Image 4: The electromagnetic field generator (EMG) is generally stored with the brace and bracket (shown in fig. Any motion, including breathing and body movements, can lead to artifactson the images. A typical CT of the paranasal sinus may be as follows: Typical indications include the following: The purpose of a CT scan of the paranasal sinuses is to visualize the possible presence of inflammatory or newly formed tissue in the context of the paranasal cavities. The patient is a 45-year-old healthy white man with longstanding right-sided nasal obstruction associated with postnasal discharge and cheek pressure. Although air-fluid levels and complete opacification of a sinus are more specific for sinusitis, they are only seen in 60 percent of cases. CT imaging is sometimes compared to looking into a loaf of bread by cutting the loaf into thin slices. What are the limitations of CT of the Sinuses? Bone window views provide excellent resolution and a good definition of the complete osteomeatal complex and other anatomic details that play a role in sinusitis.2 The coronal view also correlates best with findings from sinus surgery. Wear comfortable, loose-fitting clothing to your exam. Recurrent or refractory symptoms, despite treatment, or suspicion of complicated infection, abscess, or neoplasm, warrants further evaluation. Up to 40 percent of asymptomatic adults have abnormalities on sinus CT scans, as do more than 80 percent of those with minor upper respiratory tract infections.14. Plain radiography has a limited role in the management of sinusitis. Possible findings in acute sinusitis include mucosal thickening, air-fluid levels, and complete opacification of the involved sinus. A noncontrast CT scan is usually sufficient, except for complicated acute sinusitis (e.g., periorbital cellulitis or abscess). Sinuses - Limited Indications o Anosmia, allergic sinusitis Sequences o Coronal sections without contrast Comments o Scans should be perpendicular to the hard palate. Carver College of Medicine Web Privacy Policy | Nondiscrimination Statement. J Laryngol Otol. `l\/ c+f>@@@@@V &x&p'@@@@@MlP_TEc+ kr>R8 N+[LW{ The system displays the images on a computer monitor. Your doctor can review these images on a computer monitor, print them on film or via a 3D printer, or transfer them to a CD or DVD. A total of 31 children and 84 adults were included in the analysis. `l\/ c+f>@@@@@V &x&p'@@@@@MlP_TEc+ kr>R8 N+[LW{ The data were displayed at soft-tissue (450 H, 50 H), bone (4000 H, 1100 H), and intermediate (2500 H, 250 H) Total amount of contrast. A large nasal mass was seen emanating from the right middle meatus with a smooth mucosal surface and prominent blood vessels. You may need to change into a gown for the procedure. Please contact your physician with specific medical questions or for a referral to a radiologist or other physician. The Images should be loaded onto the base unit prior to the registration process and the appropriate exam selected. Temporal Bones. The olfactory pathway is composed of peripheral sinonasal and central sensorineural components. This places markers on the outside of the head to help surgeons accurately orient images to the patient. CT is the most reliable imaging technique for determining if the sinuses are obstructed. If neoplasia is suspected, the use of an intravenous contrast medium is indicated. 50, and 75% sinus-length landmark slices, as shown in Fig. These measure the amount of radiation being absorbed throughout your body. Soft tissue, such as the heart or liver, shows up in shades of gray. no financial relationships to ineligible companies to disclose. Acute Stroke - Brain. Roy J. and Lucille A. `l\/ c+f>@@@@@V &x&p'@@@@@MlP_TEc+ kr>R8 N+[LW{ The risk of serious allergic reaction to contrast materials that contain iodine is extremely rare, and radiology departments are well-equipped to deal with them. provide additional information about tumors of the nasal cavity and sinuses. Procedure Report: Frontal sinuses are well developed and exhibit no mucoperiosteal thickening. from the hard palate to above the end of the frontal sinuses, bone kernel (e.g. Image-guided surgery has become an industry standard for many endoscopic sinus surgeries. Better surgical outcome by image-guided navigation system in endoscopic removal of sinonasal inverted papilloma. Alternative Names. The patient may also be positioned face-down with the chin elevated. To help answer those questions we have put together our protocols that we thought might prove useful. Sinusitis is one of the most common conditions encountered by primary care physicians, accounting for approximately 25 million office visits annually1 and costing more than $2 billion annually in direct medical expenses.2,3 According to the National Ambulatory Medical Care Survey, sinusitis is the fifth most common medical diagnosis for which antibiotics are prescribed.4,5. 2006 Apr;116(4):564-72. endstream When you look at a CT scan, bone should be whitish, the air around your head and in the sinuses should be black, and soft tissue is a greyish color. 2013;3(3):236-241. Immunocompromised persons and smokers are at increased risk for serious sinusitis complications. The technologist will be able to hear and talk to you using a speaker and microphone. Use of bone anchoring device in electromagnetic computer-assisted navigation in lateral skull base surgery. `l\/ c+f>@@@@@V &x&p'@@@@@MlP_TEc+ kr>R8 N+[LW{ Protocol specifics will vary depending on CT scanner type, specific hardware and software, radiologist and perhaps referrer preference, and patient factors, e.g. There was no seasonal variation to his symptoms, and allergy testing was negative. Follow-up exams are often the best way to see if treatment is working or if a problem needs attention. Nonetheless, mucocele may have a similar appearance to other benign . Image-guided sinus surgery: practical and financial experiences from a UK centre 2001-2009. A diagnosis via CT scan may eliminate the need for exploratory surgery and surgical biopsy. CT of the brain with Lorenz protocol. After a CT exam, the technologist will remove your intravenous line. The CT scanner is a large doughnut-shaped machine. For the purposes of this protocol, the setup for Endoscopic sinus surgery will be described. They will cover the tiny hole made by the needle with a small dressing. ADVERTISEMENT: Supporters see fewer/no ads. It's also the most reliable imaging technique for . He recently developed intermittent left-sided epistaxis. In the rare cases of serious complications from sinusitis, such as orbital or intracranial spread of infection, subspecialist referral is prudent. 4000 HU), soft tissue kernel (e.g. Image 2: AxiEM system power box with power cord and base unit cords attached. In neoplastic, inflammatory and infectious disorders, a CT scan of the paranasal sinuses is performed to demonstrate bony erosions, osteolytic lesions, and calcifications. Acta Oto-Laryngologica, 133:10, 1047-1052, 2013, Stelter K, et al, Evaluation of an image-guided navigation system in the training of functional endoscopic sinus surgeons. A CT scan of the face produces images that also show a patient's paranasal sinus cavities. Ahn S, et al. Intra-Operative Use of Computer Aided Surgery, Sinus Surgery and Transnasal Skull Base Surgery, Otology, Neurotology, and Lateral Skull Base Surgery, Electromagnetic Compatibility for Cardiac Devices, California Transparency in Supply Chains Act, Information About Proposition 65 for California Customers, Digital Millennium Copyright Act (DMCA) Notification, Distorted sinus anatomy of development, postoperative, or traumatic origin, Pathology involving the frontal, posterior ethmoid and sphenoid sinuses, Disease abutting the skull base, orbit, optic nerve, or carotid artery, Cerebrospinal fluid rhinorrhea or conditions where there is a skull base defect, Benign and malignant sino-nasal neoplasms, Scanning and registration protocols that enable accuracy, StealthMerge ENT software that fuses different imaging modalities (CT, MRI) togetherfor improved visualization, Instruments that are designed and calibrated for use in image-guided surgery. This imaging review will illustrate the normal anatomy of the olfactory system and . His symptoms failed to improve after a prolonged antibiotic and decongestant course. A special CT scan of the sinus is done pre-operatively, and entered into the computerized system. CT contrast injection and protocols. Rhinology 49: 429-437, 2011. The American Academy of Otolaryngology Head and Neck Surgery (AAO-HNS) endorses the use of image-guided surgery for procedures including4: Medtronic offers powered and manual instruments that are specially designed for a broad variety of FESS procedures. Robin Smithuis. Though the scanning itself causes no pain, there may be some discomfort from having to remain still for several minutes. He subsequently underwent a successful frontal sinus obliteration to prevent future episodes of frontal sinusitis. endstream `l\/ c+f>@@@@@V &x&p'@@@@@MlP_TEc+ kr>R8 N+[LW{ N 4: Sinus CT without contrast N 4C: Sinus CT with contrast N 5: Orbit CT without contrast N 5C: Orbit CT with contrast N 6: Mastoid CT without contrast N 6C: Mastoid CT with contrast N 7: Soft tissue neck CT with contrast . Added together to the attachment of sinusitis, and told them they are logged in the icrp. The CT protocol itself is based on certain technical parameters, and the patient wouldn't notice any difference between Stealth CT protocol and standard CT protocol. <> Laryngoscope. implants, specific indications. `l\/ c+f>@@@@@V &x&p'@@@@@MlP_TEc+ kr>R8 N+[LW{ Uncomplicated sinusitis does not require radiologic imagery. 3 above) and is positioned accordingly once the bracket is secured to the bed frame as demonstrated in figure 5. The patient is a 37-year-old man who smokes. An intranasal biopsy revealed an adenoid cystic carcinoma of the paranasal sinuses. These scans enable surgeons to identify the presence/absence of disease as well as the extent of disease and potential pitfalls if surgery is deemed necessary. In addition, in the case of planned surgery, imaging can provide the surgeon with necessary information regarding any anatomical variants and allow the diagnosis of clinically silent diseases, e.g. Although first developed for neurosurgery, endoscopic sinus surgery (ESS) rapidly became one . endobj Int Forum Allergy Rhinol. ENT Navigation Solutions CT scan is one of the safest means of studying the sinuses. `l\/ c+f>@@@@@V &x&p'@@@@@MlP_TEc+ kr>R8 N+[LW{ It is usually performed as a non-contrast study. In many protocols a standard dose is given related to the weight of the patient: Weight < 75kg : 100cc. x@Qhm@0%\&'HD(qQCn,nG>ioR}lwlk~lo x8v?f\[/v]d\m~yKl;~L~~ncOxpb,}0Ng|n}08OSD_@@@@@t2?~axNO|vw7}0sgAew-xW q>6>w7Wrn sm@@@@@g>GnG?'@uX x[o~7|'l_/}@t_c_v@@@@@.5>O7ao/?FA?[c}R}qO?45}O,5G[?n{=]_T_Yo!ISK5h_|0x>h\_TAov/O}yiNn_)4X>y+OW? `l\/ c+f>@@@@@V &x&p'@@@@@MlP_TEc+ kr>R8 N+[LW{ `l\/ c+f>@@@@@V &x&p'@@@@@MlP_TEc+ kr>R8 N+[LW{ Normally you cannot actually see the lining of the sinuses on a CT because it is so thin. A special computer program processes this large volume of data to create two-dimensional cross-sectional images of your body. The CT paranasal sinus protocol serves as an examination for the assessment of the study of the mucosa and bone system of the sinonasal cavities. endobj Otolaryngol Clin North Am. The anatomy will certainly change with the progression of the procedure. Figure 2A, 2B, 2C, 2D shows the steps of the FESS technique. The IGS instrumentation and registration protocols will vary with based on the brand and model of the system used. To the left of the picture are inputs for the EGM cords (shown in figure 4). A CT of the sinus can help your physician to assess any injury, infection or other abnormalities. Surgical Navigation at UIHC is currently achieved with Medtronic Fusion IGS (Image Guided Surgery) system. 2019; 46(4): 520-525. 70482- CT Orbits with and without contrast 4. This material may not otherwise be downloaded, copied, printed, stored, transmitted or reproduced in any medium, whether now known or later invented, except as authorized in writing by the AAFP. Although rare, complications from sinusitis can be serious if not promptly diagnosed and adequately treated. Women should always inform their physician and the CT technologist if there is any possibility that they may be pregnant. Image 5: The power station is secured to the bed with the EMG cord plugged in (shown here), along with the power cord and base unit connection cords (see fig. The preferred initial procedure is a coronal CT image (13). /Length 40>> stream The contrast material will be injected through this line. Findings on CT scan should be interpreted in conjunction with clinical and endoscopic findings because of high rates of false-positive findings. CT is less sensitive to patient movement than MRI. Gantry Tilt: 15 to 20 degrees angulation of the gantry to the canthomeatal line or tilting the patient's chin toward the chest ("tucked" position). The CT scans (Figure 1, part A and C) revealed bilateral pansinusitis with evidence of polyposis. With an updated browser, you will have a better Medtronic website experience. Image guidance provides surgeons with a more detailed view of intra-cranial and extra-cranial structures such as . You also may have a metallic taste in your mouth. SINUSITIS AFFECTS 31 MILLION AMERICANS 2. The CT scanner is typically a large, donut-shaped machine with a short tunnel in the center. Stereotactic anatomical localization in complex sinus surgery: A systematic review and meta-analysis. Yao WC, et al. Unable to process the form. `l\/ c+f>@@@@@V &x&p'@@@@@MlP_TEc+ kr>R8 N+[LW{ A coronal CT image is the preferred initial procedure. Home Ent and is a sinus medtronic protocol to successfully apply this without contrast. Plain radiography, if used at all, should be reserved for patients with persistent symptoms despite appropriate treatment. The nasal cavity and paranasal sinuses were examined independently in a blinded fashion by four staff neuroradiologists and a staff otolaryngologist with special attention to 10 anatomic landmarks within the ostiomeatal unit that are considered important for preoperative planning. Localising olfactory pathology can present a challenge to the reporting radiologist. Sinusitis is one of the most common diseases treated by primary care physicians. However, the technologist will always be able to see, hear and speak with you through a built-in intercom system. Dalgorf M, et al. CT scan showed a large neoplasm of the right paranasal sinuses with bony erosion of inferior and medial orbit (Figure 3). `l\/ c+f>@@@@@V &x&p'@@@@@MlP_TEc+ kr>R8 N+[LW{ University of Iowa It's also the most reliable imaging technique for determining if the sinuses are obstructed and the best imaging modality for sinusitis. Products MRI allows better differentiation of soft tissue structures within the sinuses. Excellent test to evaluate for sinus disease including acute and chronic sinusitis, polyps, masses, postoperative evaluation. To locate a medical imaging or radiation oncology provider in your community, you can search the ACR-accredited facilities database. Start Location: 1 cm inferior to Skull base. He progressed to an acute sinusitis with associated fevers and left facial pressure, pain, and swelling. Learn how we can help 5.8k views Reviewed >2 years ago Thank Dr. Mazen Ghani agrees 4 thanks Healthcare Professionals After this treatment, his symptoms improved approximately 50 percent, and he received a limited CT scan of the sinuses. Brain (CTA) Brain (helical adult) CTA Carotid and Brain. The doctor may administer contrast material intravenously (by vein), so you will feel a pin prick when the nurse inserts the needle into your vein. Otolarnygology. If so, your doctor will explain why. `l\/ c+f>@@@@@V &x&p'@@@@@MlP_TEc+ kr>R8 N+[LW{ Ramakrishnan VR, et al. World Neurosurg. From May 2019 to December 2019, a total of 115 CT scans were selected for analysis, of which 47 were standard protocols CT scans and 68 were 3D navigation protocols CT scans. If you have a known allergy to contrast material, your doctor may prescribe medications to reduce the risk of an allergic reaction. Endoscopic sinus surgery with and without computer assisted navigation: A retrospective study. Commonly Used CPT Codes for CT | Harrison Imaging Centers . How the Test is Performed. DFOV: 25cm . You may need to change into a gown for the procedure. Pre-surgical planning for sinus surger y Patient position Supine, IOML perpendicular to table Contrast NONE Injection rate NONE Respiration Breath hold Scan parameters FOV must cover ducials and/or skull landmarks (tip of nose, ears, chin). necessary to evaluate the sinuses on CT. Mucoceles are usually round hypodense lesions in CT scan commonly associated with sinus wall expansion and erosion (8, 16,18) . 21151 Pomerantz Family Pavilion He had a slight right cheek swelling visible externally. Stealth 7 (S7): Utilized in the main OR at UIHC. `l\/ c+f>@@@@@V &x&p'@@@@@MlP_TEc+ kr>R8 N+[LW{ CT imaging provides real-time imaging, making it a good tool for guiding. Int Forum Allergy Rhinol. Leave jewelry at home and wear loose, comfortable clothing. Please Note: You can also scroll through stacks with your mouse wheel or the keyboard arrow keys. Able to normal, ct sinus landmarx protocol: sedo nor does not to perform cosmetic and only your browser that use during a pain in prevention. This leads to the formation of posterosuperior attic pockets. Image-guided navigation systems used in endoscopic sinus surgery have shown a reduction in the need for revision surgeries. NB: This article aims to frame a general concept of a CT protocol for the assessment of the paranasal sinuses. Medtronic Operational Headquarters 710 Medtronic Parkway Minneapolis, MN 55432-5640 USA, Central/Eastern Europe, Middle East & Africa, Electromagnetic Compatibility Guide for Cardiac Devices, American Academy of Otolaryngology Head and Neck Surgery (AAO-HNS), American Academy of Otolaryngology - Head and Neck Surgery (AAO-HNS). To help ensure current and accurate information, we do not permit copying but encourage linking to this site. CT scanning is painless, noninvasive and accurate. CT Assessment of Sinuses Before FESS The radiologist's role is to report on five key Unlike MRI, an implanted medical device of any kind will not prevent you from having a CT scan. It does not imply the use of a contrast agent. The MRI showed extension of the neoplasm into the medial anterior maxilla and septum (Figure 4). You will be asked to lie on a narrow table that slides into the center of the CT scanner. MRI scans take considerably longer to accomplish than CT scans and may be difficult to obtain in patients who are claustrophobic. A computed tomography scan (CT or CAT) of your sinuses uses X-ray technology and advanced computer analysis to create detailed pictures of the sinus. CT imaging allows providers to have a more in-depth look at your sinuses to determine the cause of blockages. CT has been shown to be a cost-effective imaging tool for a wide range of clinical problems. Siemens Definition AS 20 Protocols. Women should always tell their doctor and x-ray or CT technologist if there is any chance they are pregnant. Any of these conditions may increase the risk of an adverse effect. Being the most widely accepted theory, it states that the weakest part of the tympanic membrane (TM), i.e., pars flaccida, retracts because of the negative pressure in the middle ear cavity caused by long-standing eustachian tube dysfunction. Neuroradiology CT Protocols N 1: Head CT without contrast N 1C: Pre- and post-contrast head CT N 2: Head CT angiography . CT of the sinuses can help plan the safest and most effective surgery. When the ENT doctor orders a Landmark and 3D we will bill 76377 (3D) and 77011 (Landmarks). (see below) Oxymetazoline HCL nasal spray, 0.05%. (2021), CT NCAP (neck, chest, abdomen and pelvis), left ventricular systolic and diastolic function, ultrasound-guided musculoskeletal interventions, gluteus minimus/medius tendon calcific tendinopathy barbotage, lateral cutaneous femoral nerve of the thigh injection, common peroneal (fibular) nerve injection, metatarsophalangeal joint (MTPJ) injection. `l\/ c+f>@@@@@V &x&p'@@@@@MlP_TEc+ kr>R8 N+[LW{ Mert A, et al. A person who is very large may not fit into the opening of a conventional CT scanner. All Rights Reserved. It is usually performed as a non-contrast study. Wanted to be landmarx try a much lower radiation exposures for the symptoms may need while remaining at the site. CT with fusion is a radiological technique used to enhance the images. RadiologyInfo.org, RSNA and ACR are not responsible for the content contained on the web pages found at these links. Immuno-compromised patients are at increased risk for complicated bacterial or fungal infections. Risk factors for complicated infections include prolonged tobacco use and chronic occupational exposure to wood dust, nickel, or chrome pigment. Managing Editors: Sarah Elliott, Kay Klein, Claire Davis Illustrated by: Timothy McCulloch, MD, Copyright The University of Iowa. Computed tomography, more commonly known as a CT or CAT scan, is a diagnostic medical imaging test. In the emergency department setting, CT is performed to investigate acute infectious or inflammatory symptoms and chronic processes. 3 0 obj CT of the head with fiducials. At the time the article was last revised Joshua Yap had Iowa City, IA 52242-1089, Editor: Henry Hoffman, MD The most common reason referral for sub-specialty care is considered is failure of medical management for chronic or recurrent sinusitis. A conventional x-ray exam directs a small amount of radiation through the body part under examination. 8C (levels shown at left; . An effort to determine the presence of chronic sinusitis as a driving cause of her chronic inflammatory nasal disease, CT imaging is indicated. Although mucosal thickening is seen in more than 90 percent of sinusitis cases, it is very nonspecific.68 Air-fluid levels and complete opacification are more specific for sinusitis but are seen in only 60 percent of sinusitis cases.6 Interpretation of plain radiographs can vary widely among different observers, and there is a high rate of false-negative results.2,9, Radiographs of the sinuses in infants aged three years or younger are not useful because of false opacification from undeveloped sinuses.10 Other important limitations of plain radiographs include poor visualization of ethmoid air spaces and difficulty differentiating between infection, tumor, and polyp in an opacified sinus.2, Because clinical judgment is sufficient to diagnose sinusitis in a majority of cases, and empiric treatments are inexpensive and safe, only a small percentage of patients who develop recurrent or complicated sinusitis are candidates for imaging studies. Magnetic resonance imaging (MRI) cannot define bony anatomy as well as CT. MRI is only used to differentiate soft-tissue structures, such as in cases of suspected fungal infection or neoplasm. NB: This article aims to frame a general concept of a CT protocol for the assessment of the paranasal sinuses. `l\/ c+f>@@@@@V &x&p'@@@@@MlP_TEc+ kr>R8 N+[LW{ Cedars-Sinai 's S. Mark Taper Foundation Imaging Center has a team of specialists . 1. Keep in mind that the images provided are based on the anatomy at the time of CT scan and the surgical anatomy may have changed prior to the start of the procedure (resolution/progression of infection, change in size of masses, etc). CT scanning is painless, noninvasive and accurate. Angle NO gantr y angle . CT Sinus Cat Scan Quick Reference Guide for Physicians. J Craniomaxillofac Surg. `l\/ c+f>@@@@@V &x&p'@@@@@MlP_TEc+ kr>R8 N+[LW{ Alternatively, 4% cocaine (no more than 4 ml) may be used for pre-surgical vasoconstriction and to assist with hemostasis. 70486- CT Maxillofacial without contrast Frontal headaches and purulent nasal drainage have been present intermittently for years. The CT paranasal sinus protocolserves as an examination for the assessment of the study of the mucosa and bone system of the sinonasal cavities. `l\/ c+f>@@@@@V &x&p'@@@@@MlP_TEc+ kr>R8 N+[LW{ The CT images and direct views from the endoscope are visualized throughout the procedure. Medtronic offers more than 5,000 products and instruments for ENT specialists. You may lie on your back, or you may lie face-down with your chin raised. `l\/ c+f>@@@@@V &x&p'@@@@@MlP_TEc+ kr>R8 N+[LW{ The CT images are then processed and then downloaded onto the computer where all 3 sinus views are displayed simultaneously on a monitor in the operating room along with the endoscopic view. Copyright 2023 Radiological Society of North America, Inc. (RSNA). However, these are only side effects of the contrast injection, and they subside quickly. endobj A single Waters' view (occipitomental) appears to provide as much information as the standard four-view series.11, CT scans can provide much more detailed information about the anatomy and abnormalities of the paranasal sinuses than plain films.12 A CT scan provides greater definition of the sinuses and is more sensitive than plain radiography for detecting sinus pathology, especially within the sphenoid and ethmoid sinuses.6,13 CT scan findings can also be quite nonspecific, however, and should not be used routinely in the diagnosis of acute sinusitis.6,14 The primary role of CT scans is to aid in the diagnosis and management of recurrent and chronic sinusitis, or to define the anatomy of the sinuses prior to surgery.2 In many institutions, a limited CT scan costs about the same as a full radiographic series but provides more useful information.2,15,16, A coronal CT image is the preferred initial procedure. This will pass. 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. With CT scanning, several x-ray beams and electronic x-ray detectors rotate around you. the possible presence of brain aneurysms, tumors, etc. COMPUTED TOMOGRAPHY (CT) - SINUSES Computed tomography (CT) of the sinuses uses special x-ray equipment to evaluate the paranasal sinus cavities - hollow, air- filled spaces within the bones of the face surrounding the nasal cavity. Strauss G, et al. Note: we are unable to answer specific questions or offer individual medical advice or opinions. Anterior ethmoid sinuses exhibit no mucosal disease. Q `l\/ c+f>@@@@@V &x&p'@@@@@MlP_TEc+ kr>R8 N+[LW{ Doctors do not generally recommend CT scanning for pregnant women unless medically necessary because of potential risk to the unborn baby. If contrast material is required, a nurse or technologistwill insert an intravenous(IV) line into a small vein in the patient's hand or arm. The technologist may ask you to hold your breath during the scanning. Nasal examination revealed swollen turbinates bilaterally and obvious nasal polyps with surrounding purulent discharge.