Imaging of the paranasal sinuses and in-office CT

Analysis of sphenoid sinus and ethmoid sinus volume and asymmetry by sex: A 3D-CT study

PURPOSE

To measure the volume of the sphenoid and ethmoid sinuses and to analyse the asymmetry index values by age/gender.

METHODS

Three-dimensional (3D) Computed Tomography (CT) images of 150 individuals (75 females, 75 males) of both sexes between the ages of 18-75 were included in our study. Sphenoid and ethmoid sinus volumes were measured using the 3D Slicer software package on these images, and the asymmetry index was calculated.

RESULTS

In our study, mean sphenoid sinus volume (female right: 4264.4 mm3, left: 3787.1 mm3; male right: 5201.1 mm3, left: 4818.2 mm3) and ethmoid sinus volume (female right: 3365.1 mm3, left: 3321.2 mm3; male right: 3440.9 mm3, left: 3459.5 mm3) were measured in males and females. Left sphenoid sinus values of males were statistically higher than females (p = 0.036). No statistically significant relationship existed between age, sinus volumes, and asymmetry index (p > 0.05). A statistically weak positive correlation existed between males' left sphenoid and ethmoid sinus volume (rho = 0.288; p = 0.012). There was no statistical relationship between asymmetry index in the whole group (p > 0.05). A statistically weak negative correlation was found between sphenoid and ethmoid sinus asymmetry index in males (rho=-0.352; p = 0.002). There was no statistical relationship between asymmetry index in females (p > 0.05).

CONCLUSION

Knowing paranasal sinus morphology, morphometry, and asymmetry index value will be significant for preoperative and postoperative periods.

The Relationship Between an Accessory Maxillary Ostium and Variations in Structures Adjacent to the Maxillary Sinus without Polyps

Introduction  The maxillary sinus and its variations are very important to dentistry and rhinology.

Objective  To investigate the effect of the accessory maxillary ostium (AMO) on the variations of adjacent structures of the maxillary sinus.

Methods  The computed tomography (CT) images of 400 patients were retrospectively evaluated. The prevalence of AMO was calculated. The relationship between morphological variations of adjacent structures of maxillary sinus such as agger nasi cell (ANC), Haller cell (HC), nasal septum deviation (NSD), hypertrophy of inferior concha (HIC), pneumatization of middle concha (PMC), mucus retention cyst (MRC), mucosal thickening (MT), and maxillary sinusitis (MS), as well as the presence of AMO, were investigated.

Results  Presence of AMO was diagnosed in 42 patients (10.5%), having been found in 4.5% of the patients only on the right side, in 1.25% of the patients only on the left side, and in 4.75% of the patients on both sides. There is an increasing incidence of ANC, HC, NSD, HIC, and PMC in the presence of AMO and MS. There is a decreasing incidence of MRC in the presence of AMO. Furthermore, AMO does not affect the incidence of MT.

Conclusion  This study showed that most parameters, except for MRC and MT, had increasing incidence in the presence of AMO. It is important for radiologists and rhinologists to have knowledge about the location of AMO and the presence of variations of MS adjacent structures to avoid surgical complications.

Billing patterns for in-office computerized tomography scans of the face/sinus by otolaryngologists

PURPOSE

To evaluate billing trends, Medicare reimbursement, and practice setting for Medicare-billing otolaryngologists (ORLs) performing in-office face computerized tomography (CT) scans.

METHODS

This retrospective study included data on Medicare-billing ORLs from Medicare Part B: Provider Utilization and Payment Datafiles (2012-2018). Number of Medicare-billing ORLs performing in-office CT scans, and total sums and medians for Medicare reimbursements, services performed, and number of patients were gathered along with geographic and practice-type distributions.

RESULTS

In 2018, roughly 1 in 7 Medicare-billing ORLs was performing in-office CT scans, an increase from 1 in 10 in 2012 (48.2% growth). From 2012 to 2018, there has been near-linear growth in number of in-office CT scans performed (58.2% growth), and number of Medicare fee-for-service (FFS) patients receiving an in-office CT scan (64.8% growth). However, at the median, the number of in-office CT scans performed and number of Medicare FFS patients receiving an in-office CT, per physician, has remained constant, despite a decline of 42.3% (2012: $227.67; 2018: $131.26) in median Medicare reimbursements.

CONCLUSION

Though sharp declines have been seen in Medicare reimbursement, a greater proportion of Medicare-billing ORLs have been performing in-office face CT scans, while median number of in-office CT scans per ORL has remained constant. Although further investigation is certainly warranted, this analysis suggests that ORLs, at least in the case of the Medicare FFS population, are utilizing in-office CT imaging for preoperative planning, pathologic diagnosis, and patient convenience, rather than increased revenue streams. Future studies should focus on observing these billing trends among private insurers.

Cone-Beam Computed Tomography Allows Accurate Registration to Surgical Navigation Systems: A Multidevice Phantom Study

Background

Cone-beam computed tomography (CBCT) is a fast imaging technique with a substantially lower radiation dosage than conventional multidetector computed tomography (MDCT) for sinus imaging. Surgical navigation systems are increasingly being used in endoscopic sinus and skull base surgery, reducing perioperative morbidity.

Objective

To investigate CBCT as a low-radiation imaging modality for use in surgical navigation.

Methods

The required field of view was measured from the tip of the nose to the posterior clinoid process anteroposteriorly and the nasolabial angle to the roof of the frontal sinus superoinferiorly on 50 consecutive MDCT scans (male = 25; age = 17–85 years). A phantom head was manufactured by 3-dimensional printing and imaged using 3 CBCT scanners (Carestream, J Morita, and NewTom), a conventional MDCT scanner (Siemens), and highly accurate laser scanner (FARO). The phantom head was registered to 3 surgical navigation systems (Brainlab, Stryker, and Medtronic) using scans from each system.

Results

The required field of view (mean ± standard deviation) was measured as 107 ± 7.6 mm anteroposteriorly and 90.3 ± 9.6 mm superoinferiorly. Image error deviations from the laser scan (median ± interquartile range) were comparable for MDCT (0.19 ± 0.09 mm) and CBCT (CBCT 1: 0.15 ± 0.11 mm; CBCT 2: 0.33 ± 0.18 mm; and CBCT 3: 0.13 ± 0.13 mm) scanners. Fiducial registration error and target registration error were also comparable for MDCT- and CBCT-based navigation.

Conclusion

CBCT is a low-radiation preoperative imaging modality suitable for use in surgical navigation.

Characterization of the Maxillary Sinus Using Cone Beam Computed Tomography. A Retrospective Radiographic Study

PURPOSE

To analyze the anatomical findings and alterations of the maxillary sinus in asymptomatic patients observed by cone beam computed tomography.

MATERIALS AND METHODS

A cross-sectional retrospective study of the anatomical variations and alterations of the maxillary sinus was made in 160 patients-71 males (44.3%) and 89 females (55.6%), with an age range of 18 to 74 years-measuring the thickness of the Schneiderian membrane and the cortical thickness of the lower margin of the maxillary sinus (in its most caudal portion), and correlations among the different study variables were assessed.

RESULTS

Sinus pneumatization was the most frequent anatomical finding (81.3%). A negative correlation was observed between the thickness of the Schneiderian membrane and the presence of Underwood septa (P < 0.005). Mucosal thickening of more than 2 mm was directly correlated with the presence of maxillary sinus lesions (opacification, discontinuity of the floor of the sinus, polypoid lesions, or air-liquid levels).

CONCLUSION

The presence or absence of septa seems to be related to the thickness of the Schneiderian membrane.

The Preoperative Sinus CT: Avoiding a "CLOSE" Call with Surgical Complications

Although functional endoscopic sinus surgery is an effective means of treating patients with recurrent and refractory sinusitis, the procedure is not without risk of serious surgical complications. Preoperative computed tomography (CT) affords radiologists the opportunity to prospectively identify anatomic variants that predispose patients to major surgical complications; however, these critical variants are not consistently evaluated or documented on preoperative imaging reports. The purpose of this review is to illustrate important anatomic variants and landmarks on the preoperative sinus CT with a focus on those that predispose patients to surgical complications. These critical variants and landmarks can be quickly recalled and incorporated into the preoperative imaging report through the use of the mnemonic "CLOSE": Cribriform plate, Lamina papyracea, Onodi cell, Sphenoid sinus pneumatization, and (anterior) Ethmoidal artery. This approach will greatly enhance the value of the preoperative imaging report for referring otolaryngologists and help reduce the risk of surgical complications. (©) RSNA, 2016 Online supplemental material is available for this article.

A Controlled, Randomized Clinical Study on the Impact of Treatment on Antral Mucociliary Clearance: Uncinectomy Versus Balloon Sinuplasty

OBJECTIVES

To find out the effect of minimal invasive sinus surgery and balloon sinuplasty on mucociliary clearance and compare different methods of measuring mucociliary clearance.

METHODS

Twenty-nine patients with chronic rhinosinusitis were randomized in 2 operative groups (uncinectomy or balloon sinuplasty). Before and 6 months after the treatment, patients filled out a quality of life questionnaire (Sino Nasal Outcome Test-22 [SNOT-22]), and mucociliary clearance was measured with endoscope and gamma camera after 0.03 ml of saccharine, methylene-blue dye, and human albumin labeled with Tc99m was introduced to the bottom of maxillary sinuses.

RESULTS

In uncinectomy group, SNOT-22 score decreased, but treatment had no effect on mucociliary clearance. Based on saccharine test, smoking was associated with worse mucociliary clearance (r = 0.618, P < .05). Methylene blue test results associated with saccharine test (r = 0.434, P < .05) and Tc99m-labeled tracer technique (r = 0.261, P = .039) separately.

CONCLUSION

Treatment positively affects patients' quality of life; however, it has no effect on mucociliary clearance. There was a statistically significant correlation between the Tc99m-labeled tracer technique and the methylene blue technique. The saccharine technique was even less accurate, but it can be useful in clinical practice because it is a quick, easy, and safe technique.

Computed tomography imaging practice patterns in adult chronic rhinosinusitis: survey of the American Academy of Otolaryngology-Head and Neck Surgery and American Rhinologic Society membership

BACKGROUND

The objective of this study was to assess the current practice patterns of computed tomography (CT) imaging for diagnosis and management of adult chronic rhinosinusitis (CRS).

METHODS

A 29-item, electronic, Web-based physician survey was disseminated to the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) and American Rhinologic Society (ARS) membership from November 2012 to January 2013.

RESULTS

A total of 331 otolaryngologists completed the survey. Seventy-five percent of respondents did not obtain confirmatory CT imaging prior to initiating medical therapy for CRS. A typical diagnostic scan was considered to be a 3-mm coronal CT with or without 3-mm axial images for 50.6% of participants. On average, the respondents obtained 1 (58.8%) or 2 (36.6%) CT scans prior to proceeding with sinus surgery. CT scanning was most commonly performed in a hospital radiology department (76.4%), followed by a free-standing imaging center (44.5%). An in-office CT scanner was owned by 24.5% of the respondents, mostly commonly a cone beam CT (74.0%) scanner. Most respondents (87.1%) did not experience problems with carriers denying ability to image or reimbursing for scans. Overall, 68.4% of the respondents were unaware of the dosage of radiation delivered by the scanner used for CT acquisition.

CONCLUSION

This survey provides a snapshot of the current utility of CT imaging in the management paradigm for CRS. Given that most are unaware of the delivered radiation dose, this clearly represents an important area of improvement in the knowledge gap.

Patient knowledge and perception of computed tomography scan in the management of chronic rhinosinusitis symptoms

OBJECTIVES/HYPOTHESIS

The objective of this study was to report patients' knowledge and comfort level with computed tomography (CT) imaging for sinus disease and evaluate patient willingness to undergo empiric medical therapy (EMT) versus CT-directed therapy (CTDT).

STUDY DESIGN

Prospective survey study.

METHODS

A 22-item survey was administered to patients with nasal/sinus symptoms in a tertiary care rhinology clinic. Questions elicited patient demographics, imaging history, and knowledge/comfort regarding imaging-related radiation exposure. Patients were presented with the theoretical choice of EMT versus CTDT, given the expected positive predictive value, in chronic rhinosinusitis (CRS) management.

RESULTS

Two hundred patients (52% female, age range 18-83 years) participated. Of these, 85% had symptoms for over 3 months. Only 91 patients (45.5%) were aware that CT imaging involved radiation exposure. Prior CT experience and past sinus surgery (P < .05), but not sex or education level, were associated with increased comfort with CT imaging. Most patients (78%) preferred CTDT over EMT. If a CT sinus was recommended, 77 patients (38.5%) had concerns, of which 26% identified radiation exposure as the leading concern. The majority (70%) were unsure about the relative radiation dose of a conventional CT.

CONCLUSIONS

Patients with CRS symptoms prefer CTDT over EMT if a diagnosis cannot be established definitively using exam findings. Although most patients deferred to the physician regarding the decision to utilize CT imaging, there is low awareness of CT-related radiation exposure, and a significant minority of patients have radiation-related concerns with regard to medical imaging for nasal and sinus symptoms.

Cost efficient workup and management of patients with chronic rhinosinusitis - challenges and unmet needs

Chronic rhinosinusitis (CRS) is a common disease, estimated to occur in 12-16% of the United States population. This prevalence creates a significant health burden with an estimated 15 million ambulatory visits for the condition annually. Consequently, practice guidelines have been designed to assist both the primary care provider and specialist in establishing a CRS diagnosis and prescribing effective treatment for CRS. The guidelines for CRS diagnosis have evolved since the United States Rhinosinusitis Task Force first published its symptom-based guidelines in 1997. Contemporary practice guidelines still require 12 weeks of appropriate symptoms, but now include corroboration of objective sinonasal inflammation demonstrated on physical exam, imaging, or endoscopy to arrive at a CRS diagnosis. While these diagnostic criteria are seemingly straightforward and are regarded as the gold standard for the diagnosis, the appropriate timing of imaging and endoscopy remain unspecified and continue to present challenges for both primary care and specialty providers. These considerations have to be measured by the direct and indirect costs of the diagnostic workup including office visits, CT scanning, endoscopy, as well as the potential for overuse of treatment modalities such as antibiotics and steroid medications. The goal of this review is to update the primary care provider and otolaryngologist on current evidence regarding the diagnosis and treatment of chronic rhinosinusitis, including the costs and timing of endoscopy and imaging.

The CT and MRI observations of small cell neuroendocrine carcinoma in paranasal sinuses

Background

Primary small cell neuroendocrine carcinoma (SNEC) of paranasal sinuses is an extremely rare malignant tumor known for its aggressive clinical behavior.

Methods

Nineteen patients with SNEC in paranasal sinuses by magnetic resonance imaging (MRI) (n = 19) and computerized tomography (CT) and MRI (n = 18) were retrospectively studied. CT and MRI were undertaken to investigate tumor features.

Results

The lesions were located in the ethmoidal sinus (n = 6), maxillary sinus (n = 4), and bilateral sphenoid sinus (n = 9). All lesions showed a symmetry or ‘pigeon’ pattern in the bilateral sphenoid sinus (n = 9). On CT scan, the lesions showed to be isodense (n = 3) or mild hyper-dense (n = 15). Bone changes included bony absorption or sclerosis (n = 3) and moth-eaten bone destruction (n = 16). Mild cystic components were visible in five patients with SNEC. There was no evidence of calcification in any of the SNEC tumors. The lesions were isointense on T₁WI and isointense (n = 6) or mild hyper-intense on T₂WI (n = 13). The lesions showed mild or moderate homogeneous enhancement after the administration of a contrast agent. The aggressive nature of the tumors was demonstrated by invasion of adjacent structures, which showed involvement of the nasal cavity (n = 17), orbits (n = 15), pterygopalatine fossa (n = 9), ethmoidal sinus and sphenoid (n = 5), clivus ossis occipitalis (n = 2), cavernous sinus and internal carotid canal (n = 5), optic canal (n = 3), jugular fossa (n = 2), anterior fossa (n = 2), apex partis petrosae ossis temporalis (n = 3), meninges (n = 2), temporal fossa and infratemporal fossa (n = 4), and pharyngonasal cavity and parapharyngeal space (n = 3). There was evidence of distant metastasis in five (lung) and one (liver) of the tumors. Fifteen patients (15/19, 78.9%) expired within 5 years of the initial diagnosis, and the other patients are currently still alive.

Conclusions

A tumor exhibiting mild or moderate homogeneous enhancement together with a symmetry or ‘pigeon’ pattern in the bilateral ethmoidal sinus may be considered as specific MRI features.

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.

Sinus imaging for diagnosis of chronic rhinosinusitis in children

Chronic rhinosinusitis (CRS) is a relatively common disease in children but is often overlooked because at times the clinical symptoms are subtle and nonspecific. This makes imaging very important in the diagnosis. Among the different techniques, plain radiography has limited utility,whereas CT scan and MRI have a major role in evaluating the modifications caused by the disease. In particular, a CT scan provides higher resolution of bone and soft tissue and removes the overlapping structures that are present in conventional radiography. CT is recommended in isolated sphenoid sinusitis, is essential in diagnosing fungal sinusitis, and is the technique of choice when orbital complications are suspected. MRI allows investigation of not only the morphology of structures, but their intrinsic biophysical and biochemical properties, such as water content, cellular density, lipid or blood product deposits, and fibrosis. MRI allows better soft tissue differentiation and high spatial resolution images depicting fine details. When indicated, MRI with contrast gadolinium-based agents may better characterize the local disease extension or its diffusion beyond paranasal and nasal cavities and has excellent contrast resolution. A combination of CT and MRI is useful in cases of diagnostic difficulties,especially when complications are involved.

Radiologic reporting for paranasal sinus computed tomography: a multi-institutional review of content and consistency

OBJECTIVES/HYPOTHESIS

To optimize clinical care, radiologic reporting should consistently include clinically pertinent information. The purpose of this study was to: 1) determine the current satisfaction of otolaryngologists with paranasal sinus computed tomography (CT) radiologic reporting and 2) evaluate the comprehensiveness of paranasal sinus CT radiologic reporting.

STUDY DESIGN

Two parts: 1) A national survey of all practicing otolaryngologists in Canada and 2) a retrospective review of paranasal sinus CT scan radiologic reporting.

METHODS

A national survey of all Canadian otolaryngologists was conducted in September 2011. Questions were focused on eliciting the current satisfaction with sinus CT radiologic reporting. At two major centers (Alberta Health Services-Calgary Zone and the Ottawa Hospital), all sinus CT scans performed over a 2-year period were identified (9,739), and 100 from each center were randomly selected for analysis. The radiology reports were scrutinized to determine if seven critical and 11 noncritical items were mentioned.

RESULTS

Many (22%) otolaryngologists are dissatisfied with current sinus CT radiologic reporting, and the majority (67%) would like more clinically useful information. All predefined sinus CT items were inconsistently reported. Anterior ethmoid artery anatomy, ethmoid skull base integrity, and sphenoethmoidal cell were the most infrequently reported critical items.

CONCLUSIONS

This study has demonstrated that important information is inconsistently reported for sinus CT, and most otolaryngologists would like to see more clinically relevant content in radiology reports. Optimizing the reporting of sinus CT scans will improve communication between the radiologist and other clinicians managing patients with sinonasal disease.

LEVEL OF EVIDENCE

2b.

Occurrence of maxillary sinus abnormalities detected by cone beam CT in asymptomatic patients

Background

Although cone beam computed tomography (CBCT) images of the maxillofacial region allow the inspection of the entire volume of the maxillary sinus (MS), identifying anatomic variations and abnormalities in the image volume, this is frequently neglected by oral radiologists when interpreting images of areas at a distance from the dentoalveolar region, such as the full anatomical aspect of the MS. The aim of this study was to investigate maxillary sinus abnormalities in asymptomatic patients by using CBCT.

Methods

1113 CBCT were evaluated by two examiners and identification of abnormalities, the presence of periapical lesions and proximity to the lower sinus wall were recorded. Data were analyzed using descriptive statistics, chi-square tests and Kappa statistics.

Results

Abnormalities were diagnosed in 68.2% of cases (kappa = 0.83). There was a significant difference between genders (p < 0.001) and there was no difference in age groups. Mucosal thickening was the most prevalent abnormality (66%), followed by retention cysts (10.1%) and opacification (7.8%). No association was observed between the proximity of periapical lesions and the presence and type of inflammatory abnormalities (p = 0.124).

Conclusions

Abnormalities in maxillary sinus emphasizes how important it is for the dentomaxillofacial radiologist to undertake an interpretation of the whole volume of CBCT images.

Cone-beam computerized tomography imaging and analysis of the upper airway: a systematic review of the literature

A systematic review of the literature concerning upper airway imaging and analysis using cone-beam computed tomography (CBCT) was performed. A PubMed search (National Library of Medicine, NCBI; revised 9th January 2011) yielded 382 papers published between 1968 and 2010. The 382 full papers were screened in detail. 46 articles were considered clinically or technically relevant and were included in this systematic review. These were classified as articles on accuracy and reliability of CBCT imaging of the upper airway (n=4), accuracy and reliability of DICOM viewers (n=2), synopsis (n=10), technical (n=7) and clinical applications (n=27). When one paper was considered related to two or more categories, it was assigned to each relevant group. Results indicate that three-dimensional (3D) analysis of the upper airway using CBCT can be achieved in an accurate and reliable manner. Important obstacles still need to be addressed, including the impact of respiration phase, influence of tongue position and mandible morphology, longitudinal and cross-sectional 3D CBCT upper airway evaluation, and 3D CBCT definition of the anatomical boundaries of the upper airway.

Modern dental imaging: a review of the current technology and clinical applications in dental practice

A review of modern imaging techniques commonly used in dental practice and their clinical applications is presented. The current dental examinations consist of intraoral imaging with digital indirect and direct receptors, while extraoral imaging is divided into traditional tomographic/panoramic imaging and the more recently introduced cone beam computed tomography. Applications, limitations and current trends of these dental "in-office" radiographic techniques are discussed.