Rosaline Zhang1, Hyunyeol Lee2, Xia Zhao2, Hee Kwon Song2, Arastoo Vossough3, Felix W Wehrli2, Scott P Bartlett4. 1. Division of Plastic Surgery, Children's Hospital of Philadelphia, University of Pennsylvania, Buerger Center, 3500 Civic Center Boulevard, Philadelphia, PA 19104. 2. Department of Radiology, University of Pennsylvania, Philadelphia, PA. 3. Department of Radiology, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA. 4. Division of Plastic Surgery, Children's Hospital of Philadelphia, University of Pennsylvania, Buerger Center, 3500 Civic Center Boulevard, Philadelphia, PA 19104. Electronic address: bartletts@email.chop.edu.
Abstract
RATIONAL AND OBJECTIVES: Computed tomography (CT) is the clinical gold-standard for high-resolution 3D visualization of cortical bone structures. However, ionizing radiation is of concern, particularly for pediatric patients. This study evaluates the feasibility of producing 3D human skull renderings using a novel bone-selective magnetic resonance imaging technique. MATERIALS AND METHODS: A dual-radiofrequency pulse, dual-echo, 3D ultrashort echo time sequence was applied for scanning of a cadaver skull and five healthy adult subjects. Scans were each completed within 6 minutes. Semiautomatic segmentation of bone voxels was performed using ITK-SNAP software, leading to 3D renderings of the skulls. For comparison, thin-slice head CT scans were performed. Mimics software was used to measure eight anatomic distances from 3D renderings. Lin's Concordance Correlation test was applied to assess agreement between measurements from MR-based and CT-based 3D skull renderings. RESULTS: The 3D rendered MR images depict most craniofacial features (e.g., zygomatic arch), although some voxels were erroneously included or excluded in the renderings. MR-based measurements differed from CT-based measurements by mean percent difference ranging from 2.3%-5.0%. Lin's Concordance Correlation Coefficients for MR-based vs CT-based measurements ranged from 0.998-1.000. CONCLUSION: The proposed dual-radiofrequency dual-echo 3D ultrashort echo time imaging technique produces high-resolution bone-specific images within a clinically feasible imaging time, leading to clear visualization of craniofacial skeletal structures. Concordance coefficients suggest good reliability of the method compared to CT. The method is currently limited by time and manual input necessary for segmentation correction. Further investigation is needed for more accurate 3D renderings and for scanning of pediatric patients.
RATIONAL AND OBJECTIVES: Computed tomography (CT) is the clinical gold-standard for high-resolution 3D visualization of cortical bone structures. However, ionizing radiation is of concern, particularly for pediatric patients. This study evaluates the feasibility of producing 3D human skull renderings using a novel bone-selective magnetic resonance imaging technique. MATERIALS AND METHODS: A dual-radiofrequency pulse, dual-echo, 3D ultrashort echo time sequence was applied for scanning of a cadaver skull and five healthy adult subjects. Scans were each completed within 6 minutes. Semiautomatic segmentation of bone voxels was performed using ITK-SNAP software, leading to 3D renderings of the skulls. For comparison, thin-slice head CT scans were performed. Mimics software was used to measure eight anatomic distances from 3D renderings. Lin's Concordance Correlation test was applied to assess agreement between measurements from MR-based and CT-based 3D skull renderings. RESULTS: The 3D rendered MR images depict most craniofacial features (e.g., zygomatic arch), although some voxels were erroneously included or excluded in the renderings. MR-based measurements differed from CT-based measurements by mean percent difference ranging from 2.3%-5.0%. Lin's Concordance Correlation Coefficients for MR-based vs CT-based measurements ranged from 0.998-1.000. CONCLUSION: The proposed dual-radiofrequency dual-echo 3D ultrashort echo time imaging technique produces high-resolution bone-specific images within a clinically feasible imaging time, leading to clear visualization of craniofacial skeletal structures. Concordance coefficients suggest good reliability of the method compared to CT. The method is currently limited by time and manual input necessary for segmentation correction. Further investigation is needed for more accurate 3D renderings and for scanning of pediatric patients.
Authors: Carrie E Zimmerman; Pulkit Khandelwal; Long Xie; Hyunyeol Lee; Hee Kwon Song; Paul A Yushkevich; Arastoo Vossough; Scott P Bartlett; Felix W Wehrli Journal: Acad Radiol Date: 2021-04-24 Impact factor: 3.173
Authors: Mateusz C Florkow; Koen Willemsen; Vasco V Mascarenhas; Edwin H G Oei; Marijn van Stralen; Peter R Seevinck Journal: J Magn Reson Imaging Date: 2022-01-19 Impact factor: 5.119