Detection of endoleaks after endovascular repair of abdominal aortic aneurysm: value of unenhanced and delayed helical CT acquisitions.

PURPOSE: To assess unenhanced and delayed phase computed tomographic (CT) images combined with arterial phase images for detecting endoleaks after endovascular treatment for abdominal aortic aneurysm (AAA). MATERIALS AND METHODS: CT scans were retrospectively evaluated for the presence of endoleaks after endovascular treatment of AAAs in 33 patients with endoleak (positive group) and 40 patients without evidence of endoleak or aneurysm enlargement (negative group). All patients underwent unenhanced and biphasic contrast material-enhanced CT. The CT scans were reviewed in the following combinations: (a) arterial phase and unenhanced scans (uniphasic/unenhanced set), (b) arterial and delayed phase scans only (biphasic set), and (c) arterial and delayed phase scans with unenhanced scans (complete set). Each set was reviewed by two radiologists blinded to the diagnosis of endoleak. Findings were recorded as positive, negative, or indeterminate for endoleak. RESULTS: Within the positive group, endoleaks were diagnosed with the uniphasic/unenhanced, biphasic, and complete image sets in 30 (91%), 32 (97%), and 33 (100%) patients, respectively. With the uniphasic/unenhanced set, three (9%) endoleaks (seen only on delayed phase images) were missed. With the biphasic set, one (3%) endoleak was interpreted as indeterminate. Within the negative group, uniphasic/unenhanced, biphasic, and complete image sets were negative for endoleaks in 100%, 80%, and 100% of patients, respectively. With the biphasic set, results were indeterminate in 20% of cases. CONCLUSION: A delayed CT acquisition enables detection of additional endoleaks, while an unenhanced acquisition helps eliminate indeterminate results. Thus, both acquisitions contribute to accurate diagnosis of endoleaks when combined with an arterial phase acquisition.

Role of computed tomography in guiding the management of peripheral bronchopleural fistula.

The present study was designed to elucidate whether demonstration of a peripheral bronchopleural fistula on CT correlated with the need for surgical management. We retrospectively identified 33 patients, 24 males and nine females, mean age 38 years, with clinical diagnosis of peripheral bronchopleural fistula and whose chest CT scans and medical charts were reviewed. Each chart was reviewed to identify the cause of the peripheral bronchopleural fistula and its treatment. Treatment decisions were categorized as surgical or conservative. Each chest CT was evaluated for the cause of peripheral bronchopleural fistula as follows: bulla(e), lung abscess/necrotizing pneumonia, neoplasms, peripheral bronchiectasis, and trauma. The peripheral bronchopleural fistula was classified as visible on CT if a distinct channel between the lung or a peripheral bronchus and the pleura was seen on the lung windows. We found that CT was useful in guiding surgery by identifying and localizing the cause of the peripheral bronchopleural fistula in the 55% (18/33) of patients who required surgery. The peripheral bronchopleural fistula or its probable cause was identified in 91% (30/33) as follows: bulla(e) (n = 12), lung abscess/necrotizing pneumonia (n = 11), peripheral bronchiectasis (n = 5), malignancy (n = 1), and posttraumatic pneumatocele (n = 1). The peripheral bronchopleural fistula was right-sided in 24, left-sided in nine, and was visible on CT in 36% (12/33). Among the patients with bullae, 58% (7/12) required surgery; however, the peripheral bronchopleural fistula was visible on CT in only 8% (1/12). Among the 21 patients without bulla(e), the peripheral bronchopleural fistula was visible on CT in 52% (11/21). When the fistula was visible in this subgroup, 73% (8/11) required surgery compared with 30% (3/10) in whom the fistula was not visible (p = NS; Fisher exact). In conclusion, CT was useful in guiding surgery by identifying and localizing the peripheral bronchopleural fistula or its probable cause. Peripheral bronchopleural fistulas caused by bulla(e) were less likely to be visible on CT (p < 0.05). Excluding patients with bulla(e), our data suggest a trend toward the need for surgical management for patients in whom the peripheral bronchopleural fistula was visible on CT.