SKELETAL RADIONUCLIDE IMAGING III

1
SKELETAL RADIONUCLIDE IMAGING III

• Dr. Hussein Farghaly
• Nuclear Medicine Consultant
• PSMMC

2
CONTENTS

• Bone and BM physiology anatomy
• Bone scan
• Radiopharmaceutical,
• preparation,
• uptake and pharmacokinetics
• dosimetry,
• protocols,
• normal and altered distribution
• Clinical indication and Skeletal pathology
• Bone Marrow scan

3
Soft-tissue uptake in radionuclide
musculoskeletal imaging
HOME WORK
4
(No Transcript)
5
CLINICAL USES OF SKELETAL SCINTIGRAPHY
6
Metastatic Disease
The evaluation of osseous metastatic disease is
the most common use of skeletal scintigraphy.
7
Metastatic Disease, cont.
Patients may present with bone pain (5080) and
elevated alkaline phosphatase (77) but these
findings are nonspecific. Bone scan may be used
for staging, restaging, and monitoring therapy
effectiveness. T The decision on which patients
will need a bone scan depends on factors such as
the type and stage of tumor, history of pain, and
radiographic abnormalities. Over 90 of osseous
metastasis distribute to the red marrow. In
adults red marrow is found in the axial skeleton
and the proximal portions of the humeri and
femurs.
8
Metastatic Disease, cont.
As the tumor enlarges, the cortex becomes
involved. The body responds by attempts at
repair. The Tc-99m MDP binds to these regions
in areas of bone deposition. Therefore, scans
image the bone response to the tumor and not the
tumor itself. Even a 5 bone turnover can be
detected by bone scan. Radiographs, on the other
hand, require a minimum mineral loss of a 50
before a lesion is visualized. MRI is more
sensitive than bone scan because signal changes
in the marrow from the tumor can be visualized
directly. However whole body MRI is not widely
available and generally not practical at this
time.
9
Metastatic Disease, cont.
10
Metastatic Disease in Specific Tumors

• Prostate Carcinoma
• Until the introduction of the prostate specific
  antigen (PSA) blood test, bone scan was
  considered the most sensitive technique for
  detecting osseous metastasis.
• Serum alkaline phosphates measurement detects
  only half the cases detected by scintigraphy.
• Radiographs may be normal 30 of the time.
• The likelihood of an abnormal scintigram
  correlates with the clinical stage, Gleason
  score, and PSA level.
• Incidence of bone metastasis
• less than 5 early stage I
  disease,
• 10 in stage II
• 20 in stage III
• In patients with PSA levels less than 10 ng/ml,
  bone metastases are rarely found (lt1 of the
  time). Skeletal scintigrams are still indicated
  for symptomatic patients and for evaluation of
  suspicious areas seen radiographically.
• With increasing PSA levels, the chance of
  detecting metastatic disease increases.

11

• Breast Carcinoma
• Mean survival is only 24 months among those with
  confirmed bone disease.
• Like prostate cancer, stage of disease
  correlates with the incidence of osseous
• metastases on bone scan
• 0.5 in stage I,
• 23 in stage II,
• 8 in stage III,
• and 13 in stage
  IV.
• Bone scans are not generally performed in
  patients with stage I or II disease.
• Although skeletal scintigraphy has a high
  sensitivity for breast carcinoma, it may not
  detect all lesions, such as those contained in
  the marrow or more lytic lesions.

12

• Lung Carcinoma
• There is no complete agreement on when to use
  skeletal scintigraphy.
• Staging is generally done with CT, surgery
  (including mediastinoscopy and video-assisted
  thoracoscopic surgery
• VATS), and increasingly with F-18 FDG PET.
• Skeletal scintigraphy is useful in a patient who
  develops pain during or after treatment and
  helpful in planning radiation therapy.
• However, it appears less useful in cases of local
  and mediastinal invasion or with advanced disease
  where therapy will be palliative.

13
(No Transcript)
14

• Solitary Lesions
• The chance that a solitary lesion is due to
  malignancy varies by location .
• Focal rib uptake is likely due to fracture,
  whereas uptake
• extending along the rib is likely tumor.
• Common benign causes for a solitary focus of
  uptake
• arthritis and trauma.
• benign bone lesions (enchondroma, osteoma,
  fibrous dysplasia)
• osteomyelitis,
• monostotic Pagets

15

• Multiple focal lesions
• Is the classic pattern of metastatic disease in
  the skeleton
• Although this typical pattern provides a high
  degree of clinical certainty as to the diagnosis,
  several other etiologies can also have multiple
  areas of uptake

These must be differentiated from osseous
metastasis
16
Differential Diagnosis of Multiple Focal Lesions
The key is to recognize the different features
and patterns of these other etiologies. Final
diagnosis may depend on correlation with
anatomical imaging. Osteoarthritic changes
Location medial compartment of the knee,
hand, and wrist (especially at the base of the
first metacarpal), shoulder and bones of the
feet. Bilateral and on both sides of
the joint. Patella The patella
frequently shows increased uptake due to
chondromalacia and degenerative change.
Spine degenerative changes are more
problematic because both metastasis and arthritic
changes occur in the same location. SPECT may
localize a lesion to the pedicle that is the
typical location of metastasis. A bone scan
lesion in the central vertebral body and disc
space, could be degenerative or malignant and may
require short term follow up, CT or even MRI.
17
Differential Diagnosis of Multiple Focal Lesions
cont.

• TRUMA
• The findings of trauma can mimic the appearance
  of metastasis. Patients should be closely
  questioned for any history of trauma.
• In the ribs, a vertical alignment of focal
  abnormal uptake in several or successive ribs is
  classic for trauma.
• The nonrandom pattern is not expected in
  metastatic disease.
• A metastatic lesion tracks along the bone rather
  than remaining focal.
• Radiographic correlation may show the cortical
  disruption or callous formation. Because bone
  scan frequently detects fractures not seen on
  radiographs, correlation with CT or short-term
  follow-up bone scan may be needed if no fracture
  is seen on the radiograph. Persistently positive
  skeletal activity from old trauma poses another
  interpretive problem.

Typical appearance of rib fractures. A, Posterior
views of the chest reveal focal uptake in a
vertical alignment in the right lower ribs and a
recent left nephrectomy with resection of some
lower left ribs. B, A follow-up study 18 months
later shows resolution of the right rib uptake as
the fractures healed.
18
Differential Diagnosis of Multiple Focal Lesions
cont.

• A number of other etiologies can cause multifocal
  abnormalities
• -Infarctions in sickle cell anemia can
  cause multiple areas of increased and decreased
  uptake.
• - Cushings disease and osteomalacia, for
  example, frequently cause disproportionate rib
  lesions as compared with other areas.
• - Osteoporosis may result in dorsal
  kyphosis and classic fractures such as the
  vertebral insufficiency fractures and the H-type
  fracture of the sacrum.
• - Pagets disease may be differentiated
  from metastasis by an expansion of the bone and
  classic locations.

19
Flare Phenomenon

• Another potentially perplexing pattern is seen in
  some bone scans done on patients undergoing
  cyclical chemotherapy.
• When a patient has a good response to
  chemotherapy, the bone scan may paradoxically
  worsen, with a flare of increased activity.
• To add to the confusion, these patients may
  experience increased pain. If these lesions are
  followed radiographically, increased sclerosis is
  seen over 26 months because this is an
  osteoblastic response as the bone begins to heal.
• This is the same time frame that the bone scan
  typically shows increased uptake. The flare
  phenomenon reinforces the fact that tracer uptake
  is not in the tumor but rather in the surrounding
  bone.

20
Superscan

• A superscan is intense symmetric activity in the
  bones with diminished renal and soft tissue
  activity on a Tc99m diphosphonate bone scan
• This appearance can result from a range of
  aetiological factors
• diffuse metastatic disease
• prostatic carcinoma
• breast cancer
• transitional cell carcinoma (TCC)
• multiple myeloma (some difference in opinion)
• lymphoma
• patchy uptake nonetheless look at skull and
  ribs
• tends to somewhat spare the distal skeleton
• metabolic bone diseases
• renal osteodystrophy
• hyperparathyroidism 1 (often secondary
  hyperparathyroidism)
• osteomalacia
• will involve distal skeleton
• smoother uptake
• myelofibrosis / myelosclerosis
  mastocytosis wide spread Paget's
  disease

21
Metastatic superscan
22
Renal osteodystrophy. AB,The absence of soft
tissue uptake is striking with an appearance
similar to the superscanseen in metastatic
disease. The prominent rib end activity may help
differentiate the two etiologies. The native
kidneys had failed,and a renal transplant is
noted in the right iliac fossa. C, Increased
activity in the skull and sternum may be
especially prominent. Note the increased axial
skeletal uptake and paucity of soft tissue
background activity.
23
Superimposed appearances of metastatic and
metabolic superscan
24
Differentiation between metastatic and metabolic
superscan
HOME WORK