The American College of Nuclear Medicine Guidance on Operating Procedures for a Nuclear Medicine Facility During COVID-19 Pandemic

SPECT Ventilation/Perfusion Imaging for Acute Pulmonary Embolism: Meta-analysis of Diagnostic Test Accuracy

RATIONALE AND OBJECTIVES

This study aimed to evaluate the diagnostic accuracies of ventilation/perfusion-single photon emission computed tomography (V/Q-SPECT) imaging modalities for acute pulmonary embolism (PE). These included, in addition to V/Q-SPECT, V/Q-SPECT with low-dose computed tomography (CT; V/Q-SPECT-CT), Q-SPECT with low-dose CT (Q-SPECT-CT), and Q-SPECT.

MATERIALS AND METHODS

PubMed, Embase, CINAHL, and Web of Science databases were searched, and studies included if they studied ≥10 adult participants with acute PE and reported data on the imaging tests' diagnostic performance. Data were meta-analyzed using bivariate random effects regression model.

RESULTS

Data from participants totaling 4146 from 11 V/Q-SPECT studies, 785 from 7 V/Q-SPECT-CT studies, 1196 from 7 Q-SPECT-CT studies, and 728 from five Q-SPECT studies were separately meta-analyzed. The bivariate weighted mean sensitivity and specificity were 0.94 (95% confidence interval [CI]: 0.88-0.97) and 0.95 (95% CI: 0.87-0.98) for V/Q-SPECT, 0.95 (95% CI: 0.88-0.98) and 0.99 (95% CI: 0.92-1.00) for V/Q-SPECT-CT, 0.92 (95% CI: 0.79-0.97) and 0.92 (95% CI: 0.83-0.96) for Q-SPECT-CT, and 0.89 (95% CI: 0.76-0.95) and 0.86 (95% CI: 0.67-0.95) for Q-SPECT studies. The positive and negative likelihood ratios (+LRs and -LRs) were 17.4 (6.9-44.0) and 0.06 (0.03-0.13), 76.7 (11.8-498.0) and 0.06 (0.02-0.13), 11.0 (5.3-22.9) and 0.09 (0.04-0.23), and 6.4 (2.6-15.8) and 0.13 (0.07-0.27) for V/Q-SPECT, V/Q-SPECT-CT, Q-SPECT-CT, and Q-SPECTs, respectively.

CONCLUSION

In the diagnosis of acute PE, this meta-analysis showed that V/Q-SPECT-CT had the highest specificity and +LR. Conversely, Q-SPECT showed the lowest specificity and an unfavorably high -LR.

COVID-19: Findings in nuclear medicine from head to toe

COVID-19 is a multisystemic disease, and hence its potential manifestations on nuclear medicine imaging can extend beyond the lung. Therefore, it is important for the nuclear medicine physician to recognize these manifestations in the clinic. While FDG-PET/CT is not indicated routinely in COVID-19 evaluation, its unique capability to provide a functional and anatomical assessment of the entire body means that it can be a powerful tool to monitor acute, subacute, and long-term effects of COVID-19. Single-photon scintigraphy is routinely used to assess conditions such as pulmonary embolism, cardiac ischemia, and thyroiditis, and COVID-19 may present in these studies. The most common nuclear imaging finding of COVID-19 vaccination to date is hypermetabolic axillary lymphadenopathy. This may pose important diagnostic and management dilemmas in oncologic patients, particularly those with malignancies where the axilla constitutes a lymphatic drainage area. This article aims to summarize the relevant literature published since the beginning of the pandemic on the intersection between COVID-19 and nuclear medicine.

Ventilation Scintigraphy With Radiolabeled Carbon Nanoparticulate Aerosol (Technegas): State-of-the-Art Review and Diagnostic Applications to Pulmonary Embolism During COVID-19 Pandemic

ABSTRACT

Invented and first approved for clinical use in Australia 36 years ago, Technegas is the technology that enabled ventilation scintigraphy with 99m Tc-labeled carbon nanoparticles ( 99m Tc-CNP). The US Food and Drug Administration (FDA) has considered this technology for more than 30 years but only now is getting close to approving it. Meanwhile, more than 4.4 million patients benefited from this technology in 64 countries worldwide. The primary application of 99m Tc-CNP ventilation imaging is the diagnostic evaluation for suspicion of pulmonary embolism using ventilation-perfusion quotient (V/Q) imaging. Because of 99m Tc-CNP's long pulmonary residence, tomographic imaging emerged as the preferred V/Q methodology. The FDA-approved ventilation imaging agents are primarily suitable for planar imaging, which is less sensitive. After the FDA approval of Technegas, the US practice will likely shift to tomographic V/Q. The 99m Tc-CNP use is of particular interest in the COVID-19 pandemic because it offers an option of a dry radioaerosol that takes approximately only 3 to 5 tidal breaths, allowing the shortest exposure to and contact with possibly infected patients. Indeed, countries where 99m Tc-CNP was approved for clinical use continued using it throughout the COVID-19 pandemic without known negative viral transmission consequences. Conversely, the ventilation imaging was halted in most US facilities from the beginning of the pandemic. This review is intended to familiarize the US clinical nuclear medicine community with the basic science of 99m Tc-CNP ventilation imaging and its clinical applications, including common artifacts and interpretation criteria for tomographic V/Q imaging for pulmonary embolism.

Safe Pulmonary Scintigraphy in the Era of COVID-19

One of the major effects of the COVID-19 pandemic within nuclear medicine was to halt performance of lung ventilation studies, due to concern regarding spread of contaminated secretions into the ambient air. A number of variant protocols for performing lung scintigraphy emerged in the medical literature which minimized or eliminated the ventilation component, due to the persistent need to provide this critical diagnostic service without compromising the safety of staff and patients. We have summarized and reviewed these protocols, many of which are based on concepts developed earlier in the history of lung scintigraphy. It is possible that some of these interim remedies may gain traction and earn a more permanent place in the ongoing practice of nuclear medicine.

Impact of COVID-19 pandemic on 2-[18F]FDG PET/CT imaging work-flow in a single medical institution: comparison among the three Italian waves

PURPOSE

To compare the impact of COVID-19 pandemic on 2-[18F]FDG PET/CT imaging work-flow during the three waves in a medical institution of southern of Italy.

METHODS

We retrospectively reviewed the numbers and results of 2-[18F]FDG PET/CT studies acquired during the following three periods of the COVID-19 waves: 1) February 3-April 30, 2020; 2) October 15, 2020-January 15, 2021; and 3) January 18-April 16, 2021.

RESULTS

A total of 861 PET/CT studies in 725 patients (388 men, mean age 64 ± 4 years) was acquired during the three waves of COVID-19 pandemic. The majority (94%) was performed for diagnosis/staging (n = 300) or follow-up (n = 512) of neoplastic diseases. The remaining 49 studies (6%) were acquired for non-oncological patients. The distribution of number and type of clinical indications for PET/CT studies in the three waves were comparable (p = 0.06). Conversely, the occurrence of patients positive for COVID-19 infection progressively increased (p < 0.0001) from the first to third wave; in particular, patients with COVID-19 had active infection before PET/CT study as confirmed by molecular oro/nasopharyngeal swab.

CONCLUSION

Despite the restrictive medical measures for the emergency, the number of 2-[18F]FDG PET/CT studies was unchanged during the three waves guaranteeing the diagnostic performance of PET/CT imaging for oncological patients.

The Impact of COVID-19 on Nuclear Medicine Operations Including Cardiovascular Manifestations in the USA

The pandemic of coronavirus 2019 disease (COVID-19) not only directly causes high morbidity and mortality of the disease, but also indirectly affects patients with pre-existing medical conditions, particularly cardiovascular diseases, with delayed or deferred outpatient care and procedure including nuclear medicine studies because of concerns about exposure to the virus. In this article, the impact of COVID-19 on hospital operation and nuclear medicine practice in the United States along with recommendations and guidance from major academic organizations are presented. Safe operation of specific nuclear medicine scans, such as lung scintigraphy and nuclear cardiac imaging, are reviewed in the context of balancing benefits to patients against the risk of exacerbating the spread of the virus. Thoughtful reintroduction of nuclear medicine services are discussed based on ethical considerations that maximize benefits to those who are likely to benefit most, taking into consideration baseline health inequities, and ensuring that all decisions reflect best available evidence with transparent communication. Finally, potential correlation between decreased volume of nuclear cardiac studies performed during the pandemic and corresponding increased deaths from ischemic and hypertensive cardiac disease is discussed.

Lung scintigraphy for pulmonary embolism diagnosis in COVID-19 patients: a multicenter study

In patients with novel coronavirus disease 2019 (COVID-19) referred for lung scintigraphy for suspected pulmonary embolism (PE), there has been an ongoing debate within the nuclear medicine community as to whether and when the ventilation study should be performed. Indeed, while PE diagnosis typically relies on the recognition of ventilation/perfusion (V/P) mismatched defects, the ventilation procedure potentially increases the risk of contamination to the healthcare workers. The primary aim of this study was to assess the role of ventilation imaging when performing lung scintigraphy for suspected PE in COVID-19 patients. The secondary aim was to describe practices and imaging findings in this specific population. Methods: A national registry was created in collaboration with the French Society of Nuclear Medicine to collect lung scans performed in COVID-19 patients for suspected PE. Practices of departments were assessed regarding imaging protocols and aerosol precautions. A retrospective review of V/P SPECT/CT scans was then conducted. Two physicians blinded to clinical information reviewed each case by sequentially using P SPECT, P SPECT/CT and V/P SPECT/CT images. Scans were classified in one of the four following categories: patients for whom PE could reasonably be excluded based on 1) perfusion SPECT only, 2) P SPECT/CT, 3) V/P SPECT/CT; or 4) patients with mismatched defects suggestive of PE according to the EANM criteria. Results: Data from 12 French nuclear medicine departments were collected. Lung scans were performed between 03/2020 and 04/2021. Personal protective equipment and dedicated cleaning procedures were used in all departments. Out of the 145 V/Q SPECT/CT included in the central review, PE could be excluded using only P SPECT, P SPECT/CT and V/P SPECT/CT in 27 (19%), 55 (38%) and 45 (31%) patients, respectively. V/P SPECT/CT was positive for PE in 18 (12%) patients, including 12 (67%) with a low burden of PE (≤10%). Conclusion: In this population of COVID-19 patients assessed with lung scintigraphy, PE could be confidently excluded without ventilation in only 57% of patients. Ventilation imaging was required to confidently rule out PE in 31% of patients. Overall, the prevalence of PE was low (12%).

State of the art of 18F-FDG PET/CT application in inflammation and infection: a guide for image acquisition and interpretation

AIM

The diagnosis, severity and extent of a sterile inflammation or a septic infection could be challenging since there is not one single test able to achieve an accurate diagnosis. The clinical use of 18F-fluorodeoxyglucose ([18F]FDG) positron emission tomography/computed tomography (PET/CT) imaging in the assessment of inflammation and infection is increasing worldwide. The purpose of this paper is to achieve an Italian consensus document on [18F]FDG PET/CT or PET/MRI in inflammatory and infectious diseases, such as osteomyelitis (OM), prosthetic joint infections (PJI), infective endocarditis (IE), prosthetic valve endocarditis (PVE), cardiac implantable electronic device infections (CIEDI), systemic and cardiac sarcoidosis (SS/CS), diabetic foot (DF), fungal infections (FI), tuberculosis (TBC), fever and inflammation of unknown origin (FUO/IUO), pediatric infections (PI), inflammatory bowel diseases (IBD), spine infections (SI), vascular graft infections (VGI), large vessel vasculitis (LVV), retroperitoneal fibrosis (RF) and COVID-19 infections.

METHODS

In September 2020, the inflammatory and infectious diseases focus group (IIFG) of the Italian Association of Nuclear Medicine (AIMN) proposed to realize a procedural paper about the clinical applications of [18F]FDG PET/CT or PET/MRI in inflammatory and infectious diseases. The project was carried out thanks to the collaboration of 13 Italian nuclear medicine centers, with a consolidate experience in this field. With the endorsement of AIMN, IIFG contacted each center, and the pediatric diseases focus group (PDFC). IIFG provided for each team involved, a draft with essential information regarding the execution of [18F]FDG PET/CT or PET/MRI scan (i.e., indications, patient preparation, standard or specific acquisition modalities, interpretation criteria, reporting methods, pitfalls and artifacts), by limiting the literature research to the last 20 years. Moreover, some clinical cases were required from each center, to underline the teaching points. Time for the collection of each report was from October to December 2020.

RESULTS

Overall, we summarized 291 scientific papers and guidelines published between 1998 and 2021. Papers were divided in several sub-topics and summarized in the following paragraphs: clinical indications, image interpretation criteria, future perspectivess and new trends (for each single disease), while patient preparation, image acquisition, possible pitfalls and reporting modalities were described afterwards. Moreover, a specific section was dedicated to pediatric and PET/MRI indications. A collection of images was described for each indication.

CONCLUSIONS

Currently, [18F]FDG PET/CT in oncology is globally accepted and standardized in main diagnostic algorithms for neoplasms. In recent years, the ever-closer collaboration among different European associations has tried to overcome the absence of a standardization also in the field of inflammation and infections. The collaboration of several nuclear medicine centers with a long experience in this field, as well as among different AIMN focus groups represents a further attempt in this direction. We hope that this document will be the basis for a "common nuclear physicians' language" throughout all the country.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s40336-021-00445-w.

Lymphoscintigraphy in the Time of COVID-19: Effect of Molybdenum-99 Shortage on Feasibility of Sentinel Node Mapping

Background: In the current study, we reported our experience on sentinel node mapping of breast cancer patients during the extreme shortage of Mo99-Tc99m generators using Tc-99m phytate. Methods and Results: During the period from March 7, 2019, to April 18, 2020, due to disruption of molybdenum supply chain, we used low specific activity Tc-99m pertechnetate elute (0.5-2 mCi of 99mTcO4 in 5 mL) for each kit preparation. Two or three intradermal periareolar injections were done for each patient (0.02-0.1 mCi/0.2 mL for each injection). Immediately following injection, dynamic lymphoscintigraphy was done. Surgery was done the same day of injection and the axillary sentinel node was sought using a gamma probe. Overall, 35 patients were included in the study. The specific activity of the Tc-99m elute (in 5 mL) used for kit preparation was 2 mCi/10 mg in four, 1.5 mCi/10 mg in eight, 1.25 mCi/10 mg in eight, 1 mCi/10 mg in three, 0.75 mCi/10 mg in five, and 0.5 mCi/10 mg of 99mTc-Phytate in seven patients. For the first four groups of patients, we used two 0.2 mL injections, while in the latter two groups, three 0.2 mL injections were used. At least one sentinel node was detected in all patients but three in whom axilla was involved. Conclusion: Sentinel node biopsy can be achieved with low specific activity of Tc-99m elute at the time of Mo99-Tc-99m generator shortage. If special personal protection is used, sentinel node mapping can be done in nuclear medicine departments with excellent results despite the COVID-19 pandemic and disruption of generator shipment.

Asymptomatic COVID-19 cancer patients incidentally discovered during F18-FDG PET/CT monitoring

Background

The aim of the study was to present the PET/CT imaging features in a small series of asymptomatic patients with known cancer pathologies, infected with the SARS-CoV-2 virus, which were incidentally discovered during their monitoring scan of F18-FDG PET/CT.

Methods

We included in our study a number of five cases (3 female and 2 male) out of 478 patients examined by F18-FDG PET/CT between March - April 2020, with confirmed diagnostic of cancer. Four patients had lung damages suggestive for the mentioned viral infection and 1 patient had multiple lung metastases from thyroid cancer. All patients were asymptomatic for acute respiratory disease at the time of examination, being subsequently confirmed for the viral infection by specific PCR analysis.

Results

The asymptomatic positive SARS-CoV-2 cancer patients discovered incidentally in PET/CT F18-FDG represent 0.83% and their imaging characteristics were suggestive for high FDG activity in the lung despite the lack of respiratory symptoms.

Conclusion

The SARS CoV-2 viral infection in asymptomatic cancer patients is a very rare possibility, but represents a challenging scenario both for the differential diagnosis in cancer and also for the epidemiologic context.

Nuclear medicine practices during the COVID-19 pandemic—review of some recently published protocols

Background

With the global surge in COVID-19 pandemic, it has become inevitable for everyone, inclusive of nuclear medicine personnel, to play their role in combating and containing its transmission. During fall 2019, China encountered a novel coronavirus in Wuhan city which was later on termed as COVID-19. The pneumonia caused by COVID-19 is characterized by dry cough, fever, fatigue, and shortness of breathing (dyspnea). Until now, this virus has spread worldwide and continues to cause exponential causalities.

Main body

This global catastrophic scenario calls for stringent measures to control COVID-19 infection. Thus herein, the respective authors have endeavored to review precautionary measures for nuclear medicine department, encompassing its personnel as well as the patients so that intradepartmental transmission can be prevented. This requires development and execution of a robust and dynamic plan elaborating the healthcare guidelines. Hence, our review paper covers the arena of nuclear medicine services in particular.

Conclusion

Nuclear medicine can play its role in mitigating COVID-19 transmission to personnel and patients if provided with ample PPEs and guidelines are strictly followed. With implementing SOPs (standard operating procedures) based on these guidelines, nuclear medicine facilities will be better prepared for impromptu actions in case of any future outbreak while retaining the smooth flow of obligatory healthcare services.

Accidental diagnosis of COVID-19 pneumonia after 18F FDG PET/CT: a case series

Purpose

The aim of this case series is to illustrate possible [18F]-FDG uptake patterns associated to COVID-19.

Methods

Retrospective assessment of all Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) scans performed for any clinical / oncological reason from 1st April 2020 to 30th April 2020. Results of PCR testing for SARS-CoV-2 were retrieved for all patients with lung consolidations and/or peripheral ground glass opacities characterized by increased metabolism to evaluate any possible association with the viral infection.

Results

Seven (4%) out of 172 FDG-PET scans were included. Six out of seven patients (85%) had positive RT-PCR for SARS-CoV-2, while one patient (15%) had possible (not PCR confirmed) COVID-19 pneumonia.

Conclusion

Suspicious accidental COVID-19 findings in Nuclear Medicine Department need to be reported and appropriately evaluated to implement proper supportive treatment and infection control measures.