MRI of benign and malignant bone marrow lesions

MRI of benign and malignant bone marrow lesions Copenhagen 27 january 2012 Cecilia Petersen MD Dept of Neuroradiology Skane University Hospital Lund, ...
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MRI of benign and malignant bone marrow lesions Copenhagen 27 january 2012 Cecilia Petersen MD Dept of Neuroradiology Skane University Hospital Lund, Sweden

MRI of the spine is the method of choice for evaluation of • • • •

Tumors Infections Inlammatory diseases Degenerative changes

MRI will soon also replace x-ray for patients with ”ordinary low back pain”

MRI gives much more information...

…but also more accidental findings!

Malignant or benign lesions?

Normal bone marrow consists of • an osseous component • a cellular component – hematopoetic, fat and reticulum cells • a supporting system – vascular, neural and lymphatic elements

Normal conversion of bone marrow • Hematopoietic (red) marrow in the entire skeleton at birth • Conversion to fatty (yellow) marrow begins in the periphery of the skeleton • In the second decade of life marrow of long bones becomes predominantly fatty • In the late third decade the marrow reaches its mature status

By age 25 years red marrow persists in the axial skeleton, proximal humeri and proximal femur Normal variation ex. residual islands of red marrow in the long bones or focal fatty marrow within the spine © Siegel

RED and YELLOW bone marrow

© Siegel

RED and YELLOW bone marrow • RED bone marrow • hematopoetically active • 40% water, 40% fat, 20% protein • rich vascular network • present in the entire skeleton at birth

• YELLOW bone marrow • hematopoetically inactive • 15%water, 80%fat, 5% protein • sparse vascular network • conversion of red-toyellow marrow complete at age ~25

The relative proportions of fat and water affect the signal intensity of marrow at MRI

An effective combination for evaluation of bone marrow pathology:

• T1 weighted spin-echo • STIR or fat-saturation T2 weighted fast spin-echo

T1 spin-echo • Most important sequence for bone marrow MRI • The signal intensity of yellow marrow is similar to that of subcutaneous fat • Most marrow lesions similar or lower signal than that of muscle and intervertebral disc

STIR • Additive T1 and T2 contrast • Marked fat suppression • High contrast and sensitivity for most types of bone marrow pathology • Relatively long imaging time and low signal-tonoise ratio

An effective combination for evaluation of bone marrow pathology

T1 spin-echo

STIR

T2 tse • T2 tse has a limited value for lesion detection but can contribute to lesion characterization • The use of fat saturation is essential

STIR for bone marrow

T2

STIR

T1

T2

S Holtås

T2

T1

S Holltås

Cancer mam metastases

T1 Gd

Standard MR examination of spine

• Include the whole spine • 2 FOV • Sequence time ~20 min

”Lumbar spine overview”

STIR cor includes hips and SI-joints T1 sag

STIR cor

DWI?!

Still not in daily practical use…

Gadolineum?

© Siegel

Gadolineum • Not needed for standard examinations ex evaluations of metastases • Never images only with Gadolineum • Useful for evaluation of adjacent soft tissue components

1,5 or 3 T?

Pathologic disorders • Reconversion or marrow hyperplasia • Marrow infiltration • Marrow depletion • Marrow edema

Reconversion At times of demand for increased hematopoesis yellow marrow can reconvert to red marrow ex. chronic infection, anemia, heavy smoking, obesity, middle age in women and long distance running.

Marrow reconversion

© Siegel

Reconversion vs marrow infiltration

• Relatively symmetric bilaterally • Lower STIR signal than in neoplastic processes • No cortical break-through or adjacent softtissue mass

Marrow infiltration • Focal or diffuse • Replacement of normal fatty-marrow cells • Commonly due to neoplastic disease ex. metastases, leukemia and myeloma • Gaucher`s disease and mucopolysaccharidoses are ex of nonneoplastic disorders

Marrrow infiltration T1 tse

Marrow depletion • Replacement of hematopoietic elements by fat cells • Increased signal on T1 weighted images • Focal depletion occurs normally in the spine • Some bone lesions and hemangioma • Regional after radiation therapy • Diffuse depletion can be induced by drugs and aplastic anemia

Marrow depletion - hemangioma

Typical hemangiomas have increased signal on both T1and T2-weighted images © Quinn

Hemangioma

© Quinn

Focal depletion occurs often in spine

Myeloid depletion after radiation therapy of leukemia patient Increased signal on T1 W images

PNET in L2 post radiation therapy

Marrow edema • Usually focal • Decreased signal on T1 and increased signal on STIR • Nonspecific – can be a result of trauma, infection, ischemia, neoplasia etc

Marrow edema – discitis/spondylitis

T1 tse

T2tse

STIR

GdT1tse

Low lumbar pain – marrow edema in sacrum

Marrow edema – pelvic fracture

Neoplastic disorders • • • • •

Primary bone tumors Myeloma Lymphoma Leukemia Metastases

Primary bone tumors • • • • • •

Osteoblastoma Chordoma Osteochondroma Chondrosarcoma Ewing sarcoma Aneurysmal bone cyst etc

Chordoma

© The Radiology Assistant

Myeloma-Leukemia • Focal bone marrow lesions or disseminated small hypointense lesions or diffusely decreased marrow signal on T1 • Increased signal on STIR • Tend to originate in the hematopoietic marrow • Spinal compression fractures

Myeloma • Decreased signal on T1W images • Spinal compression fracture

Lymphoma • Focal or diffuse marrow involvement • Signal changes similar to other tumors • 30% of systemic lymphomas have skeletal involvement • Multiple types; can have epidural mass, intramedullar involvement etc

Lymphoma with soft tissue component. Before and after chemotherapy.

Lymphoma with diffuse marrow involvement

Metastases • Primary tumor most common in lung, breast,prostate or kidney • Hypointense on T1 W • Hyperintense on STIR • Solitary or multiple focal lesions • Posterior part of the vertebral body and pedicle often involved • Intervertebral discs generally spared • May cause pathologic fracture • May spread in the epidural space

Prostata cancer metastases

Prostata cancer metastases T1

STIR

Intervertebral discs appears bright on T1 in case of massive tumor infiltration

STIR

T1

T1Gd

Pitfalls in diagnosis of metastases

• • • •

Normal variants Compression fracture Osteomyelitis/spondylitis Marrow infarction

Normal variants

Irregular fatty marrow

Normal variants

Hemangiomas can also have epiduralcomponents

© Quinn

One or two metastases?

One or two metastases? CT can be useful in the diagnosis of hemangioma

Compression fracture • May be difficult to distinguish benign osteoporotic fracture from malign fracture • The posterior cortex and pedicles often spared • The marrow signal returns to normal in 1-3 months

Patient with RA Chronic benign compression fracture

Benign osteoporotic fracture

CT and xray a few weeks earlier show osteoporotic spine

Pathologic fracture with medulla compression

Spondylitis • Vertebral endplates affected • Hight T2 signal and often contrast enhancement i vertebral disc • May have adjacent soft tissue component

Discitis/spondylitis

T1 tse

T2tse

STIR

GdT1tse

T2 STIR sag

T1 sag

T1 sag Gd

Tbc-spondylitis with abscess in m psoas

Marrow infarction • May result from malignant infiltration • May be secondary to chemotherapy or steroid administration • Can be seen in patients with sickle-cell disease • Low T1, High STIR • Most in fatty yellow marrow

Non-neoplastic disorders

• • • •

Degenerative disease SAPHO Storage disorders ex Gaucher’s disease Seronegative spondylarthropati ex Bechterew

Irregular patchy marrow and degenerative disease

SAPHO • Synovitis, Acne, Pustulosis, Hyperostosis, Osteitis • Aseptic skeletal inflammatory process • Lesions in the anterior corner of the vertebras and also lesions affecting the endplates • Low T1, High T2

SAPHO

Gaucher’s disease



• • • •

Replacement of normal marrow cells by fibrotic tissue Autosomal recessive disease Begins in the spine Low signal on T1 and T2 Preservation of fat surrounding the basivertebral vein © Maas, Radiology

Mb Bechterew

© Hermann, RadioGraphics

Active lesions

Inactive lesions

Seronegative spondylarthropati

62 year old woman with one week history of pain at level Th6-Th8

Diagnostic punctions

Indications: - Investigation of obscure malignancy - Spondylitis - Obscure changes in skeleton and soft tissue in particular in the spine

Suspicion of infectious spondylitis

Suspicion of vertebral metastasis

Suspicion of metastasis in S1

Conclusion • Bone marrow is a functional tissue that changes through life • MRI is useful for differentiating between benign and malignant processes • MRI is capable of detecting bone marrow abnormalities in oncologic diseases as well as evaluate treatment response

Thank you for your attention!