Bridge to life: the Lifebridge B2T extracorporeal life support system in an in vitro trial.

Extracorporeal life support systems (ECLS) have become common in cardiothoracic surgery, but are still "Terra Incognita" in other medical fields due to the fact that perfusion units are normally bound to cardiothoracic centres. The Lifebridge B2T is an ECLS that is meant to be used as an easy and fast-track extracorporeal cardiac support to provide short-term perfusion for the transport of a patient to a specialized centre. With the Lifebridge B2T it is now possible to provide extracorporeal bypass for patients in hospitals without a perfusion unit. The Lifebridge B2T was tested on three calves to analyze the handling, performance and security of this system. The Lifebridge B2T safely can be used clinically and can provide full extracorporeal support for patients in cardiac or pulmonary failure. Flows up to 3.9 +/- 0.2l/min were reached, with an inflow pressure of -103 +/- 13mmHg, using a 21Fr. BioMedicus (Medtronic, Minneapolis, MN, USA) venous cannula. The "Plug and Play" philosophy, with semi-automatic priming, integrated check-list, a long battery time of over two hours and instinctively designed user interface, makes this device very interesting for units with high-risk interventions, such as catheterisation labs. If a system is necessary in an emergency unit, the Lifebridge can provide a high security level, even in centres not acquainted with cardiopulmonary bypass.

An active contour-based atlas registration model applied to automatic subthalamic nucleus targeting on MRI: method and validation.

This paper presents a new non parametric atlas registration framework, derived from the optical flow model and the active contour theory, applied to automatic subthalamic nucleus (STN) targeting in deep brain stimulation (DBS) surgery. In a previous work, we demonstrated that the STN position can be predicted based on the position of surrounding visible structures, namely the lateral and third ventricles. A STN targeting process can thus be obtained by registering these structures of interest between a brain atlas and the patient image. Here we aim to improve the results of the state of the art targeting methods and at the same time to reduce the computational time. Our simultaneous segmentation and registration model shows mean STN localization errors statistically similar to the most performing registration algorithms tested so far and to the targeting expert's variability. Moreover, the computational time of our registration method is much lower, which is a worthwhile improvement from a clinical point of view.

Automatic prostate segmentation in cone-beam computed tomography images using rigid registration.

We propose to evaluate automatic three-dimensional gray-value rigid registration (RR) methods for prostate localization on cone-beam computed tomography (CBCT) scans. In total, 103 CBCT scans of 9 prostate patients have been analyzed. Each one was registered to the planning CT scan using different methods: (a) global RR, (b) pelvis bone structure RR, (c) bone RR refined by local soft-tissue RR using the CT clinical target volume (CTV) expanded with a 1, 3, 5, 8, 10, 12, 15 or 20-mm margin. To evaluate results, a radiation oncologist was asked to manually delineate the CTV on the CBCT scans. The Dice coefficients between each automatic CBCT segmentation - derived from the transformation of the manual CT segmentation - and the manual CBCT segmentation were calculated. Global or bone CT/CBCT RR has been shown to yield insufficient results in average. Local RR with an 8-mm margin around the CTV after bone RR was found to be the best candidate for systematically significantly improving prostate localization.

Smart suction device for less blood trauma: a comparison with Cell Saver.

OBJECTIVE: The major source of hemolysis during cardiopulmonary bypass remains the cardiotomy suction and is primarily due to the interaction between air and blood. The Smart suction system involves an automatically controlled aspiration designed to avoid the mixture of blood with air. This study was set-up to compare this recently designed suction system to a Cell Saver system in order to investigate their effects on blood elements during prolonged intrathoracic aspiration. METHODS: In a calf model (n=10; mean weight, 69.3+/-4.5 kg), a standardized hole was created in the right atrium allowing a blood loss of 100 ml/min, with a suction cannula placed into the chest cavity into a fixed position during 6 h. The blood was continuously aspirated either with the Smart suction system (five animals) or the Cell Saver system (five animals). Blood samples were taken hourly for blood cell counts and biochemistry. RESULTS: In the Smart suction group, red cell count, plasma protein and free hemoglobin levels remained stable, while platelet count exhibited a significant drop from the fifth hour onwards (prebypass: 683+/-201*10(9)/l, 5 h: 280+/-142*10(9)/l, P=0.046). In the Cell Saver group, there was a significant drop of the red cell count from the third hour onwards (prebypass: 8.6+/-0.9*10(12)/l, 6 h: 6.3+/-0.4*10(12)/l, P=0.02), of the platelet count from the first hour onwards (prebypass: 630+/-97*10(9)/l, 1 h: 224+/-75*10(9)/l, P<0.01), and of the plasma protein level from the first hour onwards (prebypass: 61.7+/-0.6 g/l, 1 h: 29.3+/-9.1 g/l, P<0.01). CONCLUSIONS: In this experimental set-up, the Smart suction system avoids damage to red cells and affects platelet count less than the Cell Saver system which induces important blood cell destruction, as any suction device mixing air and blood, as well as severe hypoproteinemia with its metabolic, clotting and hemodynamic consequences.

Laparoscopic Gastric Banding Outcomes Do Not Depend on Device or Technique. Long-Term Results of a Prospective Randomized Study Comparing the Lapband® and the SAGB®.

BACKGROUND: Gastric banding still represents one of the most widely used bariatric procedures. It provides acceptable weight loss in many patients, but has frequent long-term complications. Because different types of bands may lead to different results, we designed a randomized study to compare the Lapband® with the SAGB®. We hereby report on the long-term results. METHODS: Between December 1998 and June 2002, 180 morbidly obese patients were randomized between Lapband® or SAGB®. Weight loss, long-term morbidity, and need for reoperation were evaluated. RESULTS: Long-term weight loss did not differ between the two bands. Patients who maintained their band had an acceptable long-term weight loss of between 50 and 60 % EBMIL. In both groups, about half the patients developed long-term complications, with about 50 % requiring major redo surgery. There was no difference in the overall rates of long-term complications or failures between the two groups, but patients who had a Lapband® were significantly more prone to develop band slippage/pouch dilatation (13.3 versus 0 %, p < 0,001). CONCLUSIONS: Although in the absence of complication, gastric banding leads to acceptable weight loss; the long-term complication and major reoperation rates are very high independently from the type of band used or on the operative technique. Gastric banding leads to relatively poor overall long-term results and therefore should not be considered the procedure of choice for the treatment of morbid obesity. Patients should be informed of the limited overall weight loss and the very high complication rates.

Ambulatory blood pressure monitoring in the elderly hypertensive patient.

In this retrospective analysis, we assessed the usefulness of ambulatory blood pressure monitoring in the evaluation of elderly hypertensive patients. Thirty-eight untreated and 31 treated hypertensives aged 70 years or more had a systolic blood pressure greater than or equal to 160 mmHg and/or a diastolic blood pressure greater than or equal to 95 mmHg in the clinic. All 69 patients underwent blood pressure monitoring during their customary daily activities using a portable semi-automatic blood pressure recorder (Remier M2000). The mean of all blood pressures obtained with this device was taken as the ambulatory recorded blood pressure. Recorded blood pressures were greater than or equal to 160 mmHg systolic and greater than or equal to 90 mmHg diastolic in 17 untreated and 17 treated patients. In these patients, the introduction of antihypertensive therapy, or its modification, markedly reduced blood pressure during a 4-8 month follow-up. A further 21 untreated and 14 treated patients had recorded blood pressures of less than 160/90 mmHg. The treatment status of these patients was left unchanged for 4-8 months of follow-up. Nevertheless, office blood pressure in these groups, with no change in treatment, decreased significantly during the observation period. At the last visit to the outpatient clinic, there was no significant difference in blood pressure between the four subgroups of patients. Thus, ambulatory blood pressure monitoring appears to be useful in the elderly hypertensive patient in detecting those patients whose blood pressure is elevated only in the clinic. Blood pressure profiles obtained outside the clinic may therefore be useful in making therapeutic decisions in the aged hypertensive.

Optimal culture incubation time in orthopedic device-associated infections: a retrospective analysis of prolonged 14-day incubation.

Accurate diagnosis of orthopedic device-associated infections can be challenging. Culture of tissue biopsy specimens is often considered the gold standard; however, there is currently no consensus on the ideal incubation time for specimens. The aim of our study was to assess the yield of a 14-day incubation protocol for tissue biopsy specimens from revision surgery (joint replacements and internal fixation devices) in a general orthopedic and trauma surgery setting. Medical records were reviewed retrospectively in order to identify cases of infection according to predefined diagnostic criteria. From August 2009 to March 2012, 499 tissue biopsy specimens were sampled from 117 cases. In 70 cases (59.8%), at least one sample showed microbiological growth. Among them, 58 cases (82.9%) were considered infections and 12 cases (17.1%) were classified as contaminations. The median time to positivity in the cases of infection was 1 day (range, 1 to 10 days), compared to 6 days (range, 1 to 11 days) in the cases of contamination (P < 0.001). Fifty-six (96.6%) of the infection cases were diagnosed within 7 days of incubation. In conclusion, the results of our study show that the incubation of tissue biopsy specimens beyond 7 days is not productive in a general orthopedic and trauma surgery setting. Prolonged 14-day incubation might be of interest in particular situations, however, in which the prevalence of slow-growing microorganisms and anaerobes is higher.

Computed tomography commissioning programmes: how to obtain a reliable MTF with an automatic approach?

The purpose of this study was to assess the spatial resolution of a computed tomography (CT) scanner with an automatic approach developed for routine quality controls when varying CT parameters. The methods available to assess the modulation transfer functions (MTF) with the automatic approach were Droege's and the bead point source (BPS) methods. These MTFs were compared with presampled ones obtained using Boone's method. The results show that Droege's method is not accurate in the low-frequency range, whereas the BPS method is highly sensitive to image noise. While both methods are well adapted to routine stability controls, it was shown that they are not able to provide absolute measurements. On the other hand, Boone's method, which is robust with respect to aliasing, more resilient to noise and provides absolute measurements, satisfies the commissioning requirements perfectly. Thus, Boone's method combined with a modified Catphan 600 phantom could be a good solution to assess CT spatial resolution in the different CT planes.

The development of an automatic recognition system for earmark and earprint comparisons

The value of earmarks as an efficient means of personal identification is still subject to debate. It has been argued that the field is lacking a firm systematic and structured data basis to help practitioners to form their conclusions. Typically, there is a paucity of research guiding as to the selectivity of the features used in the comparison process between an earmark and reference earprints taken from an individual. This study proposes a system for the automatic comparison of earprints and earmarks, operating without any manual extraction of key-points or manual annotations. For each donor, a model is created using multiple reference prints, hence capturing the donor within source variability. For each comparison between a mark and a model, images are automatically aligned and a proximity score, based on a normalized 2D correlation coefficient, is calculated. Appropriate use of this score allows deriving a likelihood ratio that can be explored under known state of affairs (both in cases where it is known that the mark has been left by the donor that gave the model and conversely in cases when it is established that the mark originates from a different source). To assess the system performance, a first dataset containing 1229 donors elaborated during the FearID research project was used. Based on these data, for mark-to-print comparisons, the system performed with an equal error rate (EER) of 2.3% and about 88% of marks are found in the first 3 positions of a hitlist. When performing print-to-print transactions, results show an equal error rate of 0.5%. The system was then tested using real-case data obtained from police forces.

Automatic quality assessment in structural brain magnetic resonance imaging

MRI has evolved into an important diagnostic technique in medical imaging. However, reliability of the derived diagnosis can be degraded by artifacts, which challenge both radiologists and automatic computer-aided diagnosis. This work proposes a fully-automatic method for measuring image quality of three-dimensional (3D) structural MRI. Quality measures are derived by analyzing the air background of magnitude images and are capable of detecting image degradation from several sources, including bulk motion, residual magnetization from incomplete spoiling, blurring, and ghosting. The method has been validated on 749 3D T(1)-weighted 1.5T and 3T head scans acquired at 36 Alzheimer's Disease Neuroimaging Initiative (ADNI) study sites operating with various software and hardware combinations. Results are compared against qualitative grades assigned by the ADNI quality control center (taken as the reference standard). The derived quality indices are independent of the MRI system used and agree with the reference standard quality ratings with high sensitivity and specificity (>85%). The proposed procedures for quality assessment could be of great value for both research and routine clinical imaging. It could greatly improve workflow through its ability to rule out the need for a repeat scan while the patient is still in the magnet bore.

Transjugular liver biopsy: prospective evaluation of the angle formed between the hepatic veins and the vena cava main axis and modification of a semi-automated biopsy device in cases of an unfavorable angle.

In cases of transjugular liver biopsies, the venous angle formed between the chosen hepatic vein and the vena cava main axis in a frontal plane can be large, leading to technical difficulties. In a prospective study including 139 consecutive patients who underwent transjugular liver biopsy using the Quick-Core biopsy set, the mean venous angle was equal to 49.6 degrees. For 21.1% of the patients, two attempts at hepatic venous catheterization failed because the venous angle was too large, with a mean of 69.7 degrees. In all of these patients, manual reshaping of the distal curvature of the stiffening metallic cannula, by forming a new mean angle equal to 48 degrees , allowed successful completion of the procedure in less than 10 min.

Bone mineral density (BMD), micro-architecture estimation (TBS) and vertebral fracture assessment (VFA) extracted from a single DXA device in combination with clinical risk factors improve significantly the identification of women at high risk of fracture.

Osteoporosis (OP) is a systemic skeletal disease characterized by a low bone mineral density (BMD) and a micro-architectural (MA) deterioration. Clinical risk factors (CRF) are often used as a MA approximation. MA is yet evaluable in daily practice by the trabecular bone score (TBS) measure. TBS is very simple to obtain, by reanalyzing a lumbar DXA-scan. TBS has proven to have diagnosis and prognosis values, partially independent of CRF and BMD. The aim of the OsteoLaus cohort is to combine in daily practice the CRF and the information given by DXA (BMD, TBS and vertebral fracture assessment (VFA)) to better identify women at high fracture risk. The OsteoLaus cohort (1400 women 50 to 80 years living in Lausanne, Switzerland) started in 2010. This study is derived from the cohort COLAUS who started in Lausanne in 2003. The main goal of COLAUS is to obtain information on the epidemiology and genetic determinants of cardiovascular risk in 6700 men and women. CRF for OP, bone ultrasound of the heel, lumbar spine and hip BMD, VFA by DXA and MA evaluation by TBS are recorded in OsteoLaus. Preliminary results are reported. We included 631 women: mean age 67.4 ± 6.7 years, BMI 26.1 ± 4.6, mean lumbar spine BMD 0.943 ± 0.168 (T-score − 1.4 SD), and TBS 1.271 ± 0.103. As expected, correlation between BMD and site matched TBS is low (r2 = 0.16). Prevalence of VFx grade 2/3, major OP Fx and all OP Fx is 8.4%, 17.0% and 26.0% respectively. Age- and BMI-adjusted ORs (per SD decrease) are 1.8 (1.2-2.5), 1.6 (1.2-2.1), and 1.3 (1.1-1.6) for BMD for the different categories of fractures and 2.0 (1.4-3.0), 1.9 (1.4-2.5), and 1.4 (1.1-1.7) for TBS respectively. Only 32 to 37% of women with OP Fx have a BMD < − 2.5 SD or a TBS < 1.200. If we combine a BMD < − 2.5 SD or a TBS < 1.200, 54 to 60% of women with an osteoporotic Fx are identified. As in the already published studies, these preliminary results confirm the partial independence between BMD and TBS. More importantly, a combination of TBS subsequent to BMD increases significantly the identification of women with prevalent OP Fx which would have been misclassified by BMD alone. For the first time we are able to have complementary information about fracture (VFA), density (BMD), micro- and macro architecture (TBS and HAS) from a simple, low ionizing radiation and cheap device: DXA. Such complementary information is very useful for the patient in the daily practice and moreover will likely have an impact on cost effectiveness analysis.