DOI:10.2214/AJR.06.1215
AJR 2007; 188:W467-W474
© American Roentgen Ray Society
Characterization of Focal Bone Lesions in the Axial Skeleton: Performance of Planar Bone Scintigraphy Compared with SPECT and SPECT Fused with CT
Klaus Strobel1,
Cyrill Burger1,
Burkhardt Seifert2,
Daniela B. Husarik1,
Jan D. Soyka1 and
Thomas F. Hany1
1 Department of Nuclear Medicine, University Hospital Zurich, Rämistrasse
100, Zurich, Switzerland, 8091.
2 Institute of Biostatistics, University Hospital Zurich, Zurich,
Switzerland.
Received September 13, 2006;
accepted after revision November 21, 2006.
Address correspondence to K. Strobel
(klaus.strobel{at}usz.ch).
WEB This is a Web exclusive article.
Abstract
OBJECTIVE. The purpose of this study was to evaluate the diagnostic
performance of planar 99mTc methylene diphosphonate bone
scintigraphy compared with SPECT and SPECT fused with CT in patients with
focal bone lesions of the axial skeleton.
SUBJECTS AND METHODS. Thirty-seven patients with 42 focal lesions of
the axial skeleton were included in this prospective study. All patients
underwent planar scintigraphy, SPECT through the focal lesions, and
SPECT-guided CT. SPECT and CT images then were fused digitally. The three
types of images were evaluated separately from one another by two experienced
reviewers working to consensus. Visibility of the lesions, diagnostic
performance, and certainty in diagnosis were evaluated. Performance for
specific diagnoses also was evaluated. Histologic, MRI, and clinical follow-up
findings were used as the reference standard.
RESULTS. Visibility of the lesions was significantly better with
SPECT than with planar scintigraphy (p < 0.0001). Sensitivity and
specificity for differentiation of benign and malignant bone lesions were 82%
and 94% for planar scintigraphy, 91% and 94% for SPECT, and 100% and 100% for
SPECT fused with CT. Differences between the three methods of differentiating
benign and malignant lesions did not reach statistical significance. Certainty
in diagnosis was significantly higher for SPECT fused with CT than for planar
scintigraphy (p = 0.004) and SPECT (p = 0.004). A specific
diagnosis was made with planar scintigraphy in 64% of cases, with SPECT in
86%, and with SPECT fused with CT in all cases.
CONCLUSION. Planar scintigraphy may suffice for differentiating
benign and malignant lesions of the axial skeleton, but SPECT fused with CT
significantly increases certainty in diagnosis and is the best tool for making
a specific diagnosis.
Keywords: bone • CT • musculoskeletal imaging • oncologic imaging • SPECT
Introduction
Bone scintigraphy is still the work-horse of nuclear medicine in the
search for bone metastasis in patients with malignant tumors, especially
prostate and breast cancer. Bone scintigraphy is widely available, relatively
inexpensive, and highly sensitive in the detection of bone metastasis. The
high sensitivity correlates with a lower specificity because many benign
conditions, such as degenerative joint disease, infections, and benign bone
tumors, exhibit increased uptake of radiotracer
[1].
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Fig. 1A —56-year-old woman who underwent staging 1 week after resection of
multicentric breast cancer and axillary lymph node metastasis. Anterior
(A) and posterior (B) planar bone scintigraphic images with
increased focal uptake (arrow, A) in right side of sternum.
Differentiation between degenerative uptake in right sternoclavicular joint
and solitary metastatic lesion in sternum is difficult.
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Fig. 1B —56-year-old woman who underwent staging 1 week after resection of
multicentric breast cancer and axillary lymph node metastasis. Anterior
(A) and posterior (B) planar bone scintigraphic images with
increased focal uptake (arrow, A) in right side of sternum.
Differentiation between degenerative uptake in right sternoclavicular joint
and solitary metastatic lesion in sternum is difficult.
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Fig. 1C —56-year-old woman who underwent staging 1 week after resection of
multicentric breast cancer and axillary lymph node metastasis. Axial
(C-E) and coronal (F-H) CT (C, F), SPECT (D, G),
and software-fused SPECT/CT (E, H) images at level of focal uptake.
Fused image shows focal uptake is in sternum (arrow, E and
H) and not in sternoclavicular joint. MRI findings (not shown)
confirmed SPECT fused with CT diagnosis of solitary metastatic lesion of
breast cancer.
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Fig. 1D —56-year-old woman who underwent staging 1 week after resection of
multicentric breast cancer and axillary lymph node metastasis. Axial
(C-E) and coronal (F-H) CT (C, F), SPECT (D, G),
and software-fused SPECT/CT (E, H) images at level of focal uptake.
Fused image shows focal uptake is in sternum (arrow, E and
H) and not in sternoclavicular joint. MRI findings (not shown)
confirmed SPECT fused with CT diagnosis of solitary metastatic lesion of
breast cancer.
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Fig. 1E —56-year-old woman who underwent staging 1 week after resection of
multicentric breast cancer and axillary lymph node metastasis. Axial
(C-E) and coronal (F-H) CT (C, F), SPECT (D, G),
and software-fused SPECT/CT (E, H) images at level of focal uptake.
Fused image shows focal uptake is in sternum (arrow, E and
H) and not in sternoclavicular joint. MRI findings (not shown)
confirmed SPECT fused with CT diagnosis of solitary metastatic lesion of
breast cancer.
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Fig. 1F —56-year-old woman who underwent staging 1 week after resection of
multicentric breast cancer and axillary lymph node metastasis. Axial
(C-E) and coronal (F-H) CT (C, F), SPECT (D, G),
and software-fused SPECT/CT (E, H) images at level of focal uptake.
Fused image shows focal uptake is in sternum (arrow, E and
H) and not in sternoclavicular joint. MRI findings (not shown)
confirmed SPECT fused with CT diagnosis of solitary metastatic lesion of
breast cancer.
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Fig. 1G —56-year-old woman who underwent staging 1 week after resection of
multicentric breast cancer and axillary lymph node metastasis. Axial
(C-E) and coronal (F-H) CT (C, F), SPECT (D, G),
and software-fused SPECT/CT (E, H) images at level of focal uptake.
Fused image shows focal uptake is in sternum (arrow, E and
H) and not in sternoclavicular joint. MRI findings (not shown)
confirmed SPECT fused with CT diagnosis of solitary metastatic lesion of
breast cancer.
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Fig. 1H —56-year-old woman who underwent staging 1 week after resection of
multicentric breast cancer and axillary lymph node metastasis. Axial
(C-E) and coronal (F-H) CT (C, F), SPECT (D, G),
and software-fused SPECT/CT (E, H) images at level of focal uptake.
Fused image shows focal uptake is in sternum (arrow, E and
H) and not in sternoclavicular joint. MRI findings (not shown)
confirmed SPECT fused with CT diagnosis of solitary metastatic lesion of
breast cancer.
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The combination of functional and morphologic findings with PET/CT
increases the diagnostic performance of PET alone
[2-4].
Similarly, SPECT/CT promises to overcome the insufficient specificity of
planar scintigraphy and SPECT alone
[5-7].
SPECT improves lesion to background contrast enhancement and allows detailed
anatomic localization. SPECT thus promises to be useful in imaging of complex
anatomic regions such as the spine. Fused SPECT/CT images can be obtained with
integrated SPECT/CT scanners, in which CT data are used for attenuation
correction, and with software fusion of SPECT and CT data obtained with two
separate scanners [5,
6]. MDCT rapidly provides
detailed morphologic information about osseous structures. The aim of this
study was to evaluate the diagnostic performance of planar 99mTc
methylene diphosphonate bone scintigraphy compared with SPECT and fused SPECT
and 64-MDCT data obtained with separate systems in patients with focal lesions
of the axial skeleton..
Subjects and Methods
Patients
Between August 2005 and December 2005, a total of 37 consecutively enrolled
patients (20 women, 17 men; mean age, 64.4 years; age range, 34-83 years) with
foci of abnormal radiotracer uptake in the axial skeleton on planar bone
scintigraphy were included in this prospective study. Written informed consent
in accordance with the regulations of the institutional review board had been
given by all patients before CT data acquisition. Forty-two focal lesions of
the axial skeleton in the following locations were evaluated: spine
(n = 30), sternum (n =1), rib (n = 2), sacrum
(n = 7), acetabulum (n = 1), and mandible (n =1).
Thirty patients had underlying malignant disease (Fig.
1A,
1B,
1C,
1D,
1E,
1F,
1G,
1H) (16, breast cancer; nine,
prostate cancer; two, otolaryngologic cancer; one, esophageal cancer; one,
lymphoma; one, renal cell cancer), and seven patients had skeletal pain (Figs.
2A,
2B,
2C,
2D,
2E,
2F,
2G,
2H and
3A,
3B,
3C,
3D,
3E).
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Fig. 2C —34-year-old man with skeletal pain. Axial (C-E) and coronal
(F-H) CT (C, F), SPECT (D, G), and fused SPECT/CT (E,
H) images at level of focal uptake show increased uptake belongs to
polylobulated sclerotic lesion (arrowheads, C and F) in
left part of vertebral body. Fused images show lesion (arrows,
E and H) with good match between CT lesion and focal uptake on
SPECT image. Diagnosis of melorheostosis was established. MRI and follow-up CT
findings 6 months after CT and SPECT confirmed diagnosis.
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Fig. 2D —34-year-old man with skeletal pain. Axial (C-E) and coronal
(F-H) CT (C, F), SPECT (D, G), and fused SPECT/CT (E,
H) images at level of focal uptake show increased uptake belongs to
polylobulated sclerotic lesion (arrowheads, C and F) in
left part of vertebral body. Fused images show lesion (arrows,
E and H) with good match between CT lesion and focal uptake on
SPECT image. Diagnosis of melorheostosis was established. MRI and follow-up CT
findings 6 months after CT and SPECT confirmed diagnosis.
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Fig. 2E —34-year-old man with skeletal pain. Axial (C-E) and coronal
(F-H) CT (C, F), SPECT (D, G), and fused SPECT/CT (E,
H) images at level of focal uptake show increased uptake belongs to
polylobulated sclerotic lesion (arrowheads, C and F) in
left part of vertebral body. Fused images show lesion (arrows,
E and H) with good match between CT lesion and focal uptake on
SPECT image. Diagnosis of melorheostosis was established. MRI and follow-up CT
findings 6 months after CT and SPECT confirmed diagnosis.
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Fig. 2F —34-year-old man with skeletal pain. Axial (C-E) and coronal
(F-H) CT (C, F), SPECT (D, G), and fused SPECT/CT (E,
H) images at level of focal uptake show increased uptake belongs to
polylobulated sclerotic lesion (arrowheads, C and F) in
left part of vertebral body. Fused images show lesion (arrows,
E and H) with good match between CT lesion and focal uptake on
SPECT image. Diagnosis of melorheostosis was established. MRI and follow-up CT
findings 6 months after CT and SPECT confirmed diagnosis.
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Fig. 2G —34-year-old man with skeletal pain. Axial (C-E) and coronal
(F-H) CT (C, F), SPECT (D, G), and fused SPECT/CT (E,
H) images at level of focal uptake show increased uptake belongs to
polylobulated sclerotic lesion (arrowheads, C and F) in
left part of vertebral body. Fused images show lesion (arrows,
E and H) with good match between CT lesion and focal uptake on
SPECT image. Diagnosis of melorheostosis was established. MRI and follow-up CT
findings 6 months after CT and SPECT confirmed diagnosis.
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Fig. 2H —34-year-old man with skeletal pain. Axial (C-E) and coronal
(F-H) CT (C, F), SPECT (D, G), and fused SPECT/CT (E,
H) images at level of focal uptake show increased uptake belongs to
polylobulated sclerotic lesion (arrowheads, C and F) in
left part of vertebral body. Fused images show lesion (arrows,
E and H) with good match between CT lesion and focal uptake on
SPECT image. Diagnosis of melorheostosis was established. MRI and follow-up CT
findings 6 months after CT and SPECT confirmed diagnosis.
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Fig. 3C —55-year-old man with skeletal pain. Axial CT (C), SPECT
(D), and fused SPECT/CT (E) images show focal uptake corresponds
to periosteal reaction (arrow, C and E) caused by old
rib fracture.
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Fig. 3D —55-year-old man with skeletal pain. Axial CT (C), SPECT
(D), and fused SPECT/CT (E) images show focal uptake corresponds
to periosteal reaction (arrow, C and E) caused by old
rib fracture.
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Fig. 3E —55-year-old man with skeletal pain. Axial CT (C), SPECT
(D), and fused SPECT/CT (E) images show focal uptake corresponds
to periosteal reaction (arrow, C and E) caused by old
rib fracture.
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Planar Bone Scintigraphy
All patients underwent whole-body bone planar scintigraphy in the anterior
and posterior positions 3 hours after injection of 450 MBq of 99mTc
methylene diphosphate. Scintigraphy was performed with a dual-head system
(Millenium VG, GE Healthcare) equipped with a low-energy high-resolution
parallel-hole collimator.
SPECT
After completion of planar scintigraphy, all patients underwent SPECT with
the gamma camera used for scintigraphy. The detectors were positioned on the
focal lesions localized with planar scintigraphy. SPECT data were collected in
step-and-shoot mode with an angular range of 180° in 3° increments and
a duration of 30 seconds each. Projection data were collected with a zoom
factor of 1 and a 128 x 128 matrix size. SPECT images were iteratively
reconstructed with an ordered subset expectation maximization algorithm
implemented on a clinical workstation (Xeleris 1.221, GE Healthcare). The
final pixel size was 4.42 mm in all directions.
CT
After SPECT data collection, patients were transferred to a standalone
64-MDCT scanner (Lightspeed VCT, GE Healthcare). Care was taken to reproduce
exactly the same patient position as for the SPECT acquisition. Unenhanced CT
was performed in helical mode with a table speed of 10.6 mm/rotation and a
rotation time of 0.6 second. The other scan parameters depended slightly on
the clinical situation. A voltage of 120 or 140 kV was used, and the current
was automatically adjusted in the range of 100-700 mA, depending on the
setting of a noise index ranging from 24 to 33. No IV contrast material was
injected. CT images were reconstructed with the standard parameters and
reviewed in the bone window. To improve contrast enhancement, CT images were
reformatted as maximum intensity projection images in the sagittal and coronal
planes with an in-plane pixel size of 0.7 mm and a slice thickness of 5
mm.
SPECT and CT Image Fusion
All images were transferred to a workstation running software for
quantitative analysis (PMOD v2.65, PMOD Technologies). We interactively
matched the SPECT images to the CT maximum intensity projection images by
bringing internal anatomic landmarks (e.g., iliac crest) into agreement. To
confirm the matching quality, we inspected fusion images in all directions
(transverse, coronal, sagittal).
Image Interpretation
Planar scintigraphy, SPECT, and fused SPECT and CT images were evaluated by
two experienced reviewers in consensus. One reviewer was double board
certified in nuclear medicine and radiology, and the other was board certified
in radiology with special training in musculoskeletal radiology and had 3
years of experience in nuclear medicine. The reviewers were blinded to
clinical information and medical history. The three types of images were
evaluated separately: first the planar bone scintigraphic images, then the
SPECT images, and last the fused SPECT and CT images. Visibility of the focal
lesions was graded on the following five-point scale: 0, not visible; 1, poor
visibility; 2, moderate visibility; 3, good visibility; 4, very good
visibility. Diagnostic performance in differentiation of benign and malignant
focal bone lesions was reported as sensitivity, specificity, accuracy, and
negative and positive predictive values. Certainty in diagnosis was graded on
the following three-point scale: 0, undecided; 1, probably correct; 2, most
likely correct.
Performance in specific diagnosis of a lesion as benign (e.g., fracture,
facet joint osteoarthritis, spondylosis deformans) or malignant also was
evaluated. For planar scintigraphy and SPECT, the criteria for classifying a
focal bone lesion as malignant were that, first, focal radiotracer uptake
greater than in the anterior iliac spine located in a anatomic location
typical of a metastasis (pedicle, vertebral body) was considered to indicate
malignancy. Second, radiotracer uptake equal to or lower than uptake in the
anterior iliac spine and uptake that involved both sides of a joint (facet
joint, vertebral body endplates) were considered to indicate a lesion was
benign. The additional criteria for the CT part of the fused SPECT and CT
interpretation were that osteolytic lesions without sclerosis and osteoblastic
lesions were considered malignant and that sclerotic lesions with
spondylophytes and disk space narrowing or in the subchondral region of a
joint together with joint space narrowing, subchondral cysts, and osteophytes
were considered benign. Histologic (one patient), MRI (10 patients),
scintigraphic (four patients), CT (five patients), and clinical follow-up
findings for at least 12 months (all patients), including tumor markers such
as prostate-specific antigen in prostate cancer patients and CA 15-3 in breast
cancer patients, were used as the reference standard.
Statistical Analysis
Grades of visibility and certainty were recorded as percentages and mean
± SD. Sensitivity, specificity, accuracy, negative predictive value,
and positive predictive value for the diagnosis of malignant or benign focal
bone lesion were calculated for planar scintigraphy, SPECT, and fused SPECT
and CT. Sign tests were used to analyze differences in diagnostic performance
of the three imaging techniques. With Bonferroni correction, p <
0.016 was considered to indicate a significant difference. SPSS 11 software
(SPSS) was used for statistical analysis.
Results
Of 42 lesions, 11 were metastatic, 27 degenerative, two posttraumatic, and
two benign tumors (Table 1).
Visibility of the lesions was significantly better with SPECT than with planar
scintigraphy (mean value, 3.6 ± 0.6 vs 2.7 ± 0.6; p
< 0.0001). The sensitivity and specificity for differentiation of benign
and malignant bone lesions were 82% and 94% for planar scintigraphy, 91% and
94% for SPECT, and 100% and 100% for SPECT fused with CT. Differences between
the three methods for differentiation of benign and malignant lesions did not
reach statistical significance (Table
2).
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TABLE 1: Characteristics of 42 Lesions in the Axial Skeleton in 37 Patients and
Diagnoses with Different Techniques
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TABLE 2: Diagnostic Performance in Differentiation of Benign and Malignant Focal
Bone Lesions in the Axial Skeleton
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Certainty in diagnosis of a lesion as benign or malignant was significantly
higher with SPECT fused with CT (mean value, 1.9 ± 0.3) than with
planar scintigraphy (mean value, 1.0 ± 0.6; p = 0.004) and
SPECT (mean value, 1.2 ± 0.6; p = 0.004), but SPECT was not
superior to planar scintigraphy (p = 0.25)
(Table 3). A specific diagnosis
was made with an accuracy of 64% (27/42) with planar scintigraphy, 86% (36/42)
with SPECT, and 100% (42/42) with SPECT fused with CT. SPECT fused with CT and
SPECT were significantly superior to planar scintigraphy (p = 0.008
and p = 0.0001), but SPECT fused with CT was not significantly
superior to SPECT (p = 0.031) for specific diagnosis.
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TABLE 3: Certainty in Diagnosis for Differentiation of Benign and Malignant Focal
Bone Lesions in the Axial Skeleton
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Discussion
Focal lesions in the axial skeleton are significantly better displayed with
SPECT and with SPECT fused with CT than with planar bone scintigraphy. Planar
scintigraphy may suffice for differentiating benign and malignant lesions.
However, SPECT fused with CT significantly increases certainty in diagnosis
and is the best tool for making a specific diagnosis
[6,
8].
Detection of skeletal metastasis is clinically important because of
associated symptoms, complications such as pathologic fractures, and
significance for staging, treatment, and prognosis. However, differentiating
benign and metastatic bone lesions can be difficult with planar scintigraphy
alone. Because of summation of different structures, such as vertebral body,
pedicle, and facet and costovertebral joints and because of the high incidence
of degenerative changes in the spine, characterization of focal spinal lesions
with planar scintigraphy alone can be challenging. SPECT/CT with various
radiotracers has been used for indications such as imaging of infection;
neuroendocrine tumors; and diseases of the liver, thyroid, and parathyroid
glands [5,
9-15].
It has been found that detection and characterization of focal bone lesions
improve with SPECT
[16-19].
Imaging is moving toward a combination of techniques that yield functional and
anatomic information [20,
21]. With the increased
availability of integrated SPECT/CT scanners and improved performance of
postprocessing image-fusion software, it becomes more and more important to
define the indications for fused imaging.
In our study, visibility of the lesions was significantly better with SPECT
than with planar scintigraphy. Sedonja et al.
[22] performed planar
scintigraphy and SPECT on 37 patients with lower back pain without known
malignant lesions and on 38 patients with confirmed malignant disease.
Overall, significantly more metastatic lesions were detected with SPECT
(SPECT, 58 of 64 lesions; planar scintigraphy, 42 of 64 lesions; p
< 0.01). These investigators also measured lesion-to-background ratios for
malignant lesions of the spine and found a significantly higher ratio with
SPECT (2.26) than with planar scans (1.86). Furthermore, our results showed
that accuracy in definition of malignant lesions increased from planar
scintigraphy to SPECT and to SPECT fused with CT, but the difference in
diagnostic performance was not significant. Therefore, planar scintigraphy
seems to be sufficiently accurate for determining whether a patient has
osseous metastatic disease.
Utsunomiya et al. [6]
compared diagnostic confidence in side-by-side interpretation of CT and SPECT
data with confidence in interpretation of fused images of patients with
suspected bone metastasis and found that interpretation of fused images
increases confidence. This finding proves that the process of software fusion
is not simply an academic exercise. Similarly, our results showed that the
highest degree of confidence in diagnosis is obtained with fused images
compared with SPECT alone and with planar scintigraphy alone. With SPECT fused
with CT, 91% of diagnoses were made with the highest confidence level (SPECT,
29%; planar scintigraphy, 19%). Confidence in diagnosis is an important factor
not only for convincing referring physicians and defending a diagnosis in
interdisciplinary meetings but also for avoiding additional expensive imaging
such as MRI.
Findings on SPECT fused with CT led to a specific diagnosis in all
patients. Often patients with malignant tumors have unclear pain in the
skeleton. In these situations, it does not suffice to rule out metastasis. The
cause of benign focal uptake should be evaluated carefully because many
underlying diseases can influence treatment. Osteoid osteoma can be managed by
resection or radiofrequency ablation
[23]. In the case of
osteoporotic vertebral body, sacral, and rib fractures, bisphosphonate
treatment and vertebroplasty can be considered
[23]. Degenerative lesions, if
concordant with the symptoms, can be managed with percutaneous injections of
anesthetics or corticosteroids. It has been proven that findings on bone
scintigraphy are predictive of the short-term outcome of facet-joint
injections in patients with lower back pain. It may be possible to use SPECT
and, even better, SPECT/CT to differentiate costovertebral joint
osteoarthritis and facet joint osteoarthritis and to guide therapeutic
intervention
[24-26].
Our study showed that digital fusion of bone SPECT and full-dose CT images
is technically feasible. Correct anatomic fusion by bringing internal anatomic
landmarks into agreement was possible for all patients. The disadvantage of
this technique is that it is time consuming in the daily routine: It takes
approximately 15 minutes to fuse images. The advantage is that the images also
can be fused with CT data obtained at other institutions. There is no need to
repeat CT studies if images of the relevant region are available in DICOM
format. The clear advantage of an in-line SPECT/CT system is greater comfort
for the patient because transfer from one scanner to another is not necessary.
Obviation of transfer also results in faster imaging and postprocessing
workflow. Römer et al. [8]
recently reported data on cancer patients who underwent imaging with an inline
SPECT/CT system. The authors found that SPECT-guided CT clarified most of the
lesions. The 64-MDCT technique substantially improved noninvasive imaging of
the coronary arteries, as has been shown in several publications
[27].
To our knowledge, inline systems with a combination of SPECT and 64-MDCT
are not available. On the other hand, the quality of 4- to 6-MDCT, which is
available in combined scanners, seems sufficient for evaluation of bone
lesions in the axial skeleton. In combined scanners, the CT data can be used
for attenuation correction of the SPECT images. Attenuation correction with CT
data from separate scanners also is feasible, as has been found in heart
studies [28]. Most authorities
consider MRI of scintigraphically indeterminate lesions of the axial skeleton
the most appropriate examination. Compared with CT, MRI is more time consuming
and more expensive, and contraindications such as severe claustrophobia and
the presence of pacemaker implants have to be considered. Nevertheless,
SPECT-guided MRI of indeterminate spinal lesions should be the first choice
for imaging of young patients. Integrated SPECT/MRI scanners are not
available, but our experience with software-fused SPECT/MRI fusion has shown
that this approach is feasible for the axial skeleton.
Our study had limitations. Histologic confirmation was not available for
all patients because we could not ethically justify obtaining histologic proof
of the diagnosis of all lesions identified, especially the degenerative
lesions. Nevertheless, we did our best to establish the reference standard by
using histologic, additional MRI, and planar scintigraphic follow-up whenever
possible. In addition, clinical follow-up was used as the reference standard
in all cases.
In conclusion, the visibility of focal lesions in the axial skeleton is
significantly better with SPECT and with SPECT fused with CT than with planar
bone scintigraphy. Planar scintigraphy may suffice for differentiation of
benign and malignant lesions of the axial skeleton, but SPECT fused with CT
significantly increases the certainty of diagnosis and is the best tool for
specific diagnosis.
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Abstract
Introduction
