Congenital lung lesions: Predictability of lesion type base= on volume analysis using fetal MRI, prenatal sonography and postnatal low=dose thoracic CT angiography

PURPOSE: To compare volumes and growth rates of 3 major types of congenital lung lesions (CLL) and to determine if volume measurement can improve lesion characterizationMATERIALS AND METHODS: Retrospective analysis of 59 infants (0-101days) with pathologically proven CLL was performed. Studies included fetal MRI and prenatal sonography (US) performed the same day at +/- 24.4 weeks gestation, and postnatal CT angiography(CTA). US volumes were extracted from the US reports. Fetal MRI was performed on a 1.5T scanner. CTA studies were acquired in 64-multidetector scanner utilizing a low-dose protocol. Data was transferred to an independent workstation for analysis. Lesion and lung volumes were calculated as described elsewhere. The lesions were classified in 3 main categories: Bronchial atresia (BA), congenital cystic adenomatoid malformation (CCAM), and bronchopulmonary sequestration (BPS), although it should be noted that at least 40% of the lesions suggested more than one histologic type. Statistical analyses was performed using the analysis of variance to identify significant differences in mean lesion volume between groups, intraclass correlation, or Fisher exact tests (P < .05).RESULTS: Mean volumetric MR measurements were as follow: 11.6cc (95%CI 7.7-15.1) for BA, 17.6 cc (95%CI 12.6-22.6) for CCAM, and 21.6cc (95% CI 12.8-229.6) for BPS. The intraclass correlation coefficient between MRI and US measurements for the lesions was 0.94(95% CI 0.87-0.98) for BA and 0.95 (95%CI 0.87-0.95%) for CCAM. On postnatal low-dose CTA the mean volumetric measurements were: 12.1 cc (95%CI 9.3-15.2) for BA, 20.9cc (95%CI 13-28.7) for CCAM and 20.5 cc (95% CI 12.4-28.6) for BPS.CONCLUSION: There is good agreement between BA and CCAM volumes measured by MRI and those measured by US. Despite the literature quotes a peak in CCAM size ocurring approximately at 25 weeks' gestation, in our series, and as measured by postnatal CTA, we encountered a very mild increase in absolute size of CCAM, with relative stable size of BA and slight decrease in volume of BPS. However, all 3 lesions demonstrated a trend toward decreasing mass volume relative to thoracic cavity volume over time. Larger studies are necessary to confirm these results.