scholarly journals Fast 3D Isotropic Proton Density-Weighted Fat-Saturated MRI of the Knee at 1.5 T with Compressed Sensing: Comparison with Conventional Multiplanar 2D Sequences

2021 ◽  
Author(s):  
Christoph H.-J. Endler ◽  
Anton Faron ◽  
Alexander Isaak ◽  
Christoph Katemann ◽  
Narine Mesropyan ◽  
...  
Keyword(s):  
Image Quality ◽  
Compressed Sensing ◽  
Cruciate Ligament ◽  
Meniscal Tear ◽  
Three Dimensional ◽  
Acquisition Time ◽  
Proton Density ◽  
Image Sharpness ◽  
Multiplanar Reformation ◽  
Fat Saturation

Purpose Compressed sensing (CS) is a method to accelerate MRI acquisition by acquiring less data through undersampling of k-space. In this prospective study we aimed to evaluate whether a three-dimensional (3D) isotropic proton density-weighted fat saturated sequence (PDwFS) with CS can replace conventional multidirectional two-dimensional (2D) sequences at 1.5 Tesla. Materials and Methods 20 patients (45.2 ± 20.2 years; 10 women) with suspected internal knee damage received a 3D PDwFS with CS acceleration factor 8 (acquisition time: 4:11 min) in addition to standard three-plane 2D PDwFS sequences (acquisition time: 4:05 min + 3:03 min + 4:46 min = 11:54 min) at 1.5 Tesla. Scores for homogeneity of fat saturation, image sharpness, and artifacts were rated by two board-certified radiologists on the basis of 5-point Likert scales. Based on these ratings, an overall image quality score was generated. Additionally, quantitative contrast ratios for the menisci (MEN), the anterior (ACL) and the posterior cruciate ligament (PCL) in comparison with the popliteus muscle were calculated. Results The overall image quality was rated superior in 3D PDwFS compared to 2D PDwFS sequences (14.45 ± 0.83 vs. 12.85 ± 0.99; p < 0.01), particularly due to fewer artifacts (4.65 ± 0.67 vs. 3.65 ± 0.49; p < 0.01) and a more homogeneous fat saturation (4.95 ± 0.22 vs. 4.55 ± 0.51; p < 0.01). Scores for image sharpness were comparable (4.80 ± 0.41 vs. 4.65 ± 0.49; p = 0.30). Quantitative contrast ratios for all measured structures were superior in 3D PDwFS (MEN: p < 0.05; ACL: p = 0.06; PCL: p = 0.33). In one case a meniscal tear was only diagnosed using multiplanar reformation of 3D PDwFS, but it would have been missed on standard multiplanar 2D sequences. Conclusion An isotropic fat-saturated 3D PD sequence with CS enables fast and high-quality 3D imaging of the knee joint at 1.5 T and may replace conventional multiplanar 2D sequences. Besides faster image acquisition, the 3D sequence provides advantages in small structure imaging by multiplanar reformation. Key Points:  Citation Format

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 3D Dixon water-fat LGE imaging with image navigator and compressed sensing in cardiac MRI

2020 ◽  
Author(s):  
Martin Georg Zeilinger ◽  
Marco Wiesmüller ◽  
Christoph Forman ◽  
Michaela Schmidt ◽  
Camila Munoz ◽  
...  
Keyword(s):  
High Resolution ◽  
Image Quality ◽  
Compressed Sensing ◽  
Cardiac Mri ◽  
Three Dimensional ◽  
Fat Suppression ◽  
Diagnostic Confidence ◽  
Pericardial Disease ◽  
Scan Time ◽  
Wilcoxon Rank Sum Test

Abstract Objectives To evaluate an image-navigated isotropic high-resolution 3D late gadolinium enhancement (LGE) prototype sequence with compressed sensing and Dixon water-fat separation in a clinical routine setting. Material and methods Forty consecutive patients scheduled for cardiac MRI were enrolled prospectively and examined with 1.5 T MRI. Overall subjective image quality, LGE pattern and extent, diagnostic confidence for detection of LGE, and scan time were evaluated and compared to standard 2D LGE imaging. Robustness of Dixon fat suppression was evaluated for 3D Dixon LGE imaging. For statistical analysis, the non-parametric Wilcoxon rank sum test was performed. Results LGE was rated as ischemic in 9 patients and non-ischemic in 11 patients while it was absent in 20 patients. Image quality and diagnostic confidence were comparable between both techniques (p = 0.67 and p = 0.66, respectively). LGE extent with respect to segmental or transmural myocardial enhancement was identical between 2D and 3D (water-only and in-phase). LGE size was comparable (3D 8.4 ± 7.2 g, 2D 8.7 ± 7.3 g, p = 0.19). Good or excellent fat suppression was achieved in 93% of the 3D LGE datasets. In 6 patients with pericarditis, the 3D sequence with Dixon fat suppression allowed for a better detection of pericardial LGE. Scan duration was significantly longer for 3D imaging (2D median 9:32 min vs. 3D median 10:46 min, p = 0.001). Conclusion The 3D LGE sequence provides comparable LGE detection compared to 2D imaging and seems to be superior in evaluating the extent of pericardial involvement in patients suspected with pericarditis due to the robust Dixon fat suppression. Key Points • Three-dimensional LGE imaging provides high-resolution detection of myocardial scarring. • Robust Dixon water-fat separation aids in the assessment of pericardial disease. • The 2D image navigator technique enables 100% respiratory scan efficacy and permits predictable scan times.

scholarly journals Analisis Informasi Anatomi antara Sekuens T2WI FSE dan Proton Density Fat Saturation pada Pemeriksaan MRI Knee Joint Potongan Sagital (Studi pada Anterior Cruciate Ligament (ACL) dan Posterior Cruciate Ligament (PCL))

2016 ◽  
Vol 2 (2) ◽  
pp. 175-179
Author(s):  
Atina Izzah Kusumaningrum ◽  
Lidya Purna WS Kuntjoro ◽  
Gatot Murti Wibowo
Keyword(s):  
Anterior Cruciate Ligament ◽  
Knee Joint ◽  
Posterior Cruciate Ligament ◽  
Cruciate Ligament ◽  
Proton Density ◽  
Border Line ◽  
Fat Saturation ◽  
Anterior Cruciate ◽  
Anatomical Information ◽  
Mri Knee

Background: There are clinical situations that radiology physicians need to assess Anterior Cruciate Ligament (ACL) and Posterior Cruciate Ligament (PCL) clearly with the two typical sequences (T2WI FSE sequence and Proton Density Fat Saturation). However, a slight difference in using the applied sequences will result different levels of image quality information. The aim of this study is to compare clinical  manifest in anatomical information on the resulted images between  T2WI FSE sequence and Proton Density Fat Saturation and to define the best sequence that fit to reveal ACL and PCL of the knee joint..Methods: The research was an experimental quasy. 20 sagital slices of  the knee jointMRI were acquired from 10 volunteers who underwent MRI examinations with the two methods (T2WI FSE and Proton Density Fat Saturation). 3 experienced radiology physicians blended in the image scoring when review ACL and PCL appearances on knee MRI images. Inter-observer suitability was checked with Kappa test. A non-parametric Wilcoxon analyses was the statistical tool to test the null hypothesis.Results: The result showed a significant difference in anatomical information of ACL and PCL when T2WI FSE and Proton Density Fat Saturation sequences applied on the MRI of the knee jointsagital slices (p-value 0,05). The mean rank of T2WI FSE was better than Proton Density Fat Saturation  which contributed to the value at 4,50. There was an increase in signals that lead to ACL and PCL appear to be more hyper-intens compared to sorrounding organs in general, except the border line  of PCL.  By this means, it was useful for evaluating the patient whose particularly with ACL post-grafting.Conclusion: There was the difference in anatomical information between T2WI FSE sequence and Proton Density Fat Saturation on MRI knee jointwith sagital slices for ACL and PCL studies.  T2WI FSE sequence was the best method for showing anatomical information of ACL and PCL, although a relative low signal still occured from border line  of PCL.

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.

scholarly journals Compressed sensing-based super-resolution ultrasound imaging for faster acquisition and high quality images

2020 ◽  
Author(s):  
Jihun Kim ◽  
Qingfei Wang ◽  
Siyuan Zhang ◽  
Sangpil Yoon
Keyword(s):  
Image Quality ◽  
Compressed Sensing ◽  
Ultrasound Imaging ◽  
Imaging Technique ◽  
Super Resolution ◽  
Tumor Model ◽  
Acquisition Time ◽  
Mouse Tumor ◽  
Conventional Ultrasound

AbstractSuper-resolution ultrasound (SRUS) imaging technique has overcome the diffraction limit of conventional ultrasound imaging, resulting in an improved spatial resolution while preserving imaging depth. Typical SRUS images are reconstructed by localizing ultrasound microbubbles (MBs) injected in a vessel using normalized 2-dimensional cross-correlation (2DCC) between MBs signals and the point spread function of the system. However, current techniques require isolated MBs in a confined area due to inaccurate localization of densely populated MBs. To overcome this limitation, we developed the ℓ1-homotopy based compressed sensing (L1H-CS) based SRUS imaging technique which localizes densely populated MBs to visualize microvasculature in vivo. To evaluate the performance of L1H-CS, we compared the performance of 2DCC, interior-point method based compressed sensing (CVX-CS), and L1H-CS algorithms. Localization efficiency was compared using axially and laterally aligned point targets (PTs) with known distances and randomly distributed PTs generated by simulation. We developed post-processing techniques including clutter reduction, noise equalization, motion compensation, and spatiotemporal noise filtering for in vivo imaging. We then validated the capabilities of L1H-CS based SRUS imaging technique with high-density MBs in a mouse tumor model, kidney, and zebrafish dorsal trunk, and brain. Compared to 2DCC, and CVX-CS algorithm, L1H-CS algorithm, considerable improvement in SRUS image quality and data acquisition time was achieved. These results demonstrate that the L1H-CS based SRUS imaging technique has the potential to examine the microvasculature with reduced acquisition and reconstruction time of SRUS image with enhanced image quality, which may be necessary to translate it into the clinics.

scholarly journals Artifact Reduction in Compressed Sensing Averaging Techniques for High-Resolution Magnetic Resonance Images

2021 ◽  
Vol 11 (21) ◽  
pp. 9802
Author(s):  
Jeong-Min Shim ◽  
Young-Bo Kim ◽  
Chang-Ki Kang
Keyword(s):  
Compressed Sensing ◽  
High Frequency ◽  
Transfer Functions ◽  
Magnetic Resonance Images ◽  
Acquisition Time ◽  
Modulation Transfer ◽  
Image Sharpness ◽  
Spatiotemporal Resolution ◽  
Ringing Artifacts ◽  
Ringing Artifact

This study aims to introduce a new compressed sensing averaging (CSA) technique for the reduction of blurring and/or ringing artifacts, depending on the k-space sampling ratio. A full k-space dataset and three randomly undersampled datasets were obtained for CSA images in a brain phantom and a healthy subject. An additional simulation was performed to assess the effect of the undersampling ratio on the images and the signal-to-noise ratios (SNRs). The image sharpness, spatial resolution, and contrast between tissues were analyzed and compared with other CSA techniques. Compared to CSA with multiple acquisition (CSAM) at 25%, 35%, and 45% undersampling, the reduction rates of the k-space lines of CSA with keyhole (CSAK) were 10%, 15%, and 22%, respectively, and the acquisition time was reduced by 16%, 23%, and 32%, respectively. In the simulation performed with a full sampling k-space dataset, the SNR decreased to 10.41, 9.80, and 8.86 in the white matter and 9.69, 9.35, and 8.46 in the gray matter, respectively. In addition, the ringing artifacts became substantially more predominant as the number of sampling lines decreased. The 50% modulation transfer functions were 0.38, 0.43, and 0.54 line pairs per millimeter for CSAM, CSAK with high-frequency sharing (CSAKS), and CSAK with high-frequency copying (CSAKC), respectively. In this study, we demonstrated that the smaller the sampling line, the more severe the ringing artifact, and that the CSAKC technique proposed to overcome the artifacts that occur when using CSA techniques did not generate artifacts, while it increased spatiotemporal resolution.

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.

Effect of different multiplanar reformation algorithms on image quality of intraoperative three-dimensional fluoroscopy

2019 ◽  
Vol 44 (7) ◽  
pp. 738-744
Author(s):  
Isabel Graul ◽  
Ivan Marintschev ◽  
Sascha Rausch ◽  
Niklas Eckart ◽  
Gunther O. Hofmann ◽  
...  
Keyword(s):  
Image Quality ◽  
Three Dimensional ◽  
Fracture Reduction ◽  
Data Sets ◽  
Radius Fractures ◽  
Multiplanar Reformation ◽  
Data Set ◽  
Implant Positioning ◽  
Processing Algorithms

Different multiplanar reformation (MPR-512 and -256) algorithms of intraoperative acquired 3-D-fluoroscopy data exist without recommendations for use in the literature. To compare algorithms, 3-D-fluoroscopic data sets of 46 radius fractures were blinded and processed using MPR-256 and -512 (Ziehm, Vision-Vario 3D). Each reformatted data set was analysed to evaluate image quality, fracture reduction quality and screw misplacements. Overall image quality was higher rated in the MPR-512 compared with the MPR-256 (3.2 vs. 2.2 points, scale 1–5 points), accompanied by a reduced number of scans that could not be analysed (10 vs. 19%). Interobserver evaluation of fracture reduction quality was fair to moderate (independent of the algorithm). In contrast, for screw misplacements MPR-depended ratings were found (MPR-256: fair to moderate; MPR-512: moderate to substantial). Optimization of post-processing algorithms, rather than modifications of image acquisition, may increase the image quality for assessing implant positioning, but limitations in evaluating fracture reduction quality still exist.

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