Comparative analysis of F-18 FDG PET/CT images between scrub typhus and systemic lupus erythematosus.

This study evaluated the use of F-18 fluorodeoxyglucose (FDG) PET/CT imaging to differentiate between scrub typhus and systemic lupus erythematosus (SLE) in patients presenting with lymphadenopathy. We carried out a retrospective analysis of 18 scrub typhus patients and seven SLE patients, using various imaging parameters, including lymph node size, spleen and liver lengths, the distance between the two farthest lesions (Dmax), and assessments of glucose metabolism. On FDG PET images, we measured the maximum standardized uptake value (SUVmax) of the lymph nodes, spleen, and liver and the mean standardized uptake value (SUVmean) of the liver and spleen. The Dmax values of scrub typhus patients were significantly longer than those of SLE patients, indicating that lymphadenopathy is more generalized in the patients with scrub typhus. The SUVmax values for the lymph node, spleen, and liver were also higher in patients with scrub typhus, while the SUVmean of the liver and spleen did not differ between the two groups. This study is the first to compare FDG PET/CT images between these two conditions, suggesting the potential of this imaging modality to provide critical diagnostic distinctions.

Incidentally detected follicular thyroid carcinoma mimicking parathyroid adenoma on Tc-99m MIBI scan: A case report.

RATIONALE: Primary hyperparathyroidism, though relatively prevalent among endocrine disorders, affecting 1% of the general population, often presents diagnostic challenges. Given its potential to precipitate severe complications including nephrolithiasis and fractures, timely diagnosis, and effective management are crucial. PATIENT CONCERNS: A 38-year-old woman with hypercalcemia was referred to the Department of Nuclear Medicine for a Tc-99m MIBI scan. DIAGNOSES: Tc-99m MIBI scan showed focal increased uptake in the left thyroid gland area, initially suggesting a parathyroid adenoma. Further examination using SPECT/CT revealed a nodular lesion within the left thyroid gland showing high Tc-99m MIBI uptake. INTERVENTIONS: Left thyroid lumpectomy confirmed the lesion as follicular thyroid carcinoma. On the second Tc-99m MIBI scan conducted after total thyroidectomy, a parathyroid adenoma was eventually detected in the right lower area, enabling the subsequent appropriate treatment, a right lower parathyroidectomy. OUTCOMES: Thirteen days after the parathyroidectomy, serum levels of total calcium and parathyroid hormone returned to normal. Furthermore, bone mineral density evaluated using DEXA remained within the expected range for her age even after 14 months. LESSONS: When interpreting the Tc-99m MIBI scan, it is essential to keep in mind that various tumors rich in mitochondria, such as thyroid carcinoma, could show a high uptake of Tc-99m MIBI.

Antiviral and synergistic effects of photo-energy with acyclovir on herpes simplex virus type 1 infection.

This experimental study aimed to evaluate the antiviral and synergistic effects of photoenergy irradiation on human herpes simplex virus type I (HSV-1) infection. We assessed viral replication, plaque formation, and relevant viral gene expression to examine the antiviral and synergistic effects of blue light (BL) with acyclovir treatment. Our results showed that daily BL (10 J/cm2) irradiation inhibited plaque-forming ability and decreased viral copy numbers in HSV-1-infected monkey kidney epithelial Vero cells and primary human oral keratinocyte (HOK) cells. Combined treatment with the antiviral agent acyclovir and BL irradiation increased anti-viral activity, reducing viral titers and copy numbers. In particular, accumulated BL irradiation suppressed characteristic viral genes including UL19 and US6, and viral DNA replication-essential genes including UL9, UL30, UL42, and UL52 in HOK cells. Our results suggest that BL irradiation has anti-viral and synergistic properties, making it a promising therapeutic candidate for suppressing viral infections in clinical trials.

A Case of Pediatric Leg-Length Difference After Tibial Fracture Predicted by Bone SPECT/CT.

An 11-year-old boy underwent a bone single-photon emission computed tomography/computed tomography (SPECT/CT) scan 3 months after fracturing his right tibia. The standardized uptake values (SUVs) of the growth plates in his right tibia were higher compared to those in the left tibia. One year later, the right leg was 10 mm longer than the left leg with higher SUVs in the right tibial growth plates. After performing epiphysiodesis at the right proximal tibia, the leg-length difference (LLD) decreased from 17 to 12 mm with the decrease of SUVs in the growth plates of the right tibia. This case emphasizes the potential of quantitative analysis using bone SPECT/CT in predicting LLD and determining the necessity of length equalization surgery in pediatric lower limb fractures.

Serial Migration of Iatrogenic Microembolus on 18 F-FDG PET/CT Images.

ABSTRACT: A 51-year-old woman who had a history of partial nephrectomy underwent an 18 F-FDG PET/CT image for a routine health checkup. Focal intense FDG avidity without any anatomical correlation on CT was detected in the lung. On the delayed image after 20 minutes, the focal activity migrated to a more peripheral portion. An iatrogenic microembolus is a rare but crucial false-positive finding that nuclear physicians should be aware of. Our case emphasizes the importance of meticulous FDG injection and cautious interpretation. In addition, delayed PET/CT imaging through wet reading can aid in diagnosing and help prevent unnecessary investigations.

Prediction of leg-length discrepancy in pediatric femoral shaft fracture using bone SPECT/CT: A case report.

RATIONALE: Children's bones are in the process of growing in both length and width. Therefore, evaluating whether fractures affect the growth plate or not is very crucial. However, even in cases of lower limb fractures where the growth plate remains unaffected, overgrowth or shortening of the affected limb are encountered. PATIENT CONCERNS: An 11-year-old boy was admitted to the emergency department after a passenger car accident. DIAGNOSES: A comminuted fracture of the right femoral shaft was diagnosed by X-ray image. INTERVENTIONS: Closed reduction and internal fixation were performed using intramedullary titanium elastic nails. Six months after the operation, bone union was achieved and the nails were removed. OUTCOMES: Nine months after nail removal, the right leg was unexpectedly noticed 5 mm shorter than the left one. On the initial and follow-up bone single-photon emission computed tomography/computed tomography images with a 9-month interval, radioactivity of growth plate in the right proximal femur was much lower than that of the left femur, suggesting a further increasing of leg-length discrepancy (LLD) in the future. As we expected, LLD had progressively increased up to 20 mm. Epiphysiodesis was finally decided for the left distal femur. Twenty-two months after the length equalization operation, LLD decreased to 5 mm. LESSONS: This case emphasizes that quantitative analysis of growth plate activity using bone single-photon emission computed tomography/computed tomography could predict LLD and help us decide when and which limb should be operated on for pediatric patients with lower limb fractures.

FDG PET/CT in Hantavirus Hemorrhagic Fever With Renal Syndrome.

ABSTRACT: A 58-year-old man with fever, myalgia, and dysuria was admitted to the hospital. Because of prolonged fever, FDG PET/CT was performed. Surprisingly, bilateral kidneys were rapidly enlarged for 5 days with the renal parenchyma showing intense hypermetabolism. FDG PET/CT demonstrated physiology of Hantavirus invading kidneys and causing nephritis. This case illustrates that FDG PET/CT could be the choice of image modality for diagnosis and treatment evaluation of patients suspected of hemorrhagic fever with renal syndrome. To the best of our knowledge, this is the first report of FDG PET/CT image for a patient with hemorrhagic fever with renal syndrome.

Giant Fibrovascular Polyp Mimicking Esophageal Malignancy on 18 F-FDG PET/CT.

ABSTRACT: A 52-year-old man presented with continuous dull pain from the throat to the epigastric region with dysphagia. Initial endoscopy misdiagnosed a subepithelial tumor causing external compression of the esophagus. A CT scan visualized a 14.0 × 4.0-cm pedunculated mass inside the esophagus. Subsequent 18 F-FDG PET/CT identified an intense FDG-avid area in the mass, which strongly suggested esophageal cancer. Total mass excision was performed, and fibrovascular polyp with chronic ulcerative inflammation was finally confirmed on histologic examination.

Blue light irradiation exerts anti-viral and anti-inflammatory properties against herpes simplex virus type 1 infection.

The aim of this study was to investigate the antiviral and anti-inflammatory functions of blue light (BL) in cutaneous viral infections. Previously, we examined the photo-biogoverning role of 450 nm BL in SARS-CoV-2-infected cells, which showed that photo-energy could inhibit viral activation depending on the number of photons. However, the communication network between photo-energy irradiation and immune cells involved in viral infections has not been clarified. We verified viral activation, inflammatory responses, and relevant downstream cascades caused by human simplex virus type I (HSV-1) after BL irradiation. To examine the antiviral effect of BL, we further tested whether BL could disturb viral absorption or entry into host cells. The results showed that BL irradiation, but not green light (GL) exposure, specifically decreased plaque-forming activity and viral copy numbers in HSV-1-infected cells. Accumulated BL irradiation inhibited the localization of viral proteins and the RNA expression of characteristic viral genes such as UL19, UL27, and US6, thus exerting to an anti-viral effect. The results also showed that BL exposure during viral absorption interfered with viral entry or destroyed the virus, as assessed by plaque formation and quantitative PCR assays. The levels of the pro-inflammatory mediators interleukin (IL)-18 and IL-1ß in M1-polarized macrophages were increased by HSV-1 infection. However, these increases were attenuated by BL irradiation. Importantly, BL irradiation decreased cGAS and STING expression, as well as downstream NF-κB p65, in M1-polarized HSV-1-infected macrophages, demonstrating anti-viral and anti-inflammatory properties. These findings suggest that BL could serve as an anti-viral and anti-inflammatory therapeutic candidate to treat HSV-1 infections.

A Rare Case of Familial Schwannomatosis Showing Intrafamilial Variability with Identification of a Shared Novel Germline SMARCB1 Mutation.

Schwannomatosis is characterized by the presence of multiple schwannomas without landmarks of NF2. It is considered the rarest form of neurofibromatosis (NF). Here, we report the first case of familial schwannomatosis with regard to the segmental/generalized phenotype, in which the proband and the daughter present a distinct phenotype in this classification. The proband presents a generalized, painless, extradural type of schwannomatosis, while the daughter shows a segmental, painful, intradural type of schwannomatosis. Whole-exome sequencing of the affected individuals revealed a shared novel SMARCB1 gene mutation (c.92A > G, p.Glu31Gly) despite the clinical variability. We thus suggest two points in the diagnosis of familial schwannomatosis: The identified novel germline SMARCB1 variant can be reflective of a phenotypical progression from a segmental to a generalized type of schwannomatosis, or an intrafamilial variability in inherited schwannomatosis, which was not reported in previous literature. The specific combination of somatic NF2 mutations may be a major factor in regulating the severity and scope of the resulting phenotype in schwannomatosis.

Incidental accumulation of Technetium-99m pertechnetate in subacute cerebral infarction: A case report.

BACKGROUND: When interpreting nuclear medicine images, unexpected findings are sometimes encountered. Recognizing these findings and determining the mechanism of their occurrence could have a significant impact on early diagnosis of critical diseases and the appropriate management of patients. CASE SUMMARY: A 59-year-old man was admitted to the emergency room due to left hemiparesis, left hemifacial palsy, and mild dysarthria. After 2 wk of hospitalization, the patient complained of dry eyes and mouth. Thus, salivary scintigraphy was performed to evaluate the functional status of his salivary glands. Incidental accumulation in the right frontoparietal area was found on salivary scintigraphy. Fluid-attenuated inversion recovery phase magnetic resonance (FLAIR phase MR) image showed diffuse high signal intensity in the same area. Anterior and posterior horns of the right lateral ventricle were obliterated and the midline was slightly shifted to the left side due to right frontoparietal swelling. On salivary scintigraphy, Tc-99m pertechnetate was incidentally accumulated in a subacute cerebral infarction lesion. Two years after the diagnosis of acute infarction, the second series of salivary scintigraphy showed no abnormal activity in the brain. FLAIR phase MR image also demonstrated markedly decreased high signal intensity in the previous infarction lesion without evidence of swelling indicating chronic cerebral infarction. CONCLUSION: This case highlights that Tc-99m pertechnetate could accumulate in a subacute cerebral infarction lesion. The mechanism of an unexpected uptake of Tc-99m pertechnetate in unusual sites should be evaluated and kept in mind for better interpretation.

Clinical and metabolic parameters for predicting disease progression of gallbladder adenocarcinoma.

OBJECTIVE: This study aimed to identify reliable predictors of disease progression in patients with gallbladder (GB) adenocarcinoma. PATIENTS AND METHODS: A total of 54 patients with GB adenocarcinoma underwent preoperative F-18 fluorodeoxyglucose (FDG) PET/CT. Age, sex, clinical stage, and pathologic differentiation were collected. Tumor size and PET parameters such as SUVmax, SUVmean, SUVpeak, metabolic tumor volume (MTV), and total lesion glycolysis were measured. Univariate and multivariate logistic regression analyses were performed to determine the utility of clinical values and PET parameters. Pearson bivariate correlation was used to evaluate the association between progression-free survival (PFS) and various parameters. RESULTS: No recurrence was found in 15 of 54 patients, while six showed recurrence and another 33 manifested disease progression. There were significant differences in size, stage, pathologic differentiation, and PET parameters between the groups with and without recurrence/progression. However, there was no difference in those parameters between the groups with recurrence and progression. The average PFS of the groups with no recurrence, recurrence, and progression groups was 33.1, 17.1, and 5.0 months, respectively. In univariate analysis, age, sex, clinical stage, pathologic differentiation, size, and PET parameters were correlated with PFS. In multivariate analysis, only clinical stage and MTV were statistically significant and MTV showed the highest odds ratio. Pearson correlation coefficients showed moderate negative correlations between PFS and clinical stage or MTV. CONCLUSION: In GB adenocarcinoma, clinical stage and MTV are the most powerful parameters for predicting recurrence and disease progression. Based on clinical stage, MTV will represent a strong prognostic predictor.

Quantitative assessment of dry mouth in scrub typhus using salivary scintigraphy.

Scrub typhus is an acute febrile illness caused by the intracellular pathogen Orientia tsutsugamushi. The clinical features include fever, myalgia, lymphadenopathy, and dry mouth. However, no studies have assessed the symptom of dry mouth in patients with scrub typhus. We investigated the pattern of salivary scintigraphy during the acute febrile state and compared it with any changes after treatment. Fourteen patients underwent both pre- and post-treatment salivary scintigraphy. Imaging analysis was conducted using radioactivity in the oral cavity, parotid glands, and submandibular glands. During the acute phase, the radioactivity in the oral cavity markedly decreased, while that in the parotid and submandibular glands was preserved. After treatment, radioactivity in the oral cavity showed a significant increase at 20-min, 40-min, and after wash-out. The ejection fraction (%) of the parotid glands also increased after treatment. In contrast, the radioactivity levels of the parotid and submandibular glands were not statistically different after treatment. Salivary scintigraphy indicated that insufficient saliva excretion from the salivary glands into the oral cavity was one reason for the dry mouth reported by patients with scrub typhus. In the future, salivary scintigraphy imaging could contribute to the evaluation of dry mouth in patients with scrub typhus.

KSNM60 in Non-thyroidal Radionuclide Therapy: Leaping into the Future.

This year, the Korean Society of Nuclear Medicine (KSNM) is celebrating its 60th anniversary. Treatment, as well as diagnosis, has played a very important role in the development of nuclear medicine. Since I-131 was used for thyroid therapy in 1959, other radionuclide therapy is still being used, and attempts to use new radionuclide are increasing. In this review, we briefly summarize and introduce the therapies such as radioimmunotherapy, transarterial radioembolization, radionuclide therapy for neuroendocrine tumors, peptide receptor radionuclide therapy, control of metastatic bone pain, radiation synovectomy, radionuclide brachytherapy, alpha particle therapy, and boron neutron capture therapy, which has been being attempted so far in the field of nuclear medicine.

Atypical sarcoid reaction mimicking recurrence on F-18 FDG PET/CT in a patient with breast malignancy.

Malignancy may lead to sarcoidosis, which is referred to as sarcoid reaction. This reaction is believed to be a host immune response to the release of soluble antigens from cancer cells. Studies have shown strong 2'-deoxy-2'-[F-18]fluoro-D-glucose (F-18 FDG) uptake in sarcoid reaction and in true sarcoidosis. Therefore, in patients with malignancy, sarcoid reactions can mimic metastasis or recurrence on F-18 FDG positron emission tomography/computed tomography (PET/CT). Herein, we report the case of a 58-year-old woman with a history of left breast cancer whose FDG PET/CT evaluated at 3 months after adjuvant chemotherapy presented hypermetabolic lymphadenopathy in the right supraclavicular and right mediastinal areas. We interpreted these as metastases because the involved lymph nodes were intensely hypermetabolic and appeared newly. Pathologic evaluation of the excised lymph node revealed noncaseating chronic granulomas without malignant cells, indicating a sarcoid reaction. After appropriate steroid therapy, both the size and metabolic activity of the lymphadenopathy substantially decreased. Most sarcoid reactions present as bilateral hilar and peribronchial lymphadenopathies. Our patient presents an atypical example that a sarcoid reaction can also present in a unilateral pattern, making its diagnosis challenging. When interpreting FDG PET/CT images, considering that the sarcoid reaction pattern can vary is crucial.

Xerostomia in a patient with scrub typhus.

Scrub typhus is an acute febrile disease caused by the intracellular organism Orientia tsutsugamushi. The main pathogenesis is focal or disseminated multi-organ vasculitis caused by the infection of endothelial cells and the perivascular infiltration of leukocytes. Many studies have reported interstitial pneumonia, cholecystitis, pancreatitis, and meningoencephalitis in scrub typhus. However, there is no report about sialoadenitis in a patient with scrub typhus. A 79-year-old man was admitted to the emergency room due to a high fever, headache, and myalgia. Scrub typhus was confirmed based on the indirect immunofluorescence assay and the nested polymerase chain reaction. He suffered from severe dry mouth and underwent Tc-99m pertechnetate salivary scintigraphy. While the radiopharmeceutical uptake of the bilateral parotid and submandibular glands was within normal range, salivary excretion into the oral cavity was markedly decreased. After the proper antibiotic treatment, salivary scintigraphy was performed again. Radioactivity in the oral cavity was increased and the ejection fraction (%) after using sialogogue was also improved to the normal range. As far as we know, this is the first report to show salivary scintigraphy of a patient with scrub typhus. By using a Tc-99m pertechnetate salivary scintigraphy, we found that the excretory function of salivary glands was markedly decreased, while the uptake ability was preserved in scrub typhus, unlike Sjögren's syndrome and radiation-induced xerostomia. Salivary scintigraphy presents dry mouth objectively and provides quantitative values as well. Salivary scintigraphy could contribute to the assessment of sialoadenitis before and after treatment of scrub typhus.

Effect of Ursodeoxycholic Acid on the Biodistribution and Excretion of Technetium-99m Radiopharmaceuticals in Rat: A Potential Image Quality Enhancer.

PURPOSE: This study aimed to investigate the effect of ursodeoxycholic acid (UDCA) on the biodistribution and excretion of technetium-99m (Tc-99m)-labeled radiopharmaceuticals. MATERIALS AND METHODS: Tc-99m hydroxy-methylene-diphosphonate (HDP), Tc-99m pertechnetate, and Tc-99m dimercaptosuccinic acid (DMSA) were injected via the tail vein of rats. After 30 min, the control group was administered saline, and the UDCA group was given UDCA orally. Scintigraphy images were acquired after 30 min and 1, 2, 3, and 4 h. Radioactivity and rate of change were compared. Tc-99m mercaptoacetyltriglycine (MAG3) imaging was also performed. RESULTS: In image analysis of Tc-99m HDP, radioactivity of the buttock was lower in the UDCA group at 4 h. Rates of change in the buttock were significantly different at 3 h-30 min and 4 h-30 min, and buttock radioactivity in the UDCA group had decreased more. In analysis of Tc-99m pertechnetate, radioactivity of the buttock was higher in the control group. Rates of change in the thyroid gland and buttock were different at 1 h-30 min, 3 h-30 min, and 4 h-30 min, with radioactivity in the UDCA group decreasing more. In the analysis of Tc-99m DMSA, while the radioactivity of the kidneys in the control group showed little decrease at 1 h-30 min, that in the UDCA group increased. In the analysis of Tc-99m MAG3 images, radioactivity and radioactivity/total body radioactivity (TBA) values for the kidneys were higher in the UDCA group at 2 min. At 5 and 10 min, radioactivity/TBA values for soft tissue in the UDCA group were lower than those in the control group. CONCLUSION: This study demonstrated that administration of UDCA increases renal excretion and soft tissue clearance of radiopharmaceuticals. This investigation could contribute to the broadening of applications of UDCA.

Neural Correlates of Transient Mal de Debarquement Syndrome: Activation of Prefrontal and Deactivation of Cerebellar Networks Correlate With Neuropsychological Assessment.

Background: Mal de debarquement syndrome (MdDS) is characterized by a subjective perception of self-motion after exposure to passive motion, mostly after sea travel. A transient form of MdDS (t-MdDS) is common in healthy individuals without pathophysiological certainty. In the present cross-sectional study, the possible neuropsychiatric and functional neuroimaging changes in local fishermen with t-MdDS were evaluated. Methods: The present study included 28 fishermen from Buan County in South Korea; 15 (15/28, 53.6%) participants experienced t-MdDS for 1-6 h, and 13 were asymptomatic (13/28, 46.4%). Vestibular function tests were performed using video-oculography, the video head impulse test, and ocular and cervical vestibular-evoked myogenic potentials. Visuospatial function was also assessed by the Corsi block test. Brain imaging comprised structural MRI, resting-state functional MRI, and [18F]FDG PET scans. Results: The results of vestibular function tests did not differ between the fishermen with and those without t-MdDS. However, participants with t-MdDS showed better performance in visuospatial memory function than those without t-MdDS (6.40 vs. 5.31, p-value = 0.016) as determined by the Corsi block test. Structural brain MRIs were normal in both groups. [18F]FDG PET showed a relative hypermetabolism in the bilateral occipital and prefrontal cortices and hypometabolism in the vestibulocerebellum (nodulus and uvula) in participants with t-MdDS compared to those without t-MdDS. Resting-state functional connectivities were significantly decreased between the vestibular regions of the flocculus, superior temporal gyrus, and parietal operculum and the visual association areas of the middle occipital gyrus, fusiform gyrus, and cuneus in participants with t-MdDS. Analysis of functional connectivity of the significant regions in the PET scans revealed decreased connectivity between the prefrontal cortex and visual processing areas in the t-MdDS group. Conclusion: Increased visuospatial memory, altered metabolism in the prefrontal cortex, visual cognition cortices, and the vestibulocerebellum, and decreased functional connectivity between these two functional areas might indicate reductions in the integration of vestibular input and enhancement of visuospatial attention in subjects with t-MdDS. Current functional neuroimaging similarities from transient MdDS via chronic MdDS to functional dizziness and anxiety disorders suggest a shared mechanism of enhanced self-awareness as a kind of continuum or as overlap disorders.