Increased Gastric MIBG Activity as a Normal Variant

Leptomeningeal Metastasis From Neuroblastoma Revealed by 123 I-MIBG SPECT/CT

ABSTRACT

A 2-year-old girl with history of high-risk neuroblastoma underwent 123 I-MIBG, which showed increased 123 I-MIBG in the left side of the head. Contrast-enhanced MRI and cerebral spine fluid cytology confirmed the diagnosis of leptomeningeal metastasis.

[18F]MFBG PET/CT outperforming [123I]MIBG SPECT/CT in the evaluation of neuroblastoma

PURPOSE

Iodine 123 labeled meta-iodobenzylguanidine ([123I]MIBG) scan with SPECT/CT imaging is one of the most commonly used imaging modalities in the evaluation of neuroblastoma. [18F]-meta-fluorobenzylguanidine ([18F]MFBG) is a novel positron emission tomography (PET) tracer which was reported to have a similar biodistribution to [123I]MIBG. However, the experience of using [18F]MFBG PET/CT in the evaluation of patients with neuroblastoma is limited. This preliminary investigation aims to assess the efficacy of [18F]MFBG PET/CT in the evaluation of neuroblastomas in comparison to [123I]MIBG scans with SPECT/CT.

MATERIALS AND METHODS

In this prospective, single-center study, 40 participants (mean age 6.0 ± 3.7 years) with history of neuroblastoma were enrolled. All children underwent both [123I]MIBG SPECT/CT and [18F]MFBG PET/CT studies. The number of lesions and the Curie scores revealed by each imaging method were recorded.

RESULTS

Six patients had negative findings on both [123I]MIBG and [18F]MFBG studies. Four of the 34 patients (11.8%) were negative on [123I]MIBG but positive on [18F]MFBG, while 30 patients were positive on both [123I]MIBG and [18F]MFBG studies. In these 34 patients, [18F]MFBG PET/CT identified 784 lesions while [123I]MIBG SPECT/CT detected 532 lesions (p < 0.001). The Curie scores obtained from [18F]MFBG PET/CT (11.32 ± 8.18, range 1-27) were statistically higher (p < 0.001) than those from [123I]MIBG SPECT/CT (7.74 ± 7.52, range 0-26). 30 of 34 patients (88.2%) with active disease on imaging had higher Curie scores based on the [18F]MFBG study than on the [123I]MIBG imaging.

CONCLUSION

[18F]MFBG PET/CT shows higher lesion detection rate than [123I]MIBG SPECT/CT in the evaluation of pediatric patients with neuroblastoma.

CLINICAL TRIAL REGISTRATION

Clinicaltrials.gov : NCT05069220 (Registered: 25 September 2021, retrospectively registered); Institute Review Board of Peking Union Medical College Hospital: ZS-2514.

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.

MIBG Uptake in a Gastric Gastrointestinal Stromal Tumor

ABSTRACT

MIBG scintigraphy is the imaging choice in the evaluation of pheochromocytoma and neuroblastoma. 131 I-MIBG uptake by gastrointestinal stromal tumors was rare. Here we report a case in which an increased 131 I-MIBG activity in an endoluminal gastric gastrointestinal stromal tumor was noted.

MIBG Uptake in Pancreas as a Normal Variant

ABSTRACT

A 5-year-old girl with high-risk neuroblastoma underwent 123I-MIBG scintigraphy for disease restaging. The whole-body images showed a faint MIBG uptake in the midabdomen. Abdominal SPECT/CT demonstrated the focus locating in the pancreatic head. However, this activity disappeared on delayed acquisition at 6-hour later. Follow-up MIBG scan after 6 months did not show the abnormal MIBG uptake in the pancreatic head. Delayed scan could be helpful for differential diagnosis.

Elevated 123I-MIBG Activity in Intramuscular Hemangioma

ABSTRACT

A 3-year-old boy with high-risk neuroblastoma underwent 123I-MIBG scan to evaluate the disease status after surgery and chemotherapy. 123I-MIBG SPECT/CT demonstrated liver metastasis. In addition, mildly increased uptake in the inferior left erector spinae was noted. Contrast-enhanced CT suggested intramuscular hemangioma. The 123I-MIBG accumulation in the intramuscular hemangioma persisted during the follow-up scan, whereas the abnormal activity in the liver was resolved.

High-specific-activity 131iodine-metaiodobenzylguanidine for therapy of unresectable pheochromocytoma and paraganglioma

Pheochromocytomas and paragangliomas (PPG) are rare cancers arising from the adrenal medulla (pheochromocytoma) or autonomic ganglia (paraganglioma). They have highly variable biological behavior. Most PPG express high-affinity norepinephrine transporters, allowing active uptake of the norepinephrine analog, ¹³¹iodine-metaiodobenzylguanidine (¹³¹I-MIBG). Low-specific-activity forms of ¹³¹I-MIBG have been used since 1983 for therapy of PPG. High-specific-activity ¹³¹I-MIBG therapy improves hypertension management, induces partial radiological response or stable disease, decreases biochemical markers of disease activity and is well tolerated by patients. This drug, approved in the USA in July 2018, is the first approved agent for patients with unresectable, locally advanced or metastatic PPG and imaging evidence of metaiodobenzylguanidine uptake, who require systemic anticancer therapy.

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.

Renal Metastasis From Neuroblastoma Shown on MIBG Imaging

A 6-year-old girl with high-risk neuroblastoma underwent a I-MIBG scan to monitor the disease status. In addition to the known lesion in the right retroperitoneal region, there were additional foci of increased activity in the right upper quadrate of the abdomen, which were not typical bowel activity. SPECT/CT images located the activity in the cortex of the lower pole of the right kidney, which was partially calcified. Subsequent biopsy confirmed neuroblastoma metastasis to the right kidney, which is extremely rare.