Bronchial anatomy is adequately demonstrated with the appropriate spiral computed tomographic technique on cross-sectional images, multiplanar reconstruction images, and three-dimensional reconstruction images. Contrary to the numerous variations of lobar or segmental bronchial subdivisions, abnormal bronchi originating from the trachea or main bronchi are rare. Major bronchial abnormalities include accessory cardiac bronchus (ACB) and "tracheal" bronchus. An ACB is a supernumerary bronchus from the inner wall of the right main bronchus or intermediate bronchus that progresses toward the pericardium. Fourteen ACBs were found in 17,500 consecutive patients (frequency, 0.08%). The term tracheal bronchus encompasses a variety of bronchial anomalies originating from the trachea or main bronchus and directed to the upper lobe. In a series of 35 tracheal bronchi, only eight originated from the trachea, three originated from the carina, and 24 originated from the bronchi. Displaced tracheal bronchi (27 of 35) are more frequent than supernumerary tracheal bronchi (eight of 35). Minor bronchial abnormalities include variants of tracheal bronchus, displaced segmental bronchi, and bronchial agenesis. The main embryogenic hypotheses for congenital bronchial abnormalities are the reduction, migration, and selection theories. Knowledge and understanding of congenital bronchial abnormalities may have important implications for diagnosis, bronchoscopy, surgery, brachytherapy, and intubation.
Multi-detector row CT with reconstructed scans of 1.25-mm-thick sections enables accurate analysis of peripheral pulmonary arteries down to the fifth order on spiral CT angiograms.
Six of 11 signs were good predictors of blunt diaphragmatic rupture. Despite diaphragmatic thickening, focal defect and segmental nonrecognition had 100% cumulative sensitivity; the reviewers formulating the diagnosis before analyzing CT signs overlooked blunt diaphragmatic rupture on CT in 12.5-43.8% of the patients.
Percutaneous ablation is a well-established technique for treating cardiac arrhythmia by removing or isolating tissue at the site of the abnormal impulse formation. Various forms of energy for ablation procedures may be delivered via a catheter with fluoroscopic guidance. The procedures most commonly performed are radiofrequency ablation and cryotherapy. Atrial fibrillation, the most frequently occurring supraventricular tachyarrhythmia, may be initiated by ectopic beats that originate in the ostia of the pulmonary veins. The clinical efficacy of isolation (or focal ablation) of the pulmonary veins for treatment of atrial fibrillation has been well demonstrated. Pre- and postprocedural examinations with computed tomography (CT) or magnetic resonance (MR) imaging are frequently performed to depict the anatomy and to obtain baseline measurements of the pulmonary veins to enable early detection of complications from ablation. Venous stenosis or thrombosis and pulmonary hypertension may occur after radio-frequency ablation. Familiarity with the appearance of normal anatomic variants at CT and MR imaging and with the normal range of pulmonary vein diameters is essential for preoperative management and early detection of procedure-related complications.
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