Comparison of the Diagnostic Image Quality of the Canine Maxillary Dentoalveolar Structures Obtained by Cone Beam Computed Tomography and 64-Multidetector Row Computed Tomography

An application of the density standard and scaled-pixel-counting protocol to assess the radiodensity of equine incisor teeth affected by resorption and hypercementosis: preliminary advancement in dental radiography

BACKGROUND

Equine Odontoclastic Tooth Resorption and Hypercementosis (EOTRH) syndrome is a dental disease where the radiographic signs may be quantified using radiographic texture features. This study aimed to implement the scaled-pixel-counting protocol to quantify and compare the image structure of teeth and the density standard in order to improve the identification of the radiographic signs of tooth resorption and hypercementosis using the EOTRH syndrome model.

METHODS AND RESULTS

A detailed examination of the oral cavity was performed in 80 horses and maxillary incisor teeth were evaluated radiographically, including an assessment of the density standard. On each of the radiographs, pixel brightness (PB) was extracted for each of the ten steps of the density standard (S1-S10). Then, each evaluated incisor tooth was assigned to one of 0-3 EOTRH grade-related groups and annotated using region of interest (ROI). For each ROI, the number of pixels (NP) from each range was calculated. The linear relation between an original X-ray beam attenuation and PB was confirmed for the density standard. The NP values increased with the number of steps of the density standard as well as with EOTRH degrees. Similar accuracy of the EOTRH grade differentiation was noted for data pairs EOTRH 0-3 and EOTRH 0-1, allowing for the differentiation of both late and early radiographic signs of EOTRH.

CONCLUSION

The scaled-pixel-counting protocol based on the use of density standard has been successfully implemented for the differentiation of radiographic signs of EOTRH degrees.

Use of cone-beam computed tomography for advanced imaging of the equine patient

Access to volumetric imaging modalities, such as magnetic resonance imaging (MRI) and computed tomography (CT), has increased over the past decade and has revolutionised the way clinicians evaluate equine anatomy. More recent advancements have resulted in the development of multiple commercially available cone-beam CT (CBCT) scanners for equine use. CBCT scanners modify the traditional fan-shaped beam of ionising radiation into a three-dimensional pyramidal- or cone-shaped beam of radiation. This modification enables the scanner to acquire sufficient data to create diagnostic images of a region of interest after a single rotation of the gantry. The rapid acquisition of data and divergent X-ray beam causes some artifacts to be more prominent on CBCT images-as well as the unique cone-beam artifact-resulting in decreased contrast resolution. While the use of CT for evaluation of the equine musculoskeletal anatomy is not new, there is a paucity of literature and scientific studies on the capabilities of CBCT for equine imaging. CBCT units do not require a specialised table for imaging and in some cases are portable for imaging in the standing or anaesthetised patient. This review article summarises the basic physics of CT technology, including how CBCT imaging differs, and provides objective information about the strengths and limitations of this modality. Finally, potential future applications and techniques for imaging with CT which will need to be explored in order to fully consider the capabilities of CT imaging in the horse are discussed.

Multidetector CT and cone-beam CT have substantial agreement in detecting dental and sinus abnormalities in equine cadaver heads

The performance of cone-beam CT (CBCT) systems compared to conventional helical multidetector CT (MDCT) imaging of the equine head is unknown. The aim of this prospective, method-comparison study was to compare the ability of CBCT and MDCT to detect abnormalities in equine cadaver heads. Eleven equine cadaver heads were scanned using a CBCT scanner and a 64-slice MDCT scanner. Consensus evaluations for CBCT and MDCT scans were performed by three observers. Identified abnormalities were grouped into subcategories with a focus on dental abnormalities. Kappa agreement values between detected abnormalities for CBCT and MDCT methods were calculated. Of 468 teeth evaluated, 122 (26.1%) were found to have abnormalities (including in 58 infundibula and 7 pulps) using MDCT and 105 (22.4%) were found to have abnormalities (including in 52 infundibula and 2 pulps) using CBCT. The agreement between CBCT and MDCT was almost perfect for overall detection of dental abnormalities (k = 0.90) with k = 1 for diastema k = 0.95 for clinical crown abnormalities, and k = 0.93 for infundibular abnormalities. However, the detection of pulp changes by CBCT was only moderate k = 0.44. Increased scatter radiation, non-calibrated Hounsfield Unit and artefacts in CBCT images made accurate identification of the pulp density difficult. In conclusion, CBCT results were similar to conventional MDCT for the majority of dental abnormalities, however, pulp abnormalities were not reliably identified using CBCT, potentially limiting its clinical use for detecting endodontic disease in its current form. Further comparison with more cases with confirmed dental disease and studies in clinical cases are warranted.

Localization of the First Mandibular Molar Roots in Relationship to the Mandibular Canal in Small Breed Dogs-A Tomography Imaging Study

The intimate relationship between the mandibular canal (MC) and the first mandibular molar tooth presents challenges when performing dentoalveolar surgical procedures due to the probability of causing iatrogenic injury to the inferior alveolar neurovascular bundle. Superimposition between the MC and the first molar (M1) tooth roots is often observed on intraoral dental radiographs in small breed dogs. However, due to the radiograph's bidimensional nature, it is impossible to determine the buccal or lingual localization of the first molar roots with respect to the MC. Thus, this study's objective was to determine the localization of the first molar tooth's roots in relation to the position of the MC and their overlapping percentage with the canal in small-bodyweight dogs (<15 kg) using tomographic diagnostic images. For this, cone-beam computed tomography and high-definition computed tomography exams from 103 small breed dogs (under 15 kg) were retrospectively assessed to determine the lingual or buccal localization of the first molar tooth's roots with respect to the MC and the degree of overlap of the roots with the canal. In conclusion, most of the roots of M1 of dogs under 15 kg were located at the MC's lingual aspect (82.7%) with an overall superimposition median with the MC of 100 and 90% for the mesial and distal roots, respectively. Straddle tooth roots were not a common anatomical presentation in the dogs of this study.

Patterns of local residual disease and local failure after intensity modulated/image guided radiation therapy for sinonasal tumors in dogs

BACKGROUND

Most dogs with sinonasal tumors (SNT) treated with radiation therapy (RT) died because of local disease progression.

HYPOTHESIS/OBJECTIVES

Our hypothesis is that the majority of local failure and residual disease would occur within the radiation field.

ANIMALS

Twenty-two dogs with SNT treated with RT.

METHODS

Retrospective cohort study.

INCLUSION CRITERIA

dogs with SNT receiving 10 daily fractions of 4.2 Gy with intensity modulated radiation therapy (IMRT)/image guided radiation therapy (IGRT) and follow-up cone beam computed tomography (CBCT). Each CBCT was registered with the original radiation planning CT and the gross tumor volume (GTV) contoured. The GTV was classified as residual (GTVr) or a failure (GTVf). The dose statistic for each GTV was calculated with the original IMRT plan. For GTVf, failures were classified as "in-field," "marginal," or "out-field" if at least 95, 20-95, or less than 20% of the volume of failure was within 95% (D95) of the total prescription dose, respectively.

RESULTS

There were 52 follow-up CBCT/CTs. Overall there was a GTVr for 20 dogs and GTVf for 16 dogs. The majority of GTVr volume was within the original GTV. GTVf analysis showed that 75% (12/16) were "in-field," 19% (3/16) were "marginal" and 6% (1/16) were "out-field."

CONCLUSION AND CLINICAL IMPORTANCE

In-field failures are the main pattern for local recurrence, and there is evidence of radioresistant subvolumes within the GTV.

Validation of standing cone beam computed tomography for diagnosing subchondral fetlock pathology in the Thoroughbred racehorse

BACKGROUND

Subchondral bone pathology is common in Thoroughbred racehorses and believed to precede more serious injury. Early identification of pathology is critical to allow for intervention.

OBJECTIVES

To determine interobserver variability of fetlock subchondral bone lesions using cone beam and fan beam computed tomography (CBCT, FBCT) and to validate a robotics-controlled CBCT to identify fetlock subchondral bone pathology in the Thoroughbred racehorse.

STUDY DESIGN

Prospective cohort study.

METHODS

FBCT and CBCT images were acquired of 25 metacarpo-/metatarsophalangeal joints of Thoroughbred racehorses. Images were analysed for subchondral bone lesions commonly identified in Thoroughbred fetlocks by an imaging specialist and surgery specialist. Interobserver and intermodality equivalence were determined with a Pearson correlation analysis and Bland-Altman equivalence test.

RESULTS

Interobserver FBCT correlation was significant (P < .05) for 19 of 25 variables (Pearson R mean 0.77). Concordance was significant for all 25 variables (Bland Altman average difference 0.28 ± 0.21 mm). Interobserver CBCT correlation was significant for 21 of 25 variables (Pearson R mean 0.73). Concordance was significant for all variables (Bland Altman average difference 0.07 ± 1.90 mm). Intermodality (FBCT vs CBCT) correlation and concordance was significant for all variables as interpreted by the radiologist (Pearson R mean of 0.72, Bland Altman average difference 0.21 ± 0.47 mm). Intermodality correlation was significant for 19 of 25 variables as interpreted by the surgeon (Pearson R mean of 0.72). Concordance was significant for all variables (Bland Altman average difference 0.49 ± 0.52 mm).

MAIN LIMITATIONS

Neither FBCT nor CBCT images were compared with other imaging modalities/histopathology; limited number of cases included; inconsistent agreement of small lesions in specific categories.

CONCLUSIONS

Standing CBCT is a valid diagnostic modality to identify subchondral bone lesions in Thoroughbred fetlocks. This technology may provide valuable information regarding the development and progression of fetlock pathology and yield insight into predisposing factors leading to more severe pathology.

Comparison of dental radiography and computed tomography: measurement of dentoalveolar structures in healthy, small-sized dogs and cats

BACKGROUND

Dental diseases are common in dogs and cats, and accurate measurements of dentoalveolar structure are important for planning of treatment. The information that the comparison computed tomography (CT) with dental radiography (DTR) is not yet reported in veterinary medicine.

OBJECTIVES

The purpose of this study was to compare the DTR with CT of dentoalveolar structures in healthy dogs and cats, and to evaluate the CT images of 2 different slice thicknesses (0.5 and 1.0 mm).

METHODS

We included 6 dogs (2 Maltese and 1 Spitz, Beagle, Pomeranian, mixed, 1 to 8 years, 4 castrated males, and 2 spayed female) and 6 cats (6 domestic short hair,8 months to 3 years, 4 castrated male and 2 spayed female) in this study. We measured the pulp cavity to tooth width ratio (P/T ratio) and periodontal space of maxillary and mandibular canine teeth, maxillary fourth premolar, mandibular first molar, maxillary third premolar and mandibular fourth premolar.

RESULTS

P/T ratio and periodontal space in the overall dentition of both dogs and cats were smaller in DTR compared to CT. In addition, CT images at 1.0 mm slice thickness was generally measured to be greater than the images at 0.5 mm slice thickness.

CONCLUSIONS

The results indicate that CT with thin slice thickness provides more accurate information on the dentoalveolar structures. Additional DTR, therefore, may not be required for evaluating dental structure in small-sized dogs and cats.

World Small Animal Veterinary Association Global Dental Guidelines

Dental, oral, and maxillofacial diseases are some of the most common problems in small animal veterinary practice. These conditions create significant pain as well as localized and potentially systemic infection. As such, the World Small Animal Veterinary Association (WSAVA) believes that un- and under treated oral and dental diseases pose a significant animal welfare concern. Dentistry is an area of veterinary medicine which is still widely ignored and is subject to many myths and misconceptions. Effective teaching of veterinary dentistry in the veterinary school is the key to progression in this field of veterinary medicine, and to the improvement of welfare for all our patients globally. These guidelines were developed to provide veterinarians with the information required to understand best practices for dental therapy and create realistic minimum standards of care. Using the three-tiered continuing education system of WSAVA, the guidelines make global equipment and therapeutic recommendations and highlight the anaesthetic and welfare requirements for small animal patients. This document contains information on common oral and dental pathologies, diagnostic procedures (an easily implementable and repeatable scoring system for dental health, dental radiography and radiology) and treatments (periodontal therapy, extractions). Further, there are sections on anaesthesia and pain management for dental procedures, home dental care, nutritional information, and recommendations on the role of the universities in improving veterinary dentistry. A discussion of the deleterious effects of anaesthesia free dentistry (AFD) is included, as this procedure is ineffective at best and damaging at worst. Throughout the document the negative effects of undiagnosed and/or treated dental disease on the health and well-being of our patients, and how this equates to an animal welfare issue, is discussed.

Qualitative and Quantitative Assessment of Alveolar Bone Destruction in Adult Rats Using CBCT

Cone-beam computed tomography (CBCT) has strong potential to be utilized in various aspects of veterinary dentistry. Using ex vivo rat maxillary bone and teeth, the purpose of this study was to compare gray value, surface area, and volumetric measurements of teeth with and without experimental periodontitis by CBCT. Periodontitis was induced in 36 molar teeth, while 36 teeth with a healthy periodontium served as control. Images of each specimen along with teeth were obtained using CBCT. The following measurements for each tooth with periodontitis (n = 36) were recorded: gray value measurement, width, height, depth, surface area, and volume of the alveolar bone loss. For the control group (n = 36), gray value measurement, surface area, and volume of the alveolar bone were recorded. All measurements were repeated after 3 weeks. As the gold standard, the rat maxillas were decalcified and paraffin-embedded for further immunocytochemical study. One-way analysis of variance (ANOVA) was used. Significance level was set at P < .05. Correlation values for gray value, width, height, depth, surface area, and volume measurements were 0.983, 0.966, 0.962, 0.880, 0.998, and 0.999, respectively, for the first and second measurements. One way ANOVA showed statistically significant differences between teeth with and without alveolar bone destruction conducted for gray value, surface area, and volume measurements (P = .000). Mean gray value, surface area, and volume measurements decreased 56.46%, 81.89%, and 78.56%, respectively, for teeth with alveolar bone destruction in comparison to healthy teeth. Cone-beam computed tomography provided useful qualitative and quantitative information regarding induced periodontitis in the rat maxilla.

Analysis of the Anatomic Relationship Between the Mandibular First Molar Roots and Mandibular Canal Using Cone-Beam Computed-Tomography in 101 Dogs

The mandibular first molar (M1) tooth of the dog is commonly involved in dental procedures. Tooth roots and the mandibular canal can vary in location, which has not been described on a large scale. The objective of this study was to describe the three-dimensional anatomic relationship of the mandibular M1 tooth roots and the mandibular canal in dogs. Cone-beam computed tomography (CBCT) was used to evaluate the anatomic relationship between the M1 tooth roots and the mandibular canal. CBCT images were collected from 101 canine cadaver heads from a variety of unknown breeds. All skulls used in this study were mesaticephalic, confirmed by facial index calculations. The position of the apex in relation to the mandibular canal and in relation to the buccal and lingual cortices was recorded and analyzed in relation to mandibular bone height: root length ratio. When evaluating the apex in a buccal-lingual relationship, the tooth roots were found to be located closer to the lingual cortex in 73.3% of M1 roots. Tooth root apical positions were found to be symmetric between the right and left side of the mouth in 93% of mesial roots and 95% of distal roots. Apical positions relative to the mandibular canal within the same tooth were found to be consistent in 52% of teeth. Teeth with roots dorsal to the mandibular canal were associated with the largest mandibular bone height: root length ratio. CBCT provides a more precise overview than dental radiographs of three-dimensional anatomy. The tooth root position can be estimated in a clinical setting based on the ratio of mandibular bone height to tooth root length obtained from intraoral radiographs. Understanding the relative location of important anatomic structures is key to avoiding complications associated with various dental procedures. This study has documented that assessing anatomic structures with 2D imaging alone is flawed, and the large majority of dogs have M1 roots closer to the lingual aspect than the buccal aspect of the mandible.

Diagnosis and Treatment of an Odontogenic Epithelial Tumor in a Dog With Features of Squamous Odontogenic Tumor

A 9-year-old standard poodle presented for a comprehensive oral health assessment and treatment, at which time a left rostral mandibular swelling was recognized. The mass was biopsied and eventually excised by a left rostral mandibulectomy en bloc resection. Histopathology supported the diagnosis of a benign, intraosseous, epithelial tumor that was otherwise unclassified. The clinical, radiological, and histological features of this case are similar to those reported for squamous odontogenic tumor (SOT) in humans. This case study relays the diagnosis, treatment, and follow-up of the first SOT-like tumor in a dog.

Diagnostic Yield of Dental Radiography and Cone-Beam Computed Tomography for the Identification of Anatomic Structures in Cats

The objective of this study was to evaluate the diagnostic yield of dental radiography (DR) and 3 cone-beam computed tomography (CBCT) methods for the identification of predefined anatomic structures in cats. For 5 feline cadaver heads and 22 client-owned cats admitted for evaluation and treatment of dental disease, a total of 22 predefined anatomic structures were evaluated separately by use of the DR method and 3 CBCT software modules [multiplanar reconstructions (MPR), tridimensional (3-D) rendering, and reconstructed panoramic views (Pano)]. A semi quantitative scoring system was used, and mean scores were calculated for each anatomic structure and imaging method. The Friedman test was used to evaluate values for significant differences in diagnostic yield. For values that were significant the Wilcoxon signed rank test was used with the Bonferroni-Holm multiple comparison adjustment to determine significant differences among each of the possible pairs of diagnostic methods. Differences of diagnostic yield among the DR and 3 CBCT methods were significant for 17 of 22 anatomic structures. For these structures, DR scores were significantly higher than scores for Pano views for 2 of 17 structures, but DR scores were significantly lower than scores for Pano views for 6 anatomic structures, tridimensional rendering for 10 anatomic structures, and MPR for 17 anatomic structures. In conclusion, it was found that CBCT methods were better suited than DR for the identification of anatomic structures in cats. Results of this study can serve as a basis for CBCT evaluation of dentoalveolar and other maxillofacial bony lesions in cats.

The Diagnostic Yield of Dental Radiography and Cone-Beam Computed Tomography for the Identification of Dentoalveolar Lesions in Cats

The objective of this study was to evaluate the diagnostic yield of dental radiography (DR) and 3 cone-beam computed tomography (CBCT) software modules for the identification of 32 pre-defined dentoalveolar lesions in cats. For 5 feline cadaver heads and 22 client-owned cats admitted for evaluation and treatment of dental disease, 32 predefined dentoalveolar lesions were evaluated separately and scored by use of dental radiography and 3 CBCT software modules [multiplanar reconstructions (MPR), tridimensional (3-D) rendering, and reconstructed panoramic views]. A qualitative scoring system was used. Dentoalveolar lesions were grouped into 14 categories for statistical analysis. Point of reference for presence or absence of a dentoalveolar lesion was determined as the method that could be used to clearly identify the disorder as being present. Accuracy, sensitivity, specificity, and positive and negative predictive values were calculated with the McNemar χ2 test of marginal homogeneity of paired data. When all 3 CBCT software modules were used in combination, the diagnostic yield of CBCT was significantly higher than that of dental radiography for 4 of 14 categories (missing teeth, horizontal bone loss, loss of tooth integrity, feline resorptive lesions), and higher, although not significantly so, for 9 categories (supernumerary teeth, supernumerary roots, abnormally shaped roots, vertical bone loss, buccal bone expansion, periapical disease, inflammatory root resorption, and external replacement root resorption). In conclusion, we found that CBCT provided more clinically relevant detailed information as compared to dental radiography. Therefore, CBCT should be considered better suited for use in diagnosing dentoalveolar lesions in cats.

Role of Computed Tomography Scan in Dental Trauma: A Cross-Sectional Study

Background:

Dental trauma is caused by fracture(s) in the vertical plane and the horizontal plane of roots. The objective of this study is to perform multiple diagnostic modalities for the diagnosis of horizontal root fracture(s) of the tooth.

Methods:

A total of 250 patients with dental complaints were subjected to intraoral radiography, multidetector helical computed tomography (MDHCT), and limited cone beam computed tomography (LCBCT). The suspected tooth was extracted, visually inspected, and subjected to microcomputed tomography (micro-CT). Images were observed in the lightbox, and a fracture was considered if it had been directly visualized as radiolucent line traversing tooth root. Wilcoxon test/Tukey post hoc test was performed at 99% of confidence level.

Results:

With respect to visual inspection, for LCBCT, intraoral radiography, MDHCT, and micro-CT, sensitivities were 0.988, 0.972, 0.967, and 0.979; accuracies were 0.956, 0.785, 0.905, and 0.888; false-positive values were 5, 21, 12, and 11; and false-negative values were 3, 24, 3, and 11, respectively. The area of the image visible at one time was in the order of treatment without radiography < intraoral radiography < MDHCT < micro-CT < LCBCT.

Conclusion:

The LCBCT had the highest sensitivity and accuracy for diagnosis of horizontal tooth root fracture(s).

Level of Evidence:

I.

Trial Registry:

researchregistry3647, dated December 31, 2016 (www.researchregistry.com).

Comparing Intraoral Radiography and Computed Tomography for Detecting Radiographic Signs of Periodontitis and Endodontic Disease in Dogs: An Agreement Study

OBJECTIVE

To determine whether computed tomography (CT) and intraoral radiography are interchangeable for detecting signs of periodontitis and endodontic disease in dogs.

MATERIALS AND METHODS

An agreement study was performed using 40 dogs that previously underwent intraoral radiography and CT during the same anesthetic episode. Images of each tooth were examined by two blinded observers for signs of periodontitis and/or endodontic disease. Agreement between imaging modalities and between observers was assessed using the Kappa statistic.

RESULTS

Agreement between modalities for detecting periodontitis in the maxillae ranged from poor to very good (κ 0.07-1.00) with 16/20 (80%) of the teeth having a score of moderate or better (κ ≥ 0.41). Agreement between modalities for detecting signs consistent with periodontitis in the mandibles ranged from poor to very good (κ 0.01-1.00) with 10/22 (45%) of the teeth having a score of good or better (κ ≥ 0.61); 50% of the disagreement was present in the incisors. Agreement between modalities for detecting signs consistent with endodontic disease in the whole mouth ranged from fair to very good (κ 0.21-1.00) with 30/42 (71%) of the teeth having a score of moderate or better (κ ≥ 0.41). Agreement between observers evaluating intraoral radiology ranged from poor to very good (κ 0.05-1) for detecting signs consistent with periodontitis and from fair to very good (κ 0.36-1) for detecting signs consistent with endodontic disease, in the whole mouth. Agreement between observers evaluating CT ranged from fair to very good (κ 0.35-1) for detecting signs consistent with periodontitis and from fair to very good (κ 0.36-1) for detecting signs consistent with endodontic disease, in the whole mouth.

CONCLUSION

Performing both CT and intraoral radiography may be unnecessary to detect signs consistent with periodontitis and endodontic disease in dogs based on the amount of agreement between modalities and observers when CT images are acquired and reconstructed in 0.5 or 1 mm slice thickness, except for diagnosing periodontitis in the mandibular incisors.