Detection of pulmonary nodules at paediatric CT: maximum intensity projections and axial source images are complementary.

BACKGROUND: Maximum intensity projection (MIP) images might be useful in helping to differentiate small pulmonary nodules from adjacent vessels on thoracic multidetector CT (MDCT). OBJECTIVE: The aim was to evaluate the benefits of axial MIP images over axial source images for the paediatric chest in an interobserver variability study. MATERIALS AND METHODS: We included 46 children with extra-pulmonary solid organ malignancy who had undergone thoracic MDCT. Three radiologists independently read 2-mm axial and 10-mm MIP image datasets, recording the number of nodules, size and location, overall time taken and confidence. RESULTS: There were 83 nodules (249 total reads among three readers) in 46 children (mean age 10.4 ± 4.98 years, range 0.3-15.9 years; 24 boys). Consensus read was used as the reference standard. Overall, three readers recorded significantly more nodules on MIP images (228 vs. 174; P < 0.05), improving sensitivity from 67% to 77.5% (P < 0.05) but with lower positive predictive value (96% vs. 85%, P < 0.005). MIP images took significantly less time to read (71.6 ± 43.7 s vs. 92.9 ± 48.7 s; P < 0.005) but did not improve confidence levels. CONCLUSION: Using 10-mm axial MIP images for nodule detection in the paediatric chest enhances diagnostic performance, improving sensitivity and reducing reading time when compared with conventional axial thin-slice images. Axial MIP and axial source images are complementary in thoracic nodule detection.

The clinical impact of high resolution computed tomography in patients with respiratory disease.

OBJECTIVE: High resolution computed tomography is widely used to investigate patients with suspected diffuse lung disease. Numerous studies have assessed the diagnostic performance of this investigation, but the diagnostic and therapeutic impacts have received little attention. METHODS: The diagnostic and therapeutic impacts of high resolution computed tomography in routine clinical practice were evaluated prospectively. All 507 referrals for high-resolution computed tomography over 12 months in two centres were included. Requesting clinicians completed questionnaires before and after the investigation detailing clinical indications, working diagnoses, confidence level in each diagnosis, planned investigations and treatments. RESULTS: Three hundred and fifty-four studies on 347 patients had complete data and were available for analysis. Following high-resolution computed tomography, a new leading diagnosis (the diagnosis with the highest confidence level) emerged in 204 (58%) studies; in 166 (47%) studies the new leading diagnosis was not in the original differential diagnosis. Mean confidence in the leading diagnosis increased from 6.7 to 8.5 out of 10 (p < 0.001). The invasiveness of planned investigations increased in 23 (7%) studies and decreased in 124 (35%) studies. The treatment plan was modified after 319 (90%) studies. CONCLUSIONS: Thoracic high-resolution computed tomography alters leading diagnosis, increases diagnostic confidence, and frequently changes investigation and management plans.

Sirolimus-induced pneumonitis following liver transplantation.

Sirolimus-induced pneumonitis has emerged as a potentially serious complication in renal transplantation but only single case reports of this condition have been described after liver transplantation (LT), where experience with sirolimus is relatively limited. We report our experience, the largest to date, of sirolimus-induced pneumonitis following LT. Between 1999 and 2006, 186 liver transplant patients received sirolimus-based immunosuppression, after initial therapy with calcineurin inhibitors (CNIs). All cases of sirolimus-induced pneumonitis were recorded and a retrospective review of the case notes of such patients was undertaken for the purpose of this analysis. Of 186 liver transplant patients receiving sirolimus, 4 (2.2%) developed pneumonitis that was attributed to the drug; the time from starting sirolimus to presentation was varied (1.5-30 months). The most common presenting symptoms were dyspnea, cough and fatigue. The median sirolimus level at the time of diagnosis was 9.7 ng/mL (range, 7-19.5 ng/mL). All patients in the series underwent thoracic computed tomography, which showed similar changes in all patients, and lung biopsy, which revealed features consistent with a drug-induced pneumonitis. In all 4 patients, sirolimus-induced pneumonitis resolved following cessation of therapy but took weeks to months for complete recovery. In conclusion, sirolimus-induced pneumonitis occurred in at least 2% of liver transplant recipients and should be suspected in patients who develop respiratory symptoms while on sirolimus. Although it may be life threatening, early recognition and cessation of sirolimus can lead to complete resolution of pneumonitis.

Ventilation-perfusion scintigraphy to predict postoperative pulmonary function in lung cancer patients undergoing pneumonectomy.

OBJECTIVE: The American College of Chest Physicians (ACCP) recommends using quantitative perfusion scintigraphy to predict postoperative lung function in lung cancer patients with borderline pulmonary function tests who will undergo pneumonectomy. However, previous scintigraphic data were gathered on small cohorts more than a decade ago, when surgical populations were significantly different with respect to age and sex compared with typical lung cancer patients undergoing pneumonectomy in 2005. We therefore revisited the use of V/Q scintigraphy in pneumonectomy patients in predicting postoperative pulmonary function and the appropriateness of current clinical guidelines. CONCLUSION: Contrary to ACCP guidelines, we found that ventilation scintigraphy alone provided the best correlation between the predicted and actual postoperative values and recommend its use to predict postoperative lung function. However, scintigraphic techniques may underestimate postoperative lung function, so caution is required before unnecessarily preventing a patient from undergoing surgery that offers a potential cure.

Use of quantitative lung scintigraphy to predict postoperative pulmonary function in lung cancer patients undergoing lobectomy.

BACKGROUND: In patients with non-small cell lung cancer, the only realistic chance of cure is surgical resection. However, in some of these patients there is such poor respiratory reserve that surgery can result in an unacceptable quality of life. In order to identify these patients, various pulmonary function tests and scintigraphic techniques have been used. The current American College of Physicians and British Thoracic Society guidelines do not recommend the use of quantitative ventilation-perfusion scintigraphy to predict postoperative function in lung cancer patients undergoing lobectomy. These guidelines may have been influenced by previous scintigraphic studies performed over a decade ago. Since then there have been advances in both surgical techniques and scintigraphic techniques, and the surgical population has become older and more female represented. METHODS: We prospectively performed spirometry and quantitative ventilation-perfusion scintigraphy on 61 consecutive patients undergoing lobectomy for lung cancer. Spirometry was repeated one-month postsurgery. Both a simple segment counting technique alone and scintigraphy were used to predict the postoperative lung function. RESULTS: There was statistically significant correlation (p < 0.01) between the predicted postoperative lung function using both the simple segment counting technique and the scintigraphic techniques. However, the correlation using simple segment counting was of negligible difference compared to scintigraphy. CONCLUSIONS: In keeping with current American Chest Physician and British Thoracic Society guidelines, our results suggest that quantitative ventilation-perfusion scintigraphy is not necessary in the preoperative assessment of lung cancer patients undergoing lobectomy. The simple segmenting technique can be used to predict postoperative lung function in lobectomy patients.