Image Quality and Radiation Dose of Conventional and Wide-Field High-Resolution Cone-Beam Computed Tomography for Cerebral Angiography: A Phantom Study

Abstract

There has been an increase in the use of interventional neuroradiology procedures because of their non-invasiveness compared to surgeries and the improved image quality of fluoroscopy, digital subtraction angiography, and rotational angiography. Although cone-beam computed tomography (CBCT) images are inferior to multi-detector CT images in terms of low-contrast detectability and lower radiation doses, CBCT scans are frequently performed because of their accessibility. This study aimed to evaluate the image quality and radiation dose of two different high-resolution CBCTs (HR CBCT): conventional (C-HR CBCT) and wide-field HR CBCT (W-HR CBCT). The modulation transfer function (MTF), noise power spectrum (NPS), and contrast-to-noise ratio (CNR) were used to evaluate the image quality. On comparing the MTF of C-HR CBCT with a 256 × 256 matrix and that of W-HR CBCT with a 384 × 384 matrix, the MTF of W-HR CBCT with the 384 × 384 matrix was larger. A comparison of the NPS and CNR of C-HR CBCT with a 256 × 256 matrix and W-HR CBCT with a 384 × 384 matrix showed that both values were comparable. The reference air kerma values were equal for C-HR CBCT and W-HR CBCT; however, the value of the kerma area product was 1.44 times higher for W-HR CBCT compared to C-HR CBCT. The W-HR CBCT allowed for improved spatial resolution while maintaining the image noise and low-contrast detectability by changing the number of image matrices from 256 × 256 to 384 × 384. Our study revealed the image characteristics and radiation dose of W-HR CBCT. Given its advantages of low-contrast detectability and wide-area imaging with high spatial resolution, W-HR CBCT may be useful in interventional neuroradiology for acute ischemic stroke.

Evaluation of Radiation Exposure and Influential Factors in Cone-Beam Computed Tomography (CBCT) of the Head and Abdomen during Interventional Procedures

“…In the head CBCT scans, the DAP value in the FOV48 cm group was 1.28 times higher than that in the FOV42 cm group. Similar findings have been reported by Kawauchi et al [ 16 ], who found that the DAP value in their FOV27 cm group was 1.44 times higher than that in their FOV22 cm group. However, it is worth noting that their study showed equal RAK values between the two FOV size groups, differing from our results.…”

“…While previous studies have explored the role of CBCT in interventional procedures [ 3 , 6 , 10 ], there has been limited research specifically focusing on the radiation dose associated with CBCT image acquisition. Some studies have employed phantoms to estimate the dose of CBCT, but the corresponding results have shown significant variations due to the different methodologies used for estimating the effective dose (ED) [ 12 , 13 , 14 , 15 , 16 , 17 ]. Direct measurement of ED may be affected by differences in phantom size or material.…”

“…This result underscores the necessity of further investigation into the clinical doses of CBCT. Although patient characteristics, exposure parameters, and field-of-view (FOV) size have been shown to be possible factors that increase the radiation dose from fluoroscopy and 2D angiography [ 15 , 16 , 18 , 19 , 20 , 21 ], the effects of these factors on the CBCT radiation dose administered to different parts of the body are not well understood due to differences in the modulation of 2D versus 3D imaging parameters by the imaging device. Therefore, there is a need to explore and evaluate the factors affecting CBCT radiation dose and exposure parameters to optimize radiation safety and provide a clinical reference for further research into more dose-efficient imaging protocols.…”