Bivalent mRNA COVID-19 Vaccine-Related Pericarditis on 18 F-FDG PET/CT.

ABSTRACT: A 13-year-old boy was suspected with pericarditis after a second booster dose of bivalent mRNA COVID-19 vaccine. After specific preparation for cardiac inflammation with carbohydrate-free, high-fat diet, the 18 F-FDG PET/CT successfully demonstrated simultaneous presentation of vaccination-related axillary lymphadenopathy and pericarditis without the interference of physiological myocardial uptake.

Consolidative chemotherapy after definitive concurrent chemoradiotherapy for esophageal squamous cell carcinoma patients: a population based cohort study.

BACKGROUND: The role of consolidative chemotherapy (CCT) for locally advanced esophageal squamous cell carcinoma (LA-ESCC) patients treated with definitive concurrent chemoradiotherapy (dCCRT) is unclear. We aimed to compare the overall survival (OS) of those treated with vs without CCT via a population based approach. METHODS: Eligible LA-ESCC patients diagnosed between 2011 and 2017 were identified via the Taiwan Cancer Registry. We used propensity score (PS) weighting to balance observable potential confounders between groups. The hazard ratio (HR) of death and incidence of esophageal cancer mortality (IECM) were compared between those with vs without CCT. We also evaluated the OS in supplementary analyses via alternative approaches. RESULTS: Our primary analysis consisted of 368 patients in whom covariates were well balanced after PS weighting. The HR of death when CCT was compared to without was 0.67 (95% confidence interval 0.52-0.86, P = 0.002). The HR of IECM was 0.66 (P = 0.04). The HR of OS remained similarly in favor of CCT in supplementary analyses. CONCLUSIONS: We found that CCT was associated with significantly improved OS for LA-ESCC patients treated with dCCRT. Randomized controlled trials were needed to confirm this finding.

Rare "Burned-Out" Testicular Mixed Germ Cell Tumor on 18 F-FDG PET/CT.

ABSTRACT: Spontaneous regression of testicular mixed germ cell tumor is rare and is also called burned-out testicular tumor. We herein present the case of a 20-year-old man who was initially diagnosed with metastatic embryonal carcinoma. 18 F-FDG PET/CT demonstrated apparent metastases in the lymph node regions and both lungs. A covert right testicular lesion was noted according to the features on the CT component of PET/CT, which was subsequently confirmed as burned-out testicular mixed germ cell tumor.

18F-Fluciclovine Uptake in Intramuscular Injecting Site of Antiandrogen.

ABSTRACT: 18F-fluciclovine, a radiolabeled amino acid analog, has been approved by US Food and Drug Administration for detecting lesions of biochemical recurrence of prostate adenocarcinoma with PET/CT. However, it is not specific for prostate cancer and has been found to be present in variety of malignant and benign etiologies. We herein present an interesting case of the incidental finding of increasing uptake of 18F-fluciclovine related to intramuscular injection of antiandrogen.

Brain Lymphoma on 99mTc-TRODAT-1 SPECT.

Tc-TRODAT-1, as a tropane-derived compound with highly selective binding to the dopamine transporter, has been extensively used as an in vivo biomarker to evaluate parkinsonism. There have been few reports indicating various etiologies about extrastriatal findings on the Tc-TRODAT-1 SPECT. We herein present an interesting case about the incidental discovery of brain lymphoma with increasing uptake of Tc-TRODAT-1.

Peritoneal Deciduoid Malignant Mesothelioma on 67Ga SPECT/CT.

Malignant mesotheliomas may be classified into epithelioid (60%), sarcomatoid (20%), or mixed (20%) type microscopically. Malignant deciduoid mesothelioma, a rare phenotype of epithelioid mesothelioma, arises more commonly from the peritoneum of young women, but is also from the pleura of elderly people. In the current report, the authors describe an unusual case of peritoneal malignant epithelioid mesothelioma with rare deciduoid phenotype demonstrated with Ga SPECT/CT.

Treating hepatocellular carcinoma with 90Y-bearing microspheres: a review.

Hepatocellular carcinoma (HCC) is a disease usually diagnosed in its advanced-stage, and is frequently not amenable to curative surgical treatment. Also, HCC is resistant to chemotherapy and less vulnerable to radiation therapy compared to normal hepatic parenchyma. Both of these facts render the efficacy of adjuvant and palliative treatments problematic. Selective internal radiation therapy (SIRT) with 90Y-bearing microspheres is characterized by preferentially delivering substantially high doses of radiation to a liver tumor dose simultaneously limiting the damage to its non-tumorous cells, providing an opportunity for effective local tumor control and even tumor regression therapy. The current article reviews the specific characters, dosimetry, possible applications, and special considerations toward the pre-existing radiation therapy of 90Y microsphere SIRT in treating HCC.

A volume-equivalent spherical necrosis-tumor-normal liver model for estimating absorbed dose in yttrium-90 microsphere therapy.

PURPOSE: Primary hepatocellular carcinoma and metastatic liver tumors are highly malignant tumors in Asia. The incidence of fatal liver cancer is also increasing in the United States. The aim of this study was to establish a spherical tumor model and determine its accuracy in predicting the absorbed dose in yttrium-90 (Y-90) microsphere therapy for liver cancer. METHODS: Liver morphology can be approximated by a spherical model comprising three concentric regions representing necrotic, tumor, and normal liver tissues. The volumes of these three regions represent those in the actual liver. A spherical tumor model was proposed to calculate the absorbed fractions in the spherical tumor, necrotic, and normal tissue regions. The THORplan treatment planning system and Monte Carlo N-particle extended codes were used for this spherical tumor model. Using the volume-equivalent method, a spherical tumor model was created to calculate the total absorbed fraction [under different tumor-to-healthy-liver ratios (TLRs)]. The patient-specific model (THORplan) results were used to verify the spherical tumor model results. RESULTS: The results for both the Y-90 spectrum and the Y-90 mean energy indicated that the absorbed fraction was a function of the tumor radius and mass. The absorbed fraction increased with tumor radius. The total absorbed fractions calculated using the spherical tumor model for necrotic, liver tumor, and normal liver tissues were in good agreement with the THORplan results, with differences of less than 3% for TLRs of 2-5. The results for the effect of TLR indicate that for the same tumor configuration, the total absorbed fraction decreased with increasing TLR; for the same shell tumor thickness and TLR, the total absorbed fraction was approximately constant; and for tumors with the same radius, the total fraction absorbed by the tumor increased with the shell thickness. CONCLUSIONS: The results from spherical tumor models with different tumor-to-healthy-liver ratios were highly consistent with the reference results (THORplan). These findings indicate that a spherical tumor model can provide good estimates of Y-90 doses in microsphere therapy and can be considered a first approximation for dose estimation in Y-90 microsphere therapy.

A Mimic of Intra-abdominal Malignancy: Physiological Urinary Excretion of FDG in the Rare Adult Vesicourachal Diverticulum.

Urachal remnant anomalies are rare, and vesicourachal diverticulum is the most uncommon subtype of these anomalies. We present such a rare case of vesicourachal diverticulum that is incidentally discovered during the staging surveillance of a known esophageal cancer with F-FDG PET/CT. The physiological urinary excretion of radiopharmaceutical in the vesicourachal diverticulum mimics intra-abdominal malignancy, which resolves spontaneously in the follow-up FDG PET/CT.

Asymptomatic Solitary Metastasis to the Testis From Prostate Carcinoma Detected by FDG PET/CT.

Testicular metastases, despite their proximity, from prostate adenocarcinoma are rare and usually found along with bone or other visceral metastases. We herein present a case with recurrent disease of prostate adenocarcinoma as solitary testicular metastasis detected by 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT).

Left ventricular ejection fraction estimation using mutual information on technetium-99m multiple-gated SPECT scans.

BACKGROUND: A new non-linear approach was applied to calculate the left ventricular ejection fraction (LVEF) using multigated acquisition (MUGA) images. METHODS: In this study, 50 patients originally for the estimation of the percentage of LVEF to monitor the effects of various cardiotoxic drugs in chemotherapy were retrospectively selected. All patients had both MUGA and echocardiography examinations (ECHO LVEF) at the same time. Mutual information (MI) theory was utilized to calculate the LVEF using MUGA imaging (MUGA MI). RESULTS: MUGA MI estimation was significantly different from MUGA LVEF and ECHO LVEF, respectively (p < 0.005). The higher repeatability for MUGA MI can be observed in the figure by the higher correlation coefficient for MUGA MI (r = 0.95) compared with that of MUGA LVEF (r = 0.80). Again, the reproducibility was better for MUGA MI (r = 0.90, 0.92) than MUGA LVEF (r = 0.77, 0.83). The higher correlation coefficients were obtained between proposed MUGA MI and ECHO LVEF compared to that between the conventional MUGA LVEF and ECHO LVEF. CONCLUSIONS: MUGA image with the aid of MI is promising to be more interchangeable LVEF to ECHO LVEF measurement as compared with the conventional approach on MUGA image.

Pituitary macroadenoma on 99mTc-TRODAT-1 brain SPECT.

Dopamine transporter (DAT) radiopharmaceuticals are capable of binding to the DAT with high selectivity, especially in the corpora striata, and have been widely used to evaluate parkinsonian disorder. However, only a few reports have mentioned about the extrastriatal pathologic DAT uptake. Herein we present an interesting case about the incidental discovery of pituitary macroadenoma with intense uptake of 99mTc-TRODAT-1.

Less may be as good as more: feasible and effective method to differentiate gastric uptake solely on planar gallium scan in the era of SPECT/CT.

We presented a patient with abnormal focal accumulation of 67Ga in the left upper abdomen. After drinking water, we successfully identified the abnormal radioactivity that was from the stomach. Subsequent endoscopic examination did not reveal gastric pathological condition. Gastric accumulation of 67Ga may relate to pathological conditions or physiological uptake, confounding interpretation of 67Ga scintigraphy. Simple water ingestion method can rapidly identify gastric 67Ga uptake, and the shape of distended stomach can also help to differentiate pathological conditions from physiological uptake, which is especially helpful for a busy nuclear medicine department and for places where the SPECT/CT systems are not available.

Parotid gland metastasis from squamous cell carcinoma of esophagus detected by FDG PET/CT.

A 55-year-old man was diagnosed with squamous cell carcinoma in the middle thoracic esophagus. The FDG PET/CT revealed an incidental strong FDG-avid finding (SUVmax, 11) in the right parotid gland, which was subsequently confirmed as metastasis from the squamous cell carcinoma of esophagus via surgery. The current case adds another differential diagnosis of parotid FDG-avid lesion to the existing literature.

FDG PET/CT of a late-term pregnant woman with breast cancer.

A 38-year-old pregnant woman at 26-week gestation with left breast cancer requested an FDG PET/CT scan for more detailed staging of her breast cancer before treatment. After discussing the potential radiation-related risk and estimating possible absorbed dose to fetus, she consented for examination. By using a low-radiation-dose CT protocol and administration of routine 370-MBq FDG without diuresis, the resultant calculated (using existing models to predict fetal radiation exposure) fetal dose from CT and FDG would be 3.60 mGy and 6.29 mGy, respectively. In contrast to the existing few literatures, our case also demonstrated previously unreported uptake in the fetal kidneys.

Bilateral breast uptake demonstrated on FDG PET/CT scans in 3 male patients with hepatocellular carcinomas.

We reported 3 male patients with hepatocellular carcinoma who underwent FDG PET/CT for systemic survey before liver transplantation. All of their scans demonstrated obvious FDG uptake in bilateral breasts. These uptakes might be owing to gynecomastia caused by an increase in free estrogen related to the cirrhotic liver.

Sex- and age-related differences in brain FDG metabolism of healthy adults: an SPM analysis.

BACKGROUND AND PURPOSE: The purpose of our study was aimed to analyze the sex- and age-related differences of brain metabolism in healthy individuals. METHODS: Consecutive 100 healthy subjects, 50 males and 50 females, undergoing routine 2-[(18)F]-fluoro-2-deoxy-d-glucose positron emission tomography (FDG PET) for health checkup in our hospital were retrospectively enrolled in this study. Statistical parametric mapping (SPM) was used for analyses of the FDG PET images to disclose the possible effects of age on brain metabolism in males and females as well as the differences of brain metabolism between male and female groups. RESULTS: In males and females, decreased brain metabolism with aging is found in bilateral lateral orbital prefrontal and right anterior cingulate cortices. In comparisons between sexes, males are found to have more brain metabolism than females in bilateral visual cortices and cerebellum. CONCLUSIONS: Our report discloses different sex- and age-related brain metabolism. Decreased brain metabolism with aging in males and females is similar to findings reported in previous literatures. However, whether declined brain function or volume with aging causing metabolic changes is unknown and should be further evaluated. Nevertheless, the sex-related differences are possibly compatible with the historical observation of better performance in visual-spatial tasks in males than females.