Haemophilia patients' unmet needs and their expectations of the new extended half-life factor concentrates.

INTRODUCTION: National Member Organisations (NMO) of persons with haemophilia (PWH) from the DACH Region (D = Germany, A = Austria, CH = Switzerland) were interested to better understand PWH's expectations and concerns of extended half-life (EHL) factor concentrates (FC) before availability in these countries. METHODS: Based on an expert meeting and focus groups conducted across Germany a survey for haemophilia patients and their parents was developed and was sent out to 2,644 PWH. RESULTS: One thousand and seven questionnaires were sent back (38.1%); 743 adults and 262 parents. Most patients had haemophilia A (84.5%), were severely affected (73.7%), received prophylaxis (57%) and used recombinant FC (60.2%). One-quarter did not know the correct half-life of their FC [HA/FVIII: 26%, HB/FIX: 31.1%]. Four percent were unsatisfied with their current FC, mainly with short half-life of FC and difficult manageability. They expected from new EHL products less frequent injections (55.2%), better efficacy (32.1%) and safety/no side effects (15.7%); 59.5% would be willing to switch to new products if they have a prolonged half-life and the same safety of the current FC. They wish more information about half-life (84.4%), possible side-effects (81.3%) and efficacy (77%) and wanted to receive information about new products from their haemophilia treater (76.3%) and the newsletter of their NMO (74.3%). Significant differences across countries were found. CONCLUSIONS: The representative survey could show that although PWH were generally satisfied with their current FC, the majority would be willing to switch to EHL products assuming half-life is prolonged and has the same safety of the current FC.

Respiratory motion compensation with tracked internal and external sensors during CT-guided procedures.

This paper investigates the possibility of using the motion of a patient's anterior surface in combination with a motion model to compensate for internal respiratory motion during tracked biopsies. Position data from two electromagnetically tracked sensors, one placed on the patient's sternum, the other incorporated into a biopsy needle, were acquired during a liver biopsy. The data were used to evaluate the correlation between the position measurements of the two sensors and to derive an affine motion model to assess respiratory motion compensation for image-guided interventional procedures. The correlation reached up to 94% for ranges of steady respiration. The residual motion of the internal sensor after compensation is reduced by a factor of approximately four.

3D spatial compounding of ultrasound images using image-based nonrigid registration.

Medical ultrasound images are often distorted enough to significantly limit resolution during compounding (i.e., summation of images from multiple views). A new, volumetric image registration technique has been used successfully to enable high spatial resolution in three-dimensional (3D) spatial compounding of ultrasound images. Volumetric ultrasound data were acquired by scanning a linear matrix array probe in the elevational direction in a focal lesion phantom and in a breast in vivo. To obtain partly uncorrelated views, the volume of interest was scanned at five different transducer tilt angles separated by 4 degrees to 6 degrees. Pairs of separate views were registered by an automatic procedure based on a mutual information metric, using global full affine and thin-plate spline warping transformations. Registration accuracy was analyzed automatically in the phantom data, and manually in vivo, yielding average registration errors of 0.31 mm and 0.65 mm, respectively. In the vicinity of the warping control points, registrations obtained with warping transformations were significantly more accurate than full affine registrations. Compounded images displayed the expected reduction in speckle noise and increase in contrast-to-noise ratio (CNR), as well as better delineation of connective tissues and reduced shadowing. Compounding also revealed some apparent low contrast lobulations that were not visible in the single-sweep images. Given expected algorithmic and hardware enhancements, nonrigid, image-based registration shows great promise for reducing tissue motion and refraction artifacts in 3D spatial compounding.

Automated three-dimensional US frame positioning computed from elevational speckle decorrelation.

For ultrasonographic B-scan images collected by means of a handheld transducer moving in the elevational direction, frame spacings are computed with a speckle-decorrelation algorithm, without additional positioning hardware. Fully developed speckle volumes are automatically segmented and spacing computed from the decorrelation curves. Position accuracy is within 10% for phantoms and 15% for breast studies. The algorithm provides image-based registration, which allows accurate three-dimensional volume rendering.