Assessment of the relationship between the hepatic contrast enhancement effect in the hepatobiliary phase and hepatic signal changes in free-breathing continuous multiphasic dynamic EOB-MRI

2021 ◽  
Vol 144 ◽  
pp. 109959
Author(s):  
Masaya Tanabe ◽  
Masahiro Tanabe ◽  
Matakazu Furukawa ◽  
Etsushi Iida ◽  
Munemasa Okada ◽  
...  
Keyword(s):  
Contrast Enhancement ◽  
Free Breathing ◽  
Enhancement Effect ◽  
Hepatobiliary Phase ◽  
Signal Changes ◽  
The Relationship

Magnetic Resonance Imaging of Uncommon Hepatic Mesenchymal Tumours: Haemangioendothelioma and Angiosarcoma

2019 ◽  
Vol 15 (4) ◽  
pp. 362-368
Author(s):  
Andrzej Cieszanowski ◽  
Agnieszka Anysz-Grodzicka ◽  
Joanna Podgorska ◽  
Beata Jagielska ◽  
Jakub Pałucki
Keyword(s):  
Contrast Enhancement ◽  
Correct Diagnosis ◽  
Malignant Potential ◽  
Hepatobiliary Phase ◽  
Imaging Features ◽  
Liver Tumours ◽  
Aged Woman ◽  
High Apparent Diffusion Coefficient ◽  
Adc Values ◽  
Mesenchymal Tumours

<P>Background: Primary Hepatic Epithelioid Haemangioendothelioma (HEHE) and Primary Hepatic Angiosarcoma (PHA) are rare mesenchymal tumours with different malignant potential. Whereas HEHE demonstrates low to intermediate malignant potential, PHA is an aggressive malignancy with poor prognosis. The knowledge of typical imaging features of these lesions may facilitate correct diagnosis; however, the ultimate diagnosis of HEHE and PHA is based on histopathologic examination. </P><P> Discussion: The most typical findings helpful in diagnosing HEHE are: Presence of multiple, confluent nodules located at the liver periphery (in young to middle-aged woman), retraction of the liver capsule, marked hyperintensity on T2-weighted images, “target-sign” appearance, progressive centripetal contrast enhancement, and relatively high Apparent Diffusion Coefficient (ADC) values. More than &#8805;50% of nodules are hyper- or isointense on Hepatobiliary Phase (HBP) images. Conclusion: The imaging features suggestive of PHA are: Occurrence of metastases (lungs, spleen) at the time of diagnosis, presence of a large dominant mass with smaller satellites, heterogeneity and areas of haemorrhage in a dominant mass, progressive contrast enhancement, slightly elevated ADC values as compared to other malignant liver tumours.</P>

Pulse-Width Modulated Amplifier for DC Servo System and Its Matlab Simulation

2015 ◽  
Vol 9 (1) ◽  
pp. 625-631
Author(s):  
Ma Xiaocheng ◽  
Zhang Haotian ◽  
Cheng Yiqing ◽  
Zhu Lina ◽  
Wu Dan
Keyword(s):  
Mathematical Model ◽  
Transfer Function ◽  
Input Signal ◽  
Pulse Width ◽  
Rotation Speed ◽  
Servo Motor ◽  
Matlab Simulation ◽  
Pulse Width Modulated ◽  
Signal Changes ◽  
The Relationship

This paper introduces a mathematical model for Pulse-Width Modulated Amplifier for DC Servo Motor. The relationship between pulse-width modulated (PWM) signal and reference rotation speed is specified, and a general model of motor represented by transfer function is also put forward. When the input signal changes, the rotation speed of the servo motor will change accordingly. By changing zeros and poles, transient performance of this system is discussed in detail, and optimal ranges of the parameters is recommended at the end of discussion.

scholarly journals Contrast enhancement effect of CT scan in an acute stage of hypertensive intracerebral hematoma

Nosotchu ◽  
1983 ◽  
Vol 5 (3) ◽  
pp. 180-185
Author(s):  
Masakazu Kitahara ◽  
Akira Ogawa ◽  
Shinro Komatsu ◽  
Yoshiharu Sakurai ◽  
Jiro Suzuki
Keyword(s):  
Ct Scan ◽  
Contrast Enhancement ◽  
Acute Stage ◽  
Intracerebral Hematoma ◽  
Enhancement Effect

New Boundaries, New Relationships

2020 ◽  
pp. 79-97
Author(s):  
LaTonya J. Trotter
Keyword(s):  
Registered Nurses ◽  
Nurse Practitioner ◽  
Power Relations ◽  
Medical Work ◽  
Nurses And Physicians ◽  
Signal Changes ◽  
The Difference ◽  
The Stability ◽  
The One ◽  
The Relationship

This chapter evaluates how the presence of the nurse practitioner (NP) does not just signal changes in nursing work; it portends changes in medical work. Although real tensions exist between nurses and physicians, broadly speaking, they have worked collegially alongside one another for well over a century. This collegiality has endured despite significant changes in what both physicians and nurses do for patients. Its endurance, however, has been predicated on the one thing that has not changed: the power relations between the two. It is the difference in authority, and not just the difference in work, that undergirds the stability of the relationship between the two professions. The NP threatens to disrupt that stability. When registered nurses (RNs) become NPs, they are not just learning new skills; they are crossing lines of authority that they had previously learned to treat as constitutive of their profession. The chapter then looks at the voices and experiences of the NPs of Forest Grove Elder Services. Their narrated and actual practices negotiated physician authority in very different ways.

scholarly journals Investigation of the Relationship between Compressive Strength and Hydrate Formation Behavior of Low-Temperature Cured Cement upon Addition of a Nitrite-Based Accelerator

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3936 ◽  
Author(s):  
Jihoon Kim ◽  
Daiki Honda ◽  
Heesup Choi ◽  
Yukio Hama
Keyword(s):  
Compressive Strength ◽  
Calcium Nitrate ◽  
Hydrate Formation ◽  
Strength Development ◽  
Early Age ◽  
Enhancement Effect ◽  
Freezing Damage ◽  
Formation Behavior ◽  
Relative Production ◽  
The Relationship

When concrete is used for construction in cold-temperature regions, cold-resistant accelerators based on calcium nitrite (Ca(NO2)2) and calcium nitrate (Ca(NO3)2) are added to prevent early freezing damage. Although cold-resistant accelerators increase the early compressive strength and prevent early freezing damage by promoting cement hydration, the strength enhancement effect owing to the formation of such hydrates has not been evaluated quantitatively thus far. This study covers various types of analysis to understand the relationship between cement hydrate formation behavior and strength development upon the addition of varying amounts of nitrite-based accelerator. We find that the early compressive strength is enhanced by the addition of nitrite-based accelerator via the promotion of the relative production of monosulfate and C-S-H in the early age. However, the development of compressive strength decreases with an increase in the curing age. Furthermore, we find that the promotion of hydration reactions at an early age with the addition of nitrite-based accelerator can affect the formation ratio of each hydrate at a late age. We believe our findings can significantly contribute to developments in concrete application and allied fields.

Dynamic Contrast Perception Assessed by Pattern Masking

Perception ◽  
1996 ◽  
Vol 25 (1_suppl) ◽  
pp. 19-19
Author(s):  
R W Bowen ◽  
H de Ridder
Keyword(s):  
Spatial Frequency ◽  
Contrast Enhancement ◽  
Time Course ◽  
Negative Contrast ◽  
Positive Contrast ◽  
Opposite Polarity ◽  
Enhancement Effect ◽  
Mask Duration ◽  
Pattern Masking ◽  
Contrast Perception

The perceived contrast of a pulsed grating of about 100 ms duration can exceed that of shorter or longer exposures. We investigated this contrast enhancement effect with pattern masking. The pulsed mask patterns were extended cosines (5 deg square, 35 cd m−2 mean luminance, 0.3 contrast) of 50 to 500 ms duration. Mask spatial frequency was 1 or 6 cycles deg−1. The test patterns (of equivalent spatial frequency) were sixth derivative Gaussians, either positive (ON pathway mediation) or negative (OFF pathway mediation) and of 30 ms duration. The test pattern could be centred on a light bar of the cosine (positive contrast) or a dark bar (negative contrast). Test and mask had simultaneous onset. For a 1 cycle deg−1 test and mask of the same polarity, the test threshold/mask duration function is nonmonotonic (peak at 83 – 100 ms). The function was similar for either positive or negative stimuli. Thus, we measured an analogue to the contrast enhancement effect, and found enhancement for negative as well as positive contrast components. For same-polarity 6 cycles deg−1 test and mask, threshold increased monotonically to 500 ms (no enhancement). For both 1 and 6 cycles deg−1 stimuli of opposite polarity, the threshold/mask duration function is sharply elevated and constant for masks of 83 ms or more. The same-polarity masking functions imply activation of either transient (1 cycle deg−1 stimuli) or sustained (6 cycles deg−1 stimuli) ON or OFF pathways. The opposite-polarity functions suggest that the time course of ON — OFF pathway interaction is similar for sustained and transient pathways.

177 The Relationship Between MRI Signal Intensity Changes, Clinical Presentation, and Surgical Outcome in Degenerative Cervical Myelopathy: Analysis of a Global Cohort

Neurosurgery ◽  
2017 ◽  
Vol 64 (CN_suppl_1) ◽  
pp. 246-246
Author(s):  
Aria Nouri ◽  
Allan R Martin ◽  
So Kato ◽  
Hamed Reihani-Kermani ◽  
Lauren Riehm ◽  
...  
Keyword(s):  
Cervical Myelopathy ◽  
Surgical Outcome ◽  
Neurological Recovery ◽  
Recovery Ratio ◽  
Baseline Severity ◽  
Signal Change ◽  
Signal Changes ◽  
T2 Hyperintensity ◽  
Degenerative Cervical Myelopathy ◽  
The Relationship

Abstract INTRODUCTION Several reports have investigated the relationship between MRI signal changes and the extent of spinal cord dysfunction and potential for postoperative neurological recovery in patients with Degenerative Cervical Myelopathy (DCM). However, there remains ambiguity if these signal changes relate with baseline severity, and predict neurological recovery after surgical treatment. The present study aims to address this knowledge gap by investigating a large global cohort of DCM patients. METHODS 419 MRIs from two prospective multicenter studies were examined. Images were assessed for the presence, levels, and location of cord signal changes and compared with clinical data (signs/symptoms, mJOA, Nurick). Inter-rater reliability for signal changes was calculated. Signal changes were also evaluated for prediction of 2-year post-operative outcome using 2 approaches: (1) Hirabayashi recovery ratio, (2) a dichotomized mJOA score of <16 and = 16 at 2-years representing a suboptimal and optimal neurological outcome, respectively. RESULTS >MRIs were categorized by signal change: no signal change (28.9%), T2 hyperintensity-only (T2-only, 51.8%), and T2-hyperintensity and T1-hypointensity (T1+T2, 19.3%). T2-hyperintensity was present at multiple levels in 27% of patients overall. There was moderate/substantial agreement (Kappa: 0.60) for T2-hyperintensity, and fair agreement for T1-hypointensity (Kappa: 0.31) identification among 3 raters. Baseline severity increased from no signal change to T2-only to T2+T1 (P < 0.0001), and there was an incremental increase in the frequency of signs/symptoms. The presence of T1-hypointensity correlated with reduced recovery ratio (P = 0.03) and likelihood of an optimal surgical outcome (P = 0.005). Greater number of T2-hyperintensity levels was also associated with worse baseline severity (P < 0.0001) and recovery ratio (P = 0.001). CONCLUSION This is the largest study of DCM patients to show an increasing stepwise impairment from no signal change to T2-hypertensity to T1-hypointensity. While T2-hyperintensity alone does not predict outcomes, T1-hypointensity indicates more permanent injury, portending decreased functional recovery. Multilevel T2-hyperintensity suggests additional tissue injury, correlating with worse impairment and recovery potential.

A phonetically versatile contrast: Pulmonic and glottalic voicelessness in Scottish English obstruents and voice quality

2013 ◽  
Vol 43 (3) ◽  
pp. 249-271 ◽  
Author(s):  
Olga B. Gordeeva ◽  
James M. Scobbie
Keyword(s):  
Contrast Enhancement ◽  
Voice Quality ◽  
British English ◽  
Acoustic Data ◽  
Enhancement Mechanism ◽  
The Relationship

This paper presents impressionistic, electroglottographic and acoustic data exploring the distribution of glottalic and pulmonic airstream in word-final Scottish English obstruents. We explore the relationship between these airstream mechanisms and aspirated or glottalised phonatory settings of individual speakers near this obstruent locus. We address the hypothesis that the tendency for pre-stop glottalisation found in some British English varieties can explain the occurrence of glottalically-released stops. This hypothesis suggests that ejectives would appear as an occasional artefact of mistimed glottalisation. We also investigate whether a glottalic airstream acts as a potential contrast enhancement mechanism, through association with /−voice/ as opposed to /+voice/ stops. We show that glottalisation and aspiration can readily co-occur in the same speaker, and that local phonatory setting (with glottalised or aspirated articulation) can be consistently used as a secondary correlate of obstruent /−voice/, in the context of stops and fricatives respectively. The results show that although glottalisation as a secondary correlate of /−voice/ stops often co-occurs with an ejective release, they are not necessarily bound together. These results argue against a simple epiphenomenal explanation for the appearance of ejective stops in English, while also showing that they are not (yet) a systematic phonological enhancement in this variety.

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