Preprocedural Magnetic Resonance Imaging Research Articles

Epicardial Atrial Fat at Cardiac Magnetic Resonance Imaging and AF Recurrence after Transcatheter Ablation.

The relationship between epicardial adipose tissue (EAT) and atrial fibrillation (AF) has gained interest in recent years. The previous literature on the topic presents great heterogeneity, focusing especially on computed tomography imaging. The aim of the present study is to determine whether an increased volume of left atrial (LA) EAT evaluated at routine pre-procedural cardiac magnetic resonance imaging (MRI) relates to AF recurrences after catheter ablation. A total of 50 patients undergoing AF cryoballoon ablation and pre-procedural cardiac MRI allowing quantification of LA EAT were enrolled. In one patient, the segmentation of LA EAT could not be achieved. After a median follow-up of 16.0 months, AF recurrences occurred in 17 patients (34%). The absolute volume of EAT was not different in patients with and without AF recurrences (10.35 mL vs. 10.29 mL; p-value = 0.963), whereas the volume of EAT indexed on the LA volume (EATi) was lower, albeit non-statistically significant, in patients free from arrhythmias (12.77% vs. 14.06%; p-value = 0.467). The receiver operating characteristic curve testing the ability of LA EATi to predict AF recurrence after catheter ablation showed sub-optimal performance (AUC: 0.588). The finest identified cut-off of LA EATi was 10.65%, achieving a sensitivity of 0.5, a specificity of 0.82, a positive predictive value of 0.59 and a negative predictive value of 0.76. Patients with values of LA EATi lower than 10.65% showed greater survival, free from arrhythmias, than patients with values above this cut-off (84% vs. 48%; p-value = 0.04). In conclusion, EAT volume indexed on the LA volume evaluated at cardiac MRI emerges as a possible independent predictor of arrhythmia recurrence after AF cryoballoon ablation. Nevertheless, prospective studies are needed to confirm this finding and eventually sustain routine EAT evaluation in the management of patients undergoing AF catheter ablation.

Evaluation of Uterine Fibroid Vascularity Using Contrast-Enhanced Ultrasound in Comparison with Contrast-Enhanced Magnetic Resonance Imaging

ObjectiveTo assess uterine fibroid vascularity using contrast-enhanced ultrasound (CEUS) comparing these findings with magnetic resonance imaging (MRI). MethodsForty women diagnosed with symptomatic uterine fibroids scheduled for uterine artery embolization (UAE) were enrolled in this IRB-approved study. Subjects underwent CEUS examination prior to UAE using an Aplio i800 scanner (Canon Medical Systems, Tustin, CA, USA) with curvilinear array (8C1). CEUS was performed using 2.0ml of the ultrasound contrast agent, Lumason (Bracco, Milan, Italy) administered intravenously. Digital CEUS clips were acquired, randomized off-line and fibroids were characterized hyper- or hypovascular. MRI was used as reference standard for fibroid vascularity and compared to CEUS. Results were analyzed using McNemar's test. ResultsForty subjects were enrolled in the trial. One patient did not proceed with the UAE procedure and one patient refused pre-procedure MRI due to claustrophobia. Therefore, 38 subjects underwent CEUS and MRI examinations prior to UAE. Hypervascular fibroids were seen on MRI and CEUS in 24 and 26 subjects, respectively. Hypovascular fibroids were seen with MRI and CEUS in 14 and 12 subjects, respectively. Fibroids characterized as hypovascular in two subjects by MRI were characterized as hypervascular by CEUS. CEUS and MRI findings were similar in 36/38 subjects corresponding to an accuracy of 95% (p = 0.62). ConclusionCEUS can accurately assess uterine fibroid vascularity serving as a potential alternative to MRI to determine vascularity of uterine fibroids.

CT-guided lumbar facet cyst rupture and corticosteroid injection: technique, approach, and procedural and clinical success rates.

To evaluate success rates of computed tomography (CT)-guided lumbar facet synovial cyst (LFC) rupture. We retrospectively reviewed all LFC ruptures performed by a single musculoskeletal radiologist with > 10years of experience, using posterior facet approach and/or direct puncture by ipsilateral/contralateral interlaminar, or transforaminal approach. All patients also received a corticosteroid injection. Rupture rates were calculated, and clinical success rate was determined through medical record review. Pre-procedure magnetic resonance imaging (MRI) images and CT procedure images were also reviewed for LFC and facet joint imaging features that may predict rupture. There were 37 patients, 17 (46%) female and 20 (54%) male, ages 62 ± 12 (range 39-87) years. Thirty-four (92%) of LFC were successfully ruptured, 17 (50%) by facet approach and 17 (50%) by direct cyst puncture. At least one direct puncture approach was possible in 35 (95%) patients. No MRI or CT LFC or facet joint features predicted cyst rupture. Thirty-one (91%) of patients reported immediate pain relief, and 19 (53%) did not have further intervention for LFC-related pain. Sixteen (84%) of these patients remained pain-free for an average follow-up time period of 28months. Fourteen (39%) of patients required surgical intervention. There were no complications. Our systematic approach to CT-guided LFC rupture is safe and has high technical and clinical success rates similar to prior studies. Since there are no definitive imaging features that determine rupture success, this procedure can almost always be attempted as a first-line treatment for LFC.

Surgical and transcatheter pulmonary valve replacement in patients with repaired tetralogy of Fallot: cardiac magnetic resonance imaging characteristics and morphology of right ventricular outflow tract.

Pulmonary valve replacement is recommended in patients with repaired tetralogy of Fallot based on cardiac magnetic resonance imaging (MRI) criteria. This procedure is performed by surgical or transcatheter approaches. We aimed to investigate the differences in preprocedural MRI characteristics (volume, function, strain) and morphology of the right ventricular outflow tract and branch pulmonary arteries in patients for whom surgical or transcatheter pulmonary valve replacementwas planned. Cardiac MRI of 166 patients with tetralogy of Fallot were analyzed. Of these, 36 patients for whompulmonary valve replacement was plannedwere included. Magnetic resonance imaging characteristics, right ventricular outflow tract morphology, branch pulmonary artery flow distribution and diameter were compared between surgical and transcatheter groups. Spearman correlation and Kruskal-Wallis tests were performed. Circumferential and radial MRI strain for the right ventricle were lower in thesurgical group (P=0.045and P=0.046, respectively). The diameter of the left pulmonary artery was significantly lower (P=0.021) and branch pulmonary artery flow and diameter ratio were higher (P=0.044and P = 0.002, respectively) in the transcatheter group. There was a significant correlation between right ventricular outflow tract morphology and right ventricular end-diastolic volume indexand global circumferential and radial MRI strain (P=0.046, P=0.046and P= 0.049, respectively). Preprocedural MRI strain, right-to-left pulmonary artery flow, diameter ratio and morphological features of the right ventricular outflow tract were significantly different betweenthe two groups. A transcatheter approach may be recommended for patients with branch pulmonary artery stenosis, since both pulmonary valve replacement and branch pulmonary artery stenting can be performed in the same session.

‘Scanxiety’: Content analysis of pre-MRI patient experience on Instagram

IntroductionDistress and anxiety are commonly reported during the Magnetic Resonance Imaging (MRI) experience with prior studies suggesting the pre-MRI period is a time of heightened distress. There is a paucity of literature exploring preprocedural distress and anxiety, in particular qualitative research analysing patient experience. Instagram is rapidly becoming an important social media platform though which to conduct health research. A gradually increasing number of studies have examined social media to gain insight into patient experience within medical radiation science (MRS). This study is considered as the first to explore patient experience of MRI using Instagram as a data source. MethodsThis study investigated the patient experience during the pre-MRI period by performing a content analysis on open-source Instagram posts. Ethical approval for the study was sought and approved by the Charles Sturt University, Human Research Ethics Committee. ResultsSix themes emerged from the extracted data; Journey to the MRI, Waiting, Anticipating the MRI procedure, Preparing for the MRI procedure, Negative interaction, and Fear of the results. ConclusionThe findings of this study provide novel self-reported and unsolicited insight into the diverse, multifactorial, and often concomitant nature of preprocedural MRI anxiety and distress. Implications for practiceThis study adds to a growing body of literature advocating for a compassionate, holistic, and person-centered approach when caring for patients in MRI that also considers their emotional and psychological wellbeing.

The use of novel 3D dark-blood late gadolinium enhancement MRI to determine the optimal threshold for atrial scar after pulmonary vein isolation ablation

Abstract Background Dark-blood late gadolinium enhancement (LGE) magnetic resonance imaging (MRI) is proved to be superior to bright-blood LGE MRI in localising subtle subendocardial scar in the ventricles, because of improved contrast between myocardial scar and blood. However, dark-blood LGE MRI has not yet been applied to identify atrial scar in the left atrium (LA) and therefore its threshold to determine scar is unknown. Purpose To determine the optimal intensity threshold for 3D dark-blood LGE MRI for atrial ablation scar after pulmonary vein isolation (PVI) Methods Twelve re-do PVI patients with symptomatic atrial fibrillation (AF) who underwent pre-procedural 3D dark-blood LGE MRI were included. The image intensity ratio (IIR = myocardial intensity normalized to the blood pool) from the LGE MRI were calculated using ADAS-AF. High-density bipolar voltages (BiV) maps were recorded during sinus rhythm prior to ablation. All BiV locations ≤5 mm from the ADAS LA anatomy were compared with the corresponding IIR, using custom-made software in MATLAB. To achieve an equal ratio between scar (BiV ≤0.15 mV) and non-scar (BiV >0.15 mV) for each patient, non-scar pairs were randomly resampled to the same number as scar pairs. This was repeated 10 times and for every random selection, receiver operating characteristics (ROC) analysis was performed to determine the optimal IIR threshold (provided by the Youden's index) for scar defined as BiV <0.15 mV (Figure 1). All IIR thresholds and areas under the curve were averaged to determine the overall performance and optimal IIR threshold. Results Of the 12 included patients, 8 had prior cryo PVI, 2 radiofrequency PVI, and 2 surgical/hybrid AF ablation. ROC curve analysis estimated the average optimal threshold for predicting BiV <0.15 mV to be an IIR of 1.106, with a mean area under the curve (AUC) of 0.73 (Figure 1). Figure 2 shows two examples of the IIR map (A), BiV map (B), and the correspondence map (C) providing information on spatial agreement between IIR and BiV. This individual qualitative assessment provides insight into the spatial variation between techniques and may facilitate future studies on the pathophysiological understanding of atrial ablation scarring. Conclusion This is the first study to use the novel 3D dark-blood whole heart LGE MRI to evaluate LA ablation scar after PVI. Based on the ROC analyses, an IIR of 1.106 is the optimal threshold for atrial ablation scar, defined as high density bipolar voltage <0.15 mV. Funding Acknowledgement Type of funding sources: None.

Preoperative MRI Classification May Not Predict Symptom Relief after Uterine Artery Embolization in Patients with Adenomyosis.

To investigate the association between magnetic resonance imaging (MRI) classification and symptom relief after uterine artery embolization (UAE) in patients with adenomyosis. Totally, 73 patients with symptomatic adenomyosis who underwent UAE were retrospectively analyzed. Preoperative MRI classification was defined as: type I, high signal on both T2-weighted images (T2WI) and T1-weighted images (T1WI); type III, high signal only on T2WI, and type II, high signal on neither T1WI nor T2WI. Dysmenorrhea was measured with the visual-analog scales and the degree of menorrhagia was measured according to the number of sanitary pads used in one menstrual cycle. Dysmenorrhea and menorrhagia were measured before UAE and 12 months after UAE. The number of the type I, II, III cases was 23, 37, and 13, respectively. The baseline characteristics of the three groups exhibited no significant difference. The alleviation rates of dysmenorrhea among type I, II, III cases were 73.9%, 89.2%, and 84.6%, respectively (P=0.455). The alleviation rates of menorrhagia for type I, II, III were 69.6%, 78.4%, and 92.3%, respectively (P=0.714). Pre-procedure MRI classification and symptom relief after UAE exhibited no significant association. UAE has a favorable mid-term control on dysmenorrhea and menorrhagia among patients with adenomyosis. Preoperative MRI classification might not indicate symptom relief. More research is needed before changing clinical practice.

Percutaneous transluminal angioplasty and stenting of post-irradiated stenosis of subclavian artery

The therapeutic efficacy of percutaneous transluminal angioplasty and stenting (PTAS) of post-irradiated stenosis of subclavian artery (PISSA) was not well clarified. This retrospective study was designed to evaluate the technical safety and outcome of the patients of severe symptomatic PISSA accepted PTAS. Between 2000 and 2019, 16 cases with 17 lesions of symptomatic and medically refractory PISSA accepted PTAS were included. We evaluated their technical success, peri-procedural complications and diffusion-weight imaging (DWI) of brain magnetic resonance imaging (MRI), results of symptom relief, and long-term stent patency. The stenosis of the 17 stenotic lesions were 81.2±11.1%. The most common symptom of the 16 patients was dizziness (14/16, 87.5%). All successfully accepted PTAS without neurological complication and had symptom relief after PTAS (17/17, 100%). Of the 12 patients accepted pre-procedural and early post-procedural MRI follow-up, 2 patients had an asymptomatic tiny acute embolic infarct in the territory of vertebrobasilar system. In a 51.9±54.9 months follow-up, all patients had no severe restenosis and no recurrent vertebrobasilar ischemic symptoms. For patients with PISSA and medically refractory ischemic symptoms, PTAS can be an effective alternative management.

Spinal nerve signal intensity on Dixon T2-weighted water-only sequence: an important outcome predictor after lumbar transforaminal epidural injection.

To evaluate the role of Dixon T2-weighted water-fat separation technique in predicting the outcome of lumbartransforaminal epidural injections (TFESIs). Patients who underwent TFESI of a single spinal nerve within 3 months after magnetic resonance imaging (MRI) exam between August 2018 and April 2020 were identified. The patients were classified into positive or negative outcome groups based on the response to the TFESI procedure. Two musculoskeletal radiologists measured the signal intensity of the injected side spinal nerves, contralateral side spinal nerves, and subcutaneous fat on axial Dixon T2-weighted water-only images, and the diameter of spinal nerve on axial Dixon T2-weighted in-phase images of the pre-procedural MRI. The measured values of the injected side spinal nerves were compared between the two groups and with the contralateral side spinal nerve. A total of 94 patients were included, 76 in the positive outcome group and 18 in the negative outcome group. The mean signal intensity and the nerve-to-fat signal ratio of the injected side spinal nerve were significantly higher in the positive outcome group than in the negative outcome group (793.78 vs. 679.19, p = 0.016; 4.21 vs. 3.28, p = 0.003). In the positive outcome group, the diameter of the spinal nerve was significantly higher on the injected side than on the contralateral side (6.91 mm vs. 6.37 mm, p = 0.016). The mean signal intensity and the nerve-to-fat signal ratio of the spinal nerve on axial Dixon T2-weighted water-only images can help predict patient response to the TFESI. • Applying the Dixon technique to lumbar spine MRI can help predict patient response to the TFESI procedure. • An increased nerve-to-fat signal ratio and mean spinal nerve signal intensity on axial Dixon T2-weighted water-only images predicted favorable TFESI outcomes.

A novel non-invasive electrocardiographic imaging technique facilitates the preprocedural diagnostic workup of patients with infrequent ventricular arrhythmias

Abstract Funding Acknowledgements Type of funding sources: None. Background Catheter ablation (CA) fails in considerable numbers of patients with ventricular arrhythmias (VAs). Possible reasons include absence and non-inducibility, multifocal origin and anatomically difficult locations of premature ventricular complexes (PVCs) and ventricular tachycardias (VTs). A novel non-invasive electrocardiographic imaging (ECGI) diagnostic tool may help to determine the best treatment strategy of these patients. Purpose To evaluate outpatient ECGI (VIVO, View Into Ventricular Onset, Catheter Precision, NJ) to tailor treatment of patients with infrequent ventricular arrhythmias referred for CA. Methods Thirteen patients in an outpatient setting with VAs were included in this pilot-study. All patients underwent ECGI mapping using VIVO. It is a novel technique that localize the origin of VAs using a combination of 12-lead ECG and a patient specific 3D anatomical reconstruction of the heart and thorax using cardiac magnetic resonance imaging (MRI) or cardiac computed tomography imaging (CT). The technique is based on virtual simulation of pace-mapping and has a unique feature that the imaging can be performed independently from recording of the arrhythmias. Suitability for ablation was based on the VIVO mapping in this cohort. Results Among the 13 patients enrolled (10 female, 3 male, age 39 ±15 years), a total of 16 PVC/VT morphologies were analyzed using VIVO. Ten of them had a low PVC burden (<8%). Ten patients underwent pre-procedural cardiac MRI and 4 had CT imaging. Seven of the patients had structurally normal hearts, while the remaining 6 had non-ischemic cardiomyopathy. Based on the VIVO mapping findings the patients were divided in two groups. Group A: 7 patients in whom ablation was considered suitable. In this group a VIVO based anatomy CA was attempted in 3 patients for PVCs. Two out of these were successful. Three patients were offered CA but was declined by patient decision (suboptimal balance between burden, complaints and the offered success rates without procedural hard endpoint). Another patient is offered and is waiting for CA. The other group B: 6 patients in whom VIVO mapping was consistent with an unacceptable chance for treatment success were not offered CA. This included: 4 patients with a multifocal origin and a low burden of PVCs. One patient had different diagnosis (atrial fibrillation) and another had no PVC’s during 12-lead ECG monitoring. Conclusions Non-invasive ECGI pace-map is a unique tool that can identify the origin of infrequent VAs in an outpatient clinical setting in order to screen out patients not feasible for CA. Low burden PVCs maybe attempted to be ablated when the source is clearly associated of certain anatomical structures.

Percutaneous spine biopsy under cone beam computed tomography guidance for spondylodiscitis: Time is diagnosis.

Percutaneous spine biopsies for spondylodiscitis have been long discussed due to the low microbiologic yield. This retrospective study evaluated factors of cone beam computed tomography-guided spine biopsies that may affect microbiologic yield. We retrospectively reviewed percutaneous spine biopsies under cone beam computed tomography for spondylodiscitis performed from January 2015-December 2020. Clinical and technical features such as the time from initial symptoms to biopsy, level biopsied, biopsy needle type/gauge, technical approach, radiation dose, technical success and microbiologic yield were recorded. Pre-procedure magnetic resonance imaging findings were also recorded such as the number of vertebral bodies involved, and disc morphology. Univariate logistic regression analysis and Receiver operating characteristic analysis were performed to assess any relationship between relevant factors and positive cultures. A total of 50 patients underwent cone beam computed tomography-guided biopsies for spondylodiscitis, with resulted positive cultures in 18 patients (36%). The mean time from the initial referral of spinal symptoms to procedure in the positive culture group was the most influential finding for positive cultures (odds ratio 56.3, p < 0.001). Among magnetic resonance imaging findings, thin or degenerated intervertebral disc was a negative factor for positive cultures (odds ratio 0.09, p = 0.006). Univariate analysis showed that percutaneous approach (transpedicular vs posterolateral/interlaminar) needle size (11-13 g vs 16-18G, odds ratio 1.2, p = 0.7) and site of biopsy (disc vs bone vs disc plus endplate) did not significantly affect the microbiologic yield of spine biopsy. Percutaneous cone beam computed tomography-guided biopsy for spondylodiscitis is a reliable and safe technique and its microbiologic yield may increase if biopsy is performed within the acute phase of infection.

Improving Ablation Safety for Hepatocellular Carcinoma Proximal to the Hilar Bile Ducts by Ultrasound-MR Fusion Imaging: A Preliminary Comparative Study.

AimTo explore whether ablation safety could be improved by ultrasound (US)-magnetic resonance (MR) fusion imaging for hepatocellular carcinoma (HCC) proximal to the hilar bile ducts (HBDs) through a preliminary comparative study.MethodsBetween January 2014 and June 2019, 18 HCC nodules proximal to the HBDs were included in a US-MR fusion imaging-assisted radiofrequency ablation (RFA) group (study group), while 13 HCC nodules in a similar location were included as a control group. For the study group, the tumor and adjacent bile ducts were outlined on preprocedural MR images. Procedural ablation planning was conducted to assess the feasibility of ablating the tumors while avoiding biliary injury. Such tumors were then ablated under US-MR fusion imaging guidance. The control group nodules were ablated under conventional ultrasound guidance. Baseline characteristics and outcomes were compared between the groups.ResultsAfter preprocedural assessment, 14 of 18 patients with tumors that were feasible to ablate underwent US-MR fusion imaging-assisted RFA. No biliary complications were observed in these 14 patients; the complication rate was significantly lower in the study group than in the control group (30.8%, 4/13) (P = 0.041). There was no significant difference in the technique efficacy rates [92.9% (13/14) versus 100% (13/13), P = 1] or local progression rates [7.1% (1/14) versus 7.7% (1/13), P = 1] between the study and control groups.ConclusionsUS-MR fusion imaging may be a non-invasive means for assisting RFA of HCC nodules proximal to the HBDs and ensuring ablation safety.

Abstract 16829: Isolated Left Atrial, Biatrial or Right Atrial Dilatation - Association With Low Voltage Areas in Patients With Atrial Fibrillation

Background: Left atrial volume (LAV) and low voltage areas (LVA) are markers for impaired outcome after ablation of atrial fibrillation (AF). Some studies reported the importance of increased right atrial volume (RAV) as a predictor for arrhythmia recurrences in AF patients. Hypothesis: to investigate association between the LAV/RAV ratio and LVA presence. Methods: Patients undergoing first AF ablation with pre-procedural cardiovascular magnetic resonance (CMR) imaging were included. LVA were assessed peri-procedurally using high-density 3D maps and defined as &lt;0.5 mV. LAV was determined using a biplane model based on cine 4- and 2-chamber views, RAV using a monoplane model based on the cine 4-chamber view. Both volumes were indexed to body surface areas, and the LAV/RAV ratio was calculated. LAV/RAV ratio &gt;1 indicated isolated LA dilatation, ratio ≤1 was defined as biatrial/isolated RA dilatation. Results: The study population included 184 patients (Age 63±10 years, 34% women, 58% persistent AF, 22% LVA). There were 148 (80%) patients with isolated LA dilatation. In univariable analysis, isolated LA dilatation was associated with LVAs (OR 6.803, 95% CI 1.395-26.514, p=0.016). This association remained robust in multivariable model after adjustment for persistent AF, CHA 2 DS 2 -VASc score, renal function, and heart rate (OR 5.981, 95%CI 1.256-28.484, p=0.025). Using ROC analysis, LAV/RAV ratio (AUC 0.668, 95% CI 0.585-0.751, p&lt;0.001, Figure) was significant predictor for LVA. Biatrial/isolated RA dilatation occurred in 36 (20%) patients. On multivariable analysis, after adjustment for age, persistent AF, and renal function, male sex remained significantly associated with biatrial/isolated RA dilatation (OR 3.040, 95% CI 1.050-8.802, p=0.040). Conclusions: LAV/RAV ratio is useful for the prediction of LVA in AF. Isolated LA dilatation was associated with LVA presence, while male sex remained associated with biatrial/isolated RA dilatation and less LVA.

Right ventricular rather than left ventricular systolic dysfunction predicts outcome in patients undergoing transcatheter aortic valve implantation: insights from cardiac magnetic resonance imaging

Abstract Background Right ventricular (RV) function is strongly associated with outcome in heart failure. Whether it also adds important prognostic information in patients undergoing transcatheter aortic valve implantation (TAVI) is unknown. Methods We consecutively enrolled patients with severe aortic stenosis (AS) scheduled for TAVI and preprocedural cardiac magnetic resonance (CMR) imaging. Kaplan-Meier estimates and multivariate Cox regression analyses were used to identify factors associated with outcome. A composite of heart failure hospitalization and/or cardiovascular death was selected as primary study endpoint. Results 423 consecutive patients (80.7±7.3 years; 48% female) were prospectively included, 201 (48%) underwent CMR imaging. 55 (27%) patients presented with RV systolic dysfunction (RVSD) defined by RV ejection fraction (RVEF) &amp;lt;45%. RVSD was associated with male sex (69 vs. 40%; p&amp;lt;0.001), New York Heart Association (NYHA) functional status (NYHA ≥ III: 89 vs. 57%; p&amp;lt;0.001), NT-proBNP serum levels (9365 vs. 2715 pg/mL; p&amp;lt;0.001), and history of atrial fibrillation (AF: 51 vs. 30%; p=0.005). On CMR, RVSD was associated with left ventricular (LV) volumes (end-diastolic: 187 vs. 137 mL, end-systolic: 119 vs. 53 mL; p&amp;lt;0.001) and EF (39 vs. 64%; p&amp;lt;0.001). A total of 51 events (37 deaths, 14 hospitalizations for heart failure) occurred during follow-up (9.8±9 months). While LVSD (LVEF &amp;lt;50%) was not significantly associated with outcome (HR 0.83, 95% CI: 0.33 – 2.11; p=0.694), RVSD showed a strong and independent association with event-free survival by multivariate Cox regression analysis (HR 2.47, 95% CI: 1.07–5.73; p=0.035), which was adjusted for all relevant CMR parameters (LV volumes and EF), cardiovascular risk factors (sex, NYHA, AF, diabetes mellitus type II, use of diuretics), and routine biomarkers (NT-proBNP, creatinine). Conclusions RVSD rather than LVSD, as determined on CMR, is an important predictor of outcome in patients undergoing TAVI. RV function might thus add useful prognostic information on top of established risk factors. Figure 1. Kaplan-Meier survival curves Funding Acknowledgement Type of funding source: None

Design, Development, and Multi-Characterization of an Integrated Clinical Transrectal Ultrasound and Photoacoustic Device for Human Prostate Imaging.

The standard diagnostic procedure for prostate cancer (PCa) is transrectal ultrasound (TRUS)-guided needle biopsy. However, due to the low sensitivity of TRUS to cancerous tissue in the prostate, small yet clinically significant tumors can be missed. Magnetic resonance imaging (MRI) with TRUS fusion biopsy has recently been introduced as a way to improve the identification of clinically significant PCa in men. However, the spatial errors in coregistering the preprocedural MRI with the real-time TRUS causes false negatives. A real-time and intraprocedural imaging modality that can sensitively detect PCa tumors and, more importantly, differentiate aggressive from nonaggressive tumors could largely improve the guidance of biopsy sampling to improve diagnostic accuracy and patient risk stratification. In this work, we seek to fill this long-standing gap in clinical diagnosis of PCa via the development of a dual-modality imaging device that integrates the emerging photoacoustic imaging (PAI) technique with the established TRUS for improved guidance of PCa needle biopsy. Unlike previously published studies on the integration of TRUS with PAI capabilities, this work introduces a novel approach for integrating a focused light delivery mechanism with a clinical-grade commercial TRUS probe, while assuring much-needed ease of operation in the transrectal space. We further present the clinical potential of our device by (i) performing rigorous characterization studies, (ii) examining the acoustic and optical safety parameters for human prostate imaging, and (iii) demonstrating the structural and functional imaging capabilities using deep-tissue-mimicking phantoms. Our TRUSPA experimental studies demonstrated a field-of-view in the range of 130 to 150 degrees and spatial resolutions in the range of 300 μm to 400 μm at a soft tissue imaging depth of 5 cm.

Automatic Detection of Slow Conducting Channels during Substrate Ablation of Scar-Related Ventricular Arrhythmias

Background Voltage mapping allows identifying the arrhythmogenic substrate during scar-related ventricular arrhythmia (VA) ablation procedures. Slow conducting channels (SCCs), defined by the presence of electrogram (EGM) signals with delayed components (EGM-DC), are responsible for sustaining VAs and constitute potential ablation targets. However, voltage mapping, as it is currently performed, is time-consuming, requiring a manual analysis of all EGMs to detect SCCs, and its accuracy is limited by electric far-field. We sought to evaluate an algorithm that automatically identifies EGM-DC, classifies mapping points, and creates new voltage maps, named “Slow Conducting Channel Maps” (SCC-Maps). Methods Retrospective analysis of electroanatomic maps (EAM) from 20 patients (10 ischemic, 10 with arrhythmogenic right ventricular dysplasia/cardiomyopathy) was performed. EAM voltage maps were acquired during sinus rhythm and used for ablation. Preprocedural contrast-enhanced cardiac magnetic resonance (Ce-CMR) imaging was available for the ischemic population. Three mapping modalities were analysed: (i) EAM voltage maps using standard (EAM standard) or manual (EAM screening) thresholds for defining core and border zones; (ii) SCC-Maps derived from the use of the novel SCC-Mapping algorithm that automatically identify EGM-DCs measuring the voltage of the local component; and (iii) Ce-CMR maps (when available). The ability of each mapping modality in identifying SCCs and their agreement was evaluated. Results SCC-Maps and EAM screening identified a greater number of SCC entrances than EAM standard (3.45 ± 1.61 and 2.95 ± 2.31, resp., vs. 1.05 ± 1.10; p < 0.01). SCC-Maps and EAM screening highly correlate with Ce-CMR maps in the ischemic population when compared to EAM standard (Lin's correlation = 0.628 and 0.679, resp., vs. 0.212, p < 0.01). Conclusion The SCC-Mapping algorithm allows an operator-independent analysis of EGM signals showing better identification of the arrhythmogenic substrate characteristics when compared to standard voltage EAM.

3:09 PM Abstract No. 299 Automatic machine learning based on routine pre procedure magnetic resonance imaging to predict response of hepatocellular carcinoma following transcatheter arterial chemoembolization

The purpose of this study was to apply automatic machine learning on routine pre procedure MR to predict treatment response of patients with hepatocellular carcinoma (HCC) following transcatheter arterial chemoembolization (TACE). 212 patients with histologically confirmed singe-lesion HCC who only underwent one TACE procedure with available pre and post procedure MR scans were identified from one large academic institution from 2008 to 2018. The preoperative MR examination including T1-contrast-enhanced sequences (T1C) and T2-weighted sequence (T2WI) were manually segmented using 3D Slicer software. For each image space, 56 non-texture (morphology and intensity-based) and 94 texture features were extracted according to the guidelines defined by the Image Biomarker Standardization Initiative. Each of the 94 texture features were computed 32 times using all possible combinations of the following extraction parameters, a process known as “texture optimization”: (i) isotropic voxels of size 1 mm, 2 mm, 3 mm, and 4 mm, (ii) fixed bin number (FBN) discretization algorithm, with and without equalization, (iii) the number of gray levels of 8, 16, 32, and 64 for FBN for a total of (56 + 32*94), or 3064 radiomics features. All the features were normalized and features from T1C and T2WI were combined with 41 clinical variables to be inputted into TPOT, a Tree-Based Pipeline Optimization Tool that chooses the most optimal machine learning pipeline for an inputted dataset through genetic programming, to predict complete response (CR) vs. partial, stable or progressive disease (Non-CR) according to modified RECIST criteria. Among the 212 patients, 126 patients achieved CR and 86 non-CR. The dataset was randomly divided into 70% training and 30% testing set. After running TPOT (generation=50, population_size=100, cv=5, scoring=“balanced_accuracy”), the final cross-validation score was 0.68. The best model achieved validation accuracy of 75.0% (AUC=0.72) with 87.2% sensitivity and 0.56 specificity. Our preliminary results demonstrate automatic machine learning based on routine pre procedure MR can predict response after TACE with good accuracy. Further validation is needed in a larger multi-institutional cohort.

Additional Magnetic Resonance or Nuclear Scintigraphy Imaging Influences Approach to Vertebral Augmentation: A Single Institution Experience.

Retrospective review. To ascertain impact of preprocedural magnetic resonance imaging (MRI) or nuclear medicine Tc99m-DMP scintigraphy on the treatment plan when compared with plain films and/or computed tomography prior to vertebral augmentation procedures. Over 1 million vertebral compression fractures (VCFs) occur in the United States annually with over 150,000 individuals hospitalized each year. Physical examination and history are essential to the workup of VCFs, but imaging remains necessary for confirming the diagnosis. VCFs can be imaged with various modalities and there is limited data on the comparative effectiveness of different imaging modalities. Six hundred fifty consecutive patients treated with vertebral augmentation at a single institution between May of 2013 and April of 2018 were reviewed. Preprocedure imaging of the spine obtained within 30 days prior to the procedure were reviewed. Preprocedure imaging results were cross-referenced against the levels treated by vertebral augmentation to determine whether there was a change in the levels treated after receiving an MRI or NM imaging study. Three hundred sixty-three patients had adequate imaging for inclusion. One hundred fifty-four of these 363 patients (42.4%) had an alteration of their treatment plan based upon the MR or NM imaging. Fewer vertebral levels were treated in 33, different levels were treated in 41, and more levels were treated in 80 patients. MRI or nuclear medicine bone scan imaging prior to vertebral augmentation altered the location and number of levels treated in a large percentage of patients, adding specificity to treatment over findings on radiographs or computed tomography alone. 3.

Von Willebrand factor (VWF) as a determinant of silent cerebral microbleeds during TAVR in a prospective MRI cohort

Cerebral microbleeds have been observed in “asymptomatic” elderly patients undergoing systematic MRIs and might be related with cognitive decline. A defect in Von Willebrand factor (VWF) after Trans Aortic-valve Replacement (TAVR) enhanced bleeding risk and possibly contributes to vascular malformations. To define the occurrence of “acute” microbleeds during TAVR and the clinical and procedural factors associated with this occurrence including a post-procedural defect in VWF. A prospective cohort of patients with aortic stenosis referred for TAVR was included. A standardized neurological assessment, a cerebral magnetic resonance imaging (MRI) and a biological analysis including quantification of VWF multimers and PFA-CADP were performed before and after TAVR. Eighty-four patients completed the imaging protocol. On pre-procedural MRI, 22 patients (26%, 95%CI = 17–37%) had at least one microbleeds. After TAVR, new microbleeds were observed in 19 (23%, 95%CI = 14–33%) patients. The occurrence of new microbleeds was independent of the presence microbleeds at baseline. A lower HMW-multimer-ratio as measured immediately at the end of the procedure was associated with the occurrence of new microbleed detected on the MRI performed 3 days after the procedure (0.90 ± 0.14 vs. 1.06 ± 0.27, P = 0.009). The same observation was made with a higher CT-ADP (165 ± 72 vs. 127 ± 57, P = 0.02). A prolonged procedure (RR = 1.21 [1.01–1.170] for every 5 min of fluoroscopy time, P = 0.04) and post-procedural acquired-VWF-defect (RR = 1.42 [1.08–1.89] for every lower “0.1 unit” of HMW-multimer-ratio, P = 0.004) were the only factors associated with the occurrence of new post-procedural microbleed(s). We report for the first time a high incidence (23%, 95%CI = 14–33%) of new post-procedural cerebral microbleeds occurring during TAVR. Procedural management and persistence of acquired-VWF defect could play a major role in the occurrence of those new microbleeds.

Esophageal Thermal Injury FollowingCryoballoon Ablation forAtrialFibrillation.

This study evaluated the rate and predictors of endoscopically detected esophageal thermal lesions (EDEL) in patients who underwent cryoballoon atrial fibrillation (AF) ablation (CBA). EDEL is a known complication of catheter ablation for AF and is the inciting factor for atrial esophageal fistula formation. An observational study was conducted of patients with AF presenting for CBA. Pre-procedural magnetic resonance imaging was used to retrospectively evaluate the distance between the atrial endocardium and the esophageal lumen (AED). Intraprocedural esophageal luminal temperature and balloon temperatures were recorded. All patients underwent upper endoscopy (EGD) 24h post-ablation. Clinical, anatomical, and ablation parameters were analyzed using logistic regression for association with thermal injury. A total of 95 patients (37% women; 71% paroxysmal AF) were included in the study. Esophageal thermal injury was detected on EGD in 21 patients (22%). EDEL was mostly mild (20 of 21 patients) and severe in only 1 of 21 patients. Univariate logistic regression identified gastroesophageal reflux disease to be associated with increased risk of thermal injury (odds ratio [OR]: 3.2; 95% confidence interval [CI]: 1.00 to 10.46; p=0.04), whereas a wider AED was protective (OR: 0.16; 95%CI: 0.05 to 0.515; p=0.002). Esophageal wall thickness was also protective (OR: 0.04; 95%CI: 0.002 to 0.864; p=0.04). In multivariate analysis, only AED (OR: 0.22; 95%CI: 0.06 to 0.77; p=0.018) and obesity (OR: 4.63; 95%CI: 1.13 to 18.97; p=0.033) were associated with EDEL. Esophageal luminal temperature, number, and duration of cryoballoon applications and balloon temperature were not predictors of EDEL. EDEL following CBA occurred in 22% of patients and was mostly mild. Obesity and atrioesophageal distance were independently associated with increased risk.