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!