CT of the medial clavicular epiphysis for forensic age estimation: hands up?

Abstract

Purpose The aim of this study was to assess the impact of arm position in computed tomography (CT) of the clavicle performed for forensic age estimation on clavicular position, image noise, and radiation dose. Methods and materials Forty-seven CT scans of the medial clavicular epiphysis performed for forensic age estimation were conducted with either hands and arms held upwards (CTHU, 28 persons) or positioned at the body (CTHD, 19 persons). Presets were identical for both positions (70 mAs/140 kVp; Brilliance iCT, Philips). Each CT scan was reconstructed with an iterative algorithm (i-Dose 4) and evaluated at the middle of the sternoclavicular joint. Clavicular angle was measured on a.p. topograms in relation to a horizontal line. Quantitative image noise was measured in air at the level of medial clavicular epiphysis. Effective dose and scan length were recorded. Results Hands-up position compared with hands-down position resulted in a lower lateral body diameter (CTHU 41.1 ± 3.6 cm vs. CTHD 44.6 ± 3.1 cm; P = 0.03), a reduced quantitative image noise (CTHU: 39.5 ± 9.2; CTHD: 46.2 ± 8.3; P = 0.02), and lower CTDIvol (5.1 ± 1.4 mGy vs. 6.7 ± 1.8 mGy; P = 0.001). Scan length was longer in patients examined with hands up (HU: 8.5 ± 3.4 cm; HD: 6.2 ± 2.1 cm; P = 0.006). Mean effective dose for CTHU was 0.79 ± 0.32 mSv compared with 0.95 ± 0.38 mSv in CTHD (P = 0.12). Clavicular angle was 17° ± 6° in patients with hands down and 32° ± 7° in patients with hands up (P < 0.001). Conclusion By elevated arm positioning, the image quality of clavicular CT scans can be improved while maintaining radiation dose compared with hands down. Clavicular position differs according to the hand position. Thus, positioning patients with elevated hands is advisable for forensic clavicular CT examinations, but multiplanar CT reconstructions should be adjusted to clavicular position and scan length should be reduced to a minimum.

Standards of practice in forensic age estimation with CT of the medial clavicular epiphysis—a systematic review

“…After elimination of duplicates, the remaining 802 articles were screened and 56 were included for full-text analysis. Of these, 48 studies were included in the systematic review [ 7 , 8 , 10 – 16 , 19 , 20 , 24 – 60 ].

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“…Only 5/48 studies report dose parameters [ 11 , 15 , 16 , 24 , 29 ]. Of these, 3 studies report complete dose information (CTDI, DLP, and effective dose [mSv]) [ 15 , 16 , 24 ], while 2 studies report partial dose information (CTDI and effective dose, respectively) [ 11 , 29 ]. 12/48 provided no information regarding the CT scan parameters and radiation dose.…”

“…The AGFAD recommends using the Schmeling and Kellinghaus classification systems to evaluate the main stage and sub-stage of MCE ossification on CT scans, and advises that two experts should provide age estimates using mutliplanar reformatted (MPR) axial and coronal images with a slice thickness of 1 mm or less and CT window settings optimized for bone viewing [ 6 – 16 ].…”

“…Therefore, radiation protection is a crucial aspect of CT imaging, particularly in the context of FAE where CT is performed for non-medical reasons on a young population, and limiting the scan length to the recommended 4 cm [ 3 , 9 , 11 , 20 – 22 ]) is one way to reduce radiation exposure in FAE [ 9 , 16 , 23 , 24 ]. According to the literature, the effective dose values for CT of the MCE, as estimated and calculated, tend to be low, typically below 1 millisievert (mSv), but can vary from 0.2 to 4.6 mSv depending on the scan protocol [ 11 , 15 , 16 , 21 , 22 , 24 ]. There are currently no established dose reference values and no generally accepted scan settings for CT of the MCE for FAE [ 15 , 16 ].…”

“…According to the literature, the effective dose values for CT of the MCE, as estimated and calculated, tend to be low, typically below 1 millisievert (mSv), but can vary from 0.2 to 4.6 mSv depending on the scan protocol [ 11 , 15 , 16 , 21 , 22 , 24 ]. There are currently no established dose reference values and no generally accepted scan settings for CT of the MCE for FAE [ 15 , 16 ].…”