Late Magnetic Resonance Imaging Research Articles

Distinguishing multicystic from focal encephalomalacia on delayed MRI in children with term hypoxic ischemic injury.

To define cystic patterns resulting from term hypoxic ischemic injury (HII) on delayed Magnetic Resonance Imaging (MRI) and determine associated HII patterns and lesions that reflect the severity of injury, from a database of African children with cerebral palsy. Retrospective review of 1175 children with cerebral palsy due to term HII diagnosed on late MRI, identifying those with cystic changes. These were classified as multicystic or (multi-) focal-cystic, and were evaluated for associated injuries-thalami, basal ganglia, hippocampi, cerebellum, and presence of ulegyria. Three hundred and eighty-eight of 1175 (33%) children had cystic encephalomalacia. Two hundred and seven of 388 (53.3%) had focal-cystic and 181/388 (46.6%) had multicystic injury. The focal-cystic group comprised 87.9% (182/207) with thalamic injury, 25.6% (53/207) with basal ganglia injury, and 15% (31/207) with cerebellar involvement. Basal-ganglia-thalamus (BGT) pattern was present in 43.9% (91/207) and ulegyria in 69.6% (144/207). In the multicystic group, 88.9% (161/181) had thalamic injury, 30.9% (56/181) had basal ganglia injury, and 21% (38/181) had cerebellar involvement. BGT pattern was observed in 29.8% (54/181) and ulegyria in 28.7%. (52/181). Significant associations (p<.05) were found between multicystic injury and caudate/globus pallidus involvement, and between focal-cystic pattern of injury and ulegyria. Cystic encephalomalacia was seen in almost one-third of patients with term HII imaged with delayed MRI, with a similar prevalence of focal-cystic and multicystic injury. Multicystic injury was associated with caudate and globus pallidi involvement, typical of the BGT pattern of HII, whereas the focal-cystic pattern was associated with ulegyria, typical of watershed injury.

Effect of Early Postoperative Resolution of MRI Signal Intensity Changes on the Outcomes of Degenerative Cervical Myelopathy.

A retrospective cohort study. To investigate whether the timing of postoperative resolution of increased signal intensity (ISI) in the spinal cord is associated with surgical outcomes. It remains unclear whether changes in ISI in the early postoperative period influence surgical outcomes. This retrospective cohort study evaluated consecutive patients undergoing surgery for degenerative cervical myelopathy at a single academic hospital between January 2012 and September 2019. These patients underwent magnetic resonance imaging (MRI) preoperatively, within two weeks postoperatively (early MRI) and after six months postoperatively (late MRI). ISI was classified as follows: grade 0, none; grade 1, light (obscure); and grade 2, intense (bright). Patients were categorized into the following three groups: those with postoperative ISI resolution at early MRI (group E) or only at the late MRI (group L) stage and those whose ISI was persistent (group P). The surgical outcomes were compared between these three groups. We included 204 patients with complete data eligible for the analysis, and 163 of them had preoperative ISI. Postoperative ISI regression was observed in 49 (30.1%) patients. Of these 49 patients, 25 showed ISI resolution at early MRI (group E) and 24 only at late MRI (group L). All 49 were grade 1 on preoperative MRI, and this was not found to significantly impact surgical outcomes. In comparing surgical outcomes between the groups, group E had better postoperative Japanese Orthopedic Association scores and Japanese Orthopedic Association recovery rates than groups L and P. No significant differences were observed between groups L and P. Early resolution of preoperative grade 1 ISI on postoperative T2-weighted MRI may be associated with better surgical outcomes in patients with degenerative cervical myelopathy undergoing cervical spinal surgery.

1051. Cardiac Assessment in Children with MIS-C: Late Magnetic Resonance Imaging Features

Abstract Background Multisystem Inflammatory Syndrome (MIS-C), a new entity in children which developed 2-4 weeks after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, is a severe condition. It can affect the multisystem, while the most severe manifestation is cardiac involvement. Left ventricular dysfunction, cardiogenic shock, coronary artery dilatation/aneurysm, valvulitis, pericardial effusion, arrhythmia, and conduction abnormalities were reported in approximately 80% of children with cardiovascular system involvement. It is still unclear the duration of the cardiac symptoms, and even they are permanent or persistent. Few studies evaluated persistent cardiac abnormalities by cardiac magnetic resonance imaging (MRI). Therefore, we aimed to assess persisting cardiac abnormalities with MIS-C by cardiac MRI and compare them with echocardiograms. Methods A retrospective study was conducted at a tertiary-level University Hospital between June 2020-July 2021. Thirty-four children diagnosed with MIS-C according to the criteria defined by the Centers for Disease Control and Prevention were retrospectively evaluated. Results The study included 17 males and 17 females with a mean age of 9.31±4.72 years. Initial echocardiographic evaluation showed cardiac abnormality in 18 (52.9%) patients; 4 (11.8%) pericardial effusion, 4 (11.8%) left ventricular ejection fraction (LVEF) &amp;lt; 55%, 5 (14.7%) LV fractional shortening &amp;lt; 30%, 5 (14.7%) coronary artery dilatation. Echocardiography showed normal LV systolic function in all patients at follow-up; coronary dilatation persisted in 2 of 5 (40 %) patients at the 6th-month visit. Cardiac MRI was performed in 31 (91.2%) patients. We didn’t detect abnormal T1 levels, whereas 9 (29%) had isolated elevated T2 values. 19 (61.3%) of 31 patients had at least one of the following findings: pericardial effusion, right ventricular dysfunction, LVEF abnormality. Conclusion Cardiac involvement persisted at a higher rate which was shown by cardiac MRI in the late period, particularly pericardial effusion. Cardiac MRI may be suggested for all MIS-C patients at a later phase. Prospective studies with larger sample sizes are needed to determine long-term cardiac effects. Disclosures All Authors: No reported disclosures.

The reliability of Juvenile Arthritis Magnetic Resonance Imaging Scoring system in the evaluation of the shoulder joint in juvenile idiopathic arthritis.

We aimed to evaluate shoulder joint by magnetic resonance imaging (MRI) using the Juvenile Arthritis Magnetic Resonance Imaging Scoring (JAMRIS) system in children with juvenile idiopathic arthritis (JIA) and to compare clinical, laboratory parameters and disease activity scores with MRI parameters. A total of 32 shoulder joints of 20 patients (16 males, 4 females; mean age: 8.9±3.5 years; range, 2.5 to 14 years) with a known diagnosis of JIA and a clinical suspicion of shoulder joint involvement and underwent MRI were included. Reliability was determined by inter- and intra-observer correlation coefficients. Correlation of the clinical and laboratory parameters with JAMRIS scores was done using the non-parametric tests. Sensitivity of clinical examination to detect shoulder joint arthritis was also determined. Of the 32 joints, 27 joints in 17 patients showed MRI changes. Seven joints in five patients fulfilled the definition of clinical arthritis, all revealed MRI changes. In 25 joints without clinical arthritis, early and late MRI changes were seen in 19 (67%) and 12 (48%) joints, respectively. The inter- and intra-observer correlation coefficients for JAMRIS system were excellent. No correlation was found between MRI parameters, clinical, laboratory, and disease activity scores. The sensitivity of clinical examination to detect shoulder joint arthritis was 25.9%. The JAMRIS system is reliable and reproducible to determine shoulder joint inflammation in JIA. Detection of shoulder joint arthritis by clinical examination has a poor sensitivity.

Cardiac Assessment in Children with MIS-C: Late Magnetic Resonance Imaging Features.

Multisystem Inflammatory Syndrome (MIS-C) is a new entity that emerges 2–4 weeks after the SARS-CoV-2 infection in children. MIS-C can affect all systems, the most severe of which is cardiac involvement. The duration of the cardiac symptoms is still uncertain and may be persistent or prolonged. The American College of Rheumatology Clinical Guidelines recommends cardiac magnetic resonance imaging (MRI) 2–6 months after the diagnosis of MIS-C in patients presenting with significant transient left ventricular (LV) dysfunction in the acute phase of illness (LV ejection fraction 50%) or persistent LV dysfunction. There are a few studies investigating cardiac MRI findings in MIS-C patients. In this study, we aimed to evaluate cardiac MRI findings, at the earliest 3 months after diagnosis, and compare these findings with the echocardiograms in children with MIS-C. A retrospective study including 34 MIS-C patients was conducted at a tertiary-level University Hospital between June 2020 and July 2021. Centers for Disease Control and Prevention criteria were used in the diagnosis of MIS-C. Cardiac MRI was performed at least 3 months after MIS-C diagnosis. The study included 17 (50%) boys and 17 (50%) girls with a mean age of 9.31 ± 4.72 years. Initial echocardiographic evaluation revealed cardiac abnormality in 13 (38.2) patients; 4 (11.8%) pericardial effusion, 4 (11.8%) left ventricular ejection fraction (LVEF) < 55%, and 5 (14.7%) coronary artery dilatation. Echocardiography showed normal LV systolic function in all patients during follow-up; coronary dilatation persisted in 2 of 5 (40%) patients at the 6th-month visit. Cardiac MRI was performed in 31 (91.2%) patients, and myocardial hyperemia was not detected in any patients (T1 relaxation time was < 1044 ms in all children). However, 9 (29%) patients’ MRI showed isolated elevated T2 levels, and 19 (61.3%) revealed at least one of the following findings: pericardial effusion, right ventricular dysfunction, or LVEF abnormality. In patients with MIS-C, a high rate of cardiac involvement, particularly pericardial effusion was determined by cardiac MRI performed at the earliest 2–6 months after diagnosis. Even if echocardiography does not reveal any abnormality in the initial phase, cardiac MRI should be suggested in MIS-C patients in the late period. This is the first study reporting cardiac MRI findings in the late period of MIS-C patients.

Ventricular tachycardia ablation guided or aided by scar characterization with cardiac magnetic resonance: rationale and design of VOYAGE study

BackgroundRadiofrequency ablation has been shown to be a safe and effective treatment for scar-related ventricular arrhythmias (VA). Recent preliminary studies have shown that real time integration of late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) images with electroanatomical map (EAM) data may lead to increased procedure efficacy, efficiency, and safety.MethodsVOYAGE is a prospective, randomized, multicenter controlled open label study designed to compare in terms of efficacy, efficiency, and safety a CMR aided/guided workflow to standard EAM-guided ventricular tachycardia (VT) ablation. Patients with an ICD or with ICD implantation expected within 1 month, with scar related VT, suitable for CMR and multidetector computed tomography (MDCT) will be randomized to a CMR-guided or CMR-aided approach, whereas subjects unsuitable for imaging or with image quality deemed not sufficient for postprocessing will be allocated to standard of care ablation. Primary endpoint is defined as VT recurrences (sustained or requiring appropriate ICD intervention) during 12 months follow-up, excluding the first month of blanking period. Secondary endpoints will include procedural efficiency, safety, impact on quality of life and comparison between CMR-guided and CMR-aided approaches. Patients will be evaluated at 1, 6 and 12 months.DiscussionThe clinical impact of real time CMR-guided/aided ablation approaches has not been thoroughly assessed yet. This study aims at defining whether such workflow results in more effective, efficient, and safer procedures. If proven to be of benefit, results from this study could be applied in large scale interventional practice.Trial registrationClinicalTrials.gov, NCT04694079, registered on January 1, 2021.

An Updated Overview of MRI Injuries in Neonatal Encephalopathy: LyTONEPAL Cohort.

Background: Brain magnetic resonance imaging (MRI) is a key tool for the prognostication of encephalic newborns in the context of hypoxic−ischemic events. The purpose of this study was to finely characterize brain injuries in this context. Methods: We provided a complete, descriptive analysis of the brain MRIs of infants included in the French national, multicentric cohort LyTONEPAL. Results: Among 794 eligible infants, 520 (65.5%) with MRI before 12 days of life, grade II or III encephalopathy and gestational age ≥36 weeks were included. Half of the population had a brain injury (52.4%); MRIs were acquired before 6 days of life among 247 (47.5%) newborns. The basal ganglia (BGT), white matter (WM) and cortex were the three predominant sites of injuries, affecting 33.8% (n = 171), 33.5% (n = 166) and 25.6% (n = 128) of participants, respectively. The thalamus and the periventricular WM were the predominant sublocations. The BGT, posterior limb internal capsule, brainstem and cortical injuries appeared more frequently in the early MRI group than in the late MRI group. Conclusion: This study described an overview of brain injuries in hypoxic−ischemic neonatal encephalopathy. The basal ganglia with the thalamus and the WM with periventricular sublocation injuries were predominant. Comprehensive identification of brain injuries in the context of HIE may provide insight into the mechanism and time of occurrence.

Abnormal Extracardiac Development in Fetuses With Congenital Heart Disease

BackgroundKnowledge about extracardiac anomalies (ECA) in fetal congenital heart disease (CHD) can improve our understanding of the developmental origins of various outcomes in these infants. The prevalence and spectrum of ECA, including structural brain anomalies (SBA), on magnetic resonance imaging (MRI) in fetuses with different types of CHD and at different gestational ages, is unknown. ObjectivesThe purpose of this study was to evaluate ECA rates and types on MRI in fetuses with different types of CHD and across gestation. MethodsA total of 429 consecutive fetuses with CHD and MRI between 17 and 38 gestational weeks were evaluated. ECA and SBA rates were assessed for each type of CHD and classified by gestational age (<25 or ≥25 weeks) at MRI. ResultsOf all 429 fetuses with CHD, 243 (56.6%) had ECA on MRI, and 109 (25.4%) had SBA. Among the 191 fetuses with normal genetic testing results, the ECA rate was 54.5% and the SBA rate 19.4%. Besides SBA, extrafetal (21.2%) and urogenital anomalies (10.7%) were the most prevalent ECA on MRI in all types of CHD. Predominant SBA were anomalies of hindbrain-midbrain (11.0% of all CHD), dorsal prosencephalon (10.0%) development, and abnormal cerebrospinal fluid spaces (10.5%). There was no difference in the prevalence or pattern of ECA between early (<25 weeks; 45.7%) and late (≥25 weeks; 54.3%) fetal MRI. ConclusionsECA and SBA rates on fetal MRI are high across all types of CHD studied, and ECA as well as SBA are already present from midgestation onward.

Identifying Myocardial Infarction Using Hierarchical Template Matching-Based Myocardial Strain: Algorithm Development and Usability Study.

BackgroundMyocardial infarction (MI; location and extent of infarction) can be determined by late enhancement cardiac magnetic resonance (CMR) imaging, which requires the injection of a potentially harmful gadolinium-based contrast agent (GBCA). Alternatively, emerging research in the area of myocardial strain has shown potential to identify MI using strain values.ObjectiveThis study aims to identify the location of MI by developing an applied algorithmic method of circumferential strain (CS) values, which are derived through a novel hierarchical template matching (HTM) method.MethodsHTM-based CS H-spread from end-diastole to end-systole was used to develop an applied method. Grid-tagging magnetic resonance imaging was used to calculate strain values in the left ventricular (LV) myocardium, followed by the 16-segment American Heart Association model. The data set was used with k-fold cross-validation to estimate the percentage reduction of H-spread among infarcted and noninfarcted LV segments. A total of 43 participants (38 MI and 5 healthy) who underwent CMR imaging were retrospectively selected. Infarcted segments detected by using this method were validated by comparison with late enhancement CMR, and the diagnostic performance of the applied algorithmic method was evaluated with a receiver operating characteristic curve test.ResultsThe H-spread of the CS was reduced in infarcted segments compared with noninfarcted segments of the LV. The reductions were 30% in basal segments, 30% in midventricular segments, and 20% in apical LV segments. The diagnostic accuracy of detection, using the reported method, was represented by area under the curve values, which were 0.85, 0.82, and 0.87 for basal, midventricular, and apical slices, respectively, demonstrating good agreement with the late-gadolinium enhancement–based detections.ConclusionsThe proposed applied algorithmic method has the potential to accurately identify the location of infarcted LV segments without the administration of late-gadolinium enhancement. Such an approach adds the potential to safely identify MI, potentially reduce patient scanning time, and extend the utility of CMR in patients who are contraindicated for the use of GBCA.

Early Versus Late Brain Magnetic Resonance Imaging after Neonatal Hypoxic Ischemic Encephalopathy Treated with Therapeutic Hypothermia

To evaluate the agreement in brain injury findings between early and late magnetic resonance imaging (MRI) in newborn infants with hypoxic-ischemic encephalopathy treated with therapeutic hypothermia and to compare the ability of early vs late MRI to predict early neurodevelopmental outcomes. This was a prospective longitudinal study of 49 patients with hypoxic-ischemic encephalopathy who underwent therapeutic hypothermia and had MRI performed at both <7 and≥7days of age. MRIs were reviewed by an experienced neuroradiologist and assigned brain injury severity scores according to established systems. Scores for early and late MRIs were assessed for agreement using the kappa statistic. The ability of early and late MRI scores to predict death or developmental delay at 15-30months of age was assessed by logistic regression analyses. Agreement between the early and late MRI was substantial to near perfect (k>0.75, P<.001) across MRI scoring systems. In cases of discrepant scoring, early MRI was more likely to identify severe injury when compared with late MRI. Early MRI scores were more consistently predictive of adverse outcomes compared with late MRI. The results of this study suggest that a single MRI performed in the first week after birth is adequate to assess brain injury and offer prognostic information in this high-risk population.

New surgical paradigm for open neural tube defects.

An open neural tube defect (ONTD) features an exposed, unclosed neural plate in the form of an expanded, flat, and frequently hefty neural placode. Traditional philosophy of ONTD repair aims at preserving function at any cost, which often means stuffing the entire thick and unwieldy but non-functional placode into a tight dural sac, increasing the likelihood of future tethering of the spinal cord. The same philosophy of attempting to save the whole perimetry of the placode also sometimes leads to inadvertent inclusion of parts of the squamous epithelial membrane surrounding the placode into the reconstructed product, only to form inclusion dermoid cyst causing further injury to the neural tissues. Lastly, defective closure of the caudal primary neural tube usually results in abolition of secondary and junctional neurulation, leaving a defective conus and sacral nerve roots, clinically presenting in most cases with neurogenic bladder and bowel dysfunction. Preserving this trapped but locally active sacral micturition center, isolated from suprasegmental inhibitory moderation, leads to a spastic, hyperactive, low compliance, and high-pressure bladder predisposing to upstream kidney damage, without benefits of normal bladder function. We report the post-natal surgical treatment of 8 newborn infants with ONTD, in which we resected the non-functional portion of the neural placode identified as such by direct spinal cord/placode and nerve root stimulation, as well as by transcortical evoked motor responses to check for suprasegmental corticospinal connectivity. Any part of the placode without local function or upstream connections was resected, and the small caudal spinal cord stump closed with pia-to-pia microsutures. The patients were followed for pre- and post-operative neuro-urological status and with serial magnetic resonance imaging (MRI) at 3weeks, 6months, and 2years post-repair. Follow-up period ranged from birth to 3years (mean of 24months). Of the 8 patients analyzed, 7 had a terminal and one a segmental ONTD. Pre-operative neurological level ranged from L4 to S2. Applying our new surgical paradigm, we found no neurological worsening post-operatively. All patients had a neurogenic bladder and bowel dysfunction but none had a high-pressure bladder on urodynamics studies. Early and late MRIs all showed a loose and capacious neural placode to dural sac relationship. None had an inclusion dermoid cyst. We propose a new paradigm for the surgical repair of open neural tube defects with intraoperative neuromonitoring and introduce a safe and reliable technique of placode debulking.

Liver function quantification of patients with portal vein embolization using dynamic contrast-enhanced MRI for assessment of hepatocyte uptake and elimination

PurposeWe evaluated pharmacokinetic models which quantify liver function including biliary elimination based on a dynamic Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI) technique with sparse data collection feasible in clinical routine. MethodsTwelve patients with embolized liver segments following interventional treatment of primary liver cancer or hepatic metastasis underwent MRI. During Gd-EOB-DTPA bolus administration, a 3D dynamic gradient-echo (GRE) MRI examination was performed over approx. 28 min. Interrupted data sampling was started approx. 5 min after contrast agent administration. Different implementations of dual-inlet models were tested, namely the Euler method (DE) and convolution with residue functions (C). A simple uptake model (U) and an uptake- elimination model (UE) extended by incorporating the biliary contrast agent elimination rate (Ke) were evaluated. ResultsThe uptake-elimination model, calculated via the simple Euler method (UE- DE) and by convolution (UE-C), yielded similar overall estimates in terms of fitting quality and agreement with published values. The Euler method was approx. 50 times faster and yielded a mean elimination rate of Ke=1.8±1.2mL/(min·100 mL) in nonembolized liver tissue, which was significantly higher (p=8.8·10-4) than in embolized tissue Ke=0.4±0.4 mL/(min·100 mL). Fractional hepatocyte volume vh was not significantly higher in nonembolized tissue (52.4 ± 13.4 mL/100 mL) compared to embolized tissue (44.4 ± 26.1 mL/100 mL). ConclusionsInterrupted late enhancement MRI data sampling in conjunction with the uptake-elimination model, deconvolved by integration of the differential rate equation and combined with the simple uptake model implemented with the Euler method (U-DE), turned out to be a stable and practical method for reliable noninvasive assessment of liver function.

P1010Association between left atrial fibrosis detected by cardiac magnetic resonance and endocardial electroanatomic mapping in the evaluation of the electrophysiological substrate in atrial fibrillation

Abstract Background Atrial fibrillation (AF) is related to left atrial fibrosis, but its identification by late magnetic resonance imaging (LGE) with gadolinium (LGE) persists in controversy due to heterogeneous results in its correlation with the electroatomic map (EAM) and the difficulty of perform histological studies in humans. Purpose We try to examine the point-by-point association between high density EAM and LGE-MRI using an automatic and reproducible method. Methods A LGE-MRI was performed in 16 patients prior to ablation. Three different areas were established depending on the intensity of normalized enhancement for each patient according to their blood group with the image intensity ratio (IIR) (healthy &amp;lt;1.20, border area (BZ) ≥1.20 &amp;lt;1.32 and scar ≥1.32). The high density electroanatomic maps of the left atrium (LA) were projected onto the MRI, obtaining an automatic correlation point by point. Results The study obtained significant differences (p &amp;lt; 0.001) between voltage (mV) and CV (mm/ms) among healthy, BZ and scar areas, as well a significant inverse correlation (p &amp;lt; 0.001) between voltage and IIR (R=-0.39). It obtained too a significant correlation between CV and IIR (R=-0.24), but this showed a greater correlation in those patients who have the least dilated LA (p = 0.02). Conclusions LGE-MRI and EAM showed good correlation in delineating potential pathologic substrate in AF, but left atrium dilation could reduce the performance of the CMR in this task. Conduction velocity could be more sensitive than voltage and LGE-MRI to detect incipient substrate in AF. Voltage and conduction velocity values Area /IIR Velocity (mm/ms) Voltage (mV) I / &amp;lt;.20 1.036(0.913-1.158) 1.593(1.489-1.696) 2 / ≥1.20 and &amp;lt;1.32 0.722(0.590-0.850) 0.792 (0.649-0,935) 3 / ≥1.32 0.623(0.473-0,733) 0.444(0.245-0.642) Voltage and conduction velocity values in the three areas of the LGE-RMN. Abstract Figure. Correlation among voltage, VC and LA

Predictors of Outcomes in Hypoxic-Ischemic Encephalopathy following Hypothermia: A Meta-Analysis

Introduction: Prediction of neurodevelopmental outcome in infants with hypoxic-ischemic encephalopathy remains an important challenge. Various studies have shown that the predictive ability of different modalities changed after the introduction of therapeutic hypothermia. This paper reviews the diagnostic test accuracy of the different modalities that are being used to predict neurodevelopmental outcomes following therapeutic hypothermia. Methods: A systematic literature search was performed using Embase and PubMed. Two reviewers independently included eligible studies and extracted data. The quality of the studies was assessed using the Quality in Prognosis Studies Tool. Meta-analyses were performed where possible. Results: Forty-seven articles and 3 conference abstracts were included, reporting on 3,072infants of whom 39% died or had an adverse neurodevelopmental outcome. A meta-analysis could be performed using 37 articles on (amplitude-integrated) electroencephalography (EEG), conventional magnetic resonance imaging (MRI), diffusion-weighted imaging (DWI), and proton magnetic resonance spectroscopy (¹H-MRS). Amplitude-integrated EEG (aEEG) at 24 and 72 h showed similar high diagnostic OR, while aEEG at 6 h and EEG performed less, both due to a low specificity. For MRI, most studies reported scoring systems in which early (<8 days) MRI performed better than late (≥8 days) MRI. Injury to the posterior limb of the internal capsule on MRI or to the thalami on DWI were strong individual predictors, as was an increased lactate/N-acetylaspartate peak on ¹H-MRS. Conclusions: In the era of therapeutic hypothermia, the different modalities remain good predictors of neurodevelopmental outcome. However, timing should be taken into account. aEEG may initially be false positive and gets more reliable after 24 h. In contrast, MRI should be used during the first week, as its predictive value decreases afterwards.

Late Contrast Enhancing Brain Lesions in Proton-Treated Patients With Low-Grade Glioma: Clinical Evidence for Increased Periventricular Sensitivity and Variable RBE

Late radiation-induced contrast-enhancing brain lesions (CEBLs) on magnetic resonance imaging (MRI) after proton therapy of brain tumors have been observed to occur frequently in regions of high linear energy transfer (LET) and in proximity to the ventricular system. We analyzed 110 patients with low-grade glioma treated with proton therapy to determine whether the risk for CEBLs is increased in proximity to the ventricular system and if there is a relationship between relative biological effectiveness (RBE) and LET. We contoured CEBLs identified on follow-up T1-MRI scans and computed dose and dose-averaged LET (LETd) distributions for all patients using the Monte Carlo method. We then performed cross-validated voxel-level logistic regression to predict local risks for image change and to extract model parameters, such as the RBE. From the voxel-level model, we derived a model for patient-level risk prediction based on the treatment plan. Of 110 patients, 23 exhibited 1 or several CEBLs on follow-up MRI scans. The voxel-level logistic model has an accuracy as follows: area under the curve of 0.94 and Brier score of 2.6 × 10-5. Model predictions are a 3-fold increased risk in the 4 mm region around the ventricular system and an LETd-dependent RBE of, for example, 1.20 for LETd = 2 keV/μm and 1.50 for LETd = 5 keV/μm. The patient-level risk model has an accuracy as follows: area under the curve of 0.78 and Brier score of 0.13. Our findings present clinical evidence for an increased risk in ventricular proximity and for a proton RBE that increases significantly with increasing LET. We present a voxel-level model that accurately predicts the localization of late MRI contrast change and extrapolate a patient-level model that allows treatment plan-based risk prediction.

Prenatal magnetic resonance imaging within the 26th week of gestation may predict the fate of isolated upward rotation of the cerebellar vermis: insights from a multicentre study.

We investigated whether prenatal magnetic resonance imaging (MRI) within 26weeks of gestation (GW) may predict the fate of isolated upward rotation of the cerebellar vermis (URCV). This retrospective multicentre observational study included foetuses diagnosed with isolated URCV in prenatal MRI performed within 26 GW. Isolated URCV was defined by a brainstem-vermis angle (BVA) ≥ 12° in the MR midline sagittal view without abnormalities of the supratentorial structures, brainstem, or cerebellum hemispheres. The assessments included the BVA, clival-supraoccipital angle, transverse diameter of the posterior cranial fossa, tentorial angle, width of the cisterna magna (WCM), ventricular width, vermian diameters, hypointense stripes, and cerebellar tail sign. Late prenatal or postnatal MRI was used as a reference standard to assess the final vermian fate (rotated/de-rotated). Forty-five foetuses (mean GW at prenatal MRI = 21.5 ± 1.4weeks) were included. In the reference standard, the vermis was de-rotated in 26 cases (57.7%). At least two of the following criteria were used to predict the persistence of URCV at imaging follow-up: BVA ≥ 23°, WCM ≥ 9mm, and the cerebellar tail sign. The results were a sensitivity of 84.21% (95% CI, 60.4-96.6%), specificity of 80.8% (95% CI, 60.6-93.4%), positive predictive value of 76% (95% CI, 58.7-87.8%), and negative predictive value of 87.5% (95% CI, 70.9-95.2%). MRI within 26 GW on foetuses diagnosed with isolated URCV may predict delayed cerebellar vermis de-rotation, which is associated with good neurodevelopmental outcome in most cases. • Foetal MRI is a valuable tool in predicting the fate of isolated upward-rotated cerebellar vermis. • A wider angle between the brainstem and vermis is associated with higher risk of persistence of vermian rotation. • The presence of ≥ 2 factors among a brainstem-to-vermis angle ≥ 23°, width of the cisterna magna ≥ 9mm, and the presence of the "cerebellar tail sign" has a sensitivity of 84.21% (95% CI, 60.4-96.6%) and specificity of 80.8% (95% CI, 60.6-93.4%) in predicting the persistence of the vermian rotation at imaging follow-up.

Assessment of ventricular tachyarrhythmia in patients with hypertrophic cardiomyopathy with machine learning-based texture analysis of late gadolinium enhancement cardiac MRI

To assess the diagnostic value of machine learning-based texture feature analysis of late gadolinium enhancement images on cardiac magnetic resonance imaging (MRI) for assessing the presence of ventricular tachyarrhythmia (VT) in patients with hypertrophic cardiomyopathy. This retrospective study included 64 patients with hypertrophic cardiomyopathy who underwent cardiac MRI and 24-hour Holter monitoring within 1 year before cardiac MRI. There were 42 men and 22 women with a mean age of 48.13±13.06 (SD) years (range: 20-70 years). Quantitative textural features were extracted via manually placed regions of interest in areas with high and intermediate signal intensity on late gadolinium-chelate enhanced images. Feature selection and dimension reduction were performed. The diagnostic performances of machine learning classifiers including support vector machines, Naive Bayes, k-nearest-neighbors, and random forest for predicting the presence of VT were assessed using the results of 24-hour Holter monitoring as the reference test. All machine learning models were assessed with and without the application of the synthetic minority over-sampling technique (SMOTE). Of the 64 patients with hypertrophic cardiomyopathy, 21/64 (32.8%) had VT. Of eight machine learning models investigated, k-nearest-neighbors with SMOTE exhibited the best diagnostic accuracy for the presence or absence of VT. k-nearest-neighbors with SMOTE correctly identified 40/42 (95.2%) VT-positive patients and 40/43 (93.0%) VT-negative patients, yielding 95.2% sensitivity (95% CI: 82.5%-99.1%), 93.0% specificity (95% CI: 79.8%-98.1%) and 94.1% accuracy (95% CI: 88.8%-98%). Machine learning-based texture analysis of late gadolinium-chelate enhancement-positive areas is a promising tool for the classification of hypertrophic cardiomyopathy patients with and without VT.

High-Resolution MRI Vessel Wall Imaging in Acute Aneurysmal Subarachnoid Hemorrhage : Spatiotemporal Pattern and Clinicoradiologic Implications.

The spatiotemporal pattern of vessel wall changes was investigated on two time point magnetic resonance images (MRI) in patients with aneurysmal subarachnoid hemorrhages (aSAH) and its association with clinicoradiologic severity score and delayed cerebral ischemia (DCI) was analyzed. A total of 32 prospectively enrolled patients with aSAH (mean age 56.94 years; 9male and 23female) underwent vessel wall imaging (VWI) MRI. Of the patients 20 completed two time point MRIs early and late during the admission, 10patients only had early MRI and 2patients only had late MRI. Timing of early MRI had amean of 2.5days (range 1-6days) and late MRI had amean of 10.5 days (range 7-16 days) from time of admission. Spatiotemporal pattern of vessel wall enhancement (VWE), vasospasm, diffusion-weighted imaging (DWI) lesion burden (grade0-III) and infarcts were analyzed against the clinicoradiologic severity score (high-risk: vasograde red and yellow, low-risk: vasograde green) and DCI. On the early MRI, mild VWE alone was significantly more frequent in the high-risk group (36.7% versus 20.0%; P = 0.024). On the late MRI, vasospasm was significantly more frequent in the high-risk group (27.2% versus 4.5%; P = 0.022). Vasospasm infrequently showed mild VWE (6.67% on early MRI and 9.09% on late MRI). Both mild VWE alone on early MRI and on late MRI were significantly associated with development of DCI during the admission (P = 0.034 and P = 0.035, respectively). Mild VWE on early MRI and vasospasm on late MRI were significantly more prevalent in high-risk and DCI patients suggesting VWI might enable imaging of early neuroinflammatory changes which are part of the pathomechanism of vasospasm and DCI.

P602Septal function and viability determine response to cardiac resynchronization therapy

Abstract Introduction Cardiac resynchronization therapy (CRT) has evolved as an important treatment in patients with symptomatic heart failure, reduced left ventricular (LV) ejection fraction and wide QRS. However, as one third of patients do not benefit from the therapy, there is need for better selection criteria. Previous studies have shown an association between recovery of septal function and response to CRT. Purpose To test the hypothesis that septal dysfunction in the absence of scar predicts response to CRT. Methods In 121 patients undergoing CRT implantation according to current European Society of Cardiology guidelines, we performed speckle-tracking echocardiography and estimated LV pressure non-invasively based on a method recently innovated in our lab. Pressure-strain analysis was used to calculate myocardial work. Septal dysfunction with asymmetric LV workload was calculated as the difference between LV lateral wall and septal work. Late gadolinium enhancement cardiac magnetic resonance imaging (LGE-CMR) was performed to assess septal scar. CRT response was defined as ≥15% reduction of LV end systolic volume by echocardiography at 6 months follow-up. Results Eighty-eight patients (73%) responded to CRT at 6 months follow-up. Multivariate logistic regression analysis including lateral-to-septal work difference, septal scar, QRS duration and QRS morphology found that only lateral-to-septal work difference and septal scar were significant predictors of CRT response (both p&lt;0.005). Using logistic regression and receiver operating characteristic (ROC) curve analysis, we found that the combined approach of these two parameters identified CRT responders with a sensitivity of 86% and a specificity of 82%. The area under the curve (AUC) for CRT response prediction was 0.85 (95% CI: 0.76–0.94) (Figure). In comparison, the AUC value for QRS duration was 0.63 (95% CI: 0.52–0.75). Furthermore, for the subgroup of patients with QRS duration 120–150 ms (n=27), the AUC value for lateral-to-septal work difference in combination with septal scar was 0.90 (95% CI: 0.78–1.00). Conclusions A multimodality approach with strain echocardiography and LGE-CMR was able to detect CRT responders with high accuracy, also in the subset of patients with intermediate QRS duration. A dysfunctional but viable septum appears to be an ideal target for CRT.

P2714Time-dependent myocardial necrosis in patients suffering from ST-elevation myocardial infarction without angiographic collateral flow visualized by cardiac magnetic resonance imaging

Abstract Background Acute complete occlusion of a coronary artery results in progressive ischemia, moving from the endocardium to the epicardium (“wavefront”). Dependent on time-to-reperfusion and collateral flow, myocardial infarction (MI) will manifest, with transmural MI portending poor prognosis. Late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) imaging can detect MI with high diagnostic accuracy. Primary percutaneous coronary intervention (PCI) is the preferred reperfusion strategy in patients with STEMI &lt;12 hours of symptom onset. Purpose We sought to visualize time-dependent necrosis in a ST-segment elevation myocardial infarction (STEMI) population by LGE-CMR. Methods STEMI patients with: single-vessel disease, complete occlusion with Thrombolysis in Myocardial Infarction (TIMI) score 0, absence of collateral flow (Rentrop score 0) and symptom onset &lt;12 hours were consecutively enrolled. By LGE-CMR, area at risk (AAR) and infarct size (IS), myocardial salvage index (MSI), transmurality index, and transmurality grade (0–50%, 51–75%, 76–100%) were determined. Results 164 patients (54±11 years, 80% male) were included. Receiver-operating-characteristic (ROC)-curve (area under the curve [AUC] = 0.81) indicating transmural necrosis revealed the best diagnostic cut-off for a symptom-to-balloon time of 121 minutes, i.e. patients with &gt;121 minutes demonstrated increased IS, transmurality index, transmurality grade (all p-values &lt;0.01), and decreased MSI (p&lt;0.001) vs. patients with symptom-to-balloon times ≤121 minutes. Conclusions In myocardial infarction with no residual antegrade, and no collateral flow, immediate reperfusion is vital. A symptom-to-balloon time of &gt;121 minutes causes a high grade of transmural necrosis. In the present, pure STEMI population, time to reperfusion to salvage myocardium was less than suggested by current guidelines.