Faculty Bibliography

The immune-reconstitution syndrome is a paradoxical inflammatory response to a preexisting or a coexisting disease, after the initiation of highly active antiretroviral therapy for the human immunodeficiency virus. Infrequently described, the radiographic and computed tomographic findings of the immune-reconstitution syndrome, which is related to the Mycobacterium avium-intracellulare infection and to highly active antiretroviral therapy, are presented in 2 patients. Homogeneous mediastinal and hilar lymphadenopathy were present in both individuals, with one having a large mass accompanied by small nodules

OBJECTIVE: The aim of this study was to determine the benefit of lower extremity CT venography (CTV) with pulmonary CT angiography (CTA) for diagnosing thromboembolic (TE) disease. SUBJECTS AND METHODS: Reports of all CTAs and CTVs over a 3-year interval (Group I) and CTAs, CTVs, and lower extremity Doppler ultrasounds (US) over a 1 1/2-year subset (Group II) were reviewed. Patient population was inpatients and emergency department patients who were assessed for pulmonary embolism (PE) and deep venous thrombosis (DVT) at a tertiary care hospital. Reported results for CTA or CTV were categorized as positive (CTA(P), CTV(P)), negative (CTA(N), CTV(N)), or indeterminate for PE or DVT. When CTV and US results were discrepant, medical records were reviewed for clinical management. Additional benefit of CTV was assessed by chi-square analysis. RESULTS: In Group I, 737 (81.1%) of 909 CTAs from combined CTA/CTV studies were negative. The diagnosis rate of TE disease increased from 13.0% to 17.3% with the addition of CTV(P)s (P=.01). Of the 119 cases in Group II undergoing combined CTA, CTV, and US, CTV and US were both positive in eight and both negative in 88. Of the seven discordant CTVs and USs with clinical follow-up, five CTVs were positive while USs were negative, three of which were treated clinically for TE disease, while two were considered falsely positive. As CTA also proved positive in one of the three, CTV therefore affected management in two of these five cases and increased the rate of thromboembolism diagnosis from 21.0% to 22.6%; however, this was not significant (P>.05). Two CTV(N)s were managed as false negatives. CONCLUSIONS: The combined use of CTA and CTV significantly increases the rate of TE disease over CTA alone. In cases in which ultrasound is performed, however, there is no significant advantage to performing combined CTA/CTV studies

The educational objectives for this self-assessment module are for the participant to exercise, self-assess, and improve his or her understanding of the imaging evaluation of the solitary pulmonary nodule

A pulmonary fissure is a boundary between the lobes in the lungs. Its segmentation is of clinical interest as it facilitates the assessment of lung disease on a lobar level. This paper describes a new approach for segmenting the major fissures in both lungs on thin-section computed tomography (CT). An image transformation called 'ridge map' is proposed for enhancing the appearance of fissures on CT. A curve-growing process, modeled by a Bayesian network, is described that is influenced by both the features of the ridge map and prior knowledge of the shape of the fissure. The process is implemented in an adaptive regularization framework that balances these influences and reflects the causal dependencies in the Bayesian network using an entropy measure. The method effectively alleviates the problem of inappropriate weights of regularization terms, an effect that can occur with static regularization methods. The method was applied to segment and visualize the lobes of the lungs on chest CT of 10 patients with pulmonary nodules. Only 78 out of 3286 left or right lung regions with fissures (2.4%) required manual correction. The average distance between the automatically segmented and the manually delineated 'ground-truth' fissures was 1.01mm, which was similar to the average distance of 1.03mm between two sets of manually segmented fissures. The method has a linear-time worst-case complexity and segments the upper lung from the lower lung on a standard computer in less than 5min