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Biomedical subjects

A Uno

Publications and source records attributed to A Uno.

121 records · Page 7Linked to original sources
PubMedDate not supplied

Accuracy of liver puncture under US guidance: re-evaluation by microcomputer simulation model.

OBJECTIVE: To evaluate, using microcomputer simulation models, the degree of distortion of the puncture needle in sonograms used during a liver puncture under ultrasound guidance. METHODS: We made a simplified simulation model of the puncture needle passing through the abdominal wall to the target lesion in the liver (cases without ascites), and additionally through ascites between the abdominal wall and the liver (cases with ascites), to evaluate the degree of distortion of the puncture needle in the sonogram. We considered the thicknesses and sound velocities of the abdominal wall and the ascites fluid, as well as the puncture angle, on the degree of distortion. RESULTS: (1) Cases without ascites: The puncture needle displayed on sonogram shifted predominantly anteriorly with a displacement error between 6 mm forward and 1 mm backward and with an angular error between 2.2 degrees forward and 0.1 degree backward when the abdominal wall was muscular, and the pattern of distortion had an inverted S-shape. It was displayed predominantly posteriorly with a displacement error between 14 mm backward and 2 mm forward and with an angular error between 3.7 degrees backward and 1.2 degrees forward when the abdominal wall was fatty, and the pattern was S-shaped. Regardless of the composition of the abdominal wall, when the abdominal wall was thin, the more obtuse the puncture angle was, the larger the shift was, and when the abdominal wall was thick, the more acute the puncture angle was, the larger the shift was. (2) Cases with ascites: (a) Regardless of the quantity and sound velocity of the ascites, the puncture needle shifted predominantly anteriorly with a displacement error between 7 mm forward and 3 mm backward and with an angular error between 3.1 degrees forward and 1.9 degrees backward when the abdominal wall was muscular, and showed the inverted S-shaped pattern. In contrast, it shifted predominantly posteriorly with a displacement error between 17 mm backward and 5 mm forward and with an angular error between 3.7 degrees backward and 3.9 degrees forward when the abdominal wall was fatty, and showed the S-shaped pattern. (b) Regardless of the sound velocity of the ascites fluid and the composition of the abdominal wall, the shift of the puncture needle changed little with differing amounts of ascites. CONCLUSION: It is highly recommended that a liver puncture under US guidance be performed taking into account the pattern of distortion of the puncture needle in each situation.

Artifacts↗
PubMedDate not supplied

Color Doppler findings in small abdominal aneurysms.

Four cases of small abdominal aneurysms were assessed by color Doppler ultrasonography. The aneurysms demonstrated interesting and highly complicated internal hemodynamics, including a swirling blood flow pattern and/or a color mosaic pattern. These findings suggested the usefulness of color Doppler ultrasonography for obtaining details on internal hemodynamics, which cannot be obtained with other modalities, such as angiography or computed tomography (CT).

Adult↗
PubMedDate not supplied

Portal hypertension in children and young adults: sonographic and color Doppler findings.

Portal hypertension is a relatively uncommon pathologic condition in children and young adults in contrast with older adults. The aim of this study is to evaluate the utility of sonography and color Doppler sonography in the diagnosis of portal hypertension in children and young patients and to evaluate the sonographic pattern of each disease. We reviewed 25 such patients who were younger than 30 years old and obtained the following sonographic findings: (1) liver cirrhosis: (a) multiple intrahepatic venovenous shunts in patients with primary Budd-Chiari syndrome and (b) intrahepatic vascular narrowing and nodular coarse parenchymal texture, with multiple very-high-echo spots along the portal vein in patients with Wilson disease; (2) congenital hepatic fibrosis: marked and developed collaterals, wide periportal echogenic band, and a heterogeneous parenchymal texture comprised of multiple high echoes but without portal thrombus; and (3) extrahepatic portal thrombosis: invisible portal lumen except as an echogenic band. Sonography and color Doppler sonography are very useful in diagnosing these portal hypertensive diseases. However, there are no specific sonographic findings, and the role of sonography is limited to follow-up observation of associated secondary hepatobiliary changes in patients with congenital biliary atresia.

Adolescent↗
PubMedDate not supplied

Large extrahepatic portosystemic shunt without portal hypertension.

Extrahepatic portosystemic shunt usually occurs secondary to severe portal hypertension, and it is rare to encounter it in patients without portal hypertension. We report herein a large extrahepatic portosystemic shunt between the left gastric vein and left renal vein without portal hypertension in which color Doppler sonography was useful not only for detection but evaluation of the effect of embolization.

Embolization, Therapeutic↗
PubMedDate not supplied

Arthroscopic relationship of the axillary nerve to the shoulder joint capsule: an anatomic study.

Twelve right shoulders in fresh cadavers were dissected to determine the relation of the axillary nerve to the shoulder capsule and glenoid. Needles transfixed the nerve to the capsule and into the shoulder joint. Arthroscopy was performed to determine the location of the needles on the glenoid clock. The needles were then removed and the position of the shoulder changed to determine the effect on the position of the axillary nerve. The axillary nerve was held to the shoulder capsule with loose areolar tissue in the zone between 5 and 7 o'clock and was close to the glenoid in the neutral position, in extension, and in internal rotation. With shoulder abduction, external rotation, and perpendicular traction, the capsule became taut and the axillary nerve moved away from the glenoid. Abduction, external rotation, and perpendicular traction increase the zone of safety during arthroscopic anteroinferior capsulotomy adjacent to the glenoid between the 5 and 7 o'clock positions.

Aged↗
PubMedDate not supplied

Legg-Calvé-Perthes disease in the evolutionary period: comparison of magnetic resonance imaging with bone scintigraphy.

Magnetic resonance images (MRIs) and pinhole scintigraphs were obtained in 40 patients (40 hips) with Legg-Calvé-Perthes disease in the evolutionary phase, the mean age at onset of symptoms being 6 years 7 months. The correlation between the uptake of the pinhole scintigraphs and the signal intensity of MRIs was examined in reference to the extent of the involved femoral epiphysis. MRIs depicted the extent of the involved femoral epiphysis more clearly than did pinhole scintigraphs. The uptakes of the pinhole scintigraphs corresponded with high or normal intensity of T2-weighted images on MRI. The femoral epiphysis in the initial phase (in which the signal intensity of the lateral area of the epiphysis on T1-weighted coronal images was low or intermediate and high or unchanged on T2-weighted coronal images corresponded to the lateral column [recanalization] on the pinhole scintigraphs) suggested a low risk of subsequent deformity. MRI is a powerful new technique to evaluate the femoral epiphysis in Legg-Calvé-Perthes disease.

Adolescent↗
PubMedDate not supplied

Middle-latency responses of awake and anesthetized Japanese macaques.

The middle-latency response (MLR) of two Japanese macaques were investigated. In the awake state, the configuration of the MLR components showed two positive peaks: Pa and Pb. The latency and the configuration of Pa were very similar to those of humans. In the topographic recordings, the largest Pa amplitude was found from the vertex, or R1, which is 1 cm lateral to the vertex. In the anesthetic state, Pa and Pb gradually disappeared. This study shows that the MLR in awake Japanese macaques is similar to that in humans, and differs from that in cats. Therefore these awake monkeys are suitable as animal models of human MLR.

Acoustic Stimulation↗
PubMedDate not supplied

A new liquid material for embolization of arteriovenous malformations.

We have developed a liquid material for embolization of arteriovenous malformations that is a mixture of ethylene vinyl alcohol copolymer and metrizamide dissolved in dimethyl sulfoxide. Upon contact with blood, dimethyl sulfoxide rapidly diffuses into the blood and forms an ethylene vinyl alcohol copolymer elastic soft sponge that obstructs both the feeder and the nidus. The material, which is not adhesive, was used for embolization of three left cerebral arteriovenous malformations with satisfactory results.

Adolescent↗
PubMedDate not supplied

A ground-based animal model of space adaptation syndrome.

We examined the effect and aftereffect of acute or chronic load of hypergravity produced by an animal centrifuge, on pica (that is, kaolin intake) in the rat as an index of motion sickness. Although the degree of pica initially induced by acute or chronic hypergravity was not different, the rate of decline of increased kaolin intake over poststimulus days was different. Pica after a 1-h load of 2g decreased rapidly. On the other hand, pica lasted 3 days after a 48-h load of 2g. These findings suggest that the aftereffects of chronic hypergravity application on pica are due to motion sickness induced by readaptation to normal gravity, and they support our idea that after adaptation to a hypergravity environment, return and readaptation to the normal gravity can simulate exposure and adaptation to microgravity. We concluded that motion sickness in rats induced by the aftereffects of chronic hypergravity stimulation can be used as a ground-based animal model of space adaptation syndrome.

Animals↗