bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigating the effect of reduced TR in detection of RSNs at a low field MR scanner
Authors: Halder Arjama , de Paula Demetrius Riberio , Handler William , Soddu Andrea , Chronik Blaine
Published: August 2023

Initial investigation of effects due to reduced TR on RSNs at a 0.5 T MR scanner. There was a decrease in detected regions within specific networks for the 3 T data as TR was reduced. However, when the tSNR was approximately 17 ignoring the expected decrement of detected regions compared to the 3 T data, there was an increase in positive detection at shorter TR. These result show the possibility of extracting true RSNs for a low field scanner using shorter TRs which can lead to efficient sequence design since T1 is shortened at low fields.
Development of a Low Field Tabletop Micro-MRI systemUsing Novel Solid-State Hyperpolarization of Water
Authors: Buchanan Emily , Stupic Karl , Russek Stephen
Published: August 2023

Micro-MRI systems could have transformational applications in pathology and personalized medicine if substantial technological challenges are overcome: resolution needs to be improved from current state-of-the-art to subcellular resolution <10$$$\mu$$$m, contrast needs to be improved to allow delineation of cells and cell structures, and systems need to be miniaturized from the large high-field superconducting-magnet systems to low-cost tabletop systems. A key enabling component is likely to be a room-temperature low-field point-of-use hyperpolarization system. Here we present a tabletop 135mT micro-MRI system that uses a novel solid-state point-of-use water proton hyperpolarization system integrated into the imaging cell that functions as a bioreactor.
Flexible six-channel knee array for MRI at 0.55T
Authors: Wang Bili , Siddiq Syed , Walczyk Jerzy , Bruno Mary , Fritz Jan , Khodarahmi Iman , Brinkmann Inge , Rehner Robert , Lakshmanan Karthik , Brown Ryan
Published: August 2023

New-generation 0.55T systems require a suite of tailored coils to preserve image quality that is expected from higher field systems. We built a six-channel coil array for knee MRI using RG58 coaxial cable loops, which have adequate mechanical flexibility to wrap tightly around the leg and suitably low conductive loss at 23.55MHz. Initial findings show that the dedicated coil outperformed a general-purpose counterpart and suggest that clinical quality knee imaging is feasible.
Phantom Development for Comparison of Thermal Mapping
Authors: Martinez Diego , Wiens Curtis , Louka Amgad , Gignac Dereck , Handler Will , Chronik Blaine
Published: August 2023

Thermal Mapping using MRI is a non-invasive method for probing the body and has both diagnostic and interventional applications. If conducted on more accessible low field strength systems, these can improve the accessibility of the method for wider use. In order to validate and compare thermal mapping, a temperature control phantom was developed with tools for heating the phantom and externally tracking the temperature of the phantom. A heating study was performed with the phantom at two temperatures, and the thermometry methods showed good connection to the change in temperature in the phantom.
Machine learning for detecting intracranial dural arteriovenous fistula on susceptibility weighted image using a convolutional neural network
Authors: Thomas Bejoy , S Jithin S , Anzar Ajimi mol , Kannath Santhosh
Published: August 2023

Artificial intelligence techniques are widely used in medical imaging and diagnostics. In this retrospective study, a convolutional neural network (CNN) architecture was developed to classify intracranial dural arteriovenous fistula (DAVF) on Susceptibility Weighted Images (SWI). The dataset used was a total of 3965 SWI image slices of DAVF patients and 4380 images of controls. The proposed classifier showed significant accuracy in the diagnosis of DAVF and it could be developed as a computer assisted diagnosis tool to identify unsuspected DAVF in routine MR imaging.
Analyzing Task-based fMRI Time Series using Machine Learning
Authors: Kuan Elaine , Vegh Viktor , O'Brien Kieran , Hammond Amanda , Yaksic Javier Urriola , Reutens David
Published: August 2023

Common approaches for analyzing task-based fMRI data rely upon the use of regressors, which in some experimental paradigms are difficult to define. A machine learning method is proposed to overcome this challenge. Three machine learning methods with established utility for time series classification were used to classify areas of activation and non-activation in a language fMRI study. Machine learning methods were able to identify the activation regions identified by analyses using the General Linear Model (GLM). Machine learning may be useful for fMRI time series analysis, particularly when regressors required for GLM-based analyses are difficult to define.
Imaging grey and white matter microstructure simultaneously on a clinical scanner is now possible
Authors: Schiavi Simona , Palombo Marco , Zacà Domenico , Tazza Francesco , Lapucci Caterina , Castellan Lucio , Costagli Mauro , Inglese Matilde
Published: August 2023

Diffusion MRI is a powerful technique that, thanks to advanced signal modelling like the Soma And Neurite Density Image (SANDI) can probe microstrucutral information of both grey and white matter. However, this model requires multishell acquisitions including b-values that are at least 6 times higher than those used in clinical practice. Here we propose a 10-minute acquisition protocol that enables to acquire such images on a clinical 3T scanner. We show the reproducibility of our approach on five healthy subjects as well as potential clinical impact on two subjects affected by multiple sclerosis.
Parameter Optimization for High-Resolution MR Elastography of the Human Brain at 7T
Authors: Triolo Emily , Khegai Oleksandr , Veraart Jelle , Alipour Akbar , Hedden Trey , Kurt Mehmet , Balchandani Priti
Published: August 2023

MRE, a technique used to characterize the viscoelasticity of tissues, is typically performed at 3T for the human brain. MRE at 7T has the promise to deliver higher resolution, however, is subject to several artifacts and limitations. Here, we developed and tested an MRE setup and sequence at 7T on one subject at three different resolutions to investigate how both changing resolution and using MP-PCA denoising affects the estimated shear modulus (|G*|). Our pilot study has shown an increase in OSS-SNR after using MP-PCA denoising, and has demonstrated a relationship between resolution, OSS-SNR, and |G*| that requires further investigation.
A radiomics approach to assess high risk carotid plaques: a non-invasive imaging biomarker, retrospective study
Authors: Chen Sihan , Zha Yunfei , Liu Changsheng , chen Xixiang , ma Ling , Liu Weiyin
Published: August 2023

This study aimed to construct a radiomics-based T2-weighted imaging (T2WI) approach from high-resolution multi-contrast magnetic resonance imaging (hrMRI) in combination with clinical high-risk factors for non-invasive assessment, to differentiate symptomatic carotid atherosclerotic plaques from asymptomatic ones. Radscore showed a better diagnostic performance. The combination model of texture features and clinical data had the best performance in assessment of lesion vulnerability. This study demonstrated that hrMRI radiomics features provided incremental value for assessment of the carotid atherosclerotic vulnerability.
Microstructural Reorganizations in Thalamic Nuclei Across Characteristics of Temporal Lobe Epilepsy
Authors: Kang KiChang , Sathe Anish , Ailes Isaiah , Shelley India , Syed Mashaal , Miller Christopher , Mohamed Feroze , Sharan Ashwini , Alizadeh Mahdi
Published: August 2023

Temporal lobe epilepsy (TLE) is the most common form of epilepsy which can become medically refractory and referred for surgery. The thalamus has been shown to demonstrate both structural and functional changes in TLE. However, little is known about microstructural alterations within individual thalamic nuclei. In this study, we used diffusion tensor imaging (DTI) to determine if subjects with unilateral TLE demonstrate hemispheric and intra-hemispheric differences in thalamic nuclei across clinical characteristics. We report statistically significant differences in nuclei in subjects with tonic-clonic seizures and mesial temporal sclerosis in both hemispheric and intra-hemispheric comparisons.
Imaging the hypothalamus in Prader-Willi Syndrome
Authors: Brown Stephanie , Manning Katherine , Holland Anthony
Published: August 2023

Prader-Willi Syndrome (PWS) is a neurodevelopmental disorder characterised by intellectual disability, emotional dysregulation and importantly, marked overeating behaviour. The hypothalamus controls food intake and satiety by endocrine control, and evidence from animal studies has shown that lesions of the hypothalamic nuclei result in hyperphagia. However, studies examining the hypothalamus in humans in vivo are scarce. We show here significantly lower volumes of the hypothalamus and hypothalamic nuclei in PWS compared to healthy controls and general population obese individuals. Our findings are strongly suggestive that impaired appetite control and problematic eating behaviours are a consequence of abnormal hypothalamic structure in PWS.
Diagnostic performance of histological fibrous capsule and pseudocapsule (a false-positive fibrous capsule) in hepatocellular carcinoma
Authors: Higaki Atsushi , Yamamoto Akira , Fukunaga Takeshi , Nishimura Hirotake , Kanki Akihiko , Tamada Tsutomu
Published: August 2023

We used contrast-enhanced MRI and CT to evaluate the diagnostic potential of histological fibrous capsule and pseudocapsule in HCC. 51.4% (36/70) of HCCs had capsules, and pseudocapsule was found in 35.3% (18/51) of lesions with enhancing capsule imaging. Among the various imaging features, T1WI low signal rim, arterial phase low signal capsule, enhancing capsule on MRI and CT, and tumor margin enlargement sign on HBP were useful in diagnosing fibrous capsules. Among these, tumor margin enlargement sign on HBP showed the highest accuracy for the diagnosis of capsule, and was the only finding that could diagnose pseudocapsule.
Clinical value of MRI-detected extramural vascular invasion in predicting distant metastasis of rectal cancer
Authors: Cui Tang , Xu Jinming , Lin Moubin , Qiu Shixiong , Zuo Xiaoming , Liu Mengxiao , Wang Peijun
Published: August 2023

The results of the present study suggest that there was a significant difference in the occurrence of distant metastasis between RC patients with or without mrEMVI, CRM invasion, regional LN metastasis, and MR peritoneal reflex involvement. And mrEMVI and regional LN metastasis were independent risk factors for distant metastasis of rectal cancer. Therefore, MRI can be used to observe the status of EMVI before surgery, which is helpful for the formulation of individualized treatment plans for rectal cancer and assessment of prognosis.
MRI Correlation with Liver Explant Pathology: LIRADS Treatment Response Algorithm for Residual HCC After Y-90 Therapy
Authors: Harwood Matthew , Parikh Parth , Clinkenbeard Alexander , Naidu Sailen , Salomao Marcela , Silva Alvin
Published: August 2023

The liver imaging and reporting data system treatment response algorithm (LIRADS TRA) for CT and MRI has been used to predict residual viable tumor after treatment with yttrium-90 (Y-90). This single-center cohort of 20 patients were reviewed using the LIRADS TRA assessing residual viable tumor following Y-90 therapy. Pathology of subsequent liver explants was the reference standard. The LIRADS TRA predicted positive treatment effect (nonviable): NPV 82.4% (95% CI 0.47-1.55), accuracy 75% (72.0-89.4). The results of this preliminary study will need further validation in a larger, similar, pathologic-confirmed cohort.
Does Functional Parameters from Gadoxetic Acid–enhanced MRI Predict Decompensation in Cirrhosis?
Authors: ZHANG Xueqin , ZHANG Tao , XU Lei , ZHAO Xiance
Published: August 2023

We used Look-Locker sequences to acquire T1 mapping images pre and post-contrast at 20 minutes after gadoxetic acid administration. Liver-to-spleen contrast index (LSI), contrast uptake index (CUI), relative liver enhancement (RLE), hepatocyte fraction (HeF), T1 relaxation times on unenhanced phase (T1unenh), T1 relaxation times on hepatobiliary phase (T1HBP), reduction rates of T1 relaxation times (rrT1), and the functional liver imaging score (FLIS) of the liver were measured and calculated by two radiologists independently. Our study showed that LSI, CUI, HeF, T1HBP, rrT1 and FLIS based on gadoxetic acid–enhanced MRI are help for the evaluation of liver function.
Sex-specific differences in the relationships between obesity, cerebral perfusion and grey matter volume
Authors: Intzandt Brittany , Sanami Safa , Huck Julia , Hoge Rick , Group PREVENT-AD Research , Bherer Louis , Gauthier Claudine
Published: August 2023

Cerebral health declines in aging. Obesity is reported to accentuate, reduce or have no effect on these declines. Given sex differences are present for cerebral health and obesity individually, it is hypothesized these discrepancies are influenced by sex. Here, we investigated the relationship between obesity, cerebral structure and perfusion in aging females and males separately. Females revealed greater obesity was associated with increased structure and perfusion. Males demonstrated a positive relationship with obesity and perfusion, however, an inverse association was identified between structure and obesity. Future work should investigate the influence of other lifestyle factors on these sex-specific relationships
The primate corpus callosum - Age-related differences in morphology and microstructure
Authors: Dadarwal Rakshit , Mylius Judith , Moussavi Amir , Boretius Susann
Published: August 2023

Aging of the brain has been associated with several structural and functional changes, including tissue volume loss, white matter integrity loss, and changes in iron concentration. However, the fundamental mechanism driving these changes and their significance in the development of age-related neurodegenerative diseases are still not very well understood. Due to their unequivocal similarity with humans, non-human primates may be of particular value to further explore these mechanisms. In this study, we looked at age-related morphological, tissue microstructural, and iron-concentration changes in the corpus callosum of macaques and marmosets.
Accelerated 3D EPI navigator for prospective motion correction
Authors: Chang Yulin , Splitthoff Daniel , Lo Wei-ching , Tisdall M. , van der Kouwe Andre
Published: August 2023

We show that for navigator-based prospective motion correction MRI, acceleration of 3D EPI acquisition increases sequence flexibility and improves the navigator image quality without sacrificing the quality of motion correction.
Prospective motion correction in multi-inversion EPI using volumetric navigators for robust T1 map estimation
Authors: Polimeni Jonathan , Tisdall M. , Park Daniel , Wighton Paul , Frost S. , Tardif Christine , van der Kouwe Andre
Published: August 2023

In multi-inversion EPI (MI-EPI), each slice samples a distinct inversion time during each inversion recovery, providing an efficient method for estimating T1. MI-EPI is vulnerable to through-plane motion, which results in slices sampling a subset of the desired inversion times and wrong TIs will be attributed to the slices. This cannot be corrected retrospectively. We introduce prospective motion correction in MI-EPI using volumetric navigators (vNavs). vNavs are acquired at the beginning of the inversion recovery thus the effects of their excitation pulses must be modeled for T1 estimation. This provides improved T1 estimation accuracy in the presence of subject motion.
Gaussian Process Modelling and Compensation of Motion in DCE-MRI
Authors: Kocanaogullari Aziz , Ariyurek Cemre , Afacan Onur , Kurugol Sila
Published: August 2023

Radial DCE-MRI is robust to motion. However, bulk motion or heavy breathing causes 1) irrecoverably deteriorated k-space lines acquired during motion events reducing image quality, 2) misaligned volumes in a dynamic sequence. In this work we propose to solve the first problem by fitting a Gaussian process to the k-space center of each spoke over time and using it to determine outlier spokes corrupted by motion. We solve the second problem by clustering the dynamic data to respective motionless phases before and after each motion event and registering volumes between phases for computationally efficient correction of motion with fewer registrations.
Mapping human brain development at new spatial resolutions using deep learning and high-resolution quantitative MRI
Authors: Doumou Georgia , Lin Hongxiang , Lorio Sara , Vaculčiaková Lenka , Pine Kerrin J. , Weiskopf Nikolaus , O'Muircheartaigh Jonathan , Alexander Daniel C. , Carmichael David W.
Published: August 2023

High-resolution quantitative MRI using ultra-high field scanners (7T) could advance a range of research and clinical applications if limitations, both practical (e.g. long acquisitions) and technical (e.g. B1 non-uniformity), can be avoided. This could be achieved by using 7T information to enhance conventional field strength images. To test this approach, paired 3T-7T R1 maps were used to train a U-Net variant to enhance 3T R1 maps. Leave-one-out cross-validation, quantitative evaluation, as well as external validation on an external clinical dataset, demonstrated promising enhancement with visual and quantitative metrics more similar to 7T R1 maps than the 3T equivalents.
Quantitative MRI to characterize diffusion-controlled release of gadolinium from a calcium sulphate matrix
Authors: Hong Greg , Khazaee Tina , Cobos Santiago , Christiansen Spencer , Liu Junmin , Drangova Maria , Holdsworth David
Published: August 2023

Calcium sulfate (CS) is commonly used to deliver antibiotics to treat periprosthetic joint infection, which is a leading cause of early revision. There is an unmet need for non-invasive measurement of antibiotic release from CS, which would improve understanding of antibiotic delivery in-vivo. Through the use of a gadolinium-based contrast agent as a surrogate, this study shows that quantitative MRI (R2* and QSM) can be used to track diffusion-controlled release. We demonstrate this in a phantom study consisting of a cylindrical CS core surrounded by agar, where gadolinium diffuses out of the core and through the agar sample.
Microstructure Imaging of Head and Neck Cancers using an Oscillating Diffusion Gradient Sequence and a Random Walk with Barriers Model
Authors: Nejad-Davarani Siamak , Mierzwa Michelle , Feiweier Thorsten , Casper Keith , Cao Yue
Published: August 2023

In vivo microstructure imaging based on diffusion weighted imaging can provide valuable information on tumor characteristics and response to cancer therapy. An oscillating diffusion gradient spin-echo sequence was used to acquire DW images with short diffusion times, along with those acquired by a pulsed diffusion gradient spin-echo sequence. Using a random walk with barriers model, microstructure/diffusion parameters in primary and nodal head and neck tumors were estimated prior to, and after two weeks of cancer treatment. Results show feasibility of this method to detect significant changes in these parameters, across the two imaging time points.
dtiRIM: A recurrent inference machine for diffusion tensor estimation
Authors: Sabidussi Emanoel R. , Klein Stefan , Jeurissen Ben , Poot Dirk
Published: August 2023

In Diffusion MRI, the large variability of acquisition schemes limits broader use of Deep Learning for parameter estimation, with data-specific models needed for high-quality predictions. To reduce dependency on training data, we present dtiRIM, a recurrent neural network that learns a regularized solution to a model-based inverse problem. Using the diffusion model allows independent parameters (e.g. gradient directions) to also influence the estimation. We show that a single dtiRIM model predicts diffusion parameters for multiple datasets with lower error than the current state-of-the-art. Our study suggests that dtiRIM has the potential to be the first general learning method for DTI.
A CNN for Oxygen Extraction Fraction Mapping with combined QSM and qBOLD
Authors: Kinz Patrick , Schad Lothar
Published: August 2023

MRI-based mapping of oxygen extraction fraction with QSM and qBOLD is a non-invasive diagnostic tool with many possible applications. But current reconstruction methods based on quasi-Newton (QN) methods are very dependent on accurate parameter initialization. Artificial Neural Networks showed a lot of potential in our previous works. Using a Convolutional Neural Network improves the reconstruction, since neighboring voxels can provide additional information. Using a GESFIDE sequence to sample the qBOLD signal instead of a standard mGRE that samples only the FID, improves the reconstruction accuracy of R2, Y and χnb a lot.
A Novel Manganese EOB-Pyclen Diacetate Chelate for Liver-Specific MRI
Authors: Hall Ryan , Qin Jing-Can , Laney Victoria , Ayat Nadia
Published: August 2023

MRI is increasingly utilized for the diagnosis of liver disease and focal liver lesions. While liver-targeted gadolinium-based contrast agents (GBCAs) have high efficacy, they are shadowed by safety concerns regarding tissue retention. We have developed a liver-targeted manganese alternative – Mn-EOB-PC2A – that uses a liver-targeted ethoxybenzyl modified macrocyclic pyclen diacetate platform. Relaxivity measurements for Mn-EOB-PC2A suggest comparable performance to the GBCA alternatives, and in vitro characterization suggests strong uptake in hepatocytes with minimal toxicity. MRI with Mn-EOB-PC2A demonstrated strong liver-specific enhancement at a clinically relevant dose, underscoring the potential for Mn-EOB-PC2A as an alternative to traditional liver-targeted Gd-based platforms.
Detection of low-boiling point perfluorocarbon nanodroplets using hyperCEST: a path toward a dual-modality dual-phase contrast agent
Authors: McHugh Christian , Durham Phillip , Kelley Michele , Bryden Nicholas , Dayton Paul , Branca Rosa
Published: August 2023

Recently, it was shown that hyperCEST enables detection of microbubbles at clinically relevant ultrasound doses. Nanodroplets filled with low-boiling point perfluorocarbons are precursors of microbubbles. Because the chemical shift of xenon in liquid-phase perfluorocarbon nanodroplets is different than that in gas-phase microbubbles, hyperCEST detection of these nanodroplets could enable MR detection of their phase-change upon ultrasound activation. To this end, here we investigate if perfluorocarbon nanodroplets can be used as hyperCEST agent, first in vitro and then in vivo.
Integrative assessment of the aquaporin-4 role to a glucose stimulus by magnetic resonance
Authors: Yagüe Balbino , Guadilla Irene , Cerdán Sebastián , Lizarbe Blanca , López Pilar
Published: August 2023

Aquaporin-4 (AQP4) is a transmembrane water channel highly expressed in central nervous system, regulating fluid exchange by water transport between two sides of plasmatic membrane, and depending on concentration gradients of solutes, like glucose. On these grounds, we studied AQP4’s role in glucose uptake. AQP4 inhibitor TGN-020 was administrated in adult mice before vehicle and glucose stimulus. Diffusion and T2* images were acquired and apparent diffusion coefficient and T2* were measured. Ex vivo 1H high-resolution magic angle spinning spectra were acquired. Results showed that TGN avoid physiological cerebral response linked to glucose uptake, noting the AQP4 involvement in the process.
Altered brain pulsations in phychosis.
Authors: Hiukka Emma , Helalari Heta , Korhonen Vesa , Kiviniemi Vesa
Published: August 2023

The detection of functional alterations in psychotic subjects has proven to be a demanding task. In this study we used ultrafast fMRI to investigate physiological brain pulsations driving blood and CSF convection in psychotic brain. We detected dichotomized changes in opposing brain region pulsations between the upper frontal and lower posterior parts of the brain in all three major brain pulsations. The altered brain pulsations in psychotic brains may be connected to abnormal convection of metabolites via CSF and blood providing an physiological basis for the altered reality experiences in psychosis.
Ketamine Induced Glutamate Alternations in Treatment-Resistant Depression. A 1H-MRS randomised placebo controlled study.
Authors: Sitnikov Rouslan , Tiger Mikael , Lundberg Johan
Published: August 2023

Background: The glutamate N-methyl-D-aspartate receptor antagonist ketamine has a rapid antidepressant effect in major depressive disorder (MDD) patients. Though, the ketamine's possible mechanism of action has been debated the main hypothesis was focused around glutamate.

Methods: A proton short-echo MR Spectroscopy was utilised to examined three brain regions Anterior Cingulate Cortex, Hippocampus and Raphe nuclei before and 24-hours after treatment. 28 Selective Serotonin Reuptake Inhibitor resistant MDD patients were randomized to double blind monotherapy with 0.5 mg/kg ketamine or placebo infusion.

Results: glutamate correlates with depression symptoms severity in ACC and HC in opposing ways in ketamine group.
Acceleration of chemical shift encoding-based water-fat imaging for pancreatic proton density fat fraction mapping in a single breath-hold
Authors: Rupp Selina , Wu Mingming , Han Jessie , Weiss Kilian , Peeters Johannes , Holzapfel Christina , Makowski Marcus , Junker Daniela , Karampinos Dimitrios
Published: August 2023

With rising prevalence of obesity and metabolic syndrome comes an increasing demand of noninvasive detection of nonalcoholic fatty pancreas disease. Chemical shift encoding-based water-fat separation based on a multi-echo gradient echo acquisition enables pancreatic fat fraction (PDFF) mapping. The pancreas is a small organ and requires high spatial resolution which results in prolonged breath-hold duration for PDFF mapping. The present work aims to accelerate high-resolution single-breath-hold pancreas PDFF mapping using a methodology combining sparse sampled acquisitions with compressed sensing and deep learning reconstructions.
3D MR spirometry sensitivity to gravity lung dependence in healthy volunteers
Authors: Barrau Nathalie , Barakat Claire Pellot , He Zhongzheng , Emre Tolga , Nemeth Angéline , Afkir Anass , Cai Wenpei , Brulon Vincent , Boucneau Tanguy , Fernandez Brice , Besson Florent , Lebon Vincent , Maître Xavier
Published: August 2023

Spirometry is a standard exam in pulmonary function testing for assessing the efficiency of global ventilation from flow-volume loops measured at the mouth during forced respiratory cycles. A newly developed technique, 3D MR spirometry, makes use of dynamic magnetic resonance imaging during spontaneous breathing to produce regional characterization of the lung function. The sensitivity of the technique was challenged with respect to gravity by extracting the associated ventilation gradients in prone and supine healthy volunteers.
Local Integral EPT - the alter ego of Helmholtz EPT
Authors: Zilberti Luca , Arduino Alessandro , Zanovello Umberto , Bottauscio Oriano
Published: August 2023

A local-integral solution of the Electric Properties Tomography (EPT) problem is proposed. The method exploits a trick to consider the Helmholtz equation that regulates EPT as a Poisson equation. Then, it inverts the equation under the local homogeneity assumption, using Green's theorem. The approach turns out to be equivalent to the traditional Helmholtz-EPT.
MRI-based radiomics quantification for characterization of clear cell renal cell carcinoma.
Authors: Bane Octavia , Kyriakakos Christopher , Gillingham Nicolas , Cuevas Jordan , Meilika Kirolos , Daza Jorge , Horowitz Amir , Taouli Bachir , Badani Ketan , Lewis Sara
Published: August 2023

In this prospective, single-center study, we evaluated the use of qualitative features and quantitative radiomics features from MRI for diagnosis and characterization of clear cell renal cell carcinoma (ccRCC). Qualitative features in isolation were of no value for diagnosing ccRCC, while the ccRCC likelihood score, which takes into account qualitative T2w signal and contrast enhancement pattern, had comparable diagnostic performance to the quantitative radiomics features. Quantitative radiomics features had good to excellent diagnostic performance in identifying ccRCC, as well as correlated to grade of ccRCC.
Repeatability of APTw imaging at 7T
Authors: Obdeijn Iris , Alic Lejla , Lequin Maarten , Plasschaert Sabine , van der Kemp Wybe , Hoogduin Hans , Klomp Dennis , Wijnen Jannie , Wiegers Evita
Published: August 2023

APTw imaging is a potential imaging biomarker to assess treatment effects in brain tumours, especially at high field MRI (7T) due to improved signal-to-noise-ratio enabling the assessment of APTw values in heterogenous tumours. Embedding of APTw imaging in clinical decision making requires insight in the repeatability of APTw imaging. Therefore, we evaluated the repeatability of APTw imaging at 7T by using a phantom and in vivo in the human brain subjects. Repeatable and specific APTw maps were obtained at 7T, which facilitate the potential of detecting metabolic changes in brain tumours due to treatment.
Robust Lorentzian fitting of CEST spectra utilizing joint spatial regularization
Authors: Maier Oliver , Fabian Moritz , Mennecke Angelika , Schmidt Manuel , Dörfler Arnd , Bredies Kristian , Zaiss Moritz , Stollberger Rudolf
Published: August 2023

Chemical Exchange Saturation Transfer (CEST) enables characterization of tissue in vivo by measuring a z-spectrum. Quantitative separation of individual contributions to this spectrum is performed by fitting several Lorentzian shaped lines to the acquired data. Current implementations of the fitting procedure suffer from poor SNR and ambiguity of peaks lying close to each other. To this end, we propose to include a joint spatial regularization to the fitting process to counter the poor SNR and thus improve separation of individual peaks in the final reconstruction.
CEST effects change with age
Authors: Mennecke Angelika , Khakzar Katrin , German Alexander , Herz Kai , Fabian Moritz , Liebert Andrzej , Nagel Armin , Laun Frederik , Schmidt Manuel , Winkler Jürgen , Dörfler Arnd , Zaiss Moritz
Published: August 2023

The amide and rNOE CEST amplitudes are negatively correlated with age. Most prominently, the mean gray matter amide CEST amplitude decreases on average by 0.22 % per year of age in the cohort of our study.
Quantitative 3D Mapping of Cr and PCr Concentrations at 3T using Snapshot AREX CEST MRI
Authors: Perlman Or , Coll-Font Jaume , Herz Kai , Zaiss Moritz , Nguyen Christopher , Farrar Christian
Published: August 2023

The dynamics of creatine and phosphocreatine distributions provide an important means for assessing metabolic function. While CEST-weighted MRI allows for the imaging of metabolite alterations, it is affected by semisolid-MT, spillover, and T1 contributions, and is typically analyzed on a two-dimensional image, given the inherently long acquisition times. Here, we performed 3D quantitative mapping of Cr and PCr concentrations in the human calf muscle at 3T, using a rapid snapshot-CEST protocol followed by apparent exchange-dependent relaxation (AREX) analysis. Significant (p<0.001) changes in the concentrations of both creatine and phosphocreatine were measured during exercise, in agreement with the literature.
Development of CEST MRI for the characterization of Alzheimer’s Disease
Authors: Yu Fang , Bell Natalie , Davenport Elizabeth , Bowen Spencer , Kelley Brendan , Dimitrov Ivan , Keupp Jochen , Vinogradov Elena
Published: August 2023

Alzheimer’s Disease (AD) is the leading cause of dementia, afflicting over 5 million Americans and 45 million people worldwide. We are developing CEST protocol for the characterization of abnormal protein accumulation and pathological molecular changes in AD. Our results indicate increased CEST in all frequency ranges, with the maximum around 2ppm. While preliminary, this data demonstrates CEST MRI is capable of clear differentiation between patients with AD and healthy individuals.
Comparison of Nova 1Tx vs 8Tx head coils for routine 7T neuroimaging
Authors: Ding Belinda , Rua Catarina , Rodgers Christopher
Published: August 2023

Most 7T MRI sites have two head coils available for neuroimaging: a single-transmit coil and one capable of parallel transmission (pTx, or 8Tx). The 8Tx coil has a circularly polarised (CP) mode, allowing it to play RF waveforms identical to its 1Tx counterpart. This study compares the performance of a 1Tx coil against an 8Tx coil from the same manufacturer for routine neuroimaging. The 8Tx coil gave better B1+ profiles in posterior brain regions which translates into improvements in other imaging sequences. It also enables the inclusion of pTx-enabled sequences. However, more detailed studies are needed before pooling data.
Model validation of a 500 MHz Inductive Resonator for 11.7 T Brain MRI
Authors: Gudino Natalia , de Zwart Jacco , Van Gelderen Peter , Dodd Stephen , Duyn Jeff , Murphy-Boesch Joe
Published: August 2023

To evaluate safety of a 500 MHz inductive birdcage resonator for human brain MRI at 11.7 T, we compared phantom SAR measurements with predictions based on simulations. On a head-shaped phantom with realistic permittivity and conductivity, good correspondence was achieved in heating distributions when irradiating the phantom with 85 W RF power. The ability to predict SAR at 500MHz with simulation is critical step towards in-vivo MRI at 11.7 T.
Comparison of ultra-high field MRI of ancient remains at 9.4T and 3T
Authors: Tesfai Agazi , Fischer Johannes , Özen Ali , Bär Sébastien , Eppenberger Patrick , Öhrström Lena , Rühli Frank , Ludwig Ute , Bock Michael
Published: August 2023

Ancient mummified samples have ultra-short T2* which decreases with increasing field strength. Here, image quality and T2* relaxation times are compared for different tissues of a mummified hand between a clinical 3T and a preclinical 9.4T system using a 3D UTE sequence. Although T2* is shorter at 9.4T, image quality was superior to 3T, justifying the benefits of ultra-high fields (UHF).
MP-PCA denoising of complex imaging data for direct visualization of the dentatorubrothalamic tract using diffusion MRI at 3T
Authors: Ades-Aron Benjamin , Coelho Santiago , Lemberskiy Gregory , Mogilner Alon , Novikov Dmitry , Shepherd Timothy , Fieremans Els
Published: August 2023

Direct visualization of anisotropic structures in the brainstem, basal ganglia and thalamus could improve functional neurosurgery planning and characterize changes associated with pathology, treatment response or side effects. Postmortem MRI microscopy demonstrates the potential for high resolution diffusion MRI to detect such functional organization. However, in vivo signal-to-noise limitations have precluded accurate quantitative diffusion measurements at sufficient spatial resolution for these structures. We demonstrate that MP-PCA denoising of complex dMRI at 1-mm isotropic resolution and b-values up to 2000 s/mm2 enables direct visualization of the dentatorubrothalamic tract, the key white matter pathway for functional neurosurgical treatment of tremor.
Improved digit selectivity using VASO-CBV in 7T digit motor mapping
Authors: Oliveira Icaro , Siero Jeroen , Dumoulin Serge , Zwaag Wietske
Published: August 2023

We used sub-millimeter resolution VASO fMRI at 7T to simultaneously map CBV-VASO and BOLD activation in the sensorimotor and somatosensory cortex during a finger digit mapping task. We reliably showed digit representation maps and quantified digit selectivity for both VASO-CBV and BOLD activations. VASO-CBV demonstrated a higher digit selectivity, confirming the higher spatial specificity of VASO-CBV.
Combining the benefits of 3D acquisitions and spiral readouts in VASO fMRI
Authors: Monreal Alejandro , Ma Ruoyun , Huber Renzo , Kurban Denizhan , Boulant Nicolas , Poser Benedikt
Published: August 2023

VASO fMRI can provide beneficial localization specificity and quantifiability compared to the commonly used BOLD contrast. Previous work has also shown the benefits of using spiral readouts compared to Cartesian.

In this work, we explore the benefits of 3D stack of spirals readouts and compare it with the current state of the art 3D EPI readouts for VASO fMRI. The sequence implementation is done using Pulseq, images were reconstructed using gpuNUFFT; functional analysis with an openly available pipeline. We find that a tSNR efficiency improvement of a factor of 2.5 over EPI is achieved using the proposed spiral implementation.
Detection of fast responses in diffusion fMRI of the human visual cortex through reduced vascular contamination
Authors: Hodono Shota , Polimeni Jonathan , Cloos Martijn
Published: August 2023

A key feature of the diffusion-weighted fMRI (DfMRI) response is that it can detect activation with an earlier onset compared to the hemodynamic response measured with spin-echo Blood Oxygenation Level Dependent (SE-BOLD), which was taken as evidence that the DfMRI signal can track an aspect of neural activation that is distinct from hemodynamics. However, despite considerable efforts, it has been challenging to detect this early onset reliably. Here we revisit this question leveraging modern fMRI hardware and acquisition approaches to reduce unwanted hemodynamic contributions. Averaged across all subjects, we see a 1.6±0.2s earlier onset compared to SE-BOLD.
Understanding the effect of noise on cognition using attention framework Navon task
Authors: Kumaran S Senthil , Singh Himanshu , Ankeeta A
Published: August 2023

Cognitive studies using functional imaging are inherently associated with nonstimulant noise in MRI. Dissociating the noise aspect in functional imaging from cognitive traits is crucial in delineating auditory cognition. This study explores the association of noise in auditory cognition studies. we designed a functional Navon task paradigm with introduction of pink noise characteristics modelled as part of its memory phase. Variation of noise induced the cognitive masking associated with characteristics of stimuli across the local and global suppression.
The role of Cerebellum in a visuomotor task: A Dynamic Causal Modeling approach
Authors: Lorenzi Roberta , Alahmadi Adnan , Casiraghi Letizia , Monteverdi Anita , D'Angelo Egidio , Palesi Fulvia , Wheeler-Kingshott Claudia Gandini
Published: August 2023

Dynamic Causal Modelling(DCM) is a framework enabling the quantification of the causal relationship between functionally connected brain regions. Here we included the cerebellum in a visuomotor network to investigate its role in motion prediction and how different Grip-Force levels modulate the effective connectivity between cerebellum and primary visual cortex. We estimated different DCMs models and we used Bayesian Models Selection to assess the best model at group-level. This study paves the way for investigating the source of BOLD non-linearities when applying different grip-forces in terms of modulations of the cerebro-cerebellar connections.
Proof of concept of volumetric MR-temperature monitoring during microwave ablation of liver tumor in a patient
Authors: Bour Pierre , Faller Thibaut , Ozenne Valery , Quesson Bruno , Seidensticker Max , Dietrich Olaf
Published: August 2023

Microwave tumor ablation in the liver is commonly performed in computed tomography scanners with limited imaging capability for real-time monitoring of treatment progression. Performing this procedure under MRI enables to monitor temperature and thermal dose during the ablation. It allows better understanding of the lesion creation and gives better insight of the treatment outcome. In this study, we evaluate a complete MR-guided workflow that include volumetric temperature and dose monitoring during ablation using an ultrafast EPI sequence with respiratory triggering. Results show that spatial extent of the lesion can be monitored and displayed in real-time.
Effect of a lifestyle intervention with plant-based diet on liver and muscle lipids in metabolic syndrome-associated osteoarthritis patients
Authors: de Jonge C.S. , Wagenaar C.A. , Walrabenstein W. , Troelstra M.A. , Nederveen A.J. , van Schaardenburg D.
Published: August 2023

The aim of this study was to evaluate the effect of a 16-week multidisciplinary lifestyle intervention with a plant-based diet on hepatocellular, intra- and extramyocellular lipid levels in patients with metabolic syndrome-associated osteoarthritis as measured by proton MR spectroscopy. The intervention group (n=17) was compared with the control group receiving usual care (n=15). At the end of the intervention the intervention group showed reduced hepatocellular lipid levels and total body fat mass and improved metabolic and inflammatory markers compared to the control group. There was no observable change of intra- and extramyocellular lipid levels.
Real-time quality assurance for volumetric motion estimation during MR-guided radiotherapy
Authors: Huttinga Niek , Bruijnen Tom , van den Berg Cornelis , Sbrizzi Alessandro
Published: August 2023

Respiratory motion during radiotherapy decreases the time-efficiency of treatments. The MR-Linac can potentially improve this with real-time 3D MR-based motion estimates. Ideally, these estimates should be accompanied with estimation uncertainty to ensure patient safety and spare organs-at-risk during bulk motion or breathing pattern change, but this is typically not provided by state-of-the-art methods. In this work we extend a previously proposed probabilistic framework for real-time motion and uncertainty estimation with a rejection criterion based on the estimation uncertainty. Results show that the proposed rejection criterion preserves low end-point-errors and rejects erroneous motion estimates during bulk motion and breathing pattern changes.
Staging Lymphedema with Dual Agent Relaxivity Contrast Magnetic Resonance Imaging (DARC-MRL)
Authors: Sibley Robert , Loening Andreas
Published: August 2023

This retrospective cross-sectional study assessed different methods for staging lymphedema on Dual Agent Relaxivity Contrast MR Lymphangiography (DARC-MRL). Images from 20 patients (40 limbs) with clinically diagnosed and staged lower extremity lymphedema who had undergone DARC-MRL were assessed for dermal backflow, lymphatic vessel enhancement, and subcutaneous edema, in six regions of the lower limbs. These assessments were translated into a dermal backflow score and an edema score of our own design, as well as a recently published MRL Stage (Soga et al. 2021). All three scores demonstrated strong to excellent correlation with International Society of Lymphology (ISL) clinical stages.
Development of an Efficient MRE/MRI Protocol for Multiparametric Assessment of Liver, Spleen, and Kidneys to Diagnose Hepatorenal Syndrome
Authors: Owusu Nana , Zhu Zheng , Li Jiahui , Glaser Kevin , Sui Yi , Simonetto Douglas , Kamath Patrick , Shah Vijay , Venkatesh Sudhakar , Ehman Richard , Yin Meng
Published: August 2023

An efficient imaging protocol was developed to facilitate diagnosis of hepatorenal syndrome in patients with decompensated cirrhosis. Multiparametric MRI for quantifying perfusion, diffusion, and blood oxygenation, as well as multiparametric MRE for quantifying viscoelasticity and tissue pressure were optimized in preparation for the pilot study predicting hepatorenal syndrome. Results demonstrate the feasibility of the multiparametric protocol and provide motivation for commencing clinical testing.
Interactive Real-Time MRI-Guided Needle Tracking using Scanner Remote Control
Authors: Aleong Amanda , Tokuda Junichi , Moreira Pedro , Seethamraju Ravi , Moran Gerald , Bhat Himanshu , Weersink Robert
Published: August 2023

MRI offers the gold standard for delineating cancerous lesions in soft tissue. Minimally invasive needle-based interventions require the accurate placement of multiple long, flexible needles at the target site. The manual tracking of needles in MR images is a time-consuming task that is further challenged by needle deflection. Automated needle segmentation offers the means to evaluate the alignment of the needle to the scan plane. This work demonstrates automatic needle tracking using remote scan control to dynamically update the scan plane of a real-time MR sequence. Automatic scan plane alignment is validated, and the feasibility of needle tracking is assessed.
Establishing a passive motor fMRI protocol for intraoperative 3T MRI: Preliminary results
Authors: Hangel Gilbert , Wais Jonathan , Tomschik Matthias , Mayr-Geisl Gudrun , Pruckner Philip , Cardoso Pedro , Dorfer Christian , Kasprian Gregor , Rössler Karl
Published: August 2023

Using a 3T ioMRI system with an 8-channel intraoperative coil, we developed passive sensorimotor intraoperative fMRI protocol under anaesthesia at our site. We successfully applied it to passive fMRI of hand and foot in an exploratory cohort of four patients, confirming correspondence of activation to preoperative fMRI scans. This is the first reported implementation of intraoperative 3T passive fMRI.
Acquiring and Reconstructing UTE-Dixon Fat and Water Images for Generation of Synthetic CT in Thorax on an MR-Linac
Authors: Goodburn Rosie , Bano Wajiha , Oelfke Uwe , Wetscherek Andreas
Published: August 2023

Generation of synthetic CT (synCT) for adaptive MR-guided radiotherapy is particularly challenging in the thorax due to the impact of respiratory motion, short-T2* tissues in lung, and a complex tissue-density structure. To address these challenges and provide data suitable for generating thoracic synCTs, we developed a UTE-Dixon sequence with a golden-angle stack-of-stars trajectory. We have demonstrated successful online acquisition and offline reconstruction of UTE, fat, water and B0 images as well as retrospective respiratory gating. Work is ongoing to optimize processing of respiratory-resolution of UTE and Dixon images that will form the input to synCT in thorax on an MR-Linac.
Estimating acoustic intensity in viscoelastic media using MR acoustic radiation force imaging and multifrequency MR elastography
Authors: Li Ningrui , Gaur Pooja , Quah Kristin , Pauly Kim Butts
Published: August 2023

In addition to focal spot localization for non-ablative transcranial ultrasound therapies, MR acoustic radiation force imaging (MR-ARFI) has the potential to estimate the acoustic intensity delivered to the target. However, variability in tissue stiffness and viscosity precludes accurate estimates of acoustic intensity from MR-ARFI displacements alone. We demonstrate that multifrequency MRE can be used to characterize a medium’s viscoelastic response to focused ultrasound, improving estimates of acoustic intensity and enabling safer, more effective treatments.
AI-Assisted Analysis of Iceball Coverage on Patient Outcomes Following MR-guided Focal Cryoablation for Prostate Cancer: A Retrospective Study
Authors: Fordham Nicholas , Tokuda Junichi , Moreira Pedro , Tempany Clare , Tuncali Kemal
Published: August 2023

We conducted a retrospective study of 44 MRI-guided focal cryoablation cases for prostate cancer. Our goal was to evaluate AI-assisted MRI-based assessment of inadvertent cryoinjuries in the surrounding structures as predictors of post-procedural morbidities. Specifically, we estimated the iceball involvement with the external urethral sphincter (EUS) and the neurovascular bundle (NVB) using intraprocedural T2-weighted MRI and correlated with acute postoperative urinary incontinence and erectile dysfunction. The study demonstrated a correlation between incontinence and MRI-estimated iceball involvement with the EUS. However, no correlation was found between erectile dysfunction and the iceball involvement with the NVB.