Jurnal Reading

Imaging in Bone Metastases

Joko Santoso1410029053

Fakultas KedokteranUniversitas Mulawarman

Samarinda2015

Overview

• Metastases to bone the most common malignant tumors involving bone.

• Imaging detection, diagnosis, prognostication, treatment planning, and follow up of bone metastases.

Overview

• Bone metastases multiple at time of diagnosis.

• In adult occur in the axial skeleton and other sites with residual red marrow.

• 90% site of bone metastases vertebra, pelvis, proximal part of femur, ribs, proximal part of humerus, and skull.

Overview

• Certain carcinoma may have a predilection skeletal sites.

• 50% bone metastases to hands and feet ca lung.

• Tumor from pelvis lumbosacral spine.

Pathophysiology

• Direct extension

• Retrograde venous flow metastased from intra abdominal cancer

• Seeding with tumor emboli via blood circulation

Patophysiology

• Metastatic lession grow in the medullarycavity surrending bone is remodeled by of either osteoblastic or osteoclastic proccessdepands on type and location original cancer

Differential Diagnosis

• Bone island• Eosinophilic granuloma of the skeleton• Bone lymphoma• Osteomalacia• Renal osteodystrophy• Chronic osteomyelitis• Paget disease• Pelvic insufficiency fractures• Stress fractures• Tuberous sclerosis• Secondary OA

Radiography

• Maybe osteolytic, sclerotic, or mixed predominantly osteolytic

• Arise in medulla destroying cortex

• Without periosteal reaction

• Soft tissue extention is relative uncommon

Radiography

• Specific appearance of bone metastases is useful in suggesting of underlying primary malignancy.

• Osteolytic lession carcinoma of breast, lung, renal, thyroid.

• Osteoblastic lession carcinoma of prostate, stomach, carcinoid, colon, breast (10%), bladder, melanoma, and sof tissue sarcoma.

Radiography

• In vertebrae, clue of metastases pediculardestruction, associated soft-tissue mass, and angular or irregular deformity of vertebral endplates

Radiography

• Response of therapy initial manifestation of healing in osteolytic metastases is a sclerotic rim of reactive bone.

• Response therapy of mixed lessionmanifestation of healing is uniform lesionalsclerosis.

• For sclerosis lession difficult to assess compare to previous radiograph manifestation of healing is shrink or complately disappear.

Degree of Confident

• Relative insensitive only ≥ 2 cm lession are radiographically apparent.

• Apparent in radiograph after loss of 50% bone mineral content.

False Positives/Negatives

• On radiograph, destructive lesions of the trabecular bone may not be visible particularly in absence of reactive new bone or cortical envolement especially in elder.

• Osteolytic lesion can mimic OA, amyloidosis, cystic angiomatosis, infiltrative bone marrow lesions.

• Osteoblastic lesion can mimic bone island, tuberous sclerosis, mastocytosis, osteopoikilosis.

Computed Tomography

• Useful in further assessment of radiographically negative areas in patients who are symptomatic and in whom metastases are sugested clinically.

Degree of Confidence

• CT scanning is vastly superior to radiography in detection of trabecular and cortical bone destruction, soft tissue extension, and involvement of neurovascular structures.

• Usefulness on detecting early deposits in bone marrow is limited.

Magnetic Resonance Imaging

• MRI is more sensitive than 99Tc bone scitiscanning in detection of bone metastases.

• Metastatic seeding in bone marrow is characterized by long T1 relaxation times, whereas T2 relaxation times are variable, depending on tumor morphology.

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• Lesions are seen as focal or difuse areas of hypointensity on T1-weighted images and as areas of intermediate or high signal intensity on T2-weigted images

• The Bull’s eye or halo sign useful in distinguishing metastatic with benign lesions.

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• In vertebrae, additional criteria for malignancy include bulging of the posterior margin of the vertebral body, signal intensity changes that intense into the pedicle, and paraosseustumor spread.

Degree of Confidence

• MRI depicts early hematogenousdissemination of the tumor to the bone marrow before reaction in adjacent bone are detectable on 99mTc Scintiscan.

• Flickinger and Sanal reported sensitivities of 100% for MRI and 62% for scintiscanning and specificities of 62% for MRI and 100% for scintiscanning.

Nuclear Imaging

• 99mTc bone scintigraphy is an effective method for screening the whole body for bone metastases.

• Detecting metastatic bone deposits by the increased osteoblastic activity they induce.

Indications for bone scintiscanning

• Staging in asymptomatic patients.

• Evaluating persistent pain in the presence of equivocal or negative radiographic findings.

• Determining the extent of bone metastases in patients with positive radiograph finding.

• Differentiating metastatic from trauma fractures.

• Determining the therapeutic response to metastases.

• PET scan can identifying bone metastases at an early stage of growth, before host reaction to the osteoblast occur.

• PET scan detecting early increased glucose metabolism in neoplastic cells.

• Isotop imaging methods depict bone metastatic lesions as areas of increased tracer uptake.

• The classical pattern appears as presence of multiple randomly distributed focal lesions througout the skeleton.

• Finding of a solitary scintigraphic abnormality or just a few lesions may present special problems in interpretation of findings.

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