International consensus on clinical use of presynaptic dopaminergic positron emission tomography imaging in parkinsonism.

PURPOSE: Presynaptic dopaminergic positron emission tomography (PET) imaging serves as an essential tool in diagnosing and differentiating patients with suspected parkinsonism, including idiopathic Parkinson's disease (PD) and other neurodegenerative and non-neurodegenerative diseases. The PET tracers most commonly used at the present time mainly target dopamine transporters (DAT), aromatic amino acid decarboxylase (AADC), and vesicular monoamine type 2 (VMAT2). However, established standards for the imaging procedure and interpretation of presynaptic dopaminergic PET imaging are still lacking. The goal of this international consensus is to help nuclear medicine practitioners procedurally perform presynaptic dopaminergic PET imaging. METHOD: A multidisciplinary task group formed by experts from various countries discussed and approved the consensus for presynaptic dopaminergic PET imaging in parkinsonism, focusing on standardized recommendations, procedures, interpretation, and reporting. CONCLUSION: This international consensus and practice guideline will help to promote the standardized use of presynaptic dopaminergic PET imaging in parkinsonism. It will become an international standard for this purpose in clinical practice.

Diagnostic performance of [68Ga]DOTATATE PET/CT, [18F]FDG PET/CT, MRI of the spine, and whole-body diagnostic CT and MRI in the detection of spinal bone metastases associated with pheochromocytoma and paraganglioma.

OBJECTIVE: To compare the diagnostic performance of [68Ga]DOTATATE PET/CT, [18F]FDG PET/CT, MRI of the spine, and whole-body CT and MRI for the detection of pheochromocytoma/paraganglioma (PPGL)-related spinal bone metastases. MATERIALS AND METHODS: Between 2014 and 2020, PPGL participants with spinal bone metastases prospectively underwent [68Ga]DOTATATE PET/CT, [18F]FDG PET/CT, MRI of the cervical-thoracolumbar spine (MRIspine), contrast-enhanced MRI of the neck and thoraco-abdominopelvic regions (MRIWB), and contrast-enhanced CT of the neck and thoraco-abdominopelvic regions (CTWB). Per-patient and per-lesion detection rates were calculated. Counting of spinal bone metastases was limited to a maximum of one lesion per vertebrae. A composite of all functional and anatomic imaging served as an imaging comparator. The McNemar test compared detection rates between the scans. Two-sided p values were reported. RESULTS: Forty-three consecutive participants (mean age, 41.7 ± 15.7 years; females, 22) with MRIspine were included who also underwent [68Ga]DOTATATE PET/CT (n = 43), [18F]FDG PET/CT (n = 43), MRIWB (n = 24), and CTWB (n = 33). Forty-one of 43 participants were positive for spinal bone metastases, with 382 lesions on the imaging comparator. [68Ga]DOTATATE PET/CT demonstrated a per-lesion detection rate of 377/382 (98.7%) which was superior compared to [18F]FDG (72.0%, 275/382, p < 0.001), MRIspine (80.6%, 308/382, p < 0.001), MRIWB (55.3%, 136/246, p < 0.001), and CTWB (44.8%, 132/295, p < 0.001). The per-patient detection rate of [68Ga]DOTATATE PET/CT was 41/41 (100%) which was higher compared to [18F]FDG PET/CT (90.2%, 37/41, p = 0.13), MRIspine (97.6%, 40/41, p = 1.00), MRIWB (95.7%, 22/23, p = 1.00), and CTWB (81.8%, 27/33, p = 0.03). CONCLUSIONS: [68Ga]DOTATATE PET/CT should be the modality of choice in PPGL-related spinal bone metastases due to its superior detection rate. CLINICAL RELEVANCE STATEMENT: In a prospective study of 43 pheochromocytoma/paraganglioma participants with spinal bone metastases, [68Ga]DOTATATE PET/CT had a superior per-lesion detection rate of 98.7% (377/382), compared to [18F]FDG PET/CT (p < 0.001), MRI of the spine (p < 0.001), whole-body CT (p < 0.001), and whole-body MRI (p < 0.001). KEY POINTS: • Data regarding head-to-head comparison between functional and anatomic imaging modalities to detect spinal bone metastases in pheochromocytoma/paraganglioma are limited. • [68Ga]DOTATATE PET/CT had a superior per-lesion detection rate of 98.7% in the detection of spinal bone metastases associated with pheochromocytoma/paraganglioma compared to other imaging modalities: [18]F-FDG PET/CT, MRI of the spine, whole-body CT, and whole-body MRI. • [68Ga]DOTATATE PET/CT should be the modality of choice in the evaluation of spinal bone metastases associated with pheochromocytoma/paraganglioma.

International consensus on the use of tau PET imaging agent 18F-flortaucipir in Alzheimer's disease.

PURPOSE: Positron emission tomography (PET) with the first and only tau targeting radiotracer of 18F-flortaucipir approved by FDA has been increasingly used in depicting tau pathology deposition and distribution in patients with cognitive impairment. The goal of this international consensus is to help nuclear medicine practitioners procedurally perform 18F-flortaucipir PET imaging. METHOD: A multidisciplinary task group formed by experts from various countries discussed and approved the consensus for 18F-flortaucipir PET imaging in Alzheimer's disease (AD), focusing on clinical scenarios, patient preparation, and administered activities, as well as image acquisition, processing, interpretation, and reporting. CONCLUSION: This international consensus and practice guideline will help to promote the standardized use of 18F-flortaucipir PET in patients with AD. It will become an international standard for this purpose in clinical practice.

International consensus on the use of [18F]-FDG PET/CT in pediatric patients affected by epilepsy.

PURPOSE: Positron emission tomography (PET) with 18F-fluorodeoxyglucose ([18F]-FDG) has been increasingly applied in precise localization of epileptogenic focus in epilepsy patients, including pediatric patients. The aim of this international consensus is to provide the guideline and specific considerations for [18F]-FDG PET in pediatric patients affected by epilepsy. METHODS: An international, multidisciplinary task group is formed, and the guideline for brain [18F]-FDG PET/CT in pediatric epilepsy patients has been discussed and approved, which include but not limited to the clinical indications, patient preparation, radiopharmaceuticals and administered activities, image acquisition, image processing, image interpretation, documentation and reporting, etc. CONCLUSION: This is the first international consensus and practice guideline for brain [18F]-FDG PET/CT in pediatric epilepsy patients. It will be an international standard for this purpose in clinical practice.

The application of 18F-FDG PET/CT imaging for human hepatocellular carcinoma: a narrative review.

Background and Objective: Primary hepatocellular carcinoma (HCC) poses a significant threat to human health. The mean overall survival (OS) of HCC is approximately 15.8 months whereas the 6-month and 1-year OS rates are only 71.6% and 49.7%, respectively. 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) has been widely used for the management of several solid cancers; however, HCC frequently displays low 18F-FDG uptake; approximately 50% of HCC cases do not take up 18F-FDG. Therefore, 18F-FDG PET is not considered very useful for the visualization of HCC and is not currently a recommended standard imaging modality for HCC. Conversely, 18F-FDG PET/CT has been reported to be clinically important in the management, staging, and prognosis of HCC patients. Currently, reports relating to 18F-FDG uptake in HCC are unclear and controversial. There is an urgent need to clarify the efficacy of 18F-FDG PET for the management of HCC. Methods: The PubMed database was searched for all articles on the application of 18F-FDG PET/CT imaging for human HCC up to December 2021. The following search terms were used: 'Hepatocellular carcinoma', '[18F]FDG PET/CT', 'Hypoxia', '[11C]Choline'. Key Content and Findings: In this review, we re-evaluate the potential hypoxia-dependent uptake mechanism of 18F-FDG in HCC and review the usefulness of 18F-FDG PET/CT for identifying, managing, and investigating the biological properties of HCC. Conclusions: 18F-FDG PET/CT is very useful for HCC visualization, management, and the evaluation of biological properties. A negative test for 18F-FDG uptake is not meaningless and may reflect a relatively better outcome. 18F-FDG-positive lesions indicate a significantly less favorable prognosis.

Likely Common Role of Hypoxia in Driving 18F-FDG Uptake in Cancer, Myocardial Ischemia, Inflammation and Infection.

First introduced in 1976, 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) has become an indispensable tool for diagnosis and prognostic evaluation of tumors, heart disease, as well as other conditions, including inflammation and infection. Because 18F-FDG can accurately reflect the glucose metabolism level of organs and tissues, it is known as a "century molecule" and is currently the main agent for PET imaging. The degree of 18F-FDG uptake by cells is related to both the rate of glucose metabolism and glucose transporter expression. These, in turn, are strongly influenced by hypoxia, in which cells meet their energy needs through glycolysis, and 18F-FDG uptake increased due to hypoxia. 18F-FDG uptake is a complex process, and hypoxia may be one of the fundamental driving forces. The correct interpretation of 18F-FDG uptake in PET imaging can help clinics make treatment decisions more accurately and effectively. In this article, we review the application of 18F-FDG PET in tumors, myocardium, and inflammation. We discuss the relationship between 18F-FDG uptake and hypoxia, the possible mechanism of 18F-FDG uptake caused by hypoxia, and the associated clinical implications.

Median sternotomy for an unexpected complication of permanent hemodialysis catheters: "stuck catheter".

Cuffed tunneled venous access catheters are commonly used for temporary and permanent access in patients undergoing hemodialysis. These catheters play an essential role in providing permanent access in patients in whom all other access options have been exhausted. However, they are prone to several complications like catheter thrombosis, catheter fibrin sheating and infection. Herein, we report two uncommon cases of stuck hemodialysis cuffed tunneled catheters causing stenosis and thrombosis in central veins which needed to be removed by median sternotomy.

Tc-99m sestamibi uptake in the chest mimicking a malignant lesion of the breast.

The use of nuclear medicine imaging of the breast has resulted in the improved diagnosis of breast cancer (Radiology 196 (1995) 421; J. Nucl. Med. 36 (1995) 1758). It's use is becoming more widespread, particularly as breast optimized scintigraphy with a high-resolution, breast-specific gamma camera has been developed (J. Nucl. Med. 43 (2002) 909; J. Nucl. Med. 45 (2004) 553). With the increasing use of breast-optimized scintigraphy, pitfalls in the interpretation of breast-optimized scintigraphy are being recognized. This report describes a previously unrecognized cause for a false positive interpretation of scintimammography due to tumor uptake of the radiotracer in the chest as a result of physiologic activity in the auricular aspect of the right atrium.

Cutaneous metastatic lung cancer detected with 18F-FDG PET.

A 48-year-old male smoker presented with a chief complaint of persistent cough for three months. A CT scan revealed only a large right paratracheal mass. The plan was to obtain histological confirmation of suspected lung cancer via bronchoscopy and mediastinoscopy. A whole body 18F-FDG (2-deoxy-2-[18F]fluoro-D-glucose) PET Scan was ordered for staging and localization of the most accessible biopsy site. There was a large, intense hypermetabolic focus corresponding to the paratracheal lesion seen on CT, as well as a lesion in the right adrenal gland. There was also a superficial, subcutaneous hypermetabolic lesion in the mid-back. The subcutaneous lesion, which previously had not been noted, was biopsied and proved to be metastatic adenocarcinoma consistent with the lung primary. This case illustrates the clinical utility of reporting soft tissue abnormalities, which may provide an alternative, more readily accessible location for biopsy that is both safer and less expensive than bronchoscopy or mediastinoscopy.

Pigmented villonodular synovitis mimics metastases on fluorine 18 fluorodeoxyglucose position emission tomography-computed tomography.

Pigmented villonodular synovitis (PVNS) is a benign joint disease best characterized on magnetic resonance imaging (MRI). The role of fluorine 18 fluorodeoxyglucose ((18)F-FDG) position emission tomography-computed tomography (PET-CT) in the diagnosis or characterization remains unclear. PVNS displays as a focal FDG avid lesion, which can masquerade as a metastatic lesion, on PET-CET. We present a case of PVNS found on surveillance imaging of a lymphoma patient.

Interpretation of 99mTc sestamibi parathyroid SPECT scan is improved when read by the surgeon and nuclear medicine physician together.

OBJECTIVE: Parathyroid gland localization and lateralization are important before surgery, particularly for minimally invasive parathyroidectomy (MIP) and recurrent hyperparathyroidism. We hypothesized that readings of Tc sestamibi scans with single photon emission computed tomography (SPECT) by a surgeon and nuclear medicine physician together (NMP+S) compared to a nuclear medicine physician alone (NMP alone) might affect scan interpretation accuracy. METHODS: Between May 1999 and December 2002, 127 hyperparathyroid patients had preoperative localization with sestamibi SPECT. Scans were prospectively interpreted by an endocrine surgeon and nuclear medicine physician attending together (NMP+S) and a nuclear medicine physician attending alone (NMP alone). These readings were compared to intra-operative findings, which served as the 'gold standard'. RESULTS: There were 120 patients with primary hyperparathyroidism (55 underwent MIP) and seven with secondary or tertiary hyperparathyroidism; seven patients had recurrent hyperparathyroidism. Of 127 patients, 83 had single adenomas; 27, double adenomas; 15, hyperplasia; one, MENIIA; and one, parathyroid cancer. Sensitivity and positive predictive values were 58.6% and 67.4% for NMP alone compared to 81.9% and 70.0% for NMP+S. The overall accuracy of correct localization was 45.7% vs. 60.6% (P<0.01) and of correct lateralization was 69.3% vs. 80.3% (P<0.01) for NMP alone versus NMP+S respectively. The most common finding interpreted incorrectly by NMP alone and correctly by NMP+S was an ectopic superior parathyroid adenoma in the inferior position. Ninety-eight per cent of patients were cured of their hyperparathyroidism. CONCLUSIONS: Parathyroid sestamibi SPECT scan interpretation by an endocrine surgeon reading with a nuclear medicine attending resulted in improved accuracy of gland localization and lateralization compared to a nuclear medicine attending reading alone. This improvement may be due to increased awareness of clinical factors and head-and-neck anatomy.

Longer occupancy of opioid receptors by nalmefene compared to naloxone as measured in vivo by a dual-detector system.

UNLABELLED: Surgical procedures usually involve the administration of narcotic drugs as anesthetics or adjuvants. To reverse the effects of anesthesia, opioid antagonists such as naloxone are commonly used. Due to its short lasting effects, patients receiving naloxone must be monitored carefully. Nalmefene, a pure opiate antagonist with a longer duration of action than naloxone, has shown promise in the reversal of opioid anesthesia. METHODS: A simple dual-detector positron radiation detector system and [11C]carfentanil were used to compare the duration of blockade of cerebral mu opioid receptors by naloxone and nalmefene in eight normal volunteers. Carbon-11-carfentanil brain kinetics were monitored for 5 min and 2, 4, 8 and 24 hr after the administration of either nalmefene (1 mg or 1 microg/kg) or naloxone (2 mg or 2 microg/kg). Blood samples were obtained at the same times for plasma determinations. RESULTS: Clearance half-times from opioid receptors were 28.7 +/- 5.9 hr for 1 mg of nalmefene and 2.0 +/- 1.6 hr for 2 mg of naloxone. Brain clearance times were about 21.1 and 3.4 times slower than plasma clearance times for nalmefene and naloxone, respectively. CONCLUSION: These findings suggest that the prolonged effects of nalmefene are related to the slow dissociation of nalmefene from opioid receptors, which are not reflected in the plasma curve. This longer blockade of opioid receptors by nalmefene represents an advantage in the clinical management of postsurgical reversal of narcotic anesthesia and opioid side effects as well as the reversal of opioid overdose.

Circumferential wall thickness measurements of the human left ventricle: reference data for thallium-201 single-photon emission computed tomography.

New heart imaging methods, including echocardiography, single-photon emission computed tomography (SPECT) and nuclear magnetic resonance, involve measurements of left ventricular (LV) wall thickness in cross sections perpendicular to the LV long axis. To provide a reference base, LV myocardial wall thicknesses were measured in human autopsy specimens. Short-axis views were chosen at the base of the heart, at the level of the papillary muscles and at a level close to the apex. At the 3 levels, LV wall thicknesses were measured for each of 36 circumferential sectors. The measurements revealed a nonuniformity of LV myocardial wall thickness, related to the papillary muscles, the anterior and posterior junctions with the right ventricle and the thinness of the ventricular septum. These findings help to explain the structured appearance of SPECT 201-thallium short-axis views.

Predictors of left atrial thrombus and spontaneous echo contrast in rheumatic valve disease before and after mitral valve replacement.

In this study we aimed to analyze, with reference to mitral regurgitation (MR), the incidence and predictors of left atrial (LA) thrombus and spontaneous echo contrast in patients with rheumatic valve disease before and after mitral valve replacement. The incidence of LA thrombus is known to be less in patients with MR. The impact of mitral valve replacement on this beneficial effect has not been studied in detail. The study included 169 consecutive patients (59 men and 110 women, average age 40 +/- 13 years) with rheumatic mitral valve disease who underwent transesophageal echocardiographic examination 1 to 3 days before and within 7 days (mean 4.0 +/- 1.3) after mitral valve replacement using mechanical prostheses in a single institution. The preoperative incidence of echocardiographic LA spontaneous echo contrast (SEC) was 1.1%, 30%, and 54%, and the incidence of thrombus was 1.1%, 13%, and 17% in the groups with MR, combined mitral stenosis + MR, and isolated mitral stenosis, respectively. In the MR group, SEC and thrombus incidence increased significantly after surgery. The independent predictors for postoperative thrombus development were atrial fibrillation, postoperative SEC, and preoperative thrombus. Thrombus recurred after surgery in 64% of 14 patients who had surgical thrombectomy. The presence of postoperative MR was associated with decreased risk of postoperative SEC and thrombus development. The interaction between MR and SEC and thrombus both before and after surgery provides further support for the protective effect of MR against LA thrombus formation.

Detection of left anterior descending coronary artery disease in patients with left bundle branch block.

The detection of coronary artery disease is difficult if a patient has electrocardiographic evidence of left bundle branch block (BBB). Septal blood flow may be reduced in patients with left BBB, despite no angiographic evidence of left anterior descending (LAD) coronary artery disease. We have developed a new method of quantification of Thallium-201 single-photon emission computed tomographic (SPECT) images with the aim of better separating patients with left BBB and LAD disease from those with left BBB alone. The study cohort comprised 8 normal subjects (group I) and 20 patients with left BBB and chest pain who underwent thallium-201 SPECT imaging and coronary angiography. Eight patients (group II) had < or = 50% LAD stenosis, and 12 (group III) had > or = 70% LAD stenosis. Septal abnormality scores on the second short-axis slice from the base were computed, based on comparison of each subject's short-axis circumferential profile with a normal reference curve. This followed a procedure in which each profile was scaled to minimize differences in its absolute level in relation to the reference curve. Septal abnormality scores on stress images were 0.8 +/- 22 for group I, 27 +/- 43 for group II, and 165 +/- 67 for group III (p = 0.15 for group I vs II, and p < 0.0001 between groups I and III, and II and III).(ABSTRACT TRUNCATED AT 250 WORDS)