MRI-based breast volumetry-evaluation of three different software solutions

As lipofilling of the female breast is becoming more popular in plastic surgery, the use of MRI to assess breast volume has been employed to control postoperative results. Therefore, we sought to evaluate the accuracy of magnetic resonance imaging (MRI)-based breast volumetry software tools by comparing the measurements of silicone implant augmented breasts with the actual implant volume specified by the manufacturer. MRI-based volume analysis was performed in eight bilaterally augmented patients (46 ± 9 years) with three different software programs (Brainlab© I plan 2.6 neuronavigation software; mass analysis, version 5.3, Medis©; and OsiriX© v.3.0.2. 32-bit). The implant volumes analysed by the BrainLab© software had a mean deviation of 2.2 ± 1.7% (r?=?0.99) relative to the implanted prosthesis. OsiriX© software analysis resulted in a mean deviation of 2.8 ± 3.0% (r?=?0.99) and the Medis© software had a mean deviation of 3.1 ± 3.0% (r?=?0.99). Overall, the volumes of all analysed breast implants correlated very well with the real implant volumes. Processing time was 10 min per breast with each system and 30 s (OsiriX©) to 5 min (BrainLab© and Medis©) per silicone implant. MRI-based volumetry is a powerful tool to calculate both native breast and silicone implant volume in situ. All software solutions performed well and the measurements were close to the actual implant sizes. The use of MRI breast volumetry may be helpful in: (1) planning reconstructive and aesthetic surgery of asymmetric breasts, (2) calculating implant size in patients with missing documentation of a previously implanted device and (3) assessing post-operative results objectively.

Biocompatibility assessment of the first generation PediaFlow pediatric ventricular assist device

The PediaFlow pediatric ventricular assist device is a miniature magnetically levitated mixed flow pump under development for circulatory support of newborns and infants (3-15 kg) with a targeted flow range of 0.3-1.5 L/min. The first generation design of the PediaFlow (PF1) was manufactured with a weight of approximately 100 g, priming volume less than 2 mL, length of 51 mm, outer diameter of 28 mm, and with 5-mm blood ports. PF1 was evaluated in an in vitro flow loop for 6 h and implanted in ovines for three chronic experiments of 6, 17, and 10 days. In the in vitro test, normalized index of hemolysis was 0.0087 ± 0.0024 g/100L. Hemodynamic performance and blood biocompatibility of PF1 were characterized in vivo by measurements of plasma free hemoglobin, plasma fibrinogen, total plasma protein, and with novel flow cytometric assays to quantify circulating activated ovine platelets. The mean plasma free hemoglobin values for the three chronic studies were 4.6 ± 2.7, 13.3 ± 7.9, and 8.8 ± 3.3 mg/dL, respectively. Platelet activation was low for portions of several studies but consistently rose along with observed animal and pump complications. The PF1 prototype generated promising results in terms of low hemolysis and platelet activation in the absence of complications. Hemodynamic results validated the magnetic bearing design and provided the platform for design iterations to meet the objective of providing circulatory support for young children with exceptional biocompatibility.

Daily organ tracking in intensity-modulated radiotherapy of prostate cancer using an electronic portal imaging device with a dose saving acquisition mode

BACKGROUND AND PURPOSE: Daily use of conventional electronic portal imaging devices (EPID) for organ tracking is limited due to the relatively high dose required for high quality image acquisition. We studied the use of a novel dose saving acquisition mode (RadMode) allowing to take images with one monitor unit per image in prostate cancer patients undergoing intensity-modulated radiotherapy (IMRT) and tracking of implanted fiducial gold markers. PATIENTS AND METHODS: Twenty five patients underwent implantation of three fiducial gold markers prior to the planning CT. Before each treatment of a course of 37 fractions, orthogonal localization images from the antero-posterior and from the lateral direction were acquired. Portal images of both the setup procedure and the five IMRT treatment beams were analyzed. RESULTS: On average, four localization images were needed for a correct patient setup, resulting in four monitor units extra dose per fraction. The mean extra dose delivered to the patient was thereby increased by 1.2%. The procedure was precise enough to reduce the mean displacements prior to treatment to < o =0.3 mm. CONCLUSIONS: The use of a new dose saving acquisition mode enables to perform daily EPID-based prostate tracking with a cumulative extra dose of below 1 Gy. This concept is efficiently used in IMRT-treated patients, where separation of setup beams from treatment beams is mandatory.

Late results after percutaneous closure of patent foramen ovale for secondary prevention of paradoxical embolism using the amplatzer PFO occluder without intraprocedural echocardiography: effect of device size

OBJECTIVES: We sought to assess the safety and clinical efficacy of patent foramen ovale (PFO) closure under fluoroscopic guidance only, without intraprocedural echocardiography. BACKGROUND: Percutaneous PFO closure has been shown to be safe and feasible using several devices. It is generally performed using simultaneously fluoroscopic and transesophageal or intracardiac echocardiographic guidance. Transesophageal echocardiography requires sedation or general anesthesia and intubation to avoid aspiration. Intracardiac echocardiography is costly and has inherent risks. Both lengthen the procedure. The Amplatzer PFO Occluder (AGA Medical Corporation, Golden Valley, Minnesota) can be safely implanted without echocardiographic guidance. METHODS: A total of 620 patients (51 +/- 12 years; 66% male) underwent PFO closure using the Amplatzer PFO Occluder for secondary prevention of presumed paradoxical embolism. Based on size and mobility of the PFO and the interatrial septum, an 18-mm device was used in 50 patients, a 25-mm device in 492, and a 35-mm device in 78. RESULTS: All procedures were successful, with 5 procedural complications (0.8%): 4 arteriovenous fistulae requiring elective surgical correction, and 1 transient ischemic attack. Contrast transesophageal echocardiography at 6 months showed complete closure in 91% of patients, whereas a minimal, moderate, or large residual shunt persisted in 6%, 2%, and 1%, respectively. During a mean follow-up period of 3.0 +/- 1.9 years (median: 2.6 years; total patient-years: 1,871), 5 ischemic strokes, 8 transient ischemic attacks, and no peripheral emboli were reported. Freedom from recurrent ischemic stroke, transient ischemic attack, or peripheral embolism was 99% at 1 year, 99% at 2 years, and 97% at 5 years. CONCLUSIONS: The Amplatzer PFO Occluder affords excellent safety and long-term clinical efficacy of percutaneous PFO closure without intraprocedural echocardiography.

Transapical access closure: the TA PLUG device

OBJECTIVES Percutaneous closure of the transapical (TA) access site for large-calibre devices is an unsolved issue. We report the first experimental data on the TA PLUG device for true-percutaneous closure following large apical access for transcatheter aortic valve implantation. METHODS The TA PLUG, a self-sealing full-core closure device, was implanted in an acute animal study in six pigs (60.2 ± 0.7 kg). All the pigs received 100 IU/kg of heparin. The targeted activated clotting time was left to normalize spontaneously. After accessing the left ventricular apex with a 39 French introducer, the closure plug device was delivered with a 33 French over-the-wire system under fluoroscopic guidance into the apex. Time to full haemostasis as well as rate of bleeding was recorded. Self-anchoring properties were assessed by haemodynamic push stress under adrenalin challenge. An additional feasibility study was conducted in four pigs (58.4 ± 1.1 kg) with full surgical exposure of the apex, and assessed device anchoring by pull-force measurements with 0.5 Newton (N) increments. All the animals were electively sacrified. Post-mortem analysis of the heart was performed and the renal embolic index assessed. RESULTS Of six apical closure devices, five were correctly inserted and fully deployed at the first attempt. One became blocked in the delivery system and was placed successfully at the second attempt. In all the animals, complete haemostasis was immediate and no leak was recorded during the 5-h observation period. Neither leak nor any device dislodgement was observed under haemodynamic push stress with repeated left ventricular peak pressure of up to 220 mmHg. In the feasibility study assessing pull-stressing, device migration occurred at a force of 3.3 ± 0.5 N corresponding to 247.5 mmHg. Post-mortem analyses confirmed full expansion of all devices at the intended target. No macroscopic damage was identified at the surrounding myocardium. The renal embolic index was zero. CONCLUSIONS True-percutaneous left ventricular apex closure following large access is feasible with the self-sealing TA PLUG. The device allows for immediate haemostasis and a reliable anchoring in the acute animal setting. This is the first report of a true-percutaneous closure for large-calibre transcatheter aortic valve implantation access.

A new rechargeable device for deep brain stimulation: a prospective patient satisfaction survey

Background: Deep brain stimulation (DBS) is highly successful in treating Parkinson's disease (PD), dystonia, and essential tremor (ET). Until recently implantable neurostimulators were nonrechargeable, battery-driven devices, with a lifetime of about 3-5 years. This relatively short duration causes problems for patients (e.g. programming and device-use limitations, unpredictable expiration, surgeries to replace depleted batteries). Additionally, these batteries (relatively large with considerable weight) may cause discomfort. To overcome these issues, the first rechargeable DBS device was introduced: smaller, lighter and intended to function for 9 years. Methods: Of 35 patients implanted with the rechargeable device, 21 (including 8 PD, 10 dystonia, 2 ET) were followed before and 3 months after surgery and completed a systematic survey of satisfaction with the rechargeable device. Results: Overall patient satisfaction was high (83.3 ± 18.3). Dystonia patients tended to have lower satisfaction values for fit and comfort of the system than PD patients. Age was significantly negatively correlated with satisfaction regarding process of battery recharging. Conclusions: Dystonia patients (generally high-energy consumption, severe problems at the DBS device end-of-life) are good, reliable candidates for a rechargeable DBS system. In PD, younger patients, without signs of dementia and good technical understanding, might have highest benefit.

Effects of Thoratec pulsatile ventricular assist device (PVAD) timing on the abdominal aortic wave intensity pattern

Arterial waves are seen as possible independent mediators of cardiovascular risks, and the wave intensity analysis (WIA) has therefore been proposed as a method for patient selection for ventricular assist device (VAD) implantation. Interpreting measured wave intensity (WI) is challenging and complexity is increased by the implantation of a VAD. The waves generated by the VAD interact with the waves generated by the native heart, and this interaction varies with changing VAD settings. Eight sheep were implanted with a pulsatile VAD (PVAD) through ventriculo-aortic cannulation. The start of PVAD ejection was synchronized to the native R-wave and delayed between 0 % - 90 % of the cardiac cycle in 10 % steps or phase shifts (PS). Pressure and velocity signals were registered, using a combined Doppler and pressure wire positioned in the abdominal aorta, and used to calculate the WI. Depending on the PS, different wave interference phenomena occurred. Maximum unloading of the left ventricle (LV) coincided with constructive interference and maximum blood flow pulsatility, and maximum loading of the LV coincided with destructive interference and minimum blood flow pulsatility. We believe, that non-invasive WIA could potentially be used clinically to assess the mechanical load of the LV, and to monitor the peripheral hemodynamics such as blood flow pulsatility and risk of intestinal bleeding.

Transcatheter mitral valve implantation (TMVI) using the Edwards FORTIS device.

Transcatheter aortic valve implantation (TAVI) has demonstrated the feasibility of treating valvular heart disease with transcatheter therapy. On the back of this success, various transcatheter concepts are being evaluated to treat other valvular disease, especially mitral regurgitation (MR). The concepts currently approved to treat MR replicate surgical mitral valve repair. However, most of them cannot eliminate MR completely. Similar to TAVI, a transcatheter mitral valve implantation may provide a valuable alternative. The FORTIS transcatheter mitral valve (Edwards Lifesciences, Irvine, CA, USA) is a self-expanding device implanted via a transapical approach. We describe our experience and early results in the first five patients treated on compassionate grounds. We also describe the details of the device, selection criteria and technical details of implantation.

Estimating the benefit of a second bone anchored hearing implant in unilaterally implanted users with a testband.

Conclusion Using a second bone anchored hearing implant (BAHI) mounted on a testband in unilaterally implanted BAHI users to test its potential advantage pre-operatively under-estimates the advantage of two BAHIs placed on two implants. Objectives To investigate how well speech understanding with a second BAHI mounted on a testband approaches the benefit of bilaterally implanted BAHIs. Method Prospective study with 16 BAHI users. Eight were implanted unilaterally (group A) and eight were implanted bilaterally (group B). Aided speech understanding was measured. Speech was presented from the front and noise came either from the left, right, or from the front in two conditions for group A (with one BAHI, and with two BAHIs, where the second device was mounted on a testband) and in three conditions for group B (same two conditions as group A, and in addition with both BAHIs mounted on implants). Results Speech understanding in noise improved with the additional device for noise from the side of the first BAHI (+0.7 to +2.1 dB) and decreased for noise from the other side (-1.8 dB to -3.9 dB). Improvements were highest (+2.1 dB, p = 0.016) and disadvantages were smallest (-1.8 dB, p = 0.047) with both BAHIs mounted on implants. Testbands yielded smaller advantages and higher disadvantages of the additional BAHI (average difference = -0.9 dB).

A synthetic biology-based device prevents liver injury in mice

BACKGROUND & AIMS The liver performs a panoply of complex activities coordinating metabolic, immunologic and detoxification processes. Despite the liver's robustness and unique self-regeneration capacity, viral infection, autoimmune disorders, fatty liver disease, alcohol abuse and drug-induced hepatotoxicity contribute to the increasing prevalence of liver failure. Liver injuries impair the clearance of bile acids from the hepatic portal vein which leads to their spill over into the peripheral circulation where they activate the G-protein-coupled bile acid receptor TGR5 to initiate a variety of hepatoprotective processes. METHODS By functionally linking activation of ectopically expressed TGR5 to an artificial promoter controlling transcription of the hepatocyte growth factor (HGF), we created a closed-loop synthetic signalling network that coordinated liver injury-associated serum bile acid levels to expression of HGF in a self-sufficient, reversible and dose-dependent manner. RESULTS After implantation of genetically engineered human cells inside auto-vascularizing, immunoprotective and clinically validated alginate-poly-(L-lysine)-alginate beads into mice, the liver-protection device detected pathologic serum bile acid levels and produced therapeutic HGF levels that protected the animals from acute drug-induced liver failure. CONCLUSIONS Genetically engineered cells containing theranostic gene circuits that dynamically interface with host metabolism may provide novel opportunities for preventive, acute and chronic healthcare. LAY SUMMARY Liver diseases leading to organ failure may go unnoticed as they do not trigger any symptoms or significant discomfort. We have designed a synthetic gene circuit that senses excessive bile acid levels associated with liver injuries and automatically produces a therapeutic protein in response. When integrated into mammalian cells and implanted into mice, the circuit detects the onset of liver injuries and coordinates the production of a protein pharmaceutical which prevents liver damage.

In Vivo Evaluation of the Phenox CRC Mechanical Thrombectomy Device in a Swine Model of Acute Vessel Occlusion

Mechanical thrombectomy in ischemic stroke is of increasing interest as it is a promising strategy for fast and efficient recanalization. Several thrombectomy devices have been introduced to the armentarium of mechanical thrombectomy. Currently, new devices are under development and are continuously added to the neurointerventional tool box. Each device advocated so far has a different design and mechanical properties in terms of thrombus-device interaction. Therefore, a systematic evaluation under standardized conditions in vivo of these new devices is needed. The purpose of this study was to evaluate the efficiency, thrombus-device interaction, and potential complications of the novel Phenox CRC for distal mechanical thrombectomy in vivo. The device was evaluated in an established animal model in the swine. Recanalization rate, thromboembolic events, vasospasm, and complications were assessed. Radiopaque thrombi (2 cm length) were used for the visualization of thrombus-device interaction during retrieval. The Phenox CRC (4 mm diameter) was assessed in 15 vessel occlusions. For every occlusion a maximum of 3 retrieval attempts were performed. Complete recanalization (TICI 3/TIMI 3) was achieved in 86.7% of vessel occlusions. In 66.7% (10/15), the first retrieval attempt was successful, and in 20% (3/15), the second attempt led to complete recanalization of the parent artery. In 2 cases (13.3%) thrombus retrieval was not successful (TICI 0/TIMI 0). In 1 case (6.7%) a minor embolic event occurred in a small side branch. No distal thromboembolic event was observed during the study. Thrombus-device interaction illustrated the entrapment of the thrombus by the microfilaments and the proximal cage of the device. No significant thrombus compression was observed. No vessel perforation, dissection, or fracture of the device occurred. In this small animal study, the Phenox CRC was a safe and effective device for mechanical thrombectomy. The unique design with a combination of microfilaments and proximal cage reduces thrombus compression with a consequently high recanalization and low complication rate.

In vivo performance of a laser fluorescence device for the approximal detection of caries in permanent molars

OBJECTIVES: The aim of this randomised clinical trial was to investigate if a laser fluorescence device is able to discriminate between sound and carious approximal sites and between enamel and dentinal lesions, as well as to find appropriate cut-off values. METHODS: One hundred and seventeen sound or uncavitated carious sites in permanent molars were visually and radiographically examined, then either opened or not, after which their laser fluorescence was measured. Forty-three lesions were opened, the caries removed and the clinically identified caries depths were registered in addition to the radiographical scoring. Seventy-four sites were radiographically deemed sound or had enamel caries and were not opened. Here, the radiographical scorings were registered. RESULTS: Taking the radiographic scoring as gold standard for all investigated approximal sites, sound sites (D(0), n=40) showed significantly lower laser fluorescence measurements than carious sites (D(1-4), n=77) (Mann-Whitney test, P<0.025) suggesting a cut-off at 7 (sensitivity=0.68, specificity=0.7). Comparing measurements of D(0-2) (n=74) and D(3,4) (n=43), the results were also different by a statistically significant amount (P<0.025) and the cut-off calculated to be 16 (sensitivity=0.6, specificity=0.84). A fair positive correlation between laser fluorescence values and radiographical scoring was found (rho=+0.47, P<0.01). Analysing the 43 opened lesions with their clinically found lesion depths as gold standard, there was a fair positive correlation to the laser fluorescence values (rho=+0.34, P=0.03) and a moderately strong correlation to the radiographic scoring (rho=+0.67, P<0.01). CONCLUSION: The device may be an adjunct tool in the approximal detection of caries along with established procedures.

Treatment of peri-implantitis using an Er:YAG laser or an air-abrasive device: a randomized clinical trial

Non-surgical peri-implantitis therapies appear to be ineffective. Limited data suggest that ER:YAG laser therapy improves clinical conditions. The present study aimed at comparing the treatment effects between air-abrasive (AM) and Er:YAG laser (LM) mono-therapy in cases with severe peri-implantitis.