Browsing by Author "Munoz, Camila"

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    3D whole-heart grey-blood late gadolinium enhancement cardiovascular magnetic resonance imaging
    (2021) Milotta, Giorgia; Munoz, Camila; Kunze, Karl P.; Neji, Radhouene; Figliozzi, Stefano; Chiribiri, Amedeo; Hajhosseiny, R.; Masci, Pier Giorgio; Prieto Vásquez, Claudia; Botnar, René Michael
    Abstract Purpose To develop a free-breathing whole-heart isotropic-resolution 3D late gadolinium enhancement (LGE) sequence with Dixon-encoding, which provides co-registered 3D grey-blood phase-sensitive inversion-recovery (PSIR) and complementary 3D fat volumes in a single scan of < 7 min. Methods A free-breathing 3D PSIR LGE sequence with dual-echo Dixon readout with a variable density Cartesian trajectory with acceleration factor of 3 is proposed. Image navigators are acquired to correct both inversion recovery (IR)-prepared and reference volumes for 2D translational respiratory motion, enabling motion compensated PSIR reconstruction with 100% respiratory scan efficiency. An intermediate PSIR reconstruction is performed between the in-phase echoes to estimate the signal polarity which is subsequently applied to the IR-prepared water volume to generate a water grey-blood PSIR image. The IR-prepared water volume is obtained using a water/fat separation algorithm from the corresponding dual-echo readout. The complementary fat-volume is obtained after water/fat separation of the reference volume. Ten patients (6 with myocardial scar) were scanned with the proposed water/fat grey-blood 3D PSIR LGE sequence at 1.5 T and compared to breath-held grey-blood 2D LGE sequence in terms of contrast ratio (CR), contrast-to-noise ratio (CNR), scar depiction, scar transmurality, scar mass and image quality. Results Comparable CRs (p = 0.98, 0.40 and 0.83) and CNRs (p = 0.29, 0.40 and 0.26) for blood-myocardium, scar-myocardium and scar-blood respectively were obtained with the proposed free-breathing 3D water/fat LGE and 2D clinical LGE scan. Excellent agreement for scar detection, scar transmurality, scar mass (bias = 0.29%) and image quality scores (from 1: non-diagnostic to 4: excellent) of 3.8 ± 0.42 and 3.6 ± 0.69 (p > 0.99) were obtained with the 2D and 3D PSIR LGE approaches with comparable total acquisition time (p = 0.29). Similar agreement in intra and inter-observer variability were obtained for the 2D and 3D acquisition respectively. Conclusion The proposed approach enabled the acquisition of free-breathing motion-compensated isotropic-resolution 3D grey-blood PSIR LGE and fat volumes. The proposed approach showed good agreement with conventional 2D LGE in terms of CR, scar depiction and scan time, while enabling free-breathing acquisition, whole-heart coverage, reformatting in arbitrary views and visualization of both water and fat information.
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    Clinical comparison of sub-mm high-resolution non-contrast coronary CMR angiography against coronary CT angiography in patients with low-intermediate risk of coronary artery disease: a single center trial
    (2021) Hajhosseiny, R.; Rashid, Imran; Bustin, Aurélien; Munoz, Camila; Cruz, Gastao; Nazir, Muhummad Sohaib; Grigoryan, Karine; Ismail, Tevfk F.; Prieto Vásquez, Claudia; Botnar, René Michael
    Abstract Background The widespread clinical application of coronary cardiovascular magnetic resonance (CMR) angiography (CMRA) for the assessment of coronary artery disease (CAD) remains limited due to low scan efficiency leading to prolonged and unpredictable acquisition times; low spatial-resolution; and residual respiratory motion artefacts resulting in limited image quality. To overcome these limitations, we have integrated highly undersampled acquisitions with image-based navigators and non-rigid motion correction to enable high resolution (sub-1 mm3) free-breathing, contrast-free 3D whole-heart coronary CMRA with 100% respiratory scan efficiency in a clinically feasible and predictable acquisition time. Objectives To evaluate the diagnostic performance of this coronary CMRA framework against coronary computed tomography angiography (CTA) in patients with suspected CAD. Methods Consecutive patients (n = 50) with suspected CAD were examined on a 1.5T CMR scanner. We compared the diagnostic accuracy of coronary CMRA against coronary CTA for detecting a ≥ 50% reduction in luminal diameter. Results The 50 recruited patients (55 ± 9 years, 33 male) completed coronary CMRA in 10.7 ± 1.4 min. Twelve (24%) had significant CAD on coronary CTA. Coronary CMRA obtained diagnostic image quality in 95% of all, 97% of proximal, 97% of middle and 90% of distal coronary segments. The sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy were: per patient (100%, 74%, 55%, 100% and 80%), per vessel (81%, 88%, 46%, 97% and 88%) and per segment (76%, 95%, 44%, 99% and 94%) respectively. Conclusions The high diagnostic image quality and diagnostic performance of coronary CMRA compared against coronary CTA demonstrates the potential of coronary CMRA as a robust and safe non-invasive alternative for excluding significant disease in patients at low-intermediate risk of CAD.
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    Coronary Magnetic Resonance Angiography in Chronic Coronary Syndromes
    (FRONTIERS MEDIA SA, 2021) Hajhosseiny, Reza; Munoz, Camila; Cruz, Gastao; Khamis, Ramzi; Kim, Won Yong; Prieto, Claudia; Botnar, Rene M.
    Cardiovascular disease is the leading cause of mortality worldwide, with atherosclerotic coronary artery disease (CAD) accounting for the majority of cases. X-ray coronary angiography and computed tomography coronary angiography (CCTA) are the imaging modalities of choice for the assessment of CAD. However, the use of ionising radiation and iodinated contrast agents remain drawbacks. There is therefore a clinical need for an alternative modality for the early identification and longitudinal monitoring of CAD without these associated drawbacks. Coronary magnetic resonance angiography (CMRA) could be a potential alternative for the detection and monitoring of coronary arterial stenosis, without exposing patients to ionising radiation or iodinated contrast agents. Further advantages include its versatility, excellent soft tissue characterisation and suitability for repeat imaging. Despite the early promise of CMRA, widespread clinical utilisation remains limited due to long and unpredictable scan times, onerous scan planning, lower spatial resolution, as well as motion related image quality degradation. The past decade has brought about a resurgence in CMRA technology, with significant leaps in image acceleration, respiratory and cardiac motion estimation and advanced motion corrected or motion-resolved image reconstruction. With the advent of artificial intelligence, great advances are also seen in deep learning-based motion estimation, undersampled and super-resolution reconstruction promising further improvements of CMRA. This has enabled high spatial resolution (1 mm isotropic), 3D whole heart CMRA in a clinically feasible and reliable acquisition time of under 10 min. Furthermore, latest super-resolution image reconstruction approaches which are currently under evaluation promise acquisitions as short as 1 min. In this review, we will explore the recent technological advances that are designed to bring CMRA closer to clinical reality.
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    Efficient non-contrast enhanced 3D Cartesian cardiovascular magnetic resonance angiography of the thoracic aorta in 3 min
    (2022) Fotaki, Anastasia; Munoz, Camila; Emanuel, Yaso; Hua, Alina; Bosio, Filippo; Kunze, Karl P.; Neji, Radhouene; Masci, Pier Giorgio; Botnar, Rene M.; Prieto, Claudia
    Background: The application of cardiovascular magnetic resonance angiography (CMRA) for the assessment of thoracic aortic disease is often associated with prolonged and unpredictable acquisition times and residual motion artefacts. To overcome these limitations, we have integrated undersampled acquisition with image-based navigators and inline non-rigid motion correction to enable a free-breathing, contrast-free Cartesian CMRA framework for the visualization of the thoracic aorta in a short and predictable scan of 3 min.
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    Evaluation of accelerated motion-compensated 3d water/fat late gadolinium enhanced MR for atrial wall imaging
    (SPRINGER, 2021) Munoz, Camila; Sim, Iain; Neji, Radhouene; Kunze, Karl P.; Masci, Pier Giorgio; Schmidt, Michaela; O'Neill, Mark; Williams, Steven; Botnar, Rene M.; Prieto, Claudia
    Objective 3D late gadolinium enhancement (LGE) imaging is a promising non-invasive technique for the assessment of atrial fibrosis. However, current techniques result in prolonged and unpredictable scan times and high rates of non-diagnostic images. The purpose of this study was to compare the performance of a recently proposed accelerated respiratory motion-compensated 3D water/fat LGE technique with conventional 3D LGE for atrial wall imaging. Materials and methods 18 patients (age: 55.7 +/- 17.1 years) with atrial fibrillation underwent conventional diaphragmatic navigator gated inversion recovery (IR)-prepared 3D LGE (dNAV) and proposed image-navigator motion-corrected water/fat IR-prepared 3D LGE (iNAV) imaging. Images were assessed for image quality and presence of fibrosis by three expert observers. The scan time for both techniques was recorded. Results Image quality scores were improved with the proposed compared to the conventional method (iNAV: 3.1 +/- 1.0 vs. dNAV: 2.6 +/- 1.0, p = 0.0012, with 1: Non-diagnostic to 4: Full diagnostic). Furthermore, scan time for the proposed method was significantly shorter with a 59% reduction is scan time (4.5 +/- 1.2 min vs. 10.9 +/- 3.9 min, p < 0.0001). The images acquired with the proposed method were deemed as inconclusive less frequently than the conventional images (expert 1/expert 2: 4/7 dNAV and 2/4 iNAV images inconclusive). Discussion The motion-compensated water/fat LGE method enables atrial wall imaging with diagnostic quality comparable to the current conventional approach with a significantly shorter scan of about 5 min.
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    Evaluation of myocarditis with a free-breathing three-dimensional isotropic whole-heart joint T1 and T2 mapping sequence
    (ELSEVIER SCIENCE INC, 2024) Hua, Alina; Velasco, Carlos; Munoz, Camila; Milotta, Giorgia; Fotaki, Anastasia; Bosio, Filippo; Granlund, Inka; Sularz, Agata; Chiribiri, Amedeo; Kunze, Karl P.; Botnar Rene, Michael; Prieto Vásquez, Claudia Del Carmen; Ismail, Tevfik F.
    Background: The diagnosis of myocarditis by cardiovascular magnetic resonance (CMR) requires the use of T2 and T1 weighted imaging, ideally incorporating parametric mapping. Current two-dimensional (2D) mapping sequences are acquired sequentially and involve multiple breath-holds resulting in prolonged scan times and anisotropic image resolution. We developed an isotropic free-breathing three-dimensional (3D) whole-heart sequence that allows simultaneous T1 and T2 mapping and validated it in patients with suspected myocarditis. Methods: Eighteen healthy volunteers and 28 patients with suspected myocarditis underwent conventional 2D T1 and T2 mapping with whole-heart coverage and 3D joint T1/T2 mapping on a 1.5T scanner. Acquisition time, image quality, and diagnostic performance were compared. Qualitative analysis was performed using a 4-point Likert scale. Bland-Altman plots were used to assess the quantitative agreement between 2D and 3D sequences. Results: The 3D T1/T2 sequence was acquired in 8 min 26 s under free breathing, whereas 2D T1 and T2 sequences were acquired with breath-holds in 11 min 44 s (p = 0.0001). All 2D images were diagnostic. For 3D images, 89% (25/ 28) of T1 and 96% (27/28) of T2 images were diagnostic with no significant difference in the proportion of diagnostic images for the 3D and 2D T1 (p = 0.2482) and T2 maps (p = 1.0000). Systematic bias in T1 was noted with biases of 102, 115, and 152 ms for basal-apical segments, with a larger bias for higher T1 values. Good agreement between T2 values for 3D and 2D techniques was found (bias of 1.8, 3.9, and 3.6 ms for basal-apical segments). The sensitivity and specificity of the 3D sequence for diagnosing acute myocarditis were 74% (95% confidence interval [CI] 49%-91%) and 83% (36%-100%), respectively, with a c-statistic (95% CI) of 0.85 (0.79-0.91) and no statistically significant difference between the 2D and 3D sequences for the detection of acute myocarditis for T1 (p = 0.2207) or T2 (p = 1.0000). Conclusion: Free-breathing whole-heart 3D joint T1/T2 mapping was comparable to 2D mapping sequences with respect to diagnostic performance, but with the added advantages of free breathing and shorter scan times. Further work is required to address the bias noted at high T1 values, but this did not significantly impact diagnostic accuracy.
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    Extended MRI-based PET motion correction for cardiac PET/MRI
    (2024) Aizaz, Mueez; Van der Pol, Jochem A. J.; Schneider, Alina; Munoz, Camila; Holtackers, Robert J.; Van Cauteren, Yvonne; Van Langen, Herman; Meeder, Joan G.; Rahel, Braim M.; Wierts, Roel; Botnar, Rene M.; Prieto, Claudia; Moonen, Rik P. M.; Kooi, M. E.
    Purpose: A 2D image navigator (iNAV) based 3D whole-heart sequence has been used to perform MRI and PET non-rigid respiratory motion correction for hybrid PET/MRI. However, only the PET data acquired during the acquisition of the 3D whole-heart MRI is corrected for respiratory motion. This study introduces and evaluates an MRI-based respiratory motion correction method of the complete PET data. Methods Twelve oncology patients scheduled for an additional cardiac 18F-Fluorodeoxyglucose (18F-FDG) PET/MRI and 15 patients with coronary artery disease (CAD) scheduled for cardiac 18F-Choline (18F-FCH) PET/MRI were included. A 2D iNAV recorded the respiratory motion of the myocardium during the 3D whole-heart coronary MR angiography (CMRA) acquisition (~ 10 min). A respiratory belt was used to record the respiratory motion throughout the entire PET/MRI examination (~ 30–90 min). The simultaneously acquired iNAV and respiratory belt signal were used to divide the acquired PET data into 4 bins. The binning was then extended for the complete respiratory belt signal. Data acquired at each bin was reconstructed and combined using iNAV-based motion fields to create a respiratory motion-corrected PET image. Motion-corrected (MC) and non-motion-corrected (NMC) datasets were compared. Gating was also performed to correct cardiac motion. The SUVmax and TBRmax values were calculated for the myocardial wall or a vulnerable coronary plaque for the 18F-FDG and 18F-FCH datasets, respectively. Results A pair-wise comparison showed that the SUVmax and TBRmax values of the motion corrected (MC) datasets were significantly higher than those for the non-motion-corrected (NMC) datasets (8.2 ± 1.0 vs 7.5 ± 1.0, p < 0.01 and 1.9 ± 0.2 vs 1.2 ± 0.2, p < 0.01, respectively). In addition, the SUVmax and TBRmax of the motion corrected and gated (MC_G) reconstructions were also higher than that of the non-motion-corrected but gated (NMC_G) datasets, although for the TBRmax this difference was not statistically significant (9.6 ± 1.3 vs 9.1 ± 1.2, p = 0.02 and 2.6 ± 0.3 vs 2.4 ± 0.3, p = 0.16, respectively). The respiratory motion-correction did not lead to a change in the signal to noise ratio. Conclusion The proposed respiratory motion correction method for hybrid PET/MRI improved the image quality of cardiovascular PET scans by increased SUVmax and TBRmax values while maintaining the signal-to-noise ratio. Trial registration METC162043 registered 01/03/2017.
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    Highly efficient image navigator based 3D whole-heart cardiac MRA at 0.55T
    (2024) Castillo-Passi, Carlos; Kunze, Karl P.; Crabb, Michael G.; Munoz, Camila; Fotaki, Anastasia; Neji, Radhouene; Irarrazaval, Pablo; Prieto, Claudia; Botnar, Rene M.
    PurposeTo develop and evaluate a highly efficient free-breathing and contrast-agent-free three-dimensional (3D) whole-heart Cardiac Magnetic Resonance Angiography (CMRA) sequence at 0.55T.MethodsFree-breathing whole-heart CMRA has been previously proposed at 1.5 and 3T. Direct application of this sequence to 0.55T is not possible due to changes in the magnetic properties of the tissues. To enable free-breathing CMRA at 0.55T, pulse sequence design and acquisition parameters of a previously proposed whole-heart CMRA framework are optimized via Bloch simulations. Image navigators (iNAVs) are used to enable nonrigid respiratory motion-correction and 100% respiratory scan efficiency. Patch-based low-rank denoising is employed to accelerate the scan and account for the reduced signal-to-noise ratio at 0.55T. The proposed approach was evaluated on 11 healthy subjects. Image quality was assessed by a clinical expert (1: poor to 5: excellent) for all intrapericardiac structures. Quantitative evaluation was performed by assessing the vessel sharpness of the proximal right coronary artery (RCA).ResultsOptimization resulted in an imaging flip angle of 110 degrees$$ 11{0}<^>{\circ } $$, fat saturation flip angle of 180 degrees$$ 18{0}<^>{\circ } $$, and six k-space lines for iNAV encoding. The relevant cardiac structures and main coronary arteries were visible in all subjects, with excellent image quality (mean 4.9/5.0$$ 4.9/5.0 $$) and minimal artifacts (mean 4.9/5.0$$ 4.9/5.0 $$), with RCA vessel sharpness (50.3%+/- 9.8%$$ 50.3\%\pm 9.8\% $$) comparable to previous studies at 1.5T.ConclusionThe proposed approach enables 3D whole-heart CMRA at 0.55T in a 6-min scan (5.9 +/- 0.7 min$$ 5.9\pm 0.7\;\min $$), providing excellent image quality, minimal artifacts, and comparable vessel sharpness to previous 1.5T studies. Future work will include the evaluation of the proposed approach in patients with cardiovascular disease.
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    Motion-corrected simultaneous cardiac positron emission tomography and coronary MR angiography with high acquisition efficiency
    (2018) Munoz, Camila; Neji, Radhouene; Cruz, Gastão; Mallia, Andrew; Jeljeli, Sami; Reader, Andrew J.; Botnar, René Michael; Prieto Vásquez, Claudia
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    MRI-Guided Motion-Corrected PET Image Reconstruction for Cardiac PET/MRI
    (SOC NUCLEAR MEDICINE INC, 2021) Munoz, Camila; Ellis, Sam; Nekolla, Stephan G.; Kunze, Karl P.; Vitadello, Teresa; Neji, Radhouene; Botnar, Rene M.; Schnabel, Julia A.; Reader, Andrew J.; Prieto, Claudia
    Simultaneous PET/MRI has shown potential for the comprehensive assessment of myocardial health from a single examination. Furthermore, MRI-derived respiratory motion information, when incorporated into the PET image reconstruction, has been shown to improve PET image quality. Separately, MRI-based anatomically guided PET image reconstruction has been shown to effectively denoise images, but this denoising has so far been demonstrated mainly in brain imaging. To date, the combined benefits of motion compensation and anatomic guidance have not been demonstrated for myocardial PET/MRI. This work addressed this lack by proposing a single cardiac PET/MRI image reconstruction framework that fully utilizes MRI-derived information to allow both motion compensation and anatomic guidance within the reconstruction. Methods: Fifteen patients underwent an F-18-FDG cardiac PET/MRI scan with a previously introduced acquisition framework. The MRI data processing and image reconstruction pipeline produces respiratory motion fields and a high-resolution respiratory motion-corrected MR image with good tissue contrast. This MRI-derived information was then included in a respiratory motion-corrected, cardiac-gated, anatomically guided image reconstruction of the simultaneously acquired PET data. Reconstructions were evaluated by measuring myocardial contrast and noise and were compared with images from several comparative intermediate methods using the components of the proposed framework separately. Results: Including respiratory motion correction, cardiac gating, and anatomic guidance significantly increased contrast. In particular, myocardiumto-blood pool contrast increased by 143% on average (P < 0.0001), compared with conventional uncorrected, non-guided PET images. Furthermore, anatomic guidance significantly reduced image noise, by 16.1%, compared with nonguided image reconstruction (P < 0.0001). Conclusion: The proposed framework for MRI-derived motion compensation and anatomic guidance of cardiac PET data significantly improved image quality compared with alternative reconstruction methods. Each component of the reconstruction pipeline had a positive impact on the final image quality. These improvements have the potential to improve clinical interpretability and diagnosis based on cardiac PET/MR images.
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    Non-rigid motion-compensated 3D whole-heart T2 mapping in a hybrid 3T PET-MR system
    (2024) Schneider, Alina; Munoz, Camila; Hua, Alina; Ellis, Sam; Jeljeli, Sami; Kunze, Karl P.; Neji, Radhouene; Reader, Andrew J.; Reyes, Eliana; Ismail, Tevfik F.; Botnar, Rene M.; Prieto, Claudia
    Purpose: Simultaneous PET-MRI improves inflammatory cardiac disease diagnosis. However, challenges persist in respiratory motion and mis-registration between free-breathing 3D PET and 2D breath-held MR images. We propose a free-breathing non-rigid motion-compensated 3D T-2-mapping sequence enabling whole-heart myocardial tissue characterization in a hybrid 3T PET-MR system and provides non-rigid respiratory motion fields to correct also simultaneously acquired PET data.Methods: Free-breathing 3D whole-heart T-2-mapping was implemented on a hybrid 3T PET-MRI system. Three datasets were acquired with different T-2-preparation modules (0, 28, 55 ms) using 3-fold under sampled variable-density Cartesian trajectory. Respiratory motion was estimated via virtual 3D image navigators, enabling multi-contrast non-rigid motion-corrected MR reconstruction. T-2-maps were computed using dictionary-matching. Approach was tested in phantom, 8 healthy subjects, 14 MR only and 2 PET-MR patients with suspected cardiac disease and compared with spin echo reference (phantom) and clinical 2D T-2-mapping (in-vivo).Results: Phantom results show a high correlation (R-2 = 0.996) between proposed approach and gold standard 2D T-2 mapping. In-vivo 3D T-2-mapping average values in healthy subjects (39.0 +/- 1.4 ms) and patients (healthy tissue) (39.1 +/- 1.4 ms) agree with conventional 2D T-2-mapping (healthy = 38.6 +/- 1.2 ms, patients = 40.3 +/- 1.7 ms). Bland-Altman analysis reveals bias of 1.8 ms and 95% limits of agreement (LOA) of -2.4-6 ms for healthy subjects, and bias of 1.3 ms and 95% LOA of -1.9 to 4.6 ms for patients.Conclusion: Validated efficient 3D whole-heart T-2-mapping at hybrid 3T PET-MRI provides myocardial inflammation characterization and non-rigid respiratory motion fields for simultaneous PET data correction. Comparable T-2 values were achieved with both 3D and 2D methods. Improved image quality was observed in the PET images after MR-based motion correction.
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    Non-rigid motion-corrected free-breathing 3D myocardial Dixon LGE imaging in a clinical setting
    (SPRINGER, 2022) Zeilinger, Martin Georg; Kunze, Karl Philipp; Munoz, Camila; Neji, Radhouene; Schmidt, Michaela; Croisille, Pierre; Heiss, Rafael; Wuest, Wolfgang; Uder, Michael; Botnar, Rene Michael; Treutlein, Christoph; Prieto, Claudia
    Objectives To investigate the efficacy of an in-line non-rigid motion-compensated reconstruction (NRC) in an image-navigated high-resolution three-dimensional late gadolinium enhancement (LGE) sequence with Dixon water-fat separation, in a clinical setting. Methods Forty-seven consecutive patients were enrolled prospectively and examined with 1.5 T MRI. NRC reconstructions were compared to translational motion-compensated reconstructions (TC) of the same datasets in overall and different sub-category image quality scores, diagnostic confidence, contrast ratios, LGE pattern, and semiautomatic LGE quantification. Results NRC outperformed TC in all image quality scores (p < 0.001 to 0.016; e.g., overall image quality 5/5 points vs. 4/5). Overall image quality was downgraded in only 23% of NRC datasets vs. 53% of TC datasets due to residual respiratory motion. In both reconstructions, LGE was rated as ischemic in 11 patients and non-ischemic in 10 patients, while it was absent in 26 patients. NRC delivered significantly higher LGE-to-myocardium and blood-to-myocardium contrast ratios (median 6.33 vs. 5.96, p < 0.001 and 4.88 vs. 4.66, p < 0.001, respectively). Automatically detected LGE mass was significantly lower in the NRC reconstruction (p < 0.001). Diagnostic confidence was identical in all cases, with high confidence in 89% and probable in 11% datasets for both reconstructions. No case was rated as inconclusive. Conclusions The in-line implementation of a non-rigid motion-compensated reconstruction framework improved image quality in image-navigated free-breathing, isotropic high-resolution 3D LGE imaging with undersampled spiral-like Cartesian sampling and Dixon water-fat separation compared to translational motion correction of the same datasets. The sharper depictions of LGE may lead to more accurate measures of LGE mass.
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    Self-supervised learning-based diffeomorphic non-rigid motion estimation for fast motion-compensated coronary MR angiography
    (ELSEVIER SCIENCE INC, 2022) Munoz, Camila; Qi, Haikun; Cruz, Gastao; Kuestner, Thomas; Botnar, Rene M.; Prieto, Claudia
    Purpose: To accelerate non-rigid motion corrected coronary MR angiography (CMRA) reconstruction by developing a deep learning based non-rigid motion estimation network and combining this with an efficient implementation of the undersampled motion corrected reconstruction.
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    Severe acute pancreatitis secondary to hypertriglyceridemia as the onset of Type 1 Diabetes Mellitus in the pediatric age
    (2024) Munoz, Camila; De Toro, Valeria; Gana, Juan Cristobal; Harris, Paul R.; Loureiro, Carolina; Alberti, Gigliola
    Hypertriglyceridemia (HTG)-induced acute pancreatitis (AP) secondary to insulin deficiency following the onset of type 1 diabetes mellitus (T1DM) is a rare but serious complication in children. Objective: To describe the diagnosis and treatment of severe HTG and to emphasize the need for timely diagnosis of T1DM. Clinical Case: A 15-year-old female adolescent with a history of overweight presented with a two-weeks history of fever, anorexia, and diffuse abdominal pain. Laboratory tests revealed triglycerides of 17,580 mg/dL, lipase of 723 U/L, and blood glucose of 200 mg/dL. An abdominal CT scan showed an enlarged and edematous pancreas. She was hospitalized with a diagnosis of AP and severe HTG, which progressed to acute necro-hemorrhagic pancreatitis. Treatment included continuous intravenous insulin infusion until triglyceride levels decreased. Upon discontinuation of insulin, fasting hyperglycemia (206 mg/dL) and metabolic acidosis recurred, therefore DM was suspected. Upon targeted questioning, a history of polydipsia, polyuria, and weight loss during the last 3 months stood out. Glycated hemoglobin was markedly elevated (14.7%). Insulin therapy was optimized, achieving stabilization of laboratory parameters after 15 days of treatment and complete anatomical resolution of pancreatic involvement at one year of follow-up. Conclusions: The presence of severe HTG in pediatrics compels us to consider its secondary causes, such as the onset of T1DM. It is crucial to improve the ability to diagnose T1DM early, as it may present with infrequent and high-risk presentations for the patient.
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    Whole-heart non-rigid motion corrected coronary MRA with autofocus virtual 3D iNAV
    (ELSEVIER SCIENCE INC, 2022) Schneider, Alina; Cruz, Gastao; Munoz, Camila; Hajhosseiny, Reza; Kuestner, Thomas; Kunze, Karl P.; Neji, Radhouene; Botnar, Rene M.; Prieto, Claudia
    Purpose: Respiratory motion-corrected coronary MR angiography (CMRA) has shown promise for assessing coronary disease. By incorporating coronal 2D image navigators (iNAVs), respiratory motion can be corrected for in a beat-to-beat basis using translational correction in the foot-head (FH) and right-left (RL) directions and in a bin-to-bin basis using non-rigid motion correction addressing the remaining FH, RL and anterior-posterior (AP) motion. However, with this approach beat-to-beat AP motion is not corrected for. In this work we investigate the effect of remaining beat-to-beat AP motion and propose a virtual 3D iNAV that exploits autofocus motion correction to enable beat-to-beat AP and improved RL intra-bin motion correction. Methods: Free-breathing 3D whole-heart CMRA was acquired using a 3-fold undersampled variable-density Cartesian trajectory. Beat-to-beat 3D translational respiratory motion was estimated from the 2D iNAVs in FH and RL directions, and in AP direction with autofocus assuming a linear relationship between FH and AP movement of the heart. Furthermore, motion in RL was also refined using autofocus. This virtual 3D (v3D) iNAV was incorporated in a non-rigid motion correction (NRMC) framework. The proposed approach was tested in 12 cardiac patients, and visible vessel length and vessel sharpness for the right (RCA) and left (LAD) coronary arteries were compared against 2D iNAV-based NRMC. Results: Average vessel sharpness and length in v3D iNAV NRMC was improved compared to 2D iNAV NRMC (vessel sharpness: RCA: 56 +/- 1% vs 52 +/- 11%, LAD: 49 +/- 8% vs 49 +/- 7%; visible vessel length: RCA: 5.98 +/- 1.37 cm vs 5.81 +/- 1.62 cm, LAD: 5.95 +/- 1.85 cm vs 4.83 +/- 1.56 cm), however these improvements were not statistically significant. Conclusion: The proposed virtual 3D iNAV NRMC reconstruction further improved NRMC CMRA image quality by reducing artefacts arising from residual AP motion, however the level of improvement was subject-dependent.