scholarly journals The Relationship Between Koos Classification and ADC-Post-Contrast Signal Intensity Values of Vestibular Schwannomas

2021 ◽  
Vol 6 (3) ◽  
pp. 144-147
Author(s):  
Umut Percem ORHAN SOYLEMEZ ◽  
Başak ATALAY ◽  
Nesrin GÜNDÜZ
Keyword(s):  
Signal Intensity ◽  
Vestibular Schwannomas ◽  
Post Contrast ◽  
The Relationship

Decreased vestibular signal intensity on 3D-FIESTA in vestibular schwannomas differentiating from meningiomas

2012 ◽  
Vol 55 (3) ◽  
pp. 261-270 ◽  
Author(s):  
Kazuhiro Ishikawa ◽  
Jun Haneda ◽  
Kouichirou Okamoto
Keyword(s):  
Signal Intensity ◽  
Vestibular Schwannomas

Imaging of rare appendicular non-acral soft-tissue chondromas in adults with histopathologic correlation

2017 ◽  
Vol 59 (6) ◽  
pp. 700-708
Author(s):  
Mohamed Ragab Nouh ◽  
Hanan Abd El-Aziz Amr ◽  
Rola H Ali
Keyword(s):  
Soft Tissue ◽  
Signal Intensity ◽  
Tissue Reaction ◽  
High Signal ◽  
Diagnostic Challenge ◽  
Post Contrast ◽  
Intensity Matrix ◽  
Tissue Edema ◽  
Magnetic Resonance Imaging Mri

Background Soft-tissue chondroma (STC) is a rare benign soft tissue tumor that arises primarily in acral extra-skeletal locations. Occasionally, STCs may arise in more proximal non-acral locations, accompanied by non-classic features that label them as indeterminate lesions and pose diagnostic challenge for both radiologists and pathologists alike. Purpose To explicate the potential of diagnostic imaging in the identification and characterization of appendicular non-acral STCs with emphasis on their morphologic magnetic resonance imaging (MRI) enhancement. Material and Methods Our clinical database records were searched for patients with histologically proven primary soft-tissue chondroid lesions over a five-year period. Two musculoskeletal (MSK) trained radiologists evaluated the imaging studies and an MSK pathologist revised the pathological findings. Results The study included six cases of appendicular non-acral STCs (mean age = 40.5 years). The mean size of the tumors was 5.6 cm, with four localized to the knee region, one in the thigh, and one in the sternoclavicular region. All cases showed high signal intensity matrix with low-signal intensity septa on T2-weighted MRI and post-contrast marginal/septal enhancement. The lesions were lobulated and lacked host tissue reaction except for one showing subjacent mild soft-tissue edema. Histologically, the cases lacked overt features of malignancy although one was originally misdiagnosed as chondrosarcoma. Conclusion Non-acral STCs are benign cartilaginous tumors that may pose a diagnostic challenge, both radiologically and pathologically. Collaborative imaging and pathologic workup is needed for better characterization of non-aggression of these lesions, and to avoid diagnostic pitfalls and unnecessary radical resections.

Quantitative analysis of unruptured intracranial aneurysm wall thickness and enhancement using 7T high resolution, black blood magnetic resonance imaging

2021 ◽  
pp. neurintsurg-2021-017688
Author(s):  
Xinke Liu ◽  
Junqiang Feng ◽  
Zhixin Li ◽  
Zihao Zhang ◽  
Qiang Zhang ◽  
...  
Keyword(s):  
Intracranial Aneurysm ◽  
Wall Thickness ◽  
Signal Intensity ◽  
Spin Echo ◽  
Fast Spin Echo ◽  
Black Blood ◽  
Post Contrast ◽  
Isotropic Resolution ◽  
Aneurysm Size ◽  
Aneurysm Wall

BackgroundThis study was performed to quantify intracranial aneurysm wall thickness (AWT) and enhancement using 7T MRI, and their relationship with aneurysm size and type.Methods27 patients with 29 intracranial aneurysms were included. Three-dimensional T1 weighted pre‐ and post-contrast fast spin echo with 0.4 mm isotropic resolution was used. AWT was defined as the full width at half maximum on profiles of signal intensity across the aneurysm wall on pre-contrast images. Enhancement ratio (ER) was defined as the signal intensity of the aneurysm wall over that of the brain parenchyma. The relationships between AWT, ER, and aneurysm size and type were investigated.Results7T MRI revealed large variations in AWT (range 0.11–1.24 mm). Large aneurysms (>7 mm) had thicker walls than small aneurysms (≤7 mm) (0.49±0.05 vs 0.41±0.05 mm, p<0.001). AWT was similar between saccular and fusiform aneurysms (p=0.546). Within each aneurysm, a thicker aneurysm wall was associated with increased enhancement in 28 of 29 aneurysms (average r=0.65, p<0.05). Thicker walls were observed in enhanced segments (ER >1) than in non-enhanced segments (0.53±0.09 vs 0.38±0.07 mm, p<0.001).ConclusionImproved image quality at 7T allowed quantification of intracranial AWT and enhancement. A thicker aneurysm wall was observed in larger aneurysms and was associated with stronger enhancement.

Abstract 14101: A Correction Score for Comparison of Aortic Calcification in Post-contrast and Non-contrast Measurements From Computed Tomography Scans

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Steven R Horbal ◽  
Edward Brown ◽  
Brian A Derstine ◽  
Peng Zhang ◽  
Andrea H Rossman ◽  
...  
Keyword(s):  
Pearson Correlation ◽  
Aortic Calcification ◽  
University Of Michigan ◽  
Variance Inflation Factor ◽  
Post Contrast ◽  
Abdominal Aortic ◽  
Pixel Value ◽  
Inflation Factor ◽  
The University ◽  
The Relationship

Introduction: Aortic calcification can be utilized to assess cardiovascular risk. While contrast is useful for vascular enhancement in diagnostic imaging, enhancement creates heterogeneity between post and non-contrast scans and limits their direct comparability. Hypothesis: We hypothesized that post and non-contrast aortic calcification measures will correlate, and a correction score can be developed for statistical comparability. Methods: Retrospective CT-scans were obtained from the University of Michigan. Participants (N=330) received abdominal scans with and without contrast enhancement within 120 calendar days. Analytic Morphomics was used to obtain vertebral-indexed measurements of aortic calcium area, and aortic wall obfuscation percentage. Calcification was specifically identified as regions with a given morphology and pixel value five standard deviations above the defined central lumen zone. Pearson correlation and multiple linear regression were used to explain the relationship between aortic measurements with and without contrast. Regressions include calcification percent (Model 1), and area (Model 2). Independent variables were non-contrast measurements and dependent variables were contrast measurements, age, and sex. Results: Correlations of calcification percent ranged from 0.86 at T11 and 0.94 and L2. Correlations of calcification area ranged from 0.66 at T12 to 0.84 at L3. In Model 1, for every percent increase in post-contrast calcification, non-contrast calcification percent increased by 11% (β=1.11, p <0.001, R2=0.85). In Model 2, for every mm2 increase in post-contrast calcification area, non-contrast calcification area increased by 0.45 mm2 (β=1.45, p <0.001, R2=0.69). Variance inflation factor for Model 1 was 1.08 and 1.07 for Model 2. Conclusion: In conclusion, this research proposes a correction score for comparisons of abdominal aortic calcification measurements in post-contrast and non-contrast scans.

Acoustic Emission During Athermal Martensitic Transformation in Steels

1990 ◽  
Vol 112 (1) ◽  
pp. 84-91 ◽  
Author(s):  
Xiangying Liu ◽  
Elijah Kannatey-Asibu
Keyword(s):  
Free Energy ◽  
Acoustic Emission ◽  
Martensitic Transformation ◽  
Signal Intensity ◽  
Temperature Derivative ◽  
Process Characteristics ◽  
Ae Signal ◽  
The Relationship ◽  
Ae Signals ◽  
Start Temperature

A relationship developed earlier between acoustic emission signals and the process of athermal martensitic transformation based on the free energy associated with the process is extended and verified experimentally. The relationship is found to model the process characteristics very well. The intensity of AE signal generated during transformation was found to be proportional to the temperature derivative of the fraction of martensite, the cooling rate, and volume of specimen. The AE signal was also found to be related to the carbon content of the steel. During transformation, the signal intensity was found to increase to a peak, and then tail off near the end of the transformation. Values of the martensite start temperature obtained from plots of the total RMS squared AE signals were also found to correlate well with values from the literature.

scholarly journals Signal changes of the alar ligament in a healthy population: a dispositional or degenerative consequence?

2015 ◽  
Vol 23 (5) ◽  
pp. 544-550 ◽  
Author(s):  
Holger Wenz ◽  
Hans Ulrich Kerl ◽  
Mate Elod Maros ◽  
Ralf Wenz ◽  
Kira Kalvin ◽  
...  
Keyword(s):  
Signal Intensity ◽  
Patient Characteristics ◽  
Craniocervical Junction ◽  
Fat Suppression ◽  
Healthy Population ◽  
Operating Characteristics ◽  
Age Related ◽  
3.0 T ◽  
The Relationship ◽  
Signal Intensities

OBJECT The alar ligaments (ALs) are vital for stabilizing the craniocervical junction. In terms of morphology, their appearance varies and is visible on MRI. Dark signal of the AL on proton-density (PD)-weighted images is generally considered the norm, but the etiology of frequently observed signal hyperintensities is poorly understood. Using spectral fat suppression, signal hyperintensities can be differentiated into fat- and nonfat-related hyperintensities (NFH). Although signal hyperintensities have no evident association with whiplash-associated disorder, age-related degeneration has often been theorized. Therefore, this study investigates the signal intensities of the ALs on 3.0-T MRI with special reference to age. Expanding thereon, the authors investigated the relationship between signal hyperintensities and patient characteristics, such as height, weight, and sex. METHODS Sixty-six healthy volunteers were scanned using 3.0-T PD-weighted MRI, including spectral fat suppression of the craniocervical junction. The study population was separated into 2 groups (old vs young) using 2 approaches: dichotomization at the median age (40.0 years) and the calculated threshold (28.5 years) using receiver operating characteristics (ROC). The AL was independently characterized with respect to continuity, course, shape, signal intensity, and graduation of homogeneity by 2 experienced neuroradiologists. Signal intensity was differentiated into fat-related hyperintensity and NFH. Univariate and multivariate logistic regression models were employed to investigate the relationship between patient characteristics and signal intensities. RESULTS Two different AL patterns were observed: inhomogeneous (33.3%) and homogeneous (66.7%). The latter pattern was mostly surrounded by a small dark rim (56.8%). Fat could be identified in 15.9% of all ALs (21 of 132 patients), and NFH was identified in 17.4% of all ALs (23 of 132 patients). Here, 28.5 years was the preferred threshold, demonstrating a relatively high sensitivity for dichotomizing the population based on the ROC of NFH. The most relevant factor for having NFH was being older than the calculated threshold (odds ratio [OR] 3.420, p = 0.051). Fat-related hyperintensities occurred significantly more frequently in men than women (OR 0.110 and p = 0.007 for women; OR 9.075 and p = 0.007 for men). Height was the second most significant factor: for every 1-cm increase, the odds of having fat lesions increased by approximately 10% (OR 1.102; p = 0.017). CONCLUSIONS This study shows that AL signal hyperintensities are substantially influenced by age, sex, and height in healthy individuals. Regarding fat-related hyperintensities, the most relevant factors proved to be sex and height. The odds of detecting NFH increased almost significantly after a relatively young age (> 28.5 years) and were remarkably more frequent in individuals older than 28.5 years. The authors caution presumptions equating signal alterations with age-related deterioration. Instead, they suggest that dispositional factors such as sex and height are more relevant in the AL constitution. Signal alterations in ALs naturally occur in healthy symptom-free individuals, underscoring the importance of cautiously interpreting such lesions on posttraumatic MRI scans.

Contrast magnetic resonance imaging for measurement of cartilage glycosaminoglycan content in dogs: A pilot study

2013 ◽  
Vol 26 (02) ◽  
pp. 100-104 ◽  
Author(s):  
M. C. Stewart ◽  
L. Ciobanu ◽  
P. D. Constable ◽  
J. F. Naughton
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Coefficient Of Variation ◽  
Signal Intensity ◽  
Linear Regression Analysis ◽  
Resonance Imaging ◽  
Post Contrast ◽  
Enhanced Mri ◽  
Over Time

SummaryObjective: To assess the ability of a contrast-enhanced magnetic resonance imaging (MRI) technique to quantitatively determine glycosaminoglycan content in canine articular cartilage.Methods: Fifty-four full-thickness cartilage discs were collected from the femorotibial and scapulohumeral joints of three adult dogs immediately following euthanasia. One set of discs from each dog was analysed for glycosaminoglycan content using a colourimetric laboratory assay. The remaining position-matched set of discs from contralateral limbs underwent pre- and post-contrast gadolinium-enhanced MRI, using repeated saturation recovery pulse sequences which were used to generate calculated T1 maps of the cartilage discs. Linear regression analysis was then performed relating delayed gadolinium-enhanced MRI T1 calculated signal intensity to the cartilage glycosaminoglycan content normalized to DNA content. Repeatability of triplicate measurements was estimated by calculating the coefficient of variation.Results: Mean coefficient of variation estimates for the gadolinium-enhanced MRI T1 signal intensity values for nine sampling sites from three dogs ranged from 5.9% to 7.5%. Gadolinium-enhanced MRI T1 signal intensity was significantly correlated (p <0.05) with normalized glycosaminoglycan content in two dogs (r = 0.79, p = 0.011; r = 0.78, p = 0.048), but not in the third dog (r = 0.53, p = 0.071).Clinical significance: Gadolinium-enhanced MRI assessment of cartilage may be predictive of glycosaminoglycan content and therefore offer an in vivo assessment of changes in cartilage characteristics over time. Additional studies appear indicated to determine the reliability and clinical applicability of gadolinium-enhanced MRI in detecting changes in cartilage over time.

scholarly journals Correlative Magnetic Resonance Imaging and Histopathology in Small Ruminant Listeria Rhombencephalitis

2020 ◽  
Vol 11 ◽  
Author(s):  
Christina Precht ◽  
Peter Vermathen ◽  
Diana Henke ◽  
Anne Staudacher ◽  
Josiane Lauper ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Contrast Enhancement ◽  
Signal Intensity ◽  
Small Ruminants ◽  
Large Animal ◽  
Resonance Imaging ◽  
Post Contrast ◽  
Mri Features ◽  
Inflammatory Infiltrates

Background: Listeria rhombencephalitis, infection of the brainstem with Listeria monocytogenes, occurs mainly in humans and farmed ruminants and is associated with high fatality rates. Small ruminants (goats and sheep) are a large animal model due to neuropathological similarities. The purpose of this study was to define magnetic resonance imaging (MRI) features of listeria rhombencephalitis in naturally infected small ruminants and correlate them with histopathology. Secondly, the purpose of this study was to compare the results with MRI findings reported in humans.Methods: Twenty small ruminants (13 sheep and 7 goats) with listeria rhombencephalitis were prospectively enrolled and underwent in vivo MRI of the brain, including T2-weighted, fluid attenuation inversion recovery, and T1-weighted sequences pre- and post-contrast administration and postmortem histopathology. In MRI, lesions were characterized by location, extent, border definition, signal intensity, and contrast enhancement. In histopathology, the location, cell type, severity, and chronicity of inflammatory infiltrates and signs of vascular damage were recorded. In addition, histopathologic slides were matched to MRIs, and histopathologic and MRI features were compared.Results: Asymmetric T2-hyperintense lesions in the brainstem were observed in all animals and corresponded to the location and pattern of inflammatory infiltrates in histopathology. Contrast enhancement in the brainstem was observed in 10 animals and was associated with vessel wall damage and perivascular fibrin accumulation in 8 of 10 animals. MRI underestimated the extension into rostral brain parts and the involvement of trigeminal ganglia and meninges.Conclusion: Asymmetric T2-hyperintense lesions in the brainstem with or without contrast enhancement can be established as criteria for the diagnosis of listeria rhombencephalitis in small ruminants. Brainstem lesions were similar to human listeria rhombencephalitis in terms of signal intensity and location. Different from humans, contrast enhancement was a rare finding, and abscessation was not observed.

Study of High Sensitivity Sensor Based on the Principle of Photoionization

2012 ◽  
Vol 503 ◽  
pp. 188-193 ◽  
Author(s):  
Kun Wang Niu ◽  
Ting Liang ◽  
Fang Yang ◽  
Qing Meng ◽  
Kai Wang ◽  
...  
Keyword(s):  
Bias Voltage ◽  
Signal Intensity ◽  
Ionization Chamber ◽  
Detection Efficiency ◽  
High Sensitivity ◽  
Signal Strength ◽  
Detection Sensitivity ◽  
Weak Signal Detection ◽  
The Relationship

The quality of designing structure and properties of sensor photoionization room，directly determines its weak signal detection sensitivity detection and effecting ionization chamber detection efficiency .The paper experiments on four factors of affect the sensitivity of sensor. The results show that: the signal intensity proportional to the area of the ionization chamber; signal intensity goes up with the increase of bias voltage, and with bias voltage into a square the relationship; signal strength was first increased and then decreased with the growth of the distance between electrodes; signal strength was first increased and then decreased. With the growth of light-driven power.

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