role of mri in diagnosis of benign and malignant bone and soft tissue tumours

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Role of MRI in diagnosis Role of MRI in diagnosis of benign and malignant of benign and malignant bone and soft tissue bone and soft tissue tumours tumours John-Henry Corbett Department of Radiology University of the Free State 05/2011

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Role of MRI in diagnosis of benign and malignant bone and soft tissue tumours. John-Henry Corbett Department of Radiology University of the Free State 05/2011. C onventional r adiographs remain the initial imaging examination for bone and some soft tissue tumours - PowerPoint PPT Presentation

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Page 1: Role of MRI in diagnosis of benign and malignant bone and soft tissue tumours

Role of MRI in diagnosis of benign Role of MRI in diagnosis of benign and malignant bone and soft tissue and malignant bone and soft tissue

tumourstumours

John-Henry CorbettDepartment of Radiology

University of the Free State05/2011

Page 2: Role of MRI in diagnosis of benign and malignant bone and soft tissue tumours

• CConventional rradiographs remain the initialinitial imaging examination for bone and some soft tissue tumours

• XR is invariably the most diagnostic– Best for establishing a differential diagnosisdifferential diagnosis– Best in assesing activity of the lesion

• Benign vs malignantBenign vs malignant

• Other imaging modalities ( eg. MRI ) are superior in stagingstaging musculoskeletal neoplasms

Page 3: Role of MRI in diagnosis of benign and malignant bone and soft tissue tumours

• Major advantages of MRI for musculoskeletal imaging– Excellent soft tissue contrast resolution– Multiplanar imaging capabilities– Various available contrast agents

• Powerful imaging modality for abnormalities of– Fat, muscles, nerves, bone and bone marrow

• Effective for use in– Neoplasms of tissues mentioned above– Response of neoplasms to neoadjuvant / posoperative

chemotherapy and/or radiotherapy– Residual and/or recurrent tumour after surgery– Congenital and developmental musculoskeletal

abnormalities– Traumatic lesions– Haemorrhage– Ischaemia / infarction of bone marrow / muscles / fat– Infectious and non-infectious inflammatory diseases

Page 4: Role of MRI in diagnosis of benign and malignant bone and soft tissue tumours

• Longitudinal bone growth occurs by enchondral bone formation– A calcified cartilaginous matrix at the growth/physeal plate at the growth/physeal plate is

remodelled into bone

• Physeal plate contains four parallel zones perpendicular to the long axis of the bone

•Active cartilage cell division and maturation in the proliferating and hypertrophic zones

•Ostoid matrix formation and mineralization occurs in the ossification zone

•Resting, Proliferating and Hypertrophic zones •Radiolucent on XR / CT•High signal on T2WI

•Ossification zone•Mineralized bone on XR / CT•Low signal on T2WI

Page 5: Role of MRI in diagnosis of benign and malignant bone and soft tissue tumours

• Axial bone growth occurs directly from the periosteum periosteum – E.g.: Diameter of long bones, facial bones

• Outer fibrous layer and inner cellular layer (cambrium – osteoblastic activity)

• Periosteum is loosely attached to the cortex of bones in children and firmly in adults

• Periosteum is low signal on T1WI & T2WI• Reactivation of periosteum in adults

– Trauma, infection or neoplasm• MRI can demonstrate periosteal elevation as well

as subperiosteal abnormalities such as tumour, pus or haemorrhage

Page 6: Role of MRI in diagnosis of benign and malignant bone and soft tissue tumours

• MRI signal in medullary portion of bone– Red (hematopoietic) marrowRed (hematopoietic) marrow

• 40% fat , 40% water & 20% protein• Intermediate T1WI signal – lower than subcut fat• Intermediate T2WI signal – similar to muscle• Predominant marrow in early childhood• Adults : Spine, flat bones, skull, proximal femur &

humerus– Yellow (hematopoietically inactive) marrowYellow (hematopoietically inactive) marrow

• 80% fat, 15% water & 5% protein• Similar signal to subcutaneous fat on T1WI & T2WI • Later in childhood – progressive conversion of red to

yellow marrow– Hands and feet – Distal long bones : diaphyseal regions in the first decade

Page 7: Role of MRI in diagnosis of benign and malignant bone and soft tissue tumours

• Most pathological processes pathological processes increase the T1 and T2 relaxation coefficients of involved tissue

• Leads to ↓T1 signal ↓T1 signal and ↑T2 signal ↑T2 signal compared to surrounding normal tissue– Includes : ischaemia, infarction, inflammation,

neoplasm– Haemorrhage : variable appearance according to

age

Page 8: Role of MRI in diagnosis of benign and malignant bone and soft tissue tumours

Imaging evaluation of bone and soft Imaging evaluation of bone and soft tissue tumourstissue tumours

• On XR most bone tumours are radiolucent• Osteolytic lesions may not be visible on XR

until there is 30-50% loss of mineralization• MRI can detect marrow based tumours before

they are evident on XR• MRI can also further characterize lesions with

regards to extent and soft tissue extension

Page 9: Role of MRI in diagnosis of benign and malignant bone and soft tissue tumours

• Features used to characterize bone and other tumours on XRXR– Lesion location

• Epiphyseal / metaphyseal / diaphyseal • Cortical / intramedullary / eccentric / central

– Lesion size– Lesion density

• Radiolucent / sclerotic / presence of matrix mineralization– Margins

• Well defined geographic ± sclerotic borders / poorly defined• Moth eaten / permeative radiolucent patterns

– Presence of cortical destruction • ± Extra osseous tumour extension

– Presence of periosteal reaction• Interrupted vs non-interrupted pattern• Lamellated / onion skin appearance• Perpendicular-, sunburst pattern• Codman triangles

Page 10: Role of MRI in diagnosis of benign and malignant bone and soft tissue tumours

• Features used to characterize bone and soft tissue tumours on MRIMRI– Lesion location– Lesion size– Margins

• Well-defined geographic ± low signal margins vs poorly defined

– Signal of the lesion on• T1WI• PDWI with and/or without fat saturation• T2WI with and/or without fat saturation• STIR images

– Enhancement after IV Gadolineum based contrast– Presence of cortical destruction

Page 11: Role of MRI in diagnosis of benign and malignant bone and soft tissue tumours

• T1WIT1WI– Good contrast for identification of marrow , cortical and

soft-tissue involvemement– Differentiation between fat (↑) and tumour (↓)– Definition of muscle plains and anatomic compartments– Longitudinal extent of the tumour can be seen on coronal

or sagital T1WI• Gadolinium enhanced T1WIGadolinium enhanced T1WI

– Better characterize osseous & soft tissue involvement– Non-enhancing regions of tumour regarded as tumour

necrosis– Useful for differentiating

• Peritumoural oedema from underlying tumour• Recurrent tumour from scar / fibrosis

– Dynamic contrast enhanced imaging has been used to determine response to chemotherapy

• Good response shows reduced enhancement• Short time intervals should be used (similar in late phase

enhancement)

Page 12: Role of MRI in diagnosis of benign and malignant bone and soft tissue tumours

• T2WIT2WI– Distinguish muscle from tumour– Increase diagnostic specificity of marrow

infiltration• Seen as low signal on T1WI

• Proton density- / T2WI- with fatsat Proton density- / T2WI- with fatsat or STIRSTIR– Lesion iso-intense to adjacent tissue

• T1WI, T2WI and T2WI fatsat / STIR– Axial images to delineate the relationship of the

tumour to adjacent neurovascular structures and compartments

• MR spectroscopy not routinely used

Page 13: Role of MRI in diagnosis of benign and malignant bone and soft tissue tumours

• Not possible to distinguish benign from Not possible to distinguish benign from malignant malignant lesions of bone and soft tissue on on MRI signal characteristics aloneMRI signal characteristics alone

• Malignant lesions tend to be more extensive– Involvement of cortex, marrow and soft tissues– Involvement of the neurovascular bundle

• Perform MRI prior to biopsies to avoid postsurgical inflammation and oedema– Prolong T2 relaxation time of uninvolved tissues

• Muscle oedema is non-specific – Associated with trauma, infection & vascular

insults

Page 14: Role of MRI in diagnosis of benign and malignant bone and soft tissue tumours

• On T1WI ↑ signal in surrounding muscles can be seen in atrophy with fatty infiltration oror neuromuscular disorders– Not to be mistaken for tumour

• Marrow inhomogeneity Marrow inhomogeneity – Red to yellow marrow conversion– Especially middle aged obese women with

smoking history / immature skeleton– Metaphyseal or diaphyseal low signal intensity

(red marrow)• No extension over physeal scar

– ↑Signal intensity on STIR images

Page 15: Role of MRI in diagnosis of benign and malignant bone and soft tissue tumours

T1WI : Normal ↓ signal meta-diaphyseal red marrow. Epihyseal region is uniformly yellow marrow

STIR : ↑ signal red marrow

This finding of marrow inhomogeneity is considered a normal variant.

Page 16: Role of MRI in diagnosis of benign and malignant bone and soft tissue tumours

Coronal T1WI Coronal STIR

Red marrow heterogeneity in the femoral dyaphysis with no extension across the physeal scar

Page 17: Role of MRI in diagnosis of benign and malignant bone and soft tissue tumours

• Staging of bone / soft tissue tumoursStaging of bone / soft tissue tumours– MRI is the imaging modality of choice

• Should be used with conventional XR

– MRI is accurate in determining• Local extent of the tumour – intra /extra osseus• Skip metastases• Involvement of muscle compartments, joints and

neurovascular bundles• Local lymphadenopathy

– Enneking staging system Enneking staging system for bone and soft tissue tumours is most widely used

• Based on tumour grade, site and metastases• Histologic, radiologic and clinical criteria

Page 18: Role of MRI in diagnosis of benign and malignant bone and soft tissue tumours

• BenignBenign lesion are considered grade 0 (G0G0)• MalignantMalignant lesions are either

– Low grade (G1G1)– High grade (G2G2)

• Site and extent Site and extent of tumours– T0T0 : benign tumours confined in a true capsule and

anatomic compartment of origin– T1T1 : aggressive benign or malignant lesion confined to

its anatomic compartment– T2T2 : spread beyond the anatomic compartment of

origin• MetastaticMetastatic disease

– M0M0 : no metastatic disease– M1M1 : regional or distant metastases

Page 19: Role of MRI in diagnosis of benign and malignant bone and soft tissue tumours

Benign

1 Latent G0 T0 M0

2 Active G0 T0 M0

3 Aggressive G0 T0 M0-1

Malignant

Ia Low gradeIntra compartmental

G1 T1 M0

Ib Low gradeExtra compartmental

G1 T2 M0

IIa High gradeIntra compartmental

G2 T1 M0

IIb Low gradeExtra compartmental

G2 T2 M0

IIIa Low or high gradeIntra compartmental + metasteses

G1-2 T1 M1

IIIb Low or high gradeExtra compartmental + metasteses

G1-2 T2 M1

Page 20: Role of MRI in diagnosis of benign and malignant bone and soft tissue tumours
Page 21: Role of MRI in diagnosis of benign and malignant bone and soft tissue tumours

• Important points in reporting on bone tumoursreporting on bone tumours– What is the total intraosseous extent of the tumour– Is there involvement of the growth plate– Are there any “skip” metastases– Is the adjacent joint involved– What is the relationship to the neurovascular bundle

• Important points in reporting on soft tissue reporting on soft tissue tumourstumours– Anatomical location of the tumour– Its relationship to the adjacent bone– Its relationship to the neurovascular bundle– Provisional diagnosis

• Neoplastic or non-neoplastic• Benign or malignant

Page 22: Role of MRI in diagnosis of benign and malignant bone and soft tissue tumours

• Suggested series Suggested series for bone tumours bone tumours ( 3 )– Longitudinal T1WI

• Covering the whole lesion• Include the adjacent joint• Intraosseous extent and relationship to the growth plate• Extremity coil if possible

– Coronal T1WI• Body coil• Include the whole bone• Evaluation for skip metastases

– Axial T2WI with FATSAT• Relationship to the neurovascular bundle• Extremity coil if possible• Include the whole lesion

Page 23: Role of MRI in diagnosis of benign and malignant bone and soft tissue tumours

• Suggested series Suggested series for soft tissue tumours soft tissue tumours ( 4 )– Longitudinal T1WI– Longitudinal STIR– Coronal T1WI– Axial T2WI with FATSAT

Page 24: Role of MRI in diagnosis of benign and malignant bone and soft tissue tumours

• Longitudinal T2WI– Adds nothing to intraosseous staging – Both tumour (osteosarcoma) and marrow are

relatively high signal

• Standard enhanced T1WI – Have not been shown to be of value in evaluating

primary bone tumours

• Axial T1WI– Adds nothing to extraosseous staging– Tumour mostly isointense to muscle

Page 25: Role of MRI in diagnosis of benign and malignant bone and soft tissue tumours

Coronal T1W SE Coronal T1W SE image of the distal femur in a patient withosteosarcoma showing intraosseous extent.

Sagittal T1W Sagittal T1W SE image of the whole femur in a patient with distal femoral osteosarcoma. A region of reduced signal intensity in themid-diaphysis proved to be a ‘skip’ metastasis.

Page 26: Role of MRI in diagnosis of benign and malignant bone and soft tissue tumours

AxialAxial dual-echo T2T2 FSE sequence with fat saturation with fat saturation in a patient with distal femoral osteosarcoma. The relationship between extraosseous tumour and the neurovascular bundle is best demonstrated on the proton density image (right) proton density image (right) since the neurovascular bundle is isointense to muscle on the T2W sequence (left). Peritumoural oedema is also clearly distinguished from fat by the addition of fat saturation.

Page 27: Role of MRI in diagnosis of benign and malignant bone and soft tissue tumours

WHO classification of soft tissue WHO classification of soft tissue tumourstumours

Page 28: Role of MRI in diagnosis of benign and malignant bone and soft tissue tumours
Page 29: Role of MRI in diagnosis of benign and malignant bone and soft tissue tumours
Page 30: Role of MRI in diagnosis of benign and malignant bone and soft tissue tumours

WHO classification of WHO classification of bone tumoursbone tumours

Page 31: Role of MRI in diagnosis of benign and malignant bone and soft tissue tumours

Incidence of soft tissue tumoursIncidence of soft tissue tumours

Page 32: Role of MRI in diagnosis of benign and malignant bone and soft tissue tumours

Incidence of soft tissue tumoursIncidence of soft tissue tumours

Page 33: Role of MRI in diagnosis of benign and malignant bone and soft tissue tumours
Page 34: Role of MRI in diagnosis of benign and malignant bone and soft tissue tumours

ReferencesReferences• Aisen AM, Martel W, Braunstein EM et al. MRI and CT

evaluation of bone and soft-tissue tumors. American Journal of Roengenology 1986; 146:749-756.

• Kransdorf MJ & Murphey MD. Radiologic evaluation of soft-tissue masses: a current perspective. American Journal of Roengenology 2000; 175: 575-587.

• Meyers SP. MRI of bone and soft-tissue tumours and tumour-like lesions. Thieme; 2008.

• Saifuddin A, Twinn P, Emanuel R & Cannon SR. An audit of MRI for bone and soft-tissue tumours at referral centres. Clinical Radiology 2000; 55:537-541.

• Stoller DW. MRI in orthopaedics and sports medicine. 3rd Ed. Lippincott, Williams & Wilkins; 2006.