| 1. |
- Danielsson, R, et al.
(författare)
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Sensitivity and specificity of planar scintimammography with 99mTc-sestamibi
- 1999
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Ingår i: Acta radiologica (Stockholm, Sweden : 1987). - : SAGE Publications. - 0284-1851 .- 1600-0455. ; 40:4, s. 394-399
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The aim of our prospective study was to determine the diagnostic accuracy of planar breast imaging with 99mTc-MIBI in detecting malignant disease. Material and Methods: Ninety-six consecutive patients with 121 clinically-and/or mammographically-detected breast lesions underwent preoperative planar scintimammography. Ten minutes after injection of 700 MBq99mTc-MIBI, two lateral prone and one anterior supine projections with an acquisition time of 8 minutes each were obtained. Interpretation of scintimammographic results was made blindly and any focal accumulation of MIBI in the breasts was the criterion for an abnormal scintigram. All lesions were operated on and histologically verified. Results: Histologically, 86 malignant and 35 benign lesions were found in 121 breast lesions. A sensitivity of 83.7% and a specificity of 74.2% for malignancy was achieved at planar scintimammography. Conclusion: Scintimammography with 99mTc-MIBI is an imaging modality of modest usefulness in the investigation of breast lesions. The method has a low sensitivity in lesions smaller than 10 mm in diameter, which decreases the clinical use of the method.
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| 2. |
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| 3. |
- Löfdahl, Lennart, 1948, et al.
(författare)
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MEMS Applications in Turbulence and Flow Control
- 1999
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Ingår i: Progress in Aerospace Sciences. ; 35, s. 101-203
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Tidskriftsartikel (refereegranskat)abstract
- Manufacturing processes that can create extremely small machines have been developed in recent years. Microelectromechanical systems (MEMS) refer to devices that have characteristic length of less than 1 mm but more than 1 μm, that combine electrical and mechanical components and that are fabricated using integrated circuit batch-processing techniques. Electrostatic, magnetic, pneumatic and thermal actuators, motors, valves, gears and tweezers of less than 100 μm size have been fabricated. These have been used as sensors for pressure, temperature, mass flow, velocity and sound, as actuators for linear and angular motions, and as simple components for complex systems such as micro-heat-engines and micro-heat-pumps. In this paper, we focus on the microelectromechanical systems for the diagnosis and control of turbulent shear flows. We survey the status and outlook of microsensors and microactuators as used for those particular applications, and compare the minute devices to their larger cousins. Microsensors can resolve all relevant scales even in high-Reynolds-number turbulent flows. Arrays of microsensors and microactuators make it feasible, for the first time, to achieve effective reactive control targeted toward specific small-scale coherent structures in turbulent wall-bounded flows.
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| 4. |
- Löfdahl, Lennart, 1948, et al.
(författare)
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MEMS based Pressure and Shear Stress Sensors for Turbulet Flows
- 1999
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Ingår i: Measurements Science and Technology. ; 10, s. 665-686
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Tidskriftsartikel (refereegranskat)abstract
- From a fluid dynamics perspective, the introduction of microelectromechanical systems (MEMS) has considerably broadened the spectrum of workable experiments. A typical MEMS sensor is at least one order of magnitude smaller than traditional sensors used to measure instantaneous flow quantities such as pressure and velocity. The microsensors can resolve all relevant scales even in high-Reynolds-number turbulent flows, and arrays of microsensors make it feasible, for the first time, to achieve complete information on the effective small-scale coherent structures in turbulent wall-bounded flows. In this paper we focus on the use of MEMS for the diagnosis of turbulent shear flows and survey the status and outlook of microsensors as used for measurements of fluctuating wall pressure and wall shear stress, two quantities which we deem particularly difficult to measure with conventional probes. For both wall pressure and wall shear stress sensors, we give general background, design criteria and calibration procedure. Examples of measurements conducted with MEMS-based sensors are provided and the minute devices are compared to their larger cousins.
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| 5. |
- Movin, T, et al.
(författare)
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Intratendinous alterations as imaged by ultrasound and contrast medium-enhanced magnetic resonance in chronic achillodynia
- 1998
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Ingår i: Foot & ankle international. - : SAGE Publications. - 1071-1007 .- 1944-7876. ; 19:5, s. 311-317
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: We performed a comparative study of ultrasonography and gadolinium imaging contrast-enhanced T1-weighted magnetic resonance to evaluate tendon pathology in chronic Achilles tendon disorder. Another main issue was to evaluate the structural basis as defined by histopathology from hypoechoic compared with normoechic areas within the same tendon. Materials and Methods: Twenty patients (16 male, 4 females, median age 40 years) with chronic achillodynia participated in the study. Clinical examination revealed swelling and tenderness localized to the midportion of the Achilles tendon. Contrast medium-enhanced magnetic resonance imaging (CME-MRI) was performed in all patients. Ultrasonography-guided core biopsies were taken from regions with a clear widening of the tendon and a pathologic low-echo signal as well as from normoechoic areas. The specimens were analyzed with a standardized protocol giving a total tendon score (0–24), and a stereologic method for quantification of glycosaminoglycan (GAG)-rich areas. Results: The volume of the intratendinous abnormality was larger in 13 of 20 when imaged by CME-MR ( P < 0.05), whereas the shape and enlargement of the tendon per se were similarly imaged by ultrasound (US) and CME-MR. Tendon pathology as imaged by US was graded as severe from hypoechoic regions and moderate from normoechoic regions. The corresponding quantification of GAGs was 0.36 compared with 0.17, respectively ( P < 0.001). Conclusion: CME-MR imaging revealed greater sensitivity in demonstrating intratendinous pathology than the ultrasound; this was documented by the larger size of the corresponding lesion and the fact that the pathology was occurring in areas that were considered normal by ultrasonography. US hypoechoic areas showed a markedly abnormal tendon structure including an increased amount of GAG-rich areas. However, moderate pathology was also found in the neighboring normoechogenous areas within the same tendon, indicating a more generalized disorder than depicted by echogenic properties.
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