Magnetic resonance imaging in the evaluation of periosteal reactions

Abstracts

O objetivo deste ensaio iconográfico é estimular a avaliação cuidadosa das reações periosteais nas imagens de ressonância magnética. A abordagem inicial das lesões ósseas é realizada por meio das radiografias simples e pela avaliação destas se faz a classificação das reações periosteais em subtipos clássicos. Embora a ressonância magnética seja considerada o padrão ouro para o estadiamento regional das neoplasias ósseas, seu uso no estudo das reações periosteais relacionadas às lesões ósseas focais tem sido relativamente pouco enfatizado. A revisão da literatura evidencia um modelo experimental animal de osteomielite que sugere que a ressonância magnética seja superior às outras técnicas de imagem na identificação precoce das reações periosteais. Outro estudo encontrado na literatura sugere boa correlação entre as radiografias simples e as imagens de ressonância magnética na identificação e na classificação das reações periosteais no osteossarcoma. Neste ensaio foram ilustrados casos de reações periosteais observadas pela ressonância magnética, correlacionado-as com as radiografias convencionais ou com outros métodos de diagnóstico por imagem.

Periostite; Tumores ósseos; Imagem por ressonância magnética

ICONOGRAPHIC ESSAY

Magnetic resonance imaging in the evaluation of periosteal reactions^*

Marcello Henrique Nogueira-Barbosa^I; José Luiz de Sá^II; Clóvis Simão Trad^III; Rodrigo Cecílio Vieira de Oliveira^IV; Jorge Elias Júnior^I; Edgard Eduard Engel^V; Marcelo Novelino Simão^VI; Valdair Francisco Muglia^I

^IPhDs., Professors at Centro de Ciências das Imagens e Física Médica (CCIFM), Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo (FMRP-USP), Ribeirão Preto, SP, Brazil

^IIMD, Resident at Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo (HCFMRP-USP), Ribeirão Preto, SP, Brazil

^IIIPhD, Volunteer Faculty at Centro de Ciências das Imagens e Física Médica (CCIFM), Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo (FMRP-USP), Ribeirão Preto, SP, Brazil

^IVMD, Radiologist, Clínica de Diagnóstico por Imagem Tomoson, Araçatuba, SP, Brazil

^VPhD, Professor, Department of Locomotor Apparatus Biomechanics, Medicine and Rehabilitation, Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo (FMRP-USP), Ribeirão Preto, SP, Brazil

^VIMaster, Physician Assistant at the Service of Radiodiagnosis, Centro de Ciências das Imagens e Física Médica (CCIFM), Hospital das Clínicas, Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo (HCFMRP-USP), Ribeirão Preto, SP, Brazil

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ABSTRACT

The objective of the present essay was to encourage a careful evaluation of periosteal reactions on magnetic resonance images. The initial approach to bone lesions is made by conventional radiography and, based on the imaging findings, periosteal reactions are classified into classical subtypes. Although magnetic resonance imaging is considered as the gold standard for local staging of bone tumors, the utilization of such method in the study of periosteal reactions related to focal bone lesions has been poorly emphasized, with relatively few studies approaching this subject. The literature review revealed a study describing an experimental animal model of osteomyelitis suggesting that magnetic resonance imaging is superior to other imaging methods in the early identification of periosteal reactions. Another study has suggested a good correlation between conventional radiography and magnetic resonance imaging in the identification and classification of periosteal reactions in cases of osteosarcoma. The present essay illustrates cases of periosteal reactions observed at magnetic resonance imaging in correlation with findings of conventional radiography or other imaging methods.

Keywords: Periostitis; Bone neoplasm; Magnetic resonance imaging.

INTRODUCTION

The initial approach to bone lesions is based on the evaluation of conventional radiographic images. The classic radiological semiology of focal bone lesions includes the identification and characterization of periosteal reactions. Usually, periosteal reactions are classified into some classic subtypes and the identification of such subtypes may occasionally be useful and suggest the presence of a specific disease or neoplasm^(1,2). Generally, processes involving intense activity or fast progression result in more aggressive periosteal reactions, and indolent processes result in non-aggressive presentations^(1,2). Interrupted periosteal reactions indicate the presence of biologically aggressive processes. However, there is a considerable overlap of imaging findings and the simple classification of periosteal reaction does not sufficiently define the nature or aggressiveness of the lesion⁽³⁾.

Although magnetic resonance imaging (MRI) is considered as the best method for local staging of musculoskeletal lesions^{(4- 6)}, it is possible that the MRI capability of evaluating periosteal alterations is being underestimated. For example, a recent published review about periosteal reactions intended to education of medical residents in imaging diagnosis does not include a specific discussion on the evaluation of periosteal reactions by MRI⁽¹⁾.

The present iconographic essay is aimed at stimulating a careful evaluation of periosteal reactions at MRI. Cases os periosteal reactions observed by MRI are illustrated and correlated with conventional radiography and other imaging diagnosis methods.

PERIOSTEAL REACTION

Figure 1 demonstrates a normal periosteum identified on MRI images. Frequently, the normal periosteum is not even individualized by MRI images. In the event of an insult that induces periosteal reaction, vascular proliferation and thickening of the normal periosteum are observed as a response to a triggering factor. The causes of periosteal reaction are extremely varied and a comprehensive list should include tumors, infection, trauma, drugs, venous stasis, congenital osteometabolic disorders and arthritis.

The morphology of periosteal reaction reflects the intensity, duration and aggressiveness of the triggering agent^(1,2). The periosteal reaction becomes visible at conventional radiography only in the presence of a certain degree of mineralization that takes about 10-21 days to be achieved⁽²⁾.

TYPES OF PERIOSTEAL REACTION

Solid

Solid periosteal reaction represents a continuous bone neoformation attached to the external cortical surface, typically occurring as a response to indolent and benign processes^(1,2). Solid periosteal reaction can be thin (Figures 2 and 3) but, sporadically, chronic processes may cause thicker solid reactions (Figure 4).

Lamellar or multilamellar

Multilamellar periosteal reaction (Figure 5), also denominated "onion skin" is caused by deposition of concentric, sheetlike layers of mineralized periosteal new bone, separated by vascular dilatation and loose connective tissue^(1-3). In cases of association with malignant tumors, the spaces between the layers may become secondarily infiltrated by malignant cells. Possible associations include: Ewing sarcoma, osteosarcoma, osteomyelitis and aneurysmal bone cyst, among others⁽³⁾.

Spiculated pattern, arising perpendicular to the bone cortex

Spiculated periosteal reaction corresponds to thin spicules arranged perpendicular to the bone cortex (Figure 6). Such spicules are not neoplastic and originate from the ossification along periosteal vascular channels and fibrous bands (Shapey's fibers) stretched away from the bone cortex^(1-3). The loose areolar tissue between spicules may be later replaced by a tumor or other tissues.

Sun ray pattern

In the divergent spiculated or "sun ray" periosteal reaction, the spicules extend into an epicenter in the bone tissue (Figures 7 and 8). Sun ray periosteal reaction is generally perceived as a sign of malignancy and is frequently associated with osteosarcoma^(1,3), although it may be observed in benign lesions such as osteoblastomas and hemangiomas⁽³⁾.

Codman's triangle

Codman's triangle is the interrupted version of the lamellar and multilamellar periosteal reaction (Figures 9 and 10). Generally, the region of the Codman's triangle is tumor-free, but may be secondarily infiltrated⁽⁷⁾. This type of periosteal reaction was firstly described in cases of osteosarcoma, but it can be observed in other primary malignant tumors or bone metastases in osteomyelitis, in trauma, and in benign, but active tumors, such as aneurysmal bone cysts^(1,3).

DISCUSSION

The prevalence of the different types ofperiosteal reaction in each type of bone tumor is relatively poorly documented in the literature⁽³⁾. Notwithstanding, the description of the above described periostealreaction subtypes is a usual practice in conventional radiological reports. Few descriptions are found in the literature about MRI in the study of periosteal reactions^(8-10). An experimental study has evaluated the most effective method for identifying periostitis following induction of leg bone infection in rabbits, comparing conventional radiology, contrast-enhanced computed tomography and MRI, using histology as the gold standard⁽⁸⁾. In such study, MRI was considered as the best method in the identification of periosteal elevation, being capable of identifying periostitis even in the absence of ossification. Two cases of false-positive result were observed with MRI.

Another study has blindly compared conventional radiology and MRI as to the presence and classification of periosteal reactions in osteosarcomas, observing a good correlation between both methods⁽¹⁰⁾.

CONCLUSION

The semiological patterns of periosteal reactions observed at conventional radiography can be extrapolated to magnetic resonance imaging. Considering the relevance of the findings, the identification and characterization of periosteal reaction at MRI should be stimulated.

Acknowledgements

To Fundação de Apoio ao Ensino, Pesquisa e Assistência (FAEPA) - Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo, for the financial support provided under Nbr.481/2009 for the development of the present study.

REFERENCES

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• 7. Codman EA. Registry of bone sarcoma; part I, twenty-five criteria for establishing diagnosis of osteogenic sarcoma; part II, 13 registered cases of 5 year cures analyzed according to these criteria. Surg Gynecol Obstet. 1926;42:381-93.
• 8. Spaeth HJ, Chandnani VP, Beltran J, et al. Magnetic resonance imaging detection of early experimental periostitis. Comparison of magnetic resonance imaging, computed tomography, and plain radiography with histopathologic correlation. Invest Radiol. 1991;26:304-8.
• 9. Greenfield GB, Warren DL, Clark RA. MR imaging of periosteal and cortical changes of bone. Radiographics. 1991;11:611-23.
• 10. Dosdá R, Martí-Bonmatí L, Menor F, et al. Comparison of plain radiographs and magnetic resonance images in the evaluation of periosteal reaction and osteoid matrix in osteosarcomas. MAGMA. 1999;9:72-80.

*

Trabalho realizado no Serviço de Radiodiagnóstico do Centro de Ciências das Imagens e Física Médica (CCIFM) do Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo (HCFMRP-USP), Ribeirão Preto, SP, Brasil.

Publication Dates

• Publication in this collection
  16 Sept 2010
• Date of issue
  Aug 2010

History

• Received
  11 Feb 2010
• Accepted
  26 Mar 2010