Collateral ventilation to congenital hyperlucent lung lesions assessed on xenon-enhanced dynamic dual-energy CT: an initial experience.

OBJECTIVE: We wanted to evaluate the resistance to collateral ventilation in congenital hyperlucent lung lesions and to correlate that with the anatomic findings on xenon-enhanced dynamic dual-energy CT. MATERIALS AND METHODS: Xenon-enhanced dynamic dual-energy CT was successfully and safely performed in eight children (median age: 5.5 years, 4 boys and 4 girls) with congenital hyperlucent lung lesions. Functional assessment of the lung lesions on the xenon map was done, including performing a time-xenon value curve analysis and assessing the amplitude of xenon enhancement (A) value, the rate of xenon enhancement (K) value and the time of arrival value. Based on the A value, the lung lesions were categorized into high or low (A value > 10 Hounsfield unit [HU]) resistance to collateral ventilation. In addition, the morphologic CT findings of the lung lesions, including cyst, mucocele and an accessory or incomplete fissure, were assessed on the weighted-average CT images. The xenon-enhanced CT radiation dose was estimated. RESULTS: Five of the eight lung lesions were categorized into the high resistance group and three lesions were categorized into the low resistance group. The A and K values in the normal lung were higher than those in the low resistance group. The time of arrival values were delayed in the low resistance group. Cysts were identified in five lesions, mucocele in four, accessory fissure in three and incomplete fissure in two. Either cyst or an accessory fissure was seen in four of the five lesions showing high resistance to collateral ventilation. The xenon-enhanced CT radiation dose was 2.3 ± 0.6 mSv. CONCLUSION: Xenon-enhanced dynamic dual-energy CT can help visualize and quantitate various degrees of collateral ventilation to congenital hyperlucent lung lesions in addition to assessing the anatomic details of the lung.

[Bronchial atresia. A case report]. / Atrésie bronchique.

Bronchial atresia with mucocele and focal hyperinflation of the lung is a rare anomaly. We report the observation of a 12-year-old girl which presented a right hilar opacity on chest X-ray. The thoracic computed tomography identified an atretic segmental bronchus of the middle lobe with mucocele and focal hyperinflation of the lung. Bronchial endoscopy ruled out any acquired etiology of bronchial obstruction. The definitive diagnosis was bronchial atresia with mucocele and focal hyperinflation of the lung. This uncommon malformation is usually a radiological description. Eighty-four cases were collected in the main series in 1989. Nowadays, about 12 new cases have been published.

[Diagnostic image (23). Congenital lobar emphysema]. / Diagnose in beeld (23). Congenitaal lobair emfyseem.

A 6-months-old-boy failed to thrive. Congenital emphysema of the left upper lobe of the lung was diagnosed, and lobectomy was performed, with good results.