Malignant ectomesenchymoma of the nose. Case report and review of the literature.

To the best of our knowledge, a malignant ectomesenchymoma of the nose has not yet been reported. This rare tumour is composed of a mesenchymal element--usually a rhabdomyosarcoma--and a neuroectodermal element, often a neuroblastoma or a malignant schwannoma. Most malignant ectomesenchymomas have been found in children (mainly boys), but 5 adult cases, including our case, have also been reported. A 62-year-old man presented with a nasal obstruction on the right side of the nose. Diagnostic nasal endoscopy revealed a mass in the dorsal part of the right nasal cavity, which was treated by endoscopic surgery. The postoperative course was uneventful, and subsequent radiotherapy well tolerated. Since rhabdomyosarcoma is the most common component of this neoplasm, the treatment protocol for rhabdomyosarcoma would have appeared appropriate. This report reviews the literature, summarises the pathological features and possible histogenesis of the tumour, and outlines recommended treatments for malignant ectomesenchymoma.

Interactive PC-based volume rendering of CT datasets.

In radiology, the reading of large CT volumes is a time consuming task. Interactive volume rendering (iVRT) is a promising new technique. Using dedicated hardware (VP1000, Terarecon Inc.) it can now be realized on a standard PC in a cost effective manner. For this purpose, a program built using the Visualization Toolkit with integrated functionality for the VP 1000 is used for almost real-time iVRT (8-9 frames/second). It is possible to embed opaque and translucent polygon surfaces (e.g., segmented structures). By interactively varying the opacity, color and gradient transfer functions as well as using freely placable cutting planes, the visualization can easily be adapted to different diagnostic needs.

Visualization of anatomical structures of epigastric organs by use of automatically segmented 3-D ultrasound image volumes--first results.

The detection and the staging of tumors and their metastases in parenchymatous organs of the epigastric organs today is improved by the enormous increase of imaging system's efficiency. For an increasing number of findings, which shall be dissected in intention to cure, the feasibility of diagnostics and therapy-planning based on sonograms was investigated. In 3-D US image volumes of approx. 20 patients, characteristic anatomical structures (e.g., vessels, abscesses, tumors) were detected by specifically adapted automatic computer-based segmentation and visualized. The detection of pathological findings, their quantification and their spatial assignment to anatomical main structures was essentially simplified by 3-D image acquisition and 2-D and 3-D visualization of segmented images.

3-D visualization of the newborn's hip joint using ultrasound and automatic image segmentation.

Graf's method has been established as a standardized procedure for the diagnostic screening of developmental dysplasia of the hip in newborns. In this procedure, a two dimensional ultrasound image that has to contain standardized landmarks is taken and evaluated interactively to calculate congruence indicators. Since these indicators are only derived from a 2-D scan, they do not reflect the spatial joint structure. In our study, we visualized three dimensional scans of newborns' hip joints that were obtained using a conventional ultrasound transducer and a commercial localizer system that was fixed to the scanhead. The landmarks were detected by automatic image segmentation to avoid examiner dependent findings. The landmark structures as well as an automatically determined virtual sphere approximating the femoral head were visualized color coded on a computer screen. This kind of visualization was found to be intuitive. The evaluation of the entire joint geometry and the 3-D relations between the acetabulum and the femoral head improves the reliability of the diagnostics.

Pilot study of total knee arthroplasty planning by use of 3-D ultrasound image volumes.

The incidence of Total Knee Arthroplasties (TKA) is increasing. The main problem is the correct placement of especially the femoral prosthesis. Pre-operative planning and intra-operative realization relies on lower limb X-rays and extra- or intramedullary devices. This may lead to implant displacements. We generated virtual models of the distal femur for 10 knee joints. In a free-hand sweep we recorded 3-D US image volumes, which typically took 90 sec. The bony structures were detected automatically in the US-images and then appeared as curvilinear lines. Spatially arranged these lines formed femur models, which were used for the placement of a femoral prosthesis in an interactive computer-based 3-D planning. The automatic image segmentation took about 45 minutes. Its analysis showed correct detection of the bone surface. The interactive planning took 5-10 minutes. The investigation demonstrates that 3-D US can provide data of position and size of bony structures. Bone models created by analysis of 3-D US image volumes are useable for simulation of TKA implantations.

[New approaches to 3D-ultrasonographic imaging of infant hips]. / Neue Ansätze zu einer 3D-sonographischen Darstellung der Säuglingshüfte.

Ultrasound of the infant hip is an established method in the diagnosis and monitoring of the treatment of congenital dysplasia of the hip (CDH). Its use as a screening method for CDH, early diagnosis and start of therapy results in a high success rate and reduces the length of the therapy. According to Graf's technique, the examination findings are taken from a standard plane. Assessment of the examined hip joint is based on information obtained from this standard intersection plane, which has to be representative for the whole joint configuration. Furthermore, the method according to Graf requires a very expert examiner. We report on a new approach to three dimensional ultrasound of the infant hip for covering and demonstrating the complete dimensions of CDH. A maturity disorder of the infant hip located outside the standard plane should be recognized by 3D ultrasound. In contrast to already existing 3D ultrasound systems with specially constructed transducers, we use a position sensor which, in conjunction with a video tape recorder, an external computer and the corresponding software, is able to support normal ultrasound equipment. A common 7.5 or 5 Mhz linear transducer can be used. During the examination, the form and size of the femoral head is automatically analysed. The result is placed as a virtual sphere into the 3D data set. The quality of the examination should be independent of the examiner's skill.