Faculty Bibliography

PURPOSE: To identify characteristic features of cytomegalovirus (CMV) pneumonitis at computed tomography (CT), particularly markers that may help differentiate CMV from Pneumocystis carinii pneumonia. MATERIALS AND METHODS: Bronchoalveolar lavage (BAL) and biopsy results in 21 patients with acquired immunodeficiency syndrome, cytopathologic evidence of CMV infection without other infections, and available CT scans were retrospectively evaluated. CT findings were correlated with radiographic and pathologic findings when available. RESULTS: BAL findings were positive for CMV in only six cases, 13 patients had extrathoracic CMV infection, and 10 had Kaposi sarcoma. CT findings included ground-glass attenuation, dense consolidation, bronchial wall thickening or bronchiectasis, and interstitial reticulation without air-space disease (12 patients had discrete pulmonary nodules or masses). Biopsy revealed air-space disease as the dominant process in eight cases. Histopathologic findings correlated well with CT appearances. CONCLUSION: CMV pneumonitis should be suspected in patients with either extrathoracic CMV or documented Kaposi sarcoma, especially when radiographic or CT evidence of pulmonary nodules or masses exists

Intuitively, any technique that minimizes the effects of respiratory motion, eliminates misregistration between scans, minimizes intravenous contrast requirements, and allows high quality multiplanar and 3-D image reconstruction is likely to have a tremendous impact on conventional notions concerning routine thoracic CT. Helical scanning is already of proved efficacy for vascular and airway imaging as well as for identifying and characterizing pulmonary nodules. It may be anticipated that the indications for the use of helical imaging will continue to expand. Of particular interest is the ongoing development of reconstruction algorithms that allow high-quality images to be obtained with rapid table incrementation while simultaneously reducing radiation exposure. Given the intrinsically high contrast of structures within the thorax coupled with the disadvantages that result from respiratory motion, it is not unreasonable to conclude that within the near future volumetric techniques will be the standard for nearly all CT applications within the thorax

PURPOSE: The accessory cardiac bronchus is a rare congenital anomaly of the tracheobronchial tree that arises from the medial wall of the bronchus intermedius. This report documents the computed tomographic (CT) appearance of this anomaly. MATERIALS AND METHODS: Six patients with this anomaly were identified. All six underwent CT; three underwent correlative bronchoscopy, and one had both bronchoscopic and surgical confirmation. RESULTS: In all six cases, a distinct airway could be identified originating from the medial wall of the bronchus intermedius. Associated lung parenchymal tissue was identified in four cases, while in three cases a discrete soft-tissue mass was seen, presumably representing vascularized bronchial or vestigial parenchymal tissue. In two cases, the lumen of the airway was filled with debris. CONCLUSION: Recognition of this anomaly is important, as associated clinical complications, including recurrent episodes of both infection and hemoptysis, may be anticipated in a small percentage of patients

The occurrence of bronchiectasis has only rarely been noted among the protean manifestations of HIV infection in the lungs. We retrospectively identified bronchiectasis on CT scans in 12 HIV + and/or AIDS patients in the absence of either documented mycobacterial infection or a history of prior recurrent pyogenic infection. Pneumonitis was documented in 10 of 12 cases. In eight cases, bronchiectasis was associated with episodes of pyogenic infection; four of these patients also had documented opportunistic infections, including three cases of Pneumocystis carinii pneumonia (PCP). Two patients had infection due solely to PCP. In two cases, bronchiectasis was found in association with one case each of lymphocytic interstitial pneumonitis and nonspecific interstitial pneumonitis, respectively. Although the true incidence of bronchiectasis in this population remains to be established, in our experience bronchiectasis should be considered among the varied pulmonary manifestations of HIV infection. Furthermore, the seemingly rapid development and extent of bronchiectasis in this population suggest an accelerated form of the disease

To meaningfully evaluate factors determining the overall accuracy of computed tomography (CT) for identifying pulmonary nodules, computer-generated nodules were superimposed on normal CT scans and interpreted independently by three experienced chest radiologists. Variables evaluated included nodule size, shape, number, density, location, edge characteristics, and relationship to adjacent vessels, as well as technical factors, including slice thickness and electronic windowing. The overall sensitivity in identifying nodules was 62% and the specificity was 80%. On average, the observers identified 56, 67, and 63% of nodules on 1.5-, 5-, and 10-mm-thick sections, respectively (p = 0.037). Nodules were more difficult to identify on 1.5-mm-thick sections. On average, observers identified 1, 48, 82, and 91% of nodules < 1.5, < 3, < 4.5, and < 7 mm in diameter, respectively (p < 0.001). Other factors that made a significant contribution (p < 0.01) in identifying nodules, as determined by linear discriminant function analysis, included nodule location, angiocentricity, and density. We concluded that computer-generated nodules can be used to assess a large number of imaging variables. We anticipate that this approach will be of considerable utility in assessing the accuracy of interpretation of a wide range of pathologic entities as well as in optimizing three-dimensional scan protocols within the thorax

CT is the imaging method of choice after standard chest radiography for examining patients with suspected bronchiectasis. In most institutions throughout the world, CT has largely eliminated the need for bronchography in the diagnosis of bronchiectasis. Nonetheless, controversy persists concerning the overall accuracy of CT. In an effort to improve overall diagnostic accuracy, we review the wide range of CT appearances of this protean disorder, and emphasize potential problems and technical pitfalls that may arise in routine clinical imaging

The normal range of postoperative imaging findings are described in 34 asymptomatic patients studied 5-66 months (mean, 28 months) after undergoing the continuous-suture graft-inclusion technique for repair of aortic aneurysms (n = 20) and dissections (n = 14) involving the ascending aorta. All 34 patients underwent magnetic resonance (MR) imaging, and 24 patients also underwent computed tomography (CT). Perigraft thickening was seen in 19 patients (56%) with MR imaging and in eight patients (33%) with CT. Flow outside the graft but contained within the native wrap was noted in five patients (15%) with MR imaging and in four patients (17%) with contrast material-enhanced CT. Thrombus was identified outside the graft and within the wrap in seven patients (21%) with MR imaging and in six patients (25%) with CT. Mass effect on the graft was depicted in four patients (12%) with MR imaging and in three patients (13%) with CT. Of the 14 patients who underwent repair of aortic dissections, an intimal flap was seen distal to the graft in seven of the 14 (50%) evaluated with MR imaging and in four of the 10 (40%) evaluated with contrast-enhanced CT. An accurate postoperative imaging evaluation requires precise knowledge of the surgical technique performed and its anatomic consequences