<P>Pulmonary involvement is one of the cardinal features of WG, with cough, hemoptysis, and pleuritis being the most common pulmonary symptoms. It is also important to note that up to one third of patients with radiographically visible pulmonary lesions may not have lower airway symptoms.<Sup>2 </<span class="end-tag" />Sup></<span class="end-tag" />P> <P>Until 1990, WG was considered a lethal disease with a mortality of 90% within 2 years. Improvement in the prognosis is primarily related to earlier diagnosis and improved chemotherapeutic treatment strategies that generally include a cytotoxic drug (eg, cyclophosphamide) and glucocorticoids. Even though no speciﬁc radiologic criteria exist, given the appropriate clinical setting, imaging may suggest the diagnosis at an early stage.<Sup>4 </<span class="end-tag" />Sup></<span class="end-tag" />P><P >Chest CT abnormalities in WG have been well-characterized. Typical ﬁndings include multiple nodules, air-space opaciﬁcation, and tracheobroncial disease. Also reported are interstitial ﬁbrosis, pleural effusions, and mediastinal lymphadenopathy. Multiple nodules or masses are the most common pulmonary ﬁnding. They are seen in 70% of patients. The nodules range in size from a few millimeters to 10 cm. The nodules are usually multiple and tend to increase in size and number as the disease progresses, but they rarely exceed 10 in total. Cavitation is common, being seen in approximately 50% of cases and in most nodules >2 cm. Air-ﬂuid levels and calciﬁcation are uncommon. </<span class="end-tag" />P><P >Areas of air-space opaciﬁcation, either consolidation or ground-glass opaciﬁcation, are also common, occurring in 50% of patients. The opaciﬁcation is variable in terms of size, density, and distribution. It may occur with or without the presence of accompanying nodules. Several patterns have been described, including wedge-shaped areas of peripheral consolidation abutting the pleura and mimicking pulmonary infarcts, peribronchoarterial distribution of consolidation, focal consolidation (with or without cavitation), parenchymal bands, and diffuse bilateral areas of ground-glass opaciﬁcation, which represent diffuse pulmonary hemorrhage.<Sup>5 </<span class="end-tag" />Sup></<span class="end-tag" />P><P >The patterns of recurrent WG are as varied as those seen at the initial presentation. Wegener’s granuloma may recur as multifocal or diffuse ground-glass opacities or consolidation, multiple cavitary nodules, and multifocal or long-segment airway stenosis (with or without resultant atelectasis). The recurrent pattern has been reported to be different from the initial pattern; however, according to the study by Lee et al,<Sup>6 </<span class="end-tag" />Sup>both the same and different patterns of recurrence were seen. </<span class="end-tag" />P><P >Several studies have sought to characterize the ﬁndings of sinus CT in WG patients. Some typical bony changes that are indicative of WG include bony obliteration of a sinus, neo-osteogenesis within a sinus, and punctuate bony erosions, primarily at the septum and turbinates. Periantral soft tissue inﬁltration and nodular mucosal thickening are also often seen. The maxillary sinus is the most frequently involved, followed by the frontal and sphenoid sinuses. The bony changes are believed to represent chronic periostitis from the underlying vasculitis. In the appropriate clinical setting, the above changes seen on sinus CT scans may provide radiologic evidence of WG, which can help to expedite diagnosis and improve prognosis.<Sup>1,3,4 </<span class="end-tag" />Sup></<span class="end-tag" />P><P >Treated WG leaves substantial residual damage in the lungs, and high-resolution CT can assist in the distinction between active and inactive lesions. Ground-glass opaciﬁcation, cavitating nodules/masses, and lesions that measure >3 cm typically represent active disease. Noncavitary small nodules and septal or nonseptal linear densities can be either active or cicatricial, residual lesions; however, patients with residual nodules or lines tend to have no more relapses than patients with completely cleared lungs. In the study by Komocsi et al,<Sup>7 </<span class="end-tag" />Sup>all masses resolved in response to treatment, whereas smaller nodules either resolved or remained unchanged. Ground-glass opaciﬁcation is a feature of active disease and typically resolves completely with clinically effective treatment. Cavitation is another prognostically helpful feature, as it typically portends resolution with treatment. Linear densities are impossible to classify prospectively into active or inactive lesions and, therefore, may or may not show response to therapy. Tracheobronchial lesions, such as segments of stenosis as well as intra- and extraluminal soft tissue masses, are also reported to not show improvement with drug treatment.<Sup>7 </<span class="end-tag" />Sup></<span class="end-tag" />P><P >The histologic diagnosis of WG requires identiﬁcation of necrotizing granulomatous vasculitis. The predominant vessels affected are the medium-sized muscular arteries. The necrosis and obliteration of these vessels may result in the radiographic appearances of pulmonary infarcts. However, small-vessel vasculitis sited mainly in alveolar septal capillaries and small arterioles can also be encountered. Capillary involvement is usually found at the edges of the more typical granulomatous vasculitis.<Sup>8 </<span class="end-tag" />Sup></<span class="end-tag" />P><P >Although WG has a well-characterized “classic” presentation, the disease may also have atypical presentations. There have been case reports of WG causing a vasculitis of the main pulmonary arteries and presenting with ﬁndings identical to chronic pulmonary thromboembolic disease.<Sup>9 </<span class="end-tag" />Sup>There is also a rare, “limited” form of WG, in which lung and kidney involvement may be absent. In an even more exceptional presentation, limited WG may appear as Tolosa-Hunt syndrome (painful ophthalmoplegia due to inﬂammation of the cavernous sinus or superior orbital ﬁssure), meningeal and cerebral parenchymal granulomatous inﬂammation, chronic meningitis, and cranial neuropathies.<Sup>10 </<span class="end-tag" />Sup></<span class="end-tag" />P><P ><B>CONCLUSION </<span class="end-tag" />B></<span class="end-tag" />P><P >Wegener’s granulomatosis is a relatively infrequent vasculitis that can cause signiﬁcant morbidity and even mortality. Prompt diagnosis may be possible if its characteristic imaging ﬁndings are recognized in the appropriate clinical setting, and may allow for earlier treatment and improved prognosis. </<span class="end-tag" />P>
Wegener’s granulomatosis. Appl Radiol.