Sex dependent variations in craniofacial soft-tissue thicknesses estimated from MRI and CT scans: A pilot study based on Northwest Indian subjects

Abstract

Craniofacial identification is a technique for prediction and recreation of life-like appearances of an individual, recreated onto an unknown skull on the basis of intricate relationship existing between underlying bony contour and the overlying soft tissues, muscles and skin. Tissue thicknesses in different population have wide variations due to disparities in nutritional, environmental or genetical factors. The physical health, nutritional status and disease activity of an individual have significant and detectable influences on both the complex anatomy of facial skeleton as well as soft tissue depths. Present study was conducted on 50 MRI and 53 CT normal scans of 64 male and 39 female Northwest Indian adult subjects who reported to radio-imaging diagnostic centres for some clinical and therapeutic reasons. Soft-tissue thickness was estimated at 33 craniofacial landmarks on both MRI and CT scans using OsiriX v 6.0.2 64 bit software and Digital Imaging and Communications in Medicine (DICOM) format images. MRI scans were found comparatively better and more reliable mean of estimating tissue depths and for sex estimations. Statistically significant sex differences were noticed in tissue depths at various craniofacial landmarks. The endocanthion was found the best sex discriminating variable from both types of scans. MRI and CT scan estimated tissue thicknesses could identify sex of 96% and 85%, subjects, respectively. Secular increase in tissue depths was observed to support the increased trend of obesity in present day population of the area when compared with similar studies conducted few decades earlier. Present study results can be a valuable adjunct for forensic anthropological facial reconstructions and experts of diverse medical disciplines.

Application of cone beam computed tomography in facial soft tissue thickness measurements for craniofacial reconstruction

“…In spite of lateral cephalograms clearly demonstrating the profile soft tissue outlines and facilitating midline measurements, the accuracy of 2D radiographic techniques is limited when compared to the advanced imaging owing to technique related errors such as superimposition. On the contrary, the differences between CT[ 30 ] and CBCT (current study) derived values are negligible and statistically insignificant at majority of the landmarks. CBCT provides high-quality images at a lower radiation dose using less expensive equipment.…”

“…To understand whether the choice of technique affects the measurements, the data of the current study were compared with three other Indian studies[ 17 18 30 ] wherein the researchers have used various noninvasive techniques such as lateral cephalogram,[ 17 ] MRI[ 18 ] and CT.[ 30 ] The midline FSTT values of all the four studies differed from one another, the differences being statistically significant between the radiographic study[ 17 ] and all the other three. In spite of lateral cephalograms clearly demonstrating the profile soft tissue outlines and facilitating midline measurements, the accuracy of 2D radiographic techniques is limited when compared to the advanced imaging owing to technique related errors such as superimposition.…”

Male and Female Characteristics of Facial Soft Tissue Thickness in Different Orthodontic Malocclusions Evaluated by Cephalometric Radiography

“…Because it may never be possible to describe and predict all the variations of the male and female human face and the relationship between the bone and soft tissue, the measurement of FSTT has multiple diagnostic, clinical, anthropological, and forensic applications, including craniofacial reconstruction, facial plastic surgery, reconstructive and orthognathic maxillofacial surgery, and evaluation of benign and malignant facial tumors [ 18 ]. Because soft tissues do not form a layer of equal thickness which simply shapes the configuration of basic dental and skeletal structures, the variability of FSTT can reflect the facial profile and should be a factor in diagnosis and the planning of orthodontic treatment [ 10 , 12 ].…”

“…Recent studies have shown that not all areas of the soft tissue profile directly follow skeletal structures and, in some areas the contours of the facial tissue deviate from basic skeletal structures [ 7 , 18 , 34 ]. In everyday orthodontic practice, there are standard cephalometric measurements and analysis done on the basis of cephalometric radiography of facial profiles to determine relationships between contours of a facial skeleton, as well as FSTT measurements [ 4 ].…”

“…Standard values of FSTT and other rules based on anatomy are used for facial reconstruction, but FSTT values are usually used for determining the thickness of tissue that lies on predetermined landmarks of the skull [ 5 ]. Knowing the quantitative distribution of FSTT in different areas is a necessary factor for creating recognizable facial contours on an unknown skull [ 17 , 18 , 22 , 23 ].…”