumor thrombosis of the portal vein branches.

Adult↗
PubMed1995

Bone scintigraphy in growth hormone-secreting pulmonary cancer and hypertrophic osteoarthropathy.

Hypertrophic osteoarthropathy was detected in a 55-yr-old man with pulmonary squamous-cell cancer by bone scintigraphy using 99mTc-hydroxy methylene diphosphonate (HMDP). Intense symmetrical uptake was demonstrated in the distal portions of the long bones as was the parallel tract sign, accompanied by markedly elevated serum growth hormone levels. After chemoradiotherapy for pulmonary cancer, the arthralgia disappeared and scintigraphic findings and serum growth hormone levels improved, suggesting that ectopic production of growth hormone in the pulmonary tumor had been associated with hypertrophic osteoarthropathy. These findings indicate that bone scintigraphy is useful for detecting hypertrophic osteoarthropathy, and assessing alterations in hypertrophic osteoarthropathy activity post-treatment.

Bone and Bones↗
PubMed1995

[Evaluation of regional pulmonary 133Xe-gas washout with dynamic SPECT imaging obtained by a triple-headed SPECT system with continuous repetitive rotating acquisition mode].

The clinical potential of the dynamic SPECT in studying pulmonary washout of Xenon-133 (133Xe), using a triple-headed SPECT system (Toshiba GCA 9300A/HG, Japan) with continuous repetitive rotating acquisition mode, was preliminarily investigated in 6 healthy volunteers and 23 patients with various lung diseases. The equilibrium image was initially acquired for 1 min after breathing 133Xe gas (370 MBq) in a closed circuit for 6 min, and subsequently serial 133Xe-washout SPECT images were continuously acquired every 60 sec for 5-6 min. As the ventilation index, the real half time of regional activity was evaluated. The SPECT study demonstrated the gravity-induced gradient on ventilation in the normal subjects. In the various lung diseases, it allowed us to demonstrate visually and quantitatively the dynamic process and three-dimensional distribution of ventilation abnormalities, with or without chest radiographic abnormalities. These results indicate clinical potential of pulmonary dynamic SPECT of 133Xe-washout for elucidating the distribution and nature of ventilation abnormalities in various lung diseases.

Adult↗
PubMed1994

[Regional pulmonary Xenon-133 washout study using dynamic SPECT images obtained by a triple-headed SPECT system].

We investigated preliminary the clinical utility of dynamic SPECT in studying pulmonary Xenon-133 gas washout, using the continuous repetitive rotating acquisition method with a triple-headed SPECT system. The subjects included one healthy volunteer and 16 various lung diseases. After obtaining the equilibrium images, the sequential washout images were acquired every 60 sec for 6 min. As the ventilation index, the real half-time of regional activity was evaluated. With or without abnormalities on chest CT, these images allowed us to show effectively the three-dimensional distribution of ventilation abnormalities, such as peripheral or segmental air trapping.

Humans↗
PubMed1994

Atypical appearance of adrenal pseudocysts.

We report 2 cases of adrenal pseudocysts that resulted from hemorrhage into a normal adrenal gland and that showed atypical imaging features on computerized tomography and ultrasonography. The presence of a solid component within the mass and/or central calcification, which is unlike the typical features of adrenal pseudocyst, suggested a diagnosis of adrenal tumor. The solid component diminished on computerized tomography in 26 days in case 1 and in 16 days in case 2, which seemed to represent resolving hematoma. The atypical appearance of these adrenal pseudocysts, especially the changeable pattern of the solid component within the mass, should be kept in mind to ensure a correct preoperative diagnosis.

Adrenal Gland Diseases↗
PubMed1994

Aortic dissection caused by angiographic procedures.

PURPOSE: To describe findings in, and the clinical course and outcome of, aortic dissection (dissecting aneurysm) caused by angiographic procedures. MATERIALS AND METHODS: The records of approximately 15,500 angiographic procedures performed between 1985 and 1991 were reviewed. In the six cases of iatrogenic aortic dissection identified, computed tomography (CT) was performed for diagnosis, follow-up, or both. RESULTS: The type of aortic dissection was Stanford type A in three patients and Stanford type B in three patients. The sites of injury were the abdominal aorta (n = 2), right brachiocephalic artery (n = 2), middle of the thoracic aorta (n = 1), and right common iliac artery (n = 1). One patient had anterograde dissection from the site of injury; two patients, retrograde dissection; and three patients, extensive dissection that extended in both anterograde and retrograde directions. Retrograde dissections decreased in size or disappeared in 1-3 months due to the absence of reentry, whereas anterograde dissections persisted during follow-up (15-27 months). All patient were treated without surgery. CONCLUSION: Angiographers should be aware of this potentially serious complication. The extent and type of the aortic dissection can be determined with CT.

Aged↗
PubMed1994

Multiple intrahepatic aneurysms following transcatheter arterial embolization. Work in progress.

PURPOSE: To discuss the mechanism of multiple intrahepatic aneurysm formation after transcatheter arterial embolization (TAE) performed in five patients with hepatocellular carcinoma. MATERIALS AND METHODS: TAE was performed with gelatin sponge particles and iodized oil as embolic materials. Mitomycin C was also used in four cases. RESULTS: Three to 14 aneurysms 1-6 mm in diameter were found in third-to sixth-order branches of the hepatic arteries at repeat angiography performed 25-45 days after TAE. Follow-up angiograms in three cases revealed that most aneurysms were no longer apparent except in one patient in whom two aneurysms remained and were larger than before. In none of the five cases were any signs of aneurysm rupture noted. CONCLUSION: Radiologists should be aware of this complication of TAE. It is speculated that the main cause of aneurysm formation in these patients was the embolic agents used.

Aneurysm↗
PubMed1994

Case report: ciliated foregut cyst of the pancreas mimicking teratomatous tumour.

A ciliated cyst of foregut origin is often found in relation to the tracheobronchial tree and the upper gastrointestinal tract, when it is called bronchogenic cyst and enterogenous cyst, respectively. Cysts of this type rarely occur in the pancreas. We report a case of ciliated foregut cyst involving the pancreas, and mimicking teratomatous tumour on radiology.

Adult↗
PubMed1994

Cine-magnetic resonance imaging of cor triatriatum.

Two adult patients with cor triatriatum, which was shown by echocardiography and magnetic resonance imaging (MRI) using both spin-echo and cine-MR techniques, are presented. Spin-echo MRI clearly demonstrated an anatomical relationship between the membrane and pulmonary veins or left atrial appendage, which was not clear on transthoracic echocardiography. In addition, cine-MRI depicted abnormal flow through the fenestration of the anomalous membrane (case 1 and 2) and shunted flow through the associated atrial septal defect (case 2).

Adult↗
PubMed1993

[CT findings of invaginated mesentery in adult intussusception].

The CT findings of invaginated mesentery in adult intussusception were analyzed in 12 patients (three patients with four small bowel intussusceptions and nine patients with nine large bowel intussusceptions). In all small bowel intussusceptions, the neck was located near the superior mesenteric artery and vein (SMA & SMV) and showed a medial opening, and the vessels in the neck showed a continuity to the left side of SMA & SMV. In most of the large bowel intussusceptions, the neck was located distant from SMA & SMV, and the vessels in the neck did not show continuity to SMA & SMV. The difference in CT findings between small and large bowel intussusception is attributed to the difference in mesenteric anatomy; the small bowel and its mesentery move freely in the peritoneal cavity, whereas the large bowel is partially fixed to the retroperitoneum.

Adult↗
PubMed1993

Coronary-to-pulmonary artery shunts via the bronchial artery: analysis of cineangiographic studies.

Coronary-to-pulmonary artery shunts via the bronchial artery (CA-BA-PA shunts) were observed in 16 of 2,922 consecutive patients who underwent selective coronary cineangiography. Underlying diseases included Takayasu arteritis (n = 8), chronic pulmonary inflammatory diseases (n = 4), pulmonary thromboembolism (n = 2), pulmonary artery tumor (n = 1), and tetralogy of Fallot with pulmonary atresia (n = 1). Ventilation-perfusion scans were available in 15 of the 16 patients. Mismatched defects were identified in 11 patients, and matched defects were identified in four. Bronchial-to-pulmonary artery shunts were detected on selective bronchial angiograms and/or thoracic aortograms in 13 patients. Feeding arteries of the CA-BA-PA shunts included left atrial branches (n = 13), right sinus node branches (n = 7), left sinus node branches (n = 2), right conal branch (n = 1), left conal branch (n = 1), and posterolateral branches (n = 2). These coronary branches seemed to serve as collateral vessels from a coronary arterial system with a higher pressure to a pulmonary arterial system with a lower pressure in conditions of decreased pulmonary flow or in cases of chronic pulmonary inflammatory disease. The importance of the coronary artery along with other superior thoracic collateral networks in contributing to the development of shunts to the pulmonary artery is underscored.

Adult↗
PubMed1993

Denervated skeletal muscle: MR imaging. Work in progress.

PURPOSE: To evaluate the change in signal intensity of skeletal muscles after denervation and to determine the clinical usefulness of magnetic resonance (MR) imaging in diagnosis of denervation. MATERIALS AND METHODS: Denervated skeletal muscles associated with various forms of peripheral neuropathy and spinal radiculopathy were studied with MR imaging in 17 patients. RESULTS: On T1-weighted images, signal intensity of denervated muscles was normal in 14 patients and high in three. On T2-weighted images, all denervated muscles showed high signal intensity on at least one MR image. High signal intensity in the denervated muscles on T2-weighted images was observed 15 or more days after onset of paralysis. In two patients, signal intensity of denervated muscles returned to normal after relief of paralysis. CONCLUSION: MR imaging is a noninvasive and accurate method for use in diagnosis of denervation and may ultimately eliminate the need for electromyography.

Adipose Tissue↗
PubMed1993

Inhibitory effect of volatile fatty acids on GRF-induced GH secretion in sheep.

The effect of intravenous infusion of acetate, propionate and butyrate (0, 3, 10, 30 mumol kg-1 min-1 over 40 min) on the secretion of growth hormone (GH), insulin and glucagon in response to growth hormone-releasing factor (GRF) injection (0.25 micrograms/kg, 10 min after the onset of acid infusion) was determined in six sheep. The intravenous injection of GRF caused a marked increase in plasma GH at every dose of each acid. The GH response to GRF was unaffected by an intravenous infusion of acetate. The basal plasma levels of insulin, glucagon and glucose were unchanged by acetate infusion. The infusion of propionate markedly suppressed the GH response to GRF in a dose-dependent manner. Propionate produced increases in plasma insulin, glucagon and glucose concentrations. Butyrate infusion also caused a significant attenuation of GRF-induced GH secretion. Butyrate infusion stimulated the secretion of both insulin and glucagon and caused hyperglycemia. After cessation of the infusion of propionate or butyrate plasma GH tended to increase again. Plasma somatostatin concentrations, which were measured only for the highest dose of butyrate, were unchanged during acid infusion, but increased on discontinuing the infusion. It is concluded that propionate and butyrate suppress GH secretion, while stimulating the secretion of insulin and glucagon in sheep.

Acetates↗