¹²³I-MIBG scintigraphy/SPECT versus ¹⁸F-FDG PET in paediatric neuroblastoma

Diagnostic value of 18F-fluorodeoxyglucose positron emission tomography/computed tomography imaging in pediatric opsoclonus myoclonus ataxia syndrome presenting with neuroblastoma

BACKGROUND

Early precision diagnosis and effective treatment of opsoclonus myoclonus ataxia syndrome (OMAS) patients presenting with neuroblastoma can prevent serious neurological outcomes.

OBJECTIVE

To assess the diagnostic value of 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) imaging in pediatric OMAS with neuroblastoma.

MATERIALS AND METHODS

A retrospective evaluation of 45 patients diagnosed with OMAS who underwent 18F-FDG PET/CT was performed. A univariate analysis was performed to compare clinical characteristics between OMAS with and without neuroblastoma. Univariate and multivariate logistic regression analyses were applied to identify independent risk factors for OMAS with neuroblastoma and to develop the clinical model. Finally, independent risk factors and PET/CT were fitted to build the combined model for the diagnosis of OMAS with neuroblastoma and presented as a nomogram. Receiver operating characteristic curve, decision curve, and calibration curve analyses were conducted to evaluate the performance of the models.

RESULTS

Among 45 patients, 27 were PET/CT-positive, 23/27 lesions were neuroblastoma, and four were false positives. One of the false positive patients was confirmed to be adrenal reactive hyperplasia by postoperative pathology, and the symptoms of OMAS disappeared in the remaining three cases during clinical follow-up. The average maximal standardized uptake value of PET/CT-positive lesions was 2.6. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of PET/CT were 100%, 81.8%, 85.2%, 100%, and 91.1%, respectively. Age at diagnosis, lactate dehydrogenase, and neuron-specific enolase showed statistically significant differences between OMAS with and without neuroblastoma. Lactate dehydrogenase was identified as the independent risk factor to develop the clinical model, and the clinical model demonstrated an area under the curve (AUC) of 0.82 for the diagnosis of OMAS with neuroblastoma, with an AUC as high as 0.91 when combined with PET/CT. The decision curve analysis and calibration curve demonstrated that the nomogram had good consistency and clinical usefulness.

CONCLUSION

In patients with OMAS, 18F-FDG PET/CT has a high diagnostic accuracy in detecting tumors of the neuroblastoma, especially when combined with the independent risk factor serum lactate dehydrogenase.

Predictive value of 18 F-FDG PET/CT versus bone marrow biopsy and aspiration in pediatric neuroblastoma

BACKGROUND

Neuroblastoma (NB) is the most prevalent solid extracranial malignancy in children, often with bone marrow metastases (BMM) are present. The conventional approach for detecting BMM is bone marrow biopsy and aspiration (BMBA). 18 F-fluorodeoxyglucose-positron emission tomography/computed tomography (18 F-FDG PET/CT) has become a staple for staging and is also capable of evaluating marrow infiltration. The consensus on the utility of 18 F-FDG PET/CT for assessing BMM in NB patients is still under deliberation.

METHODS

This retrospective study enrolled 266 pediatric patients with pathologically proven NB. All patients had pretherapy FDG PET/CT. BMBA, clinical, radiological, and follow-up data were also collected. The diagnostic accuracy of BMBA and 18 F-FDG PET/CT was assessed.

RESULTS

BMBAs identified BMM in 96 cases (36.1%), while 18 F-FDG PET/CT detected BMI in 106 cases (39.8%) within the cohort. The initial sensitivity, positive predictive value (PPV), specificity, and negative predictive value (NPV) of 18 F-FDG PET/CT were 93.8%, 84.9%, 90.6%, and 96.3%, respectively. After treatment, these values were 92.3%, 70.6%, 97.3%, and 99.4%, respectively. The kappa statistic, which measures agreement between BMBA and 18 F-FDG PET/CT, was 0.825 before treatment and 0.784 after treatment, with both values indicating a substantial agreement (P = 0.000). Additionally, the amplification of MYCN and a positive initial PET/CT scan were identified as independent prognostic factors for overall survival (OS).

CONCLUSION

18 F-FDG-PET/CT is a valuable method for evaluating BMM in NB. The routine practice of performing a BMBA without discrimination may need to be reassessed. Negative result from 18 F-FDG-PET/CT could potentially spare children with invasive bone marrow biopsies.

Prognostic Value of Metabolic Parameters and Textural Features in Pretreatment 18F-FDG PET/CT of Primary Lesions for Pediatric Patients with Neuroblastoma

RATIONALE AND OBJECTIVES

Our study evaluated the prognostic value of the metabolic parameters and textural features in pretreatment 18F-Fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) of primary lesions for pediatric patients with neuroblastoma.

MATERIALS AND METHODS

In total, 107 pediatric patients with neuroblastoma who underwent pretreatment 18F-FDG PET/CT were retrospectively included and analyzed. All patients were diagnosed by pathology, and baseline characteristics and clinical data were collected. The four metabolic parameters and 43 textural features of 18F-FDG PET/CT of the primary lesions were measured. The prognostic significance of metabolic parameters and other clinical variables was assessed using Cox proportional hazards regression models. Differences in progression-free survival (PFS) and overall survival (OS) in relation to parameters were examined using the Kaplan-Meier method.

RESULTS

During a median follow-up period of 34.3 months, 45 patients (42.1%) experienced tumor recurrence or progression, and 21 patients (19.6%) died of cancer. In univariate Cox regression analysis, age, location of disease, International Neuroblastoma Risk Group Staging System (INRGSS) stage M, neuron-specific enolase (NSE), lactate dehydrogenase (LDH), four positron emission tomography (PET) metabolic parameters, and 33 textural features were significant predictors of PFS. In multivariate analysis, INRGSS stage M (hazard ratio [HR] = 19.940, 95% confidence interval [CI] = 2.733-145.491, P = 0.003), skewness (＞0.173; PET first-order features; HR = 2.938, 95% CI = 1.389-6.215, P = 0.005), coarseness (＞0.003; neighborhood gray-tone difference matrix; HR = 0.253, 95% CI = 0.132-0.484, P ＜ 0.001), and variance (＞103.837; CT first-order gray histogram parameters; HR = 2.810, 95% CI = 1.160-6.807, P = 0.022) were independent predictors of PFS. In univariate Cox regression analysis, gender, INRGSS stage M, MYCN amplification, NSE, LDH, two PET metabolic parameters, and five textural features were significant predictors of OS. In multivariate analysis, INRGSS stage M (HR = 7.704, 95% CI = 1.031-57.576, P = 0.047), MYCN amplification (HR = 3.011, 95% CI = 1.164-7.786, P = 0.023), and metabolic tumor volume (＞138.788; HR = 3.930, 95% CI = 1.317-11.727, P = 0.014) were independent predictors of OS.

CONCLUSION

The metabolic parameters and textural features in pretreatment 18F-FDG PET/CT of primary lesions are predictive of survival in pediatric patients with neuroblastoma.

18F-FDG PET/CT-Based Radiomics Nomogram for Prediction of Bone Marrow Involvement in Pediatric Neuroblastoma: A Two-Center Study

RATIONALE AND OBJECTIVES

To assess the predictive ability of an 18F-FDG PET/CT-based radiomics nomogram for bone marrow involvement in pediatric neuroblastoma.

MATERIALS AND METHODS

A total of 241 neuroblastoma patients who underwent 18F-FDG PET/CT at two medical centers were retrospectively evaluated. Data from center A (n = 200) were randomized into a training cohort (n = 140) and an internal validation cohort (n = 60), while data from center B (n = 41) constituted the external validation cohort. For each patient, two regions of interest were defined using the tumor and axial skeleton. The clinical factors and radiomics features were derived to construct the clinical and radiomics models. The radiomics nomogram was built by combining clinical factors and radiomics features. The area under the receiver operating characteristic curves (AUCs) were used to assess the performance of the models.

RESULTS

Radiomics models created from tumor and axial skeleton achieved AUCs of 0.773 and 0.900, and the clinical model had an AUC of 0.858 in the training cohort. By incorporating clinical risk factors and axial skeleton-based radiomics features, the AUC of the radiomics nomogram in the training cohort, internal validation cohort, and external validation cohort was 0.932, 0.887, and 0.733, respectively.

CONCLUSION

The axial skeleton-based radiomics model performed better than the tumor-based radiomics model in predicting bone marrow involvement. Moreover, the radiomics nomogram showed that combining axial skeleton-based radiomics features with clinical risk factors improved their performance.

Clinical approach to diagnosis of paraneoplastic neurologic syndromes

The correct diagnosis of a paraneoplastic neurologic syndrome (PNS) first requires the identification of the syndrome as one of those defined as high-risk (previously called classical) or intermediate-risk for cancer in the 2021 PNS diagnostic criteria. Testing for neuronal antibodies should be restricted to these syndromes as indiscriminate request decreases the diagnostic value of the antibodies. Identifying onconeural (high-risk for cancer) or intermediate-risk for cancer antibodies supports the paraneoplastic diagnosis and mandates the search for an underlying cancer. Tumor screening must follow the published guidelines. Repeated screening is indicated in neurologic syndromes with onconeural antibodies and patients with high-risk for cancer neurologic syndromes unless they present neuronal antibodies which are not associated with cancer. Neuronal antibodies should be screened by immunohistochemistry and confirmed by immunoblot (intracellular antigens) or cell-based assay (CBA) (surface antigens). Positive results only by immunoblot or CBA should be taken with caution. Although the 2021 diagnostic criteria for PNS do not capture all PNS, as they do not allow to diagnose definite PNS neurologic syndromes without neuronal antibodies, the updated criteria represent a step forward to differentiate true PNS from neurologic syndromes that coincide in time with cancer diagnosis without having a pathogenic link.

Current Status and Future Perspective on Molecular Imaging and Treatment of Neuroblastoma

Neuroblastoma is the most common extracranial solid tumor in children and arises from anywhere along the sympathetic nervous system. It is a highly heterogeneous disease with a wide range of prognosis, from spontaneous regression or maturing to highly aggressive. About half of pediatric neuroblastoma patients develop the metastatic disease at diagnosis, which carries a poor prognosis. Nuclear medicine plays a pivotal role in the diagnosis, staging, response assessment, and long-term follow-up of neuroblastoma. And it has also played a prominent role in the treatment of neuroblastoma. Because the structure of metaiodobenzylguanidine (MIBG) is similar to that of norepinephrine, 90% of neuroblastomas are MIBG-avid. 123I-MIBG whole-body scintigraphy is the standard nuclear imaging technique for neuroblastoma, usually in combination with SPECT/CT. However, approximately 10% of neuroblastomas are MIBG nonavid. PET imaging has many technical advantages over SPECT imaging, such as higher spatial and temporal resolution, higher sensitivity, superior quantitative capability, and whole-body tomographic imaging. In recent years, various tracers have been used for imaging neuroblastoma with PET. The importance of patient-specific targeted radionuclide therapy for neuroblastoma therapy has also increased. 131I-MIBG therapy is part of the front-line treatment for children with high-risk neuroblastoma. And peptide receptor radionuclide therapy with radionuclide-labeled somatostatin analogues has been successfully used in the therapy of neuroblastoma. Moreover, radioimmunoimaging has important applications in the diagnosis of neuroblastoma, and radioimmunotherapy may provide a novel treatment modality against neuroblastoma. This review discusses the use of current and novel radiopharmaceuticals in nuclear medicine imaging and therapy of neuroblastoma.

Durchführung und Befundung der 123I-mIBG-Szintigraphie bei Kindern und Jugendlichen mit Neuroblastom (Version 3) – DGN-Handlungsempfehlung (S1-Leitlinie), Stand: 2/2020 – AWMF-Registernummer: 031-040

Die aktualisierte 3. Fassung der 123I-mIBG-Szintigrafie bei Kindern und Jugendlichen berücksichtigt folgende aktuelle Entwicklungen: Die Leitlinie fokussiert auf die diagnostische Anwendung von 123I-mIBG beim Neuroblastom. 131I-mIBG kommt bei der Radionuklidtherapie zum Einsatz. An wenigen Stellen wird auf Besonderheiten des 131I-mIBG bei der Befundung von Posttherapie-Szintigrammen eingegangen. Es werden aktuelle Entwicklungen in der Patientenvorbereitung bei den Medikamenteninterferenzen und Empfehlungen zur Schilddrüsenblockade berücksichtigt. Neue Empfehlungen der zu applizierenden Aktivität werden genannt und die damit assoziierten Probleme diskutiert. Die Bildakquisition unter Berücksichtigung von SPECT bzw. SPECT/CT des Körperstammes inkl. des Kopfes wird berücksichtigt. Die Befundung unter Verwendung des SIOPEN-Scores wird neu aufgenommen. Auf PET bzw. PET/CT mit 18F-DOPA bzw. 68Ga-DotaTATE wird verwiesen.

Prediction of MYCN Amplification, 1p and 11q Aberrations in Pediatric Neuroblastoma via Pre-therapy 18F-FDG PET/CT Radiomics

Purpose

This study aimed to assess the predictive ability of 18F-FDG PET/CT radiomic features for MYCN, 1p and 11q abnormalities in NB.

Method

One hundred and twenty-two pediatric patients (median age 3. 2 years, range, 0.2–9.8 years) with NB were retrospectively enrolled. Significant features by multivariable logistic regression were retained to establish a clinical model (C_model), which included clinical characteristics. 18F-FDG PET/CT radiomic features were extracted by Computational Environment for Radiological Research. The least absolute shrinkage and selection operator (LASSO) regression was used to select radiomic features and build models (R-model). The predictive performance of models constructed by clinical characteristic (C_model), radiomic signature (R_model), and their combinations (CR_model) were compared using receiver operating curves (ROCs). Nomograms based on the radiomic score (rad-score) and clinical parameters were developed.

Results

The patients were classified into a training set (n = 86) and a test set (n = 36). Accordingly, 6, 8, and 7 radiomic features were selected to establish R_models for predicting MYCN, 1p and 11q status. The R_models showed a strong power for identifying these aberrations, with area under ROC curves (AUCs) of 0.96, 0.89, and 0.89 in the training set and 0.92, 0.85, and 0.84 in the test set. When combining clinical characteristics and radiomic signature, the AUCs increased to 0.98, 0.91, and 0.93 in the training set and 0.96, 0.88, and 0.89 in the test set. The CR_models had the greatest performance for MYCN, 1p and 11q predictions (P < 0.05).

Conclusions

The pre-therapy 18F-FDG PET/CT radiomics is able to predict MYCN amplification and 1p and 11 aberrations in pediatric NB, thus aiding tumor stage, risk stratification and disease management in the clinical practice.

Diagnostic Value of Seven Different Imaging Modalities for Patients with Neuroblastic Tumors: A Network Meta-Analysis

Objective

We performed a systematic review and network meta-analysis (NMA) to compare the diagnostic value of seven different imaging modalities for the detection of neuroblastic tumors in diverse clinical settings.

Methods

PubMed, Embase, Medline, and the Cochrane Library were searched to identify eligible studies from inception to Sep 29, 2020. Quality assessment of included studies was appraised with Quality Assessment of Diagnostic Accuracy Studies. Firstly, direct pairwise meta-analysis was conducted to calculate the pooled estimates of odds ratio (OR) and 95% confidence interval (CI) of the sensitivity, specificity, NPV, PPV, and DR. Next, NMA using Bayesian methods was performed. The superiority index was assessed to quantify the rank probability of a diagnostic test. The studies performed SPECT/CT or SPECT were analyzed separately from the ones only performed planar imaging.

Results

A total of 1135 patients from 32 studies, including 7 different imaging modalities, were eligible for this NMA. In the pairwise meta-analysis, ¹⁸F-FDOPA PET/CT had a relatively high value of all the outcomes (sensitivity: 10.195 [5.332–19.493]; specificity: 17.906 [5.950–53.884]; NPV: 16.819 [7.033–40.218]; PPV: 11.154 [4.216–29.512]; and DR 5.616 [3.609–8.739]). In the NMA, ¹⁸F-FDOPA PET/CT exhibited relatively high sensitivity in all subgroups (all data: 0.94 [0.87–0.98]; primary tumor: 0.89 [0.53–1]; bone/bone marrow metastases: 0.96 [0.83–1]; and primary tumor and metastases (P + M): 0.92 [0.80–0.97]), the highest specificity in the subgroup of P + M (0.85 [0.61–0.97]), and achieved the highest superiority index in the subgroups of all data (8.57 [1–15]) and P + M (7.25 [1–13]).

Conclusion

¹⁸F-FDOPA PET/CT exhibited the best diagnostic performance in the comprehensive detection of primary tumor and metastases for neuroblastic tumors, followed by ⁶⁸Ga-somatostatin analogs, ¹²³I-meta-iodobenzylguanidine (MIBG), ¹⁸F-FDG, and ¹³¹I-MIBG tomographic imaging.

Does the Incremental Value of 123I-Metaiodobenzylguanidine SPECT/CT over Planar Imaging Justify the Increase in Radiation Exposure?

Purpose

Planar scintigraphy with ¹²³I-radiolabeled metaiodobenzylguanidine (¹²³I-mIBG) is an important imaging modality to evaluate neuroblastoma. In recent years, Single Photon Emission Computed Tomography combined with Computed Tomography (SPECT/CT) has revolutionized nuclear medicine. Nevertheless, the addition of the CT has increased the patients' irradiation. We aimed to evaluate the incremental benefits of ¹²³I-mIBG SPECT/CT over conventional planar imaging and to estimate the relative increase of radiation dose.

Methods

We retrospectively evaluated the added value of 56 SPECT/CT performed in 40 children in terms of better characterization of the lesion and its locoregional extension, better lymph node staging, detection of new lesions, and elimination of false positives by a paired comparison between the planar images and the SPECT/CT ones. Then, we calculated the percentage contribution of the additional radiation of the CT in this hybrid imagery.

Results

In 88% (49 out of 56) of the examinations, SPECT/CT provided additional information, which was crucial in 20% of the cases. It allowed a better characterization of the lesion and its locoregional extension in 44 cases, a better lymph node staging in 28 cases, the detection of 33 new lesions, and the elimination of 9 false positives. The CT effective dose was significantly lower than the SPECT one. The average additional radiation exposure due to CT was 12% (4-23%).

Conclusion

¹²³I-mIBG SPECT/CT has an undeniable added value that improves planar imaging interpretation and impacts patient management. These potential benefits would justify the low additional radiation induced by the CT.

Extremely low 18F-fluorodeoxyglucose uptake in the brain of a patient with metastatic neuroblastoma and its recovery after chemotherapy: A case report

Commonly, physiological ¹⁸F-fluorodeoxyglucose (FDG) uptake in the brain can be observed in ¹⁸F-FDG positron emission tomography. Abnormal uptake of ¹⁸F-FDG in the brain suggests disorders of central nervous system. Here, we present a case of extremely low ¹⁸F-FDG uptake in the brain of a 4-year-old girl with whole-body metastatic neuroblastoma. Almost missing of physiological ¹⁸F-FDG uptake in the brain was ascribed at least partly to the metastatic neuroblastoma. The brain could regain physiological ¹⁸F-FDG uptake after chemotherapy.

Diagnostic Performance of 18F-FDG PET(CT) in Bone-Bone Marrow Involvement in Pediatric Neuroblastoma: A Systemic Review and Meta-Analysis

Objective

We sought to perform a systemic review and meta-analysis of the diagnostic performance of ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (computed tomography) (PET(CT)) in detection of bone and/or bone marrow involvement (BMI) in pediatric neuroblastoma (NB).

Materials and Methods

We searched electronic databases Pubmed and Embase to retrieve relevant references. We calculated pooled sensitivity, specificity, positive and negative likelihood ratios (LR+ and LR−), diagnostic odds ratio (DOR), and the area under the curve (AUC). Moreover, a summary receiver operating characteristic (SROC) curve and likelihood ratio dot plot were plotted. Study-between statistical heterogeneity was evaluated via I-square index (I²). Subgroup analyses were used to explore heterogeneity.

Results

Seven studies including 127 patients were involved in this meta-analysis. The overall sensitivity and specificity were 0.87 (95% CI: 0.65–0.96) with heterogeneity I² = 88.1% (p < 0.001) and 0.96 (95% CI: 0.67–1.00) with heterogeneity I² = 77.8% (p < 0.001), respectively. The pooled LR+, LR−, and DOR were 21.3 (95% CI: 2.1–213.9), 0.14 (95% CI: 0.05–0.40), and 157 (95% CI: 16–1532), respectively. The area under the SROC curve was 0.97 (95% CI: 0.95–0.98).

Conclusions

Through a meta-analysis, this study suggested that ¹⁸F-FDG PET(CT) has a good overall diagnostic accuracy in the detection of bone/BMI in pediatric neuroblastoma.

Theranostics in Neuroblastoma

Theranostics combines diagnosis and targeted therapy, achieved by the use of the same or similar molecules labeled with different radiopharmaceuticals or identical with different dosages. One of the best examples is the use of metaiodobenzylguanidine (MIBG). In the management of neuroblastoma-the most common extracranial solid tumor in children. MIBG has utility not only for diagnosis, risk-stratification, and response monitoring but also for cancer therapy, particularly in the setting of relapsed/refractory disease. Improved techniques and new emerging radiopharmaceuticals likely will strengthen the role of nuclear medicine in the management of neuroblastoma.

Nuclear Medicine Imaging in Neuroblastoma: Current Status and New Developments

Neuroblastoma is the most common extracranial solid malignancy in children. At diagnosis, approximately 50% of patients present with metastatic disease. These patients are at high risk for refractory or recurrent disease, which conveys a very poor prognosis. During the past decades, nuclear medicine has been essential for the staging and response assessment of neuroblastoma. Currently, the standard nuclear imaging technique is meta-[¹²³I]iodobenzylguanidine ([¹²³I]mIBG) whole-body scintigraphy, usually combined with single-photon emission computed tomography with computed tomography (SPECT-CT). Nevertheless, 10% of neuroblastomas are mIBG non-avid and [¹²³I]mIBG imaging has relatively low spatial resolution, resulting in limited sensitivity for smaller lesions. More accurate methods to assess full disease extent are needed in order to optimize treatment strategies. Advances in nuclear medicine have led to the introduction of radiotracers compatible for positron emission tomography (PET) imaging in neuroblastoma, such as [¹²⁴I]mIBG, [¹⁸F]mFBG, [¹⁸F]FDG, [⁶⁸Ga]Ga-DOTA peptides, [¹⁸F]F-DOPA, and [¹¹C]mHED. PET has multiple advantages over SPECT, including a superior resolution and whole-body tomographic range. This article reviews the use, characteristics, diagnostic accuracy, advantages, and limitations of current and new tracers for nuclear medicine imaging in neuroblastoma.

Diagnostic values of 68Ga-labelled DOTANOC PET/CT imaging in pediatric patients presenting with paraneoplastic opsoclonus myoclonus ataxia syndrome

OBJECTIVES

Opsoclonus myoclonus ataxia (OMA) syndrome, also known as "Kinsbourne syndrome" or "dancing eye syndrome," is a rare, paraneoplastic entity which may be associated with pediatric neuroblastic tumors and carry a grave prognosis. We aimed to evaluate the role of ⁶⁸Ga DOTANOC PET/CT for detecting neuroblastic tumors in patients with OMA syndrome.

METHODS

We retrospectively evaluated the ⁶⁸Ga-DOTANOC PET/CT data of pediatric patients presenting with OMA syndrome from March 2012 to November 2018. A somatostatin receptor (SSTR)-expressing lesion with corresponding morphological change on CT image was considered PET-positive, while no abnormal SSTR expression or lesion was noticed in PET-negative patients. Histopathology and/or clinical/imaging follow-up (minimum one year) was considered a reference standard for comparing the PET/CT findings. The results of ⁶⁸Ga-DOTANOC PET/CT were also compared with ¹³¹I MIBG whole-body scintigraphy, which was available in five patients.

RESULTS

Of 38 patients (13 males, 25 females, aged 3-96 months), 18 (47.3%) had SSTR-expressing lesions (PET-positive), and histopathology revealed neuroblastic tumors in 17/18 lesions (neuroblastoma 14, ganglioneuroblastoma 2, and ganglioneuroma 1) and reactive hyperplasia in 1/18. The remaining 20/38 (52.6%) patients did not demonstrate SSTR-expressing lesions (PET-negative) and had an uneventful follow-up. The average SUVmax of the PET-positive lesions was 10.3 (range 2.8-34.5). The PET/CT results revealed 17 true-positive, one false-positive, 20 true-negative, and zero false-negative. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 100%, 95.2%, 94.4%, 100%, and 97.3% respectively.

CONCLUSIONS

⁶⁸Ga-DOTANOC PET/CT identified neuroblastic tumors with a high diagnostic accuracy in our cohort compared to histology and follow-up.

KEY POINTS

• Opsoclonus myoclonus ataxia (OMA) syndrome or "dancing eye syndrome" is a rare paraneoplastic entity which may be associated with pediatric neuroblastic tumors with a grave prognosis. • ¹²³I/¹³¹I MIBG imaging has a proven role for functional imaging in neuroblastoma or patients with OMA, but the role of ⁶⁸Ga-DOTANOC PET/CT is not yet studied. • 68Ga-labelled DOTANOC PET/CT (SSTR) imaging, in our cohort, was able to positively identify neuroblastic tumors with high diagnostic accuracy when compared with histology.

Association between end-induction response according to the revised International Neuroblastoma Response Criteria (INRC) and outcome in high-risk neuroblastoma patients

BACKGROUND

The 1993 International Neuroblastoma Response Criteria (INRC) were revised in 2017 to include modern functional imaging studies and methods for quantifying disease in bone marrow. We hypothesized the 2017 INRC would enable more precise assessment of response to treatment and provide superior prognostic information compared with the 1993 criteria.

METHODS

High-risk (HR) neuroblastoma patients from two institutions in Chicago diagnosed between 2006 and 2016 were identified. Patients were assessed post induction chemotherapy via the 1993 and 2017 INRC and classified as responder (≥ mixed response [MXR] or ≥ minor response [MR], respectively) or nonresponder (< MXR or < MR). Event-free survival (EFS) and overall survival (OS) for responders versus nonresponders were determined from end induction and stratified by Cox regression. Patients with progressive disease at end induction were eliminated from the EFS analyses but included in the OS analysis.

RESULTS

The 1993 criteria classified 52 of the 60 HR patients as responders, whereas 54 responders were identified using the 2017 criteria (Spearman correlation r = 0.82, P < 0.001). No statistically significant difference in EFS was observed for responders versus nonresponders using either criteria (P = 0.48 and P = 0.08). However, superior OS was observed for responders (P = 0.01) using either criteria. Both criteria were sensitive in identifying responders among those with good outcomes. The specificity to identify nonresponders among those with poor outcomes was poor.

CONCLUSIONS

In HR neuroblastoma, end-induction response defined by the 1993 or 2017 INRC is associated with survival. Larger cohorts are needed to determine if the 2017 INRC provides more precise prognostication.

Roles of PET/Computed Tomography in the Evaluation of Neuroblastoma

Neuroblastoma is one of the most common pediatric malignant tumors. Functional imaging plays an important role in the diagnosis, staging, and therapy response monitoring of neuroblastoma. Although metaiodobenzylguanidine scan with single-photon emission computed tomography/computed tomography remains the mainstay in functional imaging of the neuroblastomas, PET/CT has begun to show increased utility in this clinical setting.

The Diagnostic Accuracy of PET(CT) in Patients With Neuroblastoma: A Meta-Analysis and Systematic Review

OBJECTIVE

The objective of this study was to evaluate the overall diagnostic value of PET(CT) in patients with neuroblastoma (NB) based on qualified studies.

METHODS

PubMed, Cochrane, and Embase database were searched by the index words to identify the qualified studies, and relevant literature sources were also searched. The latest research was performed in April 2019. Heterogeneity of the included studies was tested, which was used to select proper effect model to calculate pooled weighted sensitivity, specificity, and diagnostic odds ratio (DOR). Summary receiver operating characteristic (SROC) analyses were also performed.

RESULTS

Eleven studies with 580 patients were involved in the meta-analysis to explore the diagnostic accuracy of PET(CT) for NB. PET(CT) has high diagnostic accuracy of NB: the global sensitivity was 91% (95% confidence interval [CI], 86%-94%), the global specificity was 78% (95% CI, 66%-86%), the global positive likelihood ratio was 4.07 (95% CI, 2.54-6.50), the global negative likelihood ratio was 0.12 (95% CI, 0.08-0.18), the global DOR was 27.43 (95% CI, 14.45-52.07), and the area under the SROC was high (area under the curve, 0.93; 95% CI, 0.90-0.95). Besides this, PET(CT) has high diagnostic accuracy of primary NB: the global sensitivity was 86% (95% CI, 73%-93%), the global specificity was 82% (95% CI, 57%-94%), the global positive likelihood ratio was 4.90 (95% CI, 1.63-14.72), the global negative likelihood ratio was 0.17 (95% CI, 0.07-0.40), the global DOR was 25.427 (95% CI, 3.988-162.098), and the area under the SROC was high (area under the curve, 0.91; 95% CI, 0.88-0.93). However, there has no significant accuracy of PET(CT) in NB with bone marrow.

CONCLUSIONS

This study provides a systematic review and meta-analysis of diagnostic accuracy studies of PET(CT) for NB. The results indicated that PET(CT) is a highly accurate diagnostic tool for NB.

Guidelines on nuclear medicine imaging in neuroblastoma

Nuclear medicine has a central role in the diagnosis, staging, response assessment and long-term follow-up of neuroblastoma, the most common solid extracranial tumour in children. These EANM guidelines include updated information on ¹²³I-mIBG, the most common study in nuclear medicine for the evaluation of neuroblastoma, and on PET/CT imaging with ¹⁸F-FDG, ¹⁸F-DOPA and ⁶⁸Ga-DOTA peptides. These PET/CT studies are increasingly employed in clinical practice. Indications, advantages and limitations are presented along with recommendations on study protocols, interpretation of findings and reporting results.

Diagnostic performance of 18F-FDG PET/CT and whole-body diffusion-weighted imaging with background body suppression (DWIBS) in detection of lymph node and bone metastases from pediatric neuroblastoma

OBJECTIVE

Recent many studies have shown that whole body "diffusion-weighted imaging with background body signal suppression" (DWIBS) seems a beneficial tool having higher tumor detection sensitivity without ionizing radiation exposure for pediatric tumors. In this study, we evaluated the diagnostic performance of whole body DWIBS and ¹⁸F-FDG PET/CT for detecting lymph node and bone metastases in pediatric patients with neuroblastoma.

METHODS

Subjects in this retrospective study comprised 13 consecutive pediatric patients with neuroblastoma (7 males, 6 females; mean age, 2.9 ± 2.0 years old) who underwent both ¹⁸F-FDG PET/CT and whole-body DWIBS. All patients were diagnosed as neuroblastoma on the basis of pathological findings. Eight regions of lymph nodes and 17 segments of skeletons in all patients were evaluated. The images of ¹²³I-MIBG scintigraphy/SPECT-CT, bone scintigraphy/SPECT, and CT were used to confirm the presence of lymph node and bone metastases. Two radiologists trained in nuclear medicine evaluated independently the uptake of lesions in ¹⁸F-FDG PET/CT and the signal-intensity of lesions in whole-body DWIBS visually. Interobserver difference was overcome through discussion to reach a consensus. The sensitivities, specificities, and overall accuracies of ¹⁸F-FDG PET/CT and whole-body DWIBS were compared using McNemer's test. Positive predictive values (PPVs) and negative predictive values (NPVs) of both modalities were compared using Fisher's exact test.

RESULTS

The total numbers of lymph node regions and bone segments which were confirmed to have metastasis in the total 13 patients were 19 and 75, respectively. The sensitivity, specificity, overall accuracy, PPV, and NPV of ¹⁸F-FDG PET/CT for detecting lymph node metastasis from pediatric neuroblastoma were 100, 98.7, 98.9, 95.0, and 100%, respectively, and those for detecting bone metastasis were 90.7, 73.1, 80.3, 70.1, and 91.9%, respectively. In contrast, the sensitivity, specificity, overall accuracy, PPV, and NPV of whole-body DWIBS for detecting bone metastasis from pediatric neuroblastoma were 94.7, 24.0, 53.0, 46.4 and 86.7%, respectively, whereas those for detecting lymph node metastasis were 94.7, 85.3, 87.2, 62.1, and 98.5%, respectively. The low specificity, overall accuracy, and PPV of whole-body DWIBS for detecting bone metastasis were due to a high incidence of false-positive findings (82/108, 75.9%). The specificity, overall accuracy, and PPV of whole-body DWIBS for detecting lymph node metastasis were also significantly lower than those of ¹⁸F-FDG PET/CT for detecting lymph node metastasis, although the difference between these 2 modalities was less than that for detecting bone metastasis.

CONCLUSION

The specificity, overall accuracy, and PPV of whole-body DWIBS are significantly lower than those of ¹⁸F-FDG PET/CT because of a high incidence of false-positive findings particularly for detecting bone metastasis, whereas whole-body DWIBS shows a similar level of sensitivities for detecting lymph node and bone metastases to those of ¹⁸F-FDG PET/CT. DWIBS should be carefully used for cancer staging in children because of its high incidence of false-positive findings in skeletons.

[Simultaneous whole-body PET-MRI in pediatric oncology : More than just reducing radiation?]

Diagnostic imaging plays an essential role in pediatric oncology with regard to diagnosis, therapy-planning, and the follow-up of solid tumors. The current imaging standard in pediatric oncology includes a variety of radiological and nuclear medicine imaging modalities depending on the specific tumor entity. The introduction of combined simultaneous positron emission tomography (PET) and magnetic resonance imaging (MRI) has opened up new diagnostic options in pediatric oncology. This novel modality combines the excellent anatomical accuracy of MRI with the metabolic information of PET. In initial clinical studies, the technical feasibility and possible diagnostic advantages of combined PET-MRI have been in comparison with alternative imaging techniques. It was shown that a reduction in radiation exposure of up to 70 % is achievable compared with PET-CT. Furthermore, it has been shown that the number of imaging studies necessary can be markedly reduced using combined PET-MRI. Owing to its limited availability, combined PET-MRI is currently not used as a routine procedure. However, this new modality has the potential to become the imaging reference standard in pediatric oncology in the future. This review article summarizes the central aspects of pediatric oncological PET-MRI based on existing literature. Typical pediatric oncological PET-MRI cases are also presented.

Comparison of diagnosing and staging accuracy of PET (CT) and MIBG on patients with neuroblastoma: Systemic review and meta-analysis

To perform a systemic review and meta-analysis of the diagnostic accuracy of PET (CT) and metaiodobenzylguanidine (MIBG) for diagnosing neuroblastoma (NB), electronic databases were searched as well as relevant references and conference proceedings. The diagnostic accuracy of MIBG and PET (CT) was calculated for NB, primary NB, and relapse/metastasis of NB based on their sensitivity, specificity, and area under the summary receiver operating characteristic curve (AUSROC) in terms of per-lesion and per-patient data. A total of 40 eligible studies comprising 1134 patients with 939 NB lesions were considered for the meta-analysis. For the staging of NB, the per-lesion AUSROC value of MIBG was lower than that of PET (CT) [0.8064±0.0414 vs. 0.9366±0.0166 (P<0.05)]. The per-patient AUSROC value of MIBG and PET (CT) for the diagnosis of NB was 0.8771±0.0230 and 0.6851±0.2111, respectively. The summary sensitivity for MIBG and PET (CT) was 0.79 and 0.89, respectively. The summary specificity for MIBG and PET (CT) was 0.84 and 0.71, respectively. PET (CT) showed higher per-lesion accuracy than MIBG and might be the preferred modality for the staging of NB. On the other hand, MIBG has a comparable diagnosing performance with PET (CT) in per-patient analysis but shows a better specificity.

Revisions to the International Neuroblastoma Response Criteria: A Consensus Statement From the National Cancer Institute Clinical Trials Planning Meeting

Purpose More than two decades ago, an international working group established the International Neuroblastoma Response Criteria (INRC) to assess treatment response in children with neuroblastoma. However, this system requires modification to incorporate modern imaging techniques and new methods for quantifying bone marrow disease that were not previously widely available. The National Cancer Institute sponsored a clinical trials planning meeting in 2012 to update and refine response criteria for patients with neuroblastoma. Methods Multidisciplinary investigators from 13 countries reviewed data from published trials performed through cooperative groups, consortia, and single institutions. Data from both prospective and retrospective trials were used to refine the INRC. Monthly international conference calls were held from 2011 to 2015, and consensus was reached through review by working group leadership and the National Cancer Institute Clinical Trials Planning Meeting leadership council. Results Overall response in the revised INRC will integrate tumor response in the primary tumor, soft tissue and bone metastases, and bone marrow. Primary and metastatic soft tissue sites will be assessed using Response Evaluation Criteria in Solid Tumors (RECIST) and iodine-123 (123I) -metaiodobenzylguanidine (MIBG) scans or [18F]fluorodeoxyglucose-positron emission tomography scans if the tumor is MIBG nonavid. 123I-MIBG scans, or [18F]fluorodeoxyglucose-positron emission tomography scans for MIBG-nonavid disease, replace technetium-99m diphosphonate bone scintigraphy for osteomedullary metastasis assessment. Bone marrow will be assessed by histology or immunohistochemistry and cytology or immunocytology. Bone marrow with ≤ 5% tumor involvement will be classified as minimal disease. Urinary catecholamine levels will not be included in response assessment. Overall response will be defined as complete response, partial response, minor response, stable disease, or progressive disease. Conclusion These revised criteria will provide a uniform assessment of disease response, improve the interpretability of clinical trial results, and facilitate collaborative trial designs.

Neuroblastoma: MIBG Imaging and New Tracers

Neuroblastoma is an embryonic tumor of the peripheral sympathetic nervous system, and is metastatic or otherwise high risk for relapse in nearly 50% of cases, with a long-term survival of <40%. Therefore, exact staging with radiological and nuclear medicine imaging methods is crucial for finding the adequate therapeutic choice. The tumor cells express the norepinephrine transporter, which makes metaiodobenzylguanidine (MIBG), an analogue of norepinephrine, an ideal tumor-specific agent for imaging. On the contrary, MIBG imaging has several disadvantages such as limited spatial resolution, limited sensitivity in small lesions, need for two or even more acquisition sessions, and a delay between the start of the examination and result. Most of these limitations can be overcome with positron emission tomography (PET) using different radiotracers. Furthermore, for operative or biopsy planning, a combination with morphological imaging methods is indispensable. This article would discuss the therapeutic strategy for primary and follow-up diagnosis in neuroblastoma using MIBG scintigraphy and different new PET tracers as well as multimodality imaging.

Weak uptake of 123I-MIBG and 18F-FDOPA contrasting with high 18F-FDG uptake in stage I neuroblastoma

Hypertension in a 6-year-old girl was the presenting sign of a stage I neuroblastoma. This tumor corresponded to a left adrenal gland mass. Hypertension resolved immediately after complete surgical resection of the tumor with an uneventful follow-up (24 months at the present time). Preoperative assessment by nuclear medicine techniques showed weak uptake of I-MIBG and F-FDOPA contrasting with high F-FDG uptake by the tumor.

Diagnostic value of 18F-FDG PET/CT in paediatric neuroblastoma: comparison with 131I-MIBG scintigraphy

PURPOSE

The aim of the study was to evaluate the diagnostic value of fluorine-18 fluorodeoxyglucose (18F-FDG) PET/computed tomography (CT) in paediatric patients with neuroblastoma (NB) and compare the results with iodine-131 metaiodobenzylguanidine (131I-MIBG) scintigraphy.

METHODS

Data on 40 paediatric patients (age, 5.5 ± 5.6 years; male, 32; female, eight) with histopathologically proven NB who underwent 18F-FDG PET/CT (staging, 21 patients; restaging/response monitoring, 19 patients) were retrospectively evaluated. I-MIBG scintigraphy data were available for 28/40 patients (median interval, 15 days; staging, 20 patients; restaging/response monitoring, eight patients). 131I-MIBG scintigraphy and 18F-FDG PET/CT images were evaluated by two nuclear medicine physicians in consensus and in separate sessions. Histopathology (n = 50 lesions) and/or clinical/imaging follow-up (n = 90 lesions) data were taken as the reference standard.

RESULTS

Patient-wise sensitivity, specificity, positive-predictive value, negative-predictive value and accuracy of 18F-FDG PET/CT were 100, 50, 91.89, 100 and 92.50%, respectively. A total of 140 lesions (primary, 37; lymph node, 31; bone, 50; bone marrow, 15; and others, seven) were detected on PET/CT. In 28 patients undergoing both imaging studies, the sensitivity, specificity, positive-predictive value, negative-predictive value and accuracy of 18F-FDG PET/CT were 100, 60, 92, 100 and 92.80%, respectively, and those of 131I-MIBG were 95.65, 60, 91.67, 75 and 89.20%, respectively. In these 28 patients, PET/CT detected 107 lesions (primary, 25; lymph node, 22; bone/bone marrow, 56; and others, four) and 131I-MIBG scintigraphy detected 74 lesions (primary, 24; lymph node, five; and bone/bone marrow, 45). On a patient-based comparison there was no significant difference between 18F-FDG PET/CT and 131I-MIBG (P = 1.000), but 18F-FDG PET/CT was superior to 131I-MIBG on a lesion-based comparison (P < 0.0001). Although no difference was noted for primary lesions (P = 1.000), PET/CT was superior to 131I-MIBG scintigraphy for the detection of lymph nodal (P = 0.001) and bone/bone marrow lesions (P = 0.007).

CONCLUSION

18F-FDG PET/CT shows high accuracy in paediatric patients with NB and demonstrates more lesions as compared with 131I-MIBG scintigraphy.

Prognostic value of pretreatment FDG PET in pediatric neuroblastoma

PURPOSE

This study aimed to evaluate the prognostic value of pretreatment (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in pediatric neuroblastoma patients.

METHODS

The study included 50 pediatric neuroblastoma patients who underwent diagnostic work-up FDG PET before any treatment. The maximum standardized uptake value (SUV(max)) of the primary tumor lesion (P(max)), the SUV(max) of all the tumor lesions, including the primary tumor lesion and metastatic lesions (T(max)), and the uptake ratio of T(max) to mean SUV of normal liver tissue (T(max)/L(mean)) were calculated and tested as prognostic factors.

RESULTS

Of the 50 patients, 15 (30.0%) experienced disease progression and 21 (42.0%) died during the follow-up period. On univariate analysis, the histopathology, tumor stage, bone marrow involvement, serum levels of lactate dehydrogenase (LDH), neuron-specific enolase, and ferritin, primary tumor size, P(max), T(max), and T(max)/L(mean) were significant prognostic factors for disease progression-free survival (PFS), whereas the tumor stage, serum level of LDH, T(max), and T(max)/L(mean) were determined to be significant for predicting overall survival (OS). On multivariate analysis, the histopathology and serum level of LDH were independent prognostic factors for PFS, and only the T(max)/L(mean) was an independent prognostic factor for OS. The 2-year PFS and OS rates were over 80.0% in patients with low FDG uptake, meanwhile, patients with high FDG uptake showed the 2-year PFS of less than 30.0% and OS of less than 55.0%.

CONCLUSION

FDG PET was an independent prognostic factor for OS in neuroblastoma patients. FDG PET can provide effective information on the prognosis for neuroblastoma patients.

123I-MIBG scintigraphy and 18F-FDG-PET imaging for diagnosing neuroblastoma

BACKGROUND

Neuroblastoma is an embryonic tumour of childhood that originates in the neural crest. It is the second most common extracranial malignant solid tumour of childhood.Neuroblastoma cells have the unique capacity to accumulate Iodine-123-metaiodobenzylguanidine (¹²³I-MIBG), which can be used for imaging the tumour. Moreover, ¹²³I-MIBG scintigraphy is not only important for the diagnosis of neuroblastoma, but also for staging and localization of skeletal lesions. If these are present, MIBG follow-up scans are used to assess the patient's response to therapy. However, the sensitivity and specificity of ¹²³I-MIBG scintigraphy to detect neuroblastoma varies according to the literature.Prognosis, treatment and response to therapy of patients with neuroblastoma are currently based on extension scoring of ¹²³I-MIBG scans. Due to its clinical use and importance, it is necessary to determine the exact diagnostic accuracy of ¹²³I-MIBG scintigraphy. In case the tumour is not MIBG avid, fluorine-18-fluorodeoxy-glucose ((18)F-FDG) positron emission tomography (PET) is often used and the diagnostic accuracy of this test should also be assessed.

OBJECTIVES

PRIMARY OBJECTIVES

1.1 To determine the diagnostic accuracy of ¹²³I-MIBG (single photon emission computed tomography (SPECT), with or without computed tomography (CT)) scintigraphy for detecting a neuroblastoma and its metastases at first diagnosis or at recurrence in children from 0 to 18 years old.1.2 To determine the diagnostic accuracy of negative ¹²³I-MIBG scintigraphy in combination with (18)F-FDG-PET(-CT) imaging for detecting a neuroblastoma and its metastases at first diagnosis or at recurrence in children from 0 to 18 years old, i.e. an add-on test.

SECONDARY OBJECTIVES

2.1 To determine the diagnostic accuracy of (18)F-FDG-PET(-CT) imaging for detecting a neuroblastoma and its metastases at first diagnosis or at recurrence in children from 0 to 18 years old.2.2 To compare the diagnostic accuracy of ¹²³I-MIBG (SPECT-CT) and (18)F-FDG-PET(-CT) imaging for detecting a neuroblastoma and its metastases at first diagnosis or at recurrence in children from 0 to 18 years old. This was performed within and between included studies. ¹²³I-MIBG (SPECT-CT) scintigraphy was the comparator test in this case.

SEARCH METHODS

We searched the databases of MEDLINE/PubMed (1945 to 11 September 2012) and EMBASE/Ovid (1980 to 11 September 2012) for potentially relevant articles. Also we checked the reference lists of relevant articles and review articles, scanned conference proceedings and searched for unpublished studies by contacting researchers involved in this area.

SELECTION CRITERIA

We included studies of a cross-sectional design or cases series of proven neuroblastoma, either retrospective or prospective, if they compared the results of ¹²³I-MIBG (SPECT-CT) scintigraphy or (18)F-FDG-PET(-CT) imaging, or both, with the reference standards or with each other. Studies had to be primary diagnostic and report on children aged between 0 to 18 years old with a neuroblastoma of any stage at first diagnosis or at recurrence.

DATA COLLECTION AND ANALYSIS

One review author performed the initial screening of identified references. Two review authors independently performed the study selection, extracted data and assessed the methodological quality.We used data from two-by-two tables, describing at least the number of patients with a true positive test and the number of patients with a false negative test, to calculate the sensitivity, and if possible, the specificity for each included study.If possible, we generated forest plots showing estimates of sensitivity and specificity together with 95% confidence intervals.

MAIN RESULTS

Eleven studies met the inclusion criteria. Ten studies reported data on patient level: the scan was positive or negative. One study reported on all single lesions (lesion level). The sensitivity of ¹²³I-MIBG (SPECT-CT) scintigraphy (objective 1.1), determined in 608 of 621 eligible patients included in the 11 studies, varied from 67% to 100%. One study, that reported on a lesion level, provided data to calculate the specificity: 68% in 115 lesions in 22 patients. The sensitivity of ¹²³I-MIBG scintigraphy for detecting metastases separately from the primary tumour in patients with all neuroblastoma stages ranged from 79% to 100% in three studies and the specificity ranged from 33% to 89% for two of these studies.One study reported on the diagnostic accuracy of (18)F-FDG-PET(-CT) imaging (add-on test) in patients with negative ¹²³I-MIBG scintigraphy (objective 1.2). Two of the 24 eligible patients with proven neuroblastoma had a negative ¹²³I-MIBG scan and a positive (18)F-FDG-PET(-CT) scan.The sensitivity of (18)F-FDG-PET(-CT) imaging as a single diagnostic test (objective 2.1) and compared to ¹²³I-MIBG (SPECT-CT) (objective 2.2) was only reported in one study. The sensitivity of (18)F-FDG-PET(-CT) imaging was 100% versus 92% of ¹²³I-MIBG (SPECT-CT) scintigraphy. We could not calculate the specificity for both modalities.

AUTHORS' CONCLUSIONS

The reported sensitivities of ¹²³-I MIBG scintigraphy for the detection of neuroblastoma and its metastases ranged from 67 to 100% in patients with histologically proven neuroblastoma.Only one study in this review reported on false positive findings. It is important to keep in mind that false positive findings can occur. For example, physiological uptake should be ruled out, by using SPECT-CT scans, although more research is needed before definitive conclusions can be made.As described both in the literature and in this review, in about 10% of the patients with histologically proven neuroblastoma the tumour does not accumulate ¹²³I-MIBG (false negative results). For these patients, it is advisable to perform an additional test for staging and assess response to therapy. Additional tests might for example be (18)F-FDG-PET(-CT), but to be certain of its clinical value, more evidence is needed.The diagnostic accuracy of (18)F-FDG-PET(-CT) imaging in case of a negative ¹²³I-MIBG scintigraphy could not be calculated, because only very limited data were available. Also the detection of the diagnostic accuracy of index test (18)F-FDG-PET(-CT) imaging for detecting a neuroblastoma tumour and its metastases, and to compare this to comparator test ¹²³I-MIBG (SPECT-CT) scintigraphy, could not be calculated because of the limited available data at time of this search.At the start of this project, we did not expect to find only very limited data on specificity. We now consider it would have been more appropriate to use the term "the sensitivity to assess the presence of neuroblastoma" instead of "diagnostic accuracy" for the objectives.

Usefulness of 18F-Fluorodeoxyglucose Positron Emission Tomography for Follow-Up of 13-cis-Retinoic Acid Treatment for Residual Neuroblastoma After Myeloablative Chemotherapy

13-cis-retinoic acid (13-cis-RA) treatment is used as a second-line treatment for residual or recurrent neuroblastoma. However, determining the duration of 13-cis-RA treatment for residual and recurrent neuroblastoma can be a problem because it is difficult to evaluate the effectiveness of the treatment.We performed 13-cis-RA treatment to remove residual active neuroblastoma cells in an 8-year-old boy with stage 4 neuroblastoma that developed from a left sympathetic ganglion and had been treated with chemotherapy, surgery, autologous peripheral blood stem-cell transplantation, and radiotherapy. F-fluorodeoxyglucose positron emission tomography (F-FDG-PET) and iodine-123 metaiodobenzylguanidine (I-MIBG) scintigraphy obtained immediately before 13-cis-RA treatment both showed positive findings in the area of the primary lesion. At 18 months after 13-cis-RA treatment, there was accumulation on I-MIBG scintigraphy but no uptake on F-FDG-PET, and 13-cis-RA treatment was suspended. The patient has been in complete remission for 3 years. In comparing the effectiveness of the 2 imaging modalities for monitoring the response to 13-cis-RA treatment, we considered that F-FDG-PET was superior to I-MIBG scintigraphy because F-FDG-PET images were not affected by the cell differentiation induced by 13-cis-RA treatment in our case. Thus, F-FDG-PET was useful for determining the treatment response and outcomes.We have reported a case of residual neuroblastoma treated with differentiation-inducing 13-cis-RA therapy. Different results were produced with F-FDG-PET and I-MIBG scintigraphy. The cessation of 13-cis-RA treatment was based on F-FDG-PET findings and there has been no relapse for 3 years.

Imaging in neuroblastoma: An update

Neuroblastoma is the third common tumor in children. Imaging plays an important role in the diagnosis, staging, treatment planning, response evaluation and in follow-up of a case of Neuroblastoma. The International Neuroblastoma Risk Group task force has recently introduced an imaging-based staging system and laid down guidelines for uniform reporting of imaging studies. This review is an update on imaging in neuroblastoma, with emphasis on these guidelines.

2-deoxy-2-(18F)fluoro-D-glucose positron emission tomography/computed tomography imaging in paediatric oncology

Positron emission tomography (PET) is a minimally invasive technique which has been well validated for the diagnosis, staging, monitoring of response to therapy, and disease surveillance of adult oncology patients. Traditionally the value of PET and PET/computed tomography (CT) hybrid imaging has been less clearly defined for paediatric oncology. However recent evidence has emerged regarding the diagnostic utility of these modalities, and they are becoming increasingly important tools in the evaluation and monitoring of children with known or suspected malignant disease. Important indications for 2-deoxy-2-(¹⁸F)fluoro-D-glucose (FDG) PET in paediatric oncology include lymphoma, brain tumours, sarcoma, neuroblastoma, Langerhans cell histiocytosis, urogenital tumours and neurofibromatosis type I. This article aims to review current evidence for the use of FDG PET and PET/CT in these indications. Attention will also be given to technical and logistical issues, the description of common imaging pitfalls, and dosimetric concerns as they relate to paediatric oncology.

Clinical experience with (18)F-fluorodeoxyglucose positron emission tomography and (123)I-metaiodobenzylguanine scintigraphy in pediatric neuroblastoma: complementary roles in follow-up of patients

Purpose

To evaluate the potential utility of ¹²³I-metaiodobenzylguanine (¹²³I-MIBG) scintigraphy and ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET) for the detection of primary and metastatic lesions in pediatric neuroblastoma (NBL) patients, and to determine whether ¹⁸F-FDG PET is as beneficial as ¹²³I-MIBG imaging.

Methods

We selected 8 NBL patients with significant residual mass after operation and who had paired ¹²³I-MIBG and ¹⁸F-FDG PET images that were obtained during the follow-up. We retrospectively reviewed the clinical charts and the findings of 45 paired scans.

Results

Both scans correlated relatively well with the disease status as determined by standard imaging modalities during follow-up; the overall concordance rates were 32/45 (71.1%) for primary tumor sites and 33/45 (73.3%) for bone-bone marrow (BM) metastatic sites. In detecting primary tumor sites, ¹²³I-MIBG might be superior to ¹⁸F-FDG PET. The sensitivity of ¹²³I-MIBG and ¹⁸F-FDG PET were 96.7% and 70.9%, respectively, and their specificity were 85.7% and 92.8%, respectively. ¹⁸F-FDG PET failed to detect 9 true NBL lesions in 45 follow-up scans (false negative rate, 29%) with positive ¹²³I-MIBG. For bone-BM metastatic sites, the sensitivity of ¹²³I-MIBG and ¹⁸F-FDG PET were 72.7% and 81.8%, respectively, and the specificity were 79.1% and 100%, respectively. ¹²³I-MIBG scan showed higher false positivity (20.8%) than ¹⁸F-FDG PET (0%).

Conclusion

¹²³I-MIBG is superior for delineating primary tumor sites, and ¹⁸F-FDG PET could aid in discriminating inconclusive findings on bony metastatic NBL. Both scans can be complementarily used to clearly determine discrepancies or inconclusive findings on primary or bone-BM metastatic NBL during follow-up.

Imaging the norepinephrine transporter in neuroblastoma: a comparison of [18F]-MFBG and 123I-MIBG

PURPOSE

The norepinephrine transporter (NET) is a critical regulator of catecholamine uptake in normal physiology and is expressed in neuroendocrine tumors like neuroblastoma. Although the norepinephrine analog, meta-iodobenzylguanidine (MIBG), is an established substrate for NET, (123)I/(131)I-MIBG has several clinical limitations for diagnostic imaging. In the current studies, we evaluated meta-[(18)F]-fluorobenzylguanidine ([(18)F]-MFBG) and compared it with (123)I-MIBG for imaging NET-expressing neuroblastomas.

EXPERIMENTAL DESIGN

NET expression levels in neuroblastoma cell lines were determined by Western blot and (123)I-MIBG uptake assays. Five neuroblastoma cell lines and two xenografts (SK-N-BE(2)C and LAN1) expressing different levels of NET were used for comparative in vitro and in vivo uptake studies.

RESULTS

The uptake of [(18)F]-MFBG in cells was specific and proportional to the expression level of NET. Although [(18)F]-MFBG had a 3-fold lower affinity for NET and an approximately 2-fold lower cell uptake in vitro compared with that of (123)I-MIBG, the in vivo imaging and tissue radioactivity concentration measurements demonstrated higher [(18)F]-MFBG xenograft uptake and tumor-to-normal organ ratios at 1 and 4 hours after injection. A comparison of 4 hours [(18)F]-MFBG PET (positron emission tomography) imaging with 24 hours (123)I-MIBG SPECT (single-photon emission computed tomography) imaging showed an approximately 3-fold higher tumor uptake of [(18)F]-MFBG, but slightly lower tumor-to-background ratios in mice.

CONCLUSIONS

[(18)F]-MFBG is a promising radiopharmaceutical for specifically imaging NET-expressing neuroblastomas, with fast pharmacokinetics and whole-body clearance. [(18)F]-MFBG PET imaging shows higher sensitivity, better detection of small lesions with low NET expression, allows same day scintigraphy with a shorter image acquisition time, and has the potential for lower patient radiation exposure compared with (131)I/(123)I-MIBG.

(18)F-FDG PET as a single imaging modality in pediatric neuroblastoma: comparison with abdomen CT and bone scintigraphy

OBJECTIVE

The purpose of this study was to evaluate the diagnostic performance of (18)F-fluoro-2-deoxy-D-glucose positron emission tomography (FDG PET) as a single imaging agent in neuroblastoma in comparison with other imaging modalities.

METHODS

A total of 30 patients with pathologically proven neuroblastoma who underwent FDG PET for staging were enrolled. Diagnostic performance of FDG PET and abdomen CT was compared in detecting soft tissue lesions. FDG PET and bone scintigraphy (BS) were compared in bone metastases. Maximal standardized uptake value (SUVmax) of primary or recurrent lesions was calculated for quantitative analysis.

RESULTS

Tumor FDG uptake was detected in 29 of 30 patients with primary neuroblastoma. On initial FDG PET, SUVmax of primary lesions were lower in early stage (I-II) than in late stage (III-IV) (3.03 vs. 5.45, respectively, p = 0.019). FDG PET was superior to CT scan in detecting distant lymph nodes (23 vs. 18 from 23 lymph nodes). FDG PET showed higher accuracy to identify bone metastases than BS both on patient-based analyses (100 vs. 94.4 % in sensitivity, 100 vs. 77.8 % in specificity), and on lesion-based analyses (FDG PET: 203 lesions, BS: 86 lesions). Sensitivity and specificity of FDG PET to detect recurrence were 87.5 % and 93.8, respectively.

CONCLUSION

FDG PET was superior to CT in detecting distant LN metastasis and to BS in detecting skeletal metastasis in neuroblastoma. BS might be eliminated in the evaluation of neuroblastoma when FDG PET is performed.

Molecular imaging of neuroblastoma progression in TH-MYCN transgenic mice

PURPOSE

TH-MYCN transgenic mice represent a valuable preclinical model of neuroblastoma. Current methods to study tumor progression in these mice are inaccurate or invasive, limiting the potential of this murine model. The aim of our study was to assess the potential of small animal positron emission tomography (SA-PET) to study neuroblastoma progression in TH-MYCN mice.

PROCEDURE

Serial SA-PET scans using the tracer 2-deoxy-2-[(18)F]fluoro-D-glucose ((18)F-FDG) have been performed in TH-MYCN mice. Image analysis of tumor progression has been compared with ex vivo evaluation of tumor volumes and histological features.

RESULTS

[(18)F]FDG-SA-PET allowed to detect early staged tumors in almost 100 % of TH-MYCN mice positive for disease. Image analysis of tumor evolution reflected the modifications of the tumor volume, histological features, and malignancy during disease progression. Image analysis of TH-MYCN mice undergoing chemotherapy treatment against neuroblastoma provided information on drug-induced alterations in tumor metabolic activity.

CONCLUSIONS

These data show for the first time that [(18)F]FDG-SA-PET is a useful tool to study neuroblastoma presence and progression in TH-MYCN transgenic mice.

Nuclear medicine and multimodality imaging of pediatric neuroblastoma

Neuroblastoma is an embryonic tumor of the peripheral sympathetic nervous system and is metastatic or high risk for relapse in nearly 50% of cases. Therefore, exact staging with radiological and nuclear medicine imaging methods is crucial for defining the adequate therapeutic choice. Tumor cells express the norepinephrine transporter, which makes metaiodobenzylguanidine (MIBG), an analogue of norepinephrine, an ideal tumor specific agent for imaging. MIBG imaging has several disadvantages, such as limited spatial resolution, limited sensitivity in small lesions and the need for two or even more acquisition sessions. Most of these limitations can be overcome with positron emission tomography (PET) using [F-18]2-fluoro-2-deoxyglucose [FDG]. Furthermore, new tracers, such as fluorodopa or somatostatin receptor agonists, have been tested for imaging neuroblastoma recently. However, MIBG scintigraphy and PET alone are not sufficient for operative or biopsy planning. In this regard, a combination with morphological imaging is indispensable. This article will discuss strategies for primary and follow-up diagnosis in neuroblastoma using different nuclear medicine and radiological imaging methods as well as multimodality imaging.

Ten challenges in the management of neuroblastoma

Neuroblastoma is a complex disease with many contradictions and challenges. It is, by and large, a cancer of babies and preschool children, but it does occur, albeit increasingly rarely, in older children, adolescents and young adults. The prognosis is very variable, with outcome related to age, stage and molecular pathology. Neuroblastoma may behave in an almost benign way, with spontaneous regression in some infants, but the majority of older patients have high-risk disease, which is usually fatal, despite best current treatments. As a rare disease, international collaboration is essential to run clinical trials of adequate statistical power to answer important questions in a reasonable time frame. High-risk disease requires multimodality therapy including chemotherapy, surgery and radiotherapy as well as biological and immunological treatments for optimal outcomes. Innovative treatment approaches, sometimes associated with appreciable toxicity, offer hope for the future but, despite parental wishes, cannot be generally implemented without adequate assessment in clinical trials.

PET/MR in children. Initial clinical experience in paediatric oncology using an integrated PET/MR scanner

Use of PET/MR in children has not previously been reported, to the best of our knowledge. Children with systemic malignancies may benefit from the reduced radiation exposure offered by PET/MR. We report our initial experience with PET/MR hybrid imaging and our current established sequence protocol after 21 PET/MR studies in 15 children with multifocal malignant diseases. The effective dose of a PET/MR scan was only about 20% that of the equivalent PET/CT examination. Simultaneous acquisition of PET and MR data combines the advantages of the two previously separate modalities. Furthermore, the technique also enables whole-body diffusion-weighted imaging (DWI) and statements to be made about the biological cellularity and nuclear/cytoplasmic ratio of tumours. Combined PET/MR saves time and resources. One disadvantage of PET/MR is that in order to have an effect, a significantly longer examination time is needed than with PET/CT. In our initial experience, PET/MR has turned out to be an unexpectedly stable and reliable hybrid imaging modality, which generates a complementary diagnostic study of great additional value.

Molecular imaging of adrenal neoplasms

The adrenal glands are complex structures from which a variety of benign and malignant tumors may arise and are a common site of metastatic disease. Several radiopharmaceuticals are used for imaging the adrenals, including I-123/I-131 metaiodobenzylguanidine (MIBG), norcholesterol derivatives, In-111 pentetreotide and Ga-68 somatostatin analogs, [F-18]fluorodeoxyglucose, [F-18]fluorodopa, [F-18]fluorodopamine, C-11 meta hydroxyephedrine, and C-11/F-18/I-123 Metomidate (MTO) or its analogs. In this review we focus on the role of these reagents in metastatic lesions, cortical neoplasms, pheochromocytoma/paraganglioma, and neuroblastoma (NB).

Comparison of 18F-dopa PET/CT and 123I-MIBG scintigraphy in stage 3 and 4 neuroblastoma: a pilot study

PURPOSE

(18)F-Dopa positron emission tomography (PET)/CT has proved a valuable tool for the assessment of neuroendocrine tumours. So far no data are available on (18)F-dopa utilization in neuroblastoma (NB). Our aim was to evaluate the role of (18)F-dopa PET/CT in NB and compare its diagnostic value with that of (123)I-metaiodobenzylguanidine (MIBG) scintigraphy in patients affected by stage 3-4 NB.

METHODS

We prospectively evaluated 28 paired (123)I-MIBG and (18)F-dopa PET/CT scans in 19 patients: 4 at the time of the NB diagnosis and 15 when NB relapse was suspected. For both imaging modalities we performed a scan-based and a lesion-based analysis and calculated sensitivity, specificity and accuracy. The standard of reference was based on clinical, imaging and histological data.

RESULTS

NB localizations were confirmed in 17 of 19 patients. (18)F-Dopa PET/CT and (123)I-MIBG scintigraphy properly detected disease in 16 (94%) and 11 (65%), respectively. On scan-based analysis, (18)F-dopa PET/CT showed a sensitivity and accuracy of 95 and 96%, respectively, while (123)I-MIBG scanning showed a sensitivity and accuracy of 68 and 64%, respectively (p < 0.05). No significant difference in terms of specificity was found. In 9 of 28 paired scans (32%) PET/CT results influenced the patient management. We identified 156 NB localizations, 141 of which were correctly detected by (18)F-dopa PET/CT and 88 by MIBG. On lesion-based analysis, (18)F-dopa PET/CT showed a sensitivity and accuracy of 90% whereas (123)I-MIBG scintigraphy showed a sensitivity and accuracy of 56 and 57%, respectively (p < 0.001). No significant difference in terms of specificity was found.

CONCLUSION

In our NB population (18)F-dopa PET/CT displayed higher overall accuracy than (123)I-MIBG scintigraphy. Consequently, we suggest (18)F-dopa PET/CT as a new opportunity for NB assessment.