Preprocedural Magnetic Resonance Imaging Research Articles

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.

P4652Magnetic resonance and electroanatomical guided endomyocardial biopsy as a diagnostic tool in the clinician's box: a 5 year experience

Abstract Background Percutaneous endo-myocardial biopsy (EMB) is an invasive diagnostic test used to reach or confirm a diagnosis when structural or substrate anomalies are suspected, such as in cardiomyopathies or myocarditis evaluation. In recent years, cardiac magnetic resonance imaging (MRI) and endo-cavitary electro-anatomical mapping (EAM) have been used to localize the most significant myocardial area to sample, therefore increasing EMB overall effectiveness and reliability. Purpose To describe and characterize safety, feasibility and anatomical findings of a large cohort of patients (pts) undergoing diagnostic EMB and to assess its impact on the treatment decision making algorithm. Methods A cohort of all pts undergoing a percutaneous EMB at our Institution from January 2014 to January 2019 was analyzed. All EMB procedures were guided by a pre-procedural cardiac MRI radiological alteration analysis and an endo-cavitary EAM. Intra-cardiac echography (ICE) was used in all procedures, to directly visualize the sample area and to evaluate in real time post-EBM complications. Demographics, clinical data, MRI data, pathological EMB features, and peri-procedural data were systematically retrieved. Results One-hundred and eleven pts were enrolled (78% male, 47±4 y.o., 33% athletes). EMB indication was abnormal MRI findings in 94 (85%), pathological EMB voltages in 10 (9%) and clinical suspect and patient history in 7 (6%) pts. EMB sample area was determined by both MRI and EAM pathological area analysis in 92 (83%) pts, while by EAM alone in 19 (17%) pts (n=6 pathological unipolar EAM; n=13 bipolar and unipolar pathological EAM). The sample site was the right ventricle in 89 (80%), the left ventricle in 20 (18%), and both in 3 (2%) pts. In 103 (93%) pts a concomitant electrophysiological induction study was performed (40% positive for sustained ventricular arrhythmias) and 35 (32%) pts underwent a trans-catheter ablation (TCA) (n=8 epicardial TCA; n=2 endo-epicardial TCA; n=25 endocardial ATC). Only 2 (2%) peri-procedural adverse events were witnessed, specifically femoral pseudo-aneurysms, requiring surgical repair. EMB analysis allowed to confirm 58 (52%) pre-procedural diagnosis and to reach 32 (29%) new diagnosis, while resulting inconclusive or non-specific in the diagnostic process only in 21 (19%) cases [Figure1]. A total of 33 (30%) intra-cardiac devices (ICDs) were implanted contextually in the cohort, of which 9 (8%) solely upon EMB indication; in 4 (4%) other patients, biopsy represented a strong decisional factor in the multi-modality decision process for abstaining from ICD implant. Dashed lines: diagnosis changed upon EMB Conclusion MRI and EAM guided EMBs allowed to finely define a large cohort of patients by representing a disease defining parameter in over 80% of the enrolled pts while and a decision shifting parameter in ICD implant algorithm in a high % of pts.

DEPTH ASSESSMENT USING CONTRALATERAL OBLIQUE VIEW DURING CERVICAL INTERLAMINAR EPIDURAL STEROID INJECTIONS

Background: Recent literature has demonstrated that the contralateral oblique (CLO) view provides a more reliable angle in determining needle depth when compared to the lateral view during cervical interlaminar injections. Despite the utilization of CLO safety views, contrast patterns, and loss-of-resistance techniques, inherent risk of injury still remains. Additional safety measures must be assessed to provide clinicians with further safeguards to prevent procedural complications. Objective: The purpose of our study is to provide a reliable method of gauging needle depth insertion during cervical interlaminar injections by comparing the distance from the skin to the epidural space when measured on magnetic resonance imaging (MRI) and when measured intraoperatively. Methods: The study sample included 45 patients with cervical radiculopathy or cervical spinal stenosis. The distance from the skin to the epidural space was measured on cervical spine MRI and with the spinal needle intraoperatively. Primary analysis included the correlation between these distances, and whether differences in depth were influenced by injection level, needle tip location, or body mass index (BMI). Results: A significant correlation (r = .975, P < .001) with an average difference of .03 mm (standard deviation, 2.99 mm) was found between MRI and procedural measurements. Neither injection level nor BMI had a significant influence on the difference in depth. Conclusion: When combined with traditional safety techniques, obtaining preprocedural MRI depth measurements can provide a reliable method in predicting the true needle depth to safely enter the epidural space. Because the majority of patients undergoing interlaminar cervical epidural steroid injections will have already obtained MRI, measuring the distance preprocedurally is a simple and practical method for physicians to implement. Key words: Cervical, fluoroscopy, radiculopathy, injection, contra-lateral oblique, contrast, safety, complications, spinal stenosis, radiation, interlaminar

Degenerative tears of the posterior horn of the medial meniscus: correlation between MRI findings and outcome following intra-articular steroid/bupivacaine injection of the knee

To evaluate the response of symptomatic degenerative tears of the posterior horn of the medial meniscus to guided intra-articular knee steroid/bupivacaine injection and to correlate clinical outcomes with preprocedural findings at magnetic resonance imaging (MRI). Sixty patients who had clinical and MRI evidence of a symptomatic degenerative tear of the posterior horn of the medial meniscus, isolated or accompanied by additional features of degenerative arthritis, who had failed conservative approaches (physiotherapy, non-steroidal anti-inflammatories, and 3 months rest/knee bracing) were included in the study. Patients underwent intra-articular knee steroid/bupivacaine injection and were followed clinically for a minimum of 6 months. Preprocedural MRI findings were correlated with duration of symptoms, clinical response to injection (recorded as complete, partial or no response) and duration of response to injection. Forty-nine of 60 patients (82%) reported an improvement in symptoms following guided intra-articular knee steroid/bupivacaine injection (complete: 25 patients (42%), partial: 24 (40%) patients). Improvement was sustained in 32 of 60 patients (53%) at follow-up. Thirteen of 18 patients (72%) who had an isolated degenerative tear of the posterior horn of the medial meniscus recorded a complete resolution of symptoms. This was sustained at follow-up in 10 patients (56%). Intra-articular steroid/bupivacaine knee joint injection reduced pain symptoms in the majority of patients (81.7%) with degenerative tears of the posterior horn of the medial meniscus, usually with a sustained response. Preprocedural MRI appearances correlate with response to injection. Patients with isolated tears are more likely to have a favourable outcome.

Comparative Evaluation of Angioscopy and Intravascular Ultrasound for Assessing Plaque Protrusion During Carotid Artery Stenting Procedures

Evaluation of plaque protrusion after carotid artery stenting (CAS) is important for predicting periprocedural ischemic complications. In contrast to intravascular ultrasound (IVUS), angioscopy allows direct visualization of the plaque. The aim of this study was to evaluate utility and safety of angioscopy during CAS and compare it with IVUS. The study included 13 carotid artery stenosis lesions in 11 consecutive patients (mean age 70.5 years; 10 men) at a single center. During CAS procedure, poststenting plaque protrusion was evaluated with angioscopy and IVUS. Mean level of internal carotid artery stenosis was 79.2%. Eight lesions were symptomatic, and 5 lesions were predicted to have vulnerable plaque by preprocedural magnetic resonance imaging. A carotid WALLSTENT was placed in all cases. After stenting, angioscopy provided good visualization in all cases. Plaque protrusions were observed in 1 case by IVUS and in 8 cases by angioscopy. Diffusion-weighted imaging showed positive lesions in 3 cases (23%). For 2 of these lesions, plaque protrusions were observed by angioscopy but not by IVUS. All lesions associated with positive diffusion-weighted imaging findings were observed to have yellow plaque on angioscopy. Angioscopy provided direct visualization of stent lumens after CAS. Angioscopy detected more plaque protrusion than IVUS and allowed clearer observation of plaque characteristics. Angioscopy may be more useful than IVUS for examination of plaque protrusion and plaque evaluation after CAS, especially for plaque identified as potentially vulnerable by preprocedural examination.

Radiofrequency Ablation of the Marginal Venous System in Patients with Venous Malformations.

To evaluate radiofrequency ablation (RFA) for closure of marginal veins in pediatric and adult patients with venous malformations. Medical records, imaging and procedure details were retrospectively reviewed in patients who underwent RFA of the marginal vein in a 17-month period. Additional sclerotherapy (n = 19) and coil embolization of the marginal vein were performed (n = 2). A total of 23 marginal veins were treated in 20 patients. Mean age at treatment was 16years ± 9.4 (1-37years). Pre-procedural magnetic resonance imaging revealed thoracoabdominal marginal veins in 3 patients. A type I marginal vein (draining in the great saphenous vein below the popliteal vein) was identified in 1 and type IIa/IIb (draining in a median/lateral accessory saphenous vein) in 2/8 cases. Type III (draining into the profunda femoral vein) was detected in 8, and type IV (draining into gluteal veins) in 1. Mean diameter of the marginal veins was 13.2mm ± 4 (7-20mm). Patency was found in 1 during follow-up (22months ± 9.8). Complete or partial occlusion was achieved in 94.5% of the veins. One patient showed signs of thrombophlebitis after the procedure, and another incomplete paresis of the peroneal nerve. RFA is effective as minimally invasive treatment of the marginal venous system. These veins should be treated early in life. Marginal veins with large diameter, residual tributaries and the intrafascial courses usually require adjunct coil embolization and sclerotherapy. Case series, Level IV.

Safety and Feasibility of Melody Transcatheter Pulmonary Valve Replacement in the Native Right Ventricular Outflow Tract: A Multicenter Pediatric Heart Network Scholar Study

ObjectivesThis study sought to determine the safety and feasibility of transcatheter pulmonary valve replacement (TPVR) using the Melody valve in native (nonconduit) right ventricular outflow tracts (nRVOT), and to identify factors associated with successful TPVR. BackgroundThe Melody valve is Food and Drug Administration–approved for TPVR within right ventricle-to-pulmonary artery conduits and bioprosthetic pulmonary valves. However, most patients needing pulmonary valve replacement have nRVOT and TPVR has been adapted for this indication. MethodsIn this multicenter retrospective study of all patients presenting for nRVOT TPVR, we collected pre-procedural magnetic resonance imaging, echocardiography, and catheterization data, and evaluated procedural and early outcomes. ResultsOf 229 patients (age 21 ± 15 years from 11 centers), 132 (58%) had successful TPVR. In the remaining 97, TPVR was not performed, most often because of prohibitively large nRVOT (n = 67) or compression of the aortic root or coronary arteries (n = 18). There were no deaths and 5 (4%) serious complications, including pre-stent embolization requiring surgery in 4 patients, and arrhythmia in 1. Higher pre-catheterization echocardiographic RVOT gradient was associated with TPVR success (p = 0.001) and larger center volume approached significance (p = 0.08). Magnetic resonance imaging anterior-posterior and lateral RVOT diameters were smaller in implanted versus nonimplanted patients (18.0 ± 3.6 mm vs. 20.1 ± 3.5 mm; p = 0.005; 18.4 ± 4.3 mm vs. 21.5 ± 3.8 mm; p = 0.002). ConclusionsTPVR in the nRVOT was feasible and safe. However, nearly half the patients presenting for catheterization did not undergo TPV implantation, mainly because of prohibitively large nRVOT size. Improved understanding of magnetic resonance imaging data and availability of larger devices may improve the success rate for nRVOT TPVR.

Vertebroplasty in Elderly Patients: A Clinical Effectiveness Analysis

Minimally invasive vertebral augmentation procedures (VAP) have been first introduced to provide pain relief in patients with osteoporotic vertebral fractures (VF). However, in the last decade scientific literature revealed to be quite controversial about their efficacy. The aim of this review was to analyze clinical evidences from current literature, supported by our own experience. Compared to conservative therapies, VAP represent an effective treatment for recent VF and, in elderly patients, reduce mortality and morbidity. Advances in technology have widened the fields of application towards other spine pathologies typical of elderly, such as primary and metastatic tumors. In patients with severe pain for recent or un-healed vertebral fracture, VAP are clinically more effective than conservative treatment. Accurate pain assessment and pre-procedural Magnetic Resonance Imaging are highly recommended to obtain optimal patient selection and best treatment results.

Magnetic resonance imaging guidance for the optimization of ventricular tachycardia ablation.

Catheter ablation has an important role in the management of patients with ventricular tachycardia (VT) but is limited by modest long-term success rates. Magnetic resonance imaging (MRI) can provide valuable anatomic and functional information as well as potentially improve identification of target sites for ablation. A major limitation of current MRI protocols is the spatial resolution required to identify the areas of tissue responsible for VT but recent developments have led to new strategies which may improve substrate assessment. Potential ways in which detailed information gained from MRI may be utilized during electrophysiology procedures include image integration or performing a procedure under real-time MRI guidance. Image integration allows pre-procedural magnetic resonance (MR) images to be registered with electroanatomical maps to help guide VT ablation and has shown promise in preliminary studies. However, multiple errors can arise during this process due to the registration technique used, changes in ventricular geometry between the time of MRI and the ablation procedure, respiratory and cardiac motion. As isthmus sites may only be a few millimetres wide, reducing these errors may be critical to improve outcomes in VT ablation. Real-time MR-guided intervention has emerged as an alternative solution to address the limitations of pre-acquired imaging to guide ablation. There is now a growing body of literature describing the feasibility, techniques, and potential applications of real-time MR-guided electrophysiology. We review whether real-time MR-guided intervention could be applied in the setting of VT ablation and the potential challenges that need to be overcome.

The Termination Level of the Dural Sac Relevant to Caudal Epidural Block in Lumbosacral Transitional Vertebrae: A Comparison between Sacralization and Lumbarization Groups

Lumbosacral transitional vertebrae (LSTV) are a relatively common variant and have been considered as one of the reasons for back pain. It is not unusual for clinicians to encounter patients with LSTV who require caudal epidural block (CEB) for pain management. We investigated the termination level of the dural sac (DS) and anatomical features of the lumbosacral region relevant to CEB in patients with LSTV and compared these findings between sacralization and lumbarization groups. A retrospective evaluation. A university hospital with inpatient and outpatient LSTV cases presenting low back pain. Four hundred ninety-four LSTV patients were included and categorized into sacralization (n = 201) or lumbarization groups (n = 293). Magnetic resonance imaging (MRI) of all of the LSTV patients were reviewed to determine the level of DS termination, the shortest distance between the apex of the sacral hiatus and DS, and the presence and the caudal level of sacral perineural cysts. Each lumbosacral vertebra column was divided into 3 equal portions (upper, middle, and lower thirds). The MRI findings in both of the groups were compared and analyzed. The distribution frequency of the levels of DS termination demonstrated a significant difference between the 2 groups. The mean caudal DS level in the lumbarization group was significantly lower than the sacralization group (lower third of the S2 [131 {44.7%} of 293 patients] vs. lower third of the S1 [78 {38.8%} of 201 patients]). The DS terminated at the S3 in more than 19% of the lumbarization group, whereas in only one case of the sacralization group. Although the incidence of perineural cysts was not significantly different between the 2 groups, the mean level of caudal margin of perineural cysts in the lumbarization group was significantly lower than the sacralization group (middle third of the S3 [10 {35.7%} of 28 cases] vs. middle third of the S2 [11 {44%} of 25 cases]). This study reveals several limitations including the practical challenge of accurate enumeration of the transitional segment and the constraints on generalizability posed by the single-country study. When planning CEB for patients with LSTV, pre-procedural MRI to check the anatomical structures, including the level of DS termination and caudal margin of perineural cysts, would be of great use for lowering the risk of unexpected dural puncture during the procedure, especially in the lumbarization cases. Termination of the dural sac, dural sac termination, lumbosacral transitional vertebrae, transitional vertebra, caudal epidural block.

Magnetic resonance imaging characteristics of lesions relate to the difficulty of peripheral arterial endovascular procedures

ObjectiveLimitations with current peripheral arterial imaging modalities make selection of patients for percutaneous vascular interventions difficult. The purpose of this study was to determine whether a novel preprocedural magnetic resonance imaging (MRI) method can identify lesions that would be more challenging to cross during percutaneous vascular intervention. MethodsFourteen patients with peripheral arterial disease underwent MRI before their intervention. A novel steady-state free precession flow-independent magnetic resonance (MR) angiogram was used to locate lesions, and an ultrashort echo time image was used to characterize hard lesion components including calcium and dense collagen. Lesions were characterized as hard if ≥50% of the lumen was occluded with calcium or collagen (as determined by MR image characteristics) in the hardest cross section within the lesion. The primary outcome was the time it took to cross a guidewire through the target lesion. The secondary outcome was the need for stenting. ResultsOf 14 lesions, 8 (57%) were defined as hard and 6 (43%) were soft on the basis of MR image characteristics. Hard lesions took significantly longer to cross than soft lesions (average, 14 minutes 49 seconds vs 2 minutes 17 seconds; P = .003). Hard lesions also required stenting more often than soft lesions (Fisher exact test, P = .008). Of 14 lesions, 2 (14%) could not be crossed with a guidewire, and both lesions were hard. MR images also detected occult patencies and noncalcified hard lesions that could not be seen on X-ray angiography. ConclusionsMRI can be used to determine which peripheral arterial lesions are more difficult to cross with a guidewire. Future work will determine whether MRI lesion characterization can predict long-term endovascular outcomes to aid in procedure planning.

Massive bleeding after EUS-guided walled-off necrosis drainage.

A 58-year-old man with a history of necrotizing pancreatitis of biliary causes 8 weeks previously presented with a 20-pound weight loss and daily epigastric pain. Abdominal magnetic resonance imaging (MRI) demonstrated a 12.3-cm collection surrounding the pancreatic body with a large amount of debris, consistent with walled-off necrosis (WON) (Fig. 1A). Given the collection size and the patient’s symptoms, we proceeded with EUS-guided drainage using a lumen-apposing metal stent (LAMS).Figure 1A, Preprocedural abdominal MRI demonstrating a large (12.3 × 7.4 × 6.4 cm) complex fluid collection with a thick outer wall surrounding the pancreatic body (arrow) and suspected disruption of the pancreatic duct (arrowheads). B, EUS view demonstrating the LAMS catheter (arrowhead) inside the collection, and the distal end of the deployed stent (arrow). C, Upper endoscopic view showing dilation of the cystgastrostomy by use of a wire-guided dilating balloon. D, Upper endoscopic view showing bleeding at the proximal end of the LAMS (gastric side). E, Arteriographic view showing the deployed LAMS (arrow) and no evidence of extravasation of contrast material. F, Duodenoscopic view revealing the previously placed cystgastrostomy stent on the gastric body. A hemostatic clip is seen at the site of active bleeding underneath the stent. G, EGD view demonstrating the gastric side of the cystgastrostomy without bleeding. H, MRI revealing nearly resolved walled-off necrosis (arrow). I, EGD views before (left) and after (right) LAMS removal. MRI, magnetic resonance imaging; LAMS, lumen-apposing metal stent. The arrow represents the place where the stent was.View Large Image Figure ViewerDownload Hi-res image Download (PPT) Once an appropriate position was identified, the posterior wall of the gastric body and the WON were punctured under sonographic guidance by use of an electrocautery-enhanced LAMS (Hot-Axios Stent, 15 × 10 mm, Boston-Scientific, Natick, Mass). Pure cut current with 100 W was used to advance the LAMS in a single step with subsequent deployment (Fig. 1B). The stent was dilated to 15 mm by use of a wire-guided dilating balloon (Fig. 1C). Immediate bleeding was seen at the gastric side of the LAMS, which subsided spontaneously (Fig. 1D). The patient was hospitalized for overnight observation. Three hours later, he experienced hematochezia with hemodynamic instability (hemoglobin dropped from 13.1 to 7.3 g/dL). He was transferred to the intensive care unit, where fluid resuscitation was provided. A CT angiogram and an arteriogram did not demonstrate any evidence of bleeding (Fig. 1E). No therapy was performed. Intermittent hematochezia persisted over the next 2 days. EGD revealed intermittent active bleeding along the underside of the LAMS along the gastric lumen. Attempts to place a hemoclip were challenging with a forward-viewing gastroscope. This was exchanged for a duodenoscope (Olympus America, Center Valley, Pa), and a hemostatic clip (Boston Scientific Corporation, Marlborough, Mass) was successfully placed at the site of active bleeding (Fig. 1F). Repeated EGD the following day demonstrated no further bleeding (Fig. 1G). He was discharged on hospital day 7. At his 1-month follow-up visit, MRI showed resolution of the WON (Fig. 1H). EGD was performed to remove the LAMS without difficulty (Fig. 1I). EUS-guided drainage of WON has become more feasible with the advent of LAMSs. However, severe adverse events, such as stent-related bleeding, can occur. All possible adverse events should be carefully discussed with patients. In this video, we highlight how severe hemorrhage related to LAMS placement was diagnosed and subsequently treated by use of a duodenoscope for hemoclip deployment (Video 1, available online at www.VideoGIE.org). After the procedure, it is advisable to observe these patients in the hospital. All authors disclosed no financial relationships relevant to this publication. eyJraWQiOiI4ZjUxYWNhY2IzYjhiNjNlNzFlYmIzYWFmYTU5NmZmYyIsImFsZyI6IlJTMjU2In0.eyJzdWIiOiIzMTRiNGFmZDU4YTNmNmFmMWY3ODc1NDU1Y2UzZjBjYiIsImtpZCI6IjhmNTFhY2FjYjNiOGI2M2U3MWViYjNhYWZhNTk2ZmZjIiwiZXhwIjoxNjc4NTk1Njc5fQ.LTtv5_hiFqcFDuDH4KSQ-MBgPcW667MsnOtSacD7p-rtrXv9x7Ri8v0ng4X1TuLwRNPhTF28l_QzrirPt49WkSrMu8sMO39fFNwvxFg0BLs_E5aTKlc5TrPpd3fuNf0F7M4vAY5ngG-FbPAhHU0xhYf9F6_PfzyMXxWDD6CCSjJph2MPZ0DW7aBSjqO22pHbzJorobPPIOiAiDIhzH4QxK_oTpxklvuRhGf9HhtN5YP6CqLXnk1_f3k4arc--DIxprUgYLNwscG-gKZKi1LEheXkCeeVfHHeL-_LUlSJMUI3yC7XImAACE4irMHj_G3t1ixgkz5tCQD3Fx2d0fttWg Download .mp4 (51.51 MB) Help with .mp4 files Video 1EUS-guided drainage of walled-off pancreatic necrosis by use of a lumen-apposing metal stent, complicated by cystgastrostomy bleeding. Duodenoscope-guided clip placement was used to successfully achieve control of bleeding. Download .docx (.01 MB) Help with docx files Video Script

Does intra-tumoural fat on MRI predict visibility of small (≤3 cm) hepatocellular carcinomas during ultrasound-guided tumour ablation?

To assess if intra-tumoural fat on magnetic resonance imaging (MRI) affects the ultrasonographic(US) visibility of small (≤3 cm) hepatocellular carcinomas (HCC) during radiofrequency ablation (RFA). Institutional review board approval was obtained. A retrospective review of all patients who underwent image-guided ablation between 1 January 2010 and 31 April 2015 was performed. Patients with HCC who underwent US RFA were included. Inclusion criteria included small tumours (≤3 cm), treatment-naive cases or new focus of HCC in a different and untreated segment, and pre-procedural MRI. The presence of intra-tumoural fat was determined retrospectively via in-and-out-of-phase MRI. Other factors that potentially affect ultrasonographic visibility, such as background fatty liver, presence of cirrhosis, tumour size, and distance from diaphragm, were recorded. Ninety procedures performed on 74 patients (62 men and 12 women; mean age: 67.3 years; range: 39-88 years). Seventy-two tumours were visible on US (hypoechoic n=35, hyperechoic n=28, heterogeneous n=9). Intra-tumoural fat was seen in 23 tumours (25.6%, hyperechoic n=17, hypoechoic n=6). The presence of intra-tumoural fat (p=0.005) and distance from diaphragm (p=0.007) were found to be statistically significant factors affecting tumour visibility on planning US. The presence of background fatty liver (p=0.485), cirrhosis (p=0.48), and tumour size (p=0.15) were not found to be significant. The present study shows that the presence of intra-tumoural fat in small HCCs on pre-procedural MRI can accurately predict their visibility on planning US during percutaneous tumour ablation.

Cervical Epidural Depth: Correlation Between Cervical MRI Measurements of the Skin-to-Cervical Epidural Space and the Actual Needle Depth During Interlaminar Cervical Epidural Injections.

The purpose of this study was to assess the correlation between skin-to-epidural space depth, as measured on cervical magnetic resonance imaging (MRI), and actual needle depth, as measured by Tuohy needle markings during cervical epidural steroid injections. We conducted a retrospective review of cervical MRI images to determine estimated depth from skin to epidural space. Of the 121 reviewed patients who underwent cervical epidural steroid injections, 81 met inclusion criteria and were retained for data analysis. At the C6-C7 level, the estimated needle depth according to MRI images was 6.03 ± 1.15 cm (mean ± SD) and the actual needle depth was 5.62 ± 0.77 cm. At the C7-T1 level, the estimated needle depth based on MRI images was 5.90 ± 1.05 cm and the actual needle depth was 5.73 ± 0.98 cm. At both C6-C7 and C7-T1, MRI depth (P < 0.009, P < 0.001) and body mass index (P < 0.001, P < 0.002) were significantly associated with actual depth. Estimates of needle depth made with MRI were consistently slightly deeper than the actual loss-of-resistance needle depth, indicating that the provider should employ caution when using MRI predictive depths. Information garnered from preprocedure MRIs can be used to improve the safety of cervical epidural steroid injection procedures.

Learning Non-rigid Deformations for Robust, Constrained Point-based Registration in Image-Guided MR-TRUS Prostate Intervention.

Accurate and robust non-rigid registration of pre-procedure magnetic resonance (MR) imaging to intra-procedure trans-rectal ultrasound (TRUS) is critical for image-guided biopsies of prostate cancer. Prostate cancer is one of the most prevalent forms of cancer and the second leading cause of cancer-related death in men in the United States. TRUS-guided biopsy is the current clinical standard for prostate cancer diagnosis and assessment. State-of-the-art, clinical MR-TRUS image fusion relies upon semi-automated segmentations of the prostate in both the MR and the TRUS images to perform non-rigid surface-based registration of the gland. Segmentation of the prostate in TRUS imaging is itself a challenging task and prone to high variability. These segmentation errors can lead to poor registration and subsequently poor localization of biopsy targets, which may result in false-negative cancer detection. In this paper, we present a non-rigid surface registration approach to MR-TRUS fusion based on a statistical deformation model (SDM) of intra-procedural deformations derived from clinical training data. Synthetic validation experiments quantifying registration volume of interest overlaps of the PI-RADS parcellation standard and tests using clinical landmark data demonstrate that our use of an SDM for registration, with median target registration error of 2.98 mm, is significantly more accurate than the current clinical method. Furthermore, we show that the low-dimensional SDM registration results are robust to segmentation errors that are not uncommon in clinical TRUS data.

Preprocedural MRI and MRA in planning fibroid embolization.

This pictorial review aims to discuss and illustrate the up-to-date use of preprocedural magnetic resonance imaging (MRI) in selecting patients and planning uterine artery embolization (UAE). The merits of magnetic resonance angiography (MRA) in demonstrating the pelvic vasculature to guide UAE are highlighted. MRI features of fibroids and their main differential diagnoses are presented. Fibroid characteristics, such as location, size, and enhancement, which may impact patient selection and outcome, are presented based on recent literature. Pelvic arterial anatomy relevant to UAE, including vascular variants are illustrated, with conventional angiography and MRA imaging correlation. MRA preprocedural determination of the optimal projection angles for uterine artery catheterization is straightforward and constitutes an important strategy to minimize ionizing radiation exposure during UAE. A reporting template for MRI/MRA preassessement of UAE for fibroid treatment is provided.

Ventricular arrhythmias associated with left ventricular noncompaction: Electrophysiologic characteristics, mapping, and ablation

Left ventricular noncompaction (LVNC) is a primary cardiomyopathy that can present with recurrent ventricular arrhythmias (VAs). Data on the benefit of catheter ablation of VAs in LVNC are lacking. The purpose of this study was to describe the electrophysiologic features and outcomes of catheter ablation of VAs in LVNC. The cohort consisted of 9 patients (age 42 ± 15 years) with diagnosis of LVNC based on established criteria and VA (ventricular tachycardia [VT] in 3 and frequent premature ventricular contractions (PVCs) in 6) despite treatment with a mean of 2 ± 1 antiarrhythmic drugs. Ablation sites were identified using a combination of entrainment, activation, late/fractionated potential ablation, and pace-mapping. A total of 8 patients (89%) had left ventricular (LV) systolic dysfunction (mean ejection fraction 40% ± 13%). Patients who presented with VT had evidence of abnormal electroanatomic substrate involving the mid- to apical segments of the LV, which matched the noncompacted myocardial segments identified by preprocedural magnetic resonance imaging or echocardiography. In patients presenting with frequent PVCs, the site of origin was identified at the papillary muscles (50%) and/or basal septal regions (67%). After median follow-up of 4 years (range 1-11) and a mean of 1.8 ± 1.1 procedures, VAs recurred in 1 patient (11%). Significant improvement in LV function occurred in 4 of 8 cases (50%). No patients died or underwent heart transplantation. The VA substrate in patients with LVNC and VT typically involves the mid-apical LV segments, whereas focal PVCs often arise from LV basal-septal regions and/or papillary muscles. Catheter ablation is safe and effective in achieving good VA control over long-term follow-up in most patients.

MR and CT Imaging to Optimize CT-Guided Biopsies in Suspected Spondylodiscitis

The diagnostic value of computed tomography (CT)-guided spinal biopsy in patients with suspected spondylodiscitis is reported inconsistently in the literature. Our aim was to evaluate associations between procedural, clinical, and imaging parameters and the diagnostic yield of CT-guided spinal biopsy. One hundred and two procedures performed in 87 patients with clinically suggested spondylodiscitis were analyzed retrospectively. Preprocedural magnetic resonance (MR) and CT images were evaluated regarding signal alterations, vertebral destruction, and soft-tissue involvement. The position of the biopsy needle in correlation with MR imaging findings was assessed. Patient characteristics and clinical details were noted. Parameters were compared in patients with positive and negative microbiological and histologic results. Following microbiologic and histologic analysis, infectious spondylodiscitis was diagnosed in 29 and 23 biopsies, respectively. Microbiology results were significantly higher in biopsy specimens with central needle positioning within contrast enhancing tissue in correlation with the MR images (36% vs. 7%; P= 0.005). Biopsy specimens positioned in fluid-equivalent hyperintense discs in T2-weighted sequences yielded significantly lower microbiology results (6% vs. 33%; P= 0.036). Purely lytic endplate destruction and mixed vertebral density as shown by CT increased microbiology results (60% vs. 24%; P= 0.028). Previous antibiotic treatment for any cause did not influence microbiology yields significantly (P= 0.232). MR imaging is mandatory to determine the optimal biopsy position. No clinical or imaging parameter could rule out a positive biopsy result and thus omit an unnecessary procedure. Biopsy should not be avoided if antibiotic treatment has previously been administered.

Targeted multimodal nano-reporters for pre-procedural MRI and intra-operative image-guidance.

Multimodal-imaging probes offer a novel approach, which can provide detail diagnostic information for the planning of image-guided therapies in clinical practice. Here we report targeted multimodal Nd3+-doped upconversion nanoparticle (UCNP) imaging reporters, integrating both magnetic resonance imaging (MRI) and real-time upconversion luminescence imaging (UCL) capabilities within a single platform. Nd3+-doped UCNPs were synthesized as a core-shell structure showing a bright visible emission upon excitation at the near infrared (minimizing biological overheating and increasing tissue penetration depth) as well as providing strong MRI T2 contrast (high r2/r1 ratio). Transcatheter intra-arterial infusion of Nd3+-doped UCNPs conjugated with anti-CD44-monoclonal antibody allowed for high performance invivo multimodal UCL and MR imaging of hepatocellular carcinoma (HCC) in an orthotopic rat model. The resulted invivo multimodal imaging of Nd3+ doped core-shell UCNPs combined with transcatheter intra-arterial targeting approaches successfully discriminated liver tumors from normal hepatic tissues in rats for surgical resection applications. The demonstrated multimodal UCL and MRI imaging capabilities of our multimodal UCNPs reporters suggest strong potential for invivo visualization of tumors and precise surgical guidance to fill the gap between pre-procedural imaging and intraoperative reality.