Imaging & Oncology

Question 1

Bone Lesion Imaging Indication

Answer 1

Xray is the most valuable initial imaging technique

• Benign: well-defined, no cortical destruction or periosteal reaction
• Malignant: Ill-defined, destructive, infiltrative marrow lesions

CT best for evaluating subtle bone changes

MRI better for soft-tissue & infiltrative marrow lesions

PET scans show metabolic activity and look for mets

Question 2

Pancoast’s Tumor

Answer 2

Extension of tumor @ apex of lung involving C8, T1, T2, nerves and possible destruction of ribs

-presents w/ shoulder pain radiating to the ulna

Question 3

3D CT Reconstruction Indications

Answer 3

When planning local resection

Excellent to evaluate bony architecture

Evaluate bone integrity, alignment, & stability

Preoperative planning for sites of fixation & reconstruction

Question 4

Bone Scan Bright and Dark spots

Answer 4

Bright spots are either arthritis or metastases

Liver scan: dark spots are metastases

-Metastatic disease increases risk of pathologic fracture

Question 5

PET Scan Contrast

Answer 5

Fludeoxyglucose (FDG)

-Collects in highly metastatic tissue

Higher grade malignancies detected more than benign processes

-Low-grade cartilage lesions underestimated

Question 6

MRI - T1 & T2 and contrast agents

Answer 6

T1: Dark = water, edema, tumor, hemorrhage

Bright = fat, subacute hemorrhage, melanin, cerebral infarct necrosis

T2: Dark = low protein density, fibrous tissue, protein-rich fluid

Bright = increased water/edema, tumor, infarct, subacute hemorrhage

Contrast agent: gadolinium - increases structure visibility

Question 7

Xray Pros and Cons

Answer 7

Simple, inexpensive, readily available, easily interpreted

Radiation, poor tissue contrast, technician dependent, 2D

Question 8

CT Scan Pros and Cons

Answer 8

Rapid, 3D capability, axial imaging, good bone detail

Highest radiation, motion & metal artifact, limited ST contrast

Question 9

Bone Scan Pros and Cons

Answer 9

Images metabolic activity, very sensitive in bones, low cost

Non-specific, poor detail, anatomic changes not visualized

Question 10

MRI Pros and Cons

Answer 10

Superior tissue resolution

Expensive, motion & metal artifact, can’t use in some patients

Question 11

Ultrasound Pros and Cons

Answer 11

Very safe, inexpensive, quick

Small field of view, technician and radiologist dependent, artifacts