ABSTRACT
Numerous applications in mechanical CAD/CAM need robust algorithms for the identification of protrusion and depression features (DP-features) on geometric models with free-form (B-Spline) surfaces. This paper reports a partitioning algorithm that first identifies the boundary edges of DP-features and then creates a surface patch to cover the depressions or isolate the protrusions. The novelty of the method lies in the use of tangent continuity between edge segments to identify DP-feature boundaries that cross multiple faces and geometries.
Subject(s)
Algorithms , Artificial Intelligence , Image Interpretation, Computer-Assisted/methods , Imaging, Three-Dimensional/methods , Information Storage and Retrieval/methods , Pattern Recognition, Automated/methods , Computer-Aided Design , Equipment Design/methods , Image Enhancement/methodsABSTRACT
Azygography is a useful technique for the pre-operative detection of unresectability of oesophageal malignancies. Invarison of the azygos vein by oesophageal carcinoma occurs because of the anatomic proximity of the thoracic oesophagus and the azygos vein. Azygography may be performed by either intraosseous injection of a rib or by direct retrograde catheterization. Complete obstruction of the azygos vein indicates that an oesophageal carcinoma is unresectable if no other intrathoracic disease is evident.
Subject(s)
Azygos Vein/diagnostic imaging , Esophageal Neoplasms/diagnostic imaging , Angiography/methods , Azygos Vein/anatomy & histology , Catheterization , Esophageal Neoplasms/surgery , Esophagus/anatomy & histology , Humans , RibsABSTRACT
Selective transcatheter arterial embolization was performed in 7 cancer patients with gastrointestinal or uterine bleeding. Most were bleeding from neoplastic tissue and were refractory to conservative management. Complete and permanent cessation of bleeding was obtained in 5 patients, including 3 with gastric bleeding, 1 with colonic bleeding, and in 1 with uterine bleeding. Successful arterial embolization allowed further treatment of the underlying disease which was particularly critical as these patients were poor surgical candidates. No significant or prolonged side effects were noted.
