scholarly journals Optimized Breath-Hold Compressed-Sensing 3D MR Cholangiopancreatography at 3T: Image Quality Analysis and Clinical Feasibility Assessment

Diagnostics ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 376
Author(s):  
Ji Soo Song ◽  
Seung Hun Kim ◽  
Bernd Kuehn ◽  
Mun Young Paek
Keyword(s):  
Image Quality ◽  
Compressed Sensing ◽  
Signal To Noise Ratio ◽  
Contrast Ratio ◽  
Magnetic Resonance Cholangiopancreatography ◽  
Quality Analysis ◽  
Acquisition Time ◽  
Breath Hold ◽  
Background Suppression ◽  
Noise Ratio

Magnetic resonance cholangiopancreatography (MRCP) has been widely used in clinical practice, and recently developed compressed-sensing accelerated MRCP (CS-MRCP) has shown great potential in shortening the acquisition time. The purpose of this prospective study was to evaluate the clinical feasibility and image quality of optimized breath-hold CS-MRCP (BH-CS-MRCP) and conventional navigator-triggered MRCP. Data from 124 consecutive patients with suspected pancreaticobiliary diseases were analyzed by two radiologists using a five-point Likert-type scale. Communication between a cyst and the pancreatic duct (PD) was analyzed. Signal-to-noise ratio (SNR) of the common bile duct (CBD), contrast ratio between the CBD and periductal tissue, and contrast-to-noise ratio (CNR) of the CBD and liver were measured. Optimized BH-CS-MRCP showed significantly fewer artifacts with better background suppression and overall image quality. Optimized BH-CS-MRCP demonstrated communication between a cyst and the PD better than conventional MRCP (96.7% vs. 76.7%, p = 0.048). SNR, contrast ratio, and CNR were significantly higher with optimized BH-CS-MRCP (p < 0.001). Optimized BH-CS-MRCP showed comparable or even better image quality than conventional MRCP, with improved visualization of communication between a cyst and the PD.

scholarly journals Comparison of Compressed Sensing and Gradient and Spin-Echo in Breath-Hold 3D MR Cholangiopancreatography: Qualitative and Quantitative Analysis

Diagnostics ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 634
Author(s):  
Weon Jang ◽  
Ji Soo Song ◽  
Sang Heon Kim ◽  
Jae Do Yang
Keyword(s):  
Image Quality ◽  
Compressed Sensing ◽  
Spin Echo ◽  
Contrast Ratio ◽  
Rank Test ◽  
Breath Holding ◽  
Breath Hold ◽  
Background Suppression ◽  
Time Saving ◽  
Noise Ratio

While magnetic resonance cholangiopancreatography (MRCP) is routinely used, compressed sensing MRCP (CS-MRCP) and gradient and spin-echo MRCP (GRASE-MRCP) with breath-holding (BH) may allow sufficient image quality with shorter acquisition times. This study qualitatively and quantitatively compared BH-CS-MRCP and BH-GRASE-MRCP and evaluated their clinical effectiveness. Data from 59 consecutive patients who underwent both BH-CS-MRCP and BH-GRASE-MRCP were qualitatively analyzed using a five-point Likert-type scale. The signal-to-noise ratio (SNR) of the common bile duct (CBD), contrast-to-noise ratio (CNR) of the CBD and liver, and contrast ratio between periductal tissue and the CBD were measured. Paired t-test, Wilcoxon signed-rank test, and McNemar’s test were used for statistical analysis. No significant differences were found in overall image quality or duct visualization of the CBD, right and left 1st level intrahepatic duct (IHD), cystic duct, and proximal pancreatic duct (PD). BH-CS-MRCP demonstrated higher background suppression and better visualization of right (p = 0.004) and left 2nd level IHD (p < 0.001), mid PD (p = 0.003), and distal PD (p = 0.041). Image quality degradation was less with BH-GRASE-MRCP than BH-CS-MRCP (p = 0.025). Of 24 patients with communication between a cyst and the PD, 21 (87.5%) and 15 patients (62.5%) demonstrated such communication on BH-CS-MRCP and BH-GRASE-MRCP, respectively. SNR, contrast ratio, and CNR of BH-CS-MRCP were higher than BH-GRASE-MRCP (p < 0.001). Both BH-CS-MRCP and BH-GRASE-MRCP are useful imaging methods with sufficient image quality. Each method has advantages, such as better visualization of small ducts with BH-CS-MRCP and greater time saving with BH-GRASE-MRCP. These differences allow diverse choices for visualization of the pancreaticobiliary tree in clinical practice.

scholarly journals Accelerated 3D T2-Weighted SPACE Using Compressed Sensing for Paediatric Brain Imaging

2021 ◽  
Author(s):  
Hyun Gi Kim ◽  
Se Won Oh ◽  
Dongyeob Han ◽  
Jee Young Kim ◽  
Gye Yeon Lim
Keyword(s):  
White Matter ◽  
Image Quality ◽  
Compressed Sensing ◽  
Brain Imaging ◽  
Quality Analysis ◽  
Acquisition Time ◽  
Image Quality Analysis ◽  
Space Group ◽  
Quantitative Image ◽  
Noise Ratio

Abstract The purpose of this study was to compare the image quality of the single-slab, 3D T2-weighted turbo-spin-eco sequence with high sampling efficiency (SPACE) with accelerated SPACE using compressed sensing (CS-SPACE) in paediatric brain imaging. A total of 116 brain MRI (53 in SPACE group and 63 in CS-SPACE group) were obtained from children aged 16 years old or younger. Quantitative image quality was evaluated using the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). The sequences were qualitatively evaluated for overall image quality, SNR, general artifact, cerebrospinal fluid (CSF)-related artifact and grey-white matter differentiation. The two sequences were compared for the total and for two age groups (< 24 months vs. ≥ 24 months). CS application in 3D T2-weighted imaging resulted in 8.5% reduction in scanning time. Quantitative image quality analysis showed higher SNR (Median [Interquartile range]; 29 [25] vs. 23 [14], P = .005) and CNR (0.231 [0.121] vs. 0.165 [0.120], P = .027) with CS-SPACE compared to SPACE. Qualitative image quality analysis showed better image quality with CS-SPACE for general artifact (P = .024) and CSF-related artifact (P < .001). CSF-related artifacts reduction was more prominent in the older age group (≥ 24 months). Overall image quality (P = .162), SNR (P = .726), and grey-white matter differentiation (P = .397) were comparable between SPACE and CS-SPACE. In conclusion, compressed sensing applied 3D T2-weighted images showed comparable or superior image quality compared to conventional images with reduced acquisition time for paediatric brain.

scholarly journals Evaluation Comparison Image Quality of Breath Hold (SSTSE) and Respiratory Triggering (TSE) Technique to the Examination of Magnetic Cholangiopancreatography (MRCP)

2017 ◽  
Vol 1 (2) ◽  
pp. 39
Author(s):  
Nikky Anis Suroiyah ◽  
Risalatul Latifah ◽  
Sri Andreani Utomo
Keyword(s):  
Image Quality ◽  
Pancreatic Duct ◽  
Signal To Noise Ratio ◽  
Magnetic Resonance Cholangiopancreatography ◽  
Breath Hold ◽  
Signal To Noise ◽  
Human Bile ◽  
Noise Ratio ◽  
Respiratory Triggering

Background : Magnetic resonance cholangiopancreatography (MRCP) is MRI examination to visualize to visualize a disorder in part biliary or of the human bile. The artefact in the image MRCP is often happened due to the movement of respiratory system. Purpose :  This study to compare the better image quality between Breath Hold (SSTSE) and Repiratory Triggering (TSE)techinques. Methods : This study used observational analytic study with prospective approach. 16 samples were examined with two techniques SSTSE and TSE respectively in order to get 3D MRCP image. The Signal to Noise Ratio (SNR) and Contrast to Noise Ratio (CNR) is measured to evaluate the image quality. Result: The SSTSE technique only has a higher SNR in gallbladder meanwhile the TSE technique has a higher SNR in pancreatic duct. The higher CNR is got using TSE technique. Conclusion :  The TSE showed the higher SNR in pancreatic duct and the higher CNR is got with SSTSE technique. The recommendation technique for evaluating pancreatic duct is respiratory triggering.

scholarly journals Effect of respiratory motion correction and CT-based attenuation correction on dual-gated cardiac PET image quality and quantification

2021 ◽  
Author(s):  
Jussi Schultz ◽  
Reetta Siekkinen ◽  
Mojtaba Jafari Tadi ◽  
Mika Teräs ◽  
Riku Klén ◽  
...  
Keyword(s):  
Image Quality ◽  
Motion Correction ◽  
Respiratory Motion ◽  
Signal To Noise Ratio ◽  
Contrast Ratio ◽  
Signal To Noise ◽  
4D Ct ◽  
Myocardial Wall ◽  
Dual Gating ◽  
Noise Ratio

Abstract Background Dual-gating reduces respiratory and cardiac motion effects but increases noise. With motion correction, motion is minimized and image quality preserved. We applied motion correction to create end-diastolic respiratory motion corrected images from dual-gated images. Methods [18F]-fluorodeoxyglucose ([18F]-FDG) PET images of 13 subjects were reconstructed with 4 methods: non-gated, dual-gated, motion corrected, and motion corrected with 4D-CT (MoCo-4D). Image quality was evaluated using standardized uptake values, contrast ratio, signal-to-noise ratio, coefficient of variation, and contrast-to-noise ratio. Motion minimization was evaluated using myocardial wall thickness. Results MoCo-4D showed improvement for contrast ratio (2.83 vs 2.76), signal-to-noise ratio (27.5 vs 20.3) and contrast-to-noise ratio (14.5 vs 11.1) compared to dual-gating. The uptake difference between MoCo-4D and non-gated images was non-significant (P > .05) for the myocardium (2.06 vs 2.15 g/mL), but significant (P < .05) for the blood pool (.80 vs .86 g/mL). Non-gated images had the lowest coefficient of variation (27.3%), with significant increase for all other methods (31.6-32.5%). MoCo-4D showed smallest myocardial wall thickness (16.6 mm) with significant decrease compared to non-gated images (20.9 mm). Conclusions End-diastolic respiratory motion correction and 4D-CT resulted in improved motion minimization and image quality over standard dual-gating.

scholarly journals Magnetic resonance cholangiopancreatography with compressed sensing at 1.5 T: clinical application for the evaluation of branch duct IPMN of the pancreas

2020 ◽  
Vol 30 (11) ◽  
pp. 6014-6021
Author(s):  
Benjamin Henninger ◽  
Michael Steurer ◽  
Michaela Plaikner ◽  
Elisabeth Weiland ◽  
Werner Jaschke ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Image Quality ◽  
Compressed Sensing ◽  
Magnetic Resonance Cholangiopancreatography ◽  
Rank Test ◽  
Breath Hold ◽  
Branch Duct ◽  
Significant Difference ◽  
Lesion Conspicuity ◽  
Short Breath

Abstract Objectives To evaluate magnetic resonance cholangiopancreatography (MRCP) with compressed sensing (CS) for the assessment of branch duct intraductal papillary mucinous neoplasm (BD-IPMN) of the pancreas. For this purpose, conventional navigator-triggered (NT) sampling perfection with application-optimized contrast using different flip angle evolutions (SPACE) MRCP was compared with various CS-SPACE-MRCP sequences in a clinical setting. Methods A total of 41 patients (14 male, 27 female, mean age 68 years) underwent 1.5-T MRCP for the evaluation of BD-IPMN. The MRCP protocol consisted of the following sequences: conventional NT-SPACE-MRCP, CS-SPACE-MRCP with long (BHL, 17 s) and short single breath-hold (BHS, 8 s), and NT-CS-SPACE-MRCP. Two board-certified radiologists evaluated image quality, duct sharpness, duct visualization, lesion conspicuity, confidence, and communication with the main pancreatic duct in consensus using a 5-point scale (1–5), with higher scores indicating better quality/delineation/confidence. Maximum intensity projection reconstructions and originally acquired data were used for evaluation. Wilcoxon signed-rank test was used to compare the intra-individual difference between sequences. Results BHS-CS-SPACE-MRCP had the highest scores for image quality (3.85 ± 0.79), duct sharpness (3.81 ± 1.05), and duct visualization (3.81 ± 1.01). There was a significant difference compared with NT-CS-SPACE-MRCP (p < 0.05) but no significant difference to the standard NT-SPACE-MRCP (p > 0.05). Concerning diagnostic quality, BHS-CS-SPACE-MRCP had the highest scores in lesion conspicuity (3.95 ± 0.92), confidence (4.12 ± 1.08), and communication (3.8 ± 1.06), significantly higher compared with NT-SPACE-MRCP, BHL-SPACE-MRCP, and NT-CS-SPACE-MRCP (p = <0.05). Conclusions MRCP with CS 3D SPACE for the evaluation of BD-IPMN at 1.5 T provides the best results using a short breath-hold sequence. This approach is feasible and an excellent alternative to standard NT 3D MRCP sequences. Key Points • 1.5-T MRCP with compressed sensing for the evaluation of branch duct IPMN is a feasible method. • Short breath-hold sequences provide the best results for this purpose.

scholarly journals Self-navigated versus navigator-gated 3D MRI sequence for non-enhanced aortic root measurement in transcatheter aortic valve intervention

2021 ◽  
Vol 22 (Supplement_1) ◽  
Author(s):  
M Pamminger ◽  
C Kranewitter ◽  
C Kremser ◽  
M Reindl ◽  
SJ Reinstadler ◽  
...  
Keyword(s):  
Image Quality ◽  
Aortic Valve ◽  
Aortic Root ◽  
Signal To Noise Ratio ◽  
Three Dimensional ◽  
Acquisition Time ◽  
Kappa Statistics ◽  
Transcatheter Aortic Valve ◽  
Significant Difference ◽  
Noise Ratio

Abstract Funding Acknowledgements Type of funding sources: None. Background Preprocedural transcatheter aortic valve intervention (TAVI) evaluation requires reliable aortic root measurements for correct valve sizing. Purpose To prospectively compare image-quality, reliability and graft sizing of a prototype self-navigated and a navigator-gated non-contrast three dimensional (3D) whole-heart magnetic-resonance-angiography (MRA) sequence with computed-tomography-angiography (CTA) for planning transcatheter-aortic-valve-intervention (TAVI). Methods Self- and navigator-gated 1.5T MRA were performed in 27 patients (aged 83 ± 5 years, 41% male) for aortic root sizing and coronary ostia height measurements; 15 (56%) patients underwent additional CTA. Subjective-image quality was graded on a 4-point Likert scale, objective MRA image-quality was assessed by signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). Continuous MRA and CTA measurements were analyzed with regression and Bland-Altman analysis, valve sizing by kappa statistics. Results Median image-quality as rated by two observers was 1.5 [interquartile range (IQR) 1-3] for self-navigated MRA and 1 [IQR 1-2] for navigator-gated MRA (p = 0.059). SNR and CNR were comparable between MRA sequences (p = 0.471 and 0.445, respectively). Acquisition time was shorter for self-navigated MRA compared to navigator-gated MRA (5.5 ± 1 minutes vs, 6.5 ± 2 minutes, p = 0.029).  Inter-observer correlation of aortic root measurements was high to very high for both self- and navigator-gated MRA (r = 0.75 to 0.94 and r = 0.85 to 0.96, respectively, all p &lt; 0.0001). Theoretical prosthetic valve sizing of self-navigated MRA and CTA was equivalent (κ=1). However, in four patients (15%) one coronary ostium each (right coronary artery 3, left main artery 1) was not clearly definable on self-navigated MRA. Conclusion Self-navigated MRA enables aortic annulus TAVI measurements without significant difference to navigator-gated MRA at shortened acquisition time. Prosthesis sizing by self-navigated MRA measurements is equivalent to navigator-gated MRA and CTA-based choice. Abstract Figure.

Information capacity and bandwidth limitations in the SEM

1989 ◽  
Vol 47 ◽  
pp. 84-85
Author(s):  
D. C. Joy ◽  
R. D. Bunn
Keyword(s):  
Signal To Noise Ratio ◽  
Critical Dimension ◽  
Information Capacity ◽  
Acquisition Time ◽  
Signal To Noise ◽  
Sem Image ◽  
Probe Size ◽  
Minimum Number ◽  
Noise Ratio ◽  
Signal Channel

The information available from an SEM image is limited both by the inherent signal to noise ratio that characterizes the image and as a result of the transformations that it may undergo as it is passed through the amplifying circuits of the instrument. In applications such as Critical Dimension Metrology it is necessary to be able to quantify these limitations in order to be able to assess the likely precision of any measurement made with the microscope.The information capacity of an SEM signal, defined as the minimum number of bits needed to encode the output signal, depends on the signal to noise ratio of the image - which in turn depends on the probe size and source brightness and acquisition time per pixel - and on the efficiency of the specimen in producing the signal that is being observed. A detailed analysis of the secondary electron case shows that the information capacity C (bits/pixel) of the SEM signal channel could be written as :

Image Quality Enhancing by Efficient Histogram Equalization

2014 ◽  
Vol 2 (2) ◽  
pp. 47-58
Author(s):  
Ismail Sh. Baqer
Keyword(s):  
Image Quality ◽  
Contrast Enhancement ◽  
Mean Squared Error ◽  
Signal To Noise Ratio ◽  
Histogram Equalization ◽  
Gray Level ◽  
Signal To Noise ◽  
Squared Error ◽  
Noise Ratio

A two Level Image Quality enhancement is proposed in this paper. In the first level, Dualistic Sub-Image Histogram Equalization DSIHE method decomposes the original image into two sub-images based on median of original images. The second level deals with spikes shaped noise that may appear in the image after processing. We presents three methods of image enhancement GHE, LHE and proposed DSIHE that improve the visual quality of images. A comparative calculations is being carried out on above mentioned techniques to examine objective and subjective image quality parameters e.g. Peak Signal-to-Noise Ratio PSNR values, entropy H and mean squared error MSE to measure the quality of gray scale enhanced images. For handling gray-level images, convenient Histogram Equalization methods e.g. GHE and LHE tend to change the mean brightness of an image to middle level of the gray-level range limiting their appropriateness for contrast enhancement in consumer electronics such as TV monitors. The DSIHE methods seem to overcome this disadvantage as they tend to preserve both, the brightness and contrast enhancement. Experimental results show that the proposed technique gives better results in terms of Discrete Entropy, Signal to Noise ratio and Mean Squared Error values than the Global and Local histogram-based equalization methods

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