Three-dimensional computed tomography for evaluation and management of children with complex chest wall anomalies: useful information or just pretty pictures?

Advancements in preoperative imaging of pectus excavatum: a comprehensive review

Pectus excavatum, the most common pectus deformity, varies in severity and has been associated with cardiopulmonary impairment and psychological distress. Since its initial documentation, a multitude of imaging techniques for preoperative evaluation (i.e., diagnosis, severity classification, functional assessment, and surgical planning) have been reported. Conventional imaging techniques encompass computed tomography (CT), chest radiography, magnetic resonance imaging (MRI), echocardiography and medical photography, while three dimensional (3D) optical surface imaging is a promising emerging technique in the preoperative assessment of pectus excavatum. This narrative review explores the current insights and advancements of these imaging modalities. CT imaging allows for the calculation of pectus indices and evaluation of cardiac compression and displacement. Recent developments focus on automated calculations, minimizing radiation exposure and improving surgical planning. Chest radiography offers a radiation-reducing alternative for pectus index measurement, but is unsuitable for disproportionally asymmetric chest deformations. MRI is a radiation-free imaging method, and allows for the calculation of pectus indices as well as the assessment of cardiac function. Real-time MRI provides dynamic insights, while exercise MRI shows promise for comprehensive evaluation of cardiac function but requires additional developments. Using echocardiography, structural cardiac changes can be identified, but its use in evaluating cardiac function in pectus excavatum patients is limited. Medical photography combined with caliper measurements complements other imaging methods for qualitative and quantitative documentation of pectus excavatum. Emerging as an innovative technique, 3D optical surface imaging offers a rapid, radiation-free assessment of the deformity which correlates with conventional pectus indices. Potential applications include quantifying other morphological features and predicting cardiac compression. However, standardization and validation are needed for its widespread use. This review provides an overview of preoperative imaging of pectus excavatum, highlighting the current developments in conventional methods and the potential of the emerging 3D optical surface imaging technique. These advancements hold promise for the future of the assessment and surgical planning of pectus excavatum.

Three-dimensional technologies in chest wall resection and reconstruction

Resection and reconstruction of the chest wall can pose unique challenges given its vital role in the protection of the thoracic viscera and the dynamic part it plays in respiration. A number of new three-dimensional (3D) technologies may be invaluable in tackling these challenges. Herein we review the use of 3D technologies in preoperative imaging with virtual 3D models, printing of 3D models for preoperative planning, and printing of 3D prostheses when approaching complex chest wall reconstruction.

Analysis of tissue volume and calcification of the 6th to 8th costal cartilage in 70 woman patients

BACKGROUND

To study the tissue size, calcification characteristics and the correlation between calcification, age, and on whether side of the 6th, 7th, and 8th costal cartilages in women, so as to provide reference for clinical application.

METHODS

A total of 70 cases of female costal cartilage applied with dual-source CT three-dimensional reconstruction were selected from the radiology storage center of Second Xiangya Hospital. The length, width, thickness, calcification rate, calcification degree, calcification type, calcification location, and the relation between calcification, age, and side of bilateral 6th, 7th, and 8th costal cartilages were observed and analyzed on volume reconstruction and maximum density projection images.

RESULTS

(1) The respective length, width, and thickness of 6th, 7th, and 8th costal cartilages on both sides were measured. There were significant differences in length, width, and thickness between unilateral costal cartilages with different ordinal numbers. (2) Significant difference was confirmed in the total calcification types of the 6th, 7th, and 8th costal cartilages. (3) The higher the age, the higher the calcification rate was. The calcification degree of the 6th, 7th, and 8th costal cartilages was higher with the increase of age.

CONCLUSIONS

Preoperative three-dimensional reconstruction and image post-processing of costal cartilage with dual-source CT can accurately measure the amount of cartilage tissue and define the characteristics of calcification, so as to guide the clinical selection of costal cartilage. In female patients of different ages, the calcification rate of costal cartilage increased with age, but no positive correlation was observed.

Chest X-ray Dose Equivalent Low-dose CT with Tin Filtration: Potential Role for the Assessment of Pectus Excavatum

RATIONALE AND OBJECTIVES

To determine the value of chest CT with tin filtration applying a dose equivalent to chest x-ray for the assessment of the Haller index for evaluation of pectus excavatum.

MATERIALS AND METHODS

Two hundred seventy-two patients from a prospective single center study were included and underwent a clinical standard dose chest CT (effective dose 1.8 ± 0.7 mSv) followed by a low-dose CT (0.13 ± 0.01 mSv) in the same session. Two blinded readers independently evaluated all data sets. Image quality for bony chest wall assessment was noted. Radiologists further assessed (a) transverse thoracic diameter, (b) anteroposterior thoracic diameter, and calculated (c) Haller index by dividing transverse diameter by anteroposterior diameter. The agreement of both readers in standard dose and low-dose CT was assessed using Lin's concordance correlation coefficient (p_c).

RESULTS

Subjective image quality was lower for low dose compared to standard dose CT images by both readers (p < 0.001). In total, 99% (n = 540) of low-dose CT scans were rated as diagnostic for bony chest wall assessment by both readers. There was a high agreement for assessment of transverse diameter, anteroposterior diameter and Haller index comparing both readers in standard dose and low-dose CT with p_c values indicating substantial agreement (i.e., 0.95> and ≤0.99) in 12/18 (67%) and almost perfect agreement (i.e., >0.99) in 6/18 (33%).

CONCLUSION

Our study suggests that low-dose CT with tin filtration applying a radiation dose equivalent to a plain chest X-ray is excellent for assessing the Haller index.

Clinical value of 3D SPECT/CT imaging for assessing jaw bone invasion in oral cancer patients

PURPOSE

This study compared the diagnostic accuracy of jaw bone invasion (JBI) of oral cancer observed with three-dimensional (3D) SPECT/CT, CT, and MRI, and evaluated the clinical advantages of 3D SPECT/CT compared to conventional two-dimensional (2D) SPECT/CT.

MATERIALS AND METHODS

From April 2014 to January 2018, consecutive 16 oral cancer patients with suspected JBI, who had preoperatively undergone the imaging tests, were retrospectively enrolled. The likelihood of JBI was independently scored by a radiologist and oral surgeon. Using 2D or 3D SPECT/CT images, 20 oral surgeons delineated virtual surgical areas on 3D-printed jaws for 3 cases in which the extent of JBI was fully pathologically confirmed. The surgeons completed questionnaires regarding surgical planning and explanations for patients using Likert scales.

RESULTS

JBI was found in 9 patients including 5 (56%) with initial bone invasion. 3D SPECT/CT showed very high negative predictive value (100%) and inter-observer agreement (kappa = 0.917). 3D SPECT/CT was more sensitive than CT and MRI when inconclusive findings for JBI were considered negative. Compared to 2D SPECT/CT, 3D SPECT/CT had greater clinical advantages such as surgical planning and explanation to patients (p < 0.005).

CONCLUSION

3D SPECT/CT is useful not only for detecting JBI but also for surgical planning.

A novel technique to measure severity of pediatric pectus excavatum using white light scanning

BACKGROUND/PURPOSE

Computed tomography (CT) derived Haller Index (HI) remains the standard for quantifying severity in patient with pectus excavatum (PE). Optical scanning described in literature reports optimistic results and new indices that correlate with HI. This study assessed the feasibility of a handheld White Light Scanner (WLS) to obtain 3D measurements and indices of PE deformity.

METHODS

From April 2015-April 2017, WLS scanning was conducted by orthotists during clinical visits. Included were children with PE up to 18 years. Analysis assessed correlation of a WLS-derived severity index, Hebal-Malas Index (HMI), with physician measured PE Depth (PED), and CT-derived HI.

RESULTS

Of 195 participants, 185(94%) patients with PE were scanned and 127(69%) had complete WLS data. For 88 patients undergoing monitoring, HMI correlated with PED (r = 0.42, p = 0.004). For 39 patients with pre-operative CT, HMI demonstrated strong correlation with HI (r = 0.87, p<0.0001).

CONCLUSIONS

WLS demonstrated high feasibility of scanning PE. WLS-derived HMI best correlates with HI for patients with severe pectus deformity. Our current data is suggestive that WLS is best applied for severe deformities and yet to be established for milder deformities. Future yearly WLS will provide data on deformity progression and surgical therapy.

LEVEL OF EVIDENCE

IV.

TYPE OF STUDY

Diagnostic Study.

Does an external chest wall measurement correlate with a CT-based measurement in patients with chest wall deformities?

BACKGROUND

Measurements in chest wall deformities are typically conducted using a thorax caliper or a CT scan of the chest wall. This paper focuses on the possible correlation between these two methods to validate the reliability of the thorax caliper, minimize radiation exposure, and limit the usage of expensive imaging techniques.

METHODS

We evaluated 95 consecutive patients (77 pectus excavatum (PE), 17 pectus carinatum (PC), 1 mixed deformity) who received surgical correction of the anterior chest wall. The results of the external chest wall measurements and the CT-based measurements were statistically compared.

RESULTS

A significant correlation between the two measurements was observed in PE and PC at the highest point of the deformation. The strongest correlation was noted in PE. We also noted a correlation between the transverse diameter of the external measurement and the inner thoracic diameter of the CT scan but not for the sagittal diameters in the upper parts of the sternum.

CONCLUSIONS

Thorax caliper measurements are suitable for determining the sagittal thoracic diameter at the maximum level of the deformity and the transverse diameter with an accuracy comparable to that of CT measurements. Since these values key, the thorax caliper is reliable for monitoring and documenting chest wall malformations.

LEVEL OF EVIDENCE

Study of diagnostic test. Testing previously developed diagnostic criteria in a consecutive series of patients and a universally "gold" standard-Level I.

Comparison of endoscopic versus 3D CT derived airway measurements

OBJECTIVES/HYPOTHESIS

To understand: 1) how endoscopic airway measurements compare to three-dimensional (3D) CT derived measurements; 2) where each technique is potentially useful; and 3) where each has limitations.

STUDY DESIGN

Compare airway diameters and cross-sectional areas from endoscopic images and CT derived 3D reconstructions.

METHODS

Videobronchoscopy was performed and recorded on an adult-sized commercially available airway mannequin. At various levels, cross-sectional areas were measured from still video frames using a referent placed via the biopsy port. A 3D reconstruction was generated from a high resolution CT of the mannequin; planar sections were cut at similar cross-sectional levels; and cross-sectional areas were obtained.

RESULTS

At three levels of mechanically generated tracheal stricture, the differences between the endoscopic measurement and CT-derived cross-sectional area were 1%, 0%, and 7% (1.8, 0.8, and 14 mm²). At the vocal folds, the difference was 9% (7.8 mm²). The tip of the epiglottis and width of the epiglottis differed by 27% and 10% (18.73 mm², 0.40 mm). The airway measurements at the base of tongue, minimal cross-sectional area of the pharynx, and choana differed by 26%, 36%, and 30% (101.40 mm², 36.67 mm², 122.71 mm²).

CONCLUSIONS

Endoscopy is an effective tool for obtaining airway measurements compared with 3D reconstructions derived from CT. Concordance is best in geometrically simple areas where the entire cross-section measured is visible within one field of view (trachea, round; vocal folds, triangular) versus geometrically complex areas that encompass more than one field of view (i.e. pharynx, choana).