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.

The Role of Prenatal Target Ultrasonography in the Diagnosis of Congenital Anomalies in Infants of Diabetic Mothers / 대한주산의학회잡지

OBJECTIVE: Infants of diabetic mothers have higher incidence of congenital malformations compared with those of non-diabetic mothers. We investigated the usefulness of prenatal level II or "targeted" ultrasonography (TUS) as a diagnostic tool to identify congenital abnormalities in infants of diabetic mothers. METHODS: We retrospectively reviewed the medical records of 218 mothers diagnosed as pregestational or gestational diabetes in whom prenatal TUS was performed in Asan Medical Center between 2004 and 2009. The prenatal TUS findings were compared with the congenital abnormalities found in the infants (n=226) of the diabetic mothers by physical examination and ultrasonography (including echocardiography). Maternal risk factors associated with congenital anomalies were also investigated. RESULTS: The incidence of congenital anomalies was 14.2% (n=32) in prenatal TUS and 15.5% (n=35) postnatally, respectively. Only 7 cases (3.6%) out of the 194 infants with normal prenatal TUS findings were found to have congenital abnormalities diagnosed postnatally. All of the abnormalities in these 7 infants could be detected or suspected by physical examination after birth. Maternal fasting glucose level >120 mg/dL and insulin therapy were significant risk factors for predicting congenital abnormalities in infants of diabetic mothers. CONCLUSION: Prenatal TUS performed by experienced obstetricians had a good reliability in the diagnosis of congenital anomalies in infants of diabetic mothers. Need for universal screening of ultrasound or echocardiography in these infants should be questioned especially in the cases in which prenatal TUS was performed.