Applying synthetic radiography to intraoral tomosynthesis: a step towards achieving 3D imaging in the dental clinic.

OBJECTIVES: A practical approach to three-dimensional (3D) intraoral imaging would have many potential applications in clinical dentistry. Stationary intraoral tomosynthesis (sIOT) is an experimental 3D imaging technology that holds promise. The purpose of this study was to explore synthetic radiography as a tool to improve the clinical utility of the images generated by an sIOT scan. METHODS: Extracted tooth specimens containing either caries adjacent to restorations (CAR) or vertical root fractures (VRF) were imaged by sIOT and standard dental radiography devices. Qualitative assessments were used to compare the conspicuity of these pathologies in the standard radiographs and in a set of multi-view synthetic radiographs generated from the information collected by sIOT. RESULTS: The sIOT-based synthetic 2D radiographs contained less artefact than the image slices in the reconstructed 3D stack, which is the conventional approach to displaying information from a tomosynthesis scan. As a single sIOT scan can be used to generate synthetic radiographs from multiple viewing angles, the interproximal space was less likely to be obscured in the synthetic images compared to the standard radiograph. Additionally, the multi-view synthetic radiographs can potentially improve the display of CAR and VRFs as compared to a single standard radiograph. CONCLUSIONS: This preliminary experience combining synthetic radiography and sIOT in extracted tooth models is encouraging and supports the ongoing study of this promising approach to 3D intraoral imaging with many potential applications.

Bitewing radiography dosimetry of a stationary intraoral tomosynthesis imaging system.

OBJECTIVES: This study assessed effective doses (E) from conventional and stationary intraoral tomosynthesis (s-IOT) radiography for posterior bitewing (PBW) examinations and evaluated the effect of sensor attenuation. STUDY DESIGN: An adult human tissue-equivalent phantom and optically stimulated luminescent dosimeters were used. Series of 4 PBW radiographs were acquired with circular and rectangular collimation. s-IOT PBW radiographs were acquired with built-in rectangular collimation. Radiographs were acquired without and with a sensor in the beam path. RESULTS: E (in µSv) was 15.7 and 8.2 for conventional-circular, 4.6 and 1.1 for conventional-rectangular, and 11.9 and 5.9 for s-IOT in sensor-absent and sensor-present scenarios, respectively. For sensor-absent exposures, E for conventional-rectangular was 29.3% and E for s-IOT was 75.8% of the conventional-circular dose. With the sensor present, these values were 13.4% and 72.0%, respectively (P < .001). Sensor-present E was lower than sensor-absent E for all modalities (P < .001). Reductions in equivalent doses were similar to effective dose reductions. CONCLUSIONS: For PBW examinations, E for s-IOT was smaller than for conventional radiography with circular collimation, but larger than for conventional radiography with rectangular collimation. The presence of a sensor maintained these differences but reduced E for all modalities.

The role of stationary intraoral tomosynthesis in reducing proximal overlap in bitewing radiography.

OBJECTIVES: This study examined the utility of stationary intraoral tomosynthesis (s-IOT) in opening proximal contacts in bitewing radiography. METHODS: 11 DENTSPLY Rinn Dental X-ray Teaching and Training Replica mannequins (Model #546002, Elgin, Ill) were imaged with a prototype s-IOT device (Surround Medical Systems, Morrisville, NC) and standard bitewing (SBW) technique. Premolar and molar bitewings were acquired with each system. Image receptor holders were used to position receptors and aid in the alignment of the position indicating devices. An expert operator (having more than 5 years of experience in intraoral radiography) acquired the images with the s-IOT prototype and standard intraoral X-ray devices. Images were assessed to analyze percentage overlap of the proximal surfaces using the tools available in ImageJ (NIH, Bethesda Maryland). RESULTS: 253-paired surfaces were included in the analysis. The difference in overlap was statistically significant with standard bitewing (SBW) images resulting in a median overlap of 13%, a minimum of 0%, a maximum of 100% and an interquartile range of 40%. s-IOT resulted in a median overlap of 1%, a minimum of 0%, a maximum of 37% and an interquartile range of 0%. The s-IOT prototype substantially reduced proximal surface overlap compared to conventional bitewing radiography. CONCLUSIONS: The use of s-IOT reduced proximal contact overlap compared to standard bitewing radiography for an experienced radiographer. Stationary intraoral tomosynthesis may be a potential alternative to SBW radiography, reducing the number of retakes due to closed contacts.

Characterization and preliminary imaging evaluation of a clinical prototype stationary intraoral tomosynthesis system.

PURPOSE: Technological advancements in dental radiography have improved oral care on many fronts, yet diagnostic efficacy for some of the most common oral conditions, such as caries, dental cracks and fractures, and periodontal disease, remains relatively low. Driven by the clinical need for a better diagnostic yield for these and other dental conditions, we initiated the development of a stationary intraoral tomosynthesis (s-IOT) imaging system using carbon nanotube (CNT) x-ray source array technology. Here, we report the system characterization and preliminary imaging evaluation of a clinical prototype s-IOT system approved for human use. METHODS: The clinical prototype s-IOT system is comprised of a multibeam CNT x-ray source array, high voltage generator, control electronics, collimator cone, and dynamic digital intraoral detector. During a tomosynthesis scan, each x-ray source is operated sequentially at fixed, nominal tube current of 7 mA and user-specified pulse width. Images are acquired by a digital intraoral detector and the reconstruction algorithm generates slice information in real time for operator review. In this study, the s-IOT system was characterized for tube output, dosimetry, and spatial resolution. Manufacturer specifications were validated, such as tube current, kVp, and pulse width. Tube current was measured with an oscilloscope on the analog output of the anode power supply. Pulse width, kVp, and peak skin dose were measured with a dosimeter with ion chamber and high voltage accessory. In-plane spatial resolution was evaluated via measurement of MTF and imaging of a line pair phantom. Spatial resolution in the depth direction was evaluated via artifact spread measurement. The size of the collimated radiation field was evaluated for compliance with FDA regulations. A dental phantom and human specimens of varying pathologies were imaged on a clinical 2D intraoral imaging system as well as s-IOT for comparison and to explore potential clinical applications. RESULTS: The measured tube current, kVp, and pulse width values were within 3% of the set values. A cumulative peak skin dose of 1.12 mGy was measured for one complete tomosynthesis scan using a 50-ms pulse per projection view. Projection images and reconstruction slices revealed MTF values ranging from 8.1 to 9.3 cycles/mm. Line pair imaging verified this result. The radiation field was found to meet the FDA requirements for intraoral imaging devices. Tomosynthesis reconstruction slice images of the dental phantom and human specimens provided depth resolution, allowing visibility of anatomical features that cannot be seen in the 2D intraoral images. CONCLUSIONS: The clinical prototype s-IOT device was evaluated and found to meet all manufacturer specifications. Though the system capability is higher, initial investigations are targeting a low-dose range comparable to a single 2D radiograph. Preliminary studies indicated that s-IOT provides increased image quality and feature conspicuity at a dose comparable to a single 2D intraoral radiograph.

Use of a Self-Instructional Radiographic Anatomy Module for Dental Hygiene Faculty Calibration.

Purpose: Dental hygiene educators often provide inconsistent instruction in clinical settings and various attempts to address the lack of consistency have been reported in the literature. The purpose of this pilot study was to determine if the use of a use of a self-instructional, radiographic anatomy (SIRA) module improved DH faculty calibration regarding the identifica-tion of normal intraoral and extraoral radiographic anatomy and whether its effect could be sustained over a period of four months.Methods: A convenience sample consisting of all dental hygiene faculty members involved in clinical instruction (N=23) at the University of North Carolina (UNC) was invited to complete the four parts of this online pilot study: a pre-test, review of the SIRA module, an immediate post-test, and a four-month follow-up post-test. Descriptive analyses, the Friedman's ANOVA, and the exact form of the Wilcoxon-Signed-Rank test were used to an-alyze the data. Level of significance was set at 0.05. Participants who did not complete all parts of the study were omitted from data analysis comparing the pre to post-test performance.Results: The pre-test response rate was 73.9% (N=17), and 88.2% (N=15) of those initial participants completed both the immediate and follow-up post-tests. Faculty completing all parts of the study consisted of: 5 full-time faculty, 5 part-time faculty, and 5 graduate teaching assistants. The Friedman's ANOVA revealed no statistically significant difference (P=0.179) in percentages of correct responses between the three tests (pre, post and follow-up). The exact form of the Wilcoxon-Signed-Rank test revealed marginal significance when comparing percent of correct responses at pre-test and immediate post-test (P=0.054), and no statistically significant difference when comparing percent of correct responses at immediate post-test and the follow-up post-test four months later (P=0.106).Conclusions: Use of a SIRA module did not significantly affect DH faculty test performance. Lack of statistical significance in the percentages of correct responses between the three tests may have been affected by the small number of participants completing all four parts of the study (N=15). Additional research is needed to identify and improve methods for faculty calibration.

Sinonasal Adenoid Cystic Carcinoma with Intracranial Invasion and Perineural Spread: A Case Report and Review of the Literature.

We present the case of a 51-year-old patient with sinonasal adenoid cystic carcinoma (SACC). Computed tomography (CT) and magnetic resonance imaging (MRI) exams revealed an expansive process in the right nostril accompanied with perineural spread and invasion to the floor of the middle cranial fossa. Due to the size of the tumor and brain involvement, the Head and Neck Tumor Board (HNTB) recommended radiochemotherapy treatment to decrease the size of the lesion. Presently, the patient is undergoing treatment without major complications.

A Comparison of Technique Errors using Two Radiographic Intra-oral Receptor-holding Devices.

PURPOSE: Technological advances in intra-oral receptors have resulted in film-holding devices that may or may not be interchangeable with photostimulable phosphor receptors. This study evaluated the number and types of technique errors that occurred when using PSP receptors with a standard film-holding device and a dual PSP/film-designed device. METHODS: The Rinn XCP-ORA® (Standard) and the Rinn Flip-Ray® PA device (Test) were compared using rectangular collimation. DenOptix® imaging plates (sizes 1 and 2) were used as receptors. Fourteen periapical (10-size 2 and 4-size 1) projections were exposed per full mouth series on each Dental X-ray Teaching and Training Replica with both devices. Five Dental X-ray Teaching and Training Replicas were exposed by 3 experienced radiographers. Data were analyzed using a paired t-test to determine differences in the performance scores between the 2 devices. Technique errors (receptor placement, vertical angulation, horizontal angulation and cone centering) were reported using frequencies. An experienced evaluator critiqued each projection. RESULTS: A total of 15 full mouth series (210 projections) were taken per device. The mean performance scores per device were 88.4 (standard device) and 88.1 (test device) and were not statistically different (p=0.88). Cone centering errors were the most common error observed in both the standard (36%) and test (43%) devices. Receptor placement errors occurred when using the standard (12%) and test (9%) devices. Vertical and horizontal errors were <2% for both devices. CONCLUSION: Devices designed for use with film may be used interchangeably with photostimulable phosphor receptors. Some difference was noticed between devices regarding error type and occurrence.

Intrapetrous Anastomosis between the Internal Jugular Vein and the Superior Petrosal Sinus: Cone Beam Computed Tomography Incidental Finding.

This is a case report of a 62-year-old male who presented to the Ear, Nose, and Throat clinic for a follow-up exam for hearing loss stemming from a fall from a horse in his infancy. A Cone Beam Computed Tomography (CBCT) examination revealed an intrapetrous communication between the internal jugular vein bulb and the superior petrosal sinus. Three-dimensional bone and soft tissues volume renderings were generated to demonstrate this incidental anatomical variant.

Technical Performance of Universal and Enhanced Intraoral Imaging Rectangular Collimators.

PURPOSE: The purpose of this study was to compare the number and type of technical errors between 2 rectangular collimators, time/motion effort and radiographer preference. METHODS: Subjects (n=17) were recruited to expose an 18 projection full mouth series (FMX) using Tru-Align™ (enhanced) and Rinn® (universal) collimator devices. Both FMXs were exposed using photostimulable phosphor (PSP) digital sensors on a DXTTR manikin with an intraoral x-ray unit. A 5-question survey evaluated ease of device use, time required and device preference. Data were analyzed using frequencies, paired t-test, ANOVA and least squares means using a general linear model. RESULTS: A lower mean number of technique errors per FMX occurred with the enhanced device (9.7) compared to the universal device (12.1). Collimator centering errors occurred 3-times more often with the universal device. The mean numbers of diagnostically unacceptable errors per FMX were similar (Universal=3.2 vs Enhanced=2.9). The least squares means adjusted model showed a statistically significant difference of errors between the 2 devices (p=0.0478) and errors by location when comparing posterior to anterior and posterior to bitewing (p<0.0001). Subjects (94%) preferred the enhanced device and found it easier to use compared to the universal device. Significantly less time was needed to expose an FMX (4 min) when using the enhanced device (p=0.0001). CONCLUSION: The enhanced device enabled subjects to expose diagnostically acceptable radiographs more efficiently with fewer collimator centering errors; however, it does so with a 35% greater exposure area and a concomitant increase in patient dose.

Acinic cell carcinoma of the parotid gland: a case report and review of the literature.

We report on a patient who was referred to the ENT service following an incidental finding on an MRI scan of the brain. It revealed a mass in the right parapharyngeal space, and additional imaging confirmed the presence of a solid cystic expansive mass with moderate enhancement following contrast media injection. The patient was treated with a total parotidectomy followed by radiotherapy. Currently, the patient is disease-free without any complications.

Giant undifferentiated oropharyngeal sarcoma: a case report and review of the literature.

We report on a patient who presented to the Ear, Nose and Throat (ENT) clinic with swelling of the neck, dysphagia, headache, dyspnea and stridor. Imaging studies revealed an expansive heterogeneous process to the left retropharyngeal region. The mass was ovoid in shape, displaying moderate enhancement after intravenous contrast administration. Subsequently, a biopsy revealed the presence of undifferentiated sarcoma. The patient was treated with chemotherapy followed by radiation therapy, but follow-up exams at 6 months posttreatment revealed that while the tumor was stable, it persisted. Consequently, the patient was enrolled in a palliative care and pain control program and is currently being followed.

Mandibular central mucoepidermoid carcinoma: a case report and review of the literature.

We report the case of a patient whose main complaint was swelling on the right side of the mandible when he presented to the Ear, Nose and Throat (ENT) Service. Imaging studies revealed a large homogeneous, multilocular, expansive lesion in the body of the right mandibular ramus. The lesion was poorly enhanced following intravenous contrast injection. The patient was treated with hemimandibular surgical resection, fibula free flap reconstruction and adjuvant radiotherapy. Currently, the patient is disease free and free of posttreatment complications.

Use of cone beam computed tomography in the diagnosis of superior semicircular canal dehiscence.

Superior semicircular canal dehiscence is a relatively new syndrome in the field of otology. It is of unknown etiology presenting with a variety of vestibular and auditory symptoms and radiologic findings play a crucial role in its diagnosis. Cone beam computed tomography has been shown to be a powerful tool in the field of otolaryngology. It is a three dimensional technique that uses lower radiation resulting in fewer artifacts and offers higher resolution when compared with multi-slice computed tomography. It is considered to be an excellent imaging modality for radiological exploration of the ear.

Utilization of blended learning to teach preclinical endodontics.

Blended learning (BL) is the integration of classroom learning with an online environment. The purpose of this study was to determine whether dental students who experienced BL in a preclinical endodontic course demonstrated better manual skills, conceptual knowledge, and learning experience compared to those experiencing traditional learning. All eighty-one students (100 percent) in a preclinical endodontics course agreed to participate and were assigned to either the traditional or BL group. A root canal procedure was used to determine the level of manual skills gained by each group. Pre- and post-intervention quizzes were given to all students to evaluate conceptual knowledge gained, and the students' perspectives on the methods were evaluated with a survey. The BL group scored better than the traditional group on the manual skills exercise at a statistically significant level (p=0.0067). There were no differences in the post-intervention quiz scores between the two groups, and the students' opinions were positive regarding BL. With BL, the students were able to learn and demonstrate dental skills at a high level.

Reducing the risk of intraoral radiographic imaging with collimation and thyroid shielding.

The 2007 modification by the International Commission on Radiation Protection of the calculation of effective dose from ionizing radiation has renewed interest in the concept of As Low As Reasonably Achievable exposure, and the technical approaches for reducing doses. This intraoral imaging study compared effective doses from circular and rectangular collimator modalities. A total of 18-image adult and 12-image child full mouth series were exposed using a 6 cm diameter circular collimator, a universal rectangular collimator, and an enhanced rectangular device for both adult and child phantoms. Rectangular collimation significantly reduced doses for adult exposures. In the child sample, only the universal rectangular collimator achieved significant dose reduction. While dose differences were attributed to both the size of the rectangular field and the use of thyroid shielding, the results indicated that the universal rectangular collimator used alone was more effective at reducing thyroid exposure than a thyroid shield used with circular collimation.

Oncocytoma of the parotid gland: a case report and review of the literature.

We report the case of a patient who presented to the ENT service with left facial swelling of 5 months duration. Imaging studies revealed a dense expansive mass confined to the inside of the left deep parotid lobule and moderate enhancement following contrast media injection. Subsequently, a biopsy confirmed the presence of an oncocytoma. The patient was treated with total parotidectomy, complete tumor resection and sparing facial nerve surgery. Today, the patient is disease free and has no complications.

Intraosseous hemangioma of the mandible: case report and review of the literature / Hemangioma intraóseo de la mandíbula: presentación de un caso y revisión de la literatura

We report on a two year old female patient who presented with expansion to the left side of the ramus and body of the mandibule. Imaging studies revealed a lesion with characteristics suggestive of vascular origin. Histopathological analysis determined the presence of an intraosseous Hemangioma. Embolization guided angiography of the left external carotid artery was performed followed by surveillance to monitor regression of the lesion.

Se presenta en una paciente de sexo femenino de dos años que presentó expansión del lado izquierdo de la rama y cuerpo de la mandíbula. Los estudios de imágenes revelaron una lesión con características sugerentes a un origen vascular. El análisis histopatológico determinó la presencia de un hemangioma intraóseo. Se realizó la embolización guiada por angiografía de la arteria carótida externa izquierda junto y seguimiento de control para supervisar la regresión de la lesión.

Multifocal extramedullary plasmocytoma of the sinonasal region: a case report and literature review / Plasmocitoma multifocal extramedular de la región sinonasal: reporte de un caso y revisión de la literatura

We report on a patient who presented to ENT services with right side epistaxis, frontal lobe headache, right infraorbital pain and the feeling of having a stuffy nose. CT and MRI were performed and later a biopsy confirmed the presence of sinonasal plasmocytoma. The Head and Neck oncology committee recommended radiotherapy as the choice of treatment. At the present time the patient is being followed on scheduled medical visits.

Se reporta el caso de un paciente que se presentó en el servicio de Otorrinolaringología con epistaxis, cefalea del lóbulo frontal derecho, dolor infraorbitario derecho y la sensación de tener la nariz tapada. Se realizaron TC y RNM, y luego una biopsia confirmó la presencia de un plasmocitoma nasosinusal. El comité de oncología de cabeza y cuello recomendó radioterapia como tratamiento de elección. En la actualidad, el paciente está en siguimiento y control en las visitas médicas regulares.

Skull base clear cell carcinoma, metastasis of renal primary tumor: a case report and literature review.

We report on a patient who presented with cranial nerve VI bilateral paresis, absence of pharyngeal reflex, dysarthria, right tongue deviation, and right facial paralysis. Imaging studies showed an expansive process in the cranial base with clivus and petrous apex osteolysis. A biopsy confirmed the presence of clear cell adenocarcinoma and suspicion of renal tumor metastases. Abdominal imaging studies revealed a mass in the right kidney. Consequently, radiotherapy was performed, and the patient was enrolled in a palliative care and pain control program.

Maxillary cuniculatum carcinoma: a case report and literature review / Carcinoma cuniculatum maxilar: presentación de un caso y revisión de la literatura

We report on a patient who presented to our clinic with a volume increase and pain at left maxillary region. A biopsy of the area was performed and the lesion was diagnosed as differentiated squamous cell carcinoma of the type cuniculatum. Due to the size of the tumor and compromise of vital intracraneal structures it was decided to perform surgical drainage and later is evaluated because of the tumor persistence to ultimately use palliative care...

Se presenta a una paciente que acudió a nuestra clínica con un aumento de volumen y dolor en región maxilar izquierda. Se realizó una biopsia del área y la lesión fue diagnosticada como carcinoma de células escamosas diferenciado de tipo cuniculatum. Debido al tamaño del tumor y el compromiso de estructuras intracraneales vitales, se decidió realizar un drenaje quirúrgico y posteriormente se evalúa la causa de la persistencia del tumor para finalmente entregar cuidados paliativos...