Pre-procedural CT Research Articles

A validated computational framework to predict outcomes in TAVI

Transcatheter aortic valve implantation (TAVI) still presents complications: paravalvular leakage (PVL) and onset of conduction abnormalities leading to permanent pacemaker implantation. Our aim was testing a validated patient-specific computational framework for prediction of TAVI outcomes and possible complications. Twenty-eight TAVI patients (14 SapienXT and 14 CoreValve) were retrospectively selected. Pre-procedural CT images were post-processed to create 3D patient-specific implantation sites. The procedures were simulated with finite element analysis. Simulations’ results were compared against post-procedural clinical fluoroscopy and echocardiography images. The computational model was in good agreement with clinical findings: the overall stent diameter difference was 2.6% and PVL was correctly identified with a post-processing algorithm in 83% of cases. Strains in the implantation site were studied to assess the risk of conduction system disturbance and were found highest in the patient who required pacemaker implantation. This study suggests that computational tool could support safe planning and broadening of TAVI.

P1056Left atrial and left atrial appendage ejection fraction assessed by preprocedural cardiac CT are useful parameters for predicting the outcome of pulmonary vein isolation

Abstract Introduction Pulmonary vein isolation (PVI) is an effective but complex treatment option for atrial fibrillation (AF). Therefore preprocedural outcome prediction is of special interest. Left atrial volume (LAVmax) is a commonly used predictor for recurring arrhythmia. Several studies have investigated different parameters for the prediction of sustained rhythm control. We hypothesized that left atrial and left atrial appendage ejection fraction (LAEF & LAAEF) assessed by high-resolution CT-imaging are even more sensitive predictors of the outcome of PVI than LAVmax. Methods All patients who underwent PVI between 2015 and 2018 with available preinterventional cardiac CT were included in this retrospective study and separated into 2 groups: Group A comprises all patients with sinus rhythm (SR) at follow-up and group B all patients in whom recurrence of AF was observed. Volumetric analysis of the left atrium was performed in ventricular systole (30%-Phase of the cardiac cycle) and diastole (0%-Phase). Obtained data were used to calculate left atrial and left appendage ejection fractions (LAEF & LAAEF). Success of pulmonary vein isolation was defined as clinical freedom of symptomatic AF together with sinus rhythm on the available Holter-ECG recordings during follow-up examinations. Uni- and multivariate logistic regression models and NAMS RMLE tests were used to compare LAVmax to these functional parameters. Results In total 152 patients with symptomatic paroxsymal or persistent AF underwent PVI at our hospital from 2015 to 2018. Due to inconsistencies in archiving in our PACS-system, 98 patients had to be excluded from analysis. Four patients were excluded due to motion artifacts. 50 patients were included in the final study (41 patients without and 9 patients with recurring AF on average 254 days after ablation). Significant differences in means were found for all assessed parameters. LAEF (accuracy 94%, sensitivity 67%) and LAAEF (accuracy 90%, sensitivity 67%) had a higher sensitivity than LAVmax (accuracy 86%, sensitivity 33%), though not significant in this study population (p = 0.18). LAVmax and LAEF in combination improved sensitivity significantly from 33% to 78% (p = 0.046). Measurements on cardiac-CT showed an excellent interobserver-reliability. Conclusion Reduced LAEF and LAAEF were found to be significant predictors of the outcome of PVI. Furthermore we found a trend that these functional parameters might be more sensitive than LAVmax. Thus we propose that left atrial function, assessed with preprocedural cardiac CT, offers important prognostic information for successful PVI. Abstract Figure. Surface rendering of LA and LAA

Supra-annular sizing of transcatheter aortic valve prostheses in raphe-type bicuspid aortic valve disease: the LIRA method

BackgroundRecent evidence shows that THV prostheses anchoring occurs at the raphe-level, known as LIRA plane, in raphe-type bicuspid aortic valve (BAV) disease. The purpose of this study was to evaluate the application of a novel supra-annular sizing method, known as Level of Implantation at the RAphe (LIRA) method, to optimize transcatheter heart valve (THV) prosthesis sizing in raphe-type BAV disease. Methods and resultsThe LIRA method was applied to all consecutive patients with raphe-type BAV disease between November 2018 to January 2020 in our centre. THV prostheses were sized on the basis of baseline CT scan perimeters at the LIRA plane and at the virtual basal ring. In case of discrepancy between the two plane measurements, the plane with the smallest perimeter was considered the reference for prosthesis sizing. Post-procedural device success, defined according to Valve Academic Research Consortium–2 (VARC-2) criteria, was evaluated in the overall cohort. 20 patients (mean patient age 81 ± 5.4 years, 70% males) were identified as having a raphe-type BAV disease at pre-procedural CT scans and were implanted with different types of THV prostheses. The LIRA plane method appeared to be highly successful (100% VARC-2 device success) with no procedural mortality, no valve migration, no moderate-severe paravalvular leak and low transprosthetic gradient (residual mean gradient of 8.2 ± 2.9 mm Hg). ConclusionsSupra-annular sizing according to the LIRA method appeared to be safe with a high device success. The application of the LIRA method might optimize THV prosthesis sizing in patients with raphe-type BAV disease.

Exophthalmos following mechanical thrombectomy for anterior circulation stroke: A retrospective study and review of literature.

Anecdotal cases of exophthalmos after acute mechanical thrombectomy have been described. We sought to estimate the incidence in a large cohort of patients with acute anterior circulation stroke treated with mechanical thrombectomy. Secondarily, we aimed to evaluate the underlying mechanism and to differentiate it on imaging from other pathology with similar clinical orbital features. Between November 2016 and November 2018, we performed a retrospective single-center study of 250 patients who underwent anterior circulation mechanical thrombectomy. Development of exophthalmos was independently evaluated by two readers on preprocedure and 24-h postprocedure non-contrast cerebral CT. In the mechanical thrombectomy cohort, six individuals (2.4%) developed interval ipsilateral exophthalmos at 24 h. Of these, at least two patients developed clinical symptoms. There was almost perfect agreement between assessments of the two readers (Cohen's kappa = 0.907 (95% confidence interval: 0.726, 1.000)). In two patients, there was delayed ophthalmic artery filling on digital subtraction angiography. None of the patients had features of a direct carotid-cavernous fistula. Exophthalmos is not uncommon after mechanical thrombectomy (2.4%). The underlying mechanism is difficult to confirm, but it is most likely due to orbital ischemia from hypoperfusion or distal emboli.

Pneumothorax and pulmonary hemorrhage after CT-guided lung biopsy: incidence, clinical significance and correlation.

To evaluate the incidence and clinical significance of pneumothorax (PTX) and pulmonary hemorrhage (PH) after CT-guided lung biopsy (CT-LB). To test correlations of PTX and chest tube insertion (CTI) with PH and other imaging and procedural parameters. Pre-procedural CT and CT-LB scans of 904 patients were examined. Incidence of PTX and PH and PH location (type-1 along needle track; type-2 perilesional) and severity according to its thickness (low grade < 6mm; high grade > 6mm) were recorded. PTX was considered clinically significant if treated with CTI, PH if treated with endoscopic/endovascular procedure. Binary logistic regression analyses were used to determine the effects of different imaging and procedural parameters on the likelihood to develop PTX, CTI and PH and to define their correlation. PTX occurred in 306/904 cases (33.8%); CTI was required in 18/306 (5.9%). PH occurred in 296/904 cases (32.7%), and no case required treatment. Nodule-to-pleura distance (ORPTX = 1.052; ORCTI = 1.046; ORPH 1.077), emphysema (ORPTX = 1.287; ORPH = 0.573), procedure time (ORPTX = 1.019; ORCTI = 1.039; ORPH = 1.019), target size (ORPTX = 0.982; ORPH = 0.968) and needle gauge (ORPTX = 0.487; ORCTI = 4.311; ORPH = 2.070) showed statistically significant correlation to PTX, CTI and PH. Type-1 PH showed a protective effect against PTX and CTI (ORPTX = 0.503; ORCTI = 0.416). PTX and PH have similar incidence after CT-guided lung biopsy. PH along needle track may represent a protective factor against development of PTX and against PTX requiring CTI.

Spontaneously occluded left atrial appendage in a patient with atrial fibrillation and stroke: a case report.

Background The left atrial appendage (LAA) is the main source of thromboembolism in atrial fibrillation (AF). Transcatheter closure is non-inferior to warfarin therapy in preventing stroke.Case summary A patient with two consecutive strokes associated with AF was referred for transcatheter LAA occlusion (LAAO). Preprocedural cardiac CT and transoesophageal echocardiography demonstrated a spontaneously occluded LAA with a smooth left atrial surface, with stationary results at 6- and 12-month imaging follow-up. Warfarin was discontinued, and life-long aspirin instigated.Discussion Left atrial appendage occlusion has shown non-inferiority to warfarin for prevention of stroke, cardiovascular death, and all-cause mortality. No benefits from anticoagulation have been demonstrated in patients with embolic stroke of undetermined source. In the present case, we observed that the LAA was occluded and, therefore, treated with aspirin monotherapy assuming similar efficacy as transcatheter LAAO.

Endovascular Treatment Outcome and CT Angiography Findings in Acute Basilar Artery Occlusion with and without Underlying Intracranial Atherosclerotic Stenosis

PurposeTo compare clinical characteristics and treatment outcomes of intra-arterial thrombectomy (IAT) in acute basilar artery occlusion (BAO) with and without underlying intracranial atherosclerotic stenosis (ICAS) and to investigate the usefulness of preprocedural CT angiography findings in the diagnosis of ICAS. Materials and MethodsTwenty patients who received IAT for acute BAO between September 2014 and March 2019 were included. Additional therapies such as angioplasty, stent placement, and tirofiban infusion were provided while treating ICAS. Clinical and angiographic results of treatment were recorded. Preprocedural CT angiography findings in ICAS and non-ICAS groups were compared to assess (i) basilar tip opacification, (ii) partial occlusion, (iii) presence of convex border, (iv) occlusion segment longer than two thirds of the basilar artery or 20 mm, (v) dense basilar artery, and (vi) wall calcification in the occluded segment. ResultsAmong the 20 patients (mean age, 71.3 y; mean stroke score, 24.8), optimal recanalization was achieved in 19 (95%). Three patients had good clinical outcomes. There were 6 patients with underlying ICAS. No difference was observed between ICAS and non-ICAS groups in terms of optimal angiographic recanalization and good outcome. On CT angiography, basilar tip occlusion (100% vs 29%), partial occlusion (100% vs 83%), and long occlusion length (100% vs 14%) significantly differed between the groups (P ≤ .01). ConclusionsIn acute BAO, underlying ICAS does not affect optimal recanalization rate or clinical outcome. Preprocedural CT angiography is a potentially useful tool to detect it.

4:03 PM Abstract No. 297 True three-dimensional holographic visualization for performance of percutaneous thermal ablation of solid liver tumors: an update on in-human evaluation

Earlier work has demonstrated bench targeting accuracy, usability, and first-in-human feasibility of an augmented-reality platform developed for 3D-HPA. The purpose of this study is to further evaluate the clinical feasibility of this novel technology. Five patients clinically indicated for microwave liver tumor ablation were enrolled in an IRB-approved protocol. Preprocedural multiphasic CT angiography (CTA) was acquired in all patients with the addition of fiducial skin markers for intraprocedural registration. 3D HPA integrates HoloLens (Microsoft, WA, USA) guidance with electromagnetic tracking of instruments to generate, register, and project holograms directly to the operative site as the instrument is navigated. Holograms are based on structures segmented from CTA (e.g., liver, vessels, tumor, bone) and a holographic light ray (HLR) co-axially extending from the tracked instrument. As standard of care, ultrasound was used for percutaneous placement of the trocar and all surgical decisions; for minimal risk to the patient at this early stage of development, holograms were only visible prior to percutaneous access and after the trocar was placed. Following ablation, images and video from postprocedural sonography, cone-beam and multidetector row CT, and HoloLens recordings were evaluated. Five patients were treated during this evaluation of 3D-HPA. In all five cases, intraprocedural holographic guidance, including HLR navigation, was in agreement with ultrasound-based guidance, as defined by (1) visualization of the guidance track relative to critical structures and (2) placement of the ablation probe within the targeted tumor. Postprocedural imaging showed adequate tumor ablation coverage. There was no recurrence at 3-month follow-up in patients who had this imaging available for review. This first clinical series further demonstrated feasibility of 3D-HPA and its potential to improve the performance of PTA, which could lead to improved quality of patient care as well as benefits for the global health care system. Further development and evaluation for tumor ablation guidance, along with other IR applications, is ongoing.

4:12 PM Abstract No. 90 Transmediastinal dissection with radiofrequency wire reentry for bypass of long-segment thoracic central venous occlusions refractory to recanalization

In patients with severe chronic central venous occlusions that cannot be recanalized with routine methods, several tools and techniques for sharp recanalization have been reported as well as radiofrequency (RF) wire cautery. While effective, these devices can easily traverse adjacent ascending aorta and enter the pleural space and pericardium, all of which can have lethal consequences. The purpose of this study is to report outcomes of a novel technique to intentionally perforate out of the venous system to allow blunt dissection with a soft-tip guidewire through the mediastinal fat alongside the occluded venous segment(s), then regain entry into the central venous system using the RF powerwire. Retrospective review of our procedural database over a 3-year period revealed 6 patients (3 females, mean age 56 years) with a long-segment central venous occlusion who failed attempted conventional blunt, sharp, or RF recanalization techniques and then underwent this bypass technique. A detailed review of preprocedural CT venogram was always first performed. After intentional perforation into the mediastinal fat, a soft-tipped guidewire and catheter were manipulated parallel to the occluded segment towards the patent target vein. Once adjacent to target vein wall, the RF power wire was then used solely to traverse vein wall into patent lumen, thus effectively bypassing the occlusion. Indications for this bypass technique included establishment of central venous access to allow HeRO insertion (n = 5) or port implantation for daily iron infusions (n = 1). The mean occlusion length was 5.3 cm (range, 4.0-8.4 cm). All 6 procedures were technically successful, allowing insertion of the desired catheter. No major complications were encountered within 30 days of the procedure. Transmediastinal dissection with RF wire reentry is a safe and effective technique to allow complete bypass of a long-segment venous occlusion to allow central venous access. The passage of a soft-tipped guidewire along fat planes may be less likely to enter pericardium, pleura, and arterial structures than needle and RF wire recanalization of long-segment occlusions.

Novel Anatomic Predictors of New Persistent Left Bundle Branch Block After Evolut Transcatheter Aortic Valve Implantation

New persistent left bundle branch block (NP-LBBB) has been associated with adverse outcomes after TAVI but few predictors thus far reported. We sought to identify predictors of NP-LBBB after TAVI with EvolutR/PRO (ER/EP). From 1/2016 to 4/2019, 544 patients from 2 centers underwent TAVI with Evolut (54% ER, 46% EP) for severe native aortic stenosis. Patients with previous LBBB and pacemaker were excluded. Aortic root analysis was performed using 3Mensio Valves Software and membranous septal length (MSL) was determined using the standard coronal view. Clinical, anatomic and procedural characteristics of 396 Evolut were analyzed and predictors of NP-LBBB were identified. Valve Academic Research Consortium-2 outcomes were reported. At discharge, NP-LBBB was seen in 76(19.2%) patients. NP-LBBB in Evolut was associated with implant depth at left coronary cusp (p = 0.004) and 34 mm ER (p = 0.026). Independent predictors of NP-LBBB in Evolut were shorter MSL (odds ratio [OR] = 0.82 per mm septum, 95% confidence interval [CI] = 0.68 to 0.98,p = 0.030), left ventricular outflow tract (LVOT) eccentricity (OR = 1.04 per %, 95% CI = 1.01 to 1.06,p = 0.002), implant depth at noncoronary cusp (NCC) (OR = 1.28 per mm ventricular, 95% CI = 1.11 to 1.48,p = 0.001) and annular perimeter oversizing ≥20% (OR = 2.38, 95% CI = 1.20 to 4.72, p = 0.013). On ROC curve analysis, MSL ≤6.5 mm, NCC depth ≥3 mm and LVOT eccentricity ≥35% were optimal threshold values to predict NP-LBBB. In Conclusion, shorter MSL, LVOT eccentricity, annular oversizing and deeper implant depth are novel predictors of NP-LBBB in Evolut TAVI. Preprocedural CT assessment of aortic root anatomy may help identify patients at risk for NP-LBBB. In such patients, modifying procedural factors such as higher implant and less annular oversizing may reduce the risk of NP-LBBB. Further evaluation of our hypothesis is warranted.

P1423 Significantly higher 1-year mortality rate in patients undergoing TAVR with higher right ventricular volumes, as calculated by pre-procedural CT angiography

Abstract Background Cardiac gated computed tomography angiography (CCTA) is the mandatory pre-interventional imaging planning procedure in patients eligible for trans-catheter valve implantation (TAVR). Automated analysis of the cardiac chambers" volumes including the right ventricle (RV), can be obtained from the CCTA and thus contribute to patient selection. Objectives To assess the prognostic implications of increased RV volume using a fast automated volumetric analysis software on preprocedural CCTA data among patients undergoing TAVR. Methods CCTA of patients who underwent TAVR at two medical centers – Stanford University Medical Center (California, USA) and Tel Aviv Medical Center (Israel) – between 2013 and 2016 were analyzed by an automatic four chamber volumetric analysis (4CVA) software, and grouped according to their RV volume index, into those with the largest RV (upper 5th percentile of RV volume index (&amp;gt;120 ml/m2; n = 16) versus those within the 95th percentile lower volumes index (≤120 ml/m2; n = 307). Differences in baseline characteristics between the groups were adjusted for with a propensity score. The risk for one year mortality following the TAVR was compared between the two groups. Results In total 323 patients were included. There were no major differences in background and demographic characteristics between the study groups. A significantly higher 1-year mortality rate was found for patients with large RV (31.3% vs. 7.5%, p = 0.008). After adjustment for clinical characteristics, patients with RV volume index &amp;gt;120 ml/m2 were at almost a 5 times higher risk for 1-year mortality compared to patients with smaller RV (HR 4.9, 95% CI 1.8-13.1, p = 0.002). The addition of echocardiographic parameters to the propensity score did not eliminate the significance of RV volume index &amp;gt;120 ml/m2 as an independent predictor for mortality at 1-year. An analysis of RV as a continuous variable demonstrated that the risk for 1-year mortality increased by 2% for every 1 ml/m2 RV volume enlargement (p = 0.013). Conclusions Cardiac volumetric data by CCTA performed for procedural planning may help predict outcome in patients undergoing TAVR. Abstract P1423 Figure. Cox survival curves according to RVi

Utility of pre-procedural CT and abdominal radiography before percutaneous radiologic gastrostomy placement.

To evaluate the utility of pre-procedural CT and abdominal radiography before percutaneous radiologic gastrostomy tube placement. A retrospective review of gastrostomy tube placements was conducted at a tertiary care radiology department. During the studied period, all percutaneous radiologic G-tube placements (PRG) at the institution required a pre-procedural abdominal CT. Whether the CT was interpreted to have an adequate window for PRG was recorded. The same patients with pre-procedural abdominal radiographs were also identified and retrospectively reviewed for the presence of satisfactory anatomy for PRG. Outcomes of tube placements were reviewed. 126 PRG requests were identified, all with abdominal CTs. 110 also had an abdominal radiograph. An adequate window for PRG was present in 83% of patients by CT and 73% by radiography. Of patients in whom it was attempted, 94% underwent successful PRG with a 7.4% minor complication rate. Of those refused for PRG based on CT, 9% had successful percutaneous endoscopic G-tube placement, resulting in a sensitivity of 98%. 97% of patients with satisfactory anatomy by radiograph underwent successful PRG. Of those with no window, 66% had a window by CT, and 94% in whom it was attempted had successful PRG placement. This resulted in a sensitivity of 77% for radiography. Concordance between CT and radiography was 73%. Pre-procedural CT interpretation is highly predictive of successful and uncomplicated PRG. Abdominal radiography also predicts successful PRG, but with a lower accuracy, limiting its utility as a pre-procedural exam.

Incremental Value of Aortomitral Continuity Calcification for Risk Assessment after Transcatheter Aortic Valve Replacement.

To investigate the association of aortomitral continuity calcification (AMCC) with all-cause mortality, postprocedural paravalvular leak (PVL), and prolonged hospital stay in patients undergoing transcatheter aortic valve replacement (TAVR). The authors retrospectively evaluated 329 patients who underwent TAVR between March 2013 and March 2016. AMCC, aortic valve calcification (AVC), and coronary artery calcification (CAC) were quantified by using preprocedural CT. Pre-procedural Society of Thoracic Surgeons (STS) score was recorded. Associations between baseline AMCC, AVC, and CAC and 1-year mortality, PVL, and hospital stay longer than 7 days were analyzed. The median follow-up was 415 days (interquartiles, 344-727 days). After 1 year, 46 of the 329 patients (14%) died and 52 (16%) were hospitalized for more than 7 days. Of the 326 patients who underwent postprocedural echocardiography, 147 (45%) had postprocedural PVL. The CAC score (hazard ratio: 1.11 per 500 points) and AMCC mass (hazard ratio: 1.13 per 500 mg) were associated with 1-year mortality. AVC mass (odds ratio: 1.93 per 100 mg) was associated with postprocedural PVL. Only the STS score was associated with prolonged hospital stay (odds ratio: 1.19 per point). AMCC is associated with mortality within 1 year after TAVR and substantially improves individual risk classification when added to a model consisting of STS score and AVC mass only.Supplemental material is available for this article.© RSNA, 2019See also the commentary by Brown and Leipsic in this issue.

Biopsy of Deep Pelvic and Abdominal Targets With Ultrasound Guidance: Efficacy of Compression.

OBJECTIVE. The purpose of this study was to evaluate the utility of compression of tissues with the ultrasound transducer in decreasing distance to the biopsy target and establishing a safe percutaneous biopsy route to deep abdominopelvic targets. MATERIALS AND METHODS. Ultrasound-guided biopsies of nonsolid organ abdominopelvic targets performed from 2006 to 2017 were reviewed. Skin-to-target distance was measured on preprocedure CT scans for reference standard and on procedure ultrasound images for actual real-time distance after compression. The skin-to-target CT distance groupings were 0-3 cm, 3-6 cm, 6-10, cm, and > 10 cm. Deep targets were defined as > 6 cm. Differences in skin-to-target distance between static CT and compression ultrasound were calculated. Body mass index, procedure details, diagnostic yield, and complication rate were recorded. RESULTS. The biopsies of 389 patients (167 men, 222 women; mean age, 62.4 years; mean body mass index, 28.2) were assessed. Skin-to-target distance was 0-3 cm in 108 patients, 3-6 cm in 163 patients, 6-10 cm in 99 patients, and > 10 cm in 19 patients. A total of 118 deep targets were identified. The mean skin-to-target distance in the entire cohort was 5.0 cm on CT scans and 3.6 cm on ultrasound images with a 10% mean decrease in distance with ultrasound compression. For skin-to-target distances of 6-10 cm, distance decreased 39% at ultrasound, and for skin-to-target distances > 10 cm, distance decreased 48%. Thirty-three patients (8.5%) had no safe identifiable path for CT biopsy, most commonly because of intervening bowel, displacement of which at ultrasound allowed a safe biopsy trajectory. Ultrasound-guided biopsy had a diagnostic yield of 91.5% and a favorable safety profile. The complication rate was 1.3%. CONCLUSION. Application of compression with the ultrasound transducer decreased skin-to-target distance 40% or more for deep targets in addition to displacing bowel and establishing a safe path for biopsy in approximately 8.5% of cases.

The region-of-interest based measurement selection process for electrical impedance tomography in radiofrequency cardiac ablation with known anatomical information

Radiofrequency (RF) cardiac ablation is a common technique for efficiently treating Cardiac Arrhythmias. However, the information of the dynamic lesion heating is still currently unavailable in a conventional catheterization laboratory. Electrical Impedance Tomography (EIT) is a temporal impedance imaging modality which might be able to track the heat-caused changes within the electrical property distribution of myocardium. Within this paper, a measurement selection process focusing on the region-of-interest (ROI), i.e. the ablated site, is proposed to deal with the EIT’s illposedness, the biggest obstruction to EIT’s feasibility this application. By gathering an adequate number of only high-sensitive measurements, the aim is to balance between the information need out of ROI and a well-posed EIT inverse solver. The process takes advantage of (1) known anatomical information due to preprocedural CT scans and (2) known intracardiac catheter location from electroanatomical mapping systems. The L2-norm of ROI conductivity changes was used to predict two lesion parameters including the depth and the width. A model was made including a 2.5D realistic thorax boundary and lungs, and an elliptical heart of 16 mm in thickness with 16 boundary electrodes and 3 internal catheter-based electrodes. 8 ablated positions were tested, in each one reference ablation for fitting the EIT-lesion size prediction curves and 100 testing ablations were simulated using the Pennes’ Bioheat transfer equation. Three disturbances including (1) varied myocardium conductivity, (2) varied blood flow convection effect and (3) catheter location mapping error, and the Gaussian noises up to 100 μV in standard deviation were introduced in the test. The results showed that, with no more than 12 measurements, EIT with the optimized measurement sets performed well when dealing with all three disturbances while allowing acquiring a high image rate in short time to flatten the noise up 100 μV.

Quantitative Pretreatment CT Parameters as Predictors of Tumor Response of Neuroendocrine Tumor Liver Metastasis to Transcatheter Arterial Bland Embolization

Purpose: To assess whether parameters on preprocedural CT can be utilized to predict the response of NETLM to transcatheter arterial bland embolization (TAE). Methods: We retrospectively reviewed 135 target lesions from 48 NETLM patients who underwent TAE and with complete preprocedural multiphasic CT. Parameters on preprocedural CT including the longest diameter, mean attenuation value in nonenhanced, arterial, and portal-venous phases were collected from each target lesion. Radiological responses were assessed according to RECIST 1.1. The parameters of responder lesions and nonresponder lesions were compared. Arterial enhancement index (AEI) and portal-venous enhancement index (PEI) were calculated. The predictive function of AEI and PEI on tumor response was analyzed by receiver operating characteristic (ROC) curve. Results: A total of 72.6% target lesions had a partial response. For patients, the objective response rate was 72.9%. Mean attenuation values of responder lesions were significantly higher than nonresponder lesions in both arterial and portal-venous phases (105.36 ± 37.24 vs. 76.01 ± 19.19, p < 0.001; 96.61 ± 24.04 vs. 82.12 ± 21.37, p = 0.002). ROC curve showed that both AEI and PEI were effective in predicting tumor response (area under the curve [AUC] 0.757, p < 0.001; AUC 0.655, p = 0.005). Conclusion: AEI and PEI, parameters from evaluation of CT pretreatment attenuation of NETLMs, could predict response to TAE treatment.

Feasibility of Yttrium-90 Radioembolization Dose Calculation Utilizing Intra-procedural Open Trajectory Cone Beam CT.

Dose calculation for transarterial radioembolization (TARE) with glass yttrium-90 (Y90) labeled microspheres is based on liver lobe and tumor volumes, currently measured from preprocedural MRI or CT. The variable time between MRI and radioembolization may not account for relevant tumor progression. Advances in cone beam computed tomography (CBCT) allow for intra-procedural assessment of these volumes that avoids this factor. Liver lobe and hepatocellular carcinoma tumor volume measurements and dose calculations using intra-procedural CBCT were compared to those using preprocedural MRI in order to determine feasibility. Retrospective analysis was performed in 20 patients with proven hepatocellular carcinoma (HCC) who underwent planning angiography with open trajectory CBCT acquisitions prior to radioembolization, and an MRI performed within 6 weeks prior to treatment planning. Liver lobe and tumor burden volumes were measured based on CBCT using embolization planning and guidance software and measured on preprocedural MRI using standard volume analysis software. Y90 doses were subsequently calculated using each measured volume. Comparisons of volume measurements and calculated Y90 doses between the two modalities were evaluated for significance using paired t tests. All target liver lobes and all tumors were completely depicted on CBCT. Mean liver lobe and tumor burden volumes measured on intra-procedural CBCT and preprocedural MRI showed no significant difference (p = 0.71). Mean calculated Y90 dose based on each modality showed no significant difference (p = 0.18). Lobar and tumor volume measurement with CBCT is a reliable alternative to measurement with preprocedural MRI. Utilization of CBCT 3D segmentation software during planning angiography may be useful to provide up-to-date volume measurements and dose calculations prior to radioembolization.

Cardiac CT and Structural Heart Disease Interventions (Non-TAVI)

The use of cardiac CT is well established in the TAVR sphere and gaining traction as an integral part of pre-procedural planning for left 13 atrial appendage closure (LAAC) and transcatheter mitral valve replacement (TMVR. We aim to review the recent evidence regarding the accuracy of cardiac CT for left atrial sizing and device selection and discuss the contribution of cardiac CT to decreasing complication rates in real-world experience as compared with clinical trials. Pre-procedural CT imaging has evolved to become an integral part of LAA closure and TMVR. For LAA closure, CT imaging provides detailed anatomic assessment of the LAA and surrounding structures and accurate measurements for device sizing. These can facilitate device and equipment selection and enhance safety and outcomes with intraprocedural guidance with transesophageal echocardiography or intracardiac echocardiography. For TMVR, pre-procedural CT is necessary to assess the potential risk of LVOT obstruction and determine device sizing. Such assessments can help pre-plan the potential need for adjunctive strategies to lower the risk of LVOT obstruction. CT imaging has gained important roles in the field of structural interventions, and understanding how to utilize this tool is an important skill to acquire as a contemporary comprehensive interventionist. Pre-procedural CT imaging has evolved to become an integral part of LAA closure and TMVR.

P3804Left ventricular wall thickness measured with computed tomography predicts mitral regurgitation improvement in patients implanted with cardiac resynchronization therapy

Abstract Background Secondary mitral regurgitation (MR) is common in heart failure (HF) patients and results in progressive left ventricular (LV) dilatation, papillary muscle (PM) displacement and mitral valve leaflet tethering. In selected HF patients, cardiac resynchronization therapy (CRT) has been proved to reduce MR by LV reverse remodeling, resynchronization of PM insertion site contraction and reduction in MV tenting area and inter PM distance. However, data regarding the impact of LV wall thickness (WT) on MR improvement are scarce. Methods In this prospective study, a total 54 patients scheduled for CRT, underwent pre procedural CT. Reduced LV WT was defined as WT&lt;6mm and was quantified as a percentage of total LV area. LV was segmented in 17 segments to assess the number of LV segments with reduced WT. End point was 6-month echocardiographic MR improvement by ≥1 class. For this analysis, we focused on patient with mild (class 2) to severe (class 4) MR. Results Among the 54 patients, 38 (70.4%) had mild to severe MR at baseline and a total of 16 (42.1%) experienced MR improvement by ≥1 class at 6 months. there was no difference regarding the co-morbidities, electrocardiogram and echocardiographic parameters between patients with or without MR improvement. However, patients without MR improvement had significant higher NT-pro BNP level at baseline. Interestingly, patients without MR improvement had larger LVWT &lt;6mm area (41.541.5±19.4 vs. 22.4±16.1%, p=0.003) associated with higher number of papillary muscle (PM) inserted in reduced LV WT area. In multivariate analysis, an area ≥25% of LVWT&lt;6mm including at least 1 PM insertion was the only predictor of no MR improvement at 6 months (HR 18.4 (1.25–271.75), p=0.034). Lastly, patients with MR improvement had significant lower rate of basal segments with reduced WT, especially in the lateral location. Of note, patients with MR improvement exhibited fewer rate of postero-lateral WT &lt;6mm segments. Left ventriculat segmentation Conclusion LV WT evaluated using CT is a strong predictor of no MR improvement in HF patients with mild to severe MR and who scheduled for CRT implantation.

2142 Endoscopic Management Cases for Small Bowel Obstruction

INTRODUCTION: Small bowel obstruction (SBO) is a common disease in the gastrointestinal surgery field. Although causes of SBO are highly variable, surgical management is usually selected for adhesive obstruction if nasogastric tube decompression has failed. There have been no reports of endoscopic cure for SBO, despite several reports of endoscopic management of colonic voluvulus or malignant colonic obstruction. Here we report three cases in which endoscopic reduction was safely performed for SBO. CASE DESCRIPTION/METHODS: Case1: An 86-year-old woman developed obstruction one month after right hemicolectomy for colorectal cancer. Preprocedural CT scan imaging detected a lumen caliber change near the ileocolonic anastomosis, and no recovery sign was acquired even after decompression treatment by nasogastric tube for 3 days. Colonoscopy with fluoroscopy showed ileum kinking at 10 cm proximal from the anastomosis. Case2: A 68-year-old woman developed obstruction during hospitalization for myelodysplastic syndrome. She had past surgcal history of 7 caesarean sections. Preprocedural CT scan imaging showed terminal ileum with transition point at 20 cm from ileocecal valve. Colonoscopy was performed after one week of conservative management. Colonoscopy with fluoroscopy revealed strong angulation and stricture accompanied by ulcerations at the terminal ileum. Case3: A 79-year-old woman developed obstruction one year after cystectomy with Indiana pouch reconstruction for bladder cancer. There was no improvement sign after 5 days of nasogastric tube and supportive treatment. Colonoscopy with fluoroscopy revealed ileum kinking 20 cm proximal to the ileocolic anastomosis, consistent with preprocedural imaging. In all 3 cases, the scope passed through the obstruction site following insertion of a guide wire and stiff catheter through above the obstruction area. All obstructions were successfully released. The passage of the contrast intraoperatively through the site was clearly observed. In Case 3 was added balloon dilation after the endoscope withdrawal. All patients were discharged without additional surgery or postprocedural complications, with 1.5-4 months follow up. DISCUSSION: We report three cases in which endoscopic treatment safely treated for SBO likely due to adhesions. Endoscopic management could release the obstruction earlier than predictable course in these three cases. These cases show the potential for endoscopic treatment to replace surgical treatment in a certain type of SBO.