Off-resonance artifacts correction with convolution in k-space (ORACLE)

Off-resonance artifacts hinder the wider applicability of echo-planar imaging and non-Cartesian MRI methods such as radial and spiral. In this work, a general and rapid method is proposed for off-resonance artifacts correction based on data convolution in k-space. The acquired k-space is divided into multiple segments based on their acquisition times. Off-resonance-induced artifact within each segment is removed by applying a convolution kernel, which is the Fourier transform of an off-resonance correcting spatial phase modulation term. The field map is determined from the inverse Fourier transform of a basis kernel, which is calibrated from data fitting in k-space. The technique was demonstrated in phantom and in vivo studies for radial, spiral and echo-planar imaging datasets. For radial acquisitions, the proposed method allows the self-calibration of the field map from the imaging data, when an alternating view-angle ordering scheme is used. An additional advantage for off-resonance artifacts correction based on data convolution in k-space is the reusability of convolution kernels to images acquired with the same sequence but different contrasts.     

Laparoscopic Staging of Early Ovarian Cancer: Results of a Multi-Institutional Cohort Study

Background  

Minimal access surgery to stage early ovarian cancer (EOC) is still regarded as investigational among many gynecologic oncologists. Reporting outcome data from large cohorts is currently the only practical way to further define the appropriateness of minimally invasive surgery for EOC patients. We sought to investigate the safety, adequacy, and outcome of laparoscopic staging of EOC by using a multi-institutional sample.     

Percutaneous approach in the maintenance and salvage of dysfunctional autologous vascular access for dialysis

Purpose: Endovascular procedures have been increasingly used for salvage of failing vascular access with conflicting results. The aim of this study was to assess the mid-term patency and complication rates of angioplasty procedures performed in a single center for treatment of stenosis compromising vascular accesses. Methods: A prospective database of vascular accesses performed in 2006-2010 was investigated. The endovascular approach was applied following a standardized protocol by a dedicated team. A total of 531 consecutive procedures were reviewed (326 men; mean age 70.94 years). Patency rates were estimated using the Kaplan-Meier method. Results: There were 199 procedures for failing access: 135 were surgical and 64 angioplasties performed for anastomosis (n=27), venous (n=45) or arterial (n=7) stenosis. Immediate technical success of endovascular procedures was 95.3%(61/64); complication rate was 6.3% (4/64). Primary patency rates were 55% at six months, 49% at 12 months, and 21% at 24 months. In the concurrent group of 135 open procedures, primary patency rates were 80% at six months and 67% at 12 months (P=.002); nevertheless, at 24 months, patency was as low as 49%. Cost estimates for angioplasty revealed additional fees ranging from 411.34 to 446.34 Euro with respect to open surgical procedures. Conclusions: Most dysfunctional vascular accesses can be successfully and safely treated by the endovascular route. In spite of poor mid-term durability, the angioplasty balloon might be considered as a bridge, effective, and repeatable solution with reasonable costs to prolong access survival avoiding additional surgery. The failure rate in the mid-term for dysfunctional vascular access may also be high after surgical reintervention.     

Antimicrobial resistance in internal medicine wards

It can be difficult to differentiate acute heart failure syndrome (AHFS) from other causes of acute dyspnea, especially when patients present in extremis. The objective of the study was to determine the predictive value of physical examination findings for pulmonary edema and elevated B-type natriuretic peptide (BNP) levels in patients with suspected AHFS. This was a secondary analysis of a previously reported prospective study of jugular vein ultrasonography in patients with suspected AHFS. Charts were reviewed for physical examination findings, which were then compared to pulmonary edema on chest radiography (CXR) read by radiologists blinded to clinical information and BNP levels measured at presentation. The predictive value of every sign and combination of signs for pulmonary edema on CXR or an elevated BNP was poor. Since physical examination findings alone are not predictive of pulmonary edema or an elevated BNP, clinicians should have a low threshold for using CXR or BNP in clinical evaluation. This brief research report suggests that no physical examination finding or constellation of findings can be used to reliably predict pulmonary edema or an elevated BNP in patients with suspected AHFS.