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Biomedical subjects

R H Knapp

Publications and source records attributed to R H Knapp.

28 records · Page 2Linked to original sources

Three-dimensional computed tomography of the foot: optimizing the image.

The complex anatomy of the foot can be imaged using high resolution computed tomography. High resolution serial nonoverlapping CT scans of foot anatomy have a high degree of soft tissue contrast, and excellent geometrical accuracy (no magnification error). Three-dimensional surface reconstruction from CT scans of the foot were performed using specially developed computer software. These surface reconstructions display the osseous and soft tissue anatomy of the foot in a form similar to anatomic preparations. The removal of overlying skin, disarticulation of the ankle, tarsals and metatarsals was accomplished using computer methods. Major factors necessary to optimize three-dimensional images are presented and illustrated. The technique has been applied in living subjects with arthritis, carpal coalitions, osteochondritis dissecans, and fractures. These images have been useful in communicating the findings on high resolution CT scans to referring clinicians, correlating CT findings in areas of complex anatomy, and eliminating overlying or obscuring structures by mathematically disarticulating the foot and individual tarsal bones.

Cadaver↗

Three-dimensional surface reconstruction of the carpal bones from CT scans: transaxial versus coronal technique.

Computer methods for reconstruction of three-dimensional (3-D) images from standard CT scans have been developed. The process does not require special computer knowledge and can be performed with a unmodified CT scanner. 3-D images are especially valuable for conveying information to nonradiologist physicians, who are unfamiliar with the numerous slice-format images produced in a standard CT examination. The utility of these methods for clarification of areas of complex skeletal anatomy has been previously demonstrated in the literature. We performed 3-D imaging on a normal isolated cadaver hand and on a patient with scaphoid fracture. In both cases the 3-D images obtained had excellent osseous anatomical detail. A method of acquisition of high quality wrist CT scans, suitable for 3-D processing, is suggested.

Cadaver↗

Three-dimensional magnetic resonance imaging of the heart.

Three-dimensional surface images of the human heart may be produced from magnetic resonance imaging. These examinations are used in the evaluation of congenital heart disease for preoperative planning and postoperative evaluation. Computer graphics software has been adapted to produce three-dimensional images of the beating heart from contiguous two-dimensional serial EKG-triggered magnetic resonance image data sets. The natural boundary between flowing blood and cardiac tissue serves to outline cardiac structures. The techniques for producing these images and pitfalls in the operation of the system as well as examples of their application to the study of patients with congenital heart disease are outlined in this article.

Adolescent↗

Generation of three dimensional images from CT scans: technological perspective.

Routine production of three dimensional (3-D) surface images from CT scans for clinical applications has been performed in 700 cases. These images have been found useful in craniofacial, orthopedic, and neurosurgical applications. Three dimensional images may be produced on the same CT scanner that collected the original slices. The emergence of 3-D imaging as a routine radiological procedure involves special technological requirements to avoid artifacts and to produce a useful result. Three dimensional surface reconstruction procedures are reviewed and examples of clinical application are presented.

Adult↗