Post Gadolinium Research Articles

Cardiovascular magnetic resonance 3D LGE imaging for atrial fibrillation ablation

Abstract Objective To assess feasibility and reliability of cardiac magnetic resonance (CMR) imaging in visualizing left atrial (LA) structural changes that patients with paroxysmal atrial fibrillation (PAF) undergo acutely and long-term post ablation. Two different ablation methods i.e pulsed filed ablation (PFA) and cryoablation were studied. Background Pulmonary vein (PV) isolation has become the cornerstone technique for catheter ablation in patients with drug-refractory atrial fibrillation (AF). At present, almost all ablation technologies are mediated by a thermal effect. Recently, pulsed field ablation (PFA) has been introduced as a new energy source. PFA is a non-thermal ablative modality in which high voltage ultra-short pulses are applied to target tissue, while preserving the extracellular matrix architecture, nerves, and microvascular structures. Few data exist showing different structural LA changes between the two methods using Three-Dimensional (3D) Late Gadolinium Enhancement (LGE) Imaging. Methods CMR imaging was performed pre-ablation, acutely (<24 h), and 3 months post-ablation in 10 patients with paroxysmal atrial fibrillation (AF) undergoing pulmonary vein (PV) isolation with PFA (n = 5) or cryoablation (n = 5). 3D LGE and T2-weighted images were analysed. We obtained two data sets of 3D whole heart LGE imaging with high resolution, 20minutes post gadolinium injection. Patients underwent two acquisitions: the conventional respiratory navigated, electrocardiographically-gated 3D fast gradient echo (1.3slice thickness, 256x256 matrix acquisition) and the image-navigated isotropic high resolution 3D LGE with Dixon water-fat separation. 3D LGE data were analysed using a dedicated (ADAS LA) software in order to produce a 3D-LA model visualization of LGE areas. Results In the acute stage, LGE volume was 50% larger after PFA vs. cryoablation (P < 0.001), and oedema on T2 imaging was significantly smaller (visual estimation) on PFA cases. LGE rings surrounding PV ostia were more homogeneous after PFA, with no sign of microvascular damage or intramural hemorrhage as compared to cryoablation cases. In the chronic stage, the majority of acute LGE had disappeared after PFA, whereas most LGE persisted after cryo-ablation. The two 3D LGE sequences used for analysis showed complete agreement in the visualization of atrial scar with superior image quality of the novel sequence. The mean acquisition time for 3D LGE imaging was 11±4minutes for the conventional fast gradient echo sequence, and 5±2minutes for the novel 3D self-image navigated LGE sequence. Conclusions CMR imaging may help in visualization and understanding of LA structural remodeling post different ablation techniques.

MYOCARDITIS, CORONARY ARTERY DISSECTION OR BOTH: A JUVENILE ENIGMA

Abstract A 26–year–old man was admitted to the Coronary Care Unit for severe, non–irradiated, oppressive anterothoracic pain. He had no relevant pathological history, but reported an episode of gastroenteritis the week before. EKG showed sinus rhythm and accelerated idioventricular rhythm phases. Blood pressure and 2D echo were normal. Inflammation indeces were negative, hsTnT reached a peak of 2026 ng/L. Despite the absence of inflammation signs, our first guess was myocarditis. Cardiac magnetic resonance (CMR) was performed: T2w–STIR images showed edema of the middle inferior wall and of the mid–basal anterior and anterolateral wall, while T1–weighted post gadolinium images showed transmural enhancement of the mid–basal anterior, antero lateral and inferior walls with a dubious origin from the sub endocardium in the anterior and anterolateral segments; LVEF was 55%. Invasive coronary angiography (ICA) was performed to rule out ischemic etiology: LAD showed a very thin lumen in its periphery and two obtuse marginal branches had an amputated appearance: it made us think of healing dissections. Then it turned out that the patient have been working out with heavy weights the day before: we therefore considered spontaneous coronary artery dissection. Such hypothesis was consistent with the absence of inflammations indices, but didn’t explain the basal and middle inferior involvement that CMR had shown. On the other hand, the angiographic finding may be consistent with peripheral vascular suffering linked to myocarditis induced inflammation. To date, we haven’t found univocal interpretation. Anti–remodeling therapy with IACE and beta blockers was administered, in addition to acetylsalicylic acid. CMR will be performed in two months and may provide further results once the edema will be reabsorbed. ICA will be repeated to make sure that distal coronary blood flow is improved. Take Home Messages Myocarditis can also occur with no signs of inflammation. In myocarditis it has been demonstrated that slower distal coronary blood flow may occur, due to the increase in peripheral vascular resistance linked to the presence of edema. In the acute phase, especially if CMR is performed very early, the large amount of edema can make the enhancement transmural, masking the site of origin of the damage.

Asymmetric Myocardial Involvement as an Early Indicator of Cardiac Dysfunction in Pediatric Dystrophinopathies: A Study on Cardiac Magnetic Resonance (CMR) Parametric Mappings.

Dystrophinopathies, such as Duchenne and Becker muscular dystrophy, frequently lead to cardiomyopathy, being its primary cause of mortality. Detecting cardiac dysfunction early is crucial, but current imaging methods lack insight into microstructural remodeling. This study aims to assess the potential of cardiac magnetic resonance (CMR) parametric mappings for early detection of myocardial involvement in dystrophinopathies and explores whether distinct involvement patterns may indicate impending dysfunction. In this prospective study, 23 dystrophinopathy patients underwent CMR with tissue mappings. To establish a basis for comparison, a control group of 173 subjects was analyzed. CMR protocols included SSFP, T2-weighted and T1-weighted sequences pre and post gadolinium, and tissue mappings for native T1 (nT1), extracellular volume (ECV), and T2 relaxation times. The difference between the left ventricular posterior wall and the interventricular septum was calculated to reveal asymmetric myocardial involvement. Significant differences in LV ejection fraction (LVEF), myocardial mass, and late gadolinium enhancement confirmed abnormalities in patients. Tissue mappings: nT1 (p < 0.001) and ECV (p = 0.002), but not T2, displayed substantial variations, suggesting sensitivity to myocardial involvement. Asymmetric myocardial involvement in nT1 (p = 0.01) and ECV (p = 0.012) between septal and LV posterior wall regions was significant. While higher mapping values didn't correlate with dysfunction, asymmetric involvement in nT1 (ρ=-0.472, p = 0.023) and ECV (ρ=-0.460, p = 0.049) exhibited a significant negative correlation with LVEF. CMR mappings show promise in early myocardial damage detection in dystrophinopathies. Although mapping values may not directly correspond to dysfunction, the negative correlation between asymmetric involvement in nT1 and ECV with LVEF suggests their potential as early biomarkers. Larger, longitudinal studies are needed for a comprehensive understanding and improved risk stratification in dystrophinopathies.

Abstract 18714: Myocardial Infarction With Non-Obstructive Coronary Artery Disease in a Young Woman - The Cardinal Role of Coronary Reactivity Testing in Unveiling the Underlying Etiology

43-year old female presented to the emergency department with substernal chest pain. She had similar symptoms years ago without obstructive CAD on coronary angiogram and was diagnosed with myocarditis. Presenting ECG revealed new anterolateral T wave inversions (Fig 1), and high-sensitivity troponins peaked at 322 ng/L consistent with NSTEMI. TTE was significant for global hypokinesis of the left ventricle with a reduced ejection fraction of 35 to 40%. Invasive coronary angiogram showed no obstructive CAD or spontaneous coronary artery dissection however there was reduced flow in the mid to distal LAD raising suspicion for endothelial and microvascular dysfunction. Contrast-enhanced cardiac MRI showed myocardial edema in the anterior and anteroseptal walls with elevated myocardial T1 and T2 values, and early enhancement post gadolinium administration showed an acute LAD territorial infarct (Fig 2). Findings were consistent with myocardial infarction with non-obstructive coronary artery disease (MINOCA). She was started on carvedilol for empiric treatment of coronary artery spasm and microvascular dysfunction, along with aspirin and atorvastatin. Losartan was added for heart failure management. Outpatient invasive coronary reactivity testing showed severe epicardial (70% vasoconstriction) and microvascular (80% decrease in coronary blood flow) endothelial dysfunction in response to acetylcholine (Fig 3 and Fig 4) as underlying etiology of recent MINOCA. CFR was normal. L-arginine (NO precursor) was added to the medical regimen. Patient has not had recurrence of chest pain or ACS at 1 year follow-up and LVEF normalized on repeat echocardiogram. This case shows the importance of cardiac MRI in confirming the diagnosis of MINOCA in patients with no obstructive CAD, and the crucial role of coronary reactivity testing in diagnosing and treating severe coronary endothelial dysfunction, which is aligned with the AHA/ACC MINOCA consensus document.

THU668 Euthyroid Graves’ Ophthalmopathy: Case Series

Abstract Disclosure: S.S. Alfadl: None. A.A. Asiri: None. A.A. Jammah: None. O. Alsagheir: None. Introduction: Graves’ ophthalmopathy is an autoimmune disorder that affects the eyes, characterized by swelling, proptosis, lid lag, inflammation and eyelid retraction. A significant proportion of cases are associated with thyrotoxicosis and positive serum TSH receptor antibody tests. Case Description: We present a case series of euthyroid Graves’ ophthalmopathy in patients with a negative TSH receptor antibody. The first case is of a 37-year-old lady who was recently diagnosed with idiopathic intracranial hypertension due to history of recurrent headaches and was found on CT brain to have an incidental empty sella syndrome and findings highly suggestive of thyroid associated orbitopathy. A dedicated MRI orbit showed bilateral mild proptosis with bilateral medial and inferior recti thickening, sparing the tendinous insertion. The involved extraocular muscles show mild peripheral high T2 signals and minimal enhancement on post gadolinium images. The enlarged extraocular muscle demonstrates diffusion restriction with low Apparent Diffusion Coefficient (ADC) value. Clinically, the patient did not exhibit any symptoms of hyperthyroidism or hypothyroidism. She did not notice any changes in her eyes’ appearance, nor any changes in vision or double vision. On examination, she had mild proptosis, no restriction of extraocular movement or provoked double vision. Consequently, she was referred to Ophthalmology for further management. Investigations included a pituitary panel which did not reveal any abnormalities and a thyroid panel which revealed that she was biochemically euthyroid with a negative TSH receptor antibody test. The second case is of a 24-year-old male who is medically free and initially visited the ophthalmology clinic complaining of double vision, without any additional ophthalmic complaints. He was subsequently referred to our care to rule out thyroid eye disease. Clinically, the patient had no indications of thyroid dysfunction. Upon examination, he exhibited severe right eye proptosis with dystopia and early left eye proptosis. CT orbit showed swelling of the right-sided superior rectus, medial rectus, lateral rectus and left-sided superior rectus muscles. The left-sided superior rectus muscle was abutting the optic nerve. Nevertheless, all tendons were spared. Biochemically, he was euthyroid with unremarkable laboratory results. Conclusion: These findings provide insight into the clinical presentation of euthyroid Graves’ ophthalmopathy in patients without thyrotoxicosis or detectable circulating levels of TSH receptor antibodies. Thus, suggesting that thyroid ophthalmopathy might present earlier than Graves’ disease and even earlier than the presence of TSH receptor antibodies. We conclude that a high index of suspicion and proper follow up is recommended in similar patients for the development of Graves’s disease. Presentation: Thursday, June 15, 2023

Diagnosis of pituitary abscess and treatment via transsphenoidal surgery: experience from 15 cases

ObjectivePituitary abscess is an often misdiagnosed, rare clinical disorder. To improve diagnostic accuracy and the efficacy of surgical and antibiotic therapy for patients with pituitary abscess, herein, we retrospectively reviewed 15 patients who presented with pituitary abscesses from 2005 to 2022. DesignRetrospective study. PatientsFifteen patients underwent transsphenoidal surgery and received antibiotic treatment. MeasurementsComplete details regarding medical history, clinical manifestations, laboratory examinations, imaging studies, and treatment strategies were obtained for all patients. ResultsMost patients presented with hypopituitarism and headaches, while some presented with fever, visual disturbances, and diabetes insipidus (DI). Abscesses showed significant annular enhancement post gadolinium injection. In most patients, pituitary abscess can be cured via microscopic or endoscopic drainage of the abscess followed by antibiotic treatment. Complete cure of pituitary abscess was observed in nine patients, with six cases of prolonged hypopituitarism and only one case of recurrence. Long-term hormone replacement therapy was effective in the postoperative management of hypopituitarism. ConclusionsThe typical manifestations of pituitary abscess include hypopituitarism and headaches; the presence of an enhanced ring at the edge of the mass on contrast-enhanced magnetic resonance images (MRI) is highly suggestive of pituitary abscess. We recommend antibiotic treatment for 4–6 weeks postoperatively, based on the results of bacterial cultures or metagenomic next-generation sequencing (mNGS).

Left atrium surface mesh reconstruction from cardiac MRI

Abstract Funding Acknowledgements Type of funding sources: None. Background The strive towards personalised medicine is universal across all aspects of healthcare. In the management of atrial fibrillation (AF), this can take the form of shape analysis tools to predict an individual’s outcome from catheter ablation (1–3), or electrophysiological simulations to plan an ablation strategy (4–6). Fundamental to their application is our ability to derive accurate three-dimensional (3D) anatomical models of a patient’s left atrial geometry from cross-sectional imaging. MRI is widely utilised in this regard due to its excellent tissue characterisation. However, constructing surface meshes can be challenging given its relatively sparse two-dimensional (2D) image planes. A particular challenge exists in producing a mesh that balances concordance with left atrium segmentation and smoothing terms to eliminate sharp edges and artifact from the contouring process. Objective Here, we describe a novel method for left atrium surface mesh reconstruction from MRI contours. Methods Cardiac MRI was performed on ten patients with paroxysmal or persistent AF, on a 3T clinical MR scanner using phased-array receiver coils. Image sequences included respiratory and ECG-gated 15-minute post contrast late gadolinium enhancement, with a 1.3mm slice thickness and in-plane resolution of 0.66×0.66mm2. Seven individuals were in sinus rhythm, and three in AF at the time of MRI. A single, custom, graphical interface tool implemented in Matlab R2014a enabled 3D mesh reconstruction from 2D MRI slices (7,8). Endocardial surfaces of the left atrium were manually segmented by an experienced clinician, with the pulmonary veins and left atrial appendage excluded at their ostia (Figure 1A). Our tool produced an initial sparse representation with vertices equally spaced along the contours (Figure 1B). Attractor points were defined along the contours, with subdivision and Laplacian smoothing applied to the mesh. This was balanced with a deformation step, which iteratively pulled the mesh towards the attractor points (Figure 1C), resulting in its final shape (Figure 1D). Results Reconstruction performance was evaluated by measuring the distance between heart contours and the reconstructed 3D surface for each case, producing the value for average misalignment 0.71 ± 0.58mm, which compares favourably to the in-plane resolution. Conclusions Our approach offers a highly accurate method for producing 3D anatomical models of the left atrium from MRI, which is fully automated following segmentation through an interactive graphical interface. The iterative optimisation between attractor-based deformation towards the original contours and the Laplacian smoothing enables us to create smooth geometries which remain true to their segmentations. Furthermore, our approach does not require the use of a template mesh, which can result in final geometries being biased towards the template.

Delayed post gadolinium MRI descriptors for Meniere's disease: a systematic review and meta-analysis.

Delayed post-gadolinium magnetic resonance imaging (MRI) detects changes of endolymphatic hydrops (EH) within the inner ear in Meniere's disease (MD). A systematic review with meta-analysis was conducted to summarise the diagnostic performance of MRI descriptors across the range of MD clinical classifications. Case-controlled studies documenting the diagnostic performance of MRI descriptors in distinguishing MD ears from asymptomatic ears or ears with other audio-vestibular conditions were identified (MEDLINE, EMBASE, Web of Science, Scopus databases: updated 17/2/2022). Methodological quality was evaluated with Quality Assessment of Diagnostic Accuracy Studies version 2. Results were pooled using a bivariate random-effects model for evaluation of sensitivity, specificity and diagnostic odds ratio (DOR). Meta-regression evaluated sources of heterogeneity, and subgroup analysis for individual clinical classifications was performed. The meta-analysis included 66 unique studies and 3073 ears with MD (mean age 40.2-67.2years), evaluating 11 MRI descriptors. The combination of increased perilymphatic enhancement (PLE) and EH (3 studies, 122 MD ears) achieved the highest sensitivity (87% (95% CI: 79.92%)) whilst maintaining high specificity (91% (95% CI: 85.95%)). The diagnostic performance of "high grade cochlear EH" and "any EH" descriptors did not significantly differ between monosymptomatic cochlear MD and the latest reference standard for definite MD (p = 0.3; p = 0.09). Potential sources of bias were case-controlled design, unblinded observers and variable reference standard, whilst differing MRI techniques introduced heterogeneity. The combination of increased PLE and EH optimised sensitivity and specificity for MD, whilst some MRI descriptors also performed well in diagnosing monosymptomatic cochlear MD. • A meta-analysis of delayed post-gadolinium magnetic resonance imaging (MRI) for the diagnosis of Meniere's disease is reported for the first time and comprised 66 studies (3073 ears). • Increased enhancement of the perilymphatic space of the inner ear is shown to be a key MRI feature for the diagnosis of Meniere's disease. • MRI diagnosis of Meniere's disease can be usefully applied across a range of clinical classifications including patients with cochlear symptoms alone.

MRI-derived radiomics to guide post-operative management of glioblastoma: Implication for personalized radiation treatment volume delineation.

The glioblastoma's bad prognosis is primarily due to intra-tumor heterogeneity, demonstrated from several studies that collected molecular biology, cytogenetic data and more recently radiomic features for a better prognostic stratification. The GLIFA project (GLIoblastoma Feature Analysis) is a multicentric project planned to investigate the role of radiomic analysis in GB management, to verify if radiomic features in the tissue around the resection cavity may guide the radiation target volume delineation. We retrospectively analyze from three centers radiomic features extracted from 90 patients with total or near total resection, who completed the standard adjuvant treatment and for whom we had post-operative images available for features extraction. The Manual segmentation was performed on post gadolinium T1w MRI sequence by 2 radiation oncologists and reviewed by a neuroradiologist, both with at least 10 years of experience. The Regions of interest (ROI) considered for the analysis were: the surgical cavity ± post-surgical residual mass (CTV_cavity); the CTV a margin of 1.5 cm added to CTV_cavity and the volume resulting from subtracting the CTV_cavity from the CTV was defined as CTV_Ring. Radiomic analysis and modeling were conducted in RStudio. Z-score normalization was applied to each radiomic feature. A radiomic model was generated using features extracted from the Ring to perform a binary classification and predict the PFS at 6 months. A 3-fold cross-validation repeated five times was implemented for internal validation of the model. Two-hundred and seventy ROIs were contoured. The proposed radiomic model was given by the best fitting logistic regression model, and included the following 3 features: F_cm_merged.contrast, F_cm_merged.info.corr.2, F_rlm_merged.rlnu. A good agreement between model predicted probabilities and observed outcome probabilities was obtained (p-value of 0.49 by Hosmer and Lemeshow statistical test). The ROC curve of the model reported an AUC of 0.78 (95% CI: 0.68-0.88). This is the first hypothesis-generating study which applies a radiomic analysis focusing on healthy tissue ring around the surgical cavity on post-operative MRI. This study provides a preliminary model for a decision support tool for a customization of the radiation target volume in GB patients in order to achieve a margin reduction strategy.

Focal Infarction of the Falciform Ligament: Case Series

Background: The purpose of this article is to review the clinical presentation and imaging findings of a case of focal infarction of the falciform ligament. Methods: Patient’s history and diagnostic imaging were retrospectively reviewed. These findings were compared with cases of falciform ligament torsion and/or infraction reported in the literature. Results: To our knowledge, there are less than twenty cases of falciform ligament torsion and/or infraction reported in the literature [2,4]. Our patient’s presentation of right upper quadrant/epigastric pain was consistent with reported symptoms. While imaging findings using ultrasound have been reported, our case did not reveal any abnormalities on ultrasound. CT findings in our case were similar to findings in the literature and revealed significant fat stranding and inflammatory changes along the falciform ligament. Our diagnosis was also supported using MRI which revealed hyperintensitysurrounding the falciform ligament on T1 and T2/SPAIR as well as rim enhancement on T1 weighted post gadolinium imaging. MRI findings have only been described in one other case in the literature [3]. Conclusion: Imaging findings of falciform ligament torsion and/or infarction have been described in the literature using ultrasound, CT and MRI [3]. In our case, the diagnosis of focal infarction of the falciform ligament was supported by CT and MRI. It is important for radiologists to be aware of this diagnosis as there are few reported cases in the literature and the clinical presentation is often non-specific.

P02.11.B An hypothesis generating study of MRI-Derived Radiomics on tumor and microenvironment tissue heterogeneity to guide post-operative management of glioblastoma: toward personalized radiation treatment volume delineation

Abstract Background The glioblastoma’s bad prognosis is primarily due to intra-tumor heterogeneity, demonstrated from several studies that collected molecular biology, cytogenetic data and more recently radiomic features for a better prognostic stratification.The GLIFA project (GLIoblastoma Feature Analysis) is a multicentric project planned to investigated the role of radiomic analysis in GBM management, to verify if radiomic features in the tissue around the resection cavity which may guide the radiation target volume delineation. Material and Methods We retrospectively analyze from three centers radiomic features extracted from 90 patients with total or near total resection, who completed the standard adjuvant treatment and for whom we had post-operative images available for features extraction.The Manual segmentation was performed on post gadolinium T1w MRI sequence by 2 radiation oncologist reviewed by a neuroradiologist, both with at least 10 years of experience. The Region of interest (ROI) considered for the analysis were: the surgical cavity +/- post-surgical residual mass (CTV_cavity); the CTV a margin of 1.5 cm added to CTV_cavity and the volume resulting from subtracting the CTV_cavity from the CTV was defined as CTV_Ring. Radiomic analysis and modelling were conducted in RStudio. Z-score normalization was applied to each radiomic feature. A radiomic model was generated using the 226 features extracted from the Ring to perform a binary classification and predict the PFS at 6 months (statistical, morphological and textural features). A 3-fold cross-validation repeated five times was implemented for internal validation of the model. Results Two-hundred and seventy ROIs were contoured. The proposed radiomic model was given by the best fitting logistic regression model, and included the following 3 features: F_cm_merged.contrast, F_cm_merged.info.corr.2, F_rlm_merged.rlnu. A good agreement between model predicted probabilities and observed outcome probabilities was obtained (p-value of 0.49 by Hosmer and Lemeshow statistical test). The ROC curve of the model reported an AUC of 0.78 (95% CI: 0.68 - 0.88). Conclusion This is the first hypothesis-generating study who applies a radiomic analysis focusing on healthy tissue ring around the surgical cavity on post-operative MRI. This study provides a preliminary model for a decision support tool for a customization of the radiation target volume in GBM patients in order to achieve a margin reduction strategy.

Intraventricular Pilocytic Astrocytoma: A Single Centre Experience.

Intraventricular pilocytic astrocytomas are a rare occurrence, accounting for approximately 4% -15.6% of all pilocytic astrocytomas .The aim of the study was to describe the radiology, surgical management and outcome in 15 patients with histopathologically proven intraventricular pilocytic astrocytoma(IVPA). To study the clinical presentation radiology and operative challenges in rare intra ventricular pilocytic astrocytomas. Between January 2010 and August 2018, 15 patients with histopathologically proven IVPA were identified. The radiological images were obtained from PACS. Patient and surgical details were obtained from the computerized discharge summary, OT records and operative notes, whereas follow up was obtained from the record section. Headache with progressive loss of vision was the most common presentation. Duration of symptoms varied from 4 months to 2 years (mean 9. 88 months). Except one patient, all patients with preoperative CT scan revealed calcifications in the lesion, with extensive calcification in 3 patients. All the tumors were predominantly hypointense on T1WI and iso to hyperintense on T2WI. Lesion in all patients showed heterogenous contrast enhancement on post gadolinium images. Mean blood loss in the series was 1969 ml (range 250 ml- 4500 ml).There was one death in this series due to meningitis and septic shock. IVPAs are rare tumors and are difficult to diagnose in the preoperative period based on the radiologic profile alone. These tumors can be extremely vascular with potential for massive blood loss. These tumors can be associated with extensive calcification and the calcified tumors have less bleeding as expected.

Using magnetic resonance imaging to map the hidden burden of muscle involvement in systemic sclerosis

BackgroundSkeletal muscle can be directly affected by systemic sclerosis (SSc); however, a significant burden of SSc-associated myopathy is undetected because clinical parameters such as weakness and creatine kinase (CK) are unreliable biomarkers of muscle involvement. This study presents qualitative and quantitative magnetic resonance imaging (MRI) findings that quantify the prevalence of myopathy and evaluate any association between skeletal and cardiac muscle involvement in SSc.MethodsThirty-two patients with SSc who fulfilled the 2013 American College of Rheumatology/European League Against Rheumatism classification criteria underwent skeletal muscle MRI in addition to cardiac MRI. Skeletal muscles were independently assessed by two musculoskeletal radiologists for evidence of oedema, fatty infiltration and atrophy. Skeletal muscle T2 mapping times and percentage fat fraction were calculated. Linear regression analysis was used to evaluate the clinical and myocardial associations with skeletal muscle oedema and fatty infiltration. Cardiac MRI was performed using post gadolinium contrast imaging and parametric mapping techniques to assess focal and diffuse myocardial fibrosis.ResultsThirteen participants (40.6%) had MRI evidence of skeletal muscle oedema. Five (15.6%) participants had fatty infiltration. There was no association between skeletal muscle oedema and muscle strength, creatine kinase, inflammatory markers or fibroinflammatory myocardial disease. Patients with skeletal muscle oedema had higher T2-mapping times; there was a significant association between subjective assessments of muscle oedema and T2-mapping time (coef 2.46, p = 0.02) and percentage fat fraction (coef 3.41, p = 0.02). Diffuse myocardial fibrosis was a near-universal finding, and one third of patients had focal myocardial fibrosis. There was no association between skeletal myopathy detected by MRI and burden of myocardial disease.ConclusionsMRI is a sensitive measure of muscle oedema and systematic assessment of SSc patients using MRI shows that myopathy is highly prevalent, even in patients without symptoms or other signs of muscle involvement. Similarly, cardiac fibrosis is highly prevalent but occurs independently of skeletal muscle changes. These results indicate that novel quantitative MRI techniques may be useful for assessing sub-clinical skeletal muscle disease in SSc.

V14-03 TRANSURETHRAL WATER VAPOR ABLATION (STEAM) TO TREAT LOCALIZED PROSTATE CANCER (INVESTIGATIONAL USE ONLY)

You have accessJournal of UrologyProstate Oncology II & Testis Oncology & Misc. Oncology (V14)1 Sep 2021V14-03 TRANSURETHRAL WATER VAPOR ABLATION (STEAM) TO TREAT LOCALIZED PROSTATE CANCER (INVESTIGATIONAL USE ONLY) Christopher Dixon, and Christopher Warlick Christopher DixonChristopher Dixon More articles by this author , and Christopher WarlickChristopher Warlick More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002111.03AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Convective water vapor is a unique technology that uses the thermal energy of water vapor (steam) to ablate tissue. The objective was in vivo validation of Transurethral Vapor Ablation (TUVA) in men with clinically significant localized prostate cancer by; Group 1 - TUVA/RRP assessed by immediate whole mount sectioning, Group 2 - TUVA assessed by pre/post treatment MRI in an early feasibility trial and Both Groups by intraoperative real-time ultrasound and AE assessment. METHODS: A tabletop generator and a transurethral endoscopic delivery device, along with real-time TRUS, were used to direct water vapor into any anatomic zone of the prostate to ablate malignant prostate tissue. The procedure technique currently used, including the endoscopic and real-time ultrasound monitoring of needle deployment, advancement and vapor delivery is demonstrated. To evaluate the convective principles of TUVA, real-time ultrasound patterns of vapor delivery and 7-day post treatment gadolinium MRI images were studied. Ablation effectiveness was assessed in two independent groups. In Group 1 by whole mount sectioning immediately following TUVA / radical prostatectomy. In Group 2 by assessing pre- and 7-day post TUVA MRI nonenhancement patterns as well as PIRADSv2 resolution. Immediate safety was assessed by intraoperative inspection, gross examination of the prostate (Group 1) and immediate post op adverse events along with 7-day MRI’s (Group 2). RESULTS: Real-time ultrasound vapor patterns confirmed convective spread within the zonal anatomy and boundaries of the prostate. Real-time ultrasound during treatment demonstrated the convective principles and the ability to “see” the treatment. Collectively, whole mount sectioning along with the non-enhancing areas seen on MRI’s at 7-days demonstrated ablation to ALL anatomic zones and boundaries consistent with the unique ablation capabilities of convection. In Group 2, after one treatment session, 14/17 PIRADSv2 lesions ≥3 were no longer visible within the ablation zone on 7-day MRI. There were no serious adverse events intraoperatively or within one week of the treatment. CONCLUSIONS: Transurethral delivery of water vapor thermal energy can effectively ablate any zone of the prostate from apex to base, anterior to posterior, and laterally to the prostatic “capsule”. Early feasibility data using this investigational device are favorable. Source of Funding: Francis Medical, Maple Grove, MN © 2021 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 206Issue Supplement 3September 2021Page: e1165-e1166 Advertisement Copyright & Permissions© 2021 by American Urological Association Education and Research, Inc.MetricsAuthor Information Christopher Dixon More articles by this author Christopher Warlick More articles by this author Expand All Advertisement Loading ...

Repeat and single dose administration of gadodiamide to rats to investigate concentration and location of gadolinium and the cell ultrastructure

Gadolinium based contrast agents (GBCA) are used to image patients using magnetic resonance (MR) imaging. In recent years, there has been controversy around gadolinium retention after GBCA administration. We sought to evaluate the potential toxicity of gadolinium in the rat brain up to 1-year after repeated gadodiamide dosing and tissue retention kinetics after a single administration. Histopathological and ultrastructural transmission electron microscopy (TEM) analysis revealed no findings in rats administered a cumulative dose of 12 mmol/kg. TEM-energy dispersive X-ray spectroscopy (TEM-EDS) localization of gadolinium in the deep cerebellar nuclei showed ~ 100 nm electron-dense foci in the basal lamina of the vasculature. Laser ablation-ICP-MS (LA-ICP-MS) showed diffuse gadolinium throughout the brain but concentrated in perivascular foci of the DCN and globus pallidus with no observable tissue injury or ultrastructural changes. A single dose of gadodiamide (0.6 mmol/kg) resulted in rapid cerebrospinal fluid (CSF) and blood clearance. Twenty-weeks post administration gadolinium concentrations in brain regions was reduced by 16–72-fold and in the kidney (210-fold), testes (194-fold) skin (44-fold), liver (42-fold), femur (6-fold) and lung (64-fold). Our findings suggest that gadolinium does not lead to histopathological or ultrastructural changes in the brain and demonstrate in detail the kinetics of a human equivalent dose over time in a pre-clinical model.

Bright-blood and dark-blood phase sensitive inversion recovery late gadolinium enhancement and T1 and T2 maps in a single free-breathing scan: an all-in-one approach

BackgroundQuantitative cardiovascular magnetic resonance (CMR) T1 and T2 mapping are used to detect diffuse disease such as myocardial fibrosis or edema. However, post gadolinium contrast mapping often lacks visual contrast needed for assessment of focal scar. On the other hand, late gadolinium enhancement (LGE) CMR which nulls the normal myocardium has excellent contrast between focal scar and normal myocardium but has poor ability to detect global disease. The objective of this work is to provide a calculated bright-blood (BB) and dark-blood (DB) LGE based on simultaneous acquisition of T1 and T2 maps, so that both diffuse and focal disease may be assessed within a single multi-parametric acquisition.MethodsThe prototype saturation recovery-based SASHA T1 mapping may be modified to jointly calculate T1 and T2 maps (known as multi-parametric SASHA) by acquiring additional saturation recovery (SR) images with both SR and T2 preparations. The synthetic BB phase sensitive inversion recovery (PSIR) LGE may be calculated from the post-contrast T1, and the DB PSIR LGE may be calculated from the post-contrast joint T1 and T2 maps. Multi-parametric SASHA maps were acquired free-breathing (45 heartbeats). Protocols were designed to use the same spatial resolution and achieve similar signal-to-noise ratio (SNR) as conventional motion corrected (MOCO) PSIR. The calculated BB and DB LGE were compared with separate free breathing (FB) BB and DB MOCO PSIR acquisitions requiring 16 and 32 heart beats, respectively. One slice with myocardial infarction (MI) was acquired with all protocols within 4 min.ResultsMultiparametric T1 and T2 maps and calculated BB and DB PSIR LGE images were acquired for patients with subendocardial chronic MI (n = 10), acute MI (n = 3), and myocarditis (n = 1). The contrast-to-noise (CNR) between scar (MI and myocarditis) and remote was 26.6 ± 7.7 and 20.2 ± 7.4 for BB and DB PSIR LGE, and 31.3 ± 10.6 and 21.8 ± 7.6 for calculated BB and DB PSIR LGE, respectively. The CNR between scar and the left ventricualr blood pool was 5.2 ± 6.5 and 29.7 ± 9.4 for conventional BB and DB PSIR LGE, and 6.5 ± 6.0 and 38.6 ± 11.6 for calculated BB and DB PSIR LGE, respectively.ConclusionsA single free-breathing acquisition using multi-parametric SASHA provides T1 and T2 maps and calculated BB and DB PSIR LGE images for comprehensive tissue characterization.

MRI characterization of early CNS transport kinetics post intrathecal gadolinium injection: Trends of subarachnoid and parenchymal distribution in healthy volunteers

PurposeTo quantify CSF transport kinetics and brain glymphatic distribution using MRI following intrathecal injection of gadolinium contrast in healthy adults. Subjects and methodsEight completely healthy volunteer subjects underwent intrathecal injection of gadolinium via image guided lumbar puncture and serial MRI's at six subsequent time points up to 11 h post-injection. Rate of enhancement and deposition were calculated for various regions and lobes of the brain. ResultsNormalized cranial data revealed that gadolinium in the intracranial CSF spaces peaked within 1–3 h and started to decrease at 7 h. In some regions of the brain parenchyma, such as the cerebral cortex and white matter, enhancement was increasing after 11 h. Differential rates of uptake between the parietal and frontal (p = 0.0003), cingulate (p = 0.002) and temporal (p = 0.018) lobes were shown as well as a several fold change between various cortical regions. Lastly, a linear regression comparing laterality between 35 cortical regions yielded (R2 = 0.90, p < 0.001) with a slope of 1.01 showing symmetry in uptake. ConclusionsGadolinium enhancement after lumbar intrathecal injection demonstrated differential CSF flow and brain parenchymal penetration, which illustrated the distributory function of the glymphatic system.

NIMG-71. DETECTION OF CYSTIC GLIOBLASTOMA FROM MAGNETIC RESONANCE IMAGING USING DEEP LEARNING TECHNIQUES

Abstract Glioblastoma (GBM) is the most aggressive primary brain tumor with an average survival of 15 months with standard of care treatment. GBM patients typically present with necrosis surrounded by enhancement on T1-weighted post gadolinium magnetic resonance imaging (T1gd MRI), however some patients present with a significant cystic component. Cysts are caused by different underlying biological mechanisms to necrosis and are important to identify for future clinical investigations. These cystic components can be manually identified through MRI but this process can be time consuming for large patient cohorts. Over the last two decades, our lab has collected serial MRI data of brain tumor patients. With over 70,000 images now in the database and that number increasing daily, it is clear that we have a unique resource for clinical investigation and a need to automate this process. To this end, the aim of this work was to develop and assess the performance of a convolution neural network (CNN) model for automatic detection of cystic GBMs. In this retrospective IRB-approved work, we collected pretreatment MRIs of a patient cohort consisting of 85 patients with a significant cystic component at presentation along with 400 non-cystic GBM, both identified manually through MRI. Image slices with a view of the cystic component were used as positive samples for training. Data were randomly split into training, validation, and test sets using a 70:15:15 ratio. The proportion of positive to negative cases was comparable between sets. Prior to training, we used image augmentation techniques to compensate for the class imbalance in our data. Our results showed that deep learning networks can automatically detect cystic GBMs on MRIs with high accuracy and thus illustrates the potential use of this technique in clinically relevant settings.

P.318MRI evaluation of skeletal muscle in the deltaE50-MD dog model of Duchenne muscular dystrophy

There is currently no cure for the fatal X-linked disorder Duchenne muscular dystrophy (DMD) and clinically-applicable translational trials continue to rely heavily on use of animal models. The Royal Veterinary College has a unique colony of dystrophin deficient dogs: the deltaE50-MD dog model. Magnetic Resonance Imaging (MRI) is a valuable non-invasive technique for monitoring the progression of the disease in human DMD patients. The aim was to determine if the deltaE50-MD dog has a skeletal muscle MRI phenotype that resembles that of DMD boys and to determine MRI differences of skeletal muscles in dystrophic and wildtype dogs. MRI was conducted in 15 deltaE50-MD dogs and 10 age-matched littermate wildtype male dogs under general anaesthetic, every 12 weeks from 3 months to 18 months of age. Up to 7 pelvic limb muscles and 4 lumbar muscles were assessed bilaterally in each dog. Four MRI biomarkers assessed were muscle volume normalised to femur length, T2 map signal intensity (SI), T1w to post gadolinium T1w SI ratio and muscle heterogeneity. The mean was calculated for each pair of muscles for all MRI biomarkers. Mixed model analyses (SPSS) were used to examine differences between groups at different ages. Muscle volumes were significantly smaller (p<0.001) in affected dogs when compared to wildtype dogs in all examined muscles, apart from the cranial sartorius. T2 map SI (p<0.001) and muscle heterogeneity (p<0.05) were significantly higher in affected dogs when compared to wildtype dogs. Affected dogs had significantly increased post gadolinium T1w SI in all muscles (p<0.05), apart from the cranial sartorius muscle, when compared to wildtype dogs. The most useful MRI biomarkers found in this study were muscle volume normalised to femur length and T2 map SI. Both of these biomarkers were able to show differences between groups and track changes longitudinally. These MRI biomarkers will be useful to determine efficacy of therapeutic clinical trials in the colony.

The Effect of Tumor Volume Changes on the Boost-Volume Coverage in Glioblastoma Patients

Radiotherapy is one of the main treatment modalities in the multimodal therapy of glioblastoma patients. The ongoing NRG-BN001 trial (NCT02179086) is evaluating whether boosting a sub-volume with photons or protons improves overall survival as compared to standard-dose photon irradiation. We hypothesize that anatomical changes during irradiation may affect the dose coverage and that these changes may have a greater impact on proton treatment plans compared to photon treatment plans. For 24 glioblastoma patients, the MRI was repeated half way during radiation treatment. Three patients had a gross total resection (GTR), four patients underwent a biopsy, and 17 patients had a subtotal resection (STR). These patients were treated according to the EORTC-ACROP guideline. A simulated photon and proton treatment plan (intensity modulated proton therapy; IMPT) according to the NRG-BN001 trial were made retrospectively. In this trial, patients in the experimental arm receive a dose of 46Gy/30fr on the T2w/FLAIR abnormalities and 75Gy/30fr on the planning target boost volume (PTV-7500). The PTV-7500 was defined as the resection cavity and/or contrast enhancing lesion on the T1w post gadolinium sequence of the MRI plus a margin of 5 mm (CTV) plus a 4 mm expansion in all dimensions. The trial constraints states that at least 95% of the PTV-7500 should receive 75Gy. To analyze the effect of anatomical changes during treatment on the dose coverage, we evaluated the planned dose distribution (based on the planning MRI) on the delineated PTV-7500 of the repeated MRI. The median time interval between the two MRIs was 25.5 days (range 15 – 36 days). Between the two scans, the PTV-7500 volume changed with a median of -0.1cc. However, we observed a wide range of -52.8 to +52.2cc. For the photon treatment plans we observed that 83% (n=20) of the patients showed a decline in PTV-7500 coverage (corresponding with a median decline of 6.5% and 8.3cc). The quartile of patients (n=6) with the largest PTV-7500 increase showed a 10% reduction in dose coverage (corresponding with a median volume of 33.2cc). There was no significant difference in coverage changes of the boost volume between the GTR, biopsy only and STR patients (p=0.632). The evaluation of the IMPT plans is ongoing and will be presented during the conference. During fractionated radiation treatment for glioblastoma patients we observed large target volumetric changes in the boost volume half way during treatment. These target volume changes may lead to substantial declines in dose coverage when patients are treated according to dose-escalation protocol boosting specific sub-volumes. Thus, an important subset of glioblastoma patients may benefit from an MRI guided dose escalation strategy.