Is Computed Tomography an Adequate Imaging Modality for the Evaluation of Juvenile Ossifying Fibroma? A Comparison of 2 Imaging Modalities (Computed Tomography and Magnetic Resonance Imaging) Adepitan A. Owosho, BChD,* Marion A. Hughes, MD,y Joanne L. Prasad, DDS,z Anitha Potluri, DMD, MDsc,x Bernard J. Costello, MD, DMD,k and Barton F. Branstetter IV, MD{ Purpose:

Given the problems of overuse of medical technology and the current burden of health care cost in the United States, it is important to establish clear imaging guidelines to diagnose conditions such as juvenile ossifying fibroma (JOF). This study compared the efficacy of computed tomography (CT) and magnetic resonance imaging (MRI) in the evaluation of JOF and thus could aid establishing such guidelines.

Materials and Methods:

Radiologic criteria were established by 2 radiologists to compare the efficacy of CT and MRI in the evaluation of JOF. The following parameters were compared: presence of a welldefined corticated border, presence of a well-delineated internal calcified component, fluid-to-fluid levels, and anatomic extent of the lesion. Six patients diagnosed with JOF of the craniofacial bones from 2002 to 2013 had preoperative CT and MRI studies available for review.

Results:

After review of CT and MRI images, fluid-to-fluid levels and anatomic extent of the lesions were comparable on CT and MRI. However, the corticated borders and the internal calcified component were better defined on CT images, which also enabled for distinction between the 2 subtypes of JOF. No MRI characteristics were identified that allowed for this distinction.

Conclusion:

Based on these findings, CT is an adequate and preferable imaging modality in the evaluation of JOF. Ó 2015 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 73:1304-1313, 2015

{Professor of Radiology, Otolaryngology, and Biomedical

*Chief Resident, Department of Oral and Maxillofacial Pathology, University of Pittsburgh Medical Center, Pittsburgh, PA.

Informatics, Division of Neuroradiology, Department of Radiology,

yAssistant Professor, Division of Neuroradiology, Department of Radiology, University of Pittsburgh, Pittsburgh, PA.

University of Pittsburgh, Pittsburgh, PA. Address correspondence and reprint requests to Dr Potluri:

zAssistant Professor, Department of Diagnostic Sciences,

Department of Diagnostic Sciences, School of Dental Medicine,

School of Dental Medicine, University of Pittsburgh, Pittsburgh,

University of Pittsburgh, G119 Salk Hall, 3501 Terrace Street,

PA.

Pittsburgh, PA 15261; e-mail: [email protected]

xAssistant Professor, Department of Diagnostic Sciences, School of Dental Medicine, University of Pittsburgh, Pittsburgh, PA.

Received November 17 2014 Accepted January 17 2015

kProfessor of Craniofacial and Cleft Surgery, Department of Oral and Maxillofacial Surgery, School of Dental Medicine, University of Pittsburgh, Pittsburgh, PA.

Ó 2015 American Association of Oral and Maxillofacial Surgeons 0278-2391/15/00068-3 http://dx.doi.org/10.1016/j.joms.2015.01.013

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The term benign fibro-osseous lesion of the craniofacial bones encompasses a wide range of lesions sharing similar histopathologic features, but with distinctive imaging characteristics.1 These lesions include fibrous dysplasia, ossifying fibroma, osseous dysplasia (florid, periapical, and focal), and juvenile ossifying fibroma (JOF), a variant of ossifying fibroma that develops primarily within the craniofacial bones of young patients. Two distinct histopathologic subtypes of JOF have been described: psammomatous (JPOF) and trabecular (JTOF).2,3 Histopathologically, JPOF typically exhibits numerous spherical, psammoma-like, calcified bodies with concentric lamellae scattered within a fibrous stroma. In contrast, JTOF is characterized by bony trabeculae exhibiting varying degrees of mineralization that are surrounded by plump osteoblasts and set in a loose to densely collagenized fibrous tissue stroma. Poorly defined seams of immature osteoid arising from the

stroma also are typical of this variant.3 On occasion, multinucleated giant cells, mitotic figures, and aneurysmal bone cystlike changes are encountered and can be seen in either variant.4-7 Although the 2 subtypes have a predilection for the craniofacial bones, the favored site of occurrence of each subtype differs. JPOF commonly occurs within the paranasal sinuses but can develop in other sites, such as within the jaws or other craniofacial bones.2,4,8-10 These tumors are characterized by rapid growth with extension to the skull base and high recurrence potential.2,4,6 Comparatively, JTOF favors the jaw bones, with a predilection for the maxilla.2,5 JTOF also can exhibit rapid growth and expansion and can extend into adjacent structures, such as the paranasal sinuses and orbit. The role of imaging in distinguishing among the various benign fibro-osseous lesions of the jaws and craniofacial bones cannot be overemphasized.11

FIGURE 1. Case 1, psammomatous variant of juvenile ossifying fibroma. A, Axial computed tomographic view shows a ground-glass opaque mantle with central lucency, a well-delineated internal calcified component, and a well-defined cortical border. (Fig 1 continued on next page.) Owosho et al. Imaging of Juvenile Ossifying Fibroma. J Oral Maxillofac Surg 2015.

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FIGURE 1 (cont’d). B, Axial T1-weighted magnetic resonance image shows peripheral hypointense signals and central isointense signal. Owosho et al. Imaging of Juvenile Ossifying Fibroma. J Oral Maxillofac Surg 2015.

Accurate knowledge of the extent of the lesion and tumor borders is important to surgeons to determine the extent of the surgical resection. This is of particular importance given that recurrence might result from incomplete removal of the lesion. Computed tomography (CT) and magnetic resonance imaging (MRI) are the 2 main imaging modalities used in the evaluation of JOF and, to the authors’ knowledge, no study has adequately compared the efficacy of CT and MRI findings in the evaluation of this lesion. The authors recently described CT features of JPOF and JTOF in 12 patients, but the focus of that article was to compare the 2 variants of JOF to determine whether the 2 subtypes present with distinguishing radiologic features.1 The purpose of the present study was to compare the efficacy of CT and MRI in the evaluation of JOF, based on a specified set of parameters, to help establish guidelines that could prevent costly and unnecessary duplication of imaging studies.

Materials and Methods Fifteen patients were retrospectively identified with a histologically confirmed diagnosis of JOF at the authors’ institution from 2002 to 2013 (10 with JPOF and 5 with JTOF). Of these, 12 patients had imaging studies for review, and 6 of those patients (5 with JPOF and 1 with JTOF) had preoperative, concurrently obtained, CT and MRI studies available for review and comparison. Only cases with these 2 imaging modalities (CT and MRI) were included in the study. The typical skull base protocol for MRI included the following sequences: axial whole-brain T1-weighted spin-echo sequence, multiplanar T2-weighted fast spin echo sequences with or without fat saturation, and multiplanar T1-weighted spin-echo sequences with intravenous gadolinium enhancement. Studies captured by variable protocols were included if they had complete T1-weighted pre- and postcontrast and T2-weighted sequences (3 patients underwent MRI

OWOSHO ET AL

Table 1. SUMMARY OF CLINICAL, CT, AND MRI FEATURES

Parameters Reviewed Case

Gender

Age (yr)

Subtype

1

Corticated Border

Internal Calcified Component

Anatomic Extent

Fluid-To-Fluid Levels

F

15

JPOF

CT, well defined

CT, well delineated

CT and MRI correlate

not identified on CT or MRI

2

F

25

JPOF

MRI, poorly defined CT, well defined

MRI, poorly delineated CT, well delineated

CT and MRI correlate

identified on CT and MRI

3

M

13

JPOF

MRI, poorly defined CT, well defined

MRI, poorly delineated CT, well delineated

CT and MRI correlate

identified on CT and MRI

4

M

10

JPOF

MRI, poorly defined CT, well defined

MRI, poorly delineated CT, well delineated

CT and MRI correlate

identified on CT and MRI

5

M

2

JPOF

MRI, poorly defined CT, well defined

MRI, poorly delineated CT, well delineated

CT and MRI correlate

identified on CT and MRI

6

M

14

JTOF

MRI, poorly defined CT, well defined

MRI, poorly delineated CT, well delineated

CT and MRI correlate

not identified on CT or MRI

MRI, poorly defined

MRI, poorly delineated

Abbreviations: CT, computed tomography; F, female; JPOF, psammomatous variant of juvenile ossifying fibroma; JTOF, trabecular variant of juvenile ossifying fibroma; M, male; MRI, magnetic resonance imaging. Owosho et al. Imaging of Juvenile Ossifying Fibroma. J Oral Maxillofac Surg 2015.

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FIGURE 2. Case 2, psammomatous variant of juvenile ossifying fibroma. A, Axial computed tomographic view shows a ground-glass opaque mantle with central lucency, a well-delineated internal calcified component, and a well-defined cortical border. (Fig 2 continued on next page.) Owosho et al. Imaging of Juvenile Ossifying Fibroma. J Oral Maxillofac Surg 2015.

at outside institutions). T1 and T2 signal characteristics were categorized as hyperintense, isointense, or hypointense relative to gray matter. Maxillofacial CT (Lightspeed VCT and Optima CT660; GE Healthcare, Buckinghamshire, UK) with intravenous contrast was performed at 120 kVp, 240 mA, 1.25-mm collimation, 15- to 23-cm field of view, and a 0.53 pitch factor using associated reconstruction kernels. To compare the efficacy of the 2 imaging modalities, interobserver calibration was performed before reviewing the cases by setting specific parameters. The following parameters for each case were established, analyzed, and compared: 1) presence of a well-defined corticated border, 2) presence of a welldelineated internal calcified component, 3) presence of fluid-to-fluid levels, 4) and anatomic extent of the lesion on CT and MRI. Other variables, such as T1

and T2 signal characteristics and presence of enhancement on MRI, also were reviewed. The imaging studies were reviewed independently by 2 board-certified radiologists with extensive experience in head and neck imaging (M.A.H.) and oral and maxillofacial radiology (A.P.). After independent review, findings were compared and found to be in consensus. The study was approved by the institutional review board of the University of Pittsburgh (Pittsburgh, PA; number PRO14030104).

Results CLINICAL FEATURES

Of the 6 patients identified for this study, 4 were male and 2 were female. Ages ranged from 2 to

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FIGURE 2 (cont’d). B, Axial T1-weighted magnetic resonance image shows peripheral hypointense signals and central isointense signal. Owosho et al. Imaging of Juvenile Ossifying Fibroma. J Oral Maxillofac Surg 2015.

25 years. Five patients were diagnosed with JPOF and 1 patient was diagnosed with JTOF (Table 1). COMPUTED TOMOGRAPHY

CT scans were analyzed as previously described.1 All cases showed well-defined corticated borders and a clear bony encasement regardless of subtype. In addition, the internal calcified components of all cases were well delineated. The JPOF cases showed variation in the ground-glass pattern (Figs 1A, 2A, 3A), whereas the single JTOF case showed irregular, scattered, internal calcifications (Fig 4A). Fluid-to-fluid levels were observed in 4 cases (cases 2 to 5). Anatomic extent of the lesions was well defined in all 6 cases (Table 1). MAGNETIC RESONANCE IMAGING

In all cases, the cortical borders of the lesions were not well defined. In addition, the internal calcified

components of the lesions were poorly defined (Figs 1B, 2B, 3B, 4B). Fluid-to-fluid levels were observed on T2-weighted images in 4 cases (cases 2 to 5). However, no secondary aneurysmal bone cystlike changes were identified histopathologically. Anatomic extent of the lesions on MRI was well defined (Table 1). Other signal variables were reviewed, such as signal intensity of T1-weighted images with and without contrast and T2-weighted images. On T1-weighted images, the signal intensity of the ground-glass component of the JPOF cases observed on CT (cases 1 to 5) was nonspecific and varied from isointense to hypointense (Figs 1B, 2B, 3B), whereas the JTOF case (case 6) showed an isointense signal (Fig 4B). On T2-weighted images, the ground-glass component of the 5 JPOF cases (cases 1 to 5) displayed a hypointense signal and the JTOF case (case 6) also showed a hypointense signal. Presence of enhancement also was evaluated. The ground-glass component was enhanced on the

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FIGURE 3. Case 5, psammomatous variant of juvenile ossifying fibroma. A, Axial computed tomographic view shows a solid ground-glass opacity and a well-defined cortical border. (Fig 3 continued on next page.) Owosho et al. Imaging of Juvenile Ossifying Fibroma. J Oral Maxillofac Surg 2015.

T1-weighted postcontrast sequence in all JPOF cases. The JTOF case also was enhanced. The ground-glass component of the lesions (cases 1 to 4) showed a lower intensity compared with the central portion of those lesions on T1 and T2 sequences. When comparing the imaging findings noted on CT versus MRI, fluid-to-fluid levels and anatomic extent of the lesions were parameters that were comparable on CT and MRI. However, cortication of the tumor borders and the characteristics of the internal calcified component were better highlighted on CT images and enabled for distinction between the 2 subtypes of JOF. No MRI characteristics were identified that allowed for this distinction.

Discussion This study compared CT with MRI in the evaluation of JOF. The results showed some differences in the

information that could be obtained by CT and MRI. In particular, the corticated tumor borders and the characteristics of the internal calcified component were better defined on CT, although no observable differences between the 2 imaging modalities were noted with regard to the anatomic extent of the lesion and fluid-to-fluid levels. JOF commonly occurs in children, as seen in the present cases, with an older mean age in the JPOF versus JTOF subtype.12 Most cases of JPOF that present in adulthood actually might have started at a younger age as asymptomatic lesions of the paranasal region. Occult tumors are plausible given the location. Such lesions presumably would grow and much later present with swelling or other associated regional symptoms. Few reports have described MRI findings of JOF13-18 similar to the present findings. Han et al,17 in their report of 3 cases of JPOF, also noted that the ground-glass components of JPOF noted on

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FIGURE 3 (cont’d). B, Axial T1-weighted magnetic resonance image shows isointense signal. Owosho et al. Imaging of Juvenile Ossifying Fibroma. J Oral Maxillofac Surg 2015.

CT had a lower intensity compared with the central portion of the lesion on MRI T1-and T2weighted sequences. Management of either subtype of JOF is essentially the same and consists of complete surgical resection.15,19,20 However, proper identification of tumor borders is of great importance to the surgeon and will aid in determining the extent of the resection. Although benign, JOF can exhibit aggressive behavior consisting of rapid growth and recurrence of the lesion.2,4,6 Many recurrent cases are likely due to an incomplete resection of the tumor. In essence, it is important for the surgeon to be able to accurately identify the borders of this lesion to minimize the risk of recurrence, and the authors argue that CT provides sufficient resolution and highlights the corticated borders of this tumor. Also, the internal calcified component of the lesions was best delineated by CT, which enabled the differentiation of the 2 subtypes of JOF. In the

authors’ previous work,1 JPOF and JTOF could be distinguished by CT. No MRI characteristics were identified that allowed for this distinction. As seen in the present study, case 5 (JPOF) showed a homogeneous ground-glass opacity on CT (Fig 3A) that could easily be distinguished from JTOF (case 6), which showed a radiolucent lesion with irregular scattered calcifications (Fig 4A). However, on MRI the 2 tumors presented with no distinguishable features (Figs 3B, 4B). Based on this, a definitive radiologic diagnosis of JPOF or JTOF could not be rendered by MRI. It is well known that fine bone details and focal calcifications can be difficult to visualize on MRI.21 These advantages of CT over MRI in evaluating JOF were noted in a case report by Fakadej and Boynton18 who stated that MRI was not as helpful in making a diagnosis, whereas CT visualized the bony encasement of the tumor and best defined the borders. Although CT does allow for enhanced visualization of the corticated borders and of the internal calcified

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FIGURE 4. Case 6, trabecular variant of juvenile ossifying fibroma. A, Axial computed tomographic view shows an expansile, radiolucent mass with irregular scattered calcifications, a well-delineated internal calcified component, and a well-defined cortical border. (Fig 4 continued on next page.) Owosho et al. Imaging of Juvenile Ossifying Fibroma. J Oral Maxillofac Surg 2015.

portion of the tumor, cystic or secondary aneurysmal bone cystlike changes in JOF are not uncommon, and MRI will better demonstrate the fluid-to-fluid levels in such lesions. That said, CT with contrast also can visualize this finding. MRI is very useful in characterizing the soft tissue or intracranial extent of many skull base tumors, such as rhabdomyosarcoma, Ewing sarcoma or primitive neuroectodermal tumor, lymphoma, and esthesioneuroblastoma.21 However, this is not the case for JOF. There are limitations to this study. This is a singlecenter study of only 6 cases of JOF, including a single case of JTOF. As such, it does not lend itself to statistical analysis. It is unlikely that the imaging protocol had any role to play in skewing the findings of this study, because skull base protocols were used in MRI for 3 cases in the authors’ institution and showed similar results with the other 3 cases performed at outside institutions. Given the problems of overuse of medical technology and the current burden of health care cost in the

United States,22,23 it might be prudent to order CT with contrast as the primary investigative imaging study to evaluate a JOF or a suspected case of benign fibro-osseous lesion involving the craniofacial bones. It would likely be beneficial to see results of similar studies involving more cases to establish more concrete imaging guidelines for pathologic entities such as JOF. To avoid bias, interobserver calibration was performed by establishing image analyzing parameters. A formal cost analysis was not performed. However, preventing duplication of imaging studies in the evaluation of JOF is cost effective and cost saving. In the present study, CT and MRI were useful in determining the extent of the tumor. However, MRI was of little added diagnostic value. In addition, CT allowed for clear identification of the outer cortical border and the internal calcified component of the lesions. Therefore, CT without MRI is an adequate diagnostic tool for the evaluation of JOF.

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FIGURE 4 (cont’d). B, Axial T1-weighted magnetic resonance image shows uniform isointense signal. Owosho et al. Imaging of Juvenile Ossifying Fibroma. J Oral Maxillofac Surg 2015.

References 1. Owosho AA, Hughes MA, Prasad JL, et al: Psammomatoid and trabecular juvenile ossifying fibroma: Two distinct radiologic entities. Oral Surg Oral Med Oral Pathol Oral Radiol 118: 732, 2014 2. Makek M: Clinical Pathology of Fibro-Osteo-Cemental Lesions of the Cranio-Facial Skeleton and Jaw Bones. Basel, Switzerland, Karger, 1983, pp 128–227 3. Barnes L, Eveson J, Reichart P, Sidransky D: World Health Organization of Tumours. Pathology and Genetics of Head and Neck Tumours. Lyon, France, IARC Press, 2005 4. Johnson LC, Yousefi M, Vinh TN, et al: Juvenile active ossifying fibroma. Its nature, dynamics and origin. Acta Otolaryngol Suppl 488:1, 1991 5. Slootweg PJ, Panders AK, Koopmans R, Nikkels PG: Juvenile ossifying fibroma. An analysis of 33 cases with emphasis on histopathological aspects. J Oral Pathol Med 23:385, 1994 6. Margo CE, Ragsdale BD, Perman KI, et al: Psammomatoid (juvenile) ossifying fibroma of the orbit. Ophthalmology 92:150, 1985 7. Nasser MJ: Psammomatoid ossifying fibroma with secondary aneurysmal bone cyst of frontal sinus. Childs Nerv Syst 25: 1513, 2009 8. Yang HY, Zheng LW, Luo J, et al: Psammomatoid juvenile cemento-ossifying fibroma of the maxilla. J Craniofac Surg 20: 1190, 2009 9. Foss RD, Fielding CG: Juvenile psammomatoid ossifying fibroma. Head Neck Pathol 1:33, 2007 10. Marvel JB, Marsh MA, Catlin FI: Ossifying fibroma of the mid-face and paranasal sinuses: Diagnostic and therapeutic considerations. Otolaryngol Head Neck Surg 104:803, 1991 11. Waldron CA: Fibro-osseous lesions of the jaws. J Oral Maxillofac Surg 51:828, 1993

12. El-Mofty S: Psammomatoid and trabecular juvenile ossifying fibroma of the craniofacial skeleton: Two distinct clinicopathologic entities. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 93:296, 2002 13. Khoury NJ, Naffaa LN, Shabb NS, Haddad MC: Juvenile ossifying fibroma: CT and MR findings. Eur Radiol 12:S109, 2002 14. Nakajima R, Saito N, Uchino A, et al: Juvenile psammomatoid ossifying fibroma with visual disturbance: A case report with imaging features. J Neuroimaging 23:137, 2013 15. Breheret R, Jeufroy C, Cassagnau E, Malard O: Juvenile ossifying fibroma of the maxilla. Eur Ann Otorhinolaryngol Head Neck Dis 128:317, 2011 16. Rowland NC, Jermakowicz WJ, Tihan T, et al: Subacute cystic expansion of intracranial juvenile psammomatoid ossifying fibroma. J Neurosurg Pediatr 11:687, 2013 17. Han MH, Chang KH, Lee CH, et al: Sinonasal psammomatoid ossifying fibromas: CT and MR manifestations. AJNR Am J Neuroradiol 12:25, 1991 18. Fakadej A, Boynton JR: Juvenile ossifying fibroma of the orbit. Ophthal Plast Reconstr Surg 12:174, 1996 19. Bhat KV, Naseeruddin K: Sublabial approach to sinonasal juvenile ossifying fibroma. Int J Pediatr Otorhinolaryngol 64:239, 2002 20. Lund VJ, Howard DJ, Wei WI, Cheesman AD: Craniofacial resection for tumors of the nasal cavity and paranasal sinuses—A 17-year experience. Head Neck 20:97, 1998 21. Som PM, Curtin HD: Head and Neck Imaging (ed 4). St Louis, MO, Mosby, 2003 22. Kendall D, Quil B: Reduce Unnecessary Radiological Exams. Report on Economy, Health Care. Washington, DC, Third Way, 2014 23. Delaune J, Everett W: Waste and Inefficiency in the U.S. Health Care System. Cambridge, MA, New England Healthcare Institute, 2008

Is Computed Tomography an Adequate Imaging Modality for the Evaluation of Juvenile Ossifying Fibroma? A Comparison of 2 Imaging Modalities (Computed Tomography and Magnetic Resonance Imaging).

Given the problems of overuse of medical technology and the current burden of health care cost in the United States, it is important to establish clea...
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