Multilayer spiral simulation endoscopic imaging is a post-processing of image data obtained from spiral CT volume scans using fast and powerful computer capabilities to reconstruct a three-dimensional image of the inner surface of a cavernous organ, coolly resembling that seen by a fiberoptic endoscope. This technology has made great progress in the clinical application of organs such as colon, large blood vessels, coronary arteries, nasopharynx, larynx, trachea, bile duct, esophagus, stomach, and bladder.
It is easier and more practical in trachea and bronchus. Conventional chest scan shows cross-sectional image, which lacks continuity in observation of bronchial lumen, and it is more difficult to identify bronchus with vertical direction. Simulated bronchial endoscopy is a new technology for 3D imaging of the airway, and its method is to reconstruct a simulated airway image with thin-layer spiral scan data, which can observe the point placed in the trachea! The bronchus can be probed and roamed in the lumen at will, and images similar to those seen by bronchoscopy can be observed, and the images are intuitive and vivid, making this non-invasive imaging technique a new method for evaluating airway lesions.
It generally requires no special preparation and is simple to perform. For elderly patients who have difficulty holding their breath, only simple breathing training is required.
Since 64-layer spiral CT can be performed in a single breath-hold, the entire scanning process can be completed in a very short time of about 6-7 seconds. Only the appropriate layer thickness and pitch need to be adjusted (the thinner the layer thickness and the smaller the pitch, the clearer the image and the higher the spatial resolution).
Image seen.
(1) Normal: smooth luminal surface, clear tracheal rings, shallow grooves between cartilage rings, smooth and sharp tracheal ridges;
(2) Restricted elevation: the wall of the trachea expands into the lumen due to external pressure or tumor infiltration, with a smooth or uneven surface and an obtuse angle with the wall, and the lumen deformation is unevenly narrowed;
(3) Stenosis: High swelling of the tracheal wall, resulting in partial or complete closure of the tracheal lumen;
(4) Intraluminal mass: protruding into the tracheal lumen in the shape of a cauliflower with an acute angle to the wall, with eccentric narrowing or obstruction of the lumen;
(5) swelling: smooth surface of the lumen with thickening and disappearance of the shallow groove between the cartilaginous rings of the tracheobronchus.
Differential diagnosis:
Mucus plug and blood clot
Dilated twisted vascular indentation
Clinical application
①Foreign body in bronchus;
②Bronchial dilatation;
③In the diagnosis of post-traumatic bronchial rupture and post-operative review;
④In the diagnosis of endobronchial tuberculosis;
⑤ observation of bronchial anastomosis after lung transplantation;
⑥Evaluation after tracheal intubation and tracheotomy;
(7) Airway reconstruction after tumor resection;
⑧For those who are not suitable for fiberoptic bronchoscopy;
⑨ for training of fiberoptic bronchoscopists.
Advantages and disadvantages of simulation endoscopy
Advantages.
(1) It is a non-invasive examination, safe and painless for the patient. Especially suitable for patients who cannot tolerate fiberoptic endoscopy
(2) The ability to view the lesion from the distal end of the stenosis or obstruction. This is particularly important for distal bronchial endoscopic imaging, as fiberoptic endoscopy cannot visualize distal bronchial lesions
(3) The ability to visualize lumens that cannot be reached by fiberoptic endoscopy, such as the luminal condition of the pulmonary vessels
(4) can help guide fiberoptic endoscopic biopsy and treatment
(5) It can change the transparency to observe the extra-tubular situation through the lumen
(6) It is helpful to identify whether the lesion is from the lung or from the mediastinum.
Disadvantages.
(1) Poor tissue specificity, cannot be biopsied
(2) The sensitivity of detection of flat lesions needs to be improved, e.g., it is difficult to detect bronchial fibrotic scars due to flat lesions
(3) The color change of the lumen lining and the bacterial situation cannot be observed
(4) Patient breathing and movement artifacts can cause artifacts