Current Trends in Sinonasal Imaging

Imaging of the Sinonasal Cavities

This article describes the various abnormalities that affect the sinonasal cavities and discusses inflammations, tumors, and tumor-like conditions. Specific imaging evaluations that focus on the sinonasal cavities are described in more detail.

Adverse Events Associated With Image-Guided Sinus Navigation in Endoscopic Sinus Surgery: A MAUDE Database Analysis

OBJECTIVE

The utilization of image-guided navigation during endoscopic sinus surgery (ESS) has increased significantly since its introduction. However, the most common associated complications are still unknown. This study describes and analyzes adverse events related to image-guided ESS.

STUDY DESIGN

Cross-sectional analysis.

SETTING

The Food and Drug Administration's 2018-2022 MAUDE database (Manufacturer and User Facility Device Experience).

METHODS

The MAUDE database was searched for all reports on adverse events involving sinus navigation systems used in ESS from 2018 to 2022. Reported events were reviewed and categorized.

RESULTS

During the study period, there were 1857 adverse events from 1565 reports, which were divided into device-related (n = 1834, 98.8%) and patient-related (n = 23, 1.2%) complications. The most common device-related complications were nonfunctionality of the system (n = 512, 27.9%), device imprecision (n = 427, 23.3%), and device sensing problems (n = 277, 15.1%). The most common patient-related complications were cerebrospinal fluid (CSF) leak (n = 14, 60.9%), intracranial injury (n = 4, 17.4%), and bleeding/hemorrhage (n = 3, 13.1%). Imprecision was associated with increased risk of navigation abortion by the surgeon (odds ratio, 1.50 [95% CI, 1.38-1.65]; P < .001) and increased risk of CSF leak (odds ratio, 16.5 [95% CI, 3.66-74.0]; P < .001) as compared with other device-related complications.

CONCLUSIONS

The most commonly reported device- and patient-related adverse events associated with image-guided sinus navigation systems were device nonfunction, imprecision, device sensing difficulties, and CSF leak. When imprecise navigation occurred, there was an increased likelihood of CSF leak and navigation abortion by the surgeon. Health care providers should be mindful of these possible complications when electing to use image-guided sinus navigation during ESS.

Image guided dilation of sinus ostium in revision sinus surgery

PURPOSE

Assess if a rigid, image-guided balloon could be used effectively and safely in revision sinus surgery.

MATERIALS AND METHODS

A prospective, non-randomized, single-arm, multicenter study to assess the safety and device performance of the NuVent™ EM Balloon Sinus Dilation System. Adults with CRS in need of revision sinus surgery were enrolled for balloon sinus dilation of a frontal, sphenoid, or maxillary sinus. The primary device performance endpoint was the ability of the device to (1) navigate to; and (2) dilate tissue in subjects with scarred, granulated, or previously surgically-altered tissue (revision). Safety outcomes included the assessment of any operative adverse events (AEs) directly attributable to the device or for which direct cause could not be determined. A follow-up endoscopy was conducted at 14 days post-treatment for assessment of any AEs. Performance outcomes included the surgeon's ability to reach the target sinus (es) and dilate the ostia. Endoscopic photos were captured for each treated sinus pre- and post-dilation.

RESULTS

At 6 US clinical sites, 51 subjects were enrolled; 1 subject withdrew before treatment due to a cardiac complication from anesthesia. 121 sinuses were treated in 50 subjects. The device performed as expected in 100 % of the 121 treated sinuses, with investigators able to navigate to the treatment area and dilate the sinus ostium without difficulty. Ten AEs were seen in 9 subjects, with 0 related to the device.

CONCLUSION

The targeted frontal, maxillary or sphenoid sinus ostium were safely dilated in every revision subject treated, with no AEs directly attributed to the device.

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.

Preoperative Sinonasal Computed Tomography Score in Chronic Rhinosinusitis with Nasal Polyps

This study investigated the relationship between sinonasal inflammatory involvement according to the computed tomography (CT) staging system (Lund–Mackay score) with clinical, laboratory, histopathological and prognostic features of chronic rhinosinusitis with nasal polyps (CRSwNP). Seventy-eight patients with CRSwNP who had undergone surgery were enrolled. Total (p = 0.0062), ethmoid (p = 0.0496), sphenoid (p = 0.0335), ostiomeatal complex (OMC) (p = 0.0235) and frontal (p = 0.0164) CT scores were predictive of non-steroidal anti-inflammatory drugs-exacerbated respiratory disease (NERD) in the univariate analysis. Total (p = 0.0022), ethmoid (p = 0.0290), sphenoid (p = 0.0370), frontal (p = 0.0116), maxillary (p = 0.0357) and OMC (p = 0.0058) CT scores were predictve of asthma at the univariate analysis. No significant differences were found between patients with vs. without allergy in terms of total and partial CT scores. High blood eosinophil counts (>0.24 vs. ≤0.24 cells × 109/L) resulted in being associated with total (p = 0.0213), maxillary (p = 0.0227) and ethmoid (p = 0.0491) CT scores in the univariate analysis. Higher ethmoid (p = 0.0006) and total sinonasal (p = 0.0027) CT scores were found to predict histopathologically eosinophil CRSwNPs in the univariate analysis. CT scores did not result as predictive of NSAID-exacerbated respiratory disease, asthma, or blood eosinophil count at the multivariate analysis. Risk of relapse was related to the presence of NERD (p = 0.0207, HR [95% CI] 3.914 [1.232–12.435]), higher preoperative total (HR = 1.098 95%CI: 1.001–1.204, p = 0.0486) and frontal sinus CT scores (HR = 1.555 95%CI: 1.006–1.886, p = 0.0218), but these results were not confirmed by the multivariable analysis. Sinonasal CT scores showed significant differences in this heterogeneous inflammatory condition. Identifying CRSwNP characteristics is necessary to avoid generic treatments with poor outcomes.

The evolution of sinus surgery in England in the last decade - An observational study

Background and objective

Sinus surgery has seen significant changes over the years with advancements in instruments, endoscopes and imaging. This study aimed to use Hospital Episode Statistics (HES) data to review the total number of sinus related procedures performed in both adults and children across England and identify whether there were any trends across the study period. We predicted an increase in endoscopic sinus procedures with a decline in open approaches to the paranasal sinuses.

Methods

Data from HES was extracted for the years 2010–2019. The operative (OPCS-4) codes relevant to all sinus procedures between E12.1 and E17.9 were analysed. After examination of overall sinus related procedures, further subgroup analysis was performed with regards to open or endoscopic techniques.

Results

The total number of sinus procedures performed between 2010 and 2019 was 89,495. There was an increase in endoscopic surgeries by 21.1% and a decrease of open surgeries 35.3% during this time. There was an overall increase in maxillary, frontal and sphenoid sinus procedures, with a decrease in ethmoid sinus and lateral rhinotomy operations. There was an increase in the proportion of endoscopic cases overall by 5.7% and for all sinuses individually.

Conclusion

Overall, we see an increase in sinus surgery over the last 9 years from 2010 to 2019. These findings are in keeping with our initial hypotheses. Although our data set is limited by coding, and lack of patient factors, it represents most, if not all, of the data in England over a large study period. It is therefore useful to add to previous studies when demonstrating the increasing popularity of endoscopic sinus surgery over open procedures.

Footsteps of the Innovations in Rhinology

Rhinology is the study of nose, paranasal sinus, and nasopharynx. The nose is the most prominent structure on the human face and has been a subject of study since ancient human civilization. The history of rhinology has reflected the sociocultural aspects of the times, and rhinology has achieved remarkable growth with innovative discoveries by numerous pioneers. The focus of surgical procedures of the paranasal sinus shifted from mucosal stripping to functional endoscopic surgery with advancement of technology. Furthermore, the field of rhinology is gradually expanding due to cutting-edge technologies such as image-guided surgery, three-dimensional endoscopy, and robotic surgery. Additional clinical experiences and technological developments are expected to further advance rhinology.

Updates in techniques for improved visualization in sinus surgery

PURPOSE OF REVIEW

Adequate visualization during endoscopic sinus surgery (ESS) is one of the most critical aspects of performing well tolerated and successful surgery. The topic of visualization encompasses a broad spectrum of preoperative and intraoperative manoeuvres the surgeon can perform that aid in the understanding of the patient's anatomy and in the delivery of efficient surgical care.

RECENT FINDINGS

Preoperative considerations to improve visualization include optimization of haemostasis through management of comorbidities (e.g. hypertension, coagulopathies), medication management (e.g. blood thinners) and systemic versus topical corticosteroids. New technologies allow preoperative visual mapping of surgical plans. Advances in knowledge of intraoperative anaesthesia have encouraged a move toward noninhaled anaesthetics to reduce bleeding. High definition cameras, angled endoscopes, 3D endoscopes and more recently augmented reality, image-guided surgery, and robotic surgery, represent the state of the art for high-quality visualization. Topical interventions, such as epinephrine, tranexamic acid and warm isotonic saline, can help to reduce bleeding and improve the operative field. Surgical manoeuvres, such as polyp debulking, septoplasty, carefully controlled tissue manipulation and a consistent repeatable approach remain fundamental to appropriate intraoperative surgical visualization.

SUMMARY

This chapter delineates medical, technical and technological means - preoperatively and intraoperatively - to achieve optimized visualization of the surgical field in ESS.

Image optimization and reduction of radiation dose in CT of the paranasal sinuses

INTRODUCTION

Due to use of ionization radiation in the computed tomography (CT), optimal parameters should be used to reduce the risk of incidence of secondary cancers in patients who are constantly exposed to x-rays. To reduce the dose delivered to patients in each scan, CT technologists can change the image acquisition parameters. However, this reduces image quality. The present study aimed to optimize and reduce radiation dose in a CT of the paranasal sinuses while minimizing deterioration of image quality.

METHODS

In this study patients were divided in two groups: Group A was scanned axially and coronally using default parameters, while Group B was scanned axially and coronally using new parameters. Common CT dose descriptors including weighted computed tomography dose index (CTDIw), volumetric CTDI (CTDIvol), dose length product (DLP), effective dose (ED) and image noise were measured for each group. The patients' organ doses were estimated using the ImPACT CT patient Dosimetry Calculator. The tube voltage, tube current, pitch, rotation time, and other parameters were then reduced and optimized. After reconstruction and analysis, all of the images were of good diagnostic quality in both groups Results: Using the new parameters, good agreement was found between the direct and reconstructed images. The CT parameters were reduced by the following proportions: kVp-16.6%, mA-75%, rotation time-20%, and mAs-80%. However, these reductions did not obscure any anatomical landmarks. These parameters reduced the CTDIw, CTDIvol and DLP by 88.2%, 91.3%, and 91.3% respectively.

CONCLUSION

The results suggest that the use of a Bone algorithm reduces the total amount of radiation used during CT of the sinuses. We recommend using these parameters in children, in the evaluation of facial trauma, and in emergency CT of the paranasal sinuses.

Intraoral Herniation of a Sinonasal Polyp: An Underreported Complication of Maxillary Extraction?

PURPOSE

The aim of the present study was to increase awareness of an underreported surgical complication by presenting the relevant findings of cases of herniated oroantral sinonasal polyp (OASNP) identified from our biopsy service and from previously reported cases.

MATERIALS AND METHODS

The present study was a retrospective descriptive case series with a review of the reported data. Cases of OASNP were identified from our biopsy service, and the clinical, radiographic, surgical, and demographic information was retrieved. Previously reported cases of OASNP were also reviewed.

RESULTS

We identified 14 cases of OASNP in our biopsy service and an additional 10 reported cases. Overall, OASNP was more prevalent in males (71%). The age range was 19 to 85 years (overall mean, 46.6 years; median, 43.5 years). OASNP typically presented as a red polypoid mass that was frequently pedunculated with a smooth or granular surface. The lesions were located on the maxillary alveolus in the molar region. The most commonly implicated tooth was a maxillary first molar (74%). In some cases, the OASNP had been mistaken for a tumor or pyogenic granuloma. Almost all were at least 1 cm in the greatest dimension, with 43% measuring at least 2 cm in size, and 1 lesion reaching 5 cm in diameter. The reported period for development of the lesion ranged from 2 days to 5 years, with 60% developing within 2 months of the extraction. All lesions had undergone surgical excision. Antibiotic use and surgical closure of the oroantral communication had been described for some of the cases.

CONCLUSIONS

The results from our study suggest that herniation of a sinonasal polyp through an oroantral defect could be an underreported complication of maxillary exodontia. Additional research would help to enhance our knowledge and understanding of this interesting condition.

Nasal saline irrigation - A review of current anatomical, clinical and computational modelling approaches

Nasal saline irrigation is frequently utilised in allergic rhinitis and rhinosinusitis management, and after nasal and sinus surgery. Anatomical modelling, clinical and computational studies guide treatment optimisation. This review offers a comprehensive summary of the modelling methodologies used in previous nasal irrigation studies by undertaking a systematic analysis of anatomical, clinical and computational investigations that assessed nasal saline irrigation using Medline, EMBASE, and Cochrane Review databases. Both procedural and assessment methods were reviewed. It was found that all twenty-four publications reviewed did not discuss the influence of the nasal cycle on internasal geometry and nasal resistance. Cadaver studies misrepresent in vivo nasal geometry. Irrigation pressure and shear forces, which could influence mucociliary transport and postoperative cleaning, were not evaluated. Previous studies focus on irrigation coverage and have not considered the nasal cycle which influences unilateral nasal resistance and thus pressure/ flow relationships and may also increase nasal air-locking. New computational fluid dynamic models could better inform nasal irrigation clinical practice.

Role of diffusion-weighted imaging in the discrimination of purulent intrasinusal content: A retrospective study

OBJECTIVES

The objective of this study was to analyse MRI with morphological (T1, T2) and diffusion sequences (DWI, b1000) in patients presenting non-aggressive patterns of sinus opacity and operated on by functional endoscopic sinus surgery (FESS).

DESIGN

A retrospective study.

SETTING

Diffusion imaging in paranasal sinus pathology remains little known. To date, no imaging system is capable of determining the purulent content of a non-enhanced sinus filling.

PARTICIPANTS

We included consecutive patients having undergone FESS in whom MRI of the paranasal sinuses was performed. Subjects were allocated to Case (pus) or Control (no pus) groups depending on sinus content found intraoperatively. FESS was performed for bacterial acute rhinosinusitis, acute exacerbations of chronic rhinosinusitis, non-purulent sinusitis, naso-sinusal polyposis, antrochoanal polyp, isolated polyp, angiomatous polyp and eosinophilic fungal sinusitis. Tumours, mucoceles and fungus balls were excluded.

MAIN OUTCOME MEASURES

We analysed T1, T2, b1000 and MRI sequences and ADC map.

RESULTS

On univariate analysis, intermediate signal in T2 and high signal in b1000 were associated with Cases (P < 0.001) as were low ADC values (P < 0.001). The difference in mean ADC values between Cases and Controls was statistically significant (respectively, 0.518 vs 2.041 × 10^-3  mm² /sec, P < 0.01). On multivariate analysis, MRI with ADC < 0.725 × 10^-3  mm² /sec and b1000_SI > brain was significantly associated with the case group. MRI with b1000_SI < brain and ADC > 1.450 × 10^-3  mm² /sec was significantly associated with the control group.

CONCLUSIONS

Diffusion MRI offers extremely promising results regarding content characterisation of infectious sinus diseases.

Diffusion-Weighted Magnetic Resonance Imaging in Maxillary Sinuses Inflammatory Diseases: Report of Three Cases and Literature Review

Background

Magnetic resonance imaging is considered a preferable imaging examination in the diagnosis of inflammatory maxillary sinus disease and can provide precise sinonasal characterization. Diffusion-weighted magnetic resonance imaging and apparent diffusion coefficient are complementary magnetic resonance imaging tools that can be applied to the differentiation of sinus diseases. In this report, 3 cases of inflammatory maxillary sinus diseases imaging findings considering diffusion-weighted magnetic resonance imaging features were described. Additionally, a literature review considering the use of diffusion-weighted magnetic resonance imaging in inflammatory lesions is provided.

Methods

The cases reported were: presence of air-fluid levels, mucosal thickening and a mucous retention cyst. Conventional magnetic resonance imaging and apparent diffusion coefficient (ADC) maps, with ADC values were demonstrated. In the literature review, the studies considering inflammatory lesions were detailed, as well as ADC values established by investigators.

Results

ADC values for presence of air-fluid levels, mucosal thickening and mucous retention cyst were respectively: 1.99 x 10^-3 mm²/s; 1.83 x 10^-3 mm²/s; 2.05 x 10^-3 mm²/s.

Conclusions

It was observed that apparent diffusion coefficient values from the inflammatory lesions described in this report were different and apparent diffusion coefficient may be useful in the differentiation of these maxillary sinus alterations. Further larger sample investigations considering apparent diffusion coefficient values focusing in inflammatory lesions are recommended. The lack of studies considering the use of diffusion-weighted magnetic resonance imaging on inflammatory diseases diagnostic was the major limitation to the literature review.

[Imaging of the paranasal sinuses and anterior skull base]

Due to the complex anatomy of the anterior skull base and paranasal sinuses, radiologic diagnostics in this area are challenging. Magnetic resonance imaging (MRI) and computed tomography (CT) are the primary indicated modalities. Guidelines helping to select the appropriate modality have been published by the German Society of Head and Neck Radiology and the Society of Otorhinolaryngology. The present article presents an overview of the current radiologic procedures and their optimized implementation using clinical examples. These examples highlight the fact that a combination of at least CT and MRI is frequently required. Use of CT for intraoperative navigation is everyday practice in clinical routine. Occasionally, additional procedures such as angiography or myelography are necessary, particularly in cases of preoperative vascular diagnostics or embolization. Overall, evaluation of radiologic diagnostics in this area is complex; it requires experience and knowledge of the disease, as well as an understanding of the diagnostic procedures. Close collaboration between head and neck surgeons and radiologists is thus essential.

Clinical efficacy of main radiological diagnostic methods for odontogenic maxillary sinusitis

The objective of the study was to compare the ability of dental, ENT and radiology specialists to identify the dental cause of maxillary sinusitis with conventional computed tomography, dental and panoramic radiographs. Out of 34 dental records from subjects treated at ENT and Oral and Maxillofacial Surgery Department, LUHS Kaunas Clinics, 22 females and 12 males with the diagnosis of odontogenic maxillary sinusitis, periapical (DPA), panoramic (DPR) and computed tomography (CT) images of posterior maxilla were selected for further studies. In total, 39 sinuses with an odontogenic and 37 sinuses with only rhinogenic cause (control group) were included in the study. Sinuses with mucosal thickening less than 3 mm were excluded from the research. Each image was evaluated by 5 endodontologists, 5 oral surgeons, 6 general dentists, 6 otorhinolaryngologists and an experienced oral radiologist. DPR and DPA views were not evaluated by ENT specialists. The dental cause of maxillary sinusitis was marked according to the given scale. Intraclass correlation coefficient and ROC curve statistical analysis were performed. The best accuracy was observed when CT views were evaluated by experienced oral radiologist and oral surgeons: the AUC was 0.958 and 0.859, respectively. DPR views showed the best accuracy when evaluated by oral surgeons (0.763) and DPA-by endodontologists (0.736). The highest inter-rater agreement was observed between experienced oral radiologist and oral surgeons/otorhinolaryngologists (0.87/0.78) evaluating CT. Sensitivity and specificity of CT were 89.7 and 94.6%, DPR-68.2 and 77.3%, DPA-77.9 and 67%. Identification of dental cause of maxillary sinusitis sometimes is a challenge, which depends on radiological method and, more importantly, on evaluator's experience.

Thirty years of endoscopic sinus surgery: What have we learned?

Prior to adaptation of endoscopic approaches for sinonasal pathology, patients regularly endured significant morbidity from open approaches to the sinonasal cavity that were often fraught with failure. With improvements in transnasal endoscopy, functional endoscopic sinus surgery subsequently emerged from the work of Messerklinger and other pioneers in the field. The popularity of endoscopic sinus surgery quickly escalated and expanded to pathology other than inflammation. Here, we discuss the evolution of endoscopic sinus surgery as it relates to improvements in understanding disease pathogenesis, improvements in instrumentation and expansion of indications.