Table 3. Prenatal imaging parameters for prognostic assessment in congenital diaphragmatic hernia.
| Imaging parameter | Acronym | Imaging modality | Technique |
|---|---|---|---|
| Lung to head ratio | LHR | Ultrasound | The ratio of the contralateral lung area (at the level of the cardiac four chamber view) to the head circumference in millimeters. Three lung measurement techniques are described: |
| • Longest diameter method: product of longest diameter of the lung by its longest perpendicular diameter | |||
| • AP method: product of AP lung diameter at mid-clavicular line by perpendicular diameter at AP diameter midpoint | |||
| • Trace method: manual tracing of the lung circumference | |||
| Observed to expected lung to head ratio | o/e LHR | Ultrasound | Lung to head ratio of the contralateral lung is normalized for expected size for gestational age (38) |
| Total fetal lung volume | TFLV | MRI | Sum of three dimensionally measured lung volumes for both lungs |
| Observed to expected total fetal lung volume | o/e TFLV | MRI | The total fetal lung volume is expressed as a percentage of the expected total lung volume using gestational age references (45,46) |
| Percent of predicted lung volume | PPLV | MRI | Expressed as the measured thoracic volume minus measured mediastinal volume (47) |
| Lung volume to body weight ratio | LVBWR | Ultrasound | Lung volume measured by 3-dimensional ultrasound divided by fetal weight estimated by the Hadlock formula |
| Lung to thorax ratio | L/T | Ultrasound | Transverse lung and thoracic area measured at the level of the four-chamber view using the trace method |
| Liver herniation | Liver-up | Ultrasound | Qualitative determination of any liver portion above the diaphragm |
| Percent liver herniation | LiTR; %HL | MRI | Determination of the amount of intrathoracic liver herniation above the plane of the diaphragm expressed in two ways: |
| • LiTR: ratio of intrathoracic liver to total thoracic volume | |||
| • %HL: ratio of intrathoracic liver to total liver volume | |||
| Stomach grading | Cordier | Ultrasound | Position of the stomach assessed on the four‐chamber view of the heart |
| • Grade I: stomach not seen | |||
| • Grade II: next to the apex of the heart, with no structure in between the stomach and the sternum | |||
| • Grade III: stomach visualized along from the apex of the heart and abdominal structures anteriorly | |||
| • Grade IV: stomach with its larger portion posterior to the level of the AV heart valves | |||
| Basta | Ultrasound | In the true axial plane at the level of the four-chamber view of the heart | |
| • Grade I: stomach intraabdominal | |||
| • Grade II: anterior left chest contacting the anterior chest wall | |||
| • Grade III: mid-to posterior chest possibly contacting posterior chest wall | |||
| • Grade IV: retrocardiac with at least a portion of the stomach posterior to the left atrium of the heart within the right chest | |||
| Kitano | MRI | Grade I: stomach intraabdominal | |
| Grade II: left chest intrathoracic | |||
| Grade III: less than half of the stomach herniated into right chest | |||
| Grade IV: more than half of the stomach herniated into the right chest | |||
| Mediastinal shift angle | MSA | MRI | The angle between a sagittal reference line between the posterior surfaces of the vertebral body and the sternum with a line between the vertebral body and the right atrium |
LHR, lung-to-head ratio; AP, antero-posterior; o/e, observed to expected; TFLV, total fetal lung volume; MRI, magnetic resonance imaging; MSA, mediastinal shift angle; PPLV, percentage of predicted lung volume; LVBWR, lung volume to body weight ratio; L/T, lung to thorax; LiTR, liver in thorax ratio; %HL, percent liver herniation; AV, atrioventricular.