Reversed halo sign in pneumocystis pneumonia: a case report

<p>Abstract</p> <p>Background</p> <p>The reversed halo sign may sometimes be seen in patients with cryptogenic organizing pneumonia, but is rarely associated with other diseases.</p> <p>Case presentation</p> <p>We present a case study of a 32-year-old male patient with acquired immunodeficiency syndrome, who had previously been treated with chemotherapy for non-Hodgkin's lymphoma. A chest X-ray showed bilateral patchy infiltrates. High-resolution computed tomography revealed the reversed halo sign in both upper lobes. The patient was diagnosed with pneumocystis pneumonia, which was successfully treated with sulfamethoxazole trimethoprim; the reversed halo sign disappeared, leaving cystic lesions. Cases such as this one are rare, but show that the reversed halo sign may occur in patients who do not have cryptogenic organizing pneumonia.</p> <p>Conclusion</p> <p>Physicians can avoid making an incorrect diagnosis and prescribing the wrong treatment by carefully evaluating all clinical criteria rather than assuming that the reversed halo sign only occurs with cryptogenic organizing pneumonia.</p

Optimal imaging protocol for measuring dynamic expiratory collapse of the central airways

AIM: To compare measurements of expiratory collapse obtained using multidetector computed tomography (MDCT) of the central airways on routine axial and multiplanar reformatted (MPR) images. MATERIALS AND METHODS: Fifty volunteers with normal pulmonary function and no smoking history were imaged using a 64 MDCT system (40 mAs, 120 kVp, 0.625 mm collimation) with spirometric monitoring at end-inspiration and during forced expiration. Measurements of the trachea, right main (RMB) and left main bronchus (LMB) were obtained on axial and MPR images. Inspiratory and dynamic-expiratory cross-sectional area (CSA) measurements were used to calculate the mean percentage expiratory collapse (% Collapse). A paired t-test was used to assess within-subject differences and a Bland-Altman plot was used to assess agreement between the methods. RESULTS: Among 24 men and 26 women (mean age +/- standard deviation 50 +/- 15 years), CSA values were significantly greater on axial than MPR images (all p&lt;0.001); however, the mean difference in % Collapse values for axial versus MPR were small: trachea approximate to 1% (55 +/- 19 versus 56 +/- 18, p = 0.338); LMB identical (60 +/- 20 versus 60 +/- 17 p = 0.856); and, RMB 4% (62 +/- 19 versus 66 +/- 19 p&lt;0.001). On average, creation of MPR required 12 minutes of additional time per case (range = 10-15 min). CONCLUSION: Differences in mean % Collapse for axial versus MPR images were small and unlikely to influence clinical management. This finding suggests that MPR may not be indicated for routine assessment of central airway collapse