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Virtual endoscopy is a technique in which helical-CT and MR data sets are processed by a special software creating a three-dimensional viewing of the inner surface of hollow viscera that simulates the endoscopic view. We report our 2.5-year experience with virtual intraluminal endoscopy (VIE) in the study of the thoracic aorta in patients with aortic dissection and in patients with normal aorta.From December 1997 to June 2000, CT angiography (CTA) data sets of the thoracic aorta obtained in a series of 43 patients were retrospectively evaluated. Our series included 23 patients with clinical or radiological suspicion of aortic dissection and 20 patients in whom the study of the thoracic aorta was carried out as a necessary completion of an abdominal aortic disease. CTA data sets were processed with a dedicated software (Navigator); the view point and view direction could be set arbitrarily in the vessel, obtaining an intraluminal endoscopic view of the inner surface of the vessel. Multiple views were obtained and visualised consecutively through a cine-loop technique. The entire thoracic aorta was studied.VIE enabled correct visualisation of the intimal flap in all cases of aortic dissection (=23) and of its origin at the level of the ascending aorta in 16 cases (Stanford A) and in the descending aorta in the remaining 7 patients (Stanford B). In the control group (=20) no signs of intimal flap were identified with the VIE. In all patients with aortic dissection false and true lumen were entirely visualised. VIE allowed the understanding of the relation between false lumen and supraaortic vessels that originated from the true lumen in all cases and were found to be dissected in 6 patients. In 16 cases the dissection included thoracic and abdominal aorta. In some cases the endoscopic view was altered by artifacts related to the selected threshold levels and represented by pierced surface and floating shape artifacts. A correlation with axial and multiplanar (MPR) images allowed the correct interpretation of such artifacts.According to our experience, virtual endoscopy represents a useful tool in the evaluation of the dissection of the thoracic aorta, allowing a better definition of anatomical details. A correlation with axial images and multiplanar views remains compulsory for a better understanding of VIE findings, which is nevertheless significantly influenced by the operator's experience.

The fibrobullous disease of the upper lobes is an uncommon extraspinal complication of ankylosing spondylitis. We report the conventional radiographic and High Resolution Computed Tomographic (HRCT) findings in the fibrobullous disease of the upper lobes in ankylosing spondylitis. From 1988 to 1994, four patients affected with ankylosing spondylitis, with radiographic involvement of the upper lobes, came to our observation. All patients underwent a chest X-ray exam and the previous chest X-rays carried out 2-25 years earlier were reviewed. Within 15 days, HRCT was performed, during inspiratory apnea. In all cases, repeated bronchoscopies were available, showing bronchial inflammation, together with cytologic tests and bronchial fluid cultures, which revealed no development of mycobacterium tuberculosis. The most frequent CT findings were pleural thickening, fibrotic consolidation and thickening of interlobular septa. Bullae, nodules and ground-glass areas were less frequent findings. The standard chest X-ray exam demonstrated, with the same sensitivity as HRCT, pleural thickening, bullae, nodules and volume loss in the involved lung. However, interlobular septa thickening was depicted only in one case, while bronchiectases and ground-glass areas were not recognized at all. Three temporally distinct patterns of apical involvement (infiltrative, interstitial and fibrobullous) were identified. In conclusion, HRCT was more sensitive and more specific than chest X-rays in the study of the fibrobullous disease of the upper lobes in ankylosing spondylitis.

We report on 31 cases of calcaneal fractures studied with CT according to the latest classification by the Italian Surgical Society of the Foot. Of the utmost importance is the radiologic assessment of the posterior facet and of the underlying bone, which make up the so-called talamus which bears most of the body weight. In our series, talamus fractures were the most frequent ones (26/31 cases): they are characterized by a main sagittal line, running obliquely and dividing the posterior surface and the bone into an anteromedial, or substentacular, fragment and a posterolateral, or tuberosity, fragment. According to fracture severity, the first differential criterion is the presence/absence of displacement and depression (type I fractures the latter, 6 cases in our series, and (types II and III the former, 20/26 cases in our series). Based on the degree of displacement and depression, fractures as classified as type II (10/26 cases) when only the lateral portion of the talamus is displaced and depressed, or as type III (10/26 cases) when the whole talamus is fragmented, displaced and depressed. Moreover, other worsening factors must be considered and B subgroups differentiated in types II and III fractures; these factors are: calcaneus-cuboid facet involvement, lateral wall fragmentation, posterior facet comminution, a small sustentacular fragment and a secondary frontal fracture interrupting the plantar cortex. Extra-talamic fractures, defined as such when isolated, rarely occur. Relative to the anterior apophysis, radiologic attention must be focused on fractures of the dorsal prominence, or beak, which are very often misdiagnosed. As regards the posterior tuberosity, its lateral dislocation must be studied because it may account for calcaneofibular impingement. CT exhibits excellent potentials, provided that slices are thin, acquired on the axial and coronal planes and that, as far as possible, sagittal reconstructions are used, the latter being very useful to depict talamic surface.