Paranasal Research Articles

The primary systemic vasculitis associated optic neuritis: a retrospective analysis in a single center over 10 years

ObjectivesTo investigate the clinical and image characteristics of primary systemic vasculitis-associated optic neuritis patients.MethodsThis is a retrospective study. The patients clinically diagnosed with primary system vasculitis-induced optic neuritis were recruited from March 2013 to December 2023. All cases received orbital magnetic resonance imaging scans were analyzed. The ocular findings, systemic manifestations, laboratory data and prognosis were reviewed retrospectively. In addition, the related literature was reviewed.ResultsFourteen patients (21 eyes), including 10 men and 4 women, were enrolled in this study. The ages ranged from 30 to 86 years in this cohort. Orbits MRI detects the enlargement and/or enhancement of the optic nerve. Cases 1–5 reported a confirmed diagnosis of Takayasu’s arteritis, and cases 6–8 had giant cell arteritis. Cases 9–13 were antineutrophil cytoplasmic antibody-associated vasculitis. Case 14 was Cogan’s syndrome. Mult organs and tissues, such as the kidneys, heart, paranasal sinuses, meninges, and respiratory system, were involved. In all of the 14 involved patients, the disease onset was either during the fall or winter season. There were no or only slight improvements in visual activity after conventional therapies.ConclusionsThe autoantibodies’ attack on the optic nerve, ischemic damage, or destruction of the blood–brain barrier may be the potential pathogenesis of vasculitis-associated optic neuritis. Even with prompt and aggressive clinical interventions, the prognosis remains unsatisfactory.

A novel technique for skull base reconstruction in craniofacial fibrous dysplasia surgery using three-dimensional printing and a dental alginate mold: illustrative case.

Fibrous dysplasia is a rare and benign skeletal lesion characterized by fibrous tissue proliferation due to an abnormal osteogenesis replacing normal bone. An 18-year-old male with fibrous dysplasia of the left sphenoid, ethmoid, orbit, and frontal bones was managed with excision and skull base reconstruction. After complete removal of the tumor, skull base reconstruction was commenced by making a reverse temporalis flap and placing it over the opened paranasal sinuses for a robust vascularized graft, followed by an abdominal fat graft, and then a pedicled pericranal flap was added to complete the multilayer onlay graft. To recreate the skull base, a mirror image of the contralateral skull base was constructed using three-dimensional (3D) printing, and the 3D-printed model was sterilized prior to the surgery. Intraoperatively, the model was then pressed onto dental alginate gel to make a negative mold. This was used to make the definitive flap using polymethylmethacrylate. Temporoplasty was also performed using polymethylmethacrylate to fill the defect left by the temporalis graft. The patient recovered well following the procedure. Appropriate, personalized skull base reconstruction techniques can be successfully done with 3D printing using alternative low-cost materials and implements, especially following resection of cases like craniofacial fibrous dysplasia. https://thejns.org/doi/10.3171/CASE24262.

Evaluation of the pharmacokinetics of an experimental combined form of IFNα and IFNγ for intranasal use

Polypous rhinosinusitis is a chronic inflammatory disease of the nasal mucosa and paranasal sinuses. Recombinant interferon has antiproliferative activity and corrects the deficiency of endogenous regulatory molecules, which allows us to consider this class of immunotropic drugs as a promising component of conservative immunotherapy for polyposis rhinosinusitis. Purpose of the study: To select the optimal composition of the experimental composition of interferons and evaluate their pharmacokinetic parameters in laboratory animals.For laboratory evaluation of the effectiveness of the auxiliary components of the proposed composition in creating a local effect, Wistar rats in the amount of 30 animals were selected, to which the proposed form of the drug (IFN1) was administered once intranasally. The control group included 30 animals that were alternately administered intranasally with a similar dose of IFNα2b and IFNγ dissolved in water for injection (IFN2). Quantitative determination of interferon concentration in blood samples was carried out using the enzyme immunoassay method. To assess the dependence of changes in concentrations in the blood of animals on the time elapsed after their administration, standard pharmacokinetic models were used. Next, the integral from the initial moment of time to infinity was determined, which corresponded to the area under the pharmacokinetic curve and made it possible to calculate a number of pharmacokinetic characteristics.The following indicators were obtained: 1) Area under the pharmacokinetic curve (AUCt) ng/ml/min – IFN1 = 683.0; IFN2 = 1707.7. 2) Absorption constant (Kp) – IFN1 = 0.13096; IFN2 = 0.03836. 3) Suction constant (Kel) – IFN1 = 0.00177; IFN2 = 0.00317. 4) Clearance (Cl) ml/min – IFN1 = 129.35; IFN2 = 51.73.Based on the differences in the values of pharmacokinetic parameters (AUCt) for the IFN1 and IFN2 preparations, it can be concluded that the use of a composition based on chitosan, succinic acid and DMSO leads to a pronounced retention of interferon in the nasal mucosa, which provides a pronounced local therapeutic effect and allows for fewer systemic adverse reactions. This composition is suitable for further clinical studies of the effectiveness of immunotherapy for polyposis rhinosinusitis.

The Diagnosis and Treatment of Chronic Rhinosinusitis.

Chronic rhinosinusitis (CRS) is a heterogeneous condition characterized by local chronic inflammation of the mucous membranes of the nose and paranasal sinuses. It affects approximately 5% of the population. This review is based on relevant publications retrieved by a selective search of the literature, with particular attention to current national and international guidelines. CRS is defined by, and diagnosed on the basis of, a combination of symptoms and objective findings of nasal endoscopy and imaging studies. It markedly impairs quality of life and gives rise to both direct and indirect health care costs. In 20-45% of cases, CRS is associated with comorbid bronchial asthma and a significantly elevated risk of further diseases (e.g., COPD, OR 1.73; depression, HR 1.50; obstructive sleep apnea, OR 1.91; carcinoma, OR 1.14-5.30). CRS is primarily treated medically with topical steroids (standardized mean difference of nasal symptoms, -0.63 (95% confidence interval [-0.89; -0.37]; standardized mean difference of quality of life as measured by SNOT -22, -5.46 [-8.08; -2.84]), as well as with nasal lavage and, as an option, systemic steroids (and antibiotics where appropriate). If appropriate medical treatment fails to bring about adequate and sustained improvement, endoscopic surgery on the paranasal sinuses is indicated. This improves the individual symptoms, the overall symptom score, and patients' quality of life. Severe refractory CRS with nasal polyposis can be treated with biological agents. CRS calls for individually adapted medical and/or surgical treatment.

A mini-update on chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is an inflammatory disorder of the paranasal sinuses and the nasal cavity lasting longer than 12 weeks. This disease is a common clinical syndrome with significant monetary burden due to the high costs of medical visits, diagnostic tests, medications, and surgical therapies. CRS without nasal polyposis (CRSsNP) is the most common subtype of CRS, accounting for about 70% of all patients. Other subtypes include CRS with nasal polyposis (CRSwNP) and allergic fungal rhinosinusitis (AFRS). CRSwNP has the worldwide prevalence of 2% to 4% and is often accompanied by type 2 inflammation and asthma as a comorbid condition. Pediatric chronic sinusitis is distinct from adult chronic sinusitis and is currently considered an infectious process, characterized by persistent inflammation representing an exaggerated immune response to an external stimulus. The medical and surgical management of CRS has been remarkably modified in the past two decades. The aim of this study was to present an update on CRS based on the recent years’ literature.

Computed tomographic findings of nasal and paranasal disease in domestic rabbits highlight maxillary sinusitis and close association with dental disease: 100 studies (2004-2024).

To describe CT findings and epidemiologic features of nasal and paranasal disease of rabbits (Oryctolagus cuniculus). An electronic search was performed for rabbits that underwent skull CT from 2004 to 2024 and had findings consistent with nasal/paranasal or maxillary dental disease. History, signalment, and physical examination findings were recorded and reevaluated retrospectively for evidence of changes to the nasal passages, paranasal sinuses, and nearby associated anatomy. Data were analyzed with descriptive statistics, ordinal mixed logistic regression, and correlation analysis. 100 studies from 69 rabbits were reviewed. Lop-eared rabbits represented 30 of 69 cases. Upper respiratory signs (48 of 69 [69.6%]) and dental-related disorders (21 of 69 [31.9%]) were primary complaints. Rhinitis (49 of 69 [71.0%]), sinusitis (50 of 69 [72.5%]), and both (40 of 69 [60.0%]) were most diagnosed, with turbinate destruction (48 of 69 [69.6%]) and alveolar bone loss of adjacent teeth (51 of 69 [73.9%]) being common findings. Sinusitis was most common in the ventral (48 of 50 [96.0%]) and dorsal (33 of 50 [66.0%]) recesses of the maxillary sinus. Multiple CT variables were significantly correlated (P < .05); of those, maxillary alveolar bone loss of the incisor teeth and the second premolar tooth were, respectively, correlated with rhinitis grade and with sinusitis and sinusitis grade within the ventral recess of the maxillary sinus (P < .001). Computed tomographic evaluation allowed characterization of nasal and paranasal disease in rabbits and the association of rhinitis, sinusitis, and dental disease. The correlation between the maxillary dentition, rhinitis, and sinusitis highlights the need for thorough evaluation in CT of the teeth in rabbits with upper respiratory signs.

Primary Ewing Sarcoma in the Sphenoidal Sinus: A Case Report.

Ewing's sarcoma (EWS) is a rare malignant bone tumor that primarily affects children and young adults. While it typically affects long bones, it can occur in the head and neck region, including the paranasal sinuses in rare cases. We present a challenging case of a 45-year-old female diagnosed with an EWS of the sphenoidal and the right nasal fossa. A subtotal removal of the mass was performed on the patient followed by combined adjuvant radiotherapy and chemotherapy. Due to its rarity, the diagnosis and management of EWS in the paranasal sinuses are challenging.

Prevalence of pneumatisation patterns of Onodi cells among the North-East Indian population

BackgroundThe posterior ethmoid sinuses have a complex anatomy and a highly variable normal structure. The posterior ethmoid Onodi cell needs careful assessment because of its proximity to the optic nerve and the internal carotid artery canal. Recognising the distinctions is essential for optimal pre-op preparation. Sphenoid sinus surgery can now be performed without worrying about compromising vital structures like the internal carotid artery or optic nerve. Preoperative radiological assessment is a quick and easy way to check for ethmoid cell pneumatisation differences.Aim and objectivesTo determine the pneumatisation patterns of Onodi cells among the North-East Indian population using 16-slice multidetector computed tomography (MDCT).ResultsNine-hundred MDCT paranasal sinuses were analysed over a period of 0–2 years, out of which 220 cases showed the presence of Onodi cell. Type I were 89 cases (40.45%, CI 32.00–48.90), Type II were 128 cases (58.18%, CI 49.72–66.63), and 3 cases with Type III cell (1.36%, CI 0.18–2.54).ConclusionThe most prevalent pneumatisation pattern is Type II. The pneumatisation patterns of Onodi cells can be best detected and evaluated by multiplanar MDCT imaging. Sinus surgeons need a firm grasp of pneumatisation patterns to avoid damaging the optic nerve and internal carotid artery canal during operations.

Microbiological profile and antibiotic susceptibility pattern of chronic dacryocystitis at a tertiary eye care centre in Western India

: Chronic dacryocystitis is a low-grade infection &amp; inflammation of the lacrimal sac. If neglected the infection may extend to surrounding orbit, brain and paranasal sinuses leading to sight and/or life-threatening complications. Thus appropriate, effective and timely antibiotic treatment/ prophylaxis is desirable. The present study was aimed to document the current microbiological profile and antibiotic susceptibility in adult patients of chronic dacryocystitis seen at our tertiary eye care centre in western India.The study was a cross-sectional, prospective, observational study. The study included 60 adult patients of chronic dacryocystitis. In every case two samples from the lacrimal sac collected via the regurgitation technique or by lacrimal passage syringing were sent for microbiological evaluation. Gram staining was used for identification of bacterial pathogen. KOH mount was used for identification of fungi. The second swab was used for performing culture -sensitivity. The Clinical and Laboratory Standard Institute Guidelines were used to know the antimicrobial sensitivity. Kirby-Bauer disk diffusion method was used for this purpose. The statistical analysis was done using descriptive statistics as mean, standard deviation, median and percentages. Microsoft excel worksheet was used. 60 samples were taken. 53/60 (88.3%) samples showed microbial isolates after 24-48 hours of incubation. 78.3% were gram positive organisms and 10% were gram negative organisms. The most common gram-positive organism was (68.3%) and the most common gram-negative organism was (8.3%). Amongst the antibiotics the most sensitive antibiotic was Ampicillin + Sulbactam (92.5%) and the most resistant antibiotic was Ciprofloxacin (3.8%). The antibiotic most sensitive to gram positive organisms was Ampicillin and Sulbactam, Cephalexin, Linezolid, Cloxacillin and Vancomycin. The antibiotic most sensitive to gram negative organisms was Gentamicin, Amikacin, Gatifloxacin, Ceftazidime, Meropenem and Polymixin -B. The current microbiological profile and antibiotic susceptibility of the microorganisms responsible for chronic dacryocystitis is an invaluable tool in the treatment of chronic dacryocystitis with the most appropriate and effective antibiotic.

Multivariate regression analysis of risk factors for the development of polyposisrhinosinusitis

Introduction. Chronic rhinosinusitis with nasal polyps is a group of chronic recurrent inflammatory diseases of the nasal mucosa and paranasal sinuses with an incompletely understood etiopathogenesis. Despite various theories on the development of this disease and principles of pathogenetic therapy, some patients continue to suffer from the disease, which is resistant to both medical and surgical treatment.The aim of this study was to identify the most significant risk factors for the development of polypoid rhinosinusitis in patients with chronic purulent rhinosinusitis using binary logistic regression.Materials and methods. The study included patients diagnosed with chronic purulent rhinosinusitis (n=40) and chronic purulent-polypoid rhinosinusitis (n=40) who were treated at the otorhinolaryngology department of the Chita Clinical Hospital "RZD-Medicine" from 2016 to 2020. The control group consisted of 20 healthy volunteers, matched by sex and age with the study groups. All subjects underwent comprehensive clinical examinations, bacteriological analysis, endoscopic examination, and measurements of interleukin (IL)-1β, IL-2, IL-4, IL-6, IL-8, IL-10, defensins (HAD 1-3), heat shock protein 70 (HSP70), and autoantibodies to it in serum and nasal secretions, as well as the coagulation activity of nasal secretions. Binary logistic regression was used to analyze risk factors for the development of polypoid rhinosinusitis.Results. We demonstrated that high predictive significance for the development of nasal mucosal polyps in patients with purulent rhinosinusitis is associated with concentrations of heat shock protein 70, IL-10, and HAD 1-3 in serum.Conclusion. A test set that includes levels of HSP70, IL-10, and HAD 1-3 in serum can predict the development of chronic polypoid rhinosinusitis with 99% accuracy.

Evolution of understanding the anatomy of the respiratory system

This article highlights the history of the development of the anatomy of the respiratory system. The preparation of this publication utilized articles from journals included in the Russian Science Citation Index (RSCI) and Pub- Med. The depth of the publication search spanned 20 years. The article summarizes knowledge about the development of ideas about the anatomy of the respiratory system. The first mentions of the respiratory organs—lungs, bronchi, trachea—date back to Ancient times. Scientists and physicians of that era attempted to determine the structure of the lungs. Not all medical schools associated breathing with the lungs. During the Renaissance, empirical knowledge in this field continued to accumulate. Autopsies allowed for more detailed descriptions of the chest structure, lungs, trachea, and bronchial system. The invention of the microscope in the 17th century enabled the study of lung structure down to the alveoli and capillaries. Various types of epithelial cells of the respiratory tract, nasal cavity sinuses, and more were described. In modern times, technologies have made it possible to obtain the first microphotographs showing the ultrastructure of the pulmonary capillary and the blood-gas barrier. The history of the development of the understanding of the anatomy of the respiratory system can be considered when studying specific topics within university courses such as "Human Anatomy," "History of Medicine," and "History of Biology."

Radiation dose reduction and image quality in pediatric paranasal sinus CT: with automatic tube current modulation and iterative reconstruction technique.

Our objective is to evaluate radiation dose and image quality in pediatric paranasal sinus computed tomography (CT) with automatic tube current modulation (ATCM) and sinogram-affirmed iterative reconstruction algorithm (SAFIRE). CT scans from 80 patients were divided into two groups: Group A [80 kVp, pitch 1.5, 40 mAs, the filtered back projection (FBP) algorithm] and Group B (70 kVp, pitch 3, ATCM with reference at 40 mAs, SAFIRE strengths 1-5). We have evaluated image quality and radiation dose. Group B demonstrated significantly lower volume computed tomography dose index, dose-length product, and effective dose than Group A (0.13±0.03 vs. 1.57±0.01mGy, 2.27±0.82 vs. 19.88±2.01mGy·cm, and 0.0081±0.0017 vs. 0.079±0.013mSv, respectively; P<.001). Increasing SAFIRE strengths correlated with noise reduction and SNR enhancement. Group B's noise and SNRsoft at SAFIRE strength 5 were comparable with Group A. Images reconstructed with SAFIRE strength 5 in Group B exhibit comparable image quality with FBP in Group A.

Revealing the surprising: Computed tomography-guided exploration of paranasal sinuses incidental findings

BackgroundIncidental findings (IFs) are unintentional discoveries that are unrelated to the original imaging goal. Imaging exams of persons with suspected intracranial disorders may reveal IFs in the paranasal sinuses (PNS). The current investigation aims to determine the frequency and features of unexpected discoveries in the PNS in persons who have had brain computed tomography (CT) scans for suspected intracranial abnormalities. MethodsBetween December 2022 and February 2023, 100 patients who met the inclusion criteria for clinically suspected intracranial disorders had CT brain scans as part of this retrospective cross-sectional study. Two board-certified radiologists with at least three years of experience assessed the CT scans independently. The study investigated the incidence and proportion of paranasal sinuses incidental findings (PNS IFs) observed during brain CT scans to detect brain abnormalities. ResultsThe study discovered that 27% of patients had IFs, with the retired population (aged 61 and up) having the highest prevalence, particularly among men. Acute sinusitis was the most commonly diagnosed incidental finding (IF), accounting for 15% of total cases. In addition, we found polyps, retention cysts, chronic sinusitis, mucoceles, and fungal infections. Left-sided maxillary sinus abnormalities outnumbered right-sided ones. Bilateral involvement was unusual. ConclusionThese findings emphasize the importance of addressing IFs in the PNS when treating patients, as they may necessitate further inspection or intervention. These results have the potential to help establish strategies for treating patients with incidental paranasal sinus findings, ultimately improving patient care.

Twistable and Stretchable Nasal Patch for Monitoring Sleep-Related Breathing Disorders Based on a Stacking Ensemble Learning Model.

Obstructive sleep apnea syndrome disrupts sleep, destroys the homeostasis of biological systems such as metabolism and the immune system, and reduces learning ability and memory. The existing polysomnography used to measure sleep disorders is executed in an unfamiliar environment, which may result in sleep patterns that are different from usual, reducing accuracy. This study reports a machine learning-based personalized twistable patch system that can simply measure obstructive sleep apnea syndrome in daily life. The stretchable patch attaches directly to the nose in an integrated form factor, detecting sleep-disordered breathing by simultaneously sensing microscopic vibrations and airflow in the nasal cavity and paranasal sinuses. The highly sensitive multichannel patch, which can detect airflow at the level of 0.1 m/s, has flexibility via a unique slit pattern and fabric layer. It has linearity with an R2 of 0.992 in the case of the amount of change according to its curvature. The stacking ensemble learning model predicted the degree of sleep-disordered breathing with an accuracy of 92.9%. The approach demonstrates high sleep disorder detection capacity and proactive visual notification. It is expected to help as a diagnostic platform for the early detection of chronic diseases such as cerebrovascular disease and diabetes.

Transnasal Endoscopic Approach for Excision of Intracranial Nasal Dermoid Sinus Cysts.

Nasal dermoid sinus cysts (NDSCs) with intracranial extension in the form of dermal sinus tracts require careful and complete resection to prevent recurrence. Resection techniques necessitate adequate intracranial exposure, but morbidity associated with historical resection approaches has presented unique multidisciplinary challenges for surgeons treating cysts with intracranial extension. The authors primarily employed a transnasal approach through a midline nasal incision, utilizing endoscopic or microscopic access between the lateral cartilages for resection of NDSCs with intracranial extension. A retrospective review was completed for patients treated for NDSCs at the authors' pediatric quaternary referral center from 2017 to 2023. Data collection included demographics, comorbidities, perioperative data, pre and postoperative imaging, surgical outcomes, and complications. Eighteen patients with NDSCs with possible or confirmed intracranial extension were surgically treated from 2017 to 2023. Fifteen were treated with resection performed through a midline transnasal approach with endoscopic assistance, achieving successful total resection while avoiding nasal osteotomy or frontal craniotomy. One patient had a slow cerebrospinal fluid leak from an operative durotomy, successfully treated with a lumbar drain. No other complications occurred. No patients required transfusion. Incision length and postoperative scar burden were less than approaches that used osteotomies or craniotomies and demonstrated excellent cosmetic results. No patients have had cyst recurrence or required reoperation. A transnasal approach through a midline incision with endoscopic assistance is an effective approach for resection of NDSC with intracranial extension, but utility may vary with cyst size and complexity. This approach leverages appropriate exposure for resection with decreased morbidity and decreased incision length through avoidance of osteotomies.

Initial Frontal Sinus and Orbit Tumor Signaling Late Distant Metastasis in Kidney Cancer.

Although metastases to the paranasal sinuses are exceedingly rare, when they do occur, renal clear cell carcinoma is the most frequent primary tumor involved. The aim of this work was to present a case of metastatic clear cell renal carcinoma in the frontal sinus and orbit region, 7 years after the initial diagnosis and treatment. The patient was referred to our clinic due to drooping of the left eyelid and displacement of the left eyeball. Computed tomography revealed an expansive lesion in the left frontal sinus and orbit, causing destruction of its anterior, lateral, and roof walls. Profuse bleeding from the tumor and left orbit hindered a comprehensive assessment of tumor extension into the orbit and residual tumor size. Therefore, complete tumor removal was not possible; instead, reduction was achieved. Subsequent histopathologic and immunohistochemical analysis confirmed the lesion as a metastasis of renal cell carcinoma in the sinonasal tract. Unfortunately, 10 weeks later, the patient passed away. Treatment of metastatic clear cell renal carcinoma depends on the localization of the disease as well as the overall condition of the patient. If there is a solitary metastatic lesion, as in the case of the sinonasal region, surgical treatment is recommended. Metastasis of clear cell renal carcinoma to the sinonasal region is a rare occurrence; however, it is essential to consider it in cases of rapidly growing tumor masses, typically presenting with symptoms such as epistaxis and nasal obstruction.

Fungal Infections of the Paranasal Sinuses: Microbiological Profiles and Treatment Outcomes

Fungal Infections of the Paranasal Sinuses: Microbiological Profiles and Treatment Outcomes

Recurrent Frontal Sinus Mucocle—A Novel Management Approach

A mucocele, or collection of mucoid secretion and desquamated epithelium within a paranasal sinus with distension of its walls, is considered a destructive lesion that resembles an expansile cyst. It can erode bone and therefore may extend in to the orbit or the cranium. The frontal sinus experiences the majority incidence, followed by the ethmoid sinus. This case of frontal sinus mucocele presented 8 years after an event of blunt trauma. The individual presented with a nonresolving right frontal head ache, proptosis of right eye and diplopia for the past 6 weeks. This case report emphasizes on the management of a large, chronic mucocele with prompt resolution of signs and symptoms.

A case of diffused large B-cell lymphoma in an elderly patient successfully treated with R-mini-CHOP

Diffuse large B-cell lymphoma (DLBCL) is a diverse group of B-cell lymphomas that vary in their clinical characteristics. Usually manifesting as a rapidly progressing or advanced condition, it is often curable even at advanced stages. The illness originates in extranodal and extramedullary tissues in 40% of patients. Patients over the age of 80 who have comorbidities or fragile conditions may be eligible for Rituximab and Reduced Dose CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) (R-mini-CHOP) chemoimmunotherapy. We report a 75-year-old woman with a tumor on the right side of the nose that covers the eye, so it is easy to fall out. The diagnosis of DLBCL (sinonasal) was made on the basis of computed tomography (CT) scan of the paranasal sinuses with contrast and immunohistochemical examination. Due to the age of the patient, who was included in the very elderly category with moderate frailty based on instrumental activities of daily living (IADLs), the patient was given R-mini-CHOP chemoimmunotherapy for six cycles, followed by radiation as much as 20 × 18 Gray (Gy) where the patient in the final evaluation stated complete response.

The Bony Nasal Cavity and Paranasal Sinuses of Big Felids and Domestic Cat: A Study Using Anatomical Techniques, Computed Tomographic Images Reconstructed in Maximum-Intensity Projection, Volume Rendering and 3D Printing Models.

This study aims to develop three-dimensional printing models of the bony nasal cavity and paranasal sinuses of big and domestic cats using reconstructed computed tomographic images. This work included an exhaustive study of the osseous nasal anatomy of the domestic cat carried out through dissections, bone trepanations and sectional anatomy. With the use of OsiriX viewer, the DICOM images were postprocessed to obtaining maximum-intensity projection and volume-rendering reconstructions, which allowed for the visualization of the nasal cavity structures and the paranasal sinuses, providing an improvement in the future anatomical studies and diagnosis of pathologies. DICOM images were also processed with AMIRA software to obtain three-dimensional images using semiautomatic segmentation application. These images were then exported using 3D Slicer software for three-dimensional printing. Molds were printed with the Stratasys 3D printer. In human medicine, three-dimensional printing is already of great importance in the clinical field; however, it has not yet been implemented in veterinary medicine and is a technique that will, in the future, in addition to facilitating the anatomical study and diagnosis of diseases, allow for the development of implants that will improve the treatment of pathologies and the survival of big felids.