Use of cone beam computed tomography in otolaryngologic treatments

Gumbel distribution-based technique enables quantitative comparison between streak metal artifacts of multidetector row CT and cone-beam CT: a phantom study

Cone-beam computed tomography (CBCT), derived from multidetector row CT (MDCT), has a high spatial resolution and has recently been applied to various organs. One of the severe limitations common to CBCT and MDCT is metal artifacts. In particular, streak metal artifacts (SMAs) between multiple metal materials often hinder diagnosis. However, no studies have quantitatively compared the strength of SMAs in MDCT and CBCT. Nomura et al. reported an evaluation method specialized in SMAs of CBCT using the Gumbel distribution (GD), which can also be applied to SMAs of MDCT (Oral Surg Oral Med Oral Pathol Oral Radiol 131: 494-502, 2021, https://doi.org/10.1016/J.OOOO.2020.08.031 ). This study aimed to quantitatively compare SMAs occurring between titanium materials on MDCT and CBCT images using the GD-based method. The SMAs were investigated as follows: A hydroxyapatite block was sandwiched between two titanium rods to generate an SMA. They were placed in an acrylic phantom, simulating a human head, and scanned using an MDCT scanner and two CBCT scanners. The obtained images were analyzed using Gumbel plots and location parameters, and the SMA strength was calculated. The results showed that the SMAs on the MDCT images were significantly weaker than those on the CBCT images. In the CBCT scans, a smaller volume CT dose index value caused stronger SMAs. These results indicate that MDCT is more advantageous than CBCT in terms of SMA reduction when bone morphology between titanium materials must be evaluated. The characteristic should be considered in clinical cases.

Diagnostic usefulness of cone-beam computed tomography versus multi-detector computed tomography for sinonasal structure evaluation

Objective

Cone-beam computed tomography (CBCT) is a promising imaging modality for sinonasal evaluation, with advantages of relatively low radiation dose, low cost, and quick outpatient imaging. Our study aimed to compare the diagnostic performance and image quality of CBCT with those of multi-detector computed tomography (MDCT) with different slice thickness.

Methods

We retrospectively reviewed 60 consecutive patients who had undergone both CBCT and MDCT. MDCT images was reconstructed with 1 and 3 mm slice thickness. The quantitative image quality parameters (image noise, signal-to-noise ratio [SNR], and contrast-to noise ratio [CNR] were calculated and compared between the two imaging modalities. Two observers (ENT surgeon and neuroradiologist) evaluated the presence of seven sinonasal anatomic variations in each patient and interobserver agreements were analyzed. The diagnostic performance of CBCT (0.3 mm) and MDCT (3 mm) was assessed and compared with that of high resolution MDCT (1 mm), which is considered as the gold standard.

Results

The image noise was significantly higher and SNR and CNR values were lower in the CBCT (0.3 mm) group than in the MDCT groups (1 and 3 mm). The diagnostic performance of CBCT (0.3 mm) was similar to that of MDCT (1 mm) and superior to that of MDCT (3 mm). The highest interobserver agreement was for high resolution MDCT (1 mm), followed by CBCT (0.3 mm), and MDCT (3 mm).

Conclusion

Considering its low radiation dose, low cost, and ease of clinical access, CBCT may be a useful imaging modality for as first line sinonasal evaluation and repeated follow up.Study design: Retrospective study in a tertiary referral university center.Level of evidence: NA.

Analysis of Lacrimal Duct Morphology from Cone-Beam Computed Tomography Dacryocystography in a Japanese Population

Purpose

The dacryoendoscope is a practical instrument for the examination and the treatment of lacrimal duct obstruction. Nevertheless, as it is a rigid fiberscope, manipulation of the endoscope is somewhat affected by the patient’s lacrimal duct alignment and the skeletal structure of the face. The morphology and inclination of the lacrimal duct vary among individuals and ethnic groups. We aimed to evaluate the alignment of the lacrimal duct from the perspective of endoscopic maneuverability in a Japanese population.

Methods

This retrospective study analyzed the cone-beam computed tomography dacryocystography (CBCT-DCG) images of 102 patients diagnosed with unilateral primary acquired nasolacrimal duct obstruction (PANDO) at Ehime University Hospital from December 2015 to May 2021. The following parameters of the lacrimal duct on the contralateral side of unilateral PANDO were investigated: (1) angle formed by the superior orbital rim–internal common punctum–nasolacrimal duct opening, (2) angle formed by the lacrimal sac and the nasolacrimal duct, (3) length of the lacrimal sac, and (4) length of the nasolacrimal duct.

Results

Measurements of the above parameters were (1) 10.2° ± 7.8° (range, −11° to +27°), (2) −6.3° ± 14.1° (range, −43° to +40°), (3) 8.9 ± 2.3 mm (range, 4.3–17.1), and (4) 13.2 ± 2.7 mm (range, 5.7–20.7), respectively. The Shapiro–Wilk test demonstrated that the values of all parameters, except (3), followed a normal distribution (p = 0.55, 0.30, 0.0002, and 0.39, respectively). No significant difference was found between the female and male groups (p > 0.05).

Conclusion

This study reported anthropometric analysis data of the morphology of the lacrimal ducts using CBCT-DCG in a Japanese population. In our cohort, the line from the superior orbital rim through the internal common punctum to the nasolacrimal duct opening inclined anteriorly in 92% of the patients.

[Applications of cone beam computed tomography of the craneofacial structure in medical specialties. A review]

Cone-beam computed tomography (CBCT) of the craniofacial structure has demonstrated its usefulness in the dental area during the last decades, thus it has become a fundamental tool in the diagnosis, planning, and evaluation of treatment, and although it was not developed for the exclusive use in dentistry, as it is commonly considered, it is used in other areas such as medicine. It is specifically used in the head and neck area where different medical specialties interact, and at the same time these interact with dental specialties, so knowing the advantages of CBCT over different imaging technologies in the medical area is necessary. The purpose of this review was to describe the applications of observation, diagnosis, planning, and evolution of treatments using maxillofacial HSCT in different medical specialties. This work highlights the use of TCHC in different medical applications and highlights where it is most useful compared to other technologies.

Three-dimensional modeling and automatic analysis of the human nasal cavity and paranasal sinuses using the computational fluid dynamics method

PURPOSE

The goal of this study was to develop a complete workflow allowing for conducting computational fluid dynamics (CFD) simulation of airflow through the upper airways based on computed tomography (CT) and cone-beam computed tomography (CBCT) studies of individual adult patients.

METHODS

This study is based on CT images of 16 patients. Image processing and model generation of the human nasal cavity and paranasal sinuses were performed using open-source and freeware software. 3-D Slicer was used primarily for segmentation and new surface model generation. Further processing was done using Autodesk^® Meshmixer TM. The governing equations are discretized by means of the finite volume method. Subsequently, the corresponding algebraic equation systems were solved by OpenFOAM software.

RESULTS

We described the protocol for the preparation of a 3-D model of the nasal cavity and paranasal sinuses and highlighted several problems that the future researcher may encounter. The CFD results were presented based on examples of 3-D models of the patient 1 (norm) and patient 2 (pathological changes).

CONCLUSION

The short training time for new user without a prior experience in image segmentation and 3-D mesh editing is an important advantage of this type of research. Both CBCT and CT are useful for model building. However, CBCT may have limitations. The Q criterion in CFD illustrates the considerable complication of the nasal flow and allows for direct evaluation and quantitative comparison of various flows and can be used for the assessment of nasal airflow.

Evaluation of factors affecting the association between thickening of sinus mucosa and the presence of periapical lesions using cone beam CT

AIM

To evaluate the effect of various parameters of periapical lesion(s) on the amount and type of mucosal thickening using cone beam CT images.

METHODOLOGY

CBCT scans of 1000 patients were evaluated retrospectively for the presence of apical lesions in maxillary posterior teeth associated with sinus mucosal thickening. The number of cases with pathological mucosal thickening was recorded and classified according to the amount and type of mucosal thickening. The parameters evaluated as the cause of mucosal thickening were the type and number of posterior teeth, number of root(s), diameter of the periapical lesion and distance between maxillary sinus and lesion. Descriptive statistics and multiple logistic regression was used for data analyses. Spearman's correlation coefficient was used for pair-wise comparisons. Intrarater reliability was tested by Cohen's kappa.

RESULTS

Mucosal thickening associated with periapical lesions was determined in 48% of 202 cases. The most frequently detected extent of mucosal thickening was type 3 (42%), whereas flat type thickening (59%) was the most frequent type. The tooth most frequently associated with mucosal thickening was the maxillary first molar (44%). Parameters significantly affecting the extent of mucosal thickening were gender, number of roots, number of teeth with periapical lesions and diameter of periapical lesions (P < 0.05). The single parameter with an association with the type of mucosal thickening was the number of roots with an apical lesion (P < 0.05).

CONCLUSION

Mucosal thickening associated with periapical lesions was observed in almost 50% of all mucosal thickening cases. Therefore, collaboration amongst endodontists and otolaryngologists is mandatory to provide successful treatment and prevent recurrence of maxillary sinusitis.

Bilateral Fracture of the Handle Malleus: A Case Report and Review of the Literature

Malleus fracture is a rare condition. Usually, the handle of the malleus is involved, and we do not find reports in the literature of this condition in the bilateral presentation. It is present as sudden conductive hearing loss commonly after digital manipulation of the external auditory canal. The diagnosis is based principally on clinical examination by otomicroscopy and audiometry. Cone-beam computed tomography emerging as a powerful tool in the field of otolaryngology, especially for explorations of paranasal sinuses and temporal bone, due to imaging with a high resolution and few artifacts with lower dose radiation in comparison with multislice computed tomography.

Radiological Study of Maxillary Sinus using CBCT: Relationship between Mucosal Thickening and Common Anatomic Variants in Chronic Rhinosinusitis

INTRODUCTION

Inflammatory diseases of the maxillary sinus favour the thickening of the sinus mucosa. Therefore, it might be possible to establish a radiological, pathological threshold of mucosal thickening. Furthermore, there is an association between common anatomic variants of the nose and maxillary mucosal thickening.

AIM

To define the pathological thickening of maxillary sinus mucosa and its association with the presence of common anatomic variants (concha bullosa, Haller's cell and accessory maxillary ostium).

MATERIALS AND METHODS

From March 2014 to February 2016, Two hundred patients underwent Cone Beam Computed Tomography (CBCT) of the paranasal sinus. We conducted this retrospective study of total 70 patients, 34 patients i.e., a total of 68 meatus-maxillary units (study group - those affected by Chronic Rhinosinusitis (CRS) and another 36 patients i.e., a total of 72 meatus maxillary units (control group - without symptoms of CRS). We assessed the degree of thickening of the sinus mucosa distinguishing between ≥ 2mm or ≤ 2mm, than we analysed the behaviour of the thickness in the study group and in the control group. Chi-Square test was used to compare mucosal thickening between study and control group and the presence of some common anatomic variants or closure of maxillary ostium.

RESULTS

In the study group we observed a clear association between maxillary mucosal thickening ≥ 2mm and CRS (p<0.01). We however, observed no association between the presence of common anatomic variations and thickening of the maxillary mucosa and between the presence of common anatomic variations and the study group. Instead, using a binary logistic regression, we observed a significant association (p<0.01) between closure of natural ostium of the maxillary sinus and mucosal thickening or between closure of natural ostium and study group.

CONCLUSION

We believe that a thickening of the maxillary mucosa ≥ 2mm and closure of natural maxillary ostium are statistically associated with CRS. The common anatomical variants do not seem to be associated with this condition.

Optimized imaging of the midface and orbits

A variety of imaging techniques are available for imaging the midface and orbits. This review article describes the different imaging techniques based on the recent literature and discusses their impact on clinical routine imaging. Imaging protocols are presented for different diseases and the different imaging modalities.

Diagnostic accuracy of cone-beam computed tomography in the evaluation of chronic rhinosinusitis

INTRODUCTION

This study assessed the agreement of cone-beam computed tomography (CBCT) scan and sinus endoscopy findings and attempted to find a diagnostic accuracy of CBCT in patients with chronic rhinosinusitis (CRS).

METHODS

Forty-two patients with CRS referred to the Aria and 22 Bahman Hospitals in Mashhad, Iran, during the year 2011 were included in this cross-sectional study. Paranasal sinus CBCT scanning and endoscopy were performed in all patients. The sensitivity, specificity, positive and negative predictive values (PPV and NPV), and accuracy of CBCT were determined, and the agreement between CBCT and endoscopy findings was evaluated.

RESULTS

In most of our findings, except for infundibulum thickening, there was a strong agreement between CBCT and paranasal sinus endoscopy, with a kappa coefficient >0.80 (p < 0.05). The sensitivity, specificity, PPV, NPV, and accuracy of CBCT were >80% for most of the findings, except for infundibulum thickening and septal deviation.

CONCLUSION

CBCT has nearly the same diagnostic accuracy as sinus endoscopy. The accuracy of CBCT scanning is high, and CBCT findings are well correlated with sinus endoscopy findings. Considering its high accuracy and lower costs and radiation doses, CBCT may be a proper alternative method for diagnostic sinus endoscopy in the assessment of CRS in patients with a contraindication for sinus endoscopy.

Dentomaxillofacial imaging with panoramic views and cone beam CT

Panoramic and intraoral radiographs are the basic imaging modalities used in dentistry. Often they are the only imaging techniques required for delineation of dental anatomy or pathology. Panoramic radiography produces a single image of the maxilla, mandible, teeth, temporomandibular joints and maxillary sinuses. During the exposure the x-ray source and detector rotate synchronously around the patient producing a curved surface tomography. It can be supplemented with intraoral radiographs. However, these techniques give only a two-dimensional view of complicated three-dimensional (3D) structures. As in the other fields of imaging also dentomaxillofacial imaging has moved towards 3D imaging. Since the late 1990s cone beam computed tomography (CBCT) devices have been designed specifically for dentomaxillofacial imaging, allowing accurate 3D imaging of hard tissues with a lower radiation dose, lower cost and easier availability for dentists when compared with multislice CT. Panoramic and intraoral radiographies are still the basic imaging methods in dentistry. CBCT should be used in more demanding cases. In this review the anatomy with the panoramic view will be presented as well as the benefits of the CBCT technique in comparison to the panoramic technique with some examples. Also the basics as well as common errors and pitfalls of these techniques will be discussed. Teaching Points • Panoramic and intraoral radiographs are the basic imaging methods in dentomaxillofacial radiology.• CBCT imaging allows accurate 3D imaging of hard tissues.• CBCT offers lower costs and a smaller size and radiation dose compared with MSCT.• The disadvantages of CBCT imaging are poor soft tissue contrast and artefacts.• The Sedentexct project has developed evidence-based guidelines on the use of CBCT in dentistry.

Prediction of the attachment site of sinonasal inverted papillomas by preoperative imaging

OBJECTIVE

Accurate preoperative identification of the attachment site is the key to the successful surgical management of sinonasal inverted papillomas (IPs). This study investigated the value of preoperative imaging to identify the attachment sites of IPs.

METHODS

We analyzed I 0 consecutive patients with pathologically proven IPs. Two radiologists predicted the attachment sites of IPs from computed tomography (CT), 3.0 Tesla magnetic resonance imaging (3.0T MRI), 1.5T MRI, and CT plus 3.0T MRI. The actual tumor attachment sites were confirmed via pathological examination of specimens and compared with the predicted sites.

RESULTS

Computed tomography showed the highest sensitivity (P < .0001), although both MRI formats showed greater specificity (P < .0001). The sensitivity of MRI plus CT was equal to that of CT and better than that of MRI (P < .0001), whereas its specificity was better than that of CT (P < .0001) and comparable to that of MRI. Prediction using 3.0T MRI appeared slightly superior to that using 1.5T MRI in terms of sensitivity and specificity, although the differences were not significant.

CONCLUSION

Computed tomography and MRI had different features for prediction of sinonasal IP attachment sites. Preoperative CT plus MRI provided more useful information than CT or MRI alone.

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.

Association between periapical lesions and maxillary sinus mucosal thickening: a retrospective cone-beam computed tomographic study

INTRODUCTION

Odontogenic infections are a common cause of maxillary sinusitis. This study aimed to evaluate the relationship between teeth with periapical lesions or periodontal disease and sinus mucosal thickening using cone-beam computed tomography (CBCT) imaging.

METHODS

CBCT scans of 243 patients (485 sinuses) were evaluated retrospectively for the presence of periapical lesions and/or periodontal disease in posterior maxillary teeth and associated sinus mucosal thickening. Thickening >2 mm was considered pathological and was categorized by degree (2-5 mm, 5-10 mm, and >10 mm) and type (flat or polypoid). Descriptive, bivariate, and multivariate statistical analyses were performed.

RESULTS

Mucosal thickening >2 mm was observed in 147 (60.5%) patients and 211 (44.6%) sinuses and was mostly of a "flat" type. Bivariate analysis revealed significant associations between mucosal thickening >2 mm and sex (males), age (>60 years), and teeth with periapical lesions and periodontal disease (P ≤ .027). Multivariate regression analysis identified only sex (males, odds ratio = 1.98, P = .004) and teeth with periapical lesions (odds ratio = 9.75, P < .001) to be associated with mucosal thickening >2 mm.

CONCLUSIONS

Sinus mucosal thickening is a common radiographic finding, which is more likely to be observed in males (2×) and in relation to teeth with periapical lesions (9.75×).

Cone-beam computed tomographic analysis of sinus membrane thickness, ostium patency, and residual ridge heights in the posterior maxilla: implications for sinus floor elevation

OBJECTIVE

To determine, using cone-beam computed tomography (CBCT), the residual ridge height (RRH), sinus floor membrane thickness (MT), and ostium patency (OP) in patients being evaluated for implant placement in the posterior maxilla.

MATERIALS AND METHODS

CBCT scans of 128 patients (199 sinuses) with ≥1 missing teeth in the posterior maxilla were examined. RRH and MT corresponding to each edentulous site were measured. MT >2 mm was considered pathological and categorized by degree of thickening (2-5, 5-10 mm, and >10 mm). Mucosal appearance was classified as "normal", "flat thickening", or "polypoid thickening", and OP was classified as "patent" or "obstructed". Descriptive and bivariate statistical analyses were performed.

RESULTS

MT >2 mm was observed in 60.6% patients and 53.6% sinuses. Flat and polypoid mucosal thickening had a prevalence of 38.1% and 15.5%, respectively. RRH ≤4 mm was observed in 46.9% and 48.9% of edentulous first and second molar sites, respectively. Ostium obstruction was observed in 13.1% sinuses and was associated with MT of 2-5 mm (6.7%), 5-10 mm (24%), and >10 mm (35.3%, P < 0.001). Polypoid mucosal lesions were more frequently associated with ostium obstruction than flat thickenings (26.7% vs. 17.6%, P < 0.001).

CONCLUSION

Thickened sinus membranes (>2 mm) and reduced residual ridge heights (≤4 mm) were highly prevalent in this sample of patients with missing posterior maxillary teeth. Membrane thickening >5 mm, especially of a polypoid type, is associated with an increased risk for ostium obstruction. In the presence of these findings, an ENT referral may be beneficial prior to implant-related sinus floor elevation.