Sains Malaysiana 44(9)(2015): 1331–1337

 

Effect of Different Angle Scanning on Density Estimation Based on Hounsfield Unit on CT and CBCT

(Kesan Imbasan Sudut Berlainan ke atas Anggaran Kepadatan berdasarkan Unit Hounsfield pada CT dan CBCT)

MAYA GENISA1*, ZAINUL AHMAD RAJION1, DASMAWATI MOHAMAD1, ABDULLAH POHCHI1, MOHD RAFIQ ABDUL KADIR2 & SOLEHUDDIN SHUIB3

 

1School of Dental Sciences, Universiti Sains Malaysia, Health Campus, 16150 Kubang Kerian, Kelantan Darul Naim, Malaysia

 

2Faculty of Biomedical Engineering & Health Sciences, Universiti Teknologi Malaysia

81310 Skudai, Johor Darul Takzim, Malaysia

 

3School of Mechanical Engineering, Engineering Campus, Universiti Sains Malaysia

14300 Nibong Tebal, Pulau Pinang, Malaysia

 

Diserahkan: 29 September 2013/Diterima: 25 Mei 2015

 

ABSTRACT

This study aim to evaluate the effect of different angle on bone density estimation based on HU on CT and CBCT scanning. A phantom of jaw was scanned using CT and CBCT machine from different angle (0, 15 and 30 degrees). The data were transformed into DICOM format and loaded into MIMICS software for density measurement. The density was measured at 9.55 mm from cemento-enamel junction (CEJ) on every different angle scanning data. Then these data were grouped as Group A1, A2 and A3 for CBCT group (0, 15 and 30 degrees, respectively) and Group B1, B2 and B3 for CT group (0, 15 and 30 degrees, respectively). The differences between the groups and the references (0 degree scanning) are measured statistically using SPSS software. In the CBCT data, the density reading at 15 and 30 degrees are higher than 0 degree scanning (mean difference = -155.63±62.61, p=0.03, mean difference = -33.13±84.24, p=0.206 for 15 and 30 degrees scanning, respectively). In the CT data, the density at 15 and 30 degrees scanning is lower than at 0 degrees scanning (mean different: 84.49±46.76, p=0.09 and 15.09±23.61, p=0.532). The differences are not significant statistically. Compared with CT, the effect of different angle scanning on density estimation on CBCT is stronger. These results showed that different angle scanning produce more error on density estimation based on HU on CBCT compared with CT. This study demonstrated that the uses of a CBCT and CT for density monitoring to evaluate bone density of jaws are affected by angle scanning.

 

Keywords: Angle scanning; cemento-enamel junction; density; Hounsfield unit

 

ABSTRAK

Matlamat kajian ini adalah untuk menilai kesan sudut berbeza pada anggaran ketumpatan tulang berdasarkan HU pada imbasan CT dan CBCT. Model rahang telah diimbas dengan menggunakan CT dan CBCT daripada sudut berbeza (0, 15 dan 30 darjah). Data diubah kepada format DICOM dan dimuatnaik ke dalam perisian MIMICS untuk pengiraan ketumpatan. Ketumpatan diukur pada 9.55 mm dari temuan simento-enamel (CEJ) di setiap sudut berbeza data imbasan. Data ini kemudiannya dikumpulkan sebagai Kumpulan A1, A2 dan A3 untuk kumpulan CBCT (masing-masing 0, 15 dan 30 darjah) dan Kumpulan B1, B2 dan B3 bagi kumpulan CT (masing-masing 0, 15 dan 30 darjah). Perbezaan antara kumpulan dan rujukan (0 darjah imbasan) diukur secara statistik menggunakan perisian SPSS. Dalam data CBCT, bacaan ketumpatan pada 15 dan 30 darjah adalah lebih tinggi daripada 0 darjah imbasan (min beza = -155,63±62.61, p=0.03, min beza = -133,13±84.24, p=0,206 pada 15 dan 30 darjah imbasan). Dalam data CT, ketumpatan pada 15 dan 30 darjah imbasan adalah lebih rendah daripada 0 darjah imbasan (min beza: 84,49±46.76, p=0.09 dan 15.09±23.61, p=0,532). Perbezaan ini tidak ketara secara statistik. Berbanding dengan CT, kesan imbasan sudut berbeza pada anggaran kepadatan CBCT adalah lebih kuat. Keputusan ini menunjukkan bahawa imbasan sudut berbeza menghasilkan lebih banyak ralat dalam anggaran kepadatan berdasarkan HU pada CBCT berbanding CT. Kajian ini menunjukkan bahawa penggunaan CBCT dan CT untuk memantau ketumpatan dalam menilai ketumpatan tulang rahang dipengaruhi oleh imbasan sudut.

 

Kata kunci: Ketumpatan; sudut imbasan; temuan simento-enamel; unit Hounsfield

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*Pengarang untuk surat-menyurat; email: mgenisa@gmail.com

 

 

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