Diagnostic accuracy of imaging studies in congenital lung malformations

BACKGROUND: Although fetal ultrasound, fetal MRI and postnatal CT are now widely used in the evaluation of congenital lung malformations (CLM), their diagnostic accuracy remains undefined. OBJECTIVE: To correlate prenatal and postnatal imaging studies with pathological data after CLM resection. DESIGN: Retrospective, descriptive case series study. SETTING: A North American tertiary care centre. PATIENTS: One hundred and three consecutive lung resections for a suspected CLM between 1 January 2005 and 31 December 2015. MAIN OUTCOME MEASURES: Diagnostic accuracy of imaging diagnosis compared with pathological evaluation. RESULTS: Pathological diagnoses included congenital pulmonary airway malformation ((CPAM) n=45, 44%), bronchopulmonary sequestration (BPS; n=25, 24%), CPAM/BPS hybrid lesions (n=22, 21%) and pleuropulmonary blastoma (n=2, 2%). Fetal ultrasound detected 85 (82.5%) lesions and correctly diagnosed whether or not a lesion was a CPAM in 75% of cases (sensitivity 93%, specificity 32%). Fetal MRI had a similar concordance rate (73%) but was superior in correctly determining whether a systemic feeding vessel was present in 80% of cases (sensitivity 71%, specificity 88%) compared with an ultrasound accuracy rate of 72% (sensitivity 49%, specificity 93%). By comparison, postnatal CT correctly diagnosed whether a CPAM was present in 84% of cases (sensitivity 86%, specificity 77%) and whether a systemic feeding vessel was present in 90% of cases (sensitivity 92%, specificity 88%). CONCLUSIONS: Fetal ultrasound remains an important tool in the detection and evaluation of congenital lung malformations. However, it does not correctly predict histology in approximately 25% of prenatally detected CLMs and remains limited by relatively poor sensitivity for systemic feeding vessels pathognomic for a bronchopulmonary sequestration. These data suggest the importance of obtaining additional cross-sectional imaging, preferably a postnatal CT scan, in all patients to help counsel families and to guide in the optimal management of these lesions.