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31.
Magnetic resonance (MR) imaging was performed at 29 weeks of pregnancy after ultrasonographic detection of an abnormal cleft in the fetal brain. Fetal neuromuscular blockade was induced by pancuronium bromide injected into the umbilical vein under continuous ultrasound (US) guidance. MR images supported the echotomographic diagnosis of schizencephaly improving the visualization of symmetrical broad clefts connecting the lateral ventricles with the subarachnoid space. Schizencephaly was finally confirmed by neonatal US, computed tomography, and MR. 相似文献
32.
F. Daffos F. Forestier J. Mac Aleese C. Aufrant L. Mandelbrot E. A. Cabanis M. T. Iba-Zizen J. M. Alfonso J. Tamraz 《黑龙江环境通报》1988,8(4):311-314
Fetal magnetic resonance (MR) imaging was performed at 33 weeks of gestation for investigation of a posterior fossa abnormality found at ultrasound screening. Fetal movements were abolished by vecuronium injected under ultrasound guidance into the umbilical vein. MR images showed atrophy of the left cerebellar lobe with cisternal dilatation. These were confirmed postnatally by CT scan. 相似文献
33.
Ravi Bhargava Dr D. Ian Hammond Ronald J. Benzie E. Carlos G. Ventureyra Michael J. Higgins David J. Martin 《黑龙江环境通报》1992,12(8):653-659
Myelocystocele is a rare spinal cord disorder and has not been described prenatally. We report a case in which prenatal ultrasound and magnetic resonance imaging (MRI) demonstrated a posterior cervical mass which was initially thought to be a meningocele or an atypical cystic hygroma. Surgery performed at 1 day of age showed this to be a myelocystocele. Therefore, the differential diagnosis of an extracranial cystic mass in the posterior cervical region should be expanded to include myelocystoceles. 相似文献
34.
Cinzia Zoppini Angelo Vanzulli Alessandra Kustermann Tommaso Rizzuti Angelo Selicorni Umberto Nicolini 《黑龙江环境通报》1993,13(10):995-999
Omphalopagus conjoined twins were diagnosed by ultrasonography in a pregnant woman at 21 weeks' gestation. In order to clarify the anatomical connections, magnetic resonance imaging (MRI) was performed, having achieved fetal paralysis by intravascular injection of 100 mg of pancuronium into each twin. Prior to MRI, 2 ml of a 0.0001 mmol/ml solution of gadolinium DTPA was also injected into the stomach of one twin. The contrast agent opacified the bowel loops of both twins, indicating bowel to bowel anastomosis. Following pregnancy termination, autopsy confirmed the prenatal diagnosis. 相似文献
35.
Ultrasonic experiments were undertaken on CO2 flooded sandstone core samples, both synthetic sandstones and core plugs from the CRC1 CO2 injection well in the Otway Basin, Victoria, South Eastern. Australia. The aim of these laboratory tests was to investigate the effects of CO2 as a pore fluid on the seismo-acoustic response of the sandstone and ultimately to provide an indication of the sensitivity of time-lapse seismic imaging of the eventual CO2/CH4 plume in the Otway, Waarre C formation.The synthetic sandstones were manufactured using both a proprietary calcium in situ precipitation (CIPS) process and a silica cementing technique. Samples were tested in a computer controlled triaxial pressure cell where pore pressures can be controlled independently of the confining pressures. The pressure cell is equipped with ultrasonic transducers housed in the loading platens. Consequently, effective pressures equivalent to those expected in the reservoir can be applied while ultrasonic testing is undertaken. Both compressional, P and shear waves, S were recorded via a digital oscilloscope at a range of effective pressure steps. Pore pressures were varied from 4 MPa to 17 MPa to represent both the gaseous and liquid phase regions of the CO2 phase diagram. Similar experiments were conducted on core plugs from the Waarre C reservoir horizon obtained from the CRC1 injection well, but with an intervening brine-saturated step and in some cases with a CO2/CH4 mix of 80%/20% molar fraction which is representative of the field situation. However, the pore pressure in these experiments was held at 4 MPa. Finally, acoustic impedances and reflection coefficients were calculated for the reservoir using Gassmann theory and the implications for imaging the CO2 plume is discussed. 相似文献
36.
Occupational exposure to radiofrequency (RF) and static magnetic fields at magnetic resonance imaging (MRI) suites is of continuing
concern to personnel who routinely work in this environment. Questions regarding the levels of occupational RF and static
field exposure have increased with the increasing demand for anesthetics to be administered in this environment. The present
study was thus designed towards addressing the above-mentioned problem by gaining information regarding exposure levels of
clinical personnel at MRI units in South Africa. Three 1.5 MRI units in Bloemfontein, South Africa were utilized to evaluate
the exposure of clinical personnel to the electromagnetic fields present in the MRI environment over a period of time and
during different clinical MRI procedures. Three rounds of measurements of RF fields in the MRI environment were done. All
the three measurement rounds were focused on the low frequencies, 5 Hz–32 kHz, as well as on the high frequencies, 300 kHz–40 GHz.
First round measurements were done to establish the background of the RF fields in and around the magnet room during an MRI
examination. Second round RF field measurements were done at a specific location, 1 m away from the bore on the right-hand
side of the bed, in the MRI room. The third round measurements were of the same format as the second round, but the specific
location was against the magnet bore. Two pieces of Narda Safety Test Solution instruments, the EFA-300 and EMR-300, were
used to measure the electromagnetic and magnetic exposure fields generated from the MRI scanners. Results of the measurements
indicate that the electromagnetic fields measured during different clinical procedures do not exceed the International Commission
on Non-Ionizing Radiation Protection (2000) guidelines in these units. Results from round two and three showed that the RF
and gradient exposure 1 m and up against the bore entrance does not exceed these guidelines (rms average over 6 min). Ongoing
new developments in MRI scanning create the need for continuously monitoring exposure of patients and workers to the EMF fields
in the MRI environment. 相似文献
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39.
大气气溶胶对人体健康环境和全球气候都有一定的影响,是大气污染的主要来源。为了提升空气质量,大气污染防治刻不容缓。把气溶胶探测激光雷达和测风激光雷达集成在车辆上,进行走航和扫描探测可获得立体的大气气溶胶时空变化状态图。以合肥和芜湖等地大气气溶胶探测为例,基于激光雷达走航车的探测数据,获得大气气溶胶消光系数时空分布图,搜寻污染物排放源和估算颗粒物的PM2.5输送通量。由此可知,激光雷达走航式探测技术是获得大气污染立体图像便捷的、有效的方法,可为大气污染防治提供精准的科学依据,具有重要的应用价值。 相似文献
40.