Preprocedural MRI Research Articles

Impact of adjacent thoracic structures in negative left atrial remodelling in atrial fibrillation

Abstract Background Previous work has suggested that compression from external structures can promote negative atrial remodelling in atrial fibrillation (AF) [1]. This is mechanistically plausible, with many recognised risk factors in developing AF (age, hypertension, obesity, obstructive sleep apnoea, etc.) related through activation of the autonomic nervous system with an associated increase in atrial pressure and chronic elevation in wall stress [2,3]. Such negative remodelling contributes to the existence of arrhythmogenic atrial substrate [4]. This is highly significant when we consider catheter ablation of extrapulmonary vein targets. Purpose This study aims to investigate the relationship between abnormal conduction patterns indicative of potential AF drivers and their proximity to structures adjacent to the left atrium (LA). Methods Eight patients with paroxysmal or persistent AF, scheduled for an elective catheter ablation procedure using a charge density mapping (CDM) system [5] underwent pre-procedural cardiac MRI. 3D surface mesh reconstructions of individuals’ LA and adjacent structures (ascending aorta [AoA], descending aorta [AoD], and spine) were produced from 2D MRI slices using a proprietary graphical interface tool developed in MATLAB (Figure 1A & B) [6]. MRI derived LA geometries were registered with their CDM counterparts by the Iterative Closest Point algorithm (Figure 1C); this enabled integration of MRI LA geometries into the CDM system. Subsequently, non-contact intrachamber voltage measurements from individuals’ procedures were used to derive cardiac activation directly onto MRI LA geometries. Abnormal conduction patterns representing possible AF drivers (focal firing, rotational propagation, and pivoting propagation) [5] were quantified as occurrences per second at each vertex of MRI LA geometries (Figure 1D). These conduction patterns could then be visualised and assessed in the context of adjacent structures (Figure 1E), with the Euclidean distance between each vertex of the MRI LA geometries and the closest point to their adjacent structures being calculated. Results Mean age was 65±9 years; 4 patients (50%) were male; AF was paroxysmal in 3 (37%) and persistent in 5 (63%); median time since AF diagnosis was 1 (1-3.8) years; ablation type was de novo in 5 (63%) and retreatment in 3 (38%). Frequencies of pivoting and rotational propagation were notably higher in regions of the LA closer to the AoA, and lower near the AoD and spine (Figure 2A & B). Conversely, focal firing showed a less prominent trend, being more frequent in LA regions nearer the AoD and distant from the AoA (Figure 2C). Conclusions Compression from the ascending aorta may promote anterior LA remodelling in AF, leading to increased pivoting and rotational AF drivers. Clinically, this suggests a potential target for ablation therapy with an anterior seatbelt line connecting the right superior pulmonary vein to the mitral annulus.

The Incidence and Risk Factors for the Presence of Type 1B or Type 3 Utero-ovarian Anastomoses During Uterine Artery Embolization

Background/Aims: Demonstration of possible utero-ovarian anastomoses (UOA) before or during uterine artery embolization (UAE) is important to preserve ovarian reserve. This study aimed to evaluate the incidence and risk factors for the presence of type 1b or type 3 UOA in patients undergoing UAE for the treatment of uterine myomas. Methods: Procedural angiographies of patients who underwent UAE were evaluated in a single academic center. Patients’ demographics, indication for UAE, presence and type of UOA, presence of adnexal pathology at preprocedural MRI, history of pelvic surgery, and total uterine volume at preprocedural MRI were retrospectively evaluated. Analysis of the aforementioned variables between patients with and without UOA was performed. Results: This study included 30 patients with a mean age of 41.97±5.72 years (range 32 - 56). UOA was found in 17 (56.6%) patients, 10 (33.3%) of them were type 1b, and 7 (23.3%) of them were type 3. Five patients (17.2%) had adnexal pathology at pre-procedural MRI and 12 patients (40%) had a history of pelvic surgery. The mean total uterine volume was 607.1 cm3. In the analysis of variables between patients with and without UOA, UOA presence was significantly higher in patients with a history of pelvic surgery (p=0.005). All of the patients with a history of myomectomy were found to have type 1b or type 3 UOA. No significant relation between UOA and age, the presence of adnexal pathology, and uterine volume were detected. Conclusion: Utero-ovarian anastomoses are commonly encountered during UAE. A history of pelvic surgery was found to be a risk factor for the presence of type 1b and type 3 UOA.

Comparing magnetic resonance imaging and ultrasound in the clinical evaluation of fibroids prior to uterine artery embolization

PurposeUterine artery embolization has become established as a frontline treatment for uterine leiomyomata. In planning embolization, preprocedural imaging can further characterize pathology and anatomy, but it may also reveal coexisting diagnoses that have the potential to change clinical management. The purpose of this study is to compare the diagnostic outcomes of ultrasound and MRI performed for patients prior to undergoing embolization. MethodsThe study cohort consisted of 199 patients who underwent uterine artery embolization at a single academic institution between 2013 and 2018. Prior to embolization, all patients had an MRI confirming a leiomyomata diagnosis. Additionally, 118 patients underwent transvaginal ultrasound within five years prior to MRI. MRI findings were analyzed and, when applicable, compared to prior ultrasound impressions to assess for the incidence of new findings. The diagnoses of interest were adenomyosis, hydrosalpinx, predominantly infarcted leiomyomata, and large intracavitary leiomyomata. Data were collected from retrospective chart review and included demographics, symptomology, and imaging reports. Results199 patients ultimately underwent embolization for treatment of MRI-confirmed leiomyomata. Of 118 patients who also had an ultrasound within five years prior to their MRI, 26 (22.0%) received a second gynecologic diagnosis based on MRI findings that was not previously seen on ultrasound. Of 81 patients who only had an MRI before embolization, 19 (23.5%) received a second gynecologic diagnosis not previously documented. The most common coexisting pathology was adenomyosis, presenting in 34 (17.1%) patients with leiomyomata, followed by large intracavitary leiomyomata (8, 4.0%), infarcted leiomyomata (7, 3.5%), and hydrosalpinx (6, 3.0%),. ConclusionsWhen considering uterine artery embolization for the treatment of symptomatic leiomyomata, preprocedural MRI is superior to ultrasound in detecting coexisting pathologies, including adenomyosis and hydrosalpinx. It can also better characterize leiomyomata, including identifying lesions as intracavitary or infarcted. These findings have the potential to alter clinical management or contraindicate embolization entirely.

Use of percutaneous imaging-guided biopsy for Liver Imaging and Reporting Data System (LI-RADS) observations: A retrospective study from two liver transplant centers

Since the adoption of guidelines for the non-invasive imaging diagnosis of hepatocellular carcinoma (HCC), the need for sampling of a lesion in cirrhosis has decreased. We aimed to retrospectively investigate the use of percutaneous imaging-guided biopsy for LI-RADS observations in cirrhosis in two large liver transplant centers. A review of the pathology database in the two Institutions (Institution A, Institution B) was conducted to identify patients that underwent percutaneous imaging-guided biopsy for a liver lesion in the interval time 01/01/2015-12/312020. Liver observations on pre-procedure contrast-enhanced CT or MRI were classified according to LI-RADS v2018. Among the 728 patients who underwent imaging guided biopsy of a liver lesion in Institution A, and among the 749 patients who underwent imaging guided biopsy of a liver lesion in Institution B, respectively 50 (6.8 %) and 16 (2.1 %) were cirrhotic with available pre-procedural contrast-enhanced CT or MRI. A total of 67 lesions were biopsied. 30/67 (45 %) biopsied observations were classified as LR-M. 55/67 (82 %) biopsies were positive for malignancy at histopathology and among them 33 (60 %) were HCC. In conclusion, a small percentage of percutaneous, imaging-guided biopsies for liver lesions are performed in cirrhosis, and more frequently for LR-M observations.

Multi-modal characterization of the left atrium by a fully automated integration of pre-procedural cardiac imaging and electro-anatomical mapping

BackgroundThe combination of information obtained from pre-procedural cardiac imaging and electro-anatomical mapping (EAM) can potentially help to locate new ablation targets. In this study we developed and evaluated a fully automated technique to align left atrial (LA) anatomies obtained from CT- and MRI-scans with LA anatomies obtained from EAM. MethodsTwenty-one patients scheduled for a pulmonary vein (PV) isolation with a pre-procedural MRI were enrolled. Additionally, a recent computed tomography (CT) scan was available in 12 patients. LA anatomies were segmented from MRI-scans using ADAS-AF (Galgo Medical, Barcelona) and from the CT-scans using Slicer3D. MRI and CT anatomies were aligned with the EAM anatomy using an iterative closest plane-to-plane algorithm. Initially, the algorithm included the PVs, LA appendage and mitral valve anulus as they are the most distinctive landmarks. Subsequently, the algorithm was applied again, excluding these structures, with only three iterative steps to refine the alignment of the true LA surface. The result of the alignments was quantified by the Euclidian distance between the aligned anatomies after excluding PVs, LA appendage and mitral anulus. ResultsOur algorithm successfully aligned 20/21 MRI anatomies and 11/12 CT anatomies with the corresponding EAM anatomies. The average median residual distances were 1.9 ± 0.6 mm and 2.5 ± 0.8 mm for MRI and CT anatomies respectively. The average LA surface with a residual distance less than 5.00 mm was 89 ± 9% and 89 ± 10% for MRI and CT anatomies respectively. ConclusionAn iterative closest plane-to-plane algorithm is a reliable method to automatically align pre-procedural cardiac images with anatomies acquired during ablation procedures.

Comparison of zero fluoroscopy versus fluoroscopy guided ablation for atrial fibrillation: A single center experience

Abstract Funding Acknowledgements Type of funding sources: None. Background With advances in mapping equipment and increased use of intracardiac echocardiography (ICE), atrial fibrillation (AF) ablations can be safely performed without fluoroscopy. Benefits include no radiation exposure to patient and staff and reduced long-term orthopedic complications related to use of lead aprons for staff. Published data comparing zero fluoroscopy ablation (ZFA) and conventional fluoroscopy guided ablation (CFA) for AF is limited to small case series and meta-analysis. Aim To evaluate the safety and procedural outcomes of a simplified ZFA approach, comparing it to standard of care (CFA). Methods Consecutive AF cases from 03/2021 to 09/2022 at our institution were included. 120 cases underwent ZFA (RF ablation, ICE and 3D mapping guided) and 155 cases underwent CFA (Cryo or RF ablation, fluoroscopy, ICE and 3D map guided). For the ZFA group, a simplified ICE based map of relevant anatomical structures was created, in order to guide trans-septal (TS) access and left -sided ablation (See figure) and no pre-procedural imaging was obtained. All CFA cases had pre-procedural cardiac CT or MRI to evaluate left atrial anatomy. Redo ablation cases represented 17% of the ZFA and 23% of the CFA patients. All cases were performed by operators with >12 years of experience, and all cases underwent general anesthesia. Only two ZFA cases required a brief period of fluoroscopy (under 2 min each) to achieve safe trans-septal access (including one case with a prior ASD closure device). Results Mean age was 67 for ZFA and 69 for CFA groups respectively (p=NS). 69% of ZFA and 71% of CFA cases were men. Persistent AF cases more frequently underwent posterior wall isolation in the ZFA group (98% vs 68%, P<0.01), but despite this, procedural times were similar for both groups (168±55 min ZFA vs 172±51 min CFA, P=NS). Procedural success (pulmonary vein isolation ± posterior wall isolation) was achieved in all ZFA and 99% of CFA cases. At a mean follow up 12 months, Freedom for AF was 81% for paroxysmal AF and 74% for persistent AF cases in the ZFA group, and 79% for paroxysmal AF cases and 71% for persistent AF cases in the CFA group (p=NS). Procedural complications included one TIA in the ZFA group and 2 pericardial effusions in the CFA group (p=NS). Use of antiarrhythmic drugs post ablation did not differ between the ZFA and the CFA groups (23% vs 27%, p=NS). Conclusion Our ZFA approach for AF was safe, effective and produced similar outcomes compared to a traditional CFA approach. ZFA has considerable health benefits for personnel and patients without compromising procedural outcomes. The cost of ICE catheters may be offset by eliminating the need for pre-procedural imaging (CT or MRI) commonly used prior to AF ablations. Our study adds to the growing literature supporting the safety of catheter ablation in a non-fluoroscopy environment.

PO-02-121 IMPACT OF PULMONARY VEIN OVALITY AND OCCLUSION STATUS MEASURED BY THE NOVEL DIELECTRIC-BASED MAPPING SYSTEM ON ACUTE VEIN ISOLATION DURING CRYOBALLOON ABLATION

Cryoballoon ablation (CBA) has been widely accepted as a major technic for pulmonary vein isolation (PVI) in patients with atrial fibrillation (AF). PV anatomy is an important factor to obtain circumferential balloon adhesion that results in vein occlusion to achieve acute PVI. The KODEX-EPD (Philips, Amsterdam, Netherlands) is a dielectric-based electroanatomic mapping system that can display a panoramic (PANO) view of the left atrium and evaluate PV occlusion without other imaging modalities. Prior studies demonstrated that high PV ovality is the potential mechanism of impeding the formation of durable lesion. However, the accuracy of PV ovality assessed by KODEX-EPD system and how it influences the performance of the PV occlusion tool and acute PVI are still unknown. To assess the PV occlusion and PV ovality using the KODEX-EPD system, and to evaluate the accuracy of them and their impact on acute PVI. We enrolled 10 patients who underwent primary CBA for paroxysmal AF using KODEX-EPD system, all of them had a pre-procedural cardiac CT or MRI. Ovality index (OI) was defined as the ratio of the PV maximum diameter divided by PV minimum diameter which was measured by KODEX-EPD system under PANO view and on CT/MRI images under sagittal view. An evaluation of PV occlusion was obtained using the KODEX-EPD Occlusion Viewer and intracardiac echography on each CB-PV engagement. Single shot PVI was defined as the isolation of PV at the first freezing attempt after complete occlusion of the PV. Fifty-eight balloon-PV engagements in 39 PVs were analyzed. Consistent occlusion status between KODEX and ICE were obtained in 50 (86%) engagements [complete occlusion: 30/34 (88%), incomplete occlusion 20/24 (83%)]. The OI of PV with incomplete occlusion by KODEX is significantly larger than that with complete occlusion (2.0±0.5 vs 1.6 ±0.4. p=0.03). Representative cases are shown in Figure1A and B. Single shot PV isolation was achieved in 33 of 39 PVs (84%). All of them showed complete occlusion status in KODEX, and OI of PV with single shot isolation was significantly smaller than that without single shot isolation (1.6±0.4 vs 2.1±0.4, p=0.003). A positive correlation was found between the OI measured by KODEX and CT/MRI (Figure1C). The evaluation of PV anatomy and occlusion status using the novel dielectric-based mapping system is feasible and may facilitate CB ablation of AF. Higher PV ovality is associated with incomplete PV occlusion and lower acute PVI rate.

Advanced Imaging Integration for Catheter Ablation of Ventricular Tachycardia.

Imaging plays a crucial role in the therapy of ventricular tachycardia (VT). We offer an overview of the different methods and provide information on their use in a clinical setting. The use of imaging in VT has progressed recently. Intracardiac echography facilitates catheter navigation and the targeting of moving intracardiac structures. Integration of pre-procedural CT or MRI allows for targeting the VT substrate, with major expected impact on VT ablation efficacy and efficiency. Advances in computational modeling may further enhance the performance of imaging, giving access to pre-operative simulation of VT. These advances in non-invasive diagnosis are increasingly being coupled with non-invasive approaches for therapy delivery. This review highlights the latest research on the use of imaging in VT procedures. Image-based strategies are progressively shifting from using images as an adjunct tool to electrophysiological techniques, to an integration of imaging as a central element of the treatment strategy.

Prevention of in-stent restenosis with drug-eluting balloons in patients with postirradiated carotid stenosis accepting percutaneous angioplasty and stenting

ObjectiveTo investigate the technical safety and outcome of in-stent restenosis (ISR) prevention with drug-eluting balloon (DEB) in patients with postirradiated carotid stenosis (PIRCS) undergoing percutaneous angioplasty and stenting (PTAS).MethodsBetween 2017...

CT-guided ozone mixture injection in treatment of symptomatic lumbar facet synovial cysts.

To evaluate the clinical and radiological outcomes, in terms of safety and efficacy, of a new treatment method for symptomatic lumbar facet synovial cysts (LFSC), based on ozone injection inside the cyst. We retrospectively reviewed clinical records and imaging studies of 77 patients who underwent CT-guided ozone treatment of symptomatic facet joint synovial cysts in our department over a 5-year span. Clinical outcome was assessed with Numerical Rating Scale (NRS) and Oswestry Disability Index (ODI) evaluations, obtained prior to the intervention and at 1-, 3-, 6- and 12-months follow-up. Follow-up MRI imaging at 6 and 12 months were obtained and confronted with the pre-procedural MRI to analyse cyst modification after the intervention. Ozone administration was technically successful in 100% of procedures; no immediate complications occurred. At 1 month evaluation, 92% of the patients referred partial or complete symptomatic response; 86% of patients at 3 months and 84% at 6 months confirmed symptoms improvement; final assessment, at 12 months after intervention, outlined overall significant clinical improvement in 81% of patients. During the 12 months of follow-up only 3 patients had a relapse of the cyst (at 6 months) that were retreated with a 100% success. CT-guided ozone therapy for symptomatic LFSC is a safe and innovative treatment option, with good clinical results at 12 months follow-up in a significative percentage of patients, thus reducing the need for invasive surgical interventions.

3D-PRINTING FOR ABLATION PLANNING IN PATIENTS UNDERGOING ATRIAL FIBRILLATION ABLATION (3D-GALA TRIAL)

Objective: Atrial fibrillation (AF) remains one of the major causes of cardiovascular morbidity. Ablation techniques are becoming more appealing after latest results of andomised trials showing the overall clinical benefit. On the other hand imaging techniques and the frontier application of 3D printing are emerging as valuable ally for cardiac procedures. However, no andomised trial has directly assessed the impact of preprocedural imaging and especially 3D printing guidance for AF ablation. The present study is designed to investigate for the first time the effect of 3D-printing of the heart on the safety and effectiveness of the ablation procedure. Design and method: The 3D-GALA trial is a andomised, open- label, controlled, multicentre clinical trial of 2 parallel groups designed to enrol a total of 100 patients undergoing ablation using cryo-balloon for paroxysmal and persistent AF. Patients will be andomised with a patient allocation ratio of 1: 1 to preprocedural MRI scan of the heart and 3D printing of left atrium and pulmonary veins and cryoablation versus standard cryoablation without imaging. Patients will be followed up to 6 months after the index procedure Results: The primary outcome measure is the reduction of radiation dose and contrast amount during pulmonary veins isolation. Secondary endpoints will include the percentage of atrial fibrillation relapse at 24h-Holter electrocardiogram monitoring at 6 months after initial treatment. Conclusions: To our knowledge, the 3D-GALA trial will be the first study to provide evidence about the clinical impact of preprocedural imaging and 3D printing before cryoablation.

Lateral decubitus dynamic CT myelography for fast cerebrospinal fluid leak localization.

Dynamic CT myelography is used to precisely localize fast spinal CSF leaks. The procedure is most commonly performed in the prone position, which successfully localizes most fast ventral leaks. We have recently encountered a small subset of patients in whom prone dynamic CT myelography is unsuccessful in localizing leaks. We sought to determine the added value of lateral decubitus dynamic CT myelography, which is occasionally attempted in our practice, in localizing the leak after failed prone dynamic CT myelography. We retrospectively identified 6 patients who underwent lateral decubitus dynamic CT myelography, which was performed in each case because their prone dynamic CT myelogram was unrevealing. Two neuroradiologists independently reviewed preprocedural spine MRI and all dynamic CT myelograms for each patient. Lateral decubitus positioning allowed for precise leak localization in all 6 patients. Five of six patients were noted to have dorsal and/or lateral epidural fluid collections on spine MRI. One patient had a single prominent diverticulum on spine MRI (larger than 6mm), whereas the others had no prominent diverticula. Our study suggests that institutions performing dynamic CT myelography to localize fast leaks should consider a lateral decubitus study if performing the study in the prone position is unrevealing. Furthermore, the presence of dorsal and/or lateral epidural fluid collections on spine MRI may suggest that a lateral decubitus study is of higher yield and could be considered initially.

Development and validation of a fully automatic algorithm to align 3D MRI and electro-anatomical mapping anatomies of the left atrium

Abstract Funding Acknowledgements Type of funding sources: None. Background The role of pre-procedural cardiac imaging in the guidance and planning of ablation procedures is becoming increasingly important. Emerging non-invasive techniques such as late gadolinium enhancement magnetic resonance imaging (LGE MRI) and electrocardiographic imaging (ECGi) can potentially help to locate ablation targets prior to the ablation procedure. To be able to integrate LGE MRI and ECGi information into targeted ablation procedures, a reliable alignment between cardiac imaging and electro-anatomical mapping (EAM) is required. Purpose To develop and evaluate a fully automatic technique to align pre-procedural MRI anatomies with EAM anatomies of the left atrium (LA). Methods Twenty-one patients scheduled for a (re-do) pulmonary vein (PV) isolation with a 3D pre-procedural LGE MRI were enrolled in this study. LA anatomy was segmented from the MRI dataset using ADAS-AF. During the ablation procedure LA anatomy was recorded with an HD-grid (Ensite) or Pentaray catheter (CARTO). The MRI segmentation and EAM were performed by different cardiologists blinded for each other’s results. Anatomies of both MRI and EAM were aligned using an iterative closest point-to-plane algorithm in custom-made software in Matlab 2021a. With this algorithm, the distance between MRI anatomy voxels (=points) and the surface of the EAM anatomy (=plane) is minimized by translating and rotating the MRI anatomy until the total residual distance is minimized. The result of the alignment is quantified by calculating the Euclidian distance between the aligned anatomies after excluding PVs and the mitral anulus. Results The algorithm was successfully applied in 18/21 patients (n=11 CARTO, n=7 Ensite). In the remaining 3 patients, the algorithm could not align the anatomies because of a large difference in LA volume or PV anatomy between the two techniques. In the analysed patients, the average distance between anatomies was 2.7±0.77mm. The top of Figure 1 shows the alignment of the anatomies with the smallest (patient A) and the largest (patient B) residual distances as well as the distances between these anatomies for both patients (right) with purple ≤2.5mm and red ≥5.0mm. The distributions of distances (bottom left) show that, after alignment most of the MRI anatomy is closer than 5mm from the EAM anatomy in every patient. On average, 87.6±10.4% of the atrial surfaces showed distances below 5.0mm between the two anatomies and 55.1±13.2% of the surfaces was within 2.5mm from each other. Results did not differ between Ensite and CARTO anatomies. Conclusion LA anatomy obtained from 3D LGE MRI can automatically and reliably be aligned with LA anatomy recorded during an ablation procedure with an EAM system using an iterative closest point-to-plane algorithm.

Cervical spine ligamentum flavum gaps: MR characterisation and implications for interlaminar epidural injection therapy

BackgroundCervical epidural steroid injections are commonly performed to manage pain from cervical spine disease. Cadaveric studies have demonstrated incomplete ligamentum flavum fusion in the central interlaminar region with resultant midline...

P 23 The overlap of lesions placed by MRIgFUS with the cerebellothalamic tract does not adequately explain symptom control in ET

Background: The thalamic ventral intermediate (Vim) nucleus is part of a network that appears to be disrupted in essential tremor (ET) and is the most relevant target of functional neurosurgery to alleviate ET symptoms. As the most important afferent of the VIM, the cerebellothalamic tract (CTT) transmits information from cerebellar nuclei. Disruption of this tract - in the past via subthalatomies and in the present via deep brain stimulation is considered the best option of tremor treatment, partly because of the high anatomical density of CTT fibers before entering the VIM, and partly because of the greater distance to sensory thalamic nuclei. Recently, initial pilot studies have also documented transcranial MRI-guided high-intensity focused ultrasound (MRIgFUS) as an effective treatment modality. Unilateral MRIgFUS lesioning was highly efficacious in reducing contralateral hand tremor in ET with mild and transient adverse effects. However, targeting of MRIgFUS has so far been based on MRI imaging without dedicated evidence of the underlying connectome. Here, we test a method for quantitative analysis of the involved fiber tracts and test whether the measured clinical effect correlates with overlap of the set lesion with individual fiber tracts, such as CTT. Materials and Methods: We revisited pre- and post-procedural MRIs of 6 ET patients (Øage 70,7 (± 8,5) years , Ø Tremor rating (TR) (pre): 43,8 (± 9,8)) who underwent unilateral ablation of the CTT by MRIgFUS. The images, obtained 48 hours (48H) and 3-6 months (3M+) after the procedure, were used to create 3D-models of the lesions which were localized within MNI-space with the pre-procedural MRI and atlas registration using Suretune®. The models were subsequently used to calculate interferences with fiber tracts. A linear model was employed to assess the correlation between the quantitative interference and improvement of the clinical score at two timepoints after the procedure (48H, n=6: TR: 16,7 (±5,5) ; 3M+, n= 5: TR: 19,2 (±7,2)). Results: The lesions volume differed between the 48H (Ø 281.78mm3(±77.77), n=6) and 3M+(Ø 53.82mm3(±22), n=5) conditions (p<0.01). After 48H primarily the CTT (Ø72,4 % (±34)) but also the M1 (Ø36,05 % (±43)) interfered, while after 3M+ the overlap reduced tremendously for the CTT (Ø1% (±1,6), p=0.017) and slightly for the M1(Ø26,7% (±28,4), p=0.67). Preliminary results could not show a correlation between the observed clinical improvement with the interference of the lesions with a specific tract. Discussion: Interestingly, there is no clear correlation between clinical outcome and the overlap between the lesion placed by MRIgFUS and the fibers of the CTT. This might indicate that the observed clinical effect would have to be explained only partially by the targeted CTT but also by other fiber tracts. The data set was too small for a meaningful multivariate regression analysis, but pooling data sets from different centers may mean a solution to this problem in the future.

The incidence of lumbar spine surgery following Minimally Invasive Lumbar Decompression and Superion Indirect Decompression System for treatment of lumbar spinal stenosis: a retrospective review.

Lumbar spinal stenosis affects more than 200,000 adults in the United States, resulting in approximately 38,000 operations among the Medicare population and greater than $1.5 billion in hospital bills alone. Fortunately, Minimally Invasive Lumbar Decompression (MILD) and the Superion Indirect Decompression System have shown lasting benefit and cost savings compared to more aggressive surgical options. Our primary objective was to retrospectively determine the rate of lumbar decompression surgery following the MILD and Superion procedures. This was a pooled retrospective review of LSS patients who received MILD and/or Superion procedures between January 2011 and July 2019. Adult patients with CPT codes for MILD and Superion procedures were identified. Patients were included if they had a follow-up visit at least 2years from the procedure date, preprocedural MRI results, and surgical notes. A total of 199 patients were included in the final analysis, of which 57 patients (28.6%) underwent MILD procedure only, 124 patients (62.3%) underwent Superion only, and 18 patients (9.0%) underwent an MILD procedure initially followed by a Superion procedure. Two patients had an MILD procedure performed twice at the same level at separate encounters. A total of four patients in the entire cohort (2.0%; MILD 5.3%, Superion 0.8%) underwent subsequent lumbar spine surgery when followed for at least 2years. It is notable that some of these patients may not have been surgical candidates and this may have skewed the results. Patients undergoing minimally invasive decompression treatment of lumbar spinal stenosis have low rates of subsequent open surgery which potentially results in cost savings and a reduction in severe adverse events. The reason for low surgical rate may reflect improvement in their symptoms, a preference to avoid surgery, or being deemed not a surgical candidate.

Transarterial Chemoembolization Of Hepatocellular Carcinoma: Can Early Diffusion Weighted Imaging Predict Response?

PURPOSE: We evaluated the role of early diffusion weighted imaging (DWI) in predicting response to TACE in patients with HCC and compare the results with contrast enhanced magnetic resonance imaging. Methods: 24 patients with documented HCC were taken up for TACE after a pre-procedural contrast CT and MRI. Post procedural DWI was taken on day 5-7 and the mean ADC values were documented and compared to pre procedural values. The change in ADC values was grouped into 4 categories: group 1- &lt;25%, group 2 26-50%, group 3- 51-75% and group 4- &gt;75%. The increase in ADC values signifying response was correlated with 5 week CEMRI scan (which has been the traditional gold standard for response evaluation) and a threshold ADC increase signifying response in majority of the cases was calculated. Results: The mean ADC of the lesions changed from 1.21× 10-3 (pre TACE) to 2.02× 10-3 mm2/sec (post TACE) [p&lt;0.001]. Taking CE MRI as gold standard, DWI imaging had a sensitivity of 80%, specificity of 94.7% with a positive predictive value of 80%, negative predictive value of 94.7% and overall accuracy of 91.7%. Complete response was seen in19 (79%) and incomplete in 5 (21%) patients in our study. The change in ADC was significantly higher in responders (884.15 ± 161.60) as compared to non responders (564.80 ± 221.05) [p =0.001]. Conclusion: Early DWI after TACE can predict response of a HCC lesion to chemoembolization. The change in ADC values can earmark responders from non-responders. Early DWI results are concordant with CEMRI results in most of the cases. DWI can act as a substitute to CEMRI when contrast administration is not advised.

Single Evaluation of Use of a Mixed Reality Headset for Intra-Procedural Image-Guidance during a Mock Laparoscopic Myomectomy on an Ex-Vivo Fibroid Model

Uterine fibroids represent the highest prevalence of benign tumors in women, with reports ranging from 4.5% to 68.6%, with a significant bias towards African American women. For uterine fibroids, a significant decision is determining whether fibroids can be successfully removed using minimally invasive (MI) techniques or their removal requires open surgery. Currently, the standard-of-care for intra-procedural visualization for myomectomies is ultrasound, which has low image quality and requires a specially trained assistant. Currently, the state-of-the-art is to obtain a pre-procedural MRI scan of the patient, which can be used for diagnosis and pre-procedural planning. Although proven incredibly useful pre-procedurally, MRI scans are not often used intra-procedurally due to the inconvenient visualization as 2D slices, which are seen on 2D monitors that do not intuitively convey the depth or orientation of the fibroids, as needed to effectively perform myomectomies. To address this limitation, herein, we present the use of a mixed reality headset (i.e., Microsoft HoloLens 2), as a tool for intra-procedural image-guidance during a mock myomectomy of an ex vivo animal uterus. In this work, we created a patient-specific holographic rendering by performing image segmentation of an MRI scan of a custom-made uterine fibroid animal model. A physician qualitatively assessed the usefulness of the renderings for fibroid localization, as compared to the same visualization on a 2D monitor. In conclusion, the use of mixed reality as an intra-procedural image guidance tool for myomectomies was perceived as a better visualization technique that could lead to improvements in MI approaches and make them accessible to patients from lower socioeconomic populations.

Correlation between Clinical Outcome Following Ultrasound-guided Steroid Injection in Retrocalcaneal Bursa and Preprocedural MRI Findings in Different Grades of Achilles Tendinitis

Correlation between Clinical Outcome Following Ultrasound-guided Steroid Injection in Retrocalcaneal Bursa and Preprocedural MRI Findings in Different Grades of Achilles Tendinitis

Can pre-procedural MRI signal intensity ratio predict the success of uterine artery embolization in treatment of myomas?

Background/aim Magnetic resonance (MR) images, signal intensity ratios calculated using region of interests (ROI) in T2W images by proportioning the dominant myoma to iliac muscle can aid patient selection and, thus, in achieving better outcomes with the uterine artery embolization (UAE) procedure. The present study investigates the association between the success of UAE treatment with signal intensity (SI) ratio of the dominant myoma to the iliac muscle in MR imaging performed prior to the procedure.Materials and methods This is a retrospective study and included 30 patients who admitted to our clinic between February 2017 and July 2019 due to symptoms associated with myoma and who underwent MR imaging before and after UAE treatment. All patients, MR images obtained before UAE treatment and at the 12th month after the procedure were evaluated. In MRI, SI values were calculated by proportioning the dominant myoma to the iliac muscle using circular ROI in T1 weighted (W), T2W, and post-contrast T1W images. In the present study, 50% or more volumetric regression of the myoma with infarction of fibroids (loss of enhancement) at the 12-month follow-up MRI after the procedure was considered a successful procedure. Results Myoma volumes calculated in MR images showed significant differences between the MRI performed before UAE procedure and the MRI performed at the 12th month after the procedure (p < 0.0001). SI ratio calculated from pre-procedure T2W MR images was found to be a significant determinant of 50% or more volumetric regression in the myoma after UAE procedure (p = 0.017), T1W, post-contrast T1W images were not statistically significant (p = 0.211).Conclusion Our results indicate that SI ratio of the dominant myoma to the iliac muscle calculated using ROI in T2W images of MR studies performed before UAE procedure can predict the success of the procedure.