Degenerate mode band-pass birdcage coil for accelerated parallel excitation.

An eight-rung, 3T degenerate birdcage coil (DBC) was constructed and evaluated for accelerated parallel excitation of the head with eight independent excitation channels. Two mode configurations were tested. In the first, each of the eight loops formed by the birdcage was individually excited, producing an excitation pattern similar to a loop coil array. In the second configuration a Butler matrix transformed this "loop coil" basis set into a basis set representing the orthogonal modes of the birdcage coil. In this case the rung currents vary sinusoidally around the coil and only four of the eight modes have significant excitation capability (the other four produce anticircularly polarized (ACP) fields). The lowest useful mode produces the familiar uniform B(1) field pattern, and the higher-order modes produce center magnitude nulls and azimuthal phase variations. The measured magnitude and phase excitation profiles of the individual modes were used to generate one-, four-, six-, and eightfold-accelerated spatially tailored RF excitations with 2D and 3D k-space excitation trajectories. Transmit accelerations of up to six-fold were possible with acceptable levels of spatial artifact. The orthogonal basis set provided by the Butler matrix was found to be advantageous when an orthogonal subset of these modes was used to mitigate B(1) transmit inhomogeneities using parallel excitation.     

Imaging glioma extent with 131I-TM-601.

TM-601, a 36-amino-acid peptide, selectively binds to glioma cells but not normal brain parenchyma. A phase I/II clinical trial of intracavitary 131I-TM-601 in adult patients with recurrent high-grade glioma was performed to determine the biodistribution and toxicity of this potential therapy. We evaluated imaging and biodistribution data from this trial to assess whether 131I-TM-601 might be useful in determining tumor extent. METHODS: Adult patients with recurrent high-grade gliomas underwent tumor resection, implantation of an intracavitary reservoir, and a single-dose injection of 370 MBq (10 mCi) 131I-TM-601 (0.25-1.0 mg of 131I-TM-601) 2-4 wks after surgery. Total-body planar scans and whole-brain SPECT scans were obtained on days 0, 1, 2, 3, and 6-8 after injection. Postresection MR images were coregistered to the SPECT scans using image analysis software. Analysis of the rate of radioactive decay and biologic elimination from the body and at the cavity site was performed. T1-weighted with gadolinium contrast (T1-Wc), T2-weighted (T2), and SPECT volumes were estimated by stereological Cavalieri sections and compared for overlap. RESULTS: Nonbound 131I-TM-601 was eliminated by 48 h after injection with the remaining radiolabeled peptide bound to tumor for at least 6-8 d. Biologic decay rates from 24 to 168 h after injection were only slightly shorter than the physical decay of 131I (6.3 vs. 8.0 d). A comparison of tumor volume estimates using all 3 imaging parameters indicated that 131I-TM-601-determined tumor volumes more closely paralleled T2 volumes than T1-Wc volumes. Overlap between coregistered MRI and SPECT scans corroborated the presence of radiolabeled peptide in the vicinity of infiltrating tumor up to 168 h after injection. CONCLUSION: 131I-TM-601 provides a reliable estimate for primary tumor extent. Further modification of this radiopeptide with other better imaging isotopes may provide an important tool for determining tumor extent and differentiating regions of viable tumor from necrosis.     

Changes in connectivity profiles as a mechanism for strategic control over interfering subliminal information

Human behavior can be influenced by information that is not consciously perceived. Recent behavioral and electrophysiological evidence suggests, however, that the processing of subliminal stimuli is not completely beyond an observer's conscious control. The present study aimed to characterize the cortical network that implements strategic control over interfering subliminal information at multiple stages. Fourteen participants underwent functional magnetic resonance imaging (fMRI) scanning while performing a metacontrast masking paradigm. We systematically varied the amount of conflicting versus non-conflicting trials across experimental blocks, and behavioral performance demonstrated strategic effects whenever a high proportion of subliminal prime stimuli induced response competition. A psychophysiological interaction analysis revealed the pre-supplementary motor area (pre-SMA) to exhibit context-dependent covariation with activation in the lateral occipital complex (LOC) and the putamen. The pre-SMA thereby appears to fulfill a superordinate function in the control of processing subliminal information by simultaneously modulating perceptual analysis and motor selection.     

Ischemic preconditioning for major liver resection under vascular exclusion of the liver preserving the caval flow: a randomized prospective study

BACKGROUND: Two randomized prospective studies suggested that ischemic preconditioning (IP) protects the human liver against ischemia-reperfusion injury after hepatectomy performed under continuous clamping of the portal triad. The primary goal of this study was to determine whether IP protects the human liver against ischemia-reperfusion injury after hepatectomy under continuous vascular exclusion with preservation of the caval flow. STUDY DESIGN: Sixty patients were randomly divided into two groups: with (n=30; preconditioning group) and without (n=30; control group) IP (10 minutes of portal triad clamping and 10 minutes of reperfusion) before major hepatectomy under vascular exclusion of the liver preserving the caval flow. Serum concentrations of aspartate transferase, alanine transferase, glutathione-S-transferase, and bilirubin and prothrombin time were regularly determined until discharge and at 1 month. Morbidity and mortality were determined in both groups. RESULTS: Peak postoperative concentrations of aspartate transferase were similar in the groups with and without IP (851 +/- 1,733 IU/L and 427 +/- 166 IU/L respectively, p=0.2). A similar trend toward a higher peak concentration of alanine transferase and glutathione-S-transferase was indeed observed in the preconditioning group compared with the control group. Morbidity and mortality rates and lengths of ICU and hospitalization stays were similar in both groups. CONCLUSIONS: IP does not improve liver tolerance to ischemia-reperfusion after hepatectomy under vascular exclusion of the liver with preservation of the caval flow. This maneuver does not improve postoperative liver function and does not affect morbidity or mortality rates. The clinical use of IP through 10 minutes of warm ischemia in this technique of hepatectomy is not currently recommended.     

Cholelithiasis: Therapeutisches Splitting als Standard?

At the moment, therapeutic splitting is still regarded by the vast majority of surgeons as the gold standard for stones in the common bile duct. Endoscopic clearance of the duct certainly is much less invasive than open exploration. However, this does not apply when compared with laparoscopic stone removal. Both are equivalent in respect to stone clearance rates, but the laparoscopic techniques protect patients from the long-term sequelae of endoscopic papillotomy. This can be important particularly for younger patients. Laparoscopic bile duct exploration is cost-effective and safe. Special experience in laparoscopic surgical techniques, however, is mandatory. Thus, surgeons should intensify their training in laparoscopic bile duct exploration in order to increase the acceptance of these techniques.     

In-vivo studies on Haemaccel-fibronectin interaction in man

An enzyme-linked immunoassay has been recently set up for direct measurement of the binding capacity of plasma fibronectin to gelatin. This binding capacity could be completely inhibited in vitro by an eight-fold excess of gelatin, of Haemaccel, but not of Geloplasma. On the contrary, the levels of immunoreactive fibronectin measured by laser nephelometry did not change, in presence of 10 to 1000 micrograms ml-1 of gelatin, of Haemaccel or of Geloplasma. When infused into normal volunteers, Haemaccel provoked a strong and immediate inhibition of the plasma fibronectin binding capacity to gelatin. This inhibition was dose-dependent and maximal after infusion of 500 ml of Haemaccel. Twenty-four hours after this infusion, there was a progressive recovery of the gelatin-binding capacity, which was almost completely achieved 96 h later. The formation of complexes between Haemaccel and fibronectin was demonstrated by gel filtration chromatography and by affinity chromatography. Immunoreactive plasma fibronectin levels remained unchanged up to 24 h after infusion of 500 ml of Haemaccel. A transient decline to 50% of its initial value then occurred the second day after the infusion. Therefore, a delay existed between the formation of fibronectin-Haemaccel complexes and their elimination from the bloodstream. This delay decreased when smaller volumes of Haemaccel were infused, which strongly suggests that plasma fibronectin is cleared by means of Haemaccel and does not seem to play a role of opsonin in these conditions.(ABSTRACT TRUNCATED AT 250 WORDS)     

Configuration affects parallel stent grafting results

Objective

A number of adjunctive “off-the-shelf” procedures have been described to treat complex aortic diseases. Our goal was to evaluate parallel stent graft configurations and to determine an optimal formula for these procedures.

Intraoperative Pancreatic Cancer Detection using Tumor-Specific Multimodality Molecular Imaging

Background

Operative management of pancreatic ductal adenocarcinoma (PDAC) is complicated by several key decisions during the procedure. Identification of metastatic disease at the outset and, when none is found, complete (R0) resection of primary tumor are key to optimizing clinical outcomes. The use of tumor-targeted molecular imaging, based on photoacoustic and fluorescence optical imaging, can provide crucial information to the surgeon. The first-in-human use of multimodality molecular imaging for intraoperative detection of pancreatic cancer is reported using cetuximab-IRDye800, a near-infrared fluorescent agent that binds to epidermal growth factor receptor.

Methods

A dose-escalation study was performed to assess safety and feasibility of targeting and identifying PDAC in a tumor-specific manner using cetuximab-IRDye800 in patients undergoing surgical resection for pancreatic cancer. Patients received a loading dose of 100 mg of unlabeled cetuximab before infusion of cetuximab-IRDye800 (50 mg or 100 mg). Multi-instrument fluorescence imaging was performed throughout the surgery in addition to fluorescence and photoacoustic imaging ex vivo.

Results

Seven patients with resectable pancreatic masses suspected to be PDAC were enrolled in this study. Fluorescence imaging successfully identified tumor with a significantly higher mean fluorescence intensity in the tumor (0.09?±?0.06) versus surrounding normal pancreatic tissue (0.02?±?0.01), and pancreatitis (0.04?±?0.01; p?<?0.001), with a sensitivity of 96.1% and specificity of 67.0%. The mean photoacoustic signal in the tumor site was 3.7-fold higher than surrounding tissue.

Conclusions

The safety and feasibilty of intraoperative, tumor-specific detection of PDAC using cetuximab-IRDye800 with multimodal molecular imaging of the primary tumor and metastases was demonstrated.

     

1 Versus 2-cm Excision Margins for pT2-pT4 Primary Cutaneous Melanoma (MelMarT): A Feasibility Study

Background

There is a lack of consensus regarding optimal surgical excision margins for primary cutaneous melanoma?>?1 mm in Breslow thickness (BT). A narrower surgical margin is expected to be associated with lower morbidity, improved quality of life (QoL), and reduced cost. We report the results of a pilot international study (MelMarT) comparing a 1 versus 2-cm surgical margin for patients with primary melanoma?>?1 mm in BT.

Methods

This phase III, multicentre trial [NCT02385214] administered by the Australia & New Zealand Medical Trials Group (ANZMTG 03.12) randomised patients with a primary cutaneous melanoma?>?1 mm in BT to a 1 versus 2-cm wide excision margin to be performed with sentinel lymph node biopsy. Surgical closure technique was at the discretion of the treating surgeon. Patients’ QoL was measured (FACT-M questionnaire) at baseline, 3, 6, and 12 months after randomisation.

Results

Between January 2015 and June 2016, 400 patients were randomised from 17 centres in 5 countries. A total of 377 patients were available for analysis. Primary melanomas were located on the trunk (56.9%), extremities (35.6%), and head and neck (7.4%). More patients in the 2-cm margin group required reconstruction (34.9 vs. 13.6%; p?<?0.0001). There was an increased wound necrosis rate in the 2-cm arm (0.5 vs. 3.6%; p?=?0.036). After 12 months’ follow-up, no differences were noted in QoL between groups.

Discussion

This pilot study demonstrates the feasibility of a large international RCT to provide a definitive answer to the optimal excision margin for patients with intermediate- to high-risk primary cutaneous melanoma.