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European Journal of Nuclear Medicine 05/2013; · 4.53 Impact Factor
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ABSTRACT: There is evidence in some solid tumors that textural features of tumoral uptake in (18)F-FDG PET images are associated with response to chemoradiotherapy and survival. We have investigated whether a similar relationship exists in non-small cell lung cancer (NSCLC). METHODS: Fifty-three patients (mean age, 65.8 y; 31 men, 22 women) with NSCLC treated with chemoradiotherapy underwent pretreatment (18)F-FDG PET/CT scans. Response was assessed by CT Response Evaluation Criteria in Solid Tumors (RECIST) at 12 wk. Overall survival (OS), progression-free survival (PFS), and local PFS (LPFS) were recorded. Primary tumor texture was measured by the parameters coarseness, contrast, busyness, and complexity. The following parameters were also derived from the PET data: primary tumor standardized uptake values (SUVs) (mean SUV, maximum SUV, and peak SUV), metabolic tumor volume, and total lesion glycolysis. RESULTS: Compared with nonresponders, RECIST responders showed lower coarseness (mean, 0.012 vs. 0.027; P = 0.004) and higher contrast (mean, 0.11 vs. 0.044; P = 0.002) and busyness (mean, 0.76 vs. 0.37; P = 0.027). Neither complexity nor any of the SUV parameters predicted RECIST response. By Kaplan-Meier analysis, OS, PFS, and LPFS were lower in patients with high primary tumor coarseness (median, 21.1 mo vs. not reached, P = 0.003; 12.6 vs. 25.8 mo, P = 0.002; and 12.9 vs. 20.5 mo, P = 0.016, respectively). Tumor coarseness was an independent predictor of OS on multivariable analysis. Contrast and busyness did not show significant associations with OS (P = 0.075 and 0.059, respectively), but PFS and LPFS were longer in patients with high levels of each (for contrast: median of 20.5 vs. 12.6 mo, P = 0.015, and median not reached vs. 24 mo, P = 0.02; and for busyness: median of 20.5 vs. 12.6 mo, P = 0.01, and median not reached vs. 24 mo, P = 0.006). Neither complexity nor any of the SUV parameters showed significant associations with the survival parameters. CONCLUSION: In NSCLC, baseline (18)F-FDG PET scan uptake showing abnormal texture as measured by coarseness, contrast, and busyness is associated with nonresponse to chemoradiotherapy by RECIST and with poorer prognosis. Measurement of tumor metabolic heterogeneity with these parameters may provide indices that can be used to stratify patients in clinical trials for lung cancer chemoradiotherapy.
Journal of Nuclear Medicine 11/2012; · 6.38 Impact Factor
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ABSTRACT: (18)F-Fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) is now routinely used in oncological imaging for diagnosis and staging and increasingly to determine early response to treatment, often employing semiquantitative measures of lesion activity such as the standardized uptake value (SUV). However, the ability to predict the behaviour of a tumour in terms of future therapy response or prognosis using SUVs from a baseline scan prior to treatment is limited. It is recognized that medical images contain more useful information than may be perceived with the naked eye, leading to the field of "radiomics" whereby additional features can be extracted by computational postprocessing techniques. In recent years, evidence has slowly accumulated showing that parameters obtained by texture analysis of radiological images, reflecting the underlying spatial variation and heterogeneity of voxel intensities within a tumour, may yield additional predictive and prognostic information. It is hoped that measurement of these textural features may allow better tissue characterization as well as better stratification of treatment in clinical trials, or individualization of future cancer treatment in the clinic, than is possible with current imaging biomarkers. In this review we focus on the literature describing the emerging methods of texture analysis in (18)FDG PET/CT, as well as other imaging modalities, and how the measurement of spatial variation of voxel grey-scale intensity within an image may provide additional predictive and prognostic information, and postulate the underlying biological mechanisms.
European Journal of Nuclear Medicine 10/2012; · 4.53 Impact Factor
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ABSTRACT: The aim of this study was to evaluate the relationship between different quantification methods used for the measurement of bone plasma clearance (K(i)) using F-PET at the hip and lumbar spine.
Twelve healthy postmenopausal women aged 52-71 years were recruited. Each participant underwent 60-min dynamic F-PET scans at the lumbar spine and hip on two separate occasions with an injected activity of 90 and 180 MBq, respectively. Image-derived input functions were obtained at the aorta from the lumbar spine scans. K(i) was evaluated using a three-compartment four-parameter model (K(i-4k)), three-compartment three-parameter model (K(i-3k)), Patlak analysis (K(i-Pat)), spectral analysis (K(i-Spec)) and deconvolution (K(i-Decon)). Standardized uptake values (SUVs) were also measured.
The Pearson correlation between K(i-4k) and K(i-3k), K(i-Pat), K(i-Spec), K(i-Decon) and SUV were 0.91, 0.97, 0.94, 0.95 and 0.93, respectively, with a significance of P less than 0.0001. The differences between the correlations measured using Fisher's Z-test were not significant (P>0.05). Bland-Altman analysis showed that the limits of agreement for K(i) measured as the SD of the differences were 0.0082 (25.9%), 0.0062 (11.7%), 0.0098 (20.1%) and 0.0056 (25.5%) ml/min/ml, respectively, and the biases were -0.0081 (-23.8%), -0.0075 (-23.7%), -0.0107 (-29.5%) and -0.0015 (0.8%) ml/min/ml, respectively.
All five methods of quantification (K(i-3k), K(i-Pat), K(i-Spec), K(i-Decon) and SUV) strongly correlated with K(i-4k). Although systematic differences of up to 29% were found between K(i-4k) and the other methods (K(i-3k), K(i-Pat), K(i-Spec) and K(i-Decon)), these should not affect the conclusions of clinical studies, provided the methods are applied consistently. However, care should be taken when comparing reports that use different methods of quantification.
Nuclear Medicine Communications 03/2012; 33(6):597-606. · 1.40 Impact Factor
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ABSTRACT: The use of image-derived arterial input functions (IDAIF) for the dynamic quantification of bone metabolism using 18F-fluoride positron emission tomography 18F-PET is an attractive alternative to direct arterial blood sampling.
(a) To validate a method for obtaining the IDAIF by imaging the femoral artery against a method for deriving the IDAIF at the aorta that was previously validated against direct arterial sampling. (b) To compare the accuracy of bone plasma clearance measurements (Ki) at the total hip site obtained using the femoral artery IDAIF against Ki values at the same site obtained using the aorta IDAIF.
Twelve healthy postmenopausal women with a mean age of 62.6 years (range, 52.3-70.6 years) had 60-min dynamic 18F-PET scans of the lumbar spine and proximal femur 2 weeks apart. The femoral artery IDAIF was obtained from the proximal femur scan using four different algorithms: (a) fixed partial volume correction (PVC) method; (b) variable PVC method; (c) Chen method; and (d) Cook-Lodge method. The aorta IDAIF was obtained from the lumbar spine scan using a previously validated method and the respective Ki values in the hip were used to assess the performance of each of the femoral artery algorithms.
When the femoral artery IDAIF methods were compared with the aorta IDAIF in terms of the area under the curve AUC values calculated in 4-min time intervals over 0-60 min, the absolute root mean square errors were: (a) fixed PVC, 0.52; (b) variable PVC, 0.54; (c) Chen, 0.72; and (d) Cook-Lodge, 0.49 in MBq s/ml. There were small, but statistically significant differences, in the Ki values found by all four femoral artery IDAIF methods when compared with the figures obtained using the aorta IDAIF. Bland-Altman plots of Ki values showed the best agreement for the fixed PVC method with a standard deviation of 0.0020 ml/min/ml, followed by variable PVC, Cook-Lodge and Chen method with standard deviations of 0.0022, 0.0024 and 0.0042 ml/min/ml, respectively.
We have demonstrated that it is possible to measure regional bone turnover at the hip without the need to perform direct arterial sampling to acquire the arterial input function (AIF). The differences in the Ki values obtained at the hip by using aorta IDAIF and any of the four image-based AIF methods at the femoral artery were small and clinically insignificant. The performance of fixed PVC, variable PVC and Cook-Lodge method was similar although the latter was less robust than the other two methods.
Nuclear Medicine Communications 09/2011; 32(9):808-17. · 1.40 Impact Factor
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ABSTRACT: (i) To validate two new image-based methods for finding the plasma arterial input function (AIF) and evaluate the performance of these and two similar techniques against arterial sampling. (ii) To evaluate the performance of all four image-derived AIF (IDAIF) methods against arterial sampling for measuring the F plasma clearance (Ki) to the lumbar spine.
Eight healthy postmenopausal women had a F-fluoride positron emission tomography scan of the lumbar spine. Venous blood samples were used to estimate the IDAIFs from: (i) a fixed population-based partial volume correction (PVC) factor method, (ii) a variable PVC factor method, (iii) the Chen method, and (iv) the Cook-Lodge method. Continuous arterial sampling and the respective Ki values were used as the gold standard against which the performance of the IDAIF methods was compared.
The IDAIFs were compared with direct arterial sampling in terms of the area under the curve values. The percentage root mean square error in area under the curves compared with arterial sampling were: (i) fixed PVC: 12.7%, (ii) variable PVC: 12.0%, (iii) Chen: 39.0%, and (iv) Cook-Lodge: 17.3%. There were small but significant differences in the Ki values found by all four methods compared with arterial sampling. Bland-Altman plots of Ki values showed the best agreement for the variable and fixed PVC methods with a standard deviation of 0.0026 and 0.0030 ml/min/ml, respectively.
The differences in the Ki values obtained at the lumbar spine using direct arterial sampling and any of the IDAIF methods at the aorta were clinically nonsignificant. The variable PVC and fixed PVC methods performed better than the Cook-Lodge and Chen methods.
Nuclear Medicine Communications 03/2011; 32(6):486-95. · 1.40 Impact Factor
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ABSTRACT: Bone scintigraphy (BS) lacks sensitivity for detecting very early skeletal metastases (SM) in prostate cancer (PC) and is often limited by poor specificity. Also scintigraphic flare of SM can occur following effective treatment and mislead an early response assessment. We hypothesised that a flare reaction might amplify the signal from subclinical SM, increasing the sensitivity of BS and that the phenomenon may be specific for metastases.
We conducted a prospective study to determine the frequency of the flare phenomenon in patients with metastatic PC starting hormone therapy and to explore its utility in patients with negative staging scans but considered at high risk of SM and in those with equivocal baseline BS abnormalities. Ninety-nine patients commencing first-line hormone therapy had repeat BS at 6 weeks to score a flare reaction.
Of 22 patients with unequivocal SM on the baseline scan, a flare occurred in 9 (41%). Of 36 high-risk localised prostate cancer patients with normal BS pre-treatment, the scan became positive for metastases at 6 weeks in 4 (11%). Of 41 patients with pre-treatment scintigraphic abnormalities of uncertain aetiology, a flare occurred in 8 cases (20%). All eight were confirmed to have SM by follow-up and imaging. Of the 33 remaining patients without a flare, 2 developed SM at 14 months and the remainder did not develop SM in a median follow-up period of 36 months.
The flare phenomenon following initial hormone therapy can be used to improve both sensitivity and specificity of BS in PC.
European Journal of Nuclear Medicine 01/2011; 38(1):7-13. · 4.53 Impact Factor
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ABSTRACT: The diphosphonate bone scan is ideally suited to assess many global, focal or multifocal metabolic bone disorders and there remains a role for conventional bone scintigraphy in metabolic bone disorders at diagnosis, investigation of complications, and treatment response assessment. In contrast, the role of bone scintigraphy in the evaluation of primary malignant bone tumors has reduced with the improvement of morphologic imaging, such as computed tomography and magnetic resonance imaging. However, an increasing role for (18)F-fluorodeoxyglucose positron emission tomography and positron emission tomography/computed tomography is emerging as a functional assessment at diagnosis, staging, and neoadjuvant treatment response assessment.
Seminars in nuclear medicine 01/2010; 40(1):52-61. · 3.96 Impact Factor
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Gary J R Cook
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ABSTRACT: Bone scintigraphy augmented with radiographs or cross-sectional imaging, such as computed tomography (CT) or magnetic resonance imaging (MRI), has remained the commonest method to diagnose and follow up skeletal metastases. However, bone scintigraphy is associated with relatively poor spatial resolution, limited diagnostic specificity and reduced sensitivity for bone marrow disease. It also shows limited diagnostic accuracy in assessing response to therapy in a clinically useful time period. With the advent of hybrid positron emission tomography (PET)/CT scanners there has been an increasing interest in using various PET tracers to evaluate skeletal disease including [(18)F]fluoride (NaF) as a bone-specific tracer and [(18)F]fluorodeoxyglucose and [(18)F]choline as tumour-specific tracers. There is also early work exploring the receptor status of skeletal metastases with somatostatin receptor analogues. This review describes the potential utility of these tracers in the assessment of skeletal metastases.
Cancer Imaging 01/2010; 10:1-8. · 1.50 Impact Factor
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ABSTRACT: In this review, we assess the current role of single-photon emission computed tomography (SPECT) and positron emission tomography (PET) in the imaging of skeletal metastatic disease from a miscellaneous group of malignancies, including lung, thyroid, and renal carcinomas; multiple myeloma; and neuroendocrine tumors, and consider how recent advances may enhance their effectiveness in this area. Bone scintigraphy using technetium-labeled diphosphonates has long been the mainstay of functional imaging of bony metastases, but is of limited value in myeloma and aggressive osteolytic metastases, and has the limitation of relatively poor specificity. SPECT, as a tomographic imaging technique, produces three-dimensional images of tracer distribution from multiplanar images. Its application to bone scintigrams greatly aids accurate anatomic localization and sensitivity in detection of foci of tracer uptake. SPECT can equally be applied to scintigrams using radiotracers, which are specific for particular groups of tumors, such as somatostatin analogs for neuroendocrine tumors. The advent of combined SPECT/computed tomography (CT) systems has further enhanced the accuracy of SPECT in all these malignancies. PET uses positron-emitting radiotracers and achieves a higher spatial resolution than single-photon imaging. Its high resolution and coverage of the entire body have made it a highly effective technique for the evaluation of skeletal metastatic disease, particularly when combined with CT. (18)F-fluorodeoxyglucose ((18)F-FDG)-PET/CT now forms part of routine staging for many carcinomas, such as non-small-cell lung carcinomas, and may obviate the need for routine staging scintigraphy in these patients. As uptake of the most common PET radiotracer, (18)F-FDG, is dependent on the increased cellular metabolism of most tumors, it may enable earlier detection of metastatic foci than bone scintigraphy, which relies on detecting an osteoblastic response. Another significant advantage of (18)F-FDG-PET is that it can detect soft-tissue components of metastases, which is particularly important in aggressive osteolytic metastases. The effectiveness of (18)F-FDG-PET is limited in slow-growing tumor types, but (18)F-sodium fluoride, a bone radiotracer that can detect early osteoblastic changes, shows promise in this area. Bony metastases from many neuroendocrine tumors can be detected with a high degree of specificity by PET using somatostatin analogs. Other novel and often highly specific radiotracers are under evaluation, which will further enhance the diagnostic capability of PET. The true potential of PET in this group of malignancies is gradually unfolding, although studied series of patients remain generally small and much further evaluation of its role is required.
Seminars in nuclear medicine 11/2009; 39(6):416-30. · 3.96 Impact Factor
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ABSTRACT: The functional imaging technique of (18)F-fluoride positron emission tomography ((18)F-PET) allows the non-invasive assessment of regional bone blood perfusion and turnover. Bone perfusion and turnover measured using (18)F-PET correlate closely with those obtained experimentally and so they can be readily applied in clinical research studies. The aim of this study was to compare bone perfusion and turnover between the lumbar spine and humerus in both treatment naïve postmenopausal women (n=11) and those on stable antiresorptive therapy (n=12). All women had a BMD T-score of less than -2 at the spine and/or hip. Each woman had a dynamic PET scan of the lumbar spine and distal humerus after injection of 90 MBq (18)F-fluoride. Using a three-compartmental model bone perfusion (K(1)), the net plasma clearance of tracer to bone mineral (K(i)) reflecting regional bone turnover and the rate constants k(2)-k(4) describing the transport of fluoride between plasma, an extravascular bone compartment and bone mineral compartment were calculated. Mean bone perfusion (K(1)) and bone turnover (K(i)) were significantly higher at the lumbar spine compared to the humerus for both treatment-naïve and antiresorptive groups. K(1) values were on average 3 times greater while K(i) was approximately 50% greater at the lumbar spine. The rate constant k(2), the reverse transport of fluoride from the extravascular compartment to plasma, was significantly lower at the humerus compared to the lumbar spine in both groups. The ratio K(i)/K(1) describing the unidirectional extraction efficiency to bone mineral was significantly greater at the humerus compared to the lumbar spine for both study groups. No significant differences between skeletal sites were observed for k(3) or k(4). In conclusion a significant skeletal heterogeneity was observed in terms of bone perfusion and turnover between the lumbar spine and humerus. (18)F-PET may aid in our understanding of the importance of bone perfusion in osteoporosis and differences in regional bone turnover with disease and in response to therapy.
Bone 09/2009; 45(5):942-8. · 4.02 Impact Factor
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ABSTRACT: (18)F-Fluoride PET allows noninvasive evaluation of regional bone metabolism and has the potential to become a useful tool for assessing patients with metabolic bone disease and evaluating novel drugs being developed for these diseases. The main PET parameter of interest, termed K(i), reflects regional bone metabolism. The aim of this study was to compare the long-term precision of (18)F-fluoride PET with that of biochemical markers of bone turnover assessed over 6 mo.
Sixteen postmenopausal women with osteoporosis or significant osteopenia and a mean age of 64 y underwent (18)F-fluoride PET of the lumbar spine and measurements of biochemical markers of bone formation (bone-specific alkaline phosphatase and osteocalcin) and bone resorption (urinary deoxypyridinoline) at baseline and 6 mo later. Four different methods for analyzing the (18)F-fluoride PET data were compared: a 4k 3-compartmental model using nonlinear regression analysis (K(i-4k)), a 3k 3-compartmental model using nonlinear regression analysis (K(i-3k)), Patlak analysis (K(i-PAT)), and standardized uptake values.
With the exception of a small but significant decrease in K(i-3k) at 6 mo, there were no significant differences between the baseline and 6-mo values for the PET parameters or biochemical markers. The long-term precision, expressed as the coefficient of variation (with 95% confidence interval in parentheses), was 12.2% (9%-19%), 13.8% (10%-22%), 14.4% (11%-22%), and 26.6% (19%-40%) for K(i-3k), K(i-PAT), mean standardized uptake value, and K(i-4k), respectively. For comparison, the precision of the biochemical markers was 10% (7%-15%), 18% (13%-27%), and 14% (10%-21%) for bone-specific alkaline phosphatase, osteocalcin, and urinary deoxypyridinoline, respectively. Intraclass correlation between the baseline and 6-mo values ranged from 0.44 for K(i-4k) to 0.85 for K(i-3k). No significant correlation was found between the repeated mean standardized uptake value measurements.
The precision and intraclass correlation observed for K(i-3k) and K(i-PAT) was equivalent to that observed for biochemical markers. This study provided initial data on the long-term precision of (18)F-fluoride PET measured at the lumbar spine, which will aid in the accurate interpretation of changes in regional bone metabolism in response to treatment.
Journal of Nuclear Medicine 06/2008; 49(5):700-7. · 6.38 Impact Factor
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ABSTRACT: The role for PET imaging of the skeleton is evolving. It is possible that 18F-fluoride PET may have incremental value in detecting bone metastases over conventional bone scintigraphy, but this has yet
to be established. A role may also exist for quantitative studies using 18F-fluoride PET for research or clinical applications where there is a need to quantify regional skeletal metabolism.
FDG-PET is highly sensitive for detecting skeletal metastases in most cancers, and it is possible that the use of conventional
bone scintigraphy may diminish as FDGPET is used more routinely for cancer staging. There is a developing role for the use
of this method also in primary bone tumors and in the detection of infection related to the skeleton.
10/2006: pages 317-335;
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ABSTRACT: Increasing access to positron emission tomography-computed tomography (PET-CT) has resulted in a shift towards functional imaging, being the primary tool in the assessment of viable tumour in oncology patients. In this review, we discuss the basic principles of this evolving technology and the radio-isotopes it employs. The main clinical applications of PET-CT are reviewed and some of the limitations of the technique are highlighted. Finally, we offer insight into possible future developments and how these modify current practice.
British Medical Bulletin 02/2006; 79-80:171-86. · 4.54 Impact Factor
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The Lancet Oncology 09/2004; 5(8):467-8. · 22.59 Impact Factor
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ABSTRACT: It is estimated that in excess of one million positron emission tomography (PET) scans are performed each year and PET can now truly be regarded as a routine imaging procedure in clinical management. Many potential pitfalls and artifacts have previously been described with (18)F-fluorodeoxyglucose PET imaging, but more continue to become apparent as worldwide experience increases. In addition, the advent of combined PET/CT scanners in clinical imaging practice has brought their own specific pitfalls and artifacts. It is essential that we learn these potential pitfalls so that patients can be optimally prepared for their scans and that accurate interpretation can be made.
Seminars in Nuclear Medicine 05/2004; 34(2):122-33. · 4.31 Impact Factor
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ABSTRACT: The effect of risedronate on bone metabolism at the lumbar spine was assessed in 18 women who had a 18F-fluoride PET scan at baseline and after 6 months of therapy. The net plasma clearance of fluoride to bone mineral reflecting osteoblastic activity decreased significantly after therapy.
Quantitative radionuclide studies of bone reflect bone blood flow and regional osteoblastic activity, and the latter should change after treatment with a bisphosphonate, although this has not been previously demonstrated. The aim of this study was to examine regional 18F-fluoride kinetics in the lumbar spine measured by 18F-fluoride positron emission tomography (PET) before and after treatment with risedronate.
Eighteen women, with a mean age of 67.0 years and a T-score of less than -2 at the spine or hip, had a dynamic PET scan of the lumbar spine after the injection of 90 MBq 18F-fluoride ion at baseline and 6 months after commencing risedronate therapy. The arterial plasma input function was derived using aorta arterial activity from the PET image. Time-activity curves were measured by placing regions of interest over the lumbar vertebrae. A three-compartmental model was used to calculate bone blood flow (K(1)) and the net plasma clearance of tracer to bone mineral (K(i)). Rate constants k(2), k(3), and k(4), which describe transport between plasma, the extracellular fluid (ECF) compartment, and the bone mineral compartment, respectively, were also measured.
Mean vertebral K(i) decreased significantly by 18.4% from baseline (3.32 x 10(-2) ml/min/ml) to 6 months post-treatment (2.71 x 10(-2) ml/min/ml; p = 0.04). This decrease was similar in magnitude to the decrease observed for bone-specific alkaline phosphatase, a marker of bone formation. There was no significant difference in K(1) from baseline (1.49 x 10(-1) ml/min/ml) to 6 months after treatment (1.38 x 10(-1) ml/min/ml; p > 0.05). There was a significant increase in k(2), reflecting the reverse transport of fluoride from the extravascular tissue compartment to plasma, after 6 months of treatment (2.90 x 10(-1)/min versus 4.43 x 10(-1)/min; p = 0.01). No significant changes were seen for k(3) or k(4). There was a significant decrease from baseline in the fraction of tracer in the extravascular tissue space that underwent specific binding to the bone matrix (k(3)/[k(2) + k(3)]), decreasing by 18.1% (p = 0.02).
K(i), the net plasma clearance to bone mineral reflecting regional osteoblastic activity, displayed a significant decrease after 6 months of antiresorptive therapy. This is the first study to show a direct metabolic effect of antiresorptive therapy on skeletal kinetics at the clinically important site of the lumbar spine. The use of 18F-fluoride PET may provide a useful noninvasive tool to assess novel treatments currently being developed for osteoporosis.
Journal of Bone and Mineral Research 01/2004; 18(12):2215-22. · 6.37 Impact Factor
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New England Journal of Medicine 07/2003; 348(25):2487-8. · 53.30 Impact Factor
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ABSTRACT: To measure regional skeletal kinetics using fluorine-18 fluoride positron emission tomography (PET) it is necessary to know
the concentration of radioactive tracer being delivered to bone by arterial plasma with relation to time, the arterial input
function (IFa). Methods by which IFa can be derived without arterial sampling are attractive because of their relative technical
simplicity and the reduction in possible morbidity to the subject. We have compared the use of a scaled population input function
(IFp) and a corrected image-derived input function from the aorta (IFi) with an IFa directly measured from a radial artery
line in ten normal postmenopausal women. Both of the aforementioned methods rely only on a small number of discrete venous
samples. Each subject had a dynamic PET acquisition of the lumbar spine performed after the intravenous injection of 180 MBq
18F-fluoride. Both the IFp and the IFi were compared with the IFa in terms of the accuracy of determination of six parameters.
These were: plasma clearance of fluoride to bone mineral (K
i), unidirectional plasma clearance to total bone tissue (K
1) and individual rate constants k
2, k
3 and k
4, calculated using non-linear regression with a three-compartment model, and the plasma clearance to bone mineral calculated
using the Patlak method (K
pat). For both the IFp and the IFi method the root mean square errors for K
pat and K
i were similar and small (<8.2%). The errors in determining K
1 and the rate constants k
2 to k
4 are larger by either method, but with a small advantage using the IFp method. It is concluded that the use of either non-invasive
method for determining the arterial plasma input function is suitable for the measurement of the most important parameters,
K
i and K
pat, in these subjects.
European journal of nuclear medicine and molecular imaging 09/1999; 26(11):1424-1429. · 4.99 Impact Factor
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ABSTRACT: Interpretation of studies from all imaging modalities requires a knowledge of the possible pitfalls that may occur due to
normal variation, artefacts and processes which may mimic pathology. The applications and use of not only 18-fluoro-2-deoxyglucose
but also l-[methyl-11C] methionine positron emission tomography (PET) are widening and it is timely that the currently recognised interpretative
pitfalls are reviewed as the number of dedicated PET scanners and coincidence gamma cameras increases.
European journal of nuclear medicine and molecular imaging 08/1999; 26(10):1363-1378. · 4.99 Impact Factor
