Vaddadi Venkatesh, Raji Susan Mathew, Phaneendra K Yalavarthy
OBJECTIVE: Quantitative susceptibility mapping (QSM) provides an estimate of the magnetic susceptibility of tissue using magnetic resonance (MR) phase measurements. The tissue magnetic susceptibility (source) from the measured magnetic field distribution/local tissue field (effect) inherent in the MR phase images is estimated by numerically solving the inverse source-effect problem. This study aims to develop an effective model-based deep-learning framework to solve the inverse problem of QSM...
April 10, 2024: Magma
Shun Kitano, Yuki Kanazawa, Masafumi Harada, Yo Taniguchi, Hiroaki Hayashi, Yuki Matsumoto, Kosuke Ito, Yoshitaka Bito, Akihiro Haga
OBJECTIVE: To clarify the relationship between myelin water fraction (MWF) and R1 ⋅R2 * and to develop a method to calculate MWF directly from parameters derived from QPM, i.e., MWF converted from QPM (MWFQPM ). MATERIALS AND METHODS: Subjects were 12 healthy volunteers. On a 3 T MR scanner, dataset was acquired using spoiled gradient-echo sequence for QPM. MWF and R1 ⋅R2 * maps were derived from the multi-gradient-echo (mGRE) dataset. Volume-of-interest (VOI) analysis using the JHU-white matter (WM) atlas was performed...
April 6, 2024: Magma
Wenbo Sun, Dan Xu, Huan Li, Sirui Li, Qingjia Bao, Xiaopeng Song, Daniel Topgaard, Haibo Xu
OBJECTIVE: To assess the performance of hybrid multi-dimensional magnetic resonance imaging (HM-MRI) in quantifying hematoxylin and eosin (H&E) staining results, grading and predicting isocitrate dehydrogenase (IDH) mutation status of gliomas. MATERIALS AND METHODS: Included were 71 glioma patients (mean age, 50.17 ± 13.38 years; 35 men). HM-MRI images were collected at five different echo times (80-200 ms) with seven b-values (0-3000 s/mm2 )...
April 5, 2024: Magma
Yoshihiko Tachikawa, Hiroshi Hamano, Naoya Chiwata, Hikaru Yoshikai, Kento Ikeda, Yasunori Maki, Yukihiko Takahashi, Makiko Koike
OBJECTIVES: To evaluate a new motion correction method, named RT + NV Track, for upper abdominal DWI that combines the respiratory triggering (RT) method using a respiration sensor and the Navigator Track (NV Track) method using navigator echoes. MATERIALS AND METHODS: To evaluate image quality acquired upper abdominal DWI and ADC images with RT, NV, and RT + NV Track in 10 healthy volunteers and 35 patients, signal-to-noise efficiency (SNRefficiency ) and the coefficient of variation (CV) of ADC values were measured...
February 24, 2024: Magma
Ana R Fouto, Rafael N Henriques, Marc Golub, Andreia C Freitas, Amparo Ruiz-Tagle, Inês Esteves, Raquel Gil-Gouveia, Nuno A Silva, Pedro Vilela, Patrícia Figueiredo, Rita G Nunes
OBJECTIVE: Diffusional kurtosis imaging (DKI) extends diffusion tensor imaging (DTI), characterizing non-Gaussian diffusion effects but requires longer acquisition times. To ensure the robustness of DKI parameters, data acquisition ordering should be optimized allowing for scan interruptions or shortening. Three methodologies were used to examine how reduced diffusion MRI scans impact DKI histogram-metrics: 1) the electrostatic repulsion model (OptEEM ); 2) spherical codes (OptSC ); 3) random (RandomTRUNC )...
February 23, 2024: Magma
Uten Yarach, Itthi Chatnuntawech, Kawin Setsompop, Atita Suwannasak, Salita Angkurawaranon, Chakri Madla, Charuk Hanprasertpong, Prapatsorn Sangpin
PURPOSE: Propeller fast-spin-echo diffusion magnetic resonance imaging (FSE-dMRI) is essential for the diagnosis of Cholesteatoma. However, at clinical 1.5 T MRI, its signal-to-noise ratio (SNR) remains relatively low. To gain sufficient SNR, signal averaging (number of excitations, NEX) is usually used with the cost of prolonged scan time. In this work, we leveraged the benefits of Locally Low Rank (LLR) constrained reconstruction to enhance the SNR. Furthermore, we enhanced both the speed and SNR by employing Convolutional Neural Networks (CNNs) for the accelerated PROPELLER FSE-dMRI on a 1...
February 22, 2024: Magma
Hongyan He, Shufeng Wei, Huixian Wang, Wenhui Yang
OBJECTIVE: Conventional single-target field control for matrix gradient coils will add control complexity in MRI spatial encoding, such as designing specialized fields and sequences. This complexity can be reduced by multi-target field control, which is realized by optimizing the coil structure according to target fields. METHODS: Based on the principle of multi-target field control, the X, Y and Z gradient fields can be set as target fields, and all coil elements can then be divided into three groups to generate these fields...
February 22, 2024: Magma
Paweł Wierzba, Anna Sękowska-Namiotko, Agnieszka Sabisz, Monika Kosowska, Lina Jing, Robert Bogdanowicz, Małgorzata Szczerska
No abstract text is available yet for this article.
February 22, 2024: Magma
Zijian Zhou, Peng Hu, Haikun Qi
Subject motion is a long-standing problem of magnetic resonance imaging (MRI), which can seriously deteriorate the image quality. Various prospective and retrospective methods have been proposed for MRI motion correction, among which deep learning approaches have achieved state-of-the-art motion correction performance. This survey paper aims to provide a comprehensive review of deep learning-based MRI motion correction methods. Neural networks used for motion artifacts reduction and motion estimation in the image domain or frequency domain are detailed...
February 22, 2024: Magma
Marco Parillo, Carlo Augusto Mallio, Ilona A Dekkers, Àlex Rovira, Aart J van der Molen, Carlo Cosimo Quattrocchi
The acquisition of images minutes or even hours after intravenous extracellular gadolinium-based contrast agents (GBCA) administration ("Late/Delayed Gadolinium Enhancement" imaging; in this review, further termed LGE) has gained significant prominence in recent years in magnetic resonance imaging. The major limitation of LGE is the long examination time; thus, it becomes necessary to understand when it is worth waiting time after the intravenous injection of GBCA and which additional information comes from LGE...
February 22, 2024: Magma
Christian Karl Eisen, Patrick Liebig, Jürgen Herrler, Dieter Ritter, Simon Lévy, Michael Uder, Armin Michael Nagel, David Grodzki
OBJECTIVE: To compensate subject-specific field inhomogeneities and enhance fat pre-saturation with a fast online individual spectral-spatial (SPSP) single-channel pulse design. METHODS: The RF shape is calculated online using subject-specific field maps and a predefined excitation k-space trajectory. Calculation acceleration options are explored to increase clinical viability. Four optimization configurations are compared to a standard Gaussian spectral selective pre-saturation pulse and to a Dixon acquisition using phantom and volunteer (N = 5) data at 1...
February 17, 2024: Magma
Houchun H Hu, Henry Szu-Meng Chen, Diego Hernando
OBJECTIVE: Performance assessments of quantitative determinations of proton density fat fraction (PDFF) have largely focused on the range between 0 and 50%. We evaluate PDFF in a two-site phantom study across the full 0-100% PDFF range. MATERIALS AND METHODS: We used commercially available 3D chemical-shift-encoded water-fat MRI sequences from three MRI system vendors at 1.5T and 3T and conducted the study across two sites. A spherical phantom housing 18 vials spanning the full 0-100% PDFF range was used...
February 13, 2024: Magma
Zhaohuan Zhang, Elif Aygun, Shu-Fu Shih, Steven S Raman, Kyunghyun Sung, Holden H Wu
OBJECTIVE: To develop and evaluate a technique combining eddy current-nulled convex optimized diffusion encoding (ENCODE) with random matrix theory (RMT)-based denoising to accelerate and improve the apparent signal-to-noise ratio (aSNR) and apparent diffusion coefficient (ADC) mapping in high-resolution prostate diffusion-weighted MRI (DWI). MATERIALS AND METHODS: Eleven subjects with clinical suspicion of prostate cancer were scanned at 3T with high-resolution (HR) (in-plane: 1...
February 13, 2024: Magma
Minbo Jiang, Shuai Wang, Zhiwei Song, Limei Song, Yi Wang, Chuanzhen Zhu, Qiang Zheng
OBJECTIVES: CT and MR are often needed to determine the location and extent of brain lesions collectively to improve diagnosis. However, patients with acute brain diseases cannot complete the MRI examination within a short time. The aim of the study is to devise a cross-device and cross-modal medical image synthesis (MIS) method Cross2 SynNet for synthesizing routine brain MRI sequences of T1WI, T2WI, FLAIR, and DWI from CT with stroke and brain tumors. MATERIALS AND METHODS: For the retrospective study, the participants covered four different diseases of cerebral ischemic stroke (CIS-cohort), cerebral hemorrhage (CH-cohort), meningioma (M-cohort), glioma (G-cohort)...
February 5, 2024: Magma
Sevgi Gokce Kafali, Shu-Fu Shih, Xinzhou Li, Grace Hyun J Kim, Tristan Kelly, Shilpy Chowdhury, Spencer Loong, Jeremy Moretz, Samuel R Barnes, Zhaoping Li, Holden H Wu
OBJECTIVE: Increased subcutaneous and visceral adipose tissue (SAT/VAT) volume is associated with risk for cardiometabolic diseases. This work aimed to develop and evaluate automated abdominal SAT/VAT segmentation on longitudinal MRI in adults with overweight/obesity using attention-based competitive dense (ACD) 3D U-Net and 3D nnU-Net with full field-of-view volumetric multi-contrast inputs. MATERIALS AND METHODS: 920 adults with overweight/obesity were scanned twice at multiple 3 T MRI scanners and institutions...
February 1, 2024: Magma
Zhen Tang, Sasan Mahmoodi, Di Meng, Angela Darekar, Brigitte Vollmer
OBJECTIVE: Susceptibility weighted imaging (SWI) of neonatal hypoxic-ischemic brain injury can provide assistance in the prognosis of neonatal hypoxic-ischemic encephalopathy (HIE). We propose a convolutional neural network model to classify SWI images with HIE. MATERIALS AND METHODS: Due to the lack of a large dataset, transfer learning method with fine-tuning a pre-trained ResNet 50 is introduced. We randomly select 11 datasets from patients with normal neurology outcomes (n = 31) and patients with abnormal neurology outcomes (n = 11) at 24 months of age to avoid bias in classification due to any imbalance in the data...
January 22, 2024: Magma
Anna Marriott, James Rioux, Kimberly Brewer
OBJECTIVE: MR fingerprinting (MRF) can enable preclinical studies of cell tracking by quantifying multiple contrast agents simultaneously, but faster scan times are required for in vivo applications. Sliding window (SW)-MRF is one option for accelerating MRF, but standard implementations are not sufficient to preserve the accuracy of T2 *, which is critical for tracking iron-labelled cells in vivo. PURPOSE: To develop a SW approach to MRF which preserves the T2 * accuracy required for accelerated concentration mapping of iron-labelled cells on single-channel preclinical systems...
January 13, 2024: Magma
Malte Roehl, Miriam Conway, Sarah Ghonim, Pedro F Ferreira, Sonia Nielles-Vallespin, Sonya V Babu-Narayan, Dudley J Pennell, Peter D Gatehouse, Andrew D Scott
OBJECTIVE: The excellent blood and fat suppression of stimulated echo acquisition mode (STEAM) can be combined with saturation recovery single-shot acquisition (SASHA) in a novel STEAM-SASHA sequence for right ventricular (RV) native T1 mapping. MATERIALS AND METHODS: STEAM-SASHA splits magnetization preparation over two cardiac cycles, nulling blood signal and allowing fat signal to decay. Breath-hold T1 mapping was performed in a T1 phantom and twice in 10 volunteers using STEAM-SASHA and a modified Look-Locker sequence at peak systole at 3T...
January 12, 2024: Magma
Dominik Daniel Gabbert, Lennart Petersen, Abigail Burleigh, Simona Boroni Grazioli, Sylvia Krupickova, Reinhard Koch, Anselm Sebastian Uebing, Monty Santarossa, Inga Voges
OBJECTIVE: The prospect of being able to gain relevant information from cardiovascular magnetic resonance (CMR) image analysis automatically opens up new potential to assist the evaluating physician. For machine-learning-based classification of complex congenital heart disease, only few studies have used CMR. MATERIALS AND METHODS: This study presents a tailor-made neural network architecture for detection of 7 distinctive anatomic landmarks in CMR images of patients with hypoplastic left heart syndrome (HLHS) in Fontan circulation or healthy controls and demonstrates the potential of the spatial arrangement of the landmarks to identify HLHS...
January 12, 2024: Magma
Nicolas Boulant, Caroline Le Ster, Alexis Amadon, Guy Aubert, Alexander Beckett, Jean Belorgey, Cédric Bonnelye, Dario Bosch, David Otto Brunner, Guillaume Dilasser, Olivier Dubois, Philipp Ehses, David Feinberg, Sajjad Feizollah, Vincent Gras, Simon Gross, Quentin Guihard, Hervé Lannou, Denis Le Bihan, Franck Mauconduit, Frédéric Molinié, François Nunio, Klaas Pruessmann, Lionel Quettier, Klaus Scheffler, Tony Stöcker, Christine Tardif, Kamil Ugurbil, Alexandre Vignaud, An Vu, Xiaoping Wu
OBJECTIVE: To assess the possible influence of third-order shim coils on the behavior of the gradient field and in gradient-magnet interactions at 7 T and above. MATERIALS AND METHODS: Gradient impulse response function measurements were performed at 5 sites spanning field strengths from 7 to 11.7 T, all of them sharing the same exact whole-body gradient coil design. Mechanical fixation and boundary conditions of the gradient coil were altered in several ways at one site to study the impact of mechanical coupling with the magnet on the field perturbations...
January 10, 2024: Magma
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