Diagnostic performance of 18F-dihydroxyphenylalanine positron emission tomography in patients with paraganglioma: a meta-analysis

Purpose

The aim of this study was to systematically review and conduct a meta-analysis of published data about the diagnostic performance of ¹⁸F-dihydroxyphenylalanine (DOPA) positron emission tomography (PET) in patients with paraganglioma (PG).

Methods

A comprehensive computer literature search of studies published through 30 June 2011 regarding ¹⁸F-DOPA PET or PET/computed tomography (PET/CT) in patients with PG was performed in PubMed/MEDLINE, Embase and Scopus databases. Pooled sensitivity and specificity of ¹⁸F-DOPA PET or PET/CT in patients with PG on a per patient- and on a per lesion-based analysis were calculated. The area under the receiver-operating characteristic (ROC) curve was calculated to measure the accuracy of ¹⁸F-DOPA PET or PET/CT in patients with PG. Furthermore, a sub-analysis taking into account the different genetic mutations in PG patients was also performed.

Results

Eleven studies comprising 275 patients with suspected PG were included in this meta-analysis. The pooled sensitivity of ¹⁸F-DOPA PET and PET/CT in detecting PG was 91% [95% confidence interval (CI) 87–94%] on a per patient-based analysis and 79% (95% CI 76–81%) on a per lesion-based analysis. The pooled specificity of ¹⁸F-DOPA PET and PET/CT in detecting PG was 95% (95% CI 86–99%) on a per patient-based analysis and 95% (95% CI 84–99%) on a per lesion-based analysis. The area under the ROC curve was 0.95 on a per patient- and 0.94 on a per lesion-based analysis. Heterogeneity between the studies about sensitivity of ¹⁸F-DOPA PET or PET/CT was found. A significant increase in sensitivity of ¹⁸F-DOPA PET or PET/CT was observed when a sub-analysis excluding patients with succinate dehydrogenase subunit B (SDHB) gene mutations was performed.

Conclusion

In patients with suspected PG ¹⁸F-DOPA PET or PET/CT demonstrated high sensitivity and specificity. ¹⁸F-DOPA PET or PET/CT are accurate methods in this setting. Nevertheless, possible sources of false-negative results should be kept in mind. Furthermore, SDHB gene mutations could influence ¹⁸F-DOPA PET or PET/CT diagnostic performance.     

Comparison of 18F-DOPA, 18F-FDG and 68Ga-somatostatin analogue PET/CT in patients with recurrent medullary thyroid carcinoma

Purpose

To retrospectively evaluate and compare ¹⁸F-FDG, ¹⁸F-DOPA and ⁶⁸Ga-somatostatin analogues for PET/CT in patients with residual/recurrent medullary thyroid carcinoma (MTC) suspected on the basis of elevated serum calcitonin levels.

Methods

Included in the study were 18 patients with recurrent MTC in whom functional imaging with the three tracers was performed. The PET/CT results were compared on a per-patient basis and on a per-lesion-basis.

Results

At least one focus of abnormal uptake was observed on PET/CT in 13 patients with ¹⁸F-DOPA (72.2% sensitivity), in 6 patients with ⁶⁸Ga-somatostatin analogues (33.3%) and in 3 patients with ¹⁸F-FDG (16.7%) (p?18F-DOPA and ¹⁸F-FDG PET/CT (p?18F-DOPA and ⁶⁸Ga-somatostatin analogue PET/CT (p?=?0.04). Overall, 72 lesions were identified on PET/CT with the three tracers. ¹⁸F-DOPA PET/CT detected 85% of lesions (61 of 72), ⁶⁸Ga-somatostatin analogue PET/CT 20% (14 of 72) and ¹⁸F-FDG PET/CT 28% (20 of 72). There was a statistically significant difference in the number of lymph node, liver and bone lesions detected with the three tracers (p?18F-DOPA PET/CT and ¹⁸F-FDG PET/CT (p?18F-DOPA PET/CT and ⁶⁸Ga-somatostatin analogue PET/CT (p?Conclusion ¹⁸F-DOPA PET/CT seems to be the most useful imaging method for detecting recurrent MTC lesions in patients with elevated serum calcitonin levels, performing better than ¹⁸F-FDG and ⁶⁸Ga-somatostatin analogue PET/CT. ¹⁸F-FDG may complement ¹⁸F-DOPA in patients with an aggressive tumour.     

A retrospective comparison between 68Ga-DOTA-TOC PET/CT and 18F-DOPA PET/CT in patients with extra-adrenal paraganglioma

Purpose

¹⁸F-Fluoro-l-dihydroxyphenylalanine (¹⁸F-DOPA) PET offers high sensitivity and specificity in the imaging of nonmetastatic extra-adrenal paragangliomas (PGL) but lower sensitivity in metastatic or multifocal disease. These tumours are of neuroendocrine origin and can be detected by ⁶⁸Ga-DOTA-Tyr³-octreotide (⁶⁸Ga-DOTA-TOC) PET. Therefore, we compared ⁶⁸Ga-DOTA-TOC and ¹⁸F-DOPA as radiolabels for PET/CT imaging for the diagnosis and staging of extra-adrenal PGL. Combined cross-sectional imaging was the reference standard.

Methods

A total of 5 men and 15 women (age range 22 to 73 years) with anatomical and/or histologically proven extra-adrenal PGL were included in this study. Of these patients, 5 had metastatic or multifocal lesions and 15 had single sites of disease. Comparative evaluation included morphological imaging with CT and functional imaging with ⁶⁸Ga-DOTA-TOC PET and ¹⁸F-DOPA PET. The imaging results were analysed on a per-patient and a per-lesion basis. The maximum standardized uptake value (SUV_max) of each functional imaging modality in concordant tumour lesions was measured.

Results

Compared with anatomical imaging, ⁶⁸Ga-DOTA-TOC PET and ¹⁸F-DOPA PET each had a per-patient and per-lesion detection rate of 100 % in nonmetastatic extra-adrenal PGL. However, in metastatic or multifocal disease, the per-lesion detection rate of ⁶⁸Ga-DOTA-TOC was 100 % and that of ¹⁸F-DOPA PET was 56.0 %. Overall, ⁶⁸Ga-DOTA-TOC PET identified 45 lesions; anatomical imaging identified 43 lesions, and ¹⁸F-DOPA PET identified 32 lesions. The overall per-lesion detection rate of ⁶⁸Ga-DOTA-TOC PET was 100 % (McNemar, P?<?0.5), and that of ¹⁸F-DOPA PET was 71.1 % (McNemar, P?<?0.001). The SUV_max (mean ± SD) of all 32 concordant lesions was 67.9?±?61.5 for ⁶⁸Ga-DOTA-TOC PET and 11.8?±?7.9 for ¹⁸F-DOPA PET (Mann-Whitney U test, P?<?0.0001).

Conclusion

⁶⁸Ga-DOTA-TOC PET may be superior to ¹⁸F-DOPA PET and diagnostic CT in providing valuable information for pretherapeutic staging of extra-adrenal PGL, particularly in surgically inoperable tumours and metastatic or multifocal disease.     

Ability of <Superscript>18</Superscript>F-DOPA PET/CT and fused <Superscript>18</Superscript>F-DOPA PET/MRI to assess striatal involvement in paediatric glioma

Purpose

To assess the diagnostic performance of ¹⁸F-DOPA PET/CT and fused ¹⁸F-DOPA PET/MRI in detecting striatal involvement in children with gliomas.

Methods

This retrospective study included 28 paediatric patients referred to our institution for the presence of primary, residual or recurrent glioma (12 boys, 16 girls; mean age 10.7 years) and investigated with ¹⁸F-DOPA PET/CT and brain MRI. Fused ¹⁸F-DOPA PET/MR images were obtained and compared with PET/CT and MRI images. Accuracy, sensitivity, specificity, negative predictive value (NPV) and positive predictive value (PPV) for striatal involvement were calculated for each diagnostic tool. Univariate and multivariate logistic analyses were applied to evaluate the associations between ¹⁸F-DOPA PET/CT and fused ¹⁸F-DOPA PET/MRI diagnostic results and tumour uptake outside the striatum, grade, dimension and site of striatal involvement (ventral and/or dorsal).

Results

Accuracy, sensitivity, specificity, PPV, and NPV were 100 % for MRI, 93 %, 89 %, 100 %, 100 % and 82 % for ¹⁸F-DOPA PET/MRI, and 75 %, 74 %, 78 %, 88 % and 58 % for ¹⁸F-DOPA PET/CT, respectively. ¹⁸F-DOPA PET/MRI showed a trend towards higher accuracy compared with ¹⁸F-DOPA PET/CT (p?=?0.06). MRI showed significantly higher accuracy compared with ¹⁸F-DOPA PET/CT (p?=?0.01), but there was no significant difference between MRI and ¹⁸F-DOPA PET/MRI. Both univariate and multivariate logistic analyses showed a significant association (OR 8.0 and 7.7, respectively) between the tumour-to-normal striatal uptake (T/S) ratio and the diagnostic ability of ¹⁸F-DOPA PET/CT (p?=?0.03). A strong significant association was also found between involvement of the dorsal striatum and the ¹⁸F-DOPA PET/CT results (p?=?0.001), with a perfect prediction of involvement of the dorsal striatum by ¹⁸F-DOPA PET/MRI.

Conclusion

Physiological striatal ¹⁸F-DOPA uptake does not appear to be a main limitation in the evaluation of basal ganglia involvement.¹⁸F-DOPA PET/CT correctly detected involvement of the dorsal striatum in lesions with a T/S ratio >1, but appeared to be less suitable for evaluation of the ventral striatum. The use of fused ¹⁸F-DOPA PET/MRI further improves the accuracy and is essential for evaluation of the ventral striatum.

     

Diagnostic utility of PET/CT with <Superscript>18</Superscript>F-DOPA and <Superscript>18</Superscript>F-FDG in persistent or recurrent medullary thyroid carcinoma: the importance of calcitonin and carcinoembryonic antigen cutoff

Purpose

This study sought to evaluate and compare the utility of 18-F-fluorodihydroxyphenylalanine (¹⁸F-DOPA) and 18-F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) for identification of lesions in patients with recurrent medullary thyroid carcinoma (MTC). In addition, we analyzed the correlation between the calcitonin (Ct), carcinoembryonic antigen (CEA) levels, each doubling time (DT), and PET positivity. We evaluated the reliability of the 150 pg/mL Ct cutoff set by the American Thyroid Association guidelines for further imaging (including ¹⁸F-DOPA PET/CT).

Methods

We prospectively recruited 18 patients with recurrent MTC, identified by elevation of Ct or CEA. Each patient underwent a ¹⁸F-FDG PET/CT and a ¹⁸F-DOPA PET/CT.

Results

Abnormal uptakes were detected with ¹⁸F-DOPA (n=12) and ¹⁸F-FDG (n=9), (sensitivity of 66.7% vs. 50%; p<0.01). Twenty-eight lesions were detected with ¹⁸F-DOPA vs. 16 lesions with ¹⁸F-FDG (1.56±1.5 vs. 0.89±1.18 lesions per patient; p=0.01). None of our patients showed additional lesions with ¹⁸F-FDG in comparison to ¹⁸F-DOPA. Patient-based detection rate increased significantly with Ct levels ≥150 pg/mL vs. Ct<150 pg/mL for both ¹⁸F-DOPA (sensitivity 90.9% vs. 28.6%; p=0.013) and ¹⁸F-FDG PET/CT (sensitivity 72.7% vs. 14.3%; p=0.025). Using a CEA cutoff of ≥5 ng/mL, detection rates of ¹⁸F-DOPA and ¹⁸F-FDG PET/CT were 81.1% and 72.7%, respectively. No correlation between Ct-DT or CEA-DT and PET positivity was found. Histological confirmation was obtained in eight patients.

Conclusions

¹⁸F-DOPA PET/CT appears to be superior to ¹⁸F-FDG PET/CT in detecting and locating lesions in patients with recurrent MTC. This technique tends to be especially useful in patients with negative results in other imaging modalities and Ct≥150 pg/mL or CEA≥5 ng/mL.

     

Compared to <Superscript>123</Superscript>I-MIBG SPECT/CT, <Superscript>18</Superscript>F-DOPA PET/CT provides accurate tumor extent in patients with extra-adrenal paraganglioma

Aim

The aim of this study was to compare the accuracy of ¹²³I-MIBG SPECT/CT with that of ¹⁸F-DOPA PET/CT for staging extra-adrenal paragangliomas (PGLs) using both functional and anatomical images (i.e., combined cross-sectional imaging) as the reference standards.

Methods

Three men and seven women (age range 26–73 years) with anatomical and/or histologically proven disease were included in this study. Three patients had either metastatic head-and-neck paragangliomas (HNPGLs) or multifocal PGL, and seven patients had nonmetastatic disease. Comparative evaluation included morphological imaging with CT, functional imaging with ¹⁸F-DOPA PET, and ¹²³I-MIBG imaging including SPECT/CT. Imaging results were analyzed on a per-patient and per-lesion basis.

Results

On a per-patient basis, ¹⁸F-DOPA PET’s detection rate for both nonmetastatic and metastatic/multifocal disease was 100%, whereas that of planar ¹²³I-MIBG imaging alone was 10.0% and that of ¹²³I-MIBG SPECT/CT was 20.0%. Overall, on a per-lesion basis, ¹⁸F-DOPA PET showed a sensitivity of 69.2% (McNemar p?<?0.001) compared with anatomical imaging. Sensitivity of planar ¹²³I-MIBG scintigraphy was 5.6%, and that of SPECT/CT was 11.1% (McNemar p?<?0.0001). Overall, ¹⁸F-DOPA PET identified 18 lesions, and anatomical imaging identified 26 lesions; planar ¹²³IMIBG imaging identified only 1 lesion, and SPECT/CT, 2 lesions.

Conclusion

¹⁸F-DOPA PET is more sensitive than is ¹²³I-MIBG imaging, including SPECT/CT, for staging HNPGL. Combined functional and anatomical imaging (PET/CT) is indicated to exclude metastatic disease in extra-adrenal PGL.

     

Prognostic value of 18F-DOPA PET/CT at the time of recurrence in patients affected by neuroblastoma

Purpose

The aim of this study was to investigate the relationship between ¹²³I-metaiodobenzylguanidine (MIBG) scan semi-quantification and a new ¹⁸F-DOPA positron emission tomography (PET)/CT score in patients with suspected or documented neuroblastoma (NB) relapse and to assess the association between these two parameters and progression-free survival (PFS)/overall survival (OS).

Methods

We analysed 24 NB patients who had undergone ¹²³I-MIBG and ¹⁸F-DOPA PET/CT scans at the time of suspected relapse, after applying a proper scoring system for each scan. In time-to-event analyses, the score distributions were regarded as continuous and were categorized in tertiles and medians. We used Kaplan-Meier curves and Cox proportional hazard models for PFS and OS in order to estimate the independent prognostic impact of ¹²³I-MIBG and ¹⁸F-DOPA PET/CT scans.

Results

The ¹²³I-MIBG and ¹⁸F-DOPA scores were highly and positively correlated (Spearman’s rho?=?0.8, p?<?0.001). Over a median follow-up of 14 months (range 6–82), 12 cases of disease progression and 6 deaths occurred. Multivariate Cox models showed a higher risk of disease progression [hazard ratio (HR) 17.0, 95 % confidence interval (CI) 2.7–109] in NB patients with ¹²³I-MIBG score?>?3 (3rd tertile) and an even higher risk (HR:37.2, 95 % CI 2.4–574) in those with ¹⁸F-DOPA whole-body metabolic burden (WBMB) >7.5 (median), after adjustment for all main clinical/pathological factors considered. Kaplan-Meier analyses showed a significant association with OS (log-rank p?=?0.01 and p?=?0.03 for ¹²³I-MIBG and ¹⁸F-DOPA WBMB, respectively).

Conclusion

Our results confirm the good agreement between ¹⁸F-DOPA PET/CT and ¹²³I-MIBG scan in patients affected by NB relapse. In time-to-event analyses, ¹²³I-MIBG scan and ¹⁸F-DOPA PET/CT scores were independently and significantly associated with disease progression.     

18F-DOPA PET/CT and 68Ga-DOTANOC PET/CT scans as diagnostic tools in focal congenital hyperinsulinism: a blinded evaluation

Purpose

Focal congenital hyperinsulinism (CHI) is curable by surgery, which is why identification of the focal lesion is crucial. We aimed to determine the use of 18F–fluoro-dihydroxyphenylalanine (18F-DOPA) PET/CT vs. 68Ga-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic-acid-1-Nal3-octreotide (68Ga-DOTANOC) PET/CT as diagnostic tools in focal CHI.

Methods

PET/CT scans of children with CHI admitted to Odense University Hospital between August 2005 and June 2016 were retrospectively evaluated visually and by their maximal standardized uptake values (SUV_max) by two independent examiners, blinded for clinical, surgical and pathological data. Pancreatic histology was used as the gold standard. For patients without surgery, the genetic profile served as the gold standard.

Results

Fifty-five CHI patients were examined by PET/CT (18F-DOPA n = 53, 68Ga-DOTANOC n = 18). Surgery was performed in 34 patients, no surgery in 21 patients. Fifty-one patients had a classifiable outcome, either by histology (n = 33, 22 focal lesions, 11 non-focal) or by genetics (n = 18, all non-focal). The predictive performance of 18F-DOPA PET/CT to identify focal CHI was identical by visual- and cut-off-based evaluation: sensitivity (95% CI) of 1 (0.85–1); specificity of 0.96 (0.82–0.99). The optimal 18F-DOPA PET SUV_max ratio cut-off was 1.44 and the optimal 68Ga-DOTANOC PET SUV_max cut-off was 6.77 g/ml. The area under the receiver operating curve was 0.98 (0.93–1) for 18F-DOPA PET vs. 0.71 (0.43–0.95) for 68Ga-DOTANOC PET (p < 0.03). In patients subjected to surgery, localization of the focal lesion was correct in 91%, and 100%, by 18F-DOPA PET/CT and 68Ga-DOTANOC PET/CT, respectively.

Conclusion

18F-DOPA PET/CT was excellent in predicting focal CHI and superior compared to 68Ga-DOTANOC PET/CT. Further use of 68GA-DOTANOC PET/CT in predicting focal CHI is discouraged.

     

<Superscript>18</Superscript>F-DOPA PET/CT in the diagnosis and localization of persistent medullary thyroid carcinoma

Purpose

To evaluate the performance of ¹⁸F-l-dihydroxyphenylalanine (¹⁸F-DOPA) PET/CT in the detection of locoregional and distant medullary thyroid carcinoma (MTC) metastases and to compare imaging findings with histological data.

Methods

We retrospectively evaluated 86 MTC patients with persistently high serum calcitonin levels after initial surgery who had undergone ¹⁸F-DOPA PET/CT between January 2007 and December 2014 in two referral centres. They were followed up for at least 6 months after the PET/CT assessment. The results were compared with histological data or with the findings obtained during follow-up using a complementary imaging modality.

Results

¹⁸F-DOPA PET/CT was positive in 65 of the 86 patients, corresponding to a patient-based sensitivity of 75.6 %. Distant metastatic disease (M1) was seen in 29 patients including 11 with previously unknown metastases revealed only by PET/CT. Among the 36 patients without distant metastatic spread, 25 had nodal involvement limited to the neck, and 10 of these 25 patients underwent reoperation. The lymph node compartment-based sensitivity of ¹⁸F-DOPA PET/CT was 100 % in the two institutions but lesion-based sensitivity was only 24 %. Preoperative and postoperative median calcitonin levels were 405 pg/mL (range 128 – 1,960 pg/mL) and 259 pg/mL (range 33 – 1,516 pg/mL), respectively. None of the patients achieved normalization of serum calcitonin after reoperation.

Conclusion

¹⁸F-DOPA PET/CT enables early diagnosis of a significant number of patients with distant metastasis. It has a limited sensitivity in the detection of residual disease but provides high performance for regional analysis. A surgical compartment-oriented approach could be the approach of choice whatever the number of nodes revealed by ¹⁸F-DOPA PET/CT.

     

Predictive and prognostic value of 18F-DOPA PET/CT in patients affected by recurrent medullary carcinoma of the thyroid

Introduction

Medullary thyroid carcinoma (MTC) is a malignancy accounting for about 5–8% of thyroid cancers. Serum calcitonin and carcinoembryonic antigen (CEA) levels are widely used to monitor disease progression. However, prognostic factors able to predict outcomes are highly desirable. We, therefore, aimed to assess the prognostic role of ¹⁸F-DOPA PET/CT in patients with recurrent MTC.

Materials and methods

60 patients (mean age 64?±?13 years, range 44–82) with recurrent MTC were eligible from a multicenter database. All patients underwent a restaging ¹⁸F-DOPA PET/CT, performed at least 6 months after surgery. CEA/calcitonin levels, local recurrences, nodal involvement and metastases at PET/CT were recorded. SUVmax, SUVmean (also normalized to mediastinal uptake) and metabolic tumor volume were automatically calculated for each lesion, by placing a volume of interest around the lesion with 40% of peak activity as threshold for the automatic contouring. The patients were clinically and radiologically followed up for 21?±?11 months. Rate of progression-free survival (PFS), disease-specific survival (DSS) and incremental prognostic value of ¹⁸F-DOPA PET/CT over conventional imaging modalities were assessed by Kaplan–Meier curves and Log-Rank test. Cox regression univariate and multivariate analyses were performed for assessing predictors of prognosis.

Results

¹⁸F-DOPA PET/CT showed abnormal findings in 27 patients (45%) and resulted unremarkable in 33 (55%). PFS was significantly longer in patients with an unremarkable PET/CT scan (p?=?0.018). Similarly, an unremarkable PET/CT study was associated with a significantly longer DSS (p?=?0.04). ¹⁸F-DOPA PET/CT added prognostic value over other imaging modalities both for PFS and for DSS (p?<?0.001 and p?=?0.012, respectively). Neither semiquantitative PET parameters nor clinical or laboratory data were predictive of a worse PFS and DSS in patients with recurrent MTC.

Conclusion

¹⁸F-DOPA PET/CT scan has an important prognostic value in predicting disease progression and mortality rate.

     

18F-Fluoride PET/CT is highly effective for excluding bone metastases even in patients with equivocal bone scintigraphy

Purpose

Bone scintigraphy (BS) has been used extensively for many years for the diagnosis of bone metastases despite its low specificity and significant rate of equivocal lesions. ¹⁸F-Fluoride PET/CT has been proven to have a high sensitivity and specificity in the detection of malignant bone lesions, but its effectiveness in patients with inconclusive lesions on BS is not well documented. This study evaluated the ability of ¹⁸F-fluoride PET/CT to exclude bone metastases in patients with various malignant primary tumours and nonspecific findings on BS.

Methods

We prospectively studied 42 patients (34–88?years of age, 26 women) with different types of tumour. All patients had BS performed for staging or restaging purposes but with inconclusive findings. All patients underwent ¹⁸F-fluoride PET/CT. All abnormalities identified on BS images were visually compared with their appearance on the PET/CT images.

Results

All the 96 inconclusive lesions found on BS images of the 42 patients were identified on PET/CT images. ¹⁸F-Fluoride PET/CT correctly excluded bone metastases in 23 patients (68 lesions). Of 19 patients (28 lesions) classified by PET/CT as having metastases, 3 (5 lesions) were finally classified as free of bone metastases on follow-up. The sensitivity, specificity, and positive and negative predictive values of ¹⁸F-fluoride PET/CT were, respectively, 100?%, 88?%, 84?% and 100?% for the identification of patients with metastases (patient analysis) and 100?%, 82?% and 100?% for the identification of metastatic lesions (lesion analysis).

Conclusion

The factors that make BS inconclusive do not affect ¹⁸F-fluoride PET/CT which shows a high sensitivity and negative predictive value for excluding bone metastases even in patients with inconclusive conventional BS.     

Usefulness of 18F-fluoride PET/CT in Breast Cancer Patients with Osteosclerotic Bone Metastases

Purpose

Bone metastasis is an important factor for the treatment and prognosis of breast cancer patients. Whole-body bone scintigraphy (WBBS) can evaluate skeletal metastases, and ¹⁸F-FDG PET/CT seems to exhibit high specificity and accuracy in detecting bone metastases. However, there is a limitation of ¹⁸F-FDG PET in assessing sclerotic bone metastases because some lesions may be undetectable. Recent studies showed that ¹⁸F-fluoride PET/CT is more sensitive than WBBS in detecting bone metastases. This study aims to evaluate the usefulness of ¹⁸F-fluoride PET/CT by comparing it with WBBS and ¹⁸F-FDG PET/CT in breast cancer patients with osteosclerotic skeletal metastases.

Materials and Methods

Nine breast cancer patients with suspected bone metastases (9 females; mean age ± SD, 55.6 ± 10.0 years) underwent ^99mTc-MDP WBBS, ¹⁸F-FDG PET/CT and ¹⁸F-fluoride PET/CT. Lesion-based analysis of five regions of the skeletons (skull, vertebral column, thoracic cage, pelvic bones and long bones of extremities) and patient-based analysis were performed.

Results

¹⁸F-fluoride PET/CT, ¹⁸F-FDG PET/CT and WBBS detected 49, 20 and 25 true metastases, respectively. Sensitivity, specificity, positive predictive value and negative predictive value of ¹⁸F-fluoride PET/CT were 94.2 %, 46.3 %, 57.7 % and 91.2 %, respectively. Most true metastatic lesions on ¹⁸F-fluoride PET/CT had osteosclerotic change (45/49, 91.8 %), and only four lesions showed osteolytic change. Most lesions on ¹⁸F-FDG PET/CT also demonstrated osteosclerotic change (17/20, 85.0 %) with three osteolytic lesions. All true metastatic lesions detected on WBBS and ¹⁸F-FDG PET/CT were identified on ¹⁸F-fluoride PET/CT.

Conclusion

¹⁸F-fluoride PET/CT is superior to WBBS or ¹⁸F-FDG PET/CT in detecting osteosclerotic metastatic lesions. ¹⁸F-fluoride PET/CT might be useful in evaluating osteosclerotic metastases in breast cancer patients.     

18F-fluorodeoxyglucose positron emission tomography and computed tomography in anaplastic thyroid cancer

Purpose

Our aim was to evaluate in anaplastic thyroid carcinoma (ATC) patients the value of ¹⁸F-FDG PET/CT compared with total body computed tomography (CT) using intravenous contrast material for initial staging, prognostic assessment, therapeutic monitoring and follow-up.

Methods

Twenty consecutive ATC patients underwent PET/CT for initial staging. PET/CT was performed again during follow-up. The gold standard was progression on imaging follow-up (CT or PET/CT) or confirmation with another imaging modality.

Results

A total of 265 lesions in 63 organs were depicted in 18 patients. Thirty-five per cent of involved organs were demonstrated only with PET/CT and one involved organ only with CT. In three patients, the extent of disease was significantly changed with PET/CT that demonstrated unknown metastases. Initial treatment modalities were modified by PET/CT findings in 25% of cases. The volume of FDG uptake (≥300 ml) and the intensity of FDG uptake (SUV_max ≥18) were significant prognostic factors for survival. PET/CT permitted an earlier assessment of tumour response to treatment than CT in 4 of the 11 patients in whom both examinations were performed. After treatment with combined radiotherapy and chemotherapy, only the two patients with a negative control PET/CT had a confirmed complete remission at 14 and 38 months; all eight patients who had persistent FDG uptake during treatment had a clinical recurrence and died.

Conclusion

FDG PET/CT appears to be the reference imaging modality for ATC at initial staging and seems promising in the early evaluation of treatment response and follow-up.     

Role of 18F-fluoride PET/CT in the assessment of multiple myeloma: initial experience

Purpose

The aim of this study was to report our early experience with ¹⁸F-fluoride PET/CT for detecting lesions and evaluate the usefulness of this modality in the assessment of multiple myeloma (MM).

Materials and methods

¹⁸F-fluoride PET/CT and ^99mTc-MDP bone scintigraphy (BS) studies from 7 myeloma patients (4 male and 3 female, mean age 55 years) diagnosed according to standard criteria were reviewed retrospectively. Two reviewers visually and quantitatively analyzed the images and recorded their findings after reaching a consensus. Diagnostic certainty regarding the presence or absence of myeloma lesions was evaluated according to the reference standard consisting of whole-body magnetic resonance imaging and whole-body X-ray.

Results

A total of 93 affected areas were definite according to the reference standard. Of these, 83 affected areas (89 %) were identified on ¹⁸F-fluoride PET/CT, whereas 54 affected areas (58 %) were found on BS. Mean SUVmax in the affected areas was 9.8 ± 3.2 (standard deviation) ranging from 5.0 to 21.2. A total of s17 lesions with bone fracture were also detected by ¹⁸F-fluoride PET/CT and 2 lesions (12 %) were negative on BS.

Conclusion

Our result showed that ¹⁸F-fluoride PET was a possible modality to detect areas of lesions in patients with MM.     

18F-FDG PET/CT changes therapy management in high-risk DTC after first radioiodine therapy

Purpose

Advanced tumour stage and initial metastases are associated with reduced general and tumour-free survival in patients with differentiated thyroid carcinoma. Optimal initial therapy is mandatory for a positive patient outcome, but can only be performed if all non-iodine-avid tumour lesions are known before planning treatment. We analysed the benefit of ¹⁸F-FDG PET/CT at initial diagnosis in patients with high-risk differentiated thyroid carcinoma and determined whether the ¹⁸F-FDG PET/CT results led to a deviation from the standard procedure, which consists of two consecutive radioiodine treatments with thyroid hormone suppression in between and no additional imaging, with individual patient management.

Methods

The study group comprised 90 consecutive patients with either extensive or metastasized high-risk differentiated thyroid carcinoma who received ¹⁸F-FDG PET/CT after the first radioiodine treatment approximately 4?weeks after thyroidectomy under endogenous TSH stimulation. We carried out PET/CT imaging with low-dose CT without contrast medium, which we only used for attenuation correction of PET images.

Results

¹⁸F-FDG PET/CT was positive in 26 patients (29%) and negative in 64 patients (71%). Compared to the results of posttherapeutic ¹³¹I whole-body scintigraphy, the same lesions were PET-positive in 7 of the 26 patients, different lesions were PET-positive in 15 patients, and some PET-positive lesions were the same and some were different in 4 patients. TNM staging was changed due to the PET results in 8 patients. Management was changed in 19 of the 90 patients (21%), including all patients with only FDG-positive lesions and all patients with both FDG-positive and iodine-positive lesions. Age was not a predictive factor for the presence of FDG-positive lesions. FDG-positive and iodine-positive lesions were associated with high serum thyroglobulin. However, at low serum thyroglobulin values, tumour lesions (iodine- and/or FDG-avid) were also diagnosed. Thus, the serum thyroglobulin value prior to the first radioiodine treatment cannot be used as a predictor of the presence of FDG-positive lesions.

Conclusion

¹⁸F-FDG PET/CT resulted in a change of therapeutic procedure in 11 of 90 patients and in a change of patient management through additional diagnostic measures in 8 of 90 patients, and is consequently very helpful in initial staging. At our hospital, ¹⁸F-FDG PET/CT in high-risk patients with differentiated thyroid carcinoma has been established as an initial staging modality.     

Whole-body [18F]FDG PET/MRI vs. PET/CT in the assessment of bone lesions in oncological patients: initial results

Objectives

To compare [¹⁸?F]FDG PET/MRI with PET/CT for the assessment of bone lesions in oncologic patients.

Methods

This prospective study included 67 patients with solid tumours scheduled for PET/CT with [¹⁸?F]FDG who also underwent a whole-body PET/MRI scan. The datasets (PET/CT, PET/MRI) were rated by two readers regarding lesion conspicuity (four-point scale) and diagnostic confidence (five-point scale). Median scores were compared using the Wilcoxon test.

Results

Bone metastases were present in ten patients (15 %), and benign bone lesions in 15 patients (22 %). Bone metastases were predominantly localized in the pelvis (18 lesions, 38 %) and the spine (14 lesions, 29 %). Benign bone lesions were exclusively osteosclerotic and smaller than the metastases (mean size 6 mm vs. 23 mm). While PET/CT allowed identification of 45 of 48 bone metastases (94 %), PET/MRI allowed identification of all bone metastases (100 %). Conspicuity of metastases was high for both modalities with significantly better results using PET/MRI (p?<?0.05). Diagnostic confidence in lesion detection was high for both modalities without a significant difference. In benign lesions, conspicuity and diagnostic confidence were significantly higher with PET/CT (p?<?0.05).

Conclusions

[¹⁸?F]FDG PET/MRI shows high potential for the assessment of bone metastases by offering superior lesion conspicuity when compared to PET/CT. In hypersclerotic, benign bone lesions PET/CT still sets the reference.

Key Points

? PET/MRI and PET/CT are of equal value for the identification of disease-positive patients ? PET/MRI offers higher lesion conspicuity as well as diagnostic confidence ? PET/MRI is an attractive new alternative for the assessment of bone metastases     

Complementary roles of tumour specific PET tracer 18F-FAMT to 18F-FDG PET/CT for the assessment of bone metastasis

Purpose

The usefulness of ¹⁸F-FDG PET/CT for bone metastasis evaluation has already been established. The amino acid PET tracer [¹⁸F]-3-fluoro-alpha-methyl tyrosine (¹⁸F-FAMT) has been reported to be highly specific for malignancy. We evaluated the additional value of ¹⁸F-FAMT PET/CT to complement ¹⁸F-FDG PET/CT in the evaluation of bone metastasis.

Methods

This retrospective study included 21 patients with bone metastases of various cancers who had undergone both ¹⁸F-FDG and ¹⁸F-FAMT PET/CT within 1 month of each other. ¹⁸F-FDG-avid bone lesions suspicious for malignancy were carefully selected based on the cut-off value for malignancy, and the SUVmax of the ¹⁸F-FAMT in the corresponding lesions were evaluated.

Results

A total of 72 ¹⁸F-FDG-positive bone lesions suspected to be metastases in the 21 patients were used as the reference standard. ¹⁸F-FAMT uptake was found in 87.5 % of the lesions. In the lesions of lung cancer origin, the uptake of the two tracers showed a good correlation (40 lesions, r?=?0.68, P?<?0.01). Bone metastatic lesions of oesophageal cancer showed the highest average of ¹⁸F-FAMT uptake. Bone metastatic lesions of squamous cell carcinoma showed higher ¹⁸F-FAMT uptake than those of adenocarcinoma. No significant difference in ¹⁸F-FAMT uptake was seen between osteoblastic and osteolytic bone metastatic lesions.

Conclusion

The usefulness of ¹⁸F-FAMT PET/CT for bone metastasis detection regardless of the lesion phenotype was demonstrated. The fact that ¹⁸F-FAMT uptake was confirmed by ¹⁸F-FDG uptake suggests that ¹⁸F-FAMT PET/CT has the potential to complement ¹⁸F-FDG PET/CT for the detection of bone metastases.     

Comparison of diagnostic ability between 99mTc-MDP bone scan and 18F-FDG PET/CT for bone metastasis in patients with small cell lung cancer

Objective

The aim of this study was to compare the diagnostic ability of ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) with that of ^99mTc-methylene diphosphonate (^99mTc-MDP) bone scan for bone metastasis in staging patients with small cell lung cancer (SCLC).

Methods

Ninety-five patients with SCLC who underwent both ¹⁸F-FDG PET/CT and ^99mTc-MDP bone scan for initial staging work-up were retrospectively enrolled. All ¹⁸F-FDG PET/CT and bone scan images were visually assessed. Bone metastasis was confirmed by histopathological results and all available clinical information.

Results

Of 95 patients with SCLC, metastatic bone lesions were found in 30 patients, and 84 metastatic lesions were evaluated on a lesion-basis analysis. The sensitivity of ¹⁸F-FDG PET/CT was 100?% on a per-patient basis and 87?% on a per-lesion basis, and there was no false-positive lesion on PET/CT images. In contrast, the sensitivity of the bone scan was 37?% on a per-patient basis and 29?% on a per-lesion basis. The bone scan showed 11 false-positive lesions. The bone scan detected two metastatic lesions that were not detected by PET/CT, which were outside the region scanned by PET/CT. On follow-up bone scan, 21 lesions that were not detected by the initial bone scan but were detected by PET/CT were newly detected.

Conclusions

In patients with SCLC, ¹⁸F-FDG PET/CT showed higher detection rate of bone metastasis than ^99mTc-MDP bone scan. Thus, ¹⁸F-FDG PET/CT can replace bone scan in staging patients with SCLC.     

The usefulness of F-18 fluorodeoxyglucose positron emission tomography/computed tomography in patients with Langerhans cell histiocytosis

Objective

Langerhans cell histiocytosis (LCH) has a wide spectrum of clinical manifestations, ranging from spontaneous resolution to rapid progression or death, with the risk of permanent consequences. F-18 FDG PET/CT has been used for assessment of LCH patients. However, its clinical implication has not been well elucidated, mainly due to very low incidence of LCH. The aim of this study was to evaluate the clinical usefulness of F-18 FDG PET/CT in LCH patients.

Methods

A database of 12 patients (mean age 17.8?±?17.9?years; 7 children, 5 adults) who were diagnosed histopathologically as LCH was retrospectively reviewed. Two patients underwent F-18 FDG PET/CT before and after therapy, 6 patients underwent only before therapy and 4 patients underwent only after therapy.

Results

Nine (75.0?%) and 3 patients (25.0?%) had single-system (single site and multiple sites) and multisystem involvements, respectively. Pretreatment SUV_max of patients with multisystem or multiple site involvement of a single-system was significantly higher than that of patients with single site involvement of a single-system (3.29?±?2.52 vs. 1.63?±?0.52, p?=?0.025). One patient showed multisystem risk organs (lung and bone marrow) involvement. In 2 patients, F-18 FDG PET/CT detected additional active LCH lesions not identified on conventional imaging modalities. In follow-up F-18 FDG PET/CT scans, complete resolution was identified in 2 patients and reactivation in another 2 patients.

Conclusions

Results of this study suggest that F-18 FDG PET/CT is useful for identification of active lesions, stratification of disease stages, monitoring of therapeutic response, and detection of reactivation in LCH patients.     

Therapeutic impact of 18F-FDG PET/CT in recurrent differentiated thyroid carcinoma

Purpose

¹⁸F-fluorodeoxyglucose-positron emission tomography/computed tomography (PET/CT) has proved effective in detecting recurrent or metastatic differentiated thyroid carcinoma (DTC) in the follow-up of operated DTC patients with high thyroglobulin (Tg) levels and negative findings on radioiodine whole-body scan. The aim of this retrospective study was to assess the impact of PET/CT on the planning of appropriate treatment for known recurrent disease in operated DTC patients.

Materials and methods

The study concerned 44 consecutive DTC patients (36 papillary, 8 follicular), who underwent total thyroidectomy and thyroid remnant ablation with ¹³¹I and PET/CT. All patients had proven or strongly suspected recurrent disease judging from neck ultrasound (US) and fine-needle aspiration cytology, and detectable basal Tg levels.

Results

PET/CT findings were positive in 25/44 patients (56.81 %) and negative in 19. A positive PET/CT result predicted resectable tumour recurrences in 19/25 patients, but also detected additional tumour sites that prompted changes to the treatment plan in 6/25 patients (24 %). A negative PET/CT result led to clinical monitoring for 11/19 patients (57.89 %).

Conclusions

PET/CT can help select patients, who might benefit from a tailored therapy by improving the detection of local recurrences not apparent on neck US or metastases.