Classical signs in oral and maxillofacial radiology.pptx

Oral and maxillofacial imaging is no exception. As a specialty that deals with uncommon lesions and complex
anatomy, both students and practicing dental clinicians
may benefit from this simplistic, pattern-based approach.
This presentation describes a compendium of the classic signs in oral and maxillofacial radiology.

1. CLASSIC SIGNS IN ORAL AND MAXILLOFACIAL RADIOLOGY Presented by Dr. Rahul Srivastava Professor Rama Dental College Hospital & Research Centre, Kanpur

2. “Soap bubble and honeycomb” appearances Soap bubble is reserved for lesions consisting of several circular compartments that vary in size and usually appear to overlap somewhat. Honeycomb applies to lesions whose compartments are small and tend to be uniform in size.

3. “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.

4. 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). Generally, the compartments are large in the posterior mandible and small in the anterior mandible.

5. Soap bubble pattern may also be observed in odontogenic keratocysts and giant cell granulomas . Cropped Panoramic view of the lesion shows numerous small compartments (“honeycomb” pattern) Cropped Panoramic image shows, multilocular “soap bubble” lesions

6. Sun ray / sunburst appearance If the lesion grows rapidly but steadily, the periosteum will not have enough time to lay down thin shell of bone, and in such cases, the tiny fibers that connect the periosteum to the bone ( Sharpey’s fibers) become stretched out perpendicular to the bone. When these fibers ossify, they produce a pattern sometimes called “sunburst” periosteal reaction.

7. Lesions exhibit bone production with a “sunray” appearance: Chondrosarcomas . Fibrosarcomas Metastatic breast and prostate tumors. Osteosarcoma . Hemangioma . Osteoblastoma .

8. Osteosarcoma of the mandible. Cross-sectional cone-beam computed tomography (CBCT) image shows an exuberant periosteal reaction with a “sunburst” pattern

9. “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”.

10. In the absence of generalized periodontitis , widening of the periodontal ligament space that involves one or several adjacent teeth (characteristically limited to one side of the root) could be an early sign of malignancy ( Garrington’s sign)

11. Increased bone density 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

12. “Sharpened pencil” appearance Rheumatoid arthritis is characterized by synovial proliferation ( 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 posterior condylar surfaces, resulting in a small, pointed condyle in a large fossa (“sharpened pencil” appearance) .

13. 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 .

14. “Tram‑ track ” appearance Monckeberg’s medial vascular calcification (arteriosclerosis) 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.

15. This type of calcification is most frequently seen in patients with diabetes mellitus or chronic renal failure. Radiographically , the calcified vessel appears as a parallel pair of thin, radiopaque lines that outline the affected vessel. It is described as having a “ tramtrack ” or “pipe stem” appearance

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

17. “Sausage‑ string ” appearance Sialodochitis results in dilation of the involved duct secondary to distal 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.

18. “Hanging drop” appearance The blowout orbital wall fracture results from a direct blow to the orbit. The force of the blow is transmitted to the orbital walls, among which the floor is most susceptible.

19. The classic “hanging drop” appearance of the herniated orbital content is clearly seen on a radiographic Waters’ view or on a coronal computed tomographic (CT) image, as is the “trapdoor” appearance of the displaced orbital floor.

20. 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 (arrowhead)

21. “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 surrounding bone has a normal appearance up to the edge of the hole.

22. “Punched-out” lesions are typically indicative of: Multiple myeloma. Langerhans cell histiocytosis . Punched out radiolucency

23. “Ground‑ glass ” appearance The radiological features of fibrous dysplasia vary considerably depending on the maturity of the lesion. In the early stage, fibrous dysplasia appears as a unilocular or multilocular radiolucency with ill-defined or welldefined borders.

24. In the middle stage, radiopaque tissue appears in the radiolucent structure. In the mature stage, the internal structure has a granular, radiopaque pattern 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.

25. Evident in cases of fibrous dysplasia, paget’s disease, hyperpararthyroidism and ossifying fibroma . Ground glass appearance in the case of ossifying fibroma on maxillary tuberosity region

26. “Cotton‑ wool ” appearance The late stage of Paget’s disease of bone classically presents with rounded, dense, radiopaque patches of abnormal bone, creating a “cotton-wool” appearance. Florid cementoosseous dysplasia may also present with “cotton-wool”-type radiopaque regions

27. “Cotton‑ wool ” appearance

28. “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. The bone resorption becomes more profound with time, resulting in ill-defined lytic areas throughout the affected bone.

29. This pattern sometimes takes the form of “moth-eaten” bone (similar to a piece of clothing ruined by moth larvae). Also noticed in early stages of osteosarcoma , squamous cell carcinoma,osteoradionecrosis , leukemia, malignant lymphoma.

30. Typical “moth-eaten” pattern of bone destruction, areas of rarefaction, sequestrum formation and a periosteal reaction at the inferior border of the mandible (arrow)

31. “Floating teeth” appearance It is a result of alveolar bone destruction around the root of the teeth giving the appearance of a floating tooth . Floating teeth appearance

32. Lesions have more relationship with floating teeth appearance: Aggressive periodontitis , Langerhans histiocytosis , Burkitt’s lymphoma, multiple myeloma, Metastatic tumors, Primary intraosseous carcinoma ( intraosseous squamous cell carcinoma), Ewing’s sarcoma, Hyperparathyroidism, and Cherubism .

33. “Bull’s‑eye” appearance When the roots are dilacerated facially or lingually , the central X-ray beam passes parallel to the long axis of the dilacerated 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”.

34. The root tip of the first premolar root is dilacerated in the buccolingual direction so tits long axis lies along the path of the X-ray beam. “Bull’s eye” appearance produced by the root canal, root tip, and periodontal ligamental space.

35. “Onion‑ skin ” appearance Onion skin appearance is due to lamellated periosteal reaction where multiple concentric layers of new bone are laid down. Radiographically , sialoliths usually have a smooth shape. Their internal structure is most often homogeneously radiopaque with evidence of a laminated pattern, giving sialoliths an “onion-skin”

36. 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 Langerhans cell histiocytosis .

37. Mandibular occlusal image shows a calcified sialolith in Wharton’s duct. Note the position and the hint at a laminated “onionskin” internal pattern. Mandibular occlusal image shows laminated “onionskin” pattern in case of proliferative periostitis of Garre .

38. “ Cookie‑bite ” appearance The term “cookie-bite” lesion was first used in the medical literature by Deutsch et al. to describe a saucerized , osteolytic , cortical, metastatic lesion derived from bronchogenic carcinoma. The “cookie-bite” appearance has also been observed in conjunction with osteomyelitis of the jaw

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

40. “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 forming the basic multilocular pattern, however, the trabeculae may be arranged as a hub or in a spoke-of-a-wheel or honeycomb pattern.

41. 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

42. “Doughnut” appearance Osteoma cutis is a rare soft tissue calcification in the skin. It is usually associated with chronic acne scars. Radiographically , osteoma cutis most commonly appears in the cheek as multiple, “doughnut”, or “washer-shaped”, radiopacities with radiolucent centers representing central marrow cavities

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

44. “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 children.

45. A diffuse “beaten copper” appearance, however, has been shown to be related to elevated intracranial pressure from the growing brain in patients with premature craniosynostosis . These markings may appear as multiple radiolucent areas that resemble hammered copper

46. Lateral cephalogram showing copper beaten appearance on skull.

47. “Bird’s beak” appearance Degenerative joint disease, also known as osteoarthritis and osteoarthrosis , is a non-inflammatory disease characterized by the breakdown of the articular cartilage leading to eventual degeneration of the underlying bone.

48. Degenerative changes of the joint include flattening and irregularities of the articular surfaces, osteophytosis (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 .

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

50. Codman’s triangle A triangular area of new subperiosteal bone which is formed when a tumour raises the periosteum away from the bone. A Codman triangle is found as a pseudo triangle on radiograph of normal bone.

51. A two-sided appearance of the triangle is due to a tumour which is growing at a faster rate than the normal growth of the periosteum hence tearing of periosteum occurs which in turn provides ossification on the second edge of the triangle. Codman’s triangle is evident in alveolar bone carcinoma, osteogenic sarcoma, Ewing’s sarcoma, etc.

52. Codman’s triangle

53. Hair on end appearance It is due to the periosteal reaction which appears as a perpendicular trabeculations along the skull vault by marrow hyperplasia. According to the degree of hyperplasia the bone changes. Evident in sickle cell anemia and thalassemia

54. Hair on end appearance

55. Snow Driven appearance Radiologically , CEOT is characterized by unilocular or multilocular radiolucency that often exhibits mixed radiographic feature (65%) due to the presence of scattered flecks of calcifications, often produce a typical “snow driven’’ appearance.

56. Presence of a radiopaque mass in the center of the lesion (black arrow) with radiopaque streaks has the appearance of “driven snow”.

57. Balloon like or peripheral egg shell appearance Radiopacity is most commonly seen on the periphery of the expanded cortex than inside of the expanded border. Xray beam is more attenuated in the cortical bone which is not thicker on the cortex than rest of the area because of the longer path length of photons through the bony cortex on the periphery.

58. In radiograph, these circular, fluid-filled shaped structure gives a balloon like appearance. This type of balloon like appearance is most commonly seen in follicular cysts. Balloon like appearance

59. Downward bowing This radiographic pattern is due to the lesion that invade to the inferior border of the mandible when their size reaches a limit. It appears as a round tumour mass due to the centrifugal growth pattern and thus equal expansion can be observed in all directions.

60. Downward bowing appearance is commonly seen in cemento -ossifying fibroma and ameloblastoma Downward bowing in a patient with ameloblastoma

61. Ghost teeth Teeth in a region or quadrant of maxilla or mandible are affected to the extent that they exhibit short roots, wide open apical foramen and large pulp chamber, the thinness and poor mineralisation qualities of the enamel and dentine layers have given rise to a faint radiolucent image, hence the term "Ghost teeth".

62. Ghost teeth is seen in case of regional odontodysplasia Ghost teeth appearance

63. Heart shaped radiolucency Anterior nasal spine overlaps cystic radiolucency in the maxillary central incisor region thus giving a heart shaped radiographic pattern. It is a characteristic sign for nasopalatine cyst.

64. Heart shaped radioucency

65. Mottled appearance Due to uneven spots it is named as mottled appearance. Radiographically it appears as a mixed lesion with patchy radiolucency and radiopacities are found interspersing between lucent areas. Evident in fibrous dysplasia, ossifying fibroma , Paget’s disease, etc.

66. Mottled appearance

67. Step ladder appearance The step ladder appearance occurs due to the horizontal trabeculations of medullary bone of jaws. Most commonly observed in sickle cell anemia and also in normal mandibular alveolar bone.

68. Step ladder appearance

69. Tennis racket appearance It is a radiographic appearance present in radiolucent multilocular lesions comprising of angular compartments which results from the development of straight septa. Tennis racket appearance is the characteristic sign of odontogenic myxoma .

70. Tennis racket appearance

71. Pear-shaped or tear shaped appearance Radiographic picture is of globulomaxillary cyst is inverted pear-shaped or tear shaped, with well defined radiolucency between the separated roots of lateral incisor and canine.

72. Pear-shaped or tear shaped appearance

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