• 沒有找到結果。

Twenty classic signs in oral and maxillofacial radiologyGalal Omami

N/A
N/A
Protected

Academic year: 2022

Share "Twenty classic signs in oral and maxillofacial radiologyGalal Omami"

Copied!
8
0
0

加載中.... (立即查看全文)

全文

(1)

Abstract

Teachers of radiology often employ the use of classic signs to help learners identify the typical appearance of various pathologies. This article is a compendium of simply-described classic signs in oral and maxillofacial radiology, including their use in differential diagnoses.

Keywords Classic signs · Education · Oral radiology · Diagnostic imaging

Introduction

Over the years, radiologists have established many meta- phorical imaging signs to attribute meaning to disease- or anatomy-specific imaging patterns encountered in the clini- cal setting. Oral and maxillofacial imaging is no exception.

As a specialty that deals with uncommon lesions and com- plex anatomy, both students and practicing dental clinicians may benefit from this simplistic, pattern-based approach.

This review describes a compendium of the classic signs in oral and maxillofacial radiology and discusses their use in differential diagnoses. Unless otherwise acknowledged, all images are courtesy of the author’s personal collection.

Classic imaging patterns

“Soap bubble and honeycomb” appearances

The internal structure of solid/multicystic ameloblastoma is typically mixed, with the presence of bony septa creating multiple internal compartments, or loculations. This pattern reflects the presence of cystic formations within the tumor.

These cystic regions remodel the trapped bone into curved shapes, providing a “soap bubble” pattern (large radiolucent compartments of variable size) or a “honeycomb” pattern (numerous small compartments) (Fig. 1). Generally, the compartments are large in the posterior mandible and small in the anterior mandible [1]. The soap bubble pattern may also be observed in odontogenic keratocysts and giant cell granulomas [2] (Fig. 2). Odontogenic myxomas, however, sometimes display a small number of straight, thin septa, resembling strings in a tennis racket.

“Sunray” appearance

Osteosarcoma is the second most common primary malig- nant bone tumor, with multiple myeloma the first [3].

Osteosarcomas can stimulate the formation of thin, straight spicules of bone, giving a “sunray” or “hair-on-end” appear- ance (Fig. 3). This formation occurs when the periosteum is displaced, partially destroyed, and/or disorganized [4].

Chondrosarcomas, fibrosarcomas, and metastatic breast and prostate tumors may also exhibit bone production with a

“sunray” appearance [5].

“Spiked root” appearance

Benign tumors tend to resorb adjacent root surfaces in a smooth fashion. When root resorption is associated with malignant disease; however, the resorption often occurs in smaller quantities, causing thinning of the root into a

“spiked” shape [6] (Fig. 4). In the absence of generalized periodontitis, widening of the periodontal ligament space that involves one or several adjacent teeth (characteristically

Galal Omami: Diplomate, American Board of Oral and Maxillofacial Radiology.

* Galal Omami Galal.Omami@uky.edu

1 Department of Oral Health Practice, Division of Oral Medicine, Diagnosis and Radiology, University of Kentucky College of Dentistry, 800 Rose Street, Room MN-320, Lexington, KY 40536-0297, USA

(2)

limited to one side of the root) could be an early sign of malignancy (Garrington’s sign) [7] (Fig. 4).

“Sharpened pencil” appearance

Approximately 50% of patients with rheumatoid disease have temporomandibular joint (TMJ) involvement [8].

Rheumatoid arthritis is characterized by synovial prolifera- tion (pannus) and secondary erosive changes in the bone.

Images of the TMJ often show progressive erosion at the attachment of the synovial lining of the anterior and poste- rior condylar surfaces, resulting in a small, pointed condyle in a large fossa (“sharpened pencil” appearance) (Fig. 5).

Eventually, the entire condyle may be destroyed, with only the neck remaining as the articulating surface.

“Tram‑track” appearance

Monckeberg’s medial vascular calcification (arterioscle- rosis) is characterized by degeneration and subsequent deposition of calcium in the medial coating of the artery.

These deposits, however, do not narrow the vessel lumen or interfere with blood flow [9]. This type of calcification is most frequently seen in patients with diabetes mellitus or chronic renal failure [10]. Radiographically, the calcified vessel appears as a parallel pair of thin, radiopaque lines that outline the affected vessel. It is described as having a “tram- track” or “pipe stem” appearance (Fig. 6).

“Sausage‑string” appearance

Sialodochitis is defined as inflammation of the ductal system of either the parotid or submandibular gland. It results in dilation of the involved duct secondary to distal

Fig. 1 Ameloblastoma of the left mandibular body. Panoramic view of the lesion shows numerous small compartments (“honeycomb”

pattern)

Fig. 2 Cherubism. Panoramic image shows bilateral, multilocular

“soap bubble” lesions and significant jaw expansion. The internal structure is indistinguishable from a central giant cell granuloma (Courtesy Dr. Behrang Moghaddamzade, Tehran, Iran)

Fig. 3 Osteosarcoma of the mandible. Cross-sectional cone-beam computed tomography (CBCT) image shows an exuberant periosteal reaction with a “sunburst” pattern (Courtesy 3 Dimension Imaging, Allahabad, India)

Fig. 4 Osteosarcoma of the mandible. Note the increased bone den- sity and irregular widening of the periodontal ligament spaces of the teeth of the left mandibular body (Garrington’s sign). Also, note the

“spiking” resorption of the mesial root of the first molar

(3)

obstruction. If interstitial fibrosis develops, however, it is seen on sialography as a “sausage-string” in the main and secondary ducts that is produced by intermittent strictures and dilations [11] (Fig. 7). More recently, these findings

on a coronal computed tomographic (CT) image, as is the

“trapdoor” appearance of the displaced orbital floor. These signs are accompanied by an air–fluid level in the subjacent maxillary sinus (Fig. 8).

“Punched‑out” appearance

A “punched-out” border is one that has a sharp boundary with no peripheral bone reaction. Its appearance is similar to that of a hole in a radiograph created with a paper punch.

The border of the resulting hole is well-defined, and the sur- rounding bone has a normal appearance up to the edge of the hole. “Punched-out” lesions are typically indicative of mul- tiple myeloma or Langerhans cell histiocytosis [14] (Fig. 9).

“Ground‑glass” appearance

The radiological features of fibrous dysplasia vary con- siderably depending on the maturity of the lesion [15].

In the early stage, fibrous dysplasia appears as a unilocu- lar or multilocular radiolucency with ill-defined or well- defined borders. In the middle stage, radiopaque tissue appears in the radiolucent structure. In the mature stage, the internal structure has a granular, radiopaque pattern

Fig. 5 Rheumatoid arthritis presented with temporomandibular joint (TMJ) pain and stiffness. Coronal CBCT image of the TMJ shows small remnants of the condylar heads after severe erosion, resulting in a “sharpened pencil” appearance of the condyle

Fig. 6 Sagittal CBCT image shows “tram-track” calcification of the facial artery (arrow)

Fig. 7 CBCT sialogram of the submandibular gland shows a nega- tive filling defect in the proximal portion of Wharton’s duct (arrow).

The defect suggests a minimally calcified sialolith (mucus plug). The

“sausage-string” appearance of the main duct is typical of sialodochi- tis

(4)

often appearing as “ground-glass” opacities (resembling glass that has been ground or etched to create a roughened, nontransparent surface) with ill-defined borders blending into normal adjacent bone (Fig. 10). Bone changes associ- ated with hyperparathyroidism may show a similar pattern on a diagnostic image.

“Cotton‑wool” appearance

The late stage of Paget’s disease of bone classically pre- sents with rounded, dense, radiopaque patches of abnormal bone, creating a “cotton-wool” appearance. Florid cemento- osseous dysplasia may also present with “cotton-wool”-type radiopaque regions (Fig. 11). However, these lesions are centered above the inferior alveolar nerve canal and most commonly have a radiolucent capsule, whereas in Paget’s disease the entire mandible may display hypercementosis [16].

“Moth‑eaten” appearance

The first radiographic evidence of osteomyelitis is often a slight decrease in the density of the involved bone, with a loss of sharpness of the trabecular structure [17]. The bone resorption becomes more profound with time, resulting in ill-defined lytic areas throughout the affected bone. This pat- tern sometimes takes the form of “moth-eaten” bone (simi- lar to a piece of clothing ruined by moth larvae) (Fig. 12).

Early-to-moderate bone invasion by aggressive carcinoma often produces a permeative, or “moth-eaten,” pattern of bone destruction. Here, the overall bone density decreases, and the bone markings become indistinct.

“Floating teeth” appearance

When the jaws are affected by Langerhans cell histiocyto- sis, the change usually consists of focal alveolar bone loss resembling localized severe periodontitis [18] (Fig. 13). The alveolar lesions commonly start in the midroot region of the teeth, with bone destruction progressing in a circular

Fig. 8 Waters view shows the “hanging drop” sign of the orbital floor blowout fracture with herniation of soft tissue into the maxillary sinus (arrow). An air–fluid level is visible in the maxillary sinus (arrow- head)

Fig. 9 Langerhans cell histiocytosis. Lateral skull projection shows a well-defined, “punched-out” lesion in the parietal bone (arrow). In advanced cases, multiple lesions may enlarge and coalesce to form

“maplike” areas referred to as “geographic skull”

Fig. 10 Axial CBCT image of fibrous dysplasia shows an expansile lesion of the right mandible with the typical “ground-glass” appear- ance

(5)

manner to include a portion of the superior border of the alveolar process, giving the impression that a segment of the alveolar process has been scooped out. In some cases, destruction of the supporting alveolar bone is so severe that the teeth appear to be floating in air [19]. The periphery usu- ally appears punched-out. However, the presence of reactive marginal sclerosis indicates periodontitis.

“Bull’s‑eye” appearance

When the roots are dilacerated mesially or distally, the con- dition is clearly visible on a periapical film. However, when

the roots are dilacerated facially or lingually, the central X-ray beam passes parallel to the long axis of the dilacer- ated portion of the root. This pattern, in turn, leads to a round, radiopaque area with a central dark spot (caused by the apical foramen of the root canal), giving the appearance of a “bull’s eye” (Fig. 14). The periodontal ligamental space around this dilacerated portion may appear as a radiolucent halo encircling the radiopaque area.

“Onion‑skin” appearance

Salivary gland stones (sialoliths) are most common (80–90%) in the submandibular gland. Some of the rea- sons given for the higher incidence of sialolithiasis in the submandibular gland than in the parotid gland are the more viscous nature and higher mineral content of sub- mandibular gland secretions and the more tortuous course and uphill flow of Wharton’s duct. Radiographically, sialo- liths usually have a smooth shape. Their internal structure is most often homogeneously radiopaque with evidence of a laminated pattern, giving sialoliths an “onion-skin”

Fig. 12 Panoramic image shows the typical “moth-eaten” pattern of bone destruction, areas of rarefaction, sequestrum formation, and a periosteal reaction at the inferior border of the mandible (arrow)

Fig. 13 Panoramic radiograph of the right second molar teeth “float- ing in air” because of periodontitis. Note the reactive sclerosis sur- rounding the periodontal defect and the generalized marginal bone loss and calculus

Fig. 14 Periapical radiograph of the maxillary premolars. The root tip of the first premolar root is dilacerated in the buccolingual direc- tion so tits long axis lies along the path of the X-ray beam. Note the

“bull’s eye” appearance produced by the root canal, root tip, and peri- odontal ligamental space (arrow)

(6)

appearance (Fig. 15). Periosteal reaction consists of sev- eral parallel, concentric layers of periosteal new bone laid down between the periosteum and the outer cortex. This pattern is most commonly seen in inflammatory lesions (e.g., chronic osteomyelitis with proliferative periostitis) and rarely in tumors such as Ewing sarcoma and Langer- hans cell histiocytosis [5].

“Cookie‑bite” appearance

The term “cookie-bite” lesion was first used in the medi- cal literature by Deutsch et al. to describe a saucerized, osteolytic, cortical, metastatic lesion derived from bron- chogenic carcinoma [20]. Although “cookie-bite” metas- tasis can develop from other primary malignancies, the most common primary lesion is bronchogenic carcinoma [21] (Fig. 16). The “cookie-bite” appearance has also been observed in conjunction with osteomyelitis of the jaw [22].

“Spoke‑wheel” appearance

Central (intraosseous) hemangioma usually appears as a multilocular, expansile lesion that may be associated with displacement and resorption of adjacent teeth. When form- ing the basic multilocular pattern, however, the trabeculae may be arranged as a hub or in a spoke-of-a-wheel or hon- eycomb pattern [23]. Although the honeycomb appears to be nonspecific, the slightest hint of a “spoke-of-a-wheel”

appearance is strongly suggestive of a central hemangioma (Fig. 17).

“Doughnut” appearance

Osteoma cutis is a rare soft tissue calcification in the skin. It is usually associated with chronic acne scars. Radiographi- cally, osteoma cutis most commonly appears in the cheek as multiple, “doughnut”, or “washer-shaped”, radiopacities with radiolucent centers representing central marrow cavi- ties [24] (Fig. 18).

Fig. 15 Mandibular occlusal image shows a calcified sialolith in Wharton’s duct. Note the position and the hint at a laminated “onion- skin” internal pattern

Fig. 16 Panoramic image shows a “cookie-bite” pattern of bone destruction in the right mandible, a wide zone of transition with per- meative changes within it, and lack of sclerosis at the margin

Fig. 17 Hemangioma of the right mandible. Panoramic radiograph shows the lesion with coarse trabeculae radiating from a common center in a manner roughly resembling the spokes of a wheel. Dark spaces between trabeculae are blood cavities

(7)

“Beaten copper” appearance

The “beaten copper” appearance refers to prominent cranial markings seen on skull radiographs. These markings are thought to correspond to the gyral pattern of the growing brain and are generally considered a normal finding in chil- dren. A diffuse “beaten copper” appearance, however, has been shown to be related to elevated intracranial pressure from the growing brain in patients with premature cranio- synostosis [25]. These markings may appear as multiple radiolucent areas that resemble hammered copper (Fig. 19).

phytosis (projections of bone formation at the periphery of the articulating surfaces), and subchondral degeneration.

Flattening and osteophyte formation results in “beaking”

at the anterior aspect of the condyle [26] (Fig. 20).

Conclusion

Radiology students as well as practicing dental clinicians may benefit from becoming familiar with the classic signs observed during oral and maxillofacial imaging. The author believes that using this simplified, pattern-based approach not only helps narrow the differential diagnosis, it may guide management by suggesting the appropriate use of additional imaging while avoiding unnecessary testing.

Fig. 18 Osteoma cutis. Bitewing image shows faint doughnut-shaped radiopacities in the cheek

Fig. 19 Lateral cephalometric view shows convolutional markings (“beaten-copper” appearance) in a patient without a known history of craniosynostosis

Fig. 20 Panoramic radiograph shows bilateral flattening osteophyte formation at the anterior aspect of the condyles giving a “bird’s beak”

appearance

(8)

Compliance with ethical standards

Conflict of interest Galal Omami declares that he has no conflict of interest.

Research involving human and/or animal rights This article does not contain any studies with human or animal subjects performed by any of the authors.

References

1. Kim SG, Jang HS. Ameloblastoma: a clinical, radiographic, and histopathologic analysis of 71 cases. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2001;91:649–53.

2. Kruse-Lösler B, Diallo R, Gaertner C, Mischke KL, Joos U, Kleinheinz J. Central giant cell granuloma of the jaws: a clinical, radiologic and histopathologic study of 26 cases. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2006;101:346–54.

3. Bennett JH, Thomas G, Evans AW, Speight PM. Osteosarcoma of the jaws: a 30-year retrospective review. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2000;90:323–32.

4. Wang S, Shi H, Yu Q. Osteosarcoma of the jaws: demographic and CT imaging features. Dentomaxillofac Radiol. 2012;41:37–42.

5. Ida M, Tetsumura A, Kurabayashi T, Sasaki T. Periosteal new bone formation in the jaws: a computed tomographic study. Den- tomaxillofac Radiol. 1997;26:169–76.

6. Kawai N, Wakasa T, Asaumi J, Kishi K. A radiographic study on resorption of tooth root associated with malignant tumors. Oral Radiol. 2000;16:55–65.

7. Garrington GE, Scofield HH, Cornyn J, Hooker SP. Osteosarcoma of the jaws: analysis of 56 cases. Cancer. 1967;20:377–91.

8. Gynther GW, Tronje G, Holmlund AB. Radiographic changes in the temporomandibular joint in patients with generalized osteoar- thritis and rheumatoid arthritis. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 1996;81:613–8.

9. Lanzer P, Boehm M, Sorribas V, Thiriet M, Janzen J, Zeller T, et al. Medial vascular calcification revisited: review and perspec- tives. Eur Heart J. 2014;35:1515–25.

10. Amann K. Media calcification and intima calcification are dis- tinct entities in chronic kidney disease. Clin J Am Soc Nephrol.

2008;3:1599–605.

11. Yousem DM, Kraut MA, Chalian AA. Major salivary gland imag- ing. Radiographics. 2000;216:19–29.

12. Takagi Y, Sumi M, Van Cauteren M, Nakamura T. Fast and high- resolution MR sialography using a small surface coil. J Magn Reson Imaging. 2005;22:29–37.

13. Lee HJ, Jilani M, Frohman L, Baker S. CT of orbital trauma.

Emerg Radiol. 2004;10:168–72.

14. Witt C, Borges AC, Klein K, Neumann HJ. Radiographic mani- festations of multiple myeloma in the mandible: a retrospective study of 77 patients. J Oral Maxillofac Surg. 1997;55:450–3.

15. Ricalde P, Magliocca KR, Lee JS. Craniofacial fibrous dysplasia.

Oral Maxillofacial Surg Clin North Am. 2012;24:427–41.

16. White SC, Pharoah MJ. Other bone diseases. In: White SC, Pharoah MJ, editors. Oral radiology: principles and interpreta- tion. 7th ed. St. Louis: Elsevier; 2013. pp. 402–25.

17. Schuknecht B, Valavanis A. Osteomyelitis of the mandible. Neu- roimaging Clin N Am. 2003;13:605–18.

18. Kilborn TN, Teh J, Goodman TR. Paediatric manifestations of Langerhans cell histiocytosis: a review of the clinical and radio- logical findings. Clin Radiol. 2003;58:269–78.

19. Dagenais M, Pharoah MJ, Sikorski PA. The radiographic char- acteristics of histiocytosis X: a study of 29 cases that involve the jaws. Oral Surg Oral Med Oral Pathol Oral Radiol Endod.

1992;74:230–6.

20. Deutsch A, Resnick D. Eccentric cortical metastases to the skel- eton from bronchogenic carcinoma. Radiology. 1980;137:49–52.

21. Hendrix RW, Rogers LF, Davis TM Jr. Cortical bone metastases.

Radiology. 1991;181:409–13.

22. Omami G. “Cookie-bite” lesion of the mandible. J Am Dent Assoc. 2017;148:530–4.

23. Zlotogorski A, Buchner A, Kaffe I, Schwartz-Arad D. Radiologi- cal features of central haemangioma of the jaws. Dentomaxillofac Radiol. 2005;34:292–6.

24. Shigehara H, Honda Y, Kishi K, Sugimoto T. Radiographic and morphologic studies of multiple miliary osteomas of cadaver skin. Oral Surg Oral Med Oral Pathol Oral Radiol Endod.

1998;86:121–5.

25. Tuite GF, Evanson J, Chong WK, Thompson DN, Harkness WF, Jones BM, et al. The beaten copper cranium: a correlation between intracranial pressure, cranial radiographs, and computed tomographic scans in children with craniosynostosis. Neurosur- gery. 1996;39:691–9.

26. Larheim TA, Abrahamsson AK, Kristensen M, Arvidsson LZ.

Temporomandibular joint diagnostics using CBCT. Dentomaxil- lofac Radiol. 2015;44:20140235.

參考文獻

相關文件

Loss of vascular content, increase of fat in the bone marrow cavity, and fibrosis showed a linear relation with time after radiation and were considered the end stage of

Animal or vegetable fats and oils and their fractiors, boiled, oxidised, dehydrated, sulphurised, blown, polymerised by heat in vacuum or in inert gas or otherwise chemically

Milk and cream, in powder, granule or other solid form, of a fat content, by weight, exceeding 1.5%, not containing added sugar or other sweetening matter.

For 5 to be the precise limit of f(x) as x approaches 3, we must not only be able to bring the difference between f(x) and 5 below each of these three numbers; we must be able

[This function is named after the electrical engineer Oliver Heaviside (1850–1925) and can be used to describe an electric current that is switched on at time t = 0.] Its graph

Consistent with the negative price of systematic volatility risk found by the option pricing studies, we see lower average raw returns, CAPM alphas, and FF-3 alphas with higher

You are given the wavelength and total energy of a light pulse and asked to find the number of photons it

Wang, Solving pseudomonotone variational inequalities and pseudocon- vex optimization problems using the projection neural network, IEEE Transactions on Neural Networks 17