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41.
Justin W. Phillpott M.D. Leonard E. Swischuk M.D. Susan D. John M.D. 《Emergency radiology》1997,4(2):68-71
We reviewed plain radiographs of 215 pediatric patients with surgically proven appendicitis to study the value of plain radiography for diagnosis. 相似文献
42.
Camilla Nyboe Jonas A. Funder Morten H. Smerup Hans Nygaard J. Michael Hasenkam 《European journal of cardio-thoracic surgery》2006,29(6):1008-1013
Objective: Mechanical heart valves can cause thromboembolic complications, possibly due to abnormal flow patterns that produce turbulence downstream of the valve. The objective of this study was to investigate whether three different bileaflet valve designs would exhibit clinically relevant differences in downstream turbulent stresses. Methods: Three bileaflet mechanical heart valves (Medtronic Advantage®, CarboMedics© Orbis™ Universal and St. Jude Medical® Standard) were implanted into 19 female 90 kg pigs. Blood velocity was measured during open chest conditions in the cross sectional area downstream of the valves with 10 MHz ultrasonic probes connected to a modified Alfred® Pulsed Doppler equipment. As a measure of turbulence, Reynolds normal stress (RNS) was calculated at three different cardiac output ranges (3–4, 4.5–5.5, 6–7 L/min). Results: Data from 12 animals were obtained. RNS correlated with increasing cardiac outputs. The highest instantaneous RNS observed in these experiments was 47 N/m2, and the mean RNS taken spatially over the cross sectional area of the aorta during systole was between 3 N/m2 and 15 N/m2. In none of the cardiac output ranges RNS values exceeded the lower critical limit for erythrocyte or thrombocyte damage for any of the valve designs. Conclusions: Reynolds normal stress values were below 100 N/m2 for all three valve designs and the difference in design was not reflected in generation of turbulence. Hence, it is unlikely that any of the valve designs causes flow induced damage to platelets or erythrocytes. 相似文献
43.
New perspectives for the use of contrast-enhanced liver ultrasound in clinical practice 总被引:1,自引:0,他引:1
L. Bolondi J.M. Correas R. Lencioni H.P. Weskott F. Piscaglia 《Digestive and liver disease》2007,39(2):187-195
The introduction of second-generation microbubble ultrasound contrast agents and the development of contrast specific ultrasound techniques have improved the ability of contrast enhanced ultrasound in detecting and characterising liver lesions, offering new perspectives for its exploitation in clinical hepatology. Indeed, several studies have demonstrated a high diagnostic accuracy in focal lesion characterisation (85-96%) in patients either with or without underlying chronic liver disease. This review article describes the basic principles of contrast enhanced ultrasound, defines the different vascular features of benign and malignant liver lesions, and assesses its clinical impact in different clinical scenarios, according to the guidelines of the European Federation of Societies for Ultrasound in Medicine and Biology, contrast enhanced ultrasound enables the characterisation of focal liver lesions, regardless of the presence or absence of underlying chronic liver disease. Contrast enhanced ultrasound is also useful in staging and follow-up of cancer patients and in monitoring local ablative treatment. Contrast enhanced ultrasound is expected to be considerably increased and replace many computed tomography and magnetic resonance imaging examinations in near future, according to the European Federation of Societies for Ultrasound in Medicine and Biology guidelines. Therefore, it is necessary to take measures in order to meet the demand for an increasing number of these procedures. 相似文献
44.
Hilmar H. Bijma Agnes van der Heide Hajo I. J. Wildschut 《European Clinics in Obstetrics and Gynaecology》2007,3(2):89-95
During the last few decades, the use of ultrasonography for the detection of fetal abnormalities has become widespread in
many industrialised countries. This resulted in a shift in timing of the diagnosis of congenital abnormalities in infants
from the neonatal period to the prenatal period. This has major implications for both clinicians and the couples involved.
In case of ultrasound diagnosis of fetal anomaly, there are several options for the obstetric management, ranging from standard
care to non-aggressive care and termination of pregnancy. This essay explores the context of both clinical and parental decision
making after ultrasound diagnosis of fetal abnormality, with emphasis on the Dutch situation. While normal findings at ultrasound
examination have strong beneficial psychological effects on the pregnant woman and her partner, the couple is often ill prepared
for bad news about the health of their unborn child in the case of abnormal findings. This is, in particular, true in settings
where ultrasonography for the detection of fetal abnormalities is offered as an integral part of antenatal care without appropriate
counselling. An important question is to what extent the couple should be supported in decision making when a fetal abnormality
is diagnosed. In this context, the parental perception of having a choice varies markedly. When parents consider end-of-life
decisions, they experience both ambivalent and emotional feelings. On the one hand, they are committed to their pregnancy,
while on the other hand, they want to protect their child, themselves and the family from the burden of severe disability.
These complex parental reactions have implications for the counselling strategy.
相似文献
Hajo I. J. WildschutEmail: |
45.
Y Miyamoto M Nakatani M Ida T Ishikawa N Okazawa M Ariizumi F Tsujimoto K Mizunuma Y Fukuda S Tada 《Journal of clinical ultrasound : JCU》1989,17(5):309-318
Ultrasonography was performed in 45 cases of gastric cancer. Specimens from all 45 cases of gastric cancer were subjects to ultrasonographic study by the water immersion method for comparison with histology. In 32 of these 45 cases in vivo ultrasonographic evaluation was performed prospectively. The overall accuracy rates for the diagnosis of the depth of cancerous invasion were almost 80% in both in vitro and in vivo studies. In vivo ultrasonographic findings agreed well with those from the specimen studies. Ultrasonography was considered to be useful in the diagnosis of gastric malignancies. 相似文献
46.
L. Rosenthall 《Calcified tissue international》1997,61(2):139-141
This study was designed to determine the changes in precision of the ultrasound parameters speed of sound (SOS), broadband
ultrasound attenuation (BUA), and stiffness index (SI) as a function of bone quality. The instrument used in this investigation
was the LUNAR Achilles. Of the 608 female patients who had paired measurements with repositioning, 200 had t scores ≥−1 and 408 had t scores ≤−2.5, thus rendering a normal and a grossly abnormal group for comparison of precision results. It was found that
the median precision error (CV%) for BUA was 1.99% for normal bone and 1.44% for abnormal bone (P= 0.02). No significant difference was obtained between median precision errors in normal and abnormal bone for the parameters
SOS and SI, which were 0.23% and 0.19%, and 2.15% and 2.02%, respectively. In the interquartile range, the mean precision
errors for SOS and BUA were significantly different in normal and abnormal bone: SOS was 0.25% and 0.21%, respectively, and
BUA was 2.31% and 1.85%, respectively. No significant change was registered for SI. Precision error appears to decrease slightly
at lower values for calcaneal variables.
Received: 21 August 1996 / Accepted: 5 March 1997 相似文献
47.
T. J. Vogl S. Steiner B. Schnell A. Gerbes C. McMahon C. Wilimzig J. Lissner 《European radiology》1992,2(4):310-316
Twenty-nine patients with diffuse liver disease were examined by ultrasound, CT and MRI. MRI was performed using T1- and T2-weighted spin-echo sequences as well as fast gradient-echo-sequences. The paramagnetic contrast agent Gd-DTPA was applied intravenously (0.1 mmol/kg). in patients with hepatitis, MRI could be used in guiding liver biopsies as inflammatory changes were clearly delineated. CT and ultrasound were superior to MRI in the detection of focal or diffuse fatty degeneration. On the other hand MRI was more helpful in differentiating fatty changes and neoplasm. In liver cirrhosis, fibrotic changes were most clearly demonstrated by MRI. In patients suffering from hemochromatosis MRI offers advantages over CT and ultrasound in the diagnosis and follow up due to the paramagnetic properties of iron, resulting in a reduction in signal intensity. In patients with Wilson's disease a characteristic pattern of parenchymal changes was seen. Administration of Gd- DTPA contributes additional information about perfusion conditions in the liver parenchyma, however this information was not of diagnostic relevance in the cases we studied.
Correspondence to: T.J. Vogl 相似文献
48.
Nephrocalcinosis (NC) detected by ultrasound is a recognized abnormality for some patients with X-linked hypophosphatemia (XLH) who received vitamin D2 and inorganic phosphate therapy, but is commonly observed in XLH patients treated with 1,25-dihydroxyvitamin D3 and inorganic phosphate supplementation. Nevertheless, long-term follow-up of kidney function in XLH patients with NC detected ultrasonographically has not been reported. We investigated two women with XLH, ages 31 (patient 1) and 39 (patient 2) years, each of whom had suffered at least one documented episode of vitamin D2-induced hypercalcemia and renal azotemia during childhood. Patient 2 had also been treated with inorganic phosphate. No medications for XLH had been taken during adulthood. Renal ultrasonography at our institution demonstrated marked bilateral medullary NC in both women. No other explanation was found for their NC that apparently occurred several decades earlier from medical therapy for XLH. Detailed studies (including creatinine clearance, β2-microglobulin excretion, and fasting urinary osmolality and acidification) revealed no impairment of kidney function in either patient. Our findings indicate that subradiographic medullary NC acquired during medical therapy for XLH may persist for decades, but with no adverse renal sequelae. Definitive (long-term) assessment of kidney function in the XLH population with NC, however, will be necessary to fully understand the risk of current medical treatment for this most common heritable form of rickets. 相似文献
49.
目的:探讨彩超检测高血脂患者颈动脉内膜-中膜厚度及斑块形成的意义,方法:medison-8000Ex高频超声对120例高血脂患者及120例血脂正常者两组,观察其动脉的内膜-中膜厚度及斑块形成情况。结果:血脂升高组,颈总动脉最大内膜-中膜厚度及粥样斑块发生率明显增高。结论:彩超可清晰显示颈动脉内膜-中膜情况,对高血脂引起的动脉粥样硬化检出预报和疗效观察有重要临床意义。 相似文献
50.
Pornpatr Likittanasombut MD Patrick Reynolds MD Dana Meads RVT Charles Tegeler MD 《Journal of neuroimaging》2006,16(1):34-38
BACKGROUND: Common carotid artery (CCA) volume flow rate (VFR) is clinically useful for study of cerebrovascular disease. Color Velocity Imaging Quantification (CVI-Q; Philips Ultrasound International, Irvine, CA), previously reported as accurate and reliable, tracks the flow lumen over the cardiac cycle, as well as mean spatial velocity, which is multiplied by vessel area to obtain VFR. VFR can also be obtained by Doppler sampling for mean velocity, and vessel area based on static B-mode lumen diameter. We compared CCA VFR by CVI-Q and Doppler method (DM), since knowledge of how they compare is crucial when both are used clinically. METHOD: We prospectively studied patients having clinical carotid duplex exams and healthy controls. All had CCA VFR measured by both methods in the same exam session. RESULTS: Thirty-four studies were reviewed. CCA VFR by CVI-Q in those without ICA stenosis was 337 +/- 96 mL/m, and by DM 359 +/- 130 mL/m; P = .33. There was no difference between methods for 50-75% or 75-95% ICA stenosis. In 7 patients with ICA occlusion, and 3 with 95-99% stenosis, VFR was higher by DM than by CVI-Q (Occlusion: 125 vs 58 mL/m, P = .007; 95-99%: 152 vs 63 mL/m, P = .038). There was no statistically significant difference between methods for measurement of the ratio of VFR between right and left CCA. CONCLUSION: In patients with 0-95% ICA stenosis, VFR by CVI-Q and DM showed no difference. For 95-100% ICA stenosis the methods differ; with higher VFR by DM. Side-to-side VFR ratios remain constant, irrespective of VFR method, and can still provide clinically useful information. 相似文献