Osteopetrosis

3. Osteopetrosis • Tc-99m sulfur colloid, i.v. • intense liver/spleen uptake, little or none in the bone marrow • Trabecular --> compact bone --> Diffuse inc bone density • Anemia w/extramedullary hematopoiesis • ddx: (adults) • myelofibrosis • sclerotic metastases • renal osteodystrophy • multiple myeloma • Paget’s

5. “Brain Death” • 20 mCi Tc-99m DTPA, i.v. • “No evidence of effective cerebral perfusion” (this study does not evaluate the brainstem effectively) • Good perfusion of external carotid arteries, facial structure = “Hot nose sign” • This test used to aid in the determination of brain death • Ddx: • NONE! • This is an Aunt Minnie!

7. Biliary Leak • 3.3 mCi Tc99m mebrofenin, i.v. • leakage of tracer in the gallbladder fossa, subhepatic space, and pericolic gutter • treatment: place stent crossing the area of leak • ddx: • NONE! • This is an Aunt Minnie!

10. Renal Duplication • 1.1 mCi Tc-99m MAG3, i.v. • delayed uptake and no excretion in the right upper pole and filling defect in the bladder • dilated upper pole and ectopic ureterocele by US • Weigert-Meyer Rule • upper pole obstructs, ureter inserts medially and caudally • lower pole refluxes, inserts normally

13. Osteoblastoma • 4.4 mCi Tc-99m MDP, i.v. • focal intense activity in the proximal humeral metaphysis • eccentric oval lytic lesion with periosteal reaction • also occurs in the posterior elements of the spine and long bones • histologically similar to osteoid osteoma • ddx: • giant cell tumor • ABC • non-ossifying fibroma • osteosarcoma

15. Testicular Torsion • 15.2 mCi Tc-99m pertechnetate, i.v. • increased flow surrounding testicle but no flow within • bull’s eye appearance • valuable in children • epididymitis has increased flow and activity • ddx: • abscess • hematoma

17. Pulmonary gallium uptakedue to ChemoRx • Ga-67 citrate, 5-10 mCi, i.v. • Diffuse pulmonary uptake, normal bone, lacrimal glands, liver, and spleen uptake • correlate with normal CXR • ddx: • pneumonia (PCP in AIDS) • lymphoma • vasculitis

20. Tuberculosis & AIDS • Ga-67 citrate 5-10 mCi, i.v. • images obtained at 72 hrs • diffuse lymph node activity in the chest & abd • intense splenic activity • gallium binds transferrin (liver) and lactoferrin (salivary and lacrimal glands, nasopharynx, spleen, and bone marrow) • ddx: • lymphoma • sarcoid • infection (abscesses)

22. Focal Nodular Hyperplasia • 5.2 mCi Tc-99m SC • focally increased uptake in the medial segment of the left hepatic lobe • activity washes out • activity related to hepatic perfusion and distribution of normal Kupffer cells • most lesions are “cold” (mets, HCC, hemangioma, adenoma) • ddx: • NONE! • This is an Aunt Minnie!

24. Meckel’s diverticulum • 2.2 mCi Tc-99m pertecnetate, i.v. • abnormal focus of activity in the anterior right lower quadrant appears at the same time as normal gastric activity • ddx: • active GI bleeding from non-Meckel’s source • ectopic gastric mucosa in jejunal tic (adults) • duplication cyst • inflammation around intussusception (false +)

26. Horeshoe kidney • Findings: • Bone scan demonstrates abnormal location and configuration of kidneys • ddx: • NONE! • This is an Aunt Minnie!

29. Acute cholecystitis • Findings: • Normal hepatic uptake • Prompt visualization of CBD and small bowel • Non-visualization of GB despite morphine administration • “Rim sign” along inferior right lobe • ddx: • NONE! • This is an Aunt Minnie!

31. Graves dz • Findings: • Enlarged thyroid • Intense diffuse uptake • sx: hyperthyroid • ddx: • NONE! • This is an Aunt Minnie!

33. Parathyroid adenoma • Findings: • 99mTc MIBI scan • Intense focal uptake overlying left upper lobe • Persisent after thyroid washout • sx: hypercalemia • ddx: • NONE! • This is an Aunt Minnie!

35. Low probability for acute PE • Findings: • Perfusion defect in the posterior left lung • Linear activity along the lung periphery beyond perfusion defect = “stripe sign” • ddx: • NONE! • This is an Aunt Minnie!

37. Fibrous dysplasia • Findings: • Intense activity involving a single enlarged rib • ddx: • Focal trauma • Primary malignancy • Metastasis

39. Metastatic Ewing’s sarcoma • Findings: • Intense radiotracer activity in the humeral diaphysis • MR shows an aggressive lesion with cortical disruption and soft tissue edema • ddx: • Lymphoma • Osteosarcoma • Metastasis • osteomyelitis

41. Hypertrophic osteoarthropathy • Findings: • Diffuse increased linear activity along the long bones • ddx: • Pulmonary disease • Pachydermoperiostosis • Vascular insufficiency • Thyroid acropachy • Fluorosis

43. Sickle cell anemia • Findings: • Bone scan shows increased activity in the kidneys, a small spleen, and knees • ddx: • NONE! • This is an Aunt Minnie!

45. Tumoral calcinosis • Findings: • Intense mass-like uptake about the proximal lateral thigh • Plain film shows soft tissue calcification • ddx: • Myositis ossificans • Heterotopic ossification • Parosteal osteosarcoma

47. Absent thyroid activity • Findings: • No thyroid activity seen on a 99m-Tc study • ddx: • Hyperthyroid • painful: • subacute thyroiditis • painless: • exogenous thyroid • Hypothyroid • painless: • Hashimotos's • ablated thyroid • Recent I+ study • Congenital absence (v. rare)

50. Bilateral pars fractures • Findings: • Planar images of the spine demonstrate subtle increased activity at L5 • Coronal and axial SPECT images are diagnostic • ddx: • NONE! • This is an Aunt Minnie!