Cost-effective fetal lung volumetry for assessment of congenital diaphragmatic hernia

Anatomic evaluation of Pancoast tumors using three-dimensional models for surgical strategy development

OBJECTIVE

Pancoast tumor resection planning requires precise interpretation of 2-dimensional images. We hypothesized that patient-specific 3-dimensional reconstructions, providing intuitive views of anatomy, would enable superior anatomic assessment.

METHODS

Cross-sectional images from 9 patients with representative Pancoast tumors, selected from an institutional database, were randomly assigned to presentation as 2-dimensional images, 3-dimensional virtual reconstruction, or 3-dimensional physical reconstruction. Thoracic surgeons (n = 15) completed questionnaires on the tumor extent and a zone-based algorithmic surgical approach for each patient. Responses were compared with surgical pathology, documented surgical approach, and the optimal "zone-specific" approach. A 5-point Likert scale assessed participants' opinions regarding data presentation and potential benefits of patient-specific 3-dimensional models.

RESULTS

Identification of tumor invasion of segmented neurovascular structures was more accurate with 3-dimensional physical reconstruction (2-dimensional 65.56%, 3-dimensional virtual reconstruction 58.52%, 3-dimensional physical reconstruction 87.50%, P < .001); there was no difference for unsegmented structures. Classification of assessed zonal invasion was better with 3-dimensional physical reconstruction (2-dimensional 67.41%, 3-dimensional virtual reconstruction 77.04%, 3-dimensional physical reconstruction 86.67%; P = .001). However, selected surgical approaches were often discordant from documented (2-dimensional 23.81%, 3-dimensional virtual reconstruction 42.86%, 3-dimensional physical reconstruction 45.24%, P = .084) and "zone-specific" approaches (2-dimensional 33.33%, 3-dimensional virtual reconstruction 42.86%, 3-dimensional physical reconstruction 45.24%, P = .501). All surgeons agreed that 3-dimensional virtual reconstruction and 3-dimensional physical reconstruction benefit surgical planning. Most surgeons (14/15) agreed that 3-dimensional virtual reconstruction and 3-dimensional physical reconstruction would facilitate patient and interdisciplinary communication. Finally, most surgeons (14/15) agreed that 3-dimensional virtual reconstruction and 3-dimensional physical reconstruction's benefits outweighed potential delays in care for model construction.

CONCLUSIONS

Although a consistent effect on surgical strategy was not identified, patient-specific 3-dimensional Pancoast tumor models provided accurate and user-friendly overviews of critical thoracic structures with perceived benefits for surgeons' clinical practices.

Motion corrected fetal body MRI provides reliable 3D lung volumes in normal and abnormal fetuses

Objectives

To calculate 3D‐segmented total lung volume (TLV) in fetuses with thoracic anomalies using deformable slice‐to‐volume registration (DSVR) with comparison to 2D‐manual segmentation. To establish a normogram of TLV calculated by DSVR in healthy control fetuses.

Methods

A pilot study at a single regional fetal medicine referral centre included 16 magnetic resonance imaging (MRI) datasets of fetuses (22–32 weeks gestational age). Diagnosis was CDH (n = 6), CPAM (n = 2), and healthy controls (n = 8). Deformable slice‐to‐volume registration was used for reconstruction of 3D isotropic (0.85 mm) volumes of the fetal body followed by semi‐automated lung segmentation. 3D TLV were compared to traditional 2D‐based volumetry. Abnormal cases referenced to a normogram produced from 100 normal fetuses whose TLV was calculated by DSVR only.

Results

Deformable slice‐to‐volume registration‐derived TLV values have high correlation with the 2D‐based measurements but with a consistently lower volume; bias −1.44 cm³ [95% limits: −2.6 to −0.3] with improved resolution to exclude hilar structures even in cases of motion corruption or very low lung volumes.

Conclusions

Deformable slice‐to‐volume registration for fetal lung MRI aids analysis of motion corrupted scans and does not suffer from the interpolation error inherent to 2D‐segmentation. It increases information content of acquired data in terms of visualising organs in 3D space and quantification of volumes, which may improve counselling and surgical planning.

What's already known about this topic?

Congenital diaphragmatic hernia (CDH) and congenital lung lesions (CLL) are prognosticated with ultrasound‐based measurements of the fetal lung in a single dimension; however true volumes may provide greater sensitivity for high risk cases. Current use of magnetic resonance imaging (MRI) to calculate fetal lung volumes is limited as two‐dimensional segmentation is labour intensive and risks interpolation and motion‐corruption errors.

What does this study add?

Three‐dimensional lung volumes can be computed from deformable slice‐to‐volume registration (DSVR) 3D reconstructions and highly correlate with traditional 2D‐derived volumes. DSVR‐derived volumes, however, should be more reliable owing to higher resolution and semi‐automated calculations that do not rely on interpolation between slices on motion‐corrupted stacks.