Stereoscopic images from computed tomography angiograms

Objective To present an adaptation of the anaglyph photography technique to be used with radiological images from computed tomography angiograms, enabling stereoscopic visualization of a patient's individual abnormal vascular anatomy for teaching, case discussion, or surgical planning purposes. Methods Traditional anaglyph procedures with actual objects yield 2 independent photographs, simulating the image perceived by each eye. Production of anaglyphs from angiograms involve 3 basic procedures: volume rendering, image capture, and image fusion. Volume renderings were reconstructed using a free, open-source DICOM (Digital Imaging and Communications in Medicine) reader. Subsequently, the virtual object was positioned to mimic the operator's angle of view, and different perspectives of the reconstructed volume could be obtained through exclusively horizontal rotation. The 2 images were then fused after their color composition was modified so that each eye would perceive only 1 image when using anaglyph glasses. Results Forty-three angiograms were reviewed for the purpose of this study and a total of 6 examinations were selected for illustration of the technique. Stereoscopic display was possible for all of them and in the 3 types of support tested: computer monitor, tablet, and smartphone screens. Conclusions Anaglyph display of computed tomography angiograms is an effective and low-cost alternative for the stereoscopic visualization of a patient's individual intracranial vascular anatomy.