A5010688760- Advanced MRI Techniques and Applications
- MRI in cancer diagnosis
- Cardiac Imaging and Diagnostics
- Renal and Vascular Pathologies
- Fetal and Pediatric Neurological Disorders
- Cardiovascular Function and Risk Factors
- Atomic and Subatomic Physics Research
- Liver Disease and Transplantation
- Seismic Imaging and Inversion Techniques
- Brain Tumor Detection and Classification
- Transplantation: Methods and Outcomes
- Machine Learning and ELM
- Medical Image Segmentation Techniques
- Ultrasound and Hyperthermia Applications
- Electron Spin Resonance Studies
- Radiomics and Machine Learning in Medical Imaging
- Medical Imaging and Analysis
- Glioma Diagnosis and Treatment
- Lanthanide and Transition Metal Complexes
- Photoacoustic and Ultrasonic Imaging
Navarre Institute of Health Research
2020-2025
Clinica Universidad de Navarra
2020-2024
Universidad Publica de Navarra
2016
Vicomtech
2016
Purpose To evaluate labeling efficiency of pseudo‐continuous arterial spin (PCASL) and to find the gradient parameters that increase PCASL robustness for renal perfusion measurements. Methods Aortic blood flow was characterized in 3 groups: young healthy volunteers (YHV1), chronic kidney disease (CKD) patients (CKDP), controls (HCO). inversion evaluated through numeric simulations considering measured pulsatile velocity profiles off‐resonance effects a wide range parameters, results were...
Background Arterial spin labeling (ASL) allows non‐invasive quantification of myocardial blood flow (MBF). Double‐ECG gating (DG) ASL is more robust to heart rate variability than single‐ECG (SG), but its reproducibility requires further investigation. Moreover, the existence multiple models hinders application. Frequency‐offset‐corrected‐inversion (FOCI) pulses provide sharper edge profiles hyperbolic‐secant (HS), which could benefit ASL. Purpose To assess performance MBF for DG compared SG...
Background Multiparametric MRI provides assessment of functional and structural parameters in kidney allografts. It offers a non‐invasive alternative to the current reference standard biopsy. Purpose To evaluate diagnostic prognostic utility allograft function first 3‐months post‐transplantation. Study Type Prospective. Subjects 32 transplant recipients (54 ± 17 years, 20 females), divided into two groups according estimated glomerular filtration rate (eGFR) at post‐transplantation: inferior...
Background Myocardial perfusion is evaluated in first‐pass MRI using a gadolinium‐based contrast agent, which limits its repeatability and restricts use patients with abnormal kidney function. Arterial spin labeling (ASL) promising technique for measuring myocardial without injection. The ratio of stress to rest perfusion, termed reserve (MPR), an indicator the severity stenosis coronary artery disease (CAD). Purpose To quantify increases pharmacological vasodilation, explore MPR differences...
Monitoring renal allograft function after transplantation is key for the early detection of impairment, which in turn can contribute to preventing loss allograft. Multiparametric MRI (mpMRI) a promising noninvasive technique assess and characterize physiopathology; however, few studies have employed mpMRI allografts with stable (maintained over long time period). The purposes current study were evaluate reproducibility transplant patients normal values measured parameters, estimate labeling...
Background In patients with suspected coronary artery disease (CAD), myocardial perfusion is assessed under rest and pharmacological stress to identify ischemia. Splenic switch‐off, defined as the splenic attenuation in response adenosine, has been proposed an indicator of adequacy. Its occurrence previously first‐pass images, but use noncontrast techniques would be highly beneficial. Purpose To explore ability pseudo‐continuous arterial spin labeling (PCASL) switch‐off CAD. Study Type...
A pseudocontinuous arterial spin labeling (PCASL) sequence combined with background suppression and single-shot accelerated 3D RARE stack-of-spirals was used to evaluate cerebrovascular reactivity (CVR) induced by breath-holding (BH) in ten healthy volunteers. Four different models designed using the measured change PETCO2 BH were compared, for CVR quantification. The objective of this comparison understand which regressor offered a better physiological model characterize cerebral blood flow...
To evaluate the accuracy and reproducibility of myocardial blood flow measurements obtained under different breathing strategies motion correction techniques with arterial spin labeling.A prospective cardiac labeling study was performed in 12 volunteers at 3 Tesla. Perfusion images were acquired twice breath-hold, synchronized-breathing, free-breathing. Motion detection based on temporal intensity variation a voxel, as well image registration pairwise groupwise approaches, applied evaluated...
Splenic switch-off, defined as the stress to rest splenic blood flow (SBF) attenuation in response adenosine, is an indicator of adequacy. This study aims explore ability pseudo-continuous arterial spin labeling (PCASL) identify switch-off patients with suspected CAD. In healthy subjects, multi-delay PCASL data were acquired quantify SBF and determine adequate postlabeling delay. patients, single-delay first-pass perfusion images under adenosine conditions. could demonstrate feasibility during MRI.
A multiparametric MRI protocol (perfusion, diffusion and T1) was employed to assess longitudinally the kidney allograft at different time points after transplatation (first week, 3rd month one year surgery) in a 3T system. Patients were divided into stable unstable function according their evolution. Results showed that GFR RBF increased for patients with decreased function, showing significant differences between groups Exam 3. In conclusion, can help has potential predict dysfunction when...
This multicentre study aimed at assessing multi-vendor accuracy and reproducibility of typical MR biomarkers on 3T 1.5T scanners from 5 clinical centers. MRI acquisitions were performed using NIST protocols, Essential System Diffusion phantoms. T1 was measured by 3-parameter fitting, while T2 ADC mono-exponential PhantomViewer software. When compared with reference values, non-negligible discrepancies found across vendors, especially for measurements. Reproducibility vendor-dependent, higher...
Renal perfusion quantification is of importance in the post-operative surveillance allograft translated patients. Together with cortical measurement, there a strong interest medullary values, which requires an additional segmentation step renal compartments. We applied Gaussian Mixture Models over MRI dataset to automatically extract labels for each compartment separately calculate and values. Proposed method showed performance metrics above 85% against ground truth correlation coefficient...
PCASL was used to measure cerebral blood flow (CBF) in eighteen patients with high-grade gliomas (III and IV) during normal breathing followed by a breath-holding task (ten periods of 21s interleaved breathing) assess baseline CBF cerebrovascular reactivity (CVR). All completed the successfully CVR maps were generated. ratio contrast-enhanced tumor area higher grade IV than III gliomas, as expected. areas decreased compared GM values. More studies are needed heterogeneity tumoral tissue.
Motivation: Pseudo-continuous Arterial Spin Labeling (PCASL) MRI is a promising technique for assessing renal perfusion. Previous studies have been carried out at 1.5T and 3T field strengths, but comparison of data acquired both strengths has never performed. Goal(s): The aim this work was to assess the effects strength on measured perfusion signal evaluate reproducibility PCASL fieldsApproach: Healthy volunteers underwent repeated scans scanners, spaced week apart. Results: results showed...
Accurate segmentation of renal tissues is an essential step for perfusion estimation and postoperative assessment the allograft. Images are usually manually labeled, which tedious prone to human error. We present image analysis method automatic based on magnetic resonance imaging. Specifically, non-contrasted pseudo-continuous arterial spin labeling (PCASL) images used kidney transplant evaluation estimation, as a biomarker status The proposed uses machine/deep learning tools classification...
In this study, we investigated the influence of ECG-triggering and respiration strategy choice on renal perfusion. To end, pCASL data healthy volunteers was acquired at 3T. Acquisitions processing followed PARENCHIMA consensus. Processing consisted groupwise registration, manual whole kidney segmentation automated cortex/medulla segmentation. All calculated perfusion values were close to expected range for individuals. Preliminary results from four subjects suggest cardiac cycle is...
The spleen plays an important role in diseases related to portal circulation. Pseudo-continuous arterial spin labeling (PCASL) was used assess the Splenic Blood Flow (SBF) using six different post delays five healthy volunteers. SBF and ATT maps were generated by fitting one compartment Buxton kinetic model. This study shows feasibility of single multi-delay PCASL measure blood flow spleen. Obtained values are agreement with previous studies. enables a reliable splenic
Purpose: to evaluate the prognostic potential of a multiparametric renal MRI protocol (perfusion, diffusion and T1) for assessment allograft in very early stages after transplantation. Methods: 18 transplanted patients were imaged 6 days transplantation with ASL, IVIM T1 mapping sequences. 2 groups made depending on evolution (group A: no adverse events group B: any event). Results: eGFR, album-creatinine ratio cortical medullary RBF significantly higher allografts A than B. Significant...
Motion correction methods are a prerequisite in multiple-image registration tasks. We implemented non-rigid groupwise method and ROI-focused for renal pCASL images. evaluated the temporal signal variation cortex after motion using both methods. technique shows statistically significant improvement on tSNR performs better.