Two episodes of cardiac tamponade in the same patient from removing pacing wires and a pericardial drain: A case report

A patient presented for an elective transcatheter aortic valve replacement with temporary transvenous pacing (TVP) wires placement per protocol. On postoperative day 1, the patient remained stable, so the wires were subsequently removed, after which the patient acutely decompensated, with transthoracic echocardiography revealing pericardial effusion. Emergent pericardiocentesis was performed, and a pericardial drain was placed. Three days later, the drain was removed; again, the patient acutely decompensated, requiring another emergent pericardiocentesis. Despite the relatively benign nature of TVP wires and pericardial drains, the possibility of cardiac tamponade should be kept in mind as a potential complication when they are being removed

Vessel Patency Post Irreversible Electroporation

The purpose of the study was to evaluate the effect of Irreversible Electroporation (IRE) on vessel patency in close proximity to the ablation zone.Between January 2010 and November 2013, 101 patients underwent percutaneous IRE procedures using the NanoKnife for primary and metastatic tumors in different organs. Age ranged from 24 to 83 years. A total of 129 lesions were treated. [liver (100), pancreas (18), kidney (3), pelvis (1), aorto-caval lymph nodes (2), adrenal (2), lung (1), retroperitoneal (1), surgical bed of a prior Whipple procedure (1)]. Post treatment contrast-enhanced CT and MRI scans were reviewed to evaluate caliber, patency, and flow defects of vessels in close proximity to the ablation zone (defined as vessels within 0–1 cm from the treatment zone).A total of 158 vessels were examined for patency on follow-up. The mean distance of the vessel from the treatment zone was 2.3 ± 2.5 mm. Ten vessels within the treatment zone were encased by tumor. Mean tumor size was 2.7 + 1.5 cm. Overall mean follow-up was 10.3 months. Abnormal vascular changes were noted in 7 of 158 (4.4 %) vessels. No significant association was found between distances from the treatment zone and presence of narrowing/thrombosis at the follow-up imaging. (Mann–Whitney U, p = 0.772; logistic regression: p = 0.593; odds ratio: 0.908; CI 0.637–1.294).This study demonstrates safety of IRE for the treatment of tumors near the large blood vessels and tumors already encasing the vessels. Further studies to substantiate these findings are essential to validate this crucial advantage of IRE

AN ACCURATE 3D LIVER SEGMENTATION METHOD FOR SELECTIVE INTERNAL RADIATION THERAPY USING A MODIFIED K-MEANS ALGORITHM AND PARALLEL COMPUTING

3-D liver segmentation is vital in computer-assisted surgery applications such as minimal invasive surgery, targeted drug delivery,tumor resection, and donor transplantation. This study describes development and evaluation of a novel liver segmentation paradigm in support of Selective Internal Radiation Therapy (SIRT). Since segmentation accuracy and computational simplicity are the two key features for evaluation, the proposed method couples a modified k-means based segmentation and localized-contouring algorithm to obtain segmentation with high accuracy, based on an optimal number of slices. Furthermore, parallel computing is used to reduce the high computational load required of the process. Minimal manual interaction was required in the form of initialization with no correction or adjustment done during or after the process completion. Five rounds of experiments were performed to determine the accuracy and computational performance of the segmentation algorithm. Results were assessed by comparing volumes obtained from the segmentation algorithm to those obtained by manual segmentation done by experts. Statistical analysis is also carried out to determine if the same accuracy is obtained during multiple runs of the dataset and to determine if the manual initialization has any impact on the accuracy of the results. An average accuracy of 98.27% was achieved in estimating the liver volumes with consistent results obtained in various runs and independently of the user initializing the task. A reduction of 78% in computational time was accomplished by the parallel computing techniques in support of the lengthy segmentation process. Since SIRT requires accurate calculation of the liver volume, this new method provides highly accurate and computationally efficient process required of such challenging clinical requirements

Is Antibiotic Prophylaxis for Percutaneous Radiofrequency Ablation (RFA) of Primary Liver Tumors Necessary? Results From a Single-Center Experience

The purpose of this study was to evaluate need for antibiotic prophylaxis for radiofrequency ablation (RFA) of liver tumors in patients with no significant co-existing risk factors for infection. From January 2004 to September 2013, 83 patients underwent 123 percutaneous RFA procedures for total of 152 hepatocellular carcinoma (HCC) lesions. None of the patients had pre-existing biliary enteric anastomosis (BEA) or any biliary tract abnormality predisposing to ascending biliary infection or uncontrolled diabetes mellitus. No pre- or post-procedure antibiotic prophylaxis was provided for 121 procedures. Data for potential risk factors were reviewed retrospectively and analyzed for the frequency of infectious complications, including abscess formation. One patient (1/121 (0.8%) RFA sessions) developed a large segment 5 liver abscess/infected biloma communicating with the gallbladder 7 weeks after the procedure, successfully treated over 10 weeks with IV and PO antibiotic therapy and percutaneous catheter drainage. This patient did not receive any antibiotics prior to RFA. During the procedure, there was inadvertent placement of RFA probe tines into the gallbladder. No other infectious complications were documented. These data suggest that the routine use of prophylactic antibiotics for liver RFA is not necessary in majority of the patients undergoing liver ablation for HCC and could be limited to patients with high-risk factors such as the presence of BEA or other biliary abnormalities, uncontrolled diabetes mellitus, and large centrally located tumors in close proximity to central bile ducts. Larger randomized studies are needed to confirm this hypothesis

A 3-D liver segmentation method with parallel computing for selective internal radiation therapy

This study describes a new 3-D liver segmentation method in support of the selective internal radiation treatment as a treatment for liver tumors. This 3-D segmentation is based on coupling a modified k-means segmentation method with a special localized contouring algorithm. In the segmentation process, five separate regions are identified on the computerized tomography image frames. The merit of the proposed method lays in its potential to provide fast and accurate liver segmentation and 3-D rendering as well as in delineating tumor region(s), all with minimal user interaction. Leveraging of multicore platforms is shown to speed up the processing of medical images considerably, making this method more suitable in clinical settings. Experiments were performed to assess the effect of parallelization using up to 442 slices. Empirical results, using a single workstation, show a reduction in processing time from 4.5 h to almost 1 h for a 78% gain. Most important is the accuracy achieved in estimating the volumes of the liver and tumor region(s), yielding an average error of less than 2% in volume estimation over volumes generated on the basis of the current manually guided segmentation processes. Results were assessed using the analysis of variance statistical analysis