Spatial resolution in CBCT machines for dental/maxillofacial applications—what do we know today?

Brüllmann, Dan; Schulze, Ralf

doi:10.1259/dmfr.20140204

Cited by 171 publications

(154 citation statements)

References 50 publications

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“…21 The measured limiting spatial resolution did not correlate with reconstructed voxel size, which is consistent with the measurements of Pauwels et al 22 and Bamba et al 15 The images are resampled for display purposes at the voxel spacing reported in the acquisition parameters. Although a general consistency was observed between limiting spatial resolution measured by the 10% MTF and visual inspection of the bar patterns, it is clear that the reported voxel size (reconstructed voxel size) provides only a crude prediction of the spatial accuracy.…”

Section: Discussionsupporting

confidence: 80%

Quantitative performance characterization of image quality and radiation dose for a CS 9300 dental cone beam computed tomography machine

2015

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Abstract. This paper aims to characterize the radiation dose and image quality (IQ) performance of a dental cone beam computed tomography (CBCT) unit over a range of fields of view (FOV). IQ and dose were measured using a Carestream 9300 dental CBCT. Phantoms were positioned in the FOV to imitate clinical positioning. IQ was assessed by scanning a SEDENTEXCT IQ phantom, and images were analyzed in ImageJ. Dose index 1 was obtained using a thimble ionization chamber and SEDENTEXCT DI phantom. Mean gray values agreed within 93.5% to 99.7% across the images, with pixel-to-pixel fluctuations of 6% to 12.5%, with poorer uniformity and increased noise for child protocols. CNR was fairly constant across FOVs, with higher CNR for larger patient settings. The measured limiting spatial resolution agreed well with 10% MTF and bar pattern measurements. Dose was reduced for smaller patient settings within a given FOV; however, smaller FOVs obtained with different acquisition settings did not necessarily result in reduced dose. The use of patient-specific acquisition settings decreased the radiation dose for smaller patients, with minimal impact on the IQ. The full set of IQ and dose measurements is reported to allow dental professionals to compare the different FOV settings for clinical use.

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Section: Discussionsupporting

confidence: 80%

Quantitative performance characterization of image quality and radiation dose for a CS 9300 dental cone beam computed tomography machine

2015

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“…13 Patients cannot remain perfectly still during the full examination time owing to heart beat, breathing and unintentional movements. 8,9,17 It is obvious that clinicians should attempt to reduce the incidence of patent motion artefacts by using "best clinical practice techniques" to reduce/avoid patient movement during CBCT examination. 9 Therefore, attention should be paid to patient positioning, stabilization, instruction and monitoring methods.…”

Section: Discussionmentioning

confidence: 99%

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

Spin‐Neto

Matzen

Schropp

et al. 2017

Dentomaxillofacial Radiology

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Objectives: To compare video observation (VO) with a novel three-dimensional registration method, based on an accelerometer-gyroscope (AG) system, to detect patient movement during CBCT examination. The movements were further analyzed according to complexity and patient age. Methods: In 181 patients (118 females/63 males; age average 30 years, range: 9-84 years), 206 CBCT examinations were performed, which were video-recorded during examination. An AG was, at the same time, attached to the patient head to track head position in three dimensions. Three observers scored patient movement (yes/no) by VO. AG provided movement data on the x-, y-and z-axes. Thresholds for AG-based registration were defined at 0.5, 1, 2, 3 and 4 mm (movement distance). Movement detected by VO was compared with that registered by AG, according to movement complexity (uniplanar vs multiplanar, as defined by AG) and patient age (#15, 16-30 and $31 years). Results: According to AG, movement $0.5 mm was present in 160 (77.7%) examinations. According to VO, movement was present in 46 (22.3%) examinations. One VO-detected movement was not registered by AG. Overall, VO did not detect 71.9% of the movements registered by AG at the 0.5-mm threshold. At a movement distance $4 mm, 20% of the AGregistered movements were not detected by VO. Multiplanar movements such as lateral head rotation (72.1%) and nodding/swallowing (52.6%) were more often detected by VO in comparison with uniplanar movements, such as head lifting (33.6%) and anteroposterior translation (35.6%), at the 0.5-mm threshold. The prevalence of patients who move was highest in patients younger than 16 years (64.3% for VO and 92.3% for AG-based registration at the 0.5-mm threshold). Conclusions: AG-based movement registration resulted in a higher prevalence of patient movement during CBCT examination than VO-based registration. Also, AG-registered multiplanar movements were more frequently detected by VO than uniplanar movements. The prevalence of patients who move was highest in patients younger than 16 years.

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“…These studies reported that between 4.5% and 41.5% of CBCT examinations show artefacts suggestive of patient movement. 13,14,16 But, although some studies 7,8 report on the possible impact of motion artefacts on image quality, knowledge of which types and magnitudes of movements may considerably hamper the diagnostic outcome of a CBCT examination is still a key question. 8 Moreover, it is unclear whether observed artefacts in some studies 13,14,16 were in fact due to patient motion.…”

Section: Discussionmentioning

confidence: 99%

“…beam hardening and extinction artefacts related to metal), 7,8 the study considered only images of young patients with no metal inside the FOV, which relate to the majority of the child populations in Western countries. To provide a strong control group for image quality evaluation, the CBCT images of the moving patients were matched to those of non-moving patients according to age, diagnostic task, examined region, FOV and resolution.…”

Section: Discussionmentioning

confidence: 99%

“…patient-related factors. 7,8 Related to the patient there are motion artefacts, which are speculated to be connected to the relatively long image acquisition time in CBCT. [9][10][11][12] According to the literature, patient motion artefacts in CBCT imaging appear mainly as stripe-and ring-like patterns, double bony contours and overall unsharpness.…”

Section: Introductionmentioning

confidence: 99%

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

Spin‐Neto¹,

Matzen²,

Schropp³

et al. 2016

Dentomaxillofacial Radiology

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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.

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Spatial resolution in CBCT machines for dental/maxillofacial applications—what do we know today?

Cited by 171 publications

References 50 publications

Quantitative performance characterization of image quality and radiation dose for a CS 9300 dental cone beam computed tomography machine

Quantitative performance characterization of image quality and radiation dose for a CS 9300 dental cone beam computed tomography machine

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

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

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