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.     

11C]-choline PET/CT in imaging locally advanced prostate cancer

PET Imaging with [11C]-choline has become a useful tool in the investigation of prostate cancer, with as main application the assessment of previously treated patients presenting with rising PSA and negative conventional imaging procedures. In this case report we describe [11C]-choline PET/CT findings in a patient with a locally advanced cancer, which could be successfully identified thanks to the early image acquisition and the delayed urinary excretion of the carbon-11 labeled tracer.     

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.

     

Investigation on the role of integrated PET/MRI for target volume definition and radiotherapy planning in patients with high grade glioma

Purpose

To evaluate the impact of fluid-attenuated-inversion-recovery MRI (FLAIR/MRI) and Carbon-11-labeled-methionine PET (11C-MET-PET) on high grade glioma (HGG) tumor volume delineation for radiotherapy planning.

Material and methods

Sixty-nine patients with HGG were evaluated. The clinical target volumes (CTV1, generated by adding a 10 mm margin to FLAIRMRI area, CTV2 by adding a 20 mm margin to enhanced T1MRI) and biological target volume (BTV) were delineated on pre-operative MRI images and 11CMETPET respectively.

Results

The overlap between CTV1 and CTV2 showed a low correlation between the two volumes with CTV1 not always fully included into the CTV2. In all cases the whole BTV was included into the CTV1, while in 35/69 patients (50%) part of BTV was outside the CTV2 despite larger margins were added. In all cases recurrences were within the CTV1 volume and in 19/38 (50%) partially outside the CTV2. In all patients relapse corresponded to the BTV area.

Conclusions

Our data suggest that the target volume definition using FLAIR–MRI is more adequate compared to enhanced T1MRI. 11C-METPET uptake could help identify microscopic residual areas.     

Molecular imaging and targeted therapies in oncology: new concepts in treatment response assessment. a collection of cases

The widespread use of several new non-cytotoxic drugs and the significant improvements in functional imaging highlights a number of difficulties in monitoring, interpreting and predicting treatment response in clinical practice. Certain guidelines for disease assessment after therapy are already available: the traditional Response Evaluation Criteria in Solid Tumours guidelines based on tumour size variations using conventional imaging technologies, the recent combined method developed by Choi and colleagues in gastrointestinal stromal tumour treated with tyrosine kinase inhibitors based on tumour density variations using computed tomography (CT), and the European Organization for Research and Treatment of Cancer criteria based on tumour glucose metabolism variations using fluorodeoxyglucose (FDG) positron emission tomography (PET). At the moment combined PET/CT response criteria are still not available. A number of new PET compounds other than FDG are also currently being developed to visualize specific cellular and molecular tumour pathways but their role in assessment and prediction of cancer treatment response has not yet been thoroughly investigated in a large series. However, in clinical practice many oncologists treat cancer patients with targeted therapies or chemotherapy and evaluate the response using conventional or functional imaging without appropriate and standardized guidelines. The aim of this study was to present a selection of clinical cases that illustrate the usefulness of new PET tracers and efficacy evaluation of new drugs. In the era of molecular imaging and molecular therapies, these cases highlight the urgency to develop new criteria for treatment assessment and the exigency of correctly interpreting the biological information obtained from new technologies, and introduce new concepts that require further investigation in clinical trials.     

Metabolic Switch in Hepatocellular Carcinoma Patients Treated with Sorafenib: a Proof-of-Concept Trial

Molecular Imaging and Biology - Sorafenib is a multikinase inhibitor used to treat advanced hepatocellular carcinoma (HCC). Recently, a preclinical trial has shown that response to sorafenib is...