BACKGROUND: The aim of this report was to assess the usefulness
of bone scanning in the diagnosis and evaluation of the
skull base osteomyelitis.

MATERIAL AND METHODS: Bone scanning was performed in
three male patients with otogenic skull base osteomyelitis, aged
65&#8211;84 years utilizing Tc99m-MDP and dual-head gamma camera.

RESULTS: In one case, bone scanning played a crucial role in
establishing the diagnosis. In two cases, it provided confirmed
MRI results. CT scanning was negative in two cases.

CONCLUSIONS: Bone scans may give valuable information for
establishing the diagnosis and assessing the severity of this
disease, and add complementary physiological information to
radiological imaging

Kowalska, Bożena

Lass, Piotr

Stankiewicz, Czesław

Stodulski, Dominik

Teodorczyk, Jacek

English

Via Medica Journals

33Nuclear Medicine Review 2005 Vol. 8, No. 1, pp. 33–36Copyright © 2005 Via MedicaISSN 1506–9680www.nmr.viamedica.plShortcommuni-cationsThe usefulness of bone scanningfor the diagnosis and evaluationof otogenic skull base osteomyelitis.A description of three casesCorrespondence to: Jacek TeodorczykDepartment of Nuclear MedicineMedical Universityul. Dębinki 7, 80–211 Gdańsk, PolandTel/fax: (+ 48 58) 349 22 04e-mail: teodorczyk@wp.plDominik Stodulski1, Jacek Teodorczyk2, Bożena Kowalska1,Czesław Stankiewicz1, Piotr Lass21Department of Otorhinolaryngology, Medical University, Gdańsk, Poland2Department of Nuclear Medicine, Medical University, Gdańsk, Poland[Received 16 II 2005; Accepted 28 IV 2005]AbstractBACKGROUND: The aim of this report was to assess the use-fulness of bone scanning in the diagnosis and evaluation of theskull base osteomyelitis.MATERIAL AND METHODS: Bone scanning was performed inthree male patients with otogenic skull base osteomyelitis, aged65–84 years utilizing Tc99m-MDP and dual-head gamma camera.RESULTS: In one case, bone scanning played a crucial role inestablishing the diagnosis. In two cases, it provided confirmedMRI results. CT scanning was negative in two cases.CONCLUSIONS: Bone scans may give valuable information forestablishing the diagnosis and assessing the severity of thisdisease, and add complementary physiological information toradiological imaging.Key words: bone scan, skull base osteomyelitis,malignant external otitisIntroductionSkull base osteomyelitis is a rare, but severe disease which isusually a complication of ear and paranasal sinus infections [1–4].Generally, it involves immuno-compromised individuals, the ma-jor subpopulation of patients are elder diabetics with long-lastingand poorly controlled disease. It was also noted in other immuno-deficiency conditions (AIDS, neoplasms), but cases with no clearimmunodeficiency were also described. Otogenic skull base os-teomyelitis (OSBO) usually follows malignant (necrotizing) exter-nal otitis, but it can also follow middle ear/mastoid infections. Inthe clinical course of malignant external otitis, the three followingstages may be distinguished: I — the process limited to soft ti-ssues; II — limited osteomyelitis; III — extensive osteomyelitis.Although Pseudomonas aeruginosa is responsible for most of thecases of OSBO, other pathogens have occasionally been isolat-ed such as Staphylococcus aureus, Proteus mirabilis and Aspergil-lus species. Progressing skull base osteomyelitis may lead toneurological complications e.g. cranial nerve palsy, venous sinusesand internal jugular vein thrombosis. It may be a life-threateningcondition, that may be difficult to diagnose and treat [1–4].Therapy of skull base osteomyelitis is complex and long-las-ting. It involves antibiotic treatment, hyperbaric oxygen therapy[2], improvement of underlying immune deficiency (e.g. diabetesmellitus regulation) and surgery. For confirmation of the diseaseand the start of intensive therapy typical findings of physical exa-minations, bacterial culture, pathological and laboratory testingare important, as well as diagnostic imaging of bone involvement.Material and methodsOur series comprised three male patients, aged 65–84 years,hospitalised with intense ear and head pain and neurological dys-function. Detailed data are given below.Bone scanning was performed using a dual-head gammacamera Multispect-2 (Siemens, Erlangen, Germany) 3–4 hours34Nuclear Medicine Review 2005, Vol. 8, No. 1www.nmr.viamedica.plShortcommuni-cationspost i.v. injection of 740 MBq of 99m-Tc-MDP (OBRI-Polatom,Otwock, Poland) using a low energy general purpose collimator.The data were collected into a 128 × 128 matrix for anterior, pos-terior and both lateral projections. Raw data were processedusing a Siemens ICON computer system.ResultsCase 1Patient PJ, male, aged 84, was admitted to the hospital withintense left-sided ear and head pain, progressive left hypoacusis,impaired function of ipsilateral mimic muscles, swallowing anddysartric speech. Complaints appeared a month before admi-ssion and increased gradually. Three months prior to admission,the patient was operated due to contralateral exacerbation ofchronic otitis media with conservative right ear surgery, duringwhich, sigmoid sinus delamination and mastoid region abscessdrainage were performed. Comorbid conditions included recentlydiagnosed diabetes mellitus type II, coronary artery disease, hy-pertension and ulcerative gastroduodenal disease. Physical exa-mination revealed signs of left-sided VII, IX, X, XI, XII cranial nervedysfunction. Audiogram showed right ear deafness and left earhypoacusis. Bacterial culture test from left ear tube revealedPseudomonas aeruginosa and Staphylococcus aureus species.A CT exam of the right ear showed the state after subtotalright mastoid process resection with preserved mastoid cells andtympanic cavity filled; in the left ear patent external acoustic me-atus, filled tympanic cavity and partially mastoid cells; bilaterallyacoustic chain bones and semicircular ducts symmetric, internalacoustic meatus symmetric, not dilated.Scintigraphy (Figure 1) revealed significantly increased up-take of radiotracer in the right temporal bone (predominantly inexternal acoustic meatus region) spreading towards and slightlycrossing the median plane of the body confirming skull base os-teomyelitis in the presence of uncertain CT scanning result.Four week antibiotic therapy  with ceftazidime and an applica-tion of hyperbaric oxygen expositions were performed giving clin-ical remission supported by triple negative culture test. Cranialnerve functions were not restored.Case 2Patient WL, male, aged 74 years, was admitted to the hospitalwith strong right ear and head pain, purulent ear exudate, pro-gressive hypoacusis, impairment of ipsilateral mimic muscles andswallowing functions. Complaints started five months before ad-mission and gradually increased. Four months ago, the patienthad right ear surgery — resection of polyps and squamae of cho-lesteatoma. Three months prior to admission, granulation the fromright external acoustic meatus was removed. Concomitant dis-eases were diabetes mellitus type II, coronary artery disease andhypertension. Physical examination revealed dysfunction of right-sided VII, IX–XII cranial nerves and left-sided pyramidal signs.Audiogram evidenced severe ipsilateral hypoacusis of mixed type.Bacterial culture test from the tube of the right ear revealedPseudomonas aeruginosa.Computed tomography and MRI visualized an extensive infil-tration of skull base bones and regional soft tissues, including thefollowing right-sided bone structures: portion of clivus and greaterwing of sphenoid bone, partially the pyramid of the temporal bone,inferior part of mastoid process, alveolar process of maxilla andanterior arch of atlas and subtemporal and pterygopalatal fossa.Scintigraphy (Figure 2) revealed significantly increased up-take of radiotracer in the right temporal bone spreading towardsmedian plane of the body. Radiotracer uptake was additionallyintensively increased in the paramedial region suggesting involve-ment of other skull base bones on the right.Six week antibiotic therapy with ceftazidime and ciprofloxacinand a course of hyperbaric oxygen therapy were performed withclinical remission supported by triple negative culture test. Cranialnerve functions were not restored.Figure 1. The result of bone scanning of Case 1.Ant LPost R35www.nmr.viamedica.plDominik Stodulski et al., Bone scanning in the diagnosis and evaluation of OSBOShortcommuni-cationsCase 3Patient BJ, male, aged 65 years, was admitted to the hospi-tal with intense left-sided head pain, vertigo, nausea, balancedisturbances impaired function of ipsilateral facial muscles andswallowing. These complaints appeared three weeks before ad-mission. For the three years prior to admission, the patient suf-fered from ipsilateral hypoacusis and temporal, intermittent pu-rulent ear exudates were observed. Two months before admi-ssion, the patient was hospitalized two times in another ENT de-partment, where chronic otitis media was diagnosed and i.v.antibacterial therapy was applied. Concomitantly, diabetes me-llitus type 2 and hypertension were additionally noted. Physicalexamination revealed peripheral dysfunction of VII, IX–XII ipsila-teral cranial nerves. Audiogram evidenced left-sided conductivehypoacusis. Bacterial culture test was repeated three times andwas negative.Computed tomography exam showed no osteolysis. MRI examrevealed extensive skull base infiltration expanding to contralateral side.Scintigraphy showed involvement of left temporal bone reach-ing the median plane of the body with predominance in the para-medial region (Figure 3). Scintigraphy confirmed extensive skullbase osteomyelitis.A bactericidal therapy with ceftazidime and ciprofloxacin aug-mented by hyperbaric oxygen was applied with no clinical improve-Figure 2. The result of bone scanning of Case 2.Ant PostR LAnt LR RFigure 3. The result of bone scanning of Case 3.36Nuclear Medicine Review 2005, Vol. 8, No. 1www.nmr.viamedica.plShortcommuni-cationsment. A second MRI exam revealed a progression of disease.Bacterial culture tests were repeated, finding Aspergillus fumiga-tus. Finally, an otogenic invasive fungal infection with extensiveskull base osteomyelitis was diagnosed. Antifungal therapy withi.v. amphotericin B and oral itraconazole was introduced, but grad-ual worsening of clinical condition occurred and the patient died53 days post admission to the hospital.DiscussionThe origin of pathological chain leading to skull base osteo-myelitis might be very innocent. For instance, scaring the skin ofthe external ear canal with cotton swab or traumatic injury of ex-ternal ear soft tissues can result in regional infection and inflam-mation (benign external otitis), in immunodeficient individuals, tend-ing to spread to adjacent bone.Long-lasting chronic otitis media is more likely to invade bonein immunocompromised patients. It may happen in an occult wayduring one of the exacerbations. The time of soft tissue progre-ssion into osteomyelitic disease may be unremarkable.A crucial factor for the success of therapy of several skull baseosteomyelitis variants is early diagnosis, which is difficult to achievewithout confirmation by imaging modalities. Commonly occurringsevere benign external otitis can mimic malignant external otitisand undermining diagnosis of the latter as a result [2]. Exacerba-tion of chronic otitis media and bone invasion may be overlookedamong patients with long-lasting complaints. The necessity forearly diagnosis (especially in immunocompromised individuals),risk of  diagnostic pitfalls and limitations of radiographic methodsin detecting early osteomyelitic changes open a diagnostic fieldfor bone scans.Bone scintigraphy reveals areas of  increased osteoblasticactivity, which may be developed by osteomyelitic, neoplastic andpost-traumatic processes, and must therefore be interpreted ina clinical context. Bone scintigraphy has a high diagnostic value, asit allows the detection of ostemyelitic changes before bone de-mineralization [5, 6]. The biggest disadvantage of bone scanningis the lack of specificity [7].Traditionally used conventional X-ray tomograms usually failto image the early stages of bone destruction where only a smallamount of demineralization has occurred.Computed tomography is a sensitive modality regarding de-tectable bone demineralization levels, but also may fail for smalldemineralisation [8]. CT findings are generally unhelpful for mo-nitoring response to treatment, because the CT scan may not evenbe abnormal initially or, if abnormal, may remain abnormal for aslongs as 2 years after treatment [8].Magnetic resonance imaging offers important, sensitive infor-mation about regional soft tissue involvement and neurologicalcomplications, Recognition of characteristic imaging findings suchas diffuse clival hypointensity on T1-weighted MR images due tobone marrow infiltration [9, 10] is crucial to making a timely diag-nosis, but is of limited value in direct diagnosis of early bony chang-es. Changes in bone scans tend to be present many years postosteomyelitis eradication, so the method is of limited value in state-ment of therapeutic success. In the final stages of therapy, 67Gascanning is useful, which has a significantly less pronounced ten-dency to persist positively after osteomyelitis eradication.Therefore, regarding coordinated diagnostic imaging, someauthors postulate that CT is best for differentiation between soft--tissue and bone infection, MR imaging is best for assessment ofthe calvaria and skull base and SPECT is best for assessment ofaltered bone and may be the best technique for follow-up [5].In our first case, bone scanning proved to be crucial in esta-blishing the diagnosis of early osteomyelitic changes in the pre-sence of unspecific CT exam results. In the two latter cases, itcorrelated with CT and MRI findings. Bone scans seem to be valu-able diagnostic tool, particularly important in immunodeficient in-dividuals cases where early diagnosis is crucial for therapeuticsuccess.References1. Chandler JR, Grobman L, Quencer R, Serafini A. Osteomyelitis of thebase of the skull. Laryngoscope 1986; 96 :245–251.2. Amorosa L, Modugno GC, Pirodda A. Malignant external otitis: re-view and personal experience. Acta Otolaryngol Suppl 1996; 521:3–16.3. Sreepada GS, Kwartler JA. Skull base osteomyelitis secondary to ma-lignant otitis externa. Curr Opin Otolaryngol Head Neck Surg 2003,11: 316–323.4. Grandis JR, Branstetter BF IV, Yu VL. The changing face of malignant(necrotising) external otitis: clinical, radiological, and anatomic corre-lations. Lancet Infect Dis 2004; 4: 34–39.5. Seabold JE, Simonson TM, Weber PC et al. Cranial osteomyelitis: di-agnosis and follow-up with In-111 white blood cell and Tc-99m met-hylene diphosphonate bone SPECT, CT, and MR imaging. Radiology1995; 196:779–788.6. Ohta H, Yonamine Y, Narabayashi I.What is the diagnosis? Malignantexternal otitis (MEO) (Pseudomonas osteomyelitis of the temporalbone). Ann Nucl Med 2003; 17: 698.7. Ceruse P, Mohammedi I, Muller P, Vautrin R, Truy E Diagnostic crite-ria for progressive necrotizing external otitis. Are scintigraphic find-ings reliable? Presse Med 1998; 27: 11–14.8. Rubin J, Curtin HD, Yu VL, Kamerer DB. Malignant external otitis: uti-lity of CT in diagnosis and follow-up. Radiology 1990; 174: 391–394.9. Kimura F, Kim KS, Friedman H et al. MR imaging of the normal andabnormal clivus. AJR Am J Roentgenol 1990; 155: 1285–1291.10. Erdman WA, Tamburro F, Jayson HT et al. Osteomyelitis: characteris-tics and pitfalls of diagnosis with MR imaging. Radiology 1991; 180:533–539.

The usefulness of bone scannning for the diagnosis and evaluation of otogenic skull base osteomyelitis. A description of three cases

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The usefulness of bone scannning for the diagnosis and evaluation of otogenic skull base osteomyelitis. A description of three cases

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