Movement characteristics in young patients and the impact on CBCT image quality

Abstract

Objectives: To assess patient movement characteristics in children and young adults and the impact on CBCT image quality. Methods: During 33 CBCT examinations, the patients (age: average, 14 years; range, 9-25 years) who had moved were identified by video observation [movement group (MG)]. The CBCT data sets were matched with those of 33 non-moving patients according to age, diagnostic task, examined region, field of view and voxel resolution [non-movement group (N-MG)]. Three observers scored the videos of MG, regarding motional state second by second (moving/non-moving), and movement characteristics: duration (in seconds), complexity (uniplanar or multiplanar) and distance (,3/$3 # 10/.10 mm). The observers blindly assessed axial sections of the 66 examinations individually, categorizing the image quality (appropriate/acceptable/inappropriate). Next, the observers blindly assessed axial sections of the matched-pairs images simultaneously, deciding which image in the pair had the highest image quality or if it was impossible to decide. The relationship between image quality and movement/movement characteristics was evaluated. Results: When the 66 CBCT images were evaluated individually, no relationship between image quality and movement was found. However, based on the matched-pairs assessment, accumulated number (#2 vs $3, p 5 0.039), duration (#5 s vs $6 s, p 5 0.024) and complexity (uniplanar vs multiplanar, p 5 0.046) of movements had an impact on image quality; the more severe the movement, the more often the image quality was assessed lower in the MG. Conclusions: Axial CBCT images of young patients who moved during examination did not always present lower quality than images originating from non-moving patients. Image quality was, however, significantly lower in the moving patients when movement occurred several times, had a long duration or was multiplanar.

Detection of patient movement during CBCT examination using video observation compared with an accelerometer-gyroscope tracking system

“…12 On the other hand, another recent study showed that axial CBCT images of impacted teeth of patients who are young with no metal in the field of view (FOV), who had been observed to move during examination, did not always present a subjectively lower quality than images originating from patients who did not move, when blindly assessed. 13 The same study showed that image quality was lower when patient movement had been observed several times during the examination, were long-lasting (i.e., longer than 5 seconds) or complex (i.e., multiplanar). 13 In any case, if patient motion artefacts are present in an image and compromise image quality, misdiagnosis may occur or a re-exposure of the patient may be decided.…”

“…13 The same study showed that image quality was lower when patient movement had been observed several times during the examination, were long-lasting (i.e., longer than 5 seconds) or complex (i.e., multiplanar). 13 In any case, if patient motion artefacts are present in an image and compromise image quality, misdiagnosis may occur or a re-exposure of the patient may be decided. 11,12 This is a major concern particularly (but not only) when the patient is a child, and 4 being a child is the major factor related to patient movement.…”

“…These videos were later cropped to fit the examination time (in which the CBCT arm containing the X-ray tube moves around the patient), synchronized (to show the exact same period of the examination and to last exactly the same time) and saved as audio video interleaved files, keeping the native resolution and speed. 11,13,14 Patients agreed to be video recorded during CBCT examination. According to Danish regulations, an approval by an ethical committee was not required, since the CBCT examination was requested by the patient clinician and ratified by a radiologist, and the video cameras did not interfere with the examination.…”

“…Patient movement definition by means of video observation As previously reported, 11,13 three observers (radiologists working with CBCT for several years and trained in how to detect patient movement in the videos) assessed the videos of the patients and scored patient movement (yes/no). They assessed the patient videos individually on a 24-inch-flat screen monitor (Dell P2412H; Dell Inc., Round Rock, TX).…”

“…4 Previous studies included the observation of video recordings by trained observers of patients under CBCT examination, suggesting a prevalence of approximately 20% of patients who move. 11,13,14 A drawback of the video camera method may be that movement detection based on watching the videos is to some extent a subjective, operator-dependent method. Further, video recordings provide only a twodimensional picture of a three-dimensional (3D) movement in space, hampering quantitative estimates of patient movement.…”