Distinct from cardiac PET performed with preparation to control physiological FDG uptake in the myocardium, standard FDG-PET/CT performed with 4–6 h of fasting will show variation in myocardial FDG ...uptake. For this reason, important signs of myocardial and pericardial abnormality revealed by myocardial FDG uptake tend to be overlooked. However, recognition of possible underlying disease will support further patient management to avoid complications due to the disease. This review demonstrates the mechanism of FDG uptake in the myocardium, discusses the factors affecting uptake, and provides notable image findings that may suggest underlying disease.
Numerous studies have clarified the usefulness of
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F-fluorodeoxyglucose (FDG)-PET/CT (positron emission tomography) for diagnosing the cause of fever of unknown origin (FUO). Various types of ...disease can cause FUO, but the cause remains unknown in a certain proportion of FUO, even when the advanced diagnostic methodologies are used. FDG-PET/CT is regarded as a second-line modality in the diagnostic process of FUO, and its potential to identify the cause of FUO will be maximized when the appropriate clinical considerations are understood. Accordingly, this review presents basic knowledge regarding FUO, and reports the current status of FDG-PET/CT applied to diagnosing the cause of FUO, including diagnostic performance, test protocols, possible factors influencing the diagnostic result, outcomes, and cost-effectiveness. This knowledge will enable effective future use of FDG-PET/CT to improve outcomes in patients with FUO.
The COVID-19 pandemic has forced people to significantly change their lifestyles and attitudes, and has greatly burdened healthcare delivery systems worldwide. The redistribution of the medical ...delivery system to maintain normal medical care while responding generously to COVID-19 is a continuing challenge that weighs heavily on medical institutions. Among imaging modalities, chest X-rays and computed tomography (CT) examinations have clearly made a large contribution to treatment of COVID-19. In contrast, it is difficult to express the standpoint of nuclear medicine examinations in a straightforward manner, as the greatest emphasis in this modality has been on how necessary medical care can continue to be provided. Many clinical reports of nuclear medicine examinations related to COVID-19 have been published, and knowledge continues to accumulate. This review provides a summary of the current state of oncology and cardiology positron emission tomography (PET) examinations related to COVID-19, and includes preparation of the nuclear medicine department, trends in PET examinations, specific imaging findings on
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F-fluorodeoxyglucose (FDG) PET/CT, imaging of complications of COVID-19, PET tracers other than FDG, and the effects of vaccines on PET imaging findings.
Salivary gland tumors are rare neoplasms which vary in terms of origin and malignant potential. 2-18F-fluoro-2-deoxy-d-glucose (FDG)-positron emission tomography (PET) has limited ability to ...differentiate between different types of salivary gland tumors because both Warthin’s tumors and pleomorphic adenomas usually show increased FDG uptake, with no statistically significant difference in standardized uptake value (SUV) compared with malignant salivary gland tumors. Here, we discuss 4′-methyl-11C-thiothymidine (4DST) PET, which provides cell proliferation imaging capable of demonstrating intense uptake in parotid carcinoma and Warthin’s tumor, but no uptake in parotid pleomorphic adenoma. This is the first report of the potential of proliferation PET/ computed tomography (CT) imaging for characterizing salivary gland tumors based on the molecular pathogenesis of the tumor.
. Pegfilgrastim administration after chemotherapy increases bone marrow and spleen FDG uptake. Consensus is lacking regarding the optimal interval between pegfilgrastim administration and FDG PET/CT.
.... The purpose of this study was to assess the association between bone marrow and spleen uptake and the interval between pegfilgrastim administration and FDG PET/CT.
. This retrospective study included 70 oncology patients (mean age, 64 ± 12 SD years; 48 men, 22 women) receiving chemotherapy who underwent FDG PET/CT (study scan) within 35 days after pegfilgrastim administration and who underwent additional FDG PET/CT at least 4 months before pegfilgrastim initiation or at least 3 months after last pegfilgrastim administration (reference scan). A nuclear medicine physician recorded the SUV
for normal osseous structures and spleen and assessed bone marrow uptake using a 4-point visual scale (1, no abnormal uptake; 2, clinically insignificant uptake; 3, clinically significant uptake possibly interfering with interpretation; 4, clinically significant uptake expected to interfere with interpretation).
. Percentage change in SUV
between reference and study scans significantly increased (
< .05) as the interval increased for five sites (i.e., for patients with interval of 7-13 vs 29-35 days, mean percentage change was 32.3% ± 18.2% vs 11.5% ± 17.3% for cervical vertebra, 42.2% ± 18.3% vs 21.3% ± 14.2% for thoracic vertebra, 47.2% ± 19.8% vs 19.1% ± 13.9% for lumbar vertebra, 51.1% ± 25.8% vs 12.7% ± 11.3% for pelvis, and 53.0% ± 25.6% vs 4.4% ± 14.1% for lower extremity); percentage change was not associated with the interval for upper extremity or spleen (
> .05). Visual uptake scores of 4, 3, 2, and 1 were observed in days 7-21, 12-22, 12-28, and 14-35, respectively. Percentage of patients with a score of 3 or 4 was 94.4% for days 7-13, 58.1% for days 14-21, 6.7% for days 22-28, and 0% for days 29-35. A total of 71.4% of patients had a score of 3 or 4 on day 7-21, whereas 4.8% had a score of 3 and 0% had a score of 4 on days 22-35.
. A visual uptake score of 3 or 4 was consistently observed throughout an approximately 3-week interval following pegfilgrastim administration, without any such case beyond 22 days.
. We recommend a preferred interval of at least 3 weeks after pegfilgrastim administration before PET/CT.
COVID-19 vaccination using mRNA technology began at the end of 2020 in several countries, approximately 9 months after the WHO declared the new coronavirus a pandemic, and began in Japan at the end ...of February 2021. Several studies have reported FDG avidity in enlarged axillary lymph nodes as a specific feature of FDG-PET/CT imaging after COVID-19 vaccination. A major concern is that this finding could lead to a misdiagnosis in patients with various types of malignancy. We review the impact of COVID-19 vaccination on the management of patients scheduled for FDG-PET/CT in the setting of nationwide mass vaccination.
Purpose
The aim of this study was to evaluate the ability of texture analysis using pretreatment
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F-FDG PET/CT to predict prognosis in patients with surgically treated rectal cancer.
Methods
We ...analyzed 94 patients with pathologically proven rectal cancer who underwent pretreatment
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F-FDG PET/CT and were subsequently treated with surgery. The volume of interest of the primary tumor was defined using a threshold of 40% of the maximum standardized uptake value (SUVmax), and conventional (SUVmax, metabolic tumor volume MTV, total lesion glycolysis TLG) and textural PET features were extracted. Harmonization of PET features was performed with the ComBat method. The study endpoints were overall survival (OS) and progression-free survival (PFS), and the prognostic value of PET features was evaluated by Cox regression analysis.
Results
In the follow-up period (median 41.7 interquartile range, 30.5–60.4 months), 21 (22.3%) and 30 (31.9%) patients had cancer-related death or disease progression, respectively. Univariate analysis revealed a significant association of (1) MTV, TLG, and gray-level co-occurrence matrix (GLCM) entropy with OS; and (2) SUVmax, MTV, TLG, and GLCM entropy with PFS. In multivariate analysis including clinical characteristics, GLCM entropy (≥ 2.13) was the only relevant prognostic PET feature for poor OS (hazard ratio HR: 4.16,
p
= 0.035) and PFS (HR: 2.70,
p
= 0.046).
Conclusion
GLCM entropy, which indicates metabolic intratumoral heterogeneity, was an independent prognostic factor in patients with surgically treated rectal cancer. Compared with conventional PET features, GLCM entropy has better predictive value and shows potential to facilitate precision medicine.
Objective
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FFluciclovine (
anti
-
18
FFACBC) has demonstrated diagnostic efficacy for cancers of the brain where
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Ffludeoxyglucose has limitations. We conducted a phase IIa study of
anti
-
18
...FFACBC to assess its accumulation pattern and safety in patients with malignant glioma.
Methods
Five patients with glioma scheduled for brain tumor resection received
anti
-
18
FFACBC. Brain positron emission tomography (PET) was performed following intravenous administration of
anti
-
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FFACBC, and subsequently, preoperative gadolinium contrast-enhanced T1-weighted (CE-T1W) magnetic resonance imaging (MRI) was performed for surgery. Specimens for histopathological evaluation were collected during surgery, and their location was precisely determined on CE-T1W MRI and
anti
-
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FFACBC PET/CT images. In addition, tumor extent defined on the MRI and PET/CT images was compared. To determine time–activity curves for
anti
-
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FFACBC uptake in brain tumor and normal tissues, regions of interest were set in the brain tumor, contralateral normal tissue and the cerebellum, and their standardized uptake values (SUV) were calculated. The safety of
anti
-
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FFACBC was assessed based on subjective symptoms and objective findings, electrocardiograms, vital signs, laboratory results, and the incidence of adverse events.
Results
Anti
-
18
FFACBC accumulated in the malignant gliomas of all patients. CE-T1W MRI detected gliomas in all patients, but
anti
-
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FFACBC PET/CT generally delineated wider regions of tumor extent than CE-T1W MRI. Two of the histopathologically confirmed tumors were located in regions that were defined using
anti
-
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FFACBC PET/CT, but not using CE-T1W MRI. Two patients experienced three mild adverse events: one complained of a dull headache and later a mild headache, and the other showed general malaise. These symptoms resolved spontaneously without treatment. Only the mild headache could not be ruled out from having a causal relationship with
anti
-
18
FFACBC. Favorable
T
/
N
ratios regarding
anti
-
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FFACBC uptake between tumors and normal control tissues were demonstrated in this trial.
Conclusions
It is suggested that
anti
-
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FFACBC PET/CT has the ability to delineate glioma spread that is undetectable using CE-T1W MRI.
Anti
-
18
FFACBC is safe in patients with malignant glioma.
This study was registered in the Japan Pharmaceutical Information Center Clinical Trials Information, which is one of the World Health Organization registries (registration number: JapicCTI-111387).
Following a lot of reports of coronavirus disease 2019 (COVID-19) CT images, the feature of FDG-PET/CT imaging of COVID-19 was reported in several articles. Since FDG accumulates in activated ...inflammatory cells, FDG-PET/CT has huge potential for diagnosing and monitoring of inflammatory disease. However, FDG-PET/CT cannot be routinely used in an emergency setting and is not generally recommended as a first choice for diagnosis of infectious diseases. In this review, we demonstrate FDG-PET/CT imaging features of COVID-19, including our experience and current knowledge, and discuss the value of FDG-PET/CT in terms of estimating the pathologic mechanism.
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