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123I-metaiodobenzylguanidine scintigraphy is used to differentiate Lewy body disease from other neurodegenerative disorders. We identified 2 cases with remarkably changed pulmonary uptake between 2 metaiodobenzylguanidine scintigraphies; pulmonary uptake was reduced when patients were taking selective serotonin reuptake inhibitor/serotonin noradrenaline reuptake inhibitor and preserved during the medication-naive or withdrawal state, suggesting that pulmonary uptake involves not only the noradrenaline transporter, but also the serotonin transporter. Pulmonary accumulation may affect the heart-to-mediastinum ratio as the region of interest on the planner image is usually placed on the heart and includes part of the lung. Therefore, we should pay attention to the medication state of patients with decreased pulmonary uptake.

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.

We report the case of a 75-year-old woman with liver metastasis as a recurrence of a pheochromocytoma resected 10 years ago, with a rare germline mutation in transmembrane protein 127, falsely negative on 18F-FDOPA and 18F-FDG PET/CT scans but strongly positive on 123I-MIBG scintigraphy and on 68Ga-DOTATOC PET/CT. Functional imaging has a key role in diagnosis of pheochromocytoma and paraganglioma, especially 18F-FDOPA shows very high sensitivity and specificity. However, 18F-FDOPA might be falsely negative in some of these tumors, depending on specific mutations, and thus MIBG or 68Ga-DOTATOC imaging could be an alternative.

Purpose The aim of the study is to evaluate the impact of myocardial I-metaiodobenzylguanidine (MIBG) in the diagnosis, clinical management, and differential diagnosis of Parkinson disease (PD) and non-PD parkinsonism. Methods The study enrolled 41 patients with parkinsonism. An initial diagnosis was reached after thorough clinical and imaging evaluation. After 2 to 5 years of follow-up, a final diagnosis was established. All patients underwent, soon after their initial visit, presynaptic striatal DaT scintigraphy with I-FP-CIT (DaTscan) and I-MIBG myocardial scintigraphy. DaTscan is not specific to distinguish among different types of neurodegenerative parkinsonism. I-MIBG myocardial scintigraphy displays the functional status of cardiac sympathetic nerves, which is reduced in PD/dementia with Lewy bodies (DLB) and normal in atypical parkinsonian syndromes and secondary or nondegenerative parkinsonism. Results No patients showed adverse effects during or after both scintigraphies. A positive DaTscan was found in all patients in the PD/DLB group (17/17) and in 15 of 24 patients in the non-PD group. Myocardial I-MIBG scintigraphy was associated with lower sensitivity (82% vs 100%) but higher specificity than DaTscan (79% vs 38%) in diagnosis PD/DLB from non-PD parkinsonism. A positive scan result on both techniques, to confirm diagnosis of PD/DLB, significantly improved the specificity of DaTscan, from 38% to 75%, with no reduction in sensitivity. Conclusions Myocardial I-MIBG imaging provides complementary value to I-FP-CIT in the proper diagnosis, treatment plan, and differential diagnosis between PD and other forms of parkinsonism.

Purpose To evaluate detailed organ-based radiation-absorbed dose for planning double high-dose treatment with I-MIBG. Methods In a prospective study, 33 patients with high-risk refractory or recurrent neuroblastoma were treated with high-dose I-MIBG. Organ dosimetry was estimated from the first I-MIBG posttherapy imaging and from subsequent I-MIBG imaging prior to the planned second administration. Three serial whole-body scans were performed per patient 2 to 6 days after I-MIBG therapy (666 MBq/kg or 18 mCi/kg) and approximately 0.5, 24, and 48 hours after the diagnostic I-MIBG dose (370 MBq/kg or 10 mCi/1.73 m). Organ radiation doses were calculated using OLINDA. I-MIBG scan dosimetry estimations were used to predict doses for the second I-MIBG therapy and compared with I-MIBG posttherapy estimates. Results Mean ± SD whole-body doses from I-MIBG and I-MIBG scans were 0.162 ± 112 and 0.141 ± 0.068 mGy/MBq, respectively. I-MIBG and I-MIBG organ doses were variable-generally higher for I-MIBG-projected doses than those projected using posttherapy I-MIBG scans. Mean ± SD doses to liver, heart wall, and lungs were 0.487 ± 0.28, 0.225 ± 0.20, and 0.40 ± 0.26, respectively, for I-MIBG and 0.885 ± 0.56, 0.618 ± 0.37, and 0.458 ± 0.56, respectively, for I-MIBG. Mean ratio of I-MIBG to I-MIBG estimated radiation dose was 1.81 ± 1.95 for the liver, 2.75 ± 1.84 for the heart, and 1.13 ± 0.93 for the lungs. No unexpected toxicities were noted based on I-MIBG-projected doses and cumulative dose limits of 30, 20, and 15 Gy to liver, kidneys, and lungs, respectively. Conclusions For repeat I-MIBG treatment planning, both I-MIBG and I-MIBG imaging yielded variable organ doses. However, I-MIBG-based dosimetry yielded a more conservative estimate of maximum allowable activity and would be suitable for planning and limiting organ toxicity with repeat high-dose therapies.

A 30-year-old man presented with repeated episodes of painless injuries in his feet and abnormally high body temperature. He was diagnosed with congenital insensitivity to pain with anhidrosis-a rare hereditary peripheral neuropathy characterized by decreased pain, reduced sweating, and autonomic neuropathy. Congenital insensitivity to pain with anhidrosis is also called hereditary sensory and autonomic neuropathy type IV. 123I-MIBG myocardial scintigraphy showed reduced myocardial uptake (heart-to-mediastinum ratio: 1.56 and 1.42 in the early and late phases, respectively; washout ratio, 49%), indicating autonomic dysfunction. This finding may contribute to the diagnosis of congenital insensitivity to pain with anhidrosis and the semiquantitative evaluation of an autonomic dysfunction.

This retrospective study compared the diagnostic performances of quantitative versus visual analyses of I-MIBG scintigraphy in patients with suspected pheochromocytoma and paraganglioma (PPGL).SPECT images were obtained 6 and/or 24 h after MIBG injection from 68 patients with clinically suspected PPGL, with attenuation correction by low-dose unenhanced CT. Planar images were also obtained at each time point. SUVs of retroperitoneal tumors, including PPGLs, and physiological uptake by normal organs were measured using the SPECT images. The diagnostic performance of the quantitative assessment in differentiating PPGLs from other lesions or normal adrenal glands was assessed using receiver operating characteristic analysis. The planar scans and 6-h and 24-h SPECT/CT images were also assessed visually.PPGLs showed a significantly higher SUVmax (mean ± SD = 9.97 ± 3.86) than other retroperitoneal lesions (3.85 ± 1.51) or normal adrenal glands (3.91 ± 1.20). At an optimal cut-off of 6.57, the sensitivity, specificity, and accuracy of the quantitative assessment for 6-h SPECT/CT in differentiating PPGLs was 78.6%, 96.3%, and 92.6%, respectively; the area under the curve was 0.878. The diagnostic performance did not significantly differ between the quantitative and visual analyses, but the specificity of the former tended to be higher at 6 h (96.3% vs. 90.7%) and at 24 h (91.2% vs. 82.4%).The specificity, but not the sensitivity, of the quantitative approach was higher than that of visual assessment in differentiating PPGLs from other retroperitoneal pathologies and from physiological uptake in the normal adrenal gland.

An 84-year-old man with parkinsonism was referred for I-MIBG scintigraphy. Abnormal uptake in the right upper abdomen was incidentally seen in planar image, and SPECT revealed focal uptake in the medial segment (S4) of the liver. Subsequent triple-phase contrast-enhanced CT showed no evidence of hepatic tumors, although in the arterial phase, there were an enhanced region corresponding to the uptake area and the enhanced vein of Sappey that flowed into S4. In this case, the focal I-MIBG uptake would be attributable to hemodynamic change in the liver.

We report a case of an adult male patient with multifocal urinary bladder paragangliomas, which were negative on Ga-DOTATATE PET/CT scan, but positive on I-MIBG SPECT/CT scan. While the Ga-DOTA analog PET/CT exhibits superior performance in diagnosis and staging of pheochromocytoma and paraganglioma, our case demonstrates negative somatostatin receptor expression in this rare entity and indicates that I-MIBG SPECT/CT still plays a vital role in characterization of bladder paraganglioma.

Pediatric cancer imaging stands to benefit from higher tumor detection sensitivity without ionizing radiation exposure. A prospective protocol compared diagnostic I-metaiodobenzylguanidine (I-mIBG) with whole-body diffusion-weighted MRI (DWI) to validate adjunctive methods of identifying small-volume oligometastatic neuroblastoma tumor deposits. Dual-modality imaging (I-mIBG and DWI) was obtained within a 3- and 25-day window at baseline and again at one year in the first enrolled patient. MRI was able to define the full extent of metastatic disease foci with improved resolution. These findings may provide critical information for definitive locoregional surgery and radiotherapy for high-risk neuroblastoma treatment.

To determine the diagnostic performance of ¹²³I-metaiodobenzylguanidine (mIBG) SPECT/MRI fusion, ¹²³I-mIBG SPECT/CT and adrenal MRI for the detection of pheochromocytoma in patients with elevated urine or plasma catecholamines.Twenty-two consecutive patients underwent both a whole-body ¹²³I-mIBG scan with SPECT/CT of the adrenal region and MRI of the adrenal glands. Fused SPECT/MRI, SPECT/CT, and MRI scans were evaluated. Imaging results were analyzed both on a per-patient and on a per-lesion basis. Histopathology and/or clinical and radiological follow-up served as the reference standard.Sixteen adrenal tumors were found in thirteen patients. On a per-lesion basis, SPECT/CT had a sensitivity of 87.5%, a specificity of 93.8%, and an overall accuracy of 92.5%. MRI had a sensitivity of 87.5%, a specificity of 96.9%, and an overall accuracy of 95.0%. On a per-patient basis, both SPECT/CT and MRI had a sensitivity of 85.7%, a specificity of 93.3%, and an overall accuracy of 90.9%. SPECT/CT was concordant with MRI in 81.8% of cases. SPECT/MRI fusion was superior to both SPECT/CT and MRI and had a sensitivity of 100% on both a per-lesion and a per-patient basis.¹²³I-mIBG SPECT/MRI has the highest sensitivity and accuracy for the detection and localization of pheochromocytomas. SPECT/CT and MRI of the adrenal glands are equivalent diagnostic procedures. However, MRI offers the advantage of fully diagnostic assessment of adrenal lesions other than pheochromocytoma undetectable by ¹²³I-mIBG.

The aim of our study was to evaluate the use of dopamine transporter (DAT) SPECT and I-MIBG myocardial scintigraphy to determine the clinical severity of Parkinson disease (PD), with a focus on motor impairments affecting activities of daily living (ADLs).Data for 65 consecutive PD patients who underwent both DAT and MIBG imaging were reviewed. Associations between imaging variables and Hoehn and Yahr (HY) staging or self-supportive care ratings were investigated. Univariate and multivariate regression analyses were performed to determine the factors associated with ADLs.After applying the exclusion criteria, 45 patients were analyzed (age, 73.1 ± 9.3 years; 23 males; HY stage 1: n = 12, stage 2: n = 14, stage 3: n = 10, stage 4: n = 5, and stage 5: n = 4; self-supportive care rating-dependent ADLs: n = 29). Dopamine transporter variables were significantly associated with the clinical severity of PD as assessed by HY staging, whereas MIBG variables were not. Dopamine transporter variables gradually decreased throughout progressive stages, whereas the MIBG variables changed only in the advanced stages. In a multivariate analysis including clinical and imaging variables, both lower DAT and MIBG uptakes were significantly associated with dependent ADL status (P = 0.028 and 0.034, respectively).In patients with PD, DAT SPECT and MIBG myocardial scintigraphy were associated with ADL status; DAT SPECT was a stronger indicator of severity than MIBG myocardial scintigraphy in the early and middle stages.

An 123I-MIBG scan was obtained to evaluate a right adrenal mass in a 10-year-old boy, which showed no elevated activity in the lesion. However, diffuse increased activity was noted in the right forearm with typical manifestation of an "arterial injection." Different from a prior case report, no symptoms or signs related to arterial injection were observed in our patient.

We report an unusual case of primary neuroblastoma in an 11-year-old girl. The superior portion of the tumor accumulated I-MIBG, Tc-MDP, and F-FDG. In contrast, the inferior portion of the tumor showed no abnormal F-FDG or Tc-MDP uptake, which usually indicates tumor necrosis. This inferior portion of the tumor, however, had intense I-MIBG activity, consistent with viable tumor rather than tumor necrosis.

A 61-year-old woman diagnosed with a metastatic well-differentiated neuroendocrine tumor of the cecum was referred for radioisotope therapy. Although her metastatic neuroendocrine tumor was positive on both (123)I-MIBG and (111)In-octreotide, there was a left parotid mass that was octreotide avid but MIBG negative. Further investigation also showed discordance on (18)F-FDG PET/CT and excision of the mass revealed an incidental acinic cell carcinoma of the parotid gland. Somatostatin analog imaging and PRRT (peptide receptor radionuclide therapy) may have a role in the management of acinic cell carcinoma.

An 123I metaiodobenzylguanidine (MIBG) planar image showed abnormal uptake in the left adrenal gland and thyroid in a 24-year-old woman with multiple endocrine neoplasia type 2A. 131I MIBG showed abnormal uptake in the thyroid but not in the adrenal gland. Abdominal CT with 2-mm thin slices demonstrated a normal adrenal gland. Postoperative pathologic findings were consistent with medullary carcinoma in both thyroid lobes and a small 1-mm pheochromocytoma in the left adrenal gland. 123I MIBG could clearly show the small pheochromocytoma, which was negative in thin-slice CT and equivocal in 131I MIBG.

We describe a patient with labile hypertension and elevated metanephrines who underwent 123Iodine metaiodobenzylguanidine (MIBG) for the detection of a possible paraganglioma. The scan revealed markedly abnormal diffusely increased activity in the right renal parenchyma. A CT angiogram showed severe renal artery stenosis of an atrophic-appearing right kidney and delayed enhancement of the right kidney, consistent with renal dysfunction due to renal artery stenosis.