Original scientific paper
Virtual colonoscopy and 3D reconstruction in colorectal cancer patients
Stanko Belina
; Department of Radiology, Special Hospital for Medical Rehabilitation, Krapinske Toplice, Croatia
Višeslav Ćuk
; Department of Otorhinolaryngology, General Hospital Zabok, Zabok, Croatia
Abstract
Introduction: Virtual endoscopy of the colon or virtual colonoscopy (VC) is a technique for postprocessing high resolution helical CT datasets. 3D surface rendering volume reconstruction that simulates endoscopic views of the inner surface of the colon was performed in real time by means of computer generated ray casting. VC may be performed together with 3D volume rendering (3DVR). VC can be applied in teaching, diagnostics, intervention planning or intraoperative navigation and as a non-invasive technique it is particularly useful when the patient cannot tolerate classical fiberoptic endoscopy.
Objectives: To implement VC as a new technique of high resolution helical CT data postprocessing in screening, preoperative diagnostics and management and to discuss advantages and disadvantages of the method.
Methods: VC and 3DVR in space analysis were performed using Syngo 2006G platform by Siemens Medical Systems in: a 46-year-old man with a spastic colon and some intestinal diverticula and polyps, a 65-year-old man who underwentendoscopic removal of a large colorectal polyp, a 64-year-old women with large circular cancer stenosis of the rectum and right hepatic lobe metastatic lesion, and a 52-year-old man with a large endoluminal cancer mass in the sigmoid colon. Virtual colonoscopy was performed in real time using ray casting algorithm with space leaping acceleration method. Siemens Somatom Emotion 16 scanner was used for image acquisition. Postprocessing of the images stored in DICOM format was done by dual Xeon workstation.
Results: Fly through algorithm and 3DVR were performed on data sets created from axial CT images collected from multislice helical CT scanner archived in DICOM format. Fly through and 3DVR postprocessing produced a series of images that were analyzed by one radiologist, two surgeons and two physicians experienced in virtual endoscopy.
Conclusion: VC is a useful non-invasive method in the assessment of malignant and benign lesions of colon. It may provide useful additional information for a surgeon during preoperative management. Furthermore, it allows three dimensional visualization in the lumen beyond areas of narrowing or stenosis and it gives a highly accurate representation of colorectal lesions. Its disadvantages are that it does not provide histology, it requires an air-mucosa interface to produce an image and it cannot identify functional lesions. Using VC, clinicians can appreciate not only the intraluminal proliferation of the tumor but also the extraluminal extension of the mass and its relation to the surrounding organs.
Keywords
high resolution computed tomography; virtual colonoscopy; 3D volume rendering; colorectal cancer
Hrčak ID:
280405
URI
Publication date:
22.11.2007.
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