Summary: Appropriate Use Criteria for Lymphoscintigraphy in Sentinel Node Mapping and Lymphedema/Lipedema.

Expert representatives from 11 professional societies, as part of an autonomous work group, researched and developed appropriate use criteria (AUC) for lymphoscintigraphy in sentinel lymph node mapping and lymphedema. The complete findings and discussions of the work group, including example clinical scenarios, were published on October 8, 2022, and are available at https://www.snmmi.org/ClinicalPractice/content.aspx?ItemNumber=42021 The complete AUC document includes clinical scenarios for scintigraphy in patients with breast, cutaneous, and other cancers, as well as for mapping lymphatic flow in lymphedema. Pediatric considerations are addressed. These AUC are intended to assist health care practitioners considering lymphoscintigraphy. Presented here is a brief overview of the AUC, including the rationale and methodology behind development of the document. For detailed findings of the work group, the reader should refer to the complete AUC document online.

MRI staging of upper extremity secondary lymphedema: correlation with clinical measurements.

OBJECTIVES: Staging of upper extremity lymphedema is needed to guide surgical management, but is not standardized due to lack of accessible, quantitative, or precise measures. Here, we established an MRI-based staging system for lymphedema and validate it against existing clinical measures. METHODS: Bilateral upper extremity MRI and lymphoscintigraphy were performed on 45 patients with unilateral secondary lymphedema, due to surgical intervention, who were referred to our multidisciplinary lymphedema clinic between March 2017 and October 2018. MRI short-tau inversion recovery (STIR) images were retrospectively reviewed. A grading system was established based on the cross-sectional circumferential extent of subcutaneous fluid infiltration at three locations, labeled MRI stage 0-3, and was compared to L-Dex®, ICG lymphography, volume, lymphedema quality of life (LYMQOL), International Society of Lymphology (ISL) stage, and lymphoscintigraphy. Linear weighted Cohen's kappa was calculated to compare MRI staging by two readers. RESULTS: STIR images on MRI revealed a predictable pattern of fluid infiltration centered on the elbow and extending along the posterior aspect of the upper arm and the ulnar side of the forearm. Patients with higher MRI stage were more likely to be in ISL stage 2 (p = 0.002) or to demonstrate dermal backflow on lymphoscintigraphy (p = 0.0002). No correlation was found between MRI stages and LYMQOL. Higher MRI stage correlated with abnormal ICG lymphography pattern (rs = 0.63, p < 0.0001), larger % difference in limb volume (rs = 0.68, p < 0.0001), and higher L-Dex® ratio (rs = 0.84, p < 0.0001). Cohen's kappa was 0.92 (95% CI, 0.85-1.00). CONCLUSION: An MRI staging system for upper extremity lymphedema offers an improved non-invasive precision marker for lymphedema for therapeutic planning. KEY POINTS: • Diagnosis and staging of patients with secondary upper extremity lymphedema may be performed with non-contrast MRI, which is non-invasive and more readily accessible compared to lymphoscintigraphy and evaluation by lymphedema specialists. • MRI-based staging of secondary upper extremity lymphedema is highly reproducible and could be used for long-term follow-up of patients. • In patients with borderline clinical measurements, MRI can be used to identify patients with early-stage lymphedema.

Developing a Lymphatic Surgery Program: A First-Year Review.

BACKGROUND: Lymphedema is a chronic condition that carries a significant physical, psychosocial, and economic burden. The authors' program was established in 2017 with the aims of providing immediate lymphatic reconstruction in high-risk patients undergoing lymphadenectomy and performing delayed lymphatic reconstruction in patients with chronic lymphedema. The purpose of this study was to describe the authors' clinical experience in the first year. METHODS: A retrospective review of our clinical database was performed on all individuals presenting to the authors' institution for lymphatic surgery consideration. Patient demographics, clinical characteristics, and surgical management were reviewed. RESULTS: A total of 142 patients presented for lymphatic surgery evaluation. Patients had a mean age of 54.8 years and an average body mass index of 30.4 kg/m. Patients with lymphedema were more likely to be referred from an outside facility compared to patients seeking immediate lymphatic reconstruction (p < 0.001). For patients with lymphedema, the most common cause was breast cancer related. Thirty-two percent of all patients evaluated underwent a lymphatic procedure. Of these, 32 were immediate lymphatic reconstructions and 13 were delayed lymphatic reconstructions. In the authors' first year, 94 percent of eligible patients presenting for immediate lymphatic reconstruction underwent an intervention versus only 38 percent of eligible lymphedema patients presenting for delayed lymphatic reconstruction (p < 0.001). CONCLUSIONS: First-year review of our lymphatic surgery experience has demonstrated clinical need evidenced by the number of patients and high percentage of outside referrals. As a program develops, lymphatic surgeons should expect to perform more time-sensitive immediate lymphatic reconstructions, as evaluation of chronic lymphedema requires development of a robust team for workup and review.

FDG PET/CT: EANM procedure guidelines for tumour imaging: version 2.0.

The purpose of these guidelines is to assist physicians in recommending, performing, interpreting and reporting the results of FDG PET/CT for oncological imaging of adult patients. PET is a quantitative imaging technique and therefore requires a common quality control (QC)/quality assurance (QA) procedure to maintain the accuracy and precision of quantitation. Repeatability and reproducibility are two essential requirements for any quantitative measurement and/or imaging biomarker. Repeatability relates to the uncertainty in obtaining the same result in the same patient when he or she is examined more than once on the same system. However, imaging biomarkers should also have adequate reproducibility, i.e. the ability to yield the same result in the same patient when that patient is examined on different systems and at different imaging sites. Adequate repeatability and reproducibility are essential for the clinical management of patients and the use of FDG PET/CT within multicentre trials. A common standardised imaging procedure will help promote the appropriate use of FDG PET/CT imaging and increase the value of publications and, therefore, their contribution to evidence-based medicine. Moreover, consistency in numerical values between platforms and institutes that acquire the data will potentially enhance the role of semiquantitative and quantitative image interpretation. Precision and accuracy are additionally important as FDG PET/CT is used to evaluate tumour response as well as for diagnosis, prognosis and staging. Therefore both the previous and these new guidelines specifically aim to achieve standardised uptake value harmonisation in multicentre settings.

Sources of apical defects on a high-sensitivity cardiac camera: experiences from a practice performance assessment.

UNLABELLED: Apical perfusion artifacts seen on a high-sensitivity camera warranted a practice performance assessment to evaluate contributions from soft-tissue attenuation, patient positioning, and image processing techniques. METHODS: Cardiac perfusion studies (n = 534) spanning 5 mo were retrospectively reviewed. Images were acquired with the patient in the upright position, and attenuation correction was used. Regression analysis and contingency tables correlated clinical data to the presence of apical artifacts. RESULTS: There was a positive correlation of with female sex (χ(2) = 32, P < 0.001), degree of overlying soft tissues (χ(2) = 20, P < 0.002), and breast cleavage (χ(2) = 7, P < 0.008) and a negative correlation with angiography-confirmed disease (χ(2) = 6, P < 0.02). There was moderate interobserver agreement between 2 observers in determining the presence of apical defects (κ= 0.44, 95% confidence interval = 0.19-0.69), and there was a perceived improvement of apical defects using fewer iterative updates (χ(2) = 8, P < 0.003). CONCLUSION: An understanding of sources contributing to imaging artifacts is a crucial portion of quality assessment in radiology and nuclear medicine. A practice performance assessment study at our institution showed that apical artifacts on a new-generation cardiac camera can be partially attributed to overlying soft-tissue attenuation and ameliorated by altering the reconstruction.

Update on appropriate use criteria for amyloid PET imaging: dementia experts, mild cognitive impairment, and education. Amyloid Imaging Task Force of the Alzheimer's Association and Society for Nuclear Medicine and Molecular Imaging.

Amyloid PET imaging is a novel diagnostic test that can detect in living humans one of the two defining pathologic lesions of Alzheimer disease, amyloid-ß deposition in the brain. The Amyloid Imaging Task Force of the Alzheimer's Association and Society for Nuclear Medicine and Molecular Imaging previously published appropriate use criteria for amyloid PET as an important tool for increasing the certainty of a diagnosis of Alzheimer disease in specific patient populations. Here, the task force further clarifies and expands 3 topics discussed in the original paper: first, defining dementia experts and their use of proper documentation to demonstrate the medical necessity of an amyloid PET scan; second, identifying a specific subset of individuals with mild cognitive impairment for whom an amyloid PET scan is appropriate; and finally, developing educational programs to increase awareness of the amyloid PET appropriate use criteria and providing instructions on how this test should be used in the clinical decision-making process.

Update on appropriate use criteria for amyloid PET imaging: dementia experts, mild cognitive impairment, and education.

Amyloid PET imaging is a novel diagnostic test that can detect in living humans one of the two defining pathologic lesions of Alzheimer disease, amyloid-ß deposition in the brain. The Amyloid Imaging Task Force of the Alzheimer's Association and Society for Nuclear Medicine and Molecular Imaging previously published appropriate use criteria for amyloid PET as an important tool for increasing the certainty of a diagnosis of Alzheimer disease in specific patient populations. Here, the task force further clarifies and expands 3 topics discussed in the original paper: first, defining dementia experts and their use of proper documentation to demonstrate the medical necessity of an amyloid PET scan; second, identifying a specific subset of individuals with mild cognitive impairment for whom an amyloid PET scan is appropriate; and finally, developing educational programs to increase awareness of the amyloid PET appropriate use criteria and providing instructions on how this test should be used in the clinical decision-making process.

Appropriate use criteria for amyloid PET: a report of the Amyloid Imaging Task Force, the Society of Nuclear Medicine and Molecular Imaging, and the Alzheimer's Association.

Positron emission tomography (PET) of brain amyloid ß is a technology that is becoming more available, but its clinical utility in medical practice requires careful definition. To provide guidance to dementia care practitioners, patients, and caregivers, the Alzheimer's Association and the Society of Nuclear Medicine and Molecular Imaging convened the Amyloid Imaging Taskforce (AIT). The AIT considered a broad range of specific clinical scenarios in which amyloid PET could potentially be used appropriately. Peer-reviewed, published literature was searched to ascertain available evidence relevant to these scenarios, and the AIT developed a consensus of expert opinion. Although empirical evidence of impact on clinical outcomes is not yet available, a set of specific appropriate use criteria (AUC) were agreed on that define the types of patients and clinical circumstances in which amyloid PET could be used. Both appropriate and inappropriate uses were considered and formulated, and are reported and discussed here. Because both dementia care and amyloid PET technology are in active development, these AUC will require periodic reassessment. Future research directions are also outlined, including diagnostic utility and patient-centered outcomes.

Appropriate use criteria for amyloid PET: a report of the Amyloid Imaging Task Force, the Society of Nuclear Medicine and Molecular Imaging, and the Alzheimer's Association.

Positron emission tomography (PET) of brain amyloid b is a technology that is becoming more available, but its clinical utility in medical practice requires careful definition. To provide guidance to dementia care practitioners, patients, and caregivers, the Alzheimer's Association and the Society of Nuclear Medicine and Molecular Imaging convened the Amyloid Imaging Taskforce (AIT). The AIT considered a broad range of specific clinical scenarios in which amyloid PET could potentially be used appropriately. Peer-reviewed, published literature was searched to ascertain available evidence relevant to these scenarios, and the AIT developed a consensus of expert opinion. Although empirical evidence of impact on clinical outcomes is not yet available, a set of specific appropriate use criteria (AUC) were agreed on that define the types of patients and clinical circumstances in which amyloid PET could be used. Both appropriate and inappropriate uses were considered and formulated,and are reported and discussed here. Because both dementia care and amyloid PET technology are in active development, these AUC will require periodic reassessment. Future research directions are also outlined, including diagnostic utility and patient-centered outcomes.

Evaluation of relative renal function for patients who had undergone simultaneous liver-kidney transplants using Tc-99m-MAG3 scintigraphy with attenuation correction from anatomical images and SPECT/CT.

OBJECTIVE: Assessing the relative function of each of the three kidneys using nuclear scintigraphy with standard planar imaging in patients having undergone kidney transplant is problematic because of the different photon-attenuation factors associated with native versus transplanted kidneys. To address this, we applied a correction for the attenuation of 140-keV photons based on measurements taken on cross-sectional anatomical images. We performed a validation of the method using single-photon emission computed tomography/computed tomography (SPECT/CT). METHODS: Abdominal CT scans of 13 patients who had undergone simultaneous liver-kidney transplants were examined for kidney depth. Ten of those patients had undergone Tc-99m-mercaptoacetyltriglycine (MAG3) renal scans, using a Philips Precedence SPECT/CT scanner by which abdominal CT and renal SPECT acquisition followed the planar scintigraphic renogram. Kidney depth at the level of the renal hilum was measured on the concurrently acquired CT images, and it was used to derive an attenuation correction factor (ACF) that was applied to the background-subtracted activity in the planar scintigraphic renogram. RESULTS: ACFs calculated from kidney depths ranged from 1.31 to 4.33. The ratio of ACFs for transplant to native kidneys ranged from 0.63 to 1.51, with an average of 0.90. Applying attenuation correction when calculating relative function increased the value of native kidney function by as much as 40%. CONCLUSION: Attenuation correction through measurements taken on anatomical images, preferably obtained concurrently using a hybrid SPECT/CT scanner, should improve the accuracy of functional measurements in renal scintigraphy. This improved accuracy is clinically important in assessing the relative function of native and transplant kidneys in recipients of simultaneous liver-kidney transplants.

Toward optimization of imaging system and lymphatic tracer for near-infrared fluorescent sentinel lymph node mapping in breast cancer.

BACKGROUND: Near-infrared (NIR) fluorescent sentinel lymph node (SLN) mapping in breast cancer requires optimized imaging systems and lymphatic tracers. MATERIALS AND METHODS: A small, portable version of the FLARE imaging system, termed Mini-FLARE, was developed for capturing color video and two semi-independent channels of NIR fluorescence (700 and 800 nm) in real time. Initial optimization of lymphatic tracer dose was performed using 35-kg Yorkshire pigs and a 6-patient pilot clinical trial. More refined optimization was performed in 24 consecutive breast cancer patients. All patients received the standard of care using (99m)Technetium-nanocolloid and patent blue. In addition, 1.6 ml of indocyanine green adsorbed to human serum albumin (ICG:HSA) was injected directly after patent blue at the same location. Patients were allocated to 1 of 8 escalating ICG:HSA concentration groups from 50 to 1000 µM. RESULTS: The Mini-FLARE system was positioned easily in the operating room and could be used up to 13 in. from the patient. Mini-FLARE enabled visualization of lymphatic channels and SLNs in all patients. A total of 35 SLNs (mean = 1.45, range 1-3) were detected: 35 radioactive (100%), 30 blue (86%), and 35 NIR fluorescent (100%). Contrast agent quenching at the injection site and dilution within lymphatic channels were major contributors to signal strength of the SLN. Optimal injection dose of ICG:HSA ranged between 400 and 800 µM. No adverse reactions were observed. CONCLUSIONS: We describe the clinical translation of a new NIR fluorescence imaging system and define the optimal ICG:HSA dose range for SLN mapping in breast cancer.